Based on data collected from May 24, 2017 to July 26, 2017, the West Virginia Department of Health and Human Resources, Bureau for Public Health Mosquito Surveillance Program is reporting several West Nile virus (WNV) positive mosquito pools across West Virginia with the greatest number of infected mosquitoes from Cabell County. WNV positive mosquito pools have also been detected in Berkeley, Fayette, Kanawha, Putnam, Wayne, Wetzel, and Wood counties this season.
As of August 22, 2017, human and/or non-human (i.e. mosquito, horse, and dead horse) WNV activity has been reported in 45 states, including those that share a border with West Virginia. Though no human WNV cases have been reported in West Virginia to date, increased activity in mosquitoes may indicate an increased risk to humans. Healthcare providers can assist public health in preventing WNV and other mosquito-borne diseases by encouraging patients to remove potential mosquito breeding sites around their homes and practice mosquito bite prevention techniques. For more information on mosquito bite prevention, visit the Centers for Disease Control and Prevention website at https://www.cdc.gov/westnile/prevention/index.html.
The Bureau for Public Health uses exposure, clinical, and laboratory information to assess the risk of WNV to West Virginia residents. Symptoms of WNV infection vary in severity with about 8 of 10 people showing no symptoms of infection. Severe neuro-invasive disease may result in death in some cases. Healthcare providers should consider WNV infection as a differential diagnosis among patients with encephalitis or meningitis through the rest of the mosquito-borne disease season (May-October). The preferred diagnostic test for WNV and other arboviral encephalitis is virus-specific IgM antibodies in cerebrospinal fluid (CSF) or serum. WNV- specific IgM antibodies are usually detectable 3 to 8 days after onset of illness and may persist for 30 to 90 days. The West Virginia Office of Laboratory Services (OLS) offers a complete arboviral disease panel that includes the WNV and is free-of-charge. For more information, contact the OLS at (304) 558-3530.
The WNV and other arboviral diseases are reportable to the local health department in the patient’s county of residence within one week. For more information, contact your local health department or the Division of Infectious Disease Epidemiology at 1 (800) 423-1271, extension 1; (304) 558-5358, extension 1; or the answering service at (304) 925-9946.