The Southern Nevada Health District is reporting the second human case of St. Louis Encephalitis in Clark County. The individual is male, 50 years of age or older, and did not have the more serious neuroinvasive form of the disease. The Health District will not be providing additional details regarding this individual.

This confirmed case is a reminder to Southern Nevadans that mosquito season is not over and it is important to continue to protect themselves from mosquito bites and eliminate breeding sources around their homes. The Health District is reminding residents that mosquito season can continue well into the fall. Taking steps like applying repellant, wearing protective clothing in the early morning and evening when outdoors, and draining standing water in your yard are simple preventive measures everyone can take.

Symptoms of St. Louis Encephalitis typically develop between five and 15 days after being bitten by an infected mosquito, many infected people never develop any symptoms. Mild infections are characterized by fever and headache without other apparent symptoms. Some people will experience severe illness, especially older adults. Symptoms of the more serious form of the illness include headache, high fever, neck stiffness, confusion, shaking, seizures and/or paralysis, even coma. The illness is diagnosed through a blood test and laboratory confirmation. There is no specific treatment for St. Louis Encephalitis virus disease and mild cases resolve on their own. People with the more serious form of the illness are often hospitalized.

Updated information on positive mosquito submission pools and mosquitoes that are tested in Clark County are posted on the Health District’s Mosquito Surveillance page.

For more information on eliminating breeding sources visit the CDC’s Controlling Mosquitoes at Home page for a list of tips.

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