Everyday Items Around Your Citizens’ Homes That Attract Mosquitoes

mosquito-breeding-sites-public-education-awareness

Where Do Mosquitoes Lay Eggs?

All mosquito species require water to breed and complete their lifecycle. Mosquitoes lay their eggs in or near stagnant water, where they hatch into fully aquatic larvae. The larvae feed and develop in the water until they pupate, leaving only after the fully mature adult emerges from the pupa and flies off. However, different mosquito species require different water sources, and each source can be categorized into one of three groups: permanent water mosquitoes, floodwater mosquitoes, and container mosquitoes.

Permanent Water:
These mosquitoes seek out large standing water sources, such as stagnant ponds and marshes, to breed. Many species will lay their eggs directly on the water’s surface, while others will lay their eggs on aquatic plants. Most mosquitoes will seek out freshwater sources; however, some mosquito species are able to breed in coastal salt marshes.

permanent-water-mosquito-on-water-surface (2)

Floodwater:
While all mosquito eggs need water to hatch, some species are capable of “waiting it out.” Floodwater mosquitoes lay their eggs on or just above the water line of plants or other aquatic structures near ditches or floodplains. The eggs are able to survive in a dormant state when these places are relatively dry, and then hatch when they flood. This can lead to large, localized spikes in mosquito numbers after heavy rainfall, when many of these mosquitoes’ eggs hatch simultaneously.

floodwater-mosquito-breeding-sites (3)

Containers:
Container-breeding mosquitoes lay their eggs in nearly anything capable of holding water. Common sources often include artificial containers such as discarded tires, buckets, and bird baths and natural containers such as tree holes or leaf axils of plants. Container mosquitoes are especially problematic in urban areas and suburban areas where many of these containers are found within the environment. Fortunately, there are plenty of precautions citizens can take to eliminate these breeding sites.

containers-mosquito-breeding-sites (2)

Common Mosquito Breeding Containers Near Homes

Container mosquitoes will use nearly anything that holds water as a breeding site. Containers do not need to be especially large or permanent to host container mosquito larvae. Here are just a few of the small but common containers these mosquitoes will seek out:

  • Buckets
  • Flowerpots and planters
  • Leaf-clogged gutters 
  • Old tires
  • Wheelbarrows
  • Bird baths
  • Trash cans
  • Swimming pools
  • Pet dishes

Because some container mosquitoes like Aedes aegypti and Aedes albopictus are potential disease vectors, it can be just as important to monitor container sources as it is permanent water and floodwater sources. Fortunately, there’s plenty the average citizen can do to help eliminate container breeding sites.

What Can Citizens Do to Reduce Mosquito Breeding Sites?

Because of mosquitoes’ quick life cycle, it’s important to limit breeding sites on an ongoing basis, and especially after substantial rainfall. Cleaning up a property and removing any discarded cups, jars, old tires, or other debris is a great start. Ensuring that gardening equipment like wheelbarrows and buckets are either covered or turned over when not in use can prevent them from becoming breeding sites later on. Clearing clogged gutters or planters is a great next step, and draining any larger water sources like unused swimming pools can also go a long way toward limiting the spread of container mosquitoes and potential mosquito-bite diseases.

dumping-standing-water-reduce-mosquito-breeding-sites

Sources:
“Where Mosquitoes Live.” Center for Disease Control. https://www.cdc.gov/mosquitoes/about/where-mosquitoes-live_1.html. Accessed 2 February 2026.

Schattenberg, Paul. “Texas Mosquito Populations Boom After Rains.” Texas A&M Stories.  https://stories.tamu.edu/news/2023/06/28/texas-mosquito-populations-boom-after-rains/. Accessed 2 February 2026.

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Contact Our Experts

Complete the form below or call us at 800-413-4445 to speak to an expert about your mosquito management needs.

VDCI_Logo_squareSince 1992, Vector Disease Control International (VDCI) has taken pride in providing municipalities, mosquito abatement districts, industrial sites, planned communities, homeowners associations, and golf courses with the tools they need to run effective mosquito control programs. We are determined to protect the public health of the communities in which we operate. Our mosquito control professionals have over 100 years of combined experience in the field of public health, specifically vector disease control. We strive to provide the most effective and scientifically sound mosquito surveillance and control programs possible based on an Integrated Mosquito Management approach recommended by the American Mosquito Control Association (AMCA) and Centers for Disease Control and Prevention (CDC). VDCI is the only company in the country that can manage all aspects of an integrated mosquito management program, from surveillance to disease testing to aerial application in emergency situations.

2025 Mosquito-Borne Disease Year In Review

West-Nile-Virus-UK-spread-Europe-outbreak-1001738

Exploring the Impact of Mosquito-Borne Diseases In 2025

Mosquito populations and mosquito-bite disease risks are always changing due to weather, urban development, targeted management efforts, and other factors. Year-to-year variation is normal, and the 2025 data from the Centers for Disease Control and Prevention (CDC) reflect several notable changes in reported cases compared to 2024:

  • La Crosse Encephalitis: 203% increase; 194% increase in neuroinvasive
  • St. Louis Encephalitis: 200% increase; 200% increase in neuroinvasive
  • West Nile virus: 42% increase; 35% increase in neuroinvasive

Our 2025 year in review provides trends and insights that can help inform your mosquito management decisions in 2026.

West Nile Virus (WNv)

OVERVIEW:

  • The virus appeared in the U.S. in 1999, with the first case in New York City, leading to 62 human cases and 25 horse cases that year.
  • WNv is now the most common mosquito-borne disease in the country, with an estimated 2,000 cases reported each year.

TRANSMISSION:

  • The West Nile virus spreads primarily through mosquitoes that feed on infected birds, not through casual human-to-human contact.
  • In the U.S., Culex pipiens, Culex tarsalis, and Culex quinquefasciatus are the primary vectors.

RISKS:

  • Most cases are asymptomatic, but symptoms can include flu-like illness, fever, rash, headache, and neck stiffness.
  • Severe infections can cause encephalitis (brain swelling), affect the central nervous system, and may be fatal. Approximately 1 in 150 infections becomes neuroinvasive.

Year-Over-Year Change in West Nile Virus Cases

2025
2,076 cases (1,434 neuroinvasive)
2024
1,466 cases (1,063 neuroinvasive)
2023
2,406 cases (1,599 neuroinvasive)
2022
1,132 cases (827 neuroinvasive)
2021
2,911 cases (2,008 neuroinvasive)
2020
731 cases (559 neuroinvasive)

Top 5 States for West Nile Virus Human Case Count

2025 West Nile Virus Human Cases In the U.S.
2025-west-nile-virus-human-disease-case-reported-by-state-map
Image Source: U.S. Centers for Disease Control and Prevention https://www.cdc.gov/west-nile-virus/data-maps/current-year-data.html
Cases
0
Neuroinvasive Cases
0
States Reporting Human Cases
0

Dengue

NOTE: Most dengue cases in the 49 continental U.S. states are imported through travel. Although local transmission can occur, it is largely limited to U.S. territories and states where dengue is common. Below, cases are categorized separately as either locally acquired or travel-associated.

OVERVIEW 

  • Dengue is common in the U.S. territories of American Samoa, Puerto Rico, and the U.S. Virgin Islands.
  • Most dengue cases reported in the 49 continental US states occur in travelers infected in areas with risk of dengue.
  • Dengue has become the fastest-growing mosquito-transmitted disease, with nearly 400 million infections annually worldwide. 

TRANSMISSION

  • There are 4 common Dengue viruses, denoted as Dengue 1, 2, 3, and 4.
  • Dengue is transmitted to humans through infected Aedes mosquitoes, specifically Aedes aegypti and Aedes albopictus.

RISKS

  • Infection can cause “break-bone fever” (severe muscle/joint pain, high fever, rash, headache), with approximately 5% of cases developing severe dengue hemorrhagic fever, which can lead to internal bleeding and death.
  • Severe cases are more likely in young children and older adults.
  • The virus can be passed to fetuses during pregnancy.
2025 Dengue Human Cases In the U.S.
LOCALLY ACQUIRED

The chart below provides a year-over-year comparison of locally acquired dengue cases to highlight changes in local transmission activity.

Year-Over-Year Change in Dengue Cases

2025
3,809 locally acquired cases
2024
6,076 locally acquired cases
2023
1,104 locally acquired cases
2022
1,044 locally acquired cases
2021
609 locally acquired cases
2020
983 locally acquired cases

Top 5 States for Dengue Human Case Count

2025-dengue-human cases-locally-aquired-us-map
Image Source: U.S. Centers for Disease Control and Prevention, Accessed on January 1, 2025 https://www.cdc.gov/dengue/data-research/facts-stats/current-data.html
Locally Acquired Cases
0
Jurisdictions Reporting Locally Acquired Human Cases
0
2025 Dengue Human Cases In the U.S.
TRAVEL ASSOCIATED

The chart below provides a year-over-year comparison of travel-associated dengue cases to highlight changes in travel-related exposure patterns.

Year-Over-Year Change in Dengue Cases

2025
1,204 travel-related
2024
3,179 travel-related
2023
1,452 travel-related
2022
1,494 travel-related
2021
205 travel-related
2020
354 travel-related

Top 5 States for Dengue Human Case Count

2025-dengue-human cases-travel-associated-us-map
Travel Associated Cases
0
Jurisdictions Reporting Travel Associated Human Cases
0

Eastern Equine Encephalitis (EEE)

OVERVIEW 

  • Eastern Equine Encephalitis (EEE) was first recognized in horses in 1831, with the first confirmed human cases in 1938.
  • Today, EEE is found in North, Central, and South America, as well as the Caribbean.

TRANSMISSION

  • Culiseta melanura primarily infects birds, while bridge vectors like Coquillettidia pertubans, Aedes sollicitans, and Ochlerotatus canadensis transmit it to humans and horses.
  • People living or working near wetlands and swamps are at higher risk, and infections occur mainly during the summer months.

RISKS

  • Severe cases involve brain and spinal cord inflammation, with sudden high fever, stiff neck, disorientation, seizures, and coma.
  • Only about 5% of EEE infections lead to severe encephalitis; of those, 33% die, making it the deadliest arbovirus in the U.S.
  • The elderly (50+) and children (15 and younger) are most at risk for developing encephalitis.
  • There is no vaccine or antiviral treatment for humans.

Year-Over-Year Change in Eastern Equine Encephalitis Cases

2025
3 cases (3 neuroinvasive)
2024
19 cases (19 neuroinvasive)
2023
7 cases (7 neuroinvasive)
2022
1 case (1 neuroinvasive)
2021
5 cases (5 neuroinvasive)
2020
13 cases (13 neuroinvasive)

Top 3 States for Eastern Equine Encephalitis Human Case Count

2025 Eastern Equine Encephalitis Human Cases Reported In the U.S.
2025-eee-virus-human-disease-case-report-mao
Image Source: U.S. Centers for Disease Control and Prevention, Accessed on January 1, 205 https://www.cdc.gov/eastern-equine-encephalitis/data-maps/current-year-data.html
Cases
0
Neuroinvasive Cases
0
States Reporting Human Cases
0

La Crosse Encephalitis (LAC)

OVERVIEW 

  • La Crosse Encephalitis (LAC) was first identified in the United States in 1964.
  • Most commonly reported in the upper Midwest and Mid-Atlantic states, including Ohio, West Virginia, and Minnesota.

TRANSMISSION

  • Primarily spread by the Eastern treehole mosquito, Aedes triseriatus.
  • Aedes triseriatus can pass the virus to its offspring, which allows it to persist across mosquito generations.
  • Reservoir hosts like chipmunks and squirrels are also carriers. 

RISKS

  • LAC primarily affects children under 16, making it a rare but serious pediatric mosquito-borne disease.
  • Flu-like symptoms, including headache, fever, nausea, vomiting, and fatigue, may appear 5-15 days after infection.
  • Severe infections can cause brain inflammation, seizures, cognitive impairment, vision loss, paralysis, or coma, though mortality is less than 1%.
  • There is no vaccine or antiviral treatment.

Year-Over-Year Change in La Crosse Encephalitis​ Cases

2025
106 cases (100 neuroinvasive)
2024
35 cases (34 neuroinvasive)
2023
31 cases (30 neuroinvasive)
2022
22 cases (19 neuroinvasive)
2021
40 cases (39 neuroinvasive)
2020
88 cases (84 neuroinvasive)

Top States for La Crosse Encephalitis Human Case Count

2025 La Crosse Encephalitis Human Cases In the U.S.
2025-la-crosse-encephalitis-human-cases-in-us-map
Image Source: U.S. Centers for Disease Control and Prevention, Accessed on January 1, 2025 https://www.cdc.gov/la-crosse-encephalitis/data-maps/current-year-data.html
Cases
0
Neuroinvasive Cases
0
States Reporting Human Cases
0

St. Louis Encephalitis (SLEV)

OVERVIEW 

  • The St. Louis encephalitis virus (SLEV) was first recognized in 1933 during a St. Louis, Missouri, epidemic that resulted in over 1,000 cases of encephalitis.
  • Before West Nile virus appeared in 1999, SLEV was considered the most significant epidemic mosquito-borne virus in the U.S., with the last major epidemic in 1975 along the Ohio–Mississippi River Basin (nearly 2,000 cases, 142 deaths).

TRANSMISSION

  • Primary vectors include Culex pipiens, Culex quinquefasciatus, Culex tarsalis, and Culex nigripalpus.
  • Wild birds, such as blue jays, sparrows, robins, and pigeons, act as amplifying hosts, but typically remain asymptomatic.

RISKS

  • Most infections are asymptomatic; severe cases can cause high fever, neck stiffness, disorientation, coma, or death, with mortality ranging from 3-30% depending on age.
  • Adults over 50 are more likely to develop severe disease, with mortality between 7-24%, while those under 50 generally face less than 5% mortality.

Year-Over-Year Change in St. Louis Encephalitis​ Cases

2025
3 case (2 neuroinvasive)
2024
1 case (0 neuroinvasive)
2023
19 cases (13 neuroinvasive)
2022
33 cases (27 neuroinvasive)
2021
17 cases (11 neuroinvasive)
2020
16 cases (14 neuroinvasive)

Top State for St. Louis Encephalitis Human Case Count

2025 St. Louis Encephalitis Human Cases In the U.S.
2025-st-louis-encephalitis-human-cases-map
Image Source: U.S. Centers for Disease Control and Prevention, Accessed on January 24, 2024 https://www.cdc.gov/sle/data-maps/current-year-data.html
Case
0
Neuroinvasive Cases
0
States Reporting Human Cases
0

Jamestown Canyon virus (JCV)

OVERVIEW

  • Jamestown Canyon virus (JCV) was first discovered in Culiseta mosquitoes in Jamestown, Colorado, in 1961.
  • It is found throughout much of the U.S., with most cases reported in the upper Midwest.

TRANSMISSION

  • Various mosquito species serve as vectors: Aedes, Culex, Coquillettidia.
  • JCV can be transmitted from mosquito parents to offspring. 
  • Deer often serve as the amplifying host, while humans are “dead-end” hosts and cannot transmit the virus to other mosquitoes.

RISKS

  • Symptoms include fever, headache, and fatigue.
  • Most JCV cases are neuroinvasive. About 68% of reported infections affect the nervous system, with symptoms ranging from fever and rash to meningitis or encephalitis.
  • No treatment currently exists.

Year-Over-Year Change in Jamestown Canyon Virus Cases

2024
22 cases (15 neuroinvasive)
2023
21 cases (15 neuroinvasive)
2022
12 cases (11 neuroinvasive)
2021
32 cases (21 neuroinvasive)
2020
13 cases (10 neuroinvasive)

Top States for Jamestown Canyon Virus Human Case Count:

2025 Jamestown Canyon virus Human Cases Reported In the U.S.
2025-jamestown-canyon-virus-human-disease-case-report-map
Image Source: U.S. Centers for Disease Control and Prevention, Accessed on January 24, 2025 https://www.cdc.gov/jamestown-canyon/data-maps/current-year-data.html
Locally Acquired Cases
0
Neuroinvasive Cases
0
States Reporting Human Cases
0

DATA IS THE BACKBONE OF EFFECTIVE MOSQUITO CONTROL PROGRAMS

Data from 2025 and prior years reveal that disease risks are continually shifting and evolving across the country. Protecting our local communities not only requires reactive solutions but also tailored, preventative strategies driven by data. 

Integrated Mosquito Management programs incorporate data and insights from surveillance, disease testing, and mosquito control at every lifecycle stage—all supported by robust public education initiatives—to stay ahead of mosquito-borne disease threats. 

Whether you need full program management or expert support, VDCI has the technical expertise to partner with local leaders and jurisdictions. Contact our mosquito management experts today to help curb the spread of mosquito-borne diseases in 2026.

SOURCES

1. U.S. Centers for Disease Control and Prevention (CDC). https://www.cdc.gov/ 

VDCI Wants To Make Your Community Safer. How Can We Help?

Speak to an expert about implementing an IMM program.

Fill out the information below, and one of our experts will follow up with you shortly.

VDCI_Logo_squareSince 1992, Vector Disease Control International (VDCI) has taken pride in providing municipalities, mosquito abatement districts, industrial sites, planned communities, homeowners associations, and golf courses with the tools they need to run effective mosquito control programs. We are determined to protect the public health of the communities in which we operate. Our mosquito control professionals have over 100 years of combined experience in the field of public health, specifically vector disease control. We strive to provide the most effective and scientifically sound mosquito surveillance and control programs possible based on an Integrated Mosquito Management approach recommended by the American Mosquito Control Association (AMCA) and Centers for Disease Control and Prevention (CDC). VDCI is the only company in the country that can manage all aspects of an integrated mosquito management program, from surveillance to disease testing to aerial application in emergency situations.

The Battle Against Mosquitoes: What Does “Winning” Look Like?

larviciding-plane-in-air-applying-aerial-treatment

Mosquitoes Are Here to Stay—So What Does Success Look Like?

Mosquitoes have existed for over 100 million years, surviving through the Jurassic Period, the Ice Age, and numerous environmental extremes thanks to their remarkable adaptability. While it’s appealing to imagine a world free from itchy mosquito bites, completely eliminating mosquitoes is an unrealistic goal. “Winning” the battle isn’t about eliminating all mosquitoes; it’s about protecting public health by reducing the mosquito population to a manageable level, thereby reducing the spread of vector-borne diseases. Historical precedent suggests this is only possible through a coordinated, integrated management approach.

Ancient Mosquito Preserved in Amber

A Historic Example of Targeted Mosquito Control

For example, in the 1950s, Anopheles gambiae, a vector of malaria, was accidentally imported from Africa to Brazil, leading to thousands of deaths. In response, Brazil launched a highly organized campaign to eliminate this invasive species. This involved daily surveys, mapping infestations, and suffocating larvae by applying oil to their preferred breeding sites—puddles, irrigated fields, and even water that collected in cattle hoof prints. Because Anopheles gambiae feeds exclusively on humans and stays close to its breeding areas, teams could systematically move from the outskirts of communities inward. This approach successfully eliminated the Anopheles gambiae from Brazil and stands as one of the most historically successful mosquito elimination programs ever instituted.

Why Short-Term Mosquito Management Programs Fall Short

Similar strategies were used in the United States in the 1960s to control Aedes aegypti, the primary vector of yellow fever. Programs combined careful monitoring, habitat management, and door-to-door community education. Residents were encouraged to eliminate standing water from buckets, tires, birdbaths, and other small containers that serve as Aedes aegypti breeding grounds. These efforts temporarily reduced their populations to near-zero numbers in some areas. Unfortunately, when the program ended in the early 1970s due to funding and commitment challenges, this mosquito species rebounded in full force.

Clsoe-up-mosquito
dumping-standing-water

These examples illustrate that mosquito population dynamics are always evolving, particularly due to increased global trade, travel,  insecticide resistance, and climate change, which are creating new areas and conditions for mosquitoes to spread. Today’s mosquito management programs build on the lessons and successes of past initiatives. They are scientifically precise, carefully tailored, and designed to achieve maximum impact while minimizing environmental effects. 

Targeting Mosquitoes at Every Life Stage

VDCI’s Integrated Mosquito Management (IMM) programs are defined by four pillars: surveillance and disease testing, larval control, adult control, and public education. By leveraging the latest technologies and targeting mosquitoes at every stage of their life cycle, these programs can help reduce mosquito populations and the risk of disease transmission. Nonetheless, true success depends on the support and cooperation of the local community, particularly in removing standing water where many urban mosquitoes breed.

4 pillars of integrated mosquito management plans infographic

The Cost of Letting Mosquito Control Lapse

Historical examples prove that when mosquito management is prioritized, populations can be effectively managed. However, they also demonstrate that if efforts lapse due to funding gaps, political changes, or public disengagement, decades of progress can be quickly reversed. Government leaders and public health officials must recognize that the battle against mosquitoes can never be truly won. It is a continuous effort that requires a sustained investment in time, resources, and community education.

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Contact Our Experts

Complete the form below or call us at 800-413-4445 to speak to an expert about your mosquito management needs.

VDCI_Logo_squareSince 1992, Vector Disease Control International (VDCI) has taken pride in providing municipalities, mosquito abatement districts, industrial sites, planned communities, homeowners associations, and golf courses with the tools they need to run effective mosquito control programs. We are determined to protect the public health of the communities in which we operate. Our mosquito control professionals have over 100 years of combined experience in the field of public health, specifically vector disease control. We strive to provide the most effective and scientifically sound mosquito surveillance and control programs possible based on an Integrated Mosquito Management approach recommended by the American Mosquito Control Association (AMCA) and Centers for Disease Control and Prevention (CDC). VDCI is the only company in the country that can manage all aspects of an integrated mosquito management program, from surveillance to disease testing to aerial application in emergency situations.

5 Ways to Educate Citizens on Mosquito Bite Prevention

vdci-handing-to-public (2)

Keeping Communities Safe Through Public Education

While mosquitoes are among some of the smallest animals in the world, they have an enormous impact on our enjoyment and safety when outdoors. Most people don’t anticipate contracting a disease while cheering at a sporting event, relaxing by a firepit, or enjoying an afternoon picnic. Yet, these outdoor activities leave us vulnerable to pesky bites as well as dangerous diseases such as West Nile virus, Eastern equine encephalitis, yellow fever, and dengue.

Protecting the public from nuisance mosquitoes and mosquito-borne diseases requires awareness of bite prevention strategies and best practices to limit mosquito reproduction. Integrated Mosquito Management (IMM) programs play a key role in minimizing public health threats, and public education is the backbone of their success. Here are 5 unique ways to educate members of your community:

Leverage social media

Social media platforms are powerful tools for reaching diverse audiences quickly. Sharing visually engaging posts with tips on preventing mosquito bites, such as avoiding the outdoors at times of peak mosquito activity (dawn and dusk), wearing long sleeves and pants when outside, and applying mosquito repellents containing 10-30% DEET (N,N Diethyl-meta-toluamide). Infographics, videos, and short-form content can help break down and make complex information easily accessible. Encouraging followers to share posts can help expand the reach of educational materials.

Host city-wide events

vdci-booth-public-education

Community events are excellent opportunities to engage the public in removing breeding mosquito sites. For example, organizing disposal days for tires—which often collect water during rainfall—can help reduce the availability of standing water that many species need to lay their eggs. Setting up booths at farmers markets or hosting informational sessions at local libraries are also effective ways to connect with community members, answer questions, and distribute educational materials and free mosquito repellent.

Use QR codes

Strategically placing signs in parks, residential areas, and public spaces can help draw attention and encourage learning. QR codes make accessing videos, guides, or other educational resources quick and easy. Signs can also highlight quick facts about common sites where mosquitoes breed and best practices for personal protection against their bites.

Visit schools

Most kids have experienced pesky mosquito bites, but may not understand how to prevent them. Consider visiting schools to teach children about mosquito prevention through interactive presentations or hands–on activities. Simple lessons like recognizing mosquito breeding habitats and effective ways to protect themselves against bites can help instill good habits and share their newfound knowledge at home. 

Go door-to-door

vdci-handing-to-public (2)

Going door-to-door allows for more personalized interactions with community members. Helping homeowners identify specific areas on their properties where water accumulates, such as gutters, bird baths, pet bowls, plant saucers, buckets, and tarps, can help encourage best practices. Magnets or brochures can serve as reminders to keep this knowledge top of mind in the future.

Public education is a vital cornerstone of effective mosquito prevention. By using a variety of outreach strategies, you can ensure community members of all ages and backgrounds are equipped with the knowledge they need to protect themselves and inhibit the spread of mosquito-borne diseases. 

Contact Our Experts

Complete the form below or call us at 800-413-4445 to speak to an expert about your mosquito management needs.

VDCI_Logo_squareSince 1992, Vector Disease Control International (VDCI) has taken pride in providing municipalities, mosquito abatement districts, industrial sites, planned communities, homeowners associations, and golf courses with the tools they need to run effective mosquito control programs. We are determined to protect the public health of the communities in which we operate. Our mosquito control professionals have over 100 years of combined experience in the field of public health, specifically vector disease control. We strive to provide the most effective and scientifically sound mosquito surveillance and control programs possible based on an Integrated Mosquito Management approach recommended by the American Mosquito Control Association (AMCA) and Centers for Disease Control and Prevention (CDC). VDCI is the only company in the country that can manage all aspects of an integrated mosquito management program, from surveillance to disease testing to aerial application in emergency situations.

2024 Mosquito-Borne Disease Year In Review

West-Nile-Virus-UK-spread-Europe-outbreak-1001738

Exploring the Impact of Mosquito-Borne Diseases In 2024

In 2024, the U.S. was impacted by 27 individual weather and climate disasters—the second most on record, behind 28 disasters in 2023¹. Climate change appears to be increasing the frequency, intensity, and regional impact of hurricanes, storms, and heat waves. These events, in addition to other human-caused activities like deforestation, not only foster environments that enable mosquitoes to transmit diseases but also drive mosquito populations into regions that were once less hospitable or affected by certain vector-borne diseases.

This year-in-review examines six of the most widespread mosquito-borne diseases in the U.S., comparing five years of historical data compiled by the U.S. Centers for Disease Control and Prevention (CDC)². While some diseases such as St. Louis Encephalitis saw a decrease in cases, others like Eastern Equine Encephalitis (EEE) rose sharply. EEE made several headlines this past year when an increase in cases was reported in New England, specifically New Hampshire and Massachusetts. Not to mention an increase in dengue outbreaks in North, Central, and South America and the Caribbean which lead to a spike in travel-associated and locally acquired cases in the U.S. These insights can help shape your mosquito management plans and public education initiatives for the year ahead.  

*At the time of publishing this information, mosquito-borne disease-related deaths have not been reported by the CDC. Please note, the CDC counts the District of Columbia as a state

West Nile Virus

West Nile virus (WNv) remains the most deadly mosquito-borne illness in the continental U.S. Since its initial detection in 1999, it has become endemic (regularly occurring) in most regions. Although WNv cases significantly declined in 2024 compared to the previous year, the virus remains widespread—reported in every state except Alaska and Oregon. Of the 1,466 cases, more than 72% were classified as neuroinvasive.

Symptoms

While healthy individuals may not notice symptoms, they can range from mild flu-like symptoms such as fevers, headaches, or neck stiffness to severe neurological conditions such as meningitis and encephalitis (brain inflammation), particularly among older populations or those with compromised immune systems. Approximately 5-10% of cases are fatal.

Primary vectors 

WNv is most commonly transmitted by mosquitoes from the genera Culex, including Culex pipiens, Culex tarsalis, and Culex quinquefasciatus. Birds also play a notable role in the spread of the virus. When a mosquito bites an infected bird, it can contract the virus and become a carrier. The mosquito can then transmit the virus to humans through later bites.

Year-Over-Year Change in West Nile Virus Cases

2024
1,466 cases (1,063 neuroinvasive)
2023
2,406 cases (1,599 neuroinvasive)
2022
1,132 cases (827 neuroinvasive)
2021
2,911 cases (2,008 neuroinvasive)
2020
731 cases (559 neuroinvasive)

Top 5 states for West Nile Virus Human Case Count

2024 West Nile Virus Human Cases In the U.S.
Image Source: U.S. Centers for Disease Control and Prevention https://www.cdc.gov/west-nile-virus/data-maps/current-year-data.html
Cases
0
Neuroinvasive Cases
0
States Reporting Human Cases
0

Dengue

Dengue consists of four distinct viruses, referred to as dengue 1, 2, 3, and 4. It is most prevalent in tropical and subtropical regions. In 2024, over 12 million cases of dengue were reported in North, Central, and South America and the Caribbean. These outbreaks led to a major spike in travel-associated infections in the United States. Last year, the CDC reported 9,255 total cases, including both locally acquired and travel-associated infections. Combined, these cases spanned 53 U.S. jurisdictions, though local transmission occurred in only three states, California, Florida, and Texas.

Symptoms

Dengue symptoms can vary from mild joint pain, headaches, and fever to severe hemorrhagic fever, which can cause blood vessel damage. Contracting the virus a second time greatly increases the risk of severe illness, particularly in young children and older adults. Approximately 1% of cases are fatal.

Primary vectors 

Dengue is most often spread to humans by Aedes genus mosquitoes, particularly Aedes aegypti and Aedes albopictus. Additionally, the virus can be transmitted to fetuses during pregnancy.

Year-Over-Year Change in Dengue Cases

2024
6,076 locally acquired cases (3,179 travel-related)
2023
1,104 locally acquired cases (1,452 travel-related)
2022
1,044 locally acquired cases (1,494 travel-related)
2021
609 locally acquired cases (205 travel-related)
2020
983 locally acquired cases (354 travel-related)

Top 5 states for Dengue Human Case Count

2024 Dengue Human Cases In the U.S.
Dengue​ cdc map 2024
Image Source: U.S. Centers for Disease Control and Prevention, Accessed on January 1, 2025 https://www.cdc.gov/dengue/data-research/facts-stats/current-data.html
Locally Acquired Cases
0
Travel-associated Cases
0
States Reporting Locally Acquired Human Cases
0

Eastern Equine Encephalitis

Eastern Equine Encephalitis (EEE) is a rare but potentially deadly mosquito-borne disease primarily found in Northeast, Mid-Atlantic, and Gulf Coast states. In 2024, EEE made several headlines with reports reaching a five-year high with 19 confirmed cases—the third-highest count since 2005. 

Symptoms

Symptoms include high fever, headache, brain inflammation, seizures, and paralysis. Severe cases are most likely to occur among children and older populations. Approximately 30% of cases are fatal, but evidence suggests survivors develop lifelong immunity to the virus. Horses, pigs, rodents, and some deer species are also susceptible to the disease. 

Primary vectors 

EEE primarily circulates between birds and the primary mosquito vector species, Culiseta melanura. However, transmission to humans and animals occurs through mosquitoes from the Aedes, Coquillettidia, and Culex genera, which feed on infected birds before biting mammals.

Year-Over-Year Change in Eastern Equine Encephalitis Cases

2024
19 cases (19 neuroinvasive)
2023
7 cases (7 neuroinvasive)
2022
1 case (1 neuroinvasive)
2021
5 cases (5 neuroinvasive)
2020
13 cases (13 neuroinvasive)

Top 5 states for Eastern Equine Encephalitis Human Case Count

2024 Eastern Equine Encephalitis Human Cases Reported In the U.S.
Image Source: U.S. Centers for Disease Control and Prevention, Accessed on January 1, 205 https://www.cdc.gov/eastern-equine-encephalitis/data-maps/current-year-data.html
Cases
0
Neuroinvasive Cases
0
States Reporting Human Cases
0

La Crosse Encephalitis

In 2024, La Crosse Encephalitis cases continued their upward trend, with most reports coming from North Carolina and Tennessee. Nearly all reported infections progressed to neuroinvasive disease.

Symptoms

This mosquito-borne disease primarily impacts children, causing symptoms like fever, headache, and nausea. In neuroinvasive cases, it can lead to severe complications such as seizures, disorientation, vision loss, and other serious issues. Approximately 1% of cases are fatal.

Primary vectors 

The La Crosse virus is transmitted through the bite of an infected Aedes triseriatus, commonly known as the Eastern treehole mosquito.

Year-Over-Year Change in La Crosse Encephalitis​ Cases

2024
35 cases (34 neuroinvasive)
2023
31 cases (30 neuroinvasive)
2022
22 cases (19 neuroinvasive)
2021
40 cases (39 neuroinvasive)
2020
88 cases (84 neuroinvasive)

Top 3 states for La Crosse Encephalitis Human Case Count

2024 La Crosse Encephalitis Human Cases In the U.S.
Image Source: U.S. Centers for Disease Control and Prevention, Accessed on January 1, 2025 https://www.cdc.gov/la-crosse-encephalitis/data-maps/current-year-data.html
Cases
0
Neuroinvasive Cases
0
States Reporting Human Cases
0

St. Louis Encephalitis

The St. Louis encephalitis virus was first identified in 1933 during an epidemic in St. Louis, Missouri, which led to over 1,000 cases of encephalitis. In 2024, St. Louis Encephalitis cases saw a dramatic decline, with only one reported case in South Carolina—the lowest case count since 2013 when just a single case was also recorded.

Symptoms

Common symptoms include fever, headache, and confusion, with severity often increasing with age. On average, 90% of infected older adults develop brain inflammation. The fatality rate ranges from 3% to 30%.

Primary vectors 

The main mosquito vectors for the virus are Culex pipiens, Culex quinquefasciatus, Culex tarsalis, and Culex nigripalpus. Wild birds, such as blue jays, sparrows, robins, and pigeons serve as amplifying hosts. 

Year-Over-Year Change in St. Louis Encephalitis​ Cases

2024
1 case (0 neuroinvasive)
2023
19 cases (13 neuroinvasive)
2022
33 cases (27 neuroinvasive)
2021
17 cases (11 neuroinvasive)
2020
16 cases (14 neuroinvasive)

Top states for St. Louis Encephalitis Human Case Count

2024 St. Louis Encephalitis Human Cases In the U.S.
Image Source: U.S. Centers for Disease Control and Prevention, Accessed on January 24, 2024 https://www.cdc.gov/sle/data-maps/current-year-data.html
Case
0
Neuroinvasive Cases
0
States Reporting Human Cases
0

Jamestown Canyon virus

In 2024, the number of Jamestown Canyon virus cases remained consistent with the previous year, with 22 reported cases—15 of which became neuroinvasive. The majority of cases were concentrated in the Great Lakes region. Historically, more than half of all cases have been reported in Wisconsin and Minnesota.

Symptoms

Many people infected with Jamestown Canyon virus do not have symptoms. Those who do may experience fever, headache, muscle soreness, and respiratory issues. Severe infections can lead to disorientation, seizures, and other neurological complications.

Primary vectors 

The virus can be spread by different mosquito species, with deer often serving as the amplifying host. Humans are deemed “dead-end” hosts for the virus, as their blood lacks the virus levels necessary to infect mosquitoes and propagate the disease further.

Year-Over-Year Change in Jamestown Canyon Virus Cases

2024
22 cases (15 neuroinvasive)
2023
21 cases (15 neuroinvasive)
2022
12 cases (11 neuroinvasive)
2021
32 cases (21 neuroinvasive)
2020
13 cases (10 neuroinvasive)

Top 3 states for Jamestown Canyon Virus Human Case Count:

2024 Jamestown Canyon virus Human Cases Reported In the U.S.
jamestown
Image Source: U.S. Centers for Disease Control and Prevention, Accessed on January 24, 2025 https://www.cdc.gov/jamestown-canyon/data-maps/current-year-data.html
Locally Acquired Cases
0
Neuroinvasive Cases
0
States Reporting Human Cases
0

Utilizing Data to Drive Effective Integrated Mosquito Management Programs

The 2024 data underscore the growing threat of mosquito-borne diseases and the need for adaptive solutions and strategies, such as Integrated Mosquito Management (IMM) programs. IMM programs incorporate adult and larval mosquito control, surveillance and disease testing, and public education to stay ahead of evolving environmental challenges, reduce the risk of insecticide resistance, and keep our communities safe from vector-borne diseases. Through a proactive approach, we can build a strong foundation for long-term mosquito prevention and control.

SOURCES

1 NOAA National Centers for Environmental Information (NCEI) U.S. Billion-Dollar Weather and Climate Disasters (2025). https://www.ncei.noaa.gov/access/billions/ 

2 U.S. Centers for Disease Control and Prevention (CDC). https://www.cdc.gov/ 

VDCI Wants To Make Your Community Safer. How Can We Help?

Speak to an expert about implementing an IMM program.

Fill out the information below, and one of our experts will follow up with you shortly.

Since 1992, Vector Disease Control International (VDCI) has taken pride in providing municipalities, mosquito abatement districts, industrial sites, planned communities, homeowners associations, and golf courses with the tools they need to run effective mosquito control programs. We are determined to protect the public health of the communities in which we operate. Our mosquito control professionals have over 100 years of combined experience in the field of public health, specifically vector disease control. We strive to provide the most effective and scientifically sound mosquito surveillance and control programs possible based on an Integrated Mosquito Management approach recommended by the American Mosquito Control Association (AMCA) and Centers for Disease Control and Prevention (CDC). VDCI is the only company in the country that can manage all aspects of an integrated mosquito management program, from surveillance to disease testing to aerial application in emergency situations.

Reduce Mosquito-Borne Diseases with Disease Testing

Colleague-counting-mosquitos-close-up-oversholder

How Data Collection and Testing Help Reduce Mosquito-Borne Diseases

Mosquitoes are known to transmit several dangerous diseases that can pose a threat to human health. In the United States, mosquito-borne diseases such as West Nile virus, Eastern equine encephalitis virus, and dengue have all caused significant harm to communities nationwide – making the prevention of mosquito-borne diseases crucial for helping keep citizens safe. 

Proactively reducing the spread of these diseases starts with effective mosquito surveillance as part of an Integrated Mosquito Management (IMM) plan. Once adult mosquitoes are collected from various traps, they are sorted, identified, and analyzed in a lab where they undergo several tests, including disease testing. By testing adult mosquitoes for diseases, we can identify areas where disease-carrying mosquitoes are present and take appropriate action to reduce their population – ultimately reducing the spread of mosquito-borne diseases

VDCI lab testing vial mosquito control education

How Mosquito-Borne Disease Testing Works

Integrated Mosquito Management plans require extensive knowledge of mosquito species, breeding activities, and population dynamics to be successful. By conducting regular adult mosquito surveillance, experts can steadily monitor local populations, allowing us to detect mosquito-borne diseases weeks before they can be transmitted to humans or animals. Here’s how the disease testing process works:

  1. Our expert entomologists strategically set adult mosquito traps throughout a given area. Various mosquito traps are used depending on what information is desired. Each trap has its own unique advantages, many attract specific mosquito species, thereby focusing efforts to collect certain mosquito species that are more likely to carry disease. Traps are typically set weekly for regular population monitoring.

  2. Once a mosquito sample is collected, our entomologists will take them back to the lab for mosquito-borne disease testing.

  3. To identify which diseases are present in mosquito populations, our laboratory technicians will run PCR and RAMP® WNv tests. PCR tests allow us to detect different pathogens that are present inside the mosquito, while RAMP® tests are designed to detect West Nile virus, a commonly found mosquito-borne disease in the U.S.

  4. If a mosquito sample tests positive for any mosquito-borne diseases, our entomologists will report the results to all appropriate local and state health departments. With this data, experts can determine the severity of a disease outbreak and respond with effective mosquito management solutions. This often involves returning to the area where the sample was collected and employing adult and larval mosquito control efforts. 
surveillance and disease testing - lab testing - mosquito control - vdci - vector management - markets served

Testing Best Practices

Mosquito-borne disease testing is crucial for helping support effective and environmentally responsible mosquito control. It’s important to follow industry best practices when testing mosquitoes for diseases such as West Nile and malaria. 

  1. Test mosquitoes regularly to ensure we detect the presence of mosquito-borne diseases in a timely manner. 

  2. Test mosquitoes trapped in various parts of the community to ensure we are casting a wide net for mosquito surveillance in the whole community. 

  3. Use mosquito-borne disease testing results to drive IMM programs and reduce the spread of disease. 

When a mosquito pool tests positive for a disease, the results of these tests are immediately communicated to government and health officials. This allows decision-makers to act quickly to reduce the spread of mosquito-borne diseases within their communities. By following these best practices, we can arm public officials with the knowledge they need to make control decisions to reduce the spread of mosquito-borne diseases

Truck-spraying-treatment

Why Mosquito-Borne Disease Testing and Surveillance Matters

Mosquito-borne diseases can have severe consequences on the health and well-being of our communities nationwide. These diseases are transmitted through mosquito bites and can cause symptoms ranging from fever, rash, and neurological problems. Mosquito-borne disease testing and mosquito surveillance provide data and insights to drive a more effective IMM plan that works to reduce mosquito breeding sites and control both nuisance and disease-carrying mosquitoes.

A successful IMM program involves more than mosquito-borne disease testing. Several key pillars, including adult mosquito and larval surveillance, employing a variety of control strategies, and implementing public education within the community, are all part of a comprehensive program’s success. Citizens can help reduce the spread of mosquito-borne diseases by following the 4Ds: Defend, Dress, Drain, and Dusk & Dawn. Applying an EPA-approved mosquito repellent and wearing close-toe shoes, light-colored clothing, and long sleeves and pants while outdoors can significantly protect you from mosquito bites. Draining any standing water that could be a potential mosquito breeding site significantly reduces the mosquito population and the application of insecticides. In addition, limiting your outdoor exposure time, especially from dusk to dawn when mosquitos are most active, will lessen your chances of being bitten. When a comprehensive IMM program is established, it will protect public health and keep our communities safe. 

family playing on playground structure

Importance of Integrated Mosquito Management

Our scientific experts at VDCI have the experience, knowledge, and equipment required to implement a comprehensive IMM plan. A proactive approach to mosquito surveillance reduces mosquito-borne diseases and provides adequate time to respond to disease threats before becoming a serious issue to the public. With our industry-leading experts guiding mosquito management strategies in the communities we serve, you can rest assured that your citizens are protected.

Contact Our Experts

Complete the form below to speak to an expert about your community’s mosquito management needs.

VDCI_Logo_squareSince 1992, Vector Disease Control International (VDCI) has taken pride in providing municipalities, mosquito abatement districts, industrial sites, planned communities, homeowners associations, and golf courses with the tools they need to run effective mosquito control programs. We are determined to protect the public health of the communities in which we operate. Our mosquito control professionals have over 100 years of combined experience in the field of public health, specifically vector disease control. We strive to provide the most effective and scientifically sound mosquito surveillance and control programs possible based on an Integrated Mosquito Management approach recommended by the American Mosquito Control Association (AMCA) and Centers for Disease Control and Prevention (CDC). VDCI is the only company in the country that can manage all aspects of an integrated mosquito management program, from surveillance to disease testing to aerial application in emergency situations.

2023 Mosquito-Borne Disease Year In Review

West-Nile-Virus-UK-spread-Europe-outbreak-1001738

Exploring the Impact of Mosquito-Borne Diseases In 2023

In recent years, the United States has experienced an increase in the abundance and distribution of mosquito-borne diseases. The expansion of mosquito habitats, fueled by climate change, urban development, and other human-related factors poses considerable risks to public health. The need for increased vigilance and proactive strategies is clear in the 2023 data reported by the Centers for Disease Control (CDC) and Prevention, which indicates a resurgence of locally acquired malaria, a dramatic increase in West Nile virus cases, and shifts in the distribution of diseases like La Crosse encephalitis, Eastern equine encephalitis, dengue, Jamestown Canyon virus, and St. Louis encephalitis. In our 2023 review, we analyze the details of each disease, including case counts, notable trends, and the potential impact on public health.

*Please note, at the time of publishing this information, mosquito-borne disease-related deaths have not been reported by the CDC.

Malaria

While uncommon in the United States, 9 locally acquired malaria cases were reported across Florida (7 cases), Texas (1 case), and Maryland (1 case) during the summer of 2023. Though believed to be isolated events, the majority of these cases were caused by Plasmodium vivax, a protozoal parasite that infects the blood of its host and causes disease in humans.

Malaria can present with symptoms such as fever, chills, and flu-like illness. Severe cases may result in complications affecting the kidneys, lungs, and blood vessels. It is crucial to note that malaria can affect individuals of all ages, and prompt diagnosis is essential for effective treatment.

Typically, the United States records over 1,000 imported cases of malaria each year and zero locally acquired cases. According to the CDC, locally acquired mosquito-borne malaria has not been reported in the United States since 2003, when 8 cases were identified in Palm Beach County, FL. The main vector for malaria in the Eastern United States is Anopheles quadrimaculatus. The occurrence of 9 locally acquired malaria cases in 2023 serves as a reminder that mosquito dynamics are subject to change, and proactive measures are essential to address potential shifts in disease transmission patterns.

malaria distribution by country
Image Source: U.S. Centers for Disease Control and Prevention https://www.cdc.gov/parasites/malaria/index.html

West Nile virus

The frequency of West Nile virus infections reported in 2023 were more than double what we saw in 2022.  With torrential rains and flooding across many of the western states a total of 2,406 human disease cases were reported and many of those (n=1,599) experienced the most severe form of infection, including neuroinvasive symptoms. The top 5 states affected by this surge include  Colorado (626 cases), California (367 cases), Nebraska (150 cases), Illinois (113 cases), and South Dakota (93 cases). With 47 states reporting cases in 2023, compared to 43 in 2022, the virus continues to pose a widespread threat. 

Mosquitoes from the genera Culex are recognized as the primary vectors of the disease worldwide and in the U.S. Among these, Culex pipiens, Culex tarsalis, and Culex quinquefasciatus are the main species responsible for transmitting West Nile virus in the U.S. West Nile virus symptoms range from mild flu-like symptoms to severe neurological conditions. Older adults are particularly vulnerable to severe cases, experiencing complications such as meningitis and brain inflammation. 

Year Over Year Change

2023
2,406 cases (1,599 neuroinvasive)
2022
1,132 cases (827 neuroinvasive)
2021
2,911 cases (2,008 neuroinvasive)
2020
731 cases (559 neuroinvasive)

Top 5 states for Human Case Count:

2023 West Nile virus Cases In the U.S.
map-usa
Image Source: U.S. Centers for Disease Control and Prevention, Accessed on January 31, 2024 https://www.cdc.gov/westnile/statsmaps/current-season-data.html
2023 Human Case Count
0
2022 Human Case Count
0
States* reporting cases 2023
0
States* reporting cases 2022
0

*note: CDC counts District of Columbia as a state

La Crosse Encephalitis

La Crosse encephalitis witnessed an increase in human cases, with 31 reported in 2023, including 30 neuroinvasive cases. Ohio (12 cases), Tennessee (5 cases), and West Virginia (5 cases) led the 10 states that reported cases. 

This mosquito-borne disease primarily affects children and can lead to symptoms such as fever, headache, nausea, and, in severe cases, neuroinvasive complications. The transmission of the La Crosse virus occurs through the bite of an infected Aedes triseriatus, commonly known as the Eastern tree-hole mosquito.

Year Over Year Change​

2023
31 cases (30 neuroinvasive)
2022
22 cases (19 neuroinvasive)
2021
40 cases (39 neuroinvasive)
2020
88 cases (84 neuroinvasive)

Top 3 states for Human Case Count:​

2023 La Crosse Encephalitis Cases In the U.S.
map-usa
Image Source: U.S. Centers for Disease Control and Prevention, Accessed on January 31, 2024 https://www.cdc.gov/lac/statistics/current-season-data.html
2023 Human Case Count
0
2022 Human Case Count
0
States reporting cases 2023
0
States reporting cases 2022
0

Eastern Equine Encephalitis

Though there was only 1 case of Eastern Equine Encephalitis in 2022, 7 cases were reported by 4 states in 2023. All cases were neuroinvasive and occurred in the southeast – Alabama (3 cases), Florida (2 cases), Georgia (1 case), and Louisiana (1 case). 

While it primarily circulates between birds and the mosquito species Culiseta melanura, transmission to humans and animals can occur through mosquitoes of the Aedes, Coquillettidia, and Culex genera. These mosquitoes feed on infected birds and subsequently bite mammals, spreading the virus.

This disease poses a significant risk, especially among older adults and young children. Symptoms include high fever, headache, and, in severe cases, brain inflammation. The impact on vulnerable populations emphasizes targeted public health campaigns and mosquito control efforts.

Year Over Year Change​

2023
7 cases (7 neuroinvasive)
2022
1 case (1 neuroinvasive)
2021
5 cases (5 neuroinvasive)
2020
13 cases (13 neuroinvasive)

Top 4 states for Human Case Count:​

2023 Eastern Equine Encephalitis Cases In the U.S.
map-usa
Image Source: U.S. Centers for Disease Control and Prevention, Accessed on January 31, 2024 https://www.cdc.gov/easternequineencephalitis/statistics-maps/current-season-data.html
2023 Human Case Count
0
2022 Human Case Count
0
States reporting cases 2023
0
States reporting cases 2022
0

Jamestown Canyon Virus

Jamestown Canyon virus experienced a notable increase, with 21 human cases reported in 2023, 15 of which were neuroinvasive. Of the 7 states that reported cases, Wisconsin led with 9 human case counts, followed by Michigan (5 cases), Minnesota (2 cases), New Hampshire (2 cases), Illinois (1 case), New Jersey (1 case), and New York (1 case). 

The virus can be spread by different types of mosquitoes, with deer often serving as the amplifying host. Symptoms may include fever, headache, and neurological issues in severe cases. While not often fatal, the virus can cause long-term neurological complications. However, humans are deemed “dead-end” hosts for the virus, as their blood lacks the virus levels necessary to infect mosquitoes and propagate the disease further.

Year Over Year Change​

2023
21 cases (15 neuroinvasive)
2022
12 cases (11 neuroinvasive)
2021
32 cases (21 neuroinvasive)
2020
13 cases (10 neuroinvasive)

Top 4 states for Human Case Count:​

2023 Jamestown Canyon Virus Cases In the U.S.
map-usa
Image Source: U.S. Centers for Disease Control and Prevention, Accessed on January 31, 2024 https://www.cdc.gov/jamestown-canyon/statistics/current-season-data.html
2023 Human Case Count
0
2022 Human Case Count
0
States reporting cases 2023
0
States reporting cases 2022
0

St. Louis Encephalitis

St. Louis encephalitis reported 19 cases in 2023 (13 neuroinvasive), a notable decrease from 2022. Of the 3 reporting states, California recorded the highest number (17 cases), followed by South Carolina (1 case) and Washington (1 case). 

Culex pipiens, Culex quinquefasciatus, Culex tarsalis, and Culex nigripalpus are the predominant mosquito vectors. Wild birds are amplifying hosts, yet typically remain asymptomatic.

This disease primarily affects older adults and can result in symptoms such as fever, headache, and confusion. The severity of symptoms typically increases with age. Approximately 90% of elderly people who become infected with this virus develop brain inflammation, according to the CDC. The fatality rate for cases ranges between 5% and 20%.

Year Over Year Change​

2023
19 cases (13 neuroinvasive)
2022
33 cases (27 neuroinvasive)
2021
17 cases (11 neuroinvasive)
2020
16 cases (14 neuroinvasive)

Top 3 states for Human Case Count:​

2023 St. Louis Encephalitis Cases In the U.S.
2023 Human Case Count
0
2022 Human Case Count
0
States reporting cases 2023
0
States reporting cases 2022
0
map-usa
Image Source: U.S. Centers for Disease Control and Prevention, Accessed on January 31, 2024 https://www.cdc.gov/sle/statistics/current-season-data.html

Dengue

Dengue comprises a group of viruses transmitted to humans through infected mosquitoes of the Aedes genus, specifically Aedes aegypti and Aedes albopictus. Though showing a slight overall decrease, Dengue still poses a considerable public health concern with 2,556 reported cases in 2023. More than half of the cases were travel-associated, but 1,104 were locally acquired. Puerto Rico and Florida emerged as the top jurisdictions reporting locally acquired cases.

Dengue symptoms range from mild fever to severe hemorrhagic fever. Severe cases are more common in young children and older adults. Transmission of the disease to a fetus can also occur during pregnancy.

Year Over Year Change​

2023
1,104 cases
1,452 cases
2022
1,044 cases
1,494 cases
2021
609 cases
205 cases
2020
983 cases
354 cases

*Red= Locally Acquired Cases, Grey= Travel Related Cases

Top 4 states for Human Case Count:​

2023 Dengue Cases In the U.S.
map-usa
Image Source: U.S. Centers for Disease Control and Prevention, Accessed on January 31, 2024 https://www.cdc.gov/dengue/statistics-maps/current-data.html
2023 Human Case Count
0
2022 Human Case Count
0
States reporting cases 2023
0
States reporting cases 2022
0

Utilizing Data to Drive Informative Mosquito Management Programs

The 2023 data highlights the evolving regional dynamics of mosquito-borne diseases and underscores the importance of tailored, localized efforts to limit the spread. Adult mosquito management,  surveillance, disease testing, and public education are pivotal in safeguarding the health of our nationwide communities. Integrated Mosquito Management programs incorporate these key strategies and provide a science-based approach to mosquito control. As we navigate the evolving landscape of mosquito-borne diseases, proactive measures and a collective commitment to public health remain our most impactful tools to combat these growing threats.

Other Noteable Data

  • Locally acquired malaria found in U.S. for first time in 20 years (2003, 8 cases in Florida)
  • West Nile virus case count more than doubles from 2022 (105.65% increase)
  • La Crosse (31% 🔼) , Eastern Equine (600% 🔼), and Jamestown Canyon (66.66% 🔼) all see human case count increases.
  • Dengue human case count decreases slightly (🔽 -7.6%)

VDCI Wants To Make Your Community Safer. How Can We Help?

Speak to an expert about implementing an IMM program.

Fill out the information below, and one of our experts will follow up with you shortly.

Since 1992, Vector Disease Control International (VDCI) has taken pride in providing municipalities, mosquito abatement districts, industrial sites, planned communities, homeowners associations, and golf courses with the tools they need to run effective mosquito control programs. We are determined to protect the public health of the communities in which we operate. Our mosquito control professionals have over 100 years of combined experience in the field of public health, specifically vector disease control. We strive to provide the most effective and scientifically sound mosquito surveillance and control programs possible based on an Integrated Mosquito Management approach recommended by the American Mosquito Control Association (AMCA) and Centers for Disease Control and Prevention (CDC). VDCI is the only company in the country that can manage all aspects of an integrated mosquito management program, from surveillance to disease testing to aerial application in emergency situations.

Understanding the Mosquito Life Cycle

mosquito biting skin

What are the life stages of a mosquito?

Understanding the developmental processes of mosquitoes is crucial to keeping them under control. While there are thousands of different mosquito species, they all undergo complete metamorphosis. This means they have a lifecycle which includes four distinct growth stages: egg, larva, pupa, and adult.

Watch the video below to learn more about the process. 

A Deep Dive Into the Mosquito Life Cycle

Most female mosquitoes lay their eggs in or near water, just above the water line, or moist soil in areas that are prone to flooding. Most mosquitoes can be categorized as floodwater, permanent water, or container species based on the types of habitats utilized for larval development. 

Where Do Mosquitoes Lay Their Eggs?

Floodwater

Floodwater mosquitoes lay eggs in low-lying areas that temporarily fill with water, such as ditches, agricultural lands, or dry basins. These eggs will hatch when they become submersed during rainfall or flooding events.

Permanent

Permanent water species lay their eggs on standing waterbodies like ponds and marshes. 

Container

Container species lay their eggs on the edge of small stagnant water vessels, such as bird baths, buckets, and even bottle caps. 

What are the life stages of a mosquito?

The Larval Stage

Once exposed to water, larvae will typically hatch from their eggs within 48 hours. During this stage, most larvae suspend themselves near the surface, breathing through a siphon-like tube, and feeding on organic matter and microorganisms. 

mosquito life cycle

The Pupal Stage

Over the course of approximately 4 to 14 days, larvae will shed their skin, or molt, 4 times before developing as pupae

Pupae continue to develop near the surface, resembling small, squirming commas. 

The Adult Stage

After two to four days, adult mosquitoes emerge from their pupal exoskeletons and exit the water as adults. Blood meals are essential for some mosquito species, and it is important to note that only the females seek blood-meals, which provide the nutrition necessary to support egg development.

Though male mosquitoes typically die within five to seven days, females can live several months and are capable of laying thousands of eggs. During this time, many species are capable of vectoring dangerous diseases like West Nile Virus, Yellow Fever, Zika, Dengue, and Eastern Equine Encephalitis.

Our understanding of the diversity of mosquito species and their unique life cycles is instrumental in developing effective management strategies to maintain safer, more enjoyable outdoor spaces.

VDCI_Logo_squareSince 1992, Vector Disease Control International (VDCI) has taken pride in providing municipalities, mosquito abatement districts, industrial sites, planned communities, homeowners associations, and golf courses with the tools they need to run effective mosquito control programs. We are determined to protect the public health of the communities in which we operate. Our mosquito control professionals have over 100 years of combined experience in the field of public health, specifically vector disease control. We strive to provide the most effective and scientifically sound mosquito surveillance and control programs possible based on an Integrated Mosquito Management approach recommended by the American Mosquito Control Association (AMCA) and Centers for Disease Control and Prevention (CDC). VDCI is the only company in the country that can manage all aspects of an integrated mosquito management program, from surveillance to disease testing to aerial application in emergency situations.

Contact Us to Build Your Mosquito Management Program:

Effects of Mosquito-Borne Diseases on Bird Populations

bird on tree branch

How Mosquitoes Impact Bird Populations and Our Ecosystem

Imagine walking through the streets of New York City on a hot August day and seeing dead crows distributed across large areas. This is a real-world event that occurred in 1999. Scientists did not understand the reason for the sudden deaths among crow populations, but later discovered their brains and organs suffered severe bleeding. Soon after, they identified a correlation between the abrupt crow deaths and unexplained neurological symptoms afflicting human several patients at a local hospital. Both the crows and sick patients contracted a disease that had never before been detected in the United States – West Nile virus (WNv).

Crows-sitting-on-tree

How Mosquito and Bird Interaction Amplifies West Nile Virus

The delicate balance of ecosystems relies on a complex web of interactions between species. Among them, the relationship between birds and mosquitoes is often overlooked. The mosquito species Culex pipiens was determined to be the most likely source of the virus. Though this species had been in the country well before 1999, new Culex pipiens mosquitoes may have carried the disease over through global travel or the trade of goods like exotic plants. WNv could also have been brought into the United States by migratory birds and then transmitted by local Culex pipiens mosquitoes. WNv has a complicated life cycle, requiring amplification in birds before being transmitted to people. For a person to become infected, they must be bitten by a mosquito that has previously fed upon an infected bird.

Birds and Mosquito-Borne Diseases

Clsoe-up-mosquito

In addition to WNv, birds are susceptible to several of the same mosquito-borne diseases that impact humans, including Eastern Equine Encephalitis and St. Louis Encephalitis. Through their diverse interactions and migratory behaviors, birds can spread diseases rapidly among their populations, including other bird species. In fact, more than 300 bird species across the globe can become infected through mosquito bites or by consuming infected mosquitoes or other sick birds.

The Spread of West Nile Virus in the U.S.

Since being introduced in 1999, WNv infection has become the most common mosquito-borne illness in the United States, with human and non-human cases reported in almost every state. Though most people who contract the virus do not display symptoms, more severe cases can cause flu-like symptoms, neurological problems, and death. Because only a small number of WNv cases are reported, the Centers for Disease Control estimates that the actual number of illnesses may be two to three times higher than reported. Most cases occur during the summer, reaching their highest numbers in early autumn. Around 25 mammal species and at least 2 reptile species have been identified as hosts to the virus.

Advancements in Understanding and Controlling West Nile Virus

Luckily, scientists have learned significantly more about WNv since 1999. We now know it can be carried by more than 150 mosquito species, but Culex pipiens, Culex tarsalis, and Culex quinquefasciatus remain the primary WNv vectors. Many government agencies have established surveillance programs to monitor the spread of mosquito-borne diseases among bird populations. These efforts go hand-in-hand with the proactive efforts conducted via Integrated Mosquito Management programs, which include surveillance and data collection through trapping and disease testing, as well as the application of EPA-registered larvicides and adulticides when mosquito control measures are required.

The Role of Public Education and Prevention

vdci-education-public

Public education is also paramount in detecting diseases early on, so swift action can be taken to preserve public health. Sightings of dead birds should be reported to local wildlife agencies. Homeowners can eliminate the habitats where Culex pipiens mosquitoes tend to develop by eliminating standing water around their properties. Flowerpot saucers, outdoor pet bowls, buckets, bird baths, and clogged gutters are common sources of standing water. Education about personal protection is also essential. Community members can reduce their risk of infection by applying EPA-registered insect repellents, wearing pants and long sleeves, and avoiding the outdoors around dawn and dusk, the hours of peak mosquito activity.

The event of 1999 is a stark example of the devastating impact mosquitoes can have on bird populations, local ecosystems, and the public. It’s crucial to stay ahead of disease transmission through continuous monitoring, research, and public education. Contact the mosquito management experts today to start designing your Integrated Mosquito Management program.

Contact Us to Build Your Mosquito Management Program:

VDCI_Logo_squareSince 1992, Vector Disease Control International (VDCI) has taken pride in providing municipalities, mosquito abatement districts, industrial sites, planned communities, homeowners associations, and golf courses with the tools they need to run effective mosquito control programs. We are determined to protect the public health of the communities in which we operate. Our mosquito control professionals have over 100 years of combined experience in the field of public health, specifically vector disease control. We strive to provide the most effective and scientifically sound mosquito surveillance and control programs possible based on an Integrated Mosquito Management approach recommended by the American Mosquito Control Association (AMCA) and Centers for Disease Control and Prevention (CDC). VDCI is the only company in the country that can manage all aspects of an integrated mosquito management program, from surveillance to disease testing to aerial application in emergency situations.

Using Your Smartphone to Help Monitor Mosquito Activity

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As warm weather begins to take hold across North America, many people are itching to get outside and enjoy more seasonal temperatures. However, in the wake of a very wet winter and spring in many parts of the United States, scientists are already raising the red flag about heightened mosquito activity in 2023. 

As the climate continues to change, new mosquito species are becoming more prevalent in the United States, particularly in more tropical areas of the country, like Florida and the Gulf Coast states. For example, in March 2023, new research by Larry Reeves from the University of Florida’s Institute of Food and Agricultural Science published in the Journal of Medical Entomology reported on Culex lactator, a mosquito species from South America that is slowly gaining a foothold in Florida. Understanding how fast new species like this are spreading, where they are being found, and how they adapt to new climates is critical to developing control methods. 

With the rapid evolution of technology, mosquito researchers are now looking toward ordinary citizens to help gain some of this knowledge, elevating “citizen science” to a new level in helping to understand mosquito activity around the globe. Two new apps, available to anyone using a smartphone or web-enabled tablet, are now making it easier for scientists to track and understand mosquito activity with the help of citizens interested in protecting public health from mosquitoes. 

What is citizen science?

The term “citizen science” was first coined in 1989 by researchers at the Massachusetts Institute of Technology (MIT) in describing work being done by community members who were interested in environmental issues. 

The Cambridge Dictionary defines citizen science as “scientific work, for example collecting information, that is done by ordinary people without special qualifications, in order to help the work of scientists.” 

By this definition, any of us can help enable mosquito research from our communities and even our backyards if we know what to look for and how to report it. That’s where two easily downloadable applications, the Globe Observer app and the Mosquito Alert app, empower everyday citizens to help inform scientists about mosquito activity with just a few taps on their smart devices. 

Mosquito Research Safety Precautions

Before using either of the apps in this article, it is important to note that voluntarily engaging in any mosquito research activity can increase your likelihood of being bitten by mosquitoes, which can spread diseases that are harmful to humans and our pets, such as West Nile virus, heartworm, Eastern equine encephalitis (EEE), dengue, and more. 

As such, it is important to take safety precautions if you plan to be outside or in any area where mosquitoes are known to be active. Remember the 4Ds to help reduce your chances of being bitten. 

  • DEFEND – Always protect yourself by using a U.S. Environmental Protection Agency (EPA)-registered insect repellent
  • DRESS – Dress in closed-toe shoes and loose-fitting pants and long-sleeve shirts that are light in color. Avoid wearing perfumes or other scented products that may attract mosquitoes. 
  • DRAIN – Remove or drain any standing water. 
  • DAWN AND DUSK – Avoid the outdoors during dawn and dusk hours when mosquitoes are most active.

The Globe Observer App

Powered by the United States National Aeronautic and Space Administration (NASA), the Globe Observer app enables users to enter data and information in 4 different areas: clouds, land cover, trees, and the mosquito habitat mapper. For this blog, we’ll focus on the latter area. 

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To best use the Globe Observer app, users will need to do the following:

  • Download the app to your smart device.
  • Create an account using their email address and verify through a password emailed to the supplied email address.
  • Enable location services while using the app; this allows for the app to easily help you report mosquito breeding habitats.
  • Take photos using your smart device.
  • Allow access to your device’s camera for uploading photos of habitats and larvae.

For safety purposes, this app focuses users on recording data related to mosquito breeding sites and larvae rather than tracking adult mosquitoes.

Once users have downloaded the app and created their account, they can use the mosquito habitat mapper to take one of four actions:

  1. Identify potential mosquito habitats
  2. Sample and count mosquito larvae (using a cup, bulb syringe, or other container)
  3. Identify the larva type (may require a microscope or macro lens on your device’s camera)
  4. Eliminate the larva you have counted and the breeding habitat, if possible

Each of these actions can be taken with a few simple taps, by following the directions provided on each screen.

Users can also view maps of the mosquito observations that other users have made by clicking on the chart icon at the bottom left corner of the screen from anywhere in the app and selecting the See Today’s Mosquito Measurements button. The feature works best when you view it over a cumulative time period. Users can leverage the calendar and zoom features to see further details of activity recorded by other citizen scientists. 

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The Mosquito Alert App

A public information project coordinated by four different research organizations, the Mosquito Alert app works similarly to the Globe Observer app to help citizens report a variety of different mosquito-related conditions to help monitor activity in their area. Data for this citizen science project has been recorded since 2014. 

The Mosquito Alert app is based internationally in Spain, developed by the Centre for Ecological Research and Forestry Applications (CREAF), Pompeu Fabra University (UPF), Catalan Institution for Research and Advanced Studies (ICREA), and Blanes Center for Advanced Studies (CEAB-CSIC). As such, many of the current users of the app are based in Europe, but the activity maps do reflect some reports in the Americas. 

To best use the Mosquito Alert app, users will need to:

  • Download the app to your smart device.
  • Create an account.
  • Enable location services while using the app for mapping purposes.
  • Take photos using your smart device.
  • Allow access to your device’s camera for uploading photos of mosquitoes, bites, and more. 

The Mosquito Alert app is focused specifically on five different mosquito species that are particularly important in the spread of disease to humans. 

By clicking on the Settings icon at the top left from any screen of the app, users can access an app tutorial on mosquito identification or a Mosquito guide to note distinguishing features that can help identify particular mosquito species, see photo examples of mosquito larvae and breeding sites, and more.

4 types of Aedes mosquitoes in Europe
body parts of the mosquito

Once users have set up an account, they can use the app to take one of four actions:

  • Report a mosquito bite
  • Report adult mosquito activity
  • Report a breeding site
  • Or view data they have submitted
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app that monitors mosquito activity

When reporting a bite, users will be asked several questions:

  • How many bites they received
  • Using a diagram, select where on their body they were bitten 
  • Select your general location where you were bitten (inside a vehicle, inside a building, outdoors, or do not know)
  • When they were bitten

If users use the app to report a breeding site, a different set of questions will appear. They will be asked whether or not the site is a storm drain or another location. For either option, users will be asked to take a photo of the location. 

If reporting an adult mosquito, the user will be asked to select the type of mosquito they think it was by species, take a photograph if possible, and mark their location (if location services are enabled on the user’s device, the device will automatically record the location on a map).

As of April 2023, the Mosquito Alert app reports having over 278,000 participants around the world and averages nearly 30 reports from citizen scientists each day.

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It's Up to Us to Improve The Data

As with any scientific project, data is invaluable. These apps, and the data they provide to mosquito researchers, will get better as more users report mosquito breeding sites and activity near their locations. YOU can be a part of this important citizen science by downloading one or both of these apps and reporting mosquito conditions near you. 

If you work with or have children, utilizing these apps can be a great science project and learning opportunity by involving them in STEM (Science, Technology, Engineering, and Mathematics) while they are young. 

Don't Forget To Report Mosquitoes To Your Local Authorities

While citizen science apps are a helpful tool for global research, it’s important to remember to report mosquito breeding sites and unusual mosquito activity to local authorities in your community. This will ensure the quickest and most effective action is taken to reduce the risks mosquitoes pose to you, your family, your neighbors, and your community at large. 

While the authority you should report activity to varies by community, calling your local mosquito control board or health department is typically a great start. In some communities, you may be able to call 311 and ask about reporting mosquitoes to get you to the right resources. 

Implementing Integrated Mosquito Management in Your Community

VDCI is proud to partner with government agencies, municipalities, and businesses across the United States to help reduce mosquito populations and eliminate risks in their communities. For more information on our programs, implementing an Integrated Mosquito Management program in your community, and other helpful resources, visit vdci.net. 

Contact Us to Learn More About Effective Mosquito Prevention Strategies:

VDCI_Logo_square Since 1992, Vector Disease Control International (VDCI) has taken pride in providing municipalities, mosquito abatement districts, industrial sites, planned communities, homeowners associations, and golf courses with the tools they need to run effective mosquito control programs. We are determined to protect the public health of the communities in which we operate. Our mosquito control professionals have over 100 years of combined experience in the field of public health, specifically vector disease control. We strive to provide the most effective and scientifically sound mosquito surveillance and control programs possible based on an Integrated Mosquito Management approach recommended by the American Mosquito Control Association (AMCA) and Centers for Disease Control and Prevention (CDC). VDCI is the only company in the country that can manage all aspects of an integrated mosquito management program, from surveillance to disease testing to aerial application in emergency situations.