SPRINGFIELD, Mass. (WWLP) — Mosquitoes start becoming more active again once air temperatures regularly hit above 50-55 degrees. This week, we’re a little cooler, but temperatures in May will be much warmer than this, indicating a significant increase in activity levels. In Massachusetts, the mosquito-borne diseases to watch out for are EEE — Eastern Equine Encephalitis, and West Nile Virus. 

According to the CDC, EEE is a rare cause of brain infections. It’s not common, only a few cases are reported in the U.S. every year, but Massachusetts is one of the states with the highest number of cases. There is no vaccine or antiviral treatment for human infection, and 30 percent of people with EEE die, while many survivors have ongoing neurological problems. 

EEE average annual incidence by county from 2009-2018. (CDC)

People who engage in outdoor work and recreational activities are at increased risk of infection. 

The CDC says West Nile Virus is the leading cause of mosquito-borne disease in the continental U.S. 

Most people infected do not feel sick, but 1 in 5 people infected will develop a fever and other symptoms such as headache, body aches, joint pains, vomiting, diarrhea, or rash. Only 1 in 150 people will develop serious symptoms. 1 in 10 of the people who develop the serious symptoms affecting the central nervous system die. 

The easiest way to prevent EEE or West Nile Virus infection is by wearing bug spray, long-sleeved shirts, long pants, and socks when outside. Also avoid peak mosquito activity time which is from dusk to dawn.