Which genus is known to be a major vector of West Nile and St. Louis encephalitis in the United States?

The genus that is recognized as a major vector of both West Nile virus and St. Louis encephalitis in the United States is Culex. This genus includes several species that are highly capable of transmitting these viruses due to their feeding habits and breeding preferences. Culex mosquitoes are primarily found in urban and suburban areas where they can utilize stagnant water sources for breeding, which increases their contact with humans and makes them effective vectors.

Furthermore, Culex species tend to be active during the evening and night hours, aligning with the peak periods of virus transmission. Their role as vectors is supported by studies that have documented their capacity to both acquire and transmit the pathogens responsible for these diseases, solidifying their place as significant contributors to public health concerns related to arboviral transmissions in the United States.