For Immediate Release - September 23, 2013

State Health Officials Announce Fourth Human Case of West Nile Virus in Massachusetts

Residents urged to take precautions to avoid mosquito bites

BOSTON — The Massachusetts Department of Public Health (DPH) today announced the fourth human case of West Nile virus (WNV) in the state this year. The man, a resident of Essex County in his 60’s, was hospitalized but later discharged. Testing was completed at the Hinton State Laboratory Institute (HSLI) today.

The epidemiological investigation conducted by DPH indicates that the patient was most likely exposed to infected mosquitoes in Essex County. This area is already considered to be at moderate risk from WNV and will remain at that level. Moderate risk areas may have a single animal or human case; multiple cases from an area would indicate that risk from WNV is high.

“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,” said DPH State Public Health Veterinarian Dr. Catherine Brown. “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.

Last year, thirty-three cases of WNV were detected in Massachusetts residents. 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 Department of Agriculture (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 2013, can be found on the Arbovirus Surveillance Information web page at www.mass.gov/dph/mosquito or by calling the DPH Epidemiology Program at 617-983-6800.

DPH has produced a series of 30-second videos on how to prevent mosquito and tick bites and the illnesses that can result. All videos can be found at www.mass.gov/MosquitoesAndTicks. Media outlets are encouraged to share these videos on their websites. Instructions on how to embed the videos into external websites are included on this web page.

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