The Massachusetts Department of Public Health (DPH) this week reported a 7-month old horse from Middleborough was diagnosed with Eastern equine encephalitis (EEE). Infection was confirmed by the William Hinton State Laboratory Institute on July 23. The colt developed clinical signs on July 20, his condition deteriorated very rapidly, and he was euthanized on July 21.

The last Massachusetts horse confirmed to have EEE was in September 2009 in Essex County. There were no human cases of EEE during 2009; however, there were 13 cases with six deaths from 2004 through 2006. The disease is spread to horses and humans through the bite of an infected mosquito.

"We are seeing early indicators that lead us to believe this may be a bad EEE year," said DPH State Epidemiologist Alfred DeMaria, MD. "Evidence of EEE-infected mosquitoes and a horse with EEE this early in the season is similar to what we saw in 2006, and we had five human cases that year. We urge people to take this seriously and do what they need to do to protect themselves and their families."

Massachusetts EEE and West Nile virus testing results for 2010 and risk category maps can be found on the DPH Arbovirus Surveillance Information website (under "Arbovirus Daily Update")