State Officials Confirm First Human Case of West Nile Virus

The Massachusetts Department of Public Health confirmed the state’s first human case of West Nile Virus on Thursday.

Public Health officials say the man is a resident of Middlesex County, in his 40’s, who was diagnosed with West Nile Virus by testing completed Thursday by the State Public Health Laboratory. He is currently hospitalized.

The DPH is investigating to determine where he may have been exposed. Once identified, those areas will be assessed to determine risk for the virus. It is not currently known where he may have been exposed.

“Massachusetts is in peak season for possible West Nile virus infection for human infections,” said DPH State Public Health Veterinarian Dr. Catherine Brown in a statement issued Thursday. “We need to continue to take steps to protect ourselves against mosquito bites: use insect repellant, cover up, and reduce outdoor activities at dusk and after nightfall when mosquitoes are at their most active.”

In 2014, there were six human cases of West Nile Virus infection identified in Massachusetts. West Nile Virus is usually transmitted to humans through the bite of an infected mosquito. While West Nile Virus can infect people of all ages, people over the age of 50 are at higher risk for severe disease. Most people infected with West Nile Virus will have no symptoms. When present, West Nile Virus symptoms tend to include fever and flu-like illness. In rare cases, more severe illness can occur.

Last week state health officials announced the West Nile Virus was detected in mosquito samples taken in Arlington and Lexington. At the time they said the risk level for human infection remained moderate as the virus circulates among local mosquito populations.

Officials say the consistently high temperatures in the region over the past few weeks have created an environment that is historically associated with higher human illness rates.

The Department of Public Health is offering these tips to protect yourself from caused by mosquitoes:

Avoid Mosquito Bites

Apply Insect Repellent when Outdoors
Use a repellent with DEET (N, N-diethyl-m-toluamide), permethrin, picaridin (KBR 3023), oil of lemon eucalyptus [p-methane 3, 8-diol (PMD)] or IR3535 according to the instructions on the product label. DEET products should not be used on infants under two months of age and should be used in concentrations of 30% or less on older children. Oil of lemon eucalyptus should not be used on children under three years of age.

Be Aware of Peak Mosquito Hours
The hours from dusk to dawn are peak biting times for many mosquitoes. Consider rescheduling outdoor activities that occur during evening or early morning.

Clothing Can Help Reduce Mosquito Bites
Wearing long-sleeves, long pants and socks when outdoors will help keep mosquitoes away from your skin.

Mosquito-Proof Your Home

Drain Standing Water
Mosquitoes lay their eggs in standing water. Limit the number of places around your home for mosquitoes to breed by either draining or discarding items that hold water. Check rain gutters and drains. Empty any unused flowerpots and wading pools, and change water in birdbaths frequently.

Install or Repair Screens
Keep mosquitoes outside by having tightly-fitting screens on all of your windows and doors.

Protect Your Animals

Animal owners should reduce potential mosquito breeding sites on their property by eliminating standing water from containers such as buckets, tires, and wading pools — especially after heavy rains. Water troughs provide excellent mosquito breeding habitats and should be flushed out at least once a week during the summer months to reduce mosquitoes near paddock areas. Horse owners should keep horses in indoor stalls at night to reduce their risk of exposure to mosquitoes. Owners should also speak with their veterinarian about mosquito repellents approved for use in animals and vaccinations to prevent WNV and EEE. If an animal is diagnosed with WNV or EEE, owners are required to report to DAR, Division of Animal Health by calling 617-626-1795 and to the Department of Public Health (DPH) by calling 617-983-6800.

More information, including all WNV and EEE positive results, can be found on the Arbovirus Surveillance Information web page or by calling the DPH Epidemiology Program at 617-983-6800.