The CDC is urging Americans to take certain protections against mosquito bites due to increased West Nile virus activity so far this season. CIDRAP has the news.

The U.S. has seen the “most cases of West Nile disease in people by this time of year since 2004” this year. Of the “48 infections reported by 12 states as of June 30, 38 (79%) have caused severe neuroinvasive illness. This is a marked rise from the average 10 cases usually reported to the CDC by June 30.”

23 states are reporting West Nile virus activity, which is the highest number recorded over the last 10 years. WNV is the “country’s leading cause of mosquito-borne illness, accounting for an average of several thousand infections and about 100 deaths each year. Most infected people have no symptoms, but about 20% develop a fever and symptoms such as headache, body aches, joint pain, vomiting, diarrhea, or a rash.” Less than 1% of infected people experience “severe neurologic disease, including meningitis or encephalitis.”

This year, Arizona has reported the most human cases with 32. Texas has logged four and Tennessee has logged two. Several other states have each documented one. The CDC advises wearing “long, loose-fitting clothing; avoiding being outdoors at night; and using screens on windows and doors or air conditioning to keep mosquitoes out.”