Eastern equine encephalitis, a mosquito-borne virus, has instilled concern as states along the East and Gulf Coasts grapple with the potential for larger outbreaks — and with next steps. As of Sept. 10, a total of four EEE cases have been reported in Massachusetts, according to the Centers for Disease Control and Prevention.

WNV is typically spread when an infected mosquito bites an individual, and can produce a range of reactions, from zero symptoms to severe ones that require hospitalization.