True or False: The Culex pipiens and Culex tarsalis are common carriers of West Nile virus.

The statement is true because both Culex pipiens and Culex tarsalis are known vectors for the West Nile virus. These mosquito species are efficient at transmitting the virus from infected birds to humans and other animals.

Culex pipiens, also known as the common house mosquito, is widely distributed in urban and suburban areas, making it a significant carrier of various arboviruses, including West Nile virus. Meanwhile, Culex tarsalis is particularly prevalent in rural areas and is noted for its role in maintaining the transmission cycle of West Nile virus in these regions.

Understanding the role of these mosquito species in the transmission of West Nile virus is critical for public health efforts aimed at controlling mosquito populations and mitigating the risk of virus transmission to humans. The other options do not reflect the fact that both species are involved in the transmission of the virus.