State Health Officials Announce Seventeenth Human Case of WNV in Massachusetts

BOSTON — The Massachusetts Department of Public Health (DPH) today announced the seventeenth case of West Nile virus (WNV) in a Massachusetts resident. The Brookline woman, who is in her 20s, was not hospitalized and has recovered. Sixteen communities in Greater Boston are currently at high risk for West Nile virus, including Brookline and Boston.

"Even as overnight temperatures begin to cool, mosquito-borne illness remains a serious threat in Massachusetts and will continue to be until the first hard overnight frost," said DPH State Epidemiologist Dr. Al DeMaria. "People need to continue to use insect repellant, cover up exposed skin, and avoid being outdoors at dusk and after nightfall when mosquitoes are at their most active."

"While this is not a surprise, we are glad that she recovered completely and in fact, did not require hospitalization. This points out the importance of continued awareness and the need to follow recommendations for self-protection until the first hard frost," said Alan Balsam, Director of Public Health and Human Services in Brookline.

WNV infected mosquitoes have been found in 109 communities from nine counties so far during 2012 and health officials predict that the state is on track to have the greatest number of WNV-positive mosquito pools since WNV was first seen in Massachusetts in 2000. There have now been 17 human cases of WNV in Massachusetts, one of which resulted in death. There were six cases of WNV in Massachusetts residents and one in a horse last year. While WNV can infect people of all ages, people over the age of 50 are at higher risk for severe disease. WNV is usually transmitted to humans through the bite of an infected mosquito. Most people infected with WNV will have no symptoms. When present, WNV symptoms tend to include fever and flu-like illness. In rare cases, more severe illness can occur.

People have an important role to play in protecting themselves and their loved ones from illnesses 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. 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 from 2012, can be found on the Arbovirus Surveillance Information web page at www.mass.gov/dph/wnv or by calling the DPH Epidemiology Program at 617-983-6800. The findings of the DPH Eastern Equine Encephalitis Expert Panel can be found here:

• Report of the EEE Expert Panel 

# # #