Which mosquito genus is considered the most important vector for West Nile virus in the United States?

Which mosquito genus is considered the most important vector for West Nile virus in the United States?

• A. Aedes
• B. Culex
• C. Anopheles
• D. Culiseta

Answer: (B)

West Nile virus relies on mosquitoes to move between birds and people. In the United States, the main vectors are Culex mosquitoes. They bite birds most often, keeping the virus circulating in the bird–mosquito cycle, and occasionally bite humans or horses, which leads to human cases. Culex species such as those common here are widespread and efficient at transmitting the virus after the virus has had time to develop inside the mosquito (the extrinsic incubation period). Other mosquito genera can carry West Nile in some situations, but they are not the primary drivers of transmission in the U.S.; Anopheles vectors malaria, Aedes transmits other diseases like dengue and Zika, and Culiseta is less central for West Nile here. So, Culex is the most important West Nile virus vector in the United States.

West Nile virus relies on mosquitoes to move between birds and people. In the United States, the main vectors are Culex mosquitoes. They bite birds most often, keeping the virus circulating in the bird–mosquito cycle, and occasionally bite humans or horses, which leads to human cases. Culex species such as those common here are widespread and efficient at transmitting the virus after the virus has had time to develop inside the mosquito (the extrinsic incubation period). Other mosquito genera can carry West Nile in some situations, but they are not the primary drivers of transmission in the U.S.; Anopheles vectors malaria, Aedes transmits other diseases like dengue and Zika, and Culiseta is less central for West Nile here. So, Culex is the most important West Nile virus vector in the United States.