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Scoll down the page to learn about Arboviral Infections.

Arboviral infections are caused by viruses transmitted by arthropods (arthropod borne virus). Although up to 80% of persons who get an arboviral infection have no clinical symptoms, encephalitis (inflammation of the brain) is a common and potentially life-threatening complication that is often reported among infected persons that do develop symptoms. Symptoms generally begin 1 to 2 weeks after a mosquito bite. There is no specific treatment available for arboviral infections.

The most common arboviruses in the United States include West Nile virus, eastern equine encephalitis virus, western equine encephalitis virus, Powassan encephalitis virus, St. Louis encephalitis virus, and La Crosse encephalitis virus. The most commonly reported arbovirus in West Virginia is La Crosse encephalitis. Arboviral infections commonly occur during the summer and fall months when mosquitoes are active. Prevention of arboviral infection includes removing containers that collect water near homes (where mosquitoes lay eggs) and the regular use of mosquito repellants.

Aedes triseriatus Discarded tires can be breeding grounds. Birds can be carriers of arbovirus.

Aedes triseriatus is the main vector for La Crosse encephalitis. It is a day-biting mosquito species. Females usually lay their eggs in pools of water in tree holes and also in man-made water holding containers, like discarded tires.

Mosquitoes can lay eggs even in small amounts of standing water. Discarded tires serve as perfect artificial breeding sites since water can accumulate inside of them.

West Nile virus has been identified in more than 200 species of birds, including the American Crow. Most of these birds were identified through public reporting of dead birds.

Reporting Guidelines

Report within one week to local health department


Arboviral Infection Surveillance Protocol

Case Definition

CDC Case Definition

Required Forms


Arboviral Encephalitis Report Form

Office of Laboratory Services Submission Form for Human Specimens

West Virginia Zoonotic Disease Surveillance Summary, 2014 Click at left to view the 2014 surveillance information about mosquito-borne, tickborne, and other reportable zoonotic diseases.

West Virginia Vectorborne Disease Summary 2015

West Virginia Mosquito-borne Disease Surveillance Report 2013

West Virginia Mosquito-borne Disease Surveillance Report 2012

West Virginia Mosquito-borne Disease Surveillance Report 2011

West Virginia Mosquito-borne Disease Surveillance Report 2010

Archived Surveillance Data

General Information

Mosquito Public Information Sheet

Mosquito-borne Illness Prevention Checklist

Arbovirus Provider Information Sheet

Arboviral Testing at the Office of Laboratory Services

Tools for Local Health Departments

Arbovirus Model Press Release

Dead Bird Log

Case Ascertainment Guide for Arboviral Case Investigations

For More Information:

CDC Arboviral Encephalitides

CDC Guidelines for Arbovirus Surveillance Programs in the US

USGS Arboviral Disease Maps

WV Department of Environmental Protection Open Dump Reporting

West Virginia Veterinary Office of Laboratory Services Arbovirus Testing and Submission Page

West Virginia Mosquito-borne Disease Information (LaCrosse Encephalitis, Eastern Equine Encephalitis, Western Equine Encephalitis, West Nile Virus, and St. Louis Encephalitis)