Be alert: West Nile virus found in Manchester mosquitoes

MANCHESTER, NH – As school athletics ramps up and many families spend more time outdoors enjoying hiking trails and other activities, the city Health Department issued a notice Wednesday that West Nile Virus was detected in a mosquito swarm collected in Manchester on Aug. 15. again on August 22.

“These are the second and third detections in Manchester this summer,” he said, according to the memo.

In accordance with the NH Department of Health and Human Services’ Arboviral Diseases, Surveillance, Prevention and Response Plan1, the local risk level has been raised to “moderate”.

Anna Thomas, MPH, Manchester’s director of public health, said residents should continue to protect themselves when participating in planned outdoor activities.

“We want to remind all Manchester residents and neighboring communities to continue to take measures to prevent mosquito bites and remove standing water from their properties. Personal protective measures, such as using an effective mosquito repellent, are the single most effective way to minimize risk.

This combination of EPA-rated repellents is considered the most effective against mosquitoes.

Avon Skin So Soft Bug Guard Plus is a popular EPA-listed repellent.

From memory:

Every summer/fall since 2000, the City of Manchester Health Department collects and sorts mosquitoes, which are then tested for WNV, Eastern Equine Encephalitis (EEE), and Jamestown Canyon Virus (JCV) by the NH Public Health Laboratory. This information is useful in determining disease risk for humans. Public health interventions such as adult mosquito spraying may be indicated in accordance with State and Local plans if additional positive mosquito swarms (“High Risk”) are detected demonstrating continued disease transmission. The Manchester Health Department maintains an annual Special Permit (SP-068) with the NH Department of Agriculture Pesticide Control Division to permit accelerated spraying by licensed pest control professionals in such cases.

WNV is one of three arboviruses transmitted by the bite of infected mosquitoes in New Hampshire. Other viruses are Eastern Equine Encephalitis (EEE) and Jamestown Canyon virus (JCV). WNV was first identified in August 2000 in New Hampshire. Symptoms usually appear a week after the bite and can include a flu-like illness, including fever, muscle aches, headaches, and fatigue. Many people may develop no symptoms or only very mild symptoms. A very small percentage of individuals infected with WNV may develop more serious central nervous system diseases, including meningitis or encephalitis. If you or someone you know has flu-like symptoms, including fever and headache, contact your local healthcare provider.

Guidelines for preventing WNV and other arboviruses can be found here:

Anyone with questions about arboviruses, including WNV, can call the New Hampshire Bureau of Infectious Disease Control at 603-271-4496.

For more information, visit the Centers for Disease Control and Prevention website at

Prevention Guidelines for West Nile Virus and Eastern Equine Encephalitis

1. Eliminate standing water and other mosquito breeding grounds.

In hot weather, mosquitoes can breed in any pond for more than 4 days!

· Remove old tires from your property.

· Throw away tin cans, plastic containers, ceramic pots or other containers. Don’t overlook containers overgrown with aquatic plants.

· Dig holes in the bottom of recycling bins left outside.

· Make sure roof gutters are clean and properly drained.

· Clean and chlorinate pools and hot tubs. Store loose and capped if not in use and keep caps away from standing water.

· Aerate garden ponds or stock them with fish.

· Turn the wheelbarrows and change the water in the birdbaths at least twice a week.

· Turn plastic water pools when not in use.

· Reminding or helping neighbors to eliminate breeding areas on their properties.

· Manchester residents can report “artificial mosquito breeding areas”: rimless tires, neglected swimming pools and other man-made water areas for investigation to the Manchester Health Department – (603) 624-6466 and contact Environmental Health. Branch.

2. Pay attention to where mosquitoes live and breed and prevent them from entering your home.

· Mosquitoes lay their eggs in standing water. Weeds, tall grasses, and shrubs provide an open home for adult mosquitoes, including several species associated with West Nile virus and eastern equine encephalitis.

· Mosquitoes can enter homes through unscreened windows or doors or through broken screens. Make sure doors and windows have tight-fitting screens. Repair or replace all screens in your home that have tears or holes.

· Resting mosquitoes are often found under beds, behind beds, etc. can be flushed from indoor resting areas by sweeping motions and destroyed once in flight before going to bed at night.

3. Protect yourself from mosquito bites.

· Children and adults should wear protective clothing such as long pants, long-sleeved shirts, and socks if outside during the evening, night, and early morning when mosquitoes are most active and likely to bite.

· Consider using an effective insect repellent that contains DEET. Repellent for children and adults with 30% or less DEET (N,N-diethyl-methyl-meta-toluamide). Use DEET according to the manufacturer’s directions. Children should not apply DEET to themselves. Repellents containing Picaridin, paramenthan-diol, or oil of lemon eucalyptus have also been found to be effective.

· Vitamin B, ultrasound devices, incense, and bug bites have not been shown to be effective in preventing mosquito bites.

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