Health officials on Wednesday announced the first human case of West Nile virus in Massachusetts this year.
The individual is a woman in her 80s who was likely exposed to the virus in Middlesex County, an area known to be at moderate risk, the state Department of Public Health said.
The risk of West Nile virus is moderate in the Greater Boston area and also in several towns in Bristol and Worcester counties, health officials said. There have been no deaths this year associated with the virus.
“Risk from West Nile virus has been slow to increase this year. This is an important reminder that we all need to continue to take steps to protect ourselves and our families from mosquito bites," said Margret Cooke, the state's acting public health commissioner.
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In 2020, there were five human cases of West Nile virus in Massachusetts.
West Nile virus is usually transmitted to humans through the bite of an infected mosquito. It can infect people of all ages, though people over the age of 50 are at higher risk for severe disease. Most people infected with the virus have no symptoms. When present, symptoms include fever and flu-like illness.
The substantial amount of rain in the region in July and the recent hot weather have resulted in an increase in the population of the mosquito species known to spread West Nile virus, health officials said. These mosquitoes breed in places where standing water accumulates.