Mosquito Borne Diseases


Mosquito Protective Measures for the Homeowner

Personal Protective Measures:

Avoid outdoor activities at dawn and dusk when mosquitoes are most active.

If you must be outdoors wear long-sleeved shirts, long pants, and use mosquito repellent that contains DEET and follow the directions on the label.

Cover up the arms and legs of children playing outdoors near swampy areas. When outdoors, cover babies’ playpens or carriages with mosquito netting.

Don’t camp overnight near freshwater swamps where mosquitoes are most active. When camping outdoors in tents in other areas, make sure your tent is equipped with mosquito netting.

Protective Measures for Property:

Don’t let standing water collect around your home in ditches, clogged gutters, old tires, wheelbarrows, bird baths, used tires, flower pots, dishes, hollow trees, wading pools and children’s toys. Any standing water should be drained.

Fix any holes in screens and make sure they are tightly attached to all doors and windows.

A number of safe and effective mosquito breeding prevention products are available at local garden centers, nurseries and hardware stores.

For the latest test results, contact the Mosquito Information Line at (860) 424-4184. You can also access information at

Another useful site for information about West Nile Fever:

West Nile Fever

What is West Nile Fever?

West Nile Fever is a mosquito-borne viral infection that can cause inflammation of the brain. It is named after the West Nile district of Uganda where the virus was first isolated in 1937. The viruses that cause West Nile Fever and St. Louis Encephalitis come from the same family of flaviviruses and cause diseases that are similar to one another.

Has West Nile-like virus been found in Connecticut?

A West-Nile-like virus has been found in two species of mosquitoes trapped in Greenwich and in the brain tissue of a crow from Westport. The crow had evidence of encephalitis, but it is not known what role the virus had in the bird’s death, if any.

Have there been any human cases of West Nile Fever in Connecticut?

No. The Connecticut Depatment of Public Health (DPH) has asked physicians to report suspect cases of West Nile Fever immediately to the DPH.

How do people get West Nile Fever?

West Nile-like virus, like St. Louis Encephalitis virus, is spread to humans by the bite of infected mosquitoes (primarily the Culex species). A mosquito is infected by biting a bird that carries the virus. West Nile virus is not spread by person-to-person contact, or directly from birds to persons.

What are the symptoms of West Nile Fever?

The symptoms of West Nile Fever infection are very similar to those of St. Louis Encephalitis virus. Most people who are infected have no symptoms or may experience mild illness such as a fever and headache before fully recovering. In some individuals, particularly the elderly, West Nile virus can cause serious disease that affects the central nervous system. At its most serious, it can cause permanent neurological damage and can be fatal. Symptoms generally occur 5 – 15 days following the bite of an infected mosquito, and range from a slight fever, headache, rash, swollen nodes and conjunctivitis (irritation of the lining of the eye) to the rapid onset of severe headache, high fever, stiff neck, disorientation, muscle weakness, coma, or death.

Who is at risk of contracting West Nile Fever?

Anyone can become infected with the virus. However, the very old are more likely to become ill and develop serious symptoms when infected.

If I live in an area where birds with West Nile-like virus have been reported and I am bitten by a mosquito, am I likely to get sick?

No. Even in areas where mosquitoes do carry the virus, very few mosquitoes — perhaps only one out of 1,000 — are infected. The chance that one mosquito bite will be from an infected mosquito is very small.

If bitten by an infected mosquito, will I get sick?

If bitten by an infected mosquito, your chances of developing the illness are roughly one in 300.

If bitten, should I be tested for West Nile-like virus?

No. Most mosquitoes are not infected with the West Nile-like virus. Illnesses related to mosquito bites are rare. However, you should see a doctor immediately if you develop symptoms such as high fever, confusion, muscle weakness, or severe headaches. Patients with mild symptoms are likely to recover completely, and do not require any specific medication or laboratory testing.

Is there a treatment for West Nile Fever?

Although there is no specific treatment, medication or cure, the symptoms and complications of the disease can be treated. Most people who get this illness recover from it.

If there a vaccine for West Nile Fever?

No vaccine for West Nile Fever exists.

What measures are being taken to protect the population?

Connecticut has implemented an aggressive mosquito control strategy, including mosquito surveillance, testing, and ground spraying activities using a pyrethroid-based insecticide (called Resmethrin) to reduce the mosquito population and prevent the transmission of mosquito-borne viruses

Is there more concern now that the West Nile-like virus has been found in Connecticut?

No. The disease caused by West Nile-like virus is very similar to St. Louis Encephalitis. The public health response is the same regardless of which mosquito-borne virus is found. All of the recommendations for protection against mosquitoes and mosquito control actions remain the same.

You can find additional information in the following brochure:

Additional information is available at