Massachusetts reports fourth human case of West Nile virus

The Massachusetts Department of Public Health announced the confirmation on Thursday of the fourth human case of West Nile virus in the state this year.

The case was confirmed in a resident of Essex County who is in his 60s after testing at the Hinton State Laboratory Institute. The man required hospitalization but was later discharged.

The DPH determined that the patient was most likely exposed to infected mosquitoes in Essex County, an area already considered to be at moderate risk from the virus. Moderate risk areas may have a single animal or human case. Multiple cases in the area would result in an upgrade to high West Nile virus risk.

"This case underscores the fact that mosquito-borne illness remains a threat in Massachusetts and will continue to be until the first hard overnight frost," Catherine Brown, the DPH state public health veterinarian, said. "People need to continue to use insect repellant and cover up exposed skin. If you are outdoors and you notice a lot of mosquito activity around you, it's a good idea to move inside to avoid it."

There were 33 human cases of West Nile virus reported in Massachusetts in 2012. The virus can infect people of all ages, though individuals over the age of 50 are at higher risk for severe disease. West Nile virus is typically transmitted through the bite of an infected mosquito.