What disease is transmitted by the Culex pipiens mosquito?

The Culex pipiens mosquito is primarily a vector for West Nile virus, which can lead to West Nile fever in humans. This disease can manifest as mild flu-like symptoms in some individuals but can also result in more severe neurological complications in others, particularly among vulnerable populations like the elderly or those with weakened immune systems. The transmission occurs when the mosquito feeds on a host that has the virus, allowing it to acquire the pathogen and subsequently transmit it to humans through bites.

The other options represent diseases that are typically associated with different mosquito species. Plague is primarily transmitted by fleas, while yellow fever is associated with Aedes mosquitoes. Malaria, on the other hand, is transmitted by Anopheles mosquitoes. Understanding the role of specific mosquito species in disease transmission is crucial for implementing effective pest control and public health measures.