The U.S is reporting the largest number of Eastern equine encephalitis cases in more than 50 years, according to STAT.
Health officials have reported 28 cases of EEE this year, marking the highest number of human cases seen in the U.S. since 1964, when the CDC began tracking EEE cases. In 2015, human EEE infections peaked at 21 cases.
Seven states have confirmed human cases in 2019, with Massachusetts reporting the most — 11 cases and four deaths as of Sept. 25. Michigan, New Jersey, Rhode Island, Connecticut, North Carolina and Tennessee have also reported cases this year.
In total, 10 people have died from EEE this year. Massachusetts health officials confirmed the latest death Sept. 26, according to the Albany Herald. Three other EEE deaths occurred in Michigan, two occurred in Connecticut and one occurred in Rhode Island, according to CNN.
EEE is a rare mosquito-borne virus with a 30 percent fatality rate. The U.S. typically reports between three and 15 cases per year, according to the CDC. There is no human vaccine for EEE due to the rarity of the virus and the high cost of vaccine development.