State health officials are confirming a ninth human case of West Nile virus in Massachusetts.
The Department of Public Health said Wednesday that the most recent case is a Middlesex County woman in her 30s who has recovered. Six other cases have been reported in Middlesex County this year, and one each in Hampden and Berkshire counties.
The health department said the mosquito-borne illness also has been confirmed in a horse in Hampden County.
The findings have led officials to declare a new "critical" mosquito threat level in Chicopee and "high" threat level in Granby, Holyoke, Springfield, South Hadley, and West Springfield.
Last year there were six human cases in the state and one in a horse.
People are urged to take precautions against mosquitoes, including using repellent and protective clothing and avoiding outdoor activities at night.
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