NH DHHS Identifies First Mosquito Batch In 2020 To Test Positive For West Nile Virus

Concord, NH – The New Hampshire Department of Health and Human Services (DHHS) has identified the first batch of mosquitoes to test positive for West Nile Virus (WNV) this season. The batch was found recently in the city of Manchester. DHHS is working in partnership with the City of Manchester Health Department on providing additional risk mitigation information to Manchester residents and surrounding towns.

“West Nile virus is transmitted to humans from the bite of an infected mosquito,” said NH State Epidemiologist, Dr. Benjamin Chan. “The best way to prevent WNV and other mosquito-transmitted infections is to take steps to avoid mosquito bites by using an insect repellent effective against mosquitoes, avoid being outdoors between dusk and dawn when mosquitoes are most active, and remove any standing water from around the home, where mosquitoes reproduce.”

WNV is an arbovirus transmitted from the bite of an infected mosquito. WNV was first identified in New Hampshire in August of 2000. For the last decade, WNV activity has been detected every year in NH. The most recent human case of WNV in NH was in an adult in 2017. Typically, WNV activity increases in years where drought conditions exist. Even though we have been experiencing cooler fall weather, the risk for WNV and Eastern Equine Encephalitis virus (EEEV) will continue to increase until there is a statewide mosquito killing hard frost.

Symptoms of WNV usually appear within a week after being bitten by an infected mosquito, although many people can be infected and not develop any symptoms, or only develop very mild symptoms. Symptoms can include flu-like illness including fever, muscle aches, headaches, and fatigue. A very small percentage of individuals infected with WNV can go on to develop more serious central nervous system disease, including meningitis or encephalitis. If you or someone you know is experiencing flu-like symptoms, including fever and headache, contact your local medical provider.

Prevention guidelines for WNV, and other arboviral diseases of concern, can be found below. Anyone with questions about arboviruses can call the New Hampshire Bureau if Infectious Disease Control at 603-271-4496. For more information, please visit the Centers for Disease Control and Prevention website at www.cdc.gov.