How common is west nile virus in the us?

Uncommon: In 2010, the CDC reported 1021 proved cases in the USA, with 629 being neuroinvasive. If we take the retrospective studies of who has antibodies and suppose that one person in 100 who meets the virus will get some clinically-diagnosable brain disease, that it around 60,000 cases, the large majority never knowing they were infected.

Not uncommon: Can be seen throughout the usa, but especially in the summertime, where there is abundant mosquito breeding such as in irrigated farmlands, with stagnant areas of water. Most infections are not noticed, and many seem like mild flu. Very rarely, especially in immune compromised people, does it affect brain and spinal cord.

West Nile Virus: 2,544 cases of West Nile virus disease in the US were reported to the CDC in 2018.