Infection with Saint Louis Encephalitis virus rarely results in severe symptoms. It is closely related to West Nile virus and distinguishing between the viruses requires advanced diagnostic tests.
Infected mosquitoes pass the virus to birds when they take a blood meal.
Mosquitoes can transmit St. Louis encephalitis virus to humans too. Few infected people develop symptoms, but serious disease can occur. The health risk is higher for elderly and immune compromised persons. Saint Louis Encephalitis was last detected in mosquito samples within the District in 1993, but is currently re-emerging in various areas of California.
Severe Symptoms:
Headache
High fever
Neck stiffness
Stupor
Disorientation
Coma
Tremors
Additional Resources:
California Department of Public Health: St Louis Encephalitis
Centers for Disease Control and Prevention: St Louis Encephalitis