Arboviral Infections

What are arboviral infections?

Arboviral (short for arthropod-borne) infections are caused by any of a number of viruses spread by arthropods such as mosquitoes and ticks. These infections generally occur during warm weather months when mosquitoes are active. The term encephalitis refers to an inflammation of the brain which an arbovirus infection can cause. In Wisconsin, California (La Crosse) encephalitis is the most commonly reported arboviral infection. In spite of the name, La Crosse encephalitis is not confined to the La Crosse County area.

Who gets arboviral infections?

Anyone can get an arboviral infection. Susceptibility to disease is highest in infancy and old age. Children appear to be most susceptible to La Crosse encephalitis.

How are arboviral infections spread?

Most arboviral infections are spread by the bite from an infected mosquito. Fortunately, only a few types of mosquitoes are capable of transmitting the disease and only a small number of the mosquitoes are actually carrying the virus.

What are the symptoms of arboviral infections?

Symptoms of the various types of viral infections transmitted by mosquitoes are usually similar but differ in severity. Most infections do not result in any symptoms. Mild cases may occur with only a slight fever and/or headache. Severe infections are marked by a rapid onset of headache, high fever, disorientation, coma, tremors, convulsion and infrequently paralysis or death.

How soon after a bite from an infected mosqito do symptoms occur?

Symptoms usually occur 5 to 15 days after a bite from an infective mosquito.

Does past infection with an arbovirus make a person immune?

Yes, infection with an arbovirus can provide immunity to that specific virus and perhaps to other related viruses.

What is the treatment for an infection due to an arbovirus?

The physician will usually attempt to relieve the symptoms of the illness, but there is no specific treatment available for arbovirus infections.

How can arboviral infections be prevented?

Insect repellents can be used when outdoors in mosquito-infested areas. Homes can be screened to prevent entry of mosquitoes. Communities or municipalities may establish a mosquito surveillance or control program to reduce mosquito populations by applying pesticides and draining swampy areas.

In Wisconsin the mosquito that carries the virus causing California (LaCrosse) encephalitis breeds in tree holes and containers that retain water. Therefore, it is important to clean up areas around households and other locations where children play. Fill tree holes and remove old tires, tin cans and other containers that hold water and can provide places for mosquitoes to breed. Birdbaths should be cleaned and the water changed on a frequent basis.

Each year, Medical College of Wisconsin physicians care for more than 180,000 patients, representing nearly 500,000 patient visits. Medical College physicians practice at Children's Hospital of Wisconsin, Froedtert Memorial Lutheran Hospital, the Milwaukee VA Medical Center, and many other hospitals and clinics in Milwaukee and southeastern Wisconsin.