What is the Oropouche virus, and How Does it Spread?
Oropouche fever is a viral disease caused by the Oropouche virus (OROV), primarily affecting people in South America’s Amazon Basin. However, reports released by CNN Brazil, the Miami Herald, Science.org, and the American Mosquito Control Association (AMCA) in the summer of 2024 have shown that the virus has made its way through populated urban areas of Brazil, Bolivia, Colombia, Peru, and Cuba. This uptick in OROV cases has scientists concerned the virus could lead to a major disease outbreak similar to Zika and chikungunya.
Scientists have speculated the increased spread of OROV could be attributed to several factors, including deforestation and climate change. Due to forests being cleared for urban development, the virus’ animal hosts are no longer available. As a result, midges and mosquitoes are more likely to interact and feed on humans. Furthermore, higher temperatures accelerate the maturation of midges and mosquitoes, while increased rainfall creates more standing water for these vectors to reproduce. Concern is also growing regarding the potential spread of OROV to North America as travel and trade increase, and these vectors continue to adapt to their environment.
What Insects Transmit Oropouche Virus?
The virus is primarily transmitted to humans through the bite of the infected Culicoides paraensis midge and the Culex quinquefasciatus mosquito (common house mosquito). Similar to Zika virus, OROV can also be transmitted from mother to baby during pregnancy. Reports have shown that babies infected with OROV have been born with underdeveloped brains.
 | Symptoms of Oropouche fever |
- High Fever: Patients commonly experience a high fever, which can be one of the initial symptoms of Oropouche fever.
- Headache with Photophobia: Severe headache often accompanied by sensitivity to light is a frequent symptom reported by those infected.
- Myalgia and Arthralgia: Muscle and joint pains are prevalent.
- Additional Symptoms: In some cases, patients may also develop a rash or experience bleeding. Chills, nausea, and vomiting have also been associated with the disease.
 | Treatment of Oropouche fever |
- Currently, there are no vaccines or antiviral treatments for the Oropouche virus.
- Symptom Management: To alleviate high fever and muscle pains, patients are usually treated with medications such as acetaminophen or ibuprofen to reduce fever and pain.
- Hydration and Rest: Adequate fluid intake and rest are crucial to helping the body recover and maintain strength during illness.
- Monitoring and Support: In severe cases, hospitalization might be necessary for close monitoring and supportive care, particularly if complications such as bleeding or severe headaches occur.
Oropouche fever and the United States
As of August 2024, there are no reported locally-acquired cases of OROV in the United States. Travel-associated cases have been identified in the United States. However, concerns are being raised because the vectors that carry this virus are commonly found in the United States. With ongoing deforestation and increasing temperatures, combined with abundant populations of both vectors, experts are concerned that OROV could spread to North America.
A study published in 2023 by Researcher Romero-Álvarez from Infectious Diseases of Poverty, which considered current climate and vegetation loss, suggested that up to 5 million people across the Americas are at risk for contracting the OROV. It’s important to note that the model did not predict the current disease expansion to big cities such as Rio de Janeiro and didn’t factor in future deforestation and climate change.
Know Your Vectors: Culicoides paraensis Midges and Culex quinquefasciatus Mosquitoes
Culicoides paraensis is a tiny biting midge that is primarily responsible for transmitting the OROVs, which causes Oropouche fever. This midge breeds in aquatic habitats and decaying organic matter, like leaves and plants.
Culex quinquefasciatus is a mosquito species notorious for breeding in containers with high organic matter such as flower pots, buckets, toys, bird baths, stagnant ditches, or unused pools. These mosquitoes are predominantly found in residential areas, particularly around homes, making them a significant vector for transmitting diseases to humans. In the United States, they are widespread, especially in the southeastern regions, including states like Florida, Texas, and Louisiana. Given their habitat and breeding preferences, the likelihood of disease transmission is higher due to their close proximity to human populations.
Estimated Range of Potential Vectors
Photo Credit: Center for Disease Control (CDC)
Controlling Culicoides paraensis midges and Culex quinquefasciatus Mosquitoes to mitigate the spread of Oropouche fever
An Integrated Mosquito Management (IMM) program is essential to help prevent mosquito bites and disease transmission in the United States. An effective IMM program includes four environmentally responsible strategies that target disease vectors at all stages of life.
It is critical for the community to understand how to properly eliminate mosquito breeding habitats and take personal protective measures. Furthermore, distributing educational content is important to help the public understand the risk of mosquito-borne disease transmission and the importance of proactive mosquito management efforts in the community.
2: Surveillance
It is critical to determine the mosquito distribution, density, and species composition throughout the target area to understand the risk and address the threat appropriately. Surveillance will also provide direct evidence of an increased transmission risk of the Oropouche virus.
When mosquito larvae are detected in an area, trained and experienced ground crews reduce breeding habitat when possible. They can conduct targeted larvacide applications to remaining areas of standing water, stagnant pools, and water-holding containers. Aerial and ground applications of larvicide via ULV equipment can provide control in hard-to-reach container habitats.
When necessary, adulticide applications are conducted using EPA-approved pesticides in the safest and most environmentally sound way possible. Combined with larvicide efforts, these methods have proven highly effective at significantly reducing the local populations of the target mosquitoes.
Reference List:
What is the Oropouche virus, and how does it spread? (2024, June 5.). Retrieved from https://www.science.org/content/article/little-known-virus-rise-south-america-could-overwhelm-health-systems
Controlling Mosquitoes. (2003). American Mosquito Control Association. Retrieved from https://www.mosquito.org/assets/pdf/24070301-AMG-AMCA-Summer-03/
Robles, F. (2023, March 3). Oropouche virus cases rise in Cuba, prompting health warnings. Miami Herald. Retrieved from https://www.miamiherald.com/news/nation-world/world/americas/cuba/article288883620.html
Febre Oropouche é associada a casos de microcefalia em bebês; entenda o alerta. (2024, January 15). CNN Brasil. Retrieved from https://www.cnnbrasil.com.br/nacional/febre-oropouche-e-associada-a-casos-de-microcefalia-em-bebes-entenda-o-alerta/
VDCI is a company built on the foundations of public health, ethics, professionalism, and technical expertise. We establish vector management programs that are based on an understanding of the underlying vector’s ecology and rooted in the current science of environmentally sound control measures.