Mosquito-Borne Viruses in Georgia

Warmer weather means it is mosquito time. Hot weather and summer showers help mosquito populations flourish. While a mosquito can deliver an annoying bite, they can also transmit deadly diseases. 

Several mosquito-borne viruses circulate in Georgia each year and are capable of causing disease in humans and other animals. Mosquito-borne viruses are most active late spring through early fall in Georgia. The most common mosquito-borne viruses in Georgia include:

West Nile Virus

West Nile virus is the most common disease in this country. In 2014, the Centers for Disease Control and Prevention reported 2,122 cases, including 85 deaths.

The World Health Organization describes the West Nile virus in detail:

Key Facts

  • West Nile virus can cause a fatal neurological disease in humans.
  • However, approximately 80% of people who are infected will not show any symptoms.
  • West Nile virus is mainly transmitted to people through the bites of infected mosquitoes.
  • The virus can cause severe disease and death in horses.
  • Vaccines are available for use in horses but not yet available for people.
  • Birds are the natural hosts of West Nile virus.

West Nile Virus (WNV) can cause neurological disease and death in people. WNV is commonly found in Africa, Europe, the Middle East, North America and West Asia. WNV is maintained in nature in a cycle involving transmission between birds and mosquitoes. Humans, horses and other mammals can be infected.

Outbreaks

West Nile Virus (WNV) was first isolated in a woman in the West Nile district of Uganda in 1937. It was identified in birds (crows and columbiformes) in Nile delta region in 1953. Before 1997 WNV was not considered pathogenic for birds, but at that time in Israel a more virulent strain caused the death of different bird species presenting signs of encephalitis and paralysis. Human infections attributable to WNV have been reported in many countries in the World for over 50 years.

In 1999 a WNV circulating in Israel and Tunisia was imported in New York producing a large and dramatic outbreak that spread throughout the continental United States of America (USA) in the following years. The WNV outbreak in USA (1999-2010) highlighted that importation and establishment of vector-borne pathogens outside their current habitat represent a serious danger to the world.

The largest outbreaks occurred in Greece, Israel, Romania, Russia and USA. Outbreak sites are on major birds’ migratory routes. In its original range, WNV was prevalent throughout Africa, parts of Europe, Middle East, West Asia, and Australia. Since its introduction in 1999 into USA, the virus has spread and is now widely established from Canada to Venezuela.

Transmission

Human infection is most often the result of bites from infected mosquitoes. Mosquitoes become infected when they feed on infected birds, which circulate the virus in their blood for a few days. The virus eventually gets into the mosquito’s salivary glands. During later blood meals (when mosquitoes bite), the virus may be injected into humans and animals, where it can multiply and possibly cause illness. The virus may also be transmitted through contact with other infected animals, their blood, or other tissues.

Eastern equine encephalitis virus

“Eastern equine encephalitis virus is an alphavirus that causes a sporadic, mosquito-borne viral infection endemic in the eastern United States and Caribbean. Eastern equine encephalitis (EEE) virus belongs to the arbovirus family. Encephalitis due to EEE virus has its highest incidence during the late summer. EEE is seen most commonly on the eastern and Gulf coasts of the United States, in Caribbean countries, and in South America. It affects predominantly children and elderly people. It is a severe disease with a mortality rate that ranges from 50% to 80%. Patients who survive are left with significant neurologic sequelae. The most severely affected parts of the CNS are the basal ganglia, thalamus, and brainstem. Unlike most viral encephalitides, EEE has a prominent acute neutrophilic infiltrate. Vasculitis with marked endothelial swelling and thrombosis is also characteristic. Necrosis is abundant and may extend to the white matter with small microabscesses,” states ScienceDirect.com.

LaCrosse virus (LAC)

Georgia Division of Public Health explains that “LaCrosse virus (LAC) is a mosquito-borne virus belonging to the California Encephalitis group. LAC rarely causes serious disease in infected persons. Children under 17 years are most at risk of developing symptoms when infected with LAC. Human cases of LAC infection are rare in Georgia (approximately 1 case per year) but are probably under-diagnosed”.

Saint Louis encephalitis virus (SLEV)

Centers for Disease Control and Prevention (CDC) reports that “Saint Louis encephalitis virus (SLEV) is transmitted to humans by the bite of an infected mosquito. Most cases of SLEV disease have occurred in eastern and central states. Most persons infected with SLEV have no apparent illness. Initial symptoms of those who become ill include fever, headache, nausea, vomiting, and tiredness. Severe neuroinvasive disease (often involving encephalitis, an inflammation of the brain) occurs more commonly in older adults. In rare cases, long-term disability or death can result. There is no specific treatment for SLEV infection; care is based on symptoms. You can reduce your risk of being infected with SLEV by using insect repellent, wearing protective clothing, and staying indoors while mosquitoes are most active”.

As you can see, mosquitos are not only annoying but can be very dangerous and one of the most important steps to reducing mosquito populations is to eliminate breeding sites around your home so make sure you discuss your options with your local pest control company.

Houseman Services is the only complete service company in the Athens, GA area. We provide Weed control, fertilization, shrub care, mulch & pine straw, sod, annual plantings, irrigation, and commercial & residential lawn maintenance. We are also state certified and licensed in wood destroying organisms (termite control), household pest control, public heath, and turf & ornamental weed control. We are licensed to control and treat mosquitoes, termites, all pest problems and turf & ornamental weed control. Contact the professionals at Houseman Services and set up a free inspection of your yard. We have been servicing homes and businesses in the Athens, Clarke County area since 1985!