Encephalitis

Saint Louis Encephalitis and WNV can be seasonal, based on the mosquito lifecycle. Mosquito populations are worst in late Spring to early Summer. In Fall, as weather turns colder, the populations begin to die off.

This cycle holds true for northern regions of the United States, where Fall and Winter temperatures get cold. In southern states, mosquito populations can flourish year-round because temperatures do not always get cold enough to impact the population.

People who work outdoors during typical mosquito feeding times (dawn and dusk) are most at risk, along with those whose work sites are near stagnant water, flooded areas, or where standing water occurs.

Saint Louis Encephalitis symptoms can take between several days to around a week to show. Symptoms include:

• Fever
• Headache
• Nausea and vomiting
• Tiredness

Severe cases can cause nervous system infections, resulting in stiffness in the neck, disorientation, convulsions, tremors, paralysis, coma, disability, and even death.

The vast majority of cases go undetected, since the symptoms are similar to the flu or other health issues. Older people are at higher risk for severe cases and potentially death.

To learn more about Outdoor Biological Hazards visit our Outdoor Biological Hazards Online Training web page.