1) What is a mosquito?

A mosquito is a common name for any of about 2000 species of two-winged insects. They are found from the tropics to the Arctic Circle and from lowlands to the peaks of high mountains. Mosquitoes have long, slender wings and are unusual among flies in having small scales over most of the wing veins. The body is narrow. The long antennae have numerous whorls of hair, short in the female and long and bushy in the male. In one large group of mosquitoes, the mouthparts of the female are long, adapted for piercing and for sucking blood. The male, which feeds on nectar and water, has rudimentary mouthparts. Females of this group prefer the blood of warm-blooded animals. When they bite, they inject some of their salivary fluid into the wound, causing swelling and irritation. (Courtesy of Encarta Encyclopedia).

2) What are the stages of a mosquito's life?

After the female mosquito obtains a blood meal (male mosquitoes do not bite), she lays her eggs directly on the surface of stagnant water, in a depression, or on the edge of a container where rainwater may collect and flood the eggs. The eggs hatch and a mosquito larva or "wriggler" emerges. The larva lives in the water, feeds and develops into the third stage of the life cycle called a pupa or "tumbler". The pupa also lives in the water, but no longer feeds. Finally, the mosquito emerges from the pupal case and the water as a fully developed adult, ready to bite (courtesy of Monmouth County Mosquito Extermination Commission).

3) What is a vector, and why have scientists classified mosquitoes as one?

A vector is any insect or arthropod, rodent, or other animal of public health that is capable of harboring or transmitting a disease to humans. A mosquito is considered a vector because certain species can carry and transmit viruses like:

· West Nile Virus
·St. Louis Encephalitis (the virus Southern California is predominantly concerned with)
· La Crosse Encephalitis
· Eastern Equine Encephalitis
· Western Equine Encephalitis
· Malaria

4) Where are the vector mosquitoes generally located?

Habitat and climate determine which mosquito species will be present in any area. Vector mosquitoes are located in one specific relative to non-vector mosquitoes. For example, the Anopheles mosquitoes, that transmit malaria, breed in permanent bodies of fresh water.

5) Do all mosquitoes bite?

No, male mosquitoes do not bite, but female mosquitoes do. The female mosquito is the only one who bites. In essence, the female mosquito needs a blood meal, as food, to obtain the protein necessary to fertilize and develop her eggs. The females of a few species may produce a first batch of eggs without this first blood meal. After a blood meal is digested and the eggs are laid, the female mosquito again seeks a blood meal to produce a second batch of eggs. Depending on her stamina and the weather, she may repeat this process many times without mating again. The male mosquito does not take a blood meal, but may feed on plant nectar. He lives for only a short time after mating. Poor guy!

6) How does the mosquito spread the diseases that it carries?

It has been found that mosquitoes spread the diseases that it carries through a cycle. The cycle is known as the mosquito/bird cycle. The mosquito and the bird serve as host reservoirs, but humans and animals may be accidental end points. A bird-mosquito cycle keeps the transmission of the diseases going. The infected bird becomes immune in days, but another mosquito may feed on the bird when it is infectious. In the mosquito, the virus increases as much as a million-fold until it becomes a lethal injection. As the season progresses, mosquitoes are increasingly attracted to warm-blooded mammals such as horses and humans. These are "accidental" or "dead-end" hosts.

7) Have there been any major encephalitis outbreaks in Southern California? Is there a real danger?

There have been occasional outbreaks of St. Louis Encephalitis in Southern California. The most recent was in 1984. Of the 26 reported cases at the time, only one ended in death. While these outbreaks are relatively small, the danger of encephalitis in Southern California is real, and it is necessary to take measures against mosquito breeding and growth in order to prevent future outbreaks.

8) Is it possible, with future adaptations, that mosquitoes could carry the deadly HIV virus?

The HIV virus that produces AIDS in humans does not develop in mosquitoes. If HIV infected blood is taken up by a mosquito the virus is treated like food and digested along with the blood meal. If the mosquito takes a partial blood meal from an HIV positive person and resumes feeding on a non-infected individual, insufficient particles are transferred to initiate a new infection.

There has been some concern about whether mosquitoes are capable of transmitting AIDS from an infected person to an uninfected person with future adaptations. Unlike encephalitis viruses and other mosquito-transmitted diseases, the HIV virus that causes AIDS is not able to survive inside the body of the mosquito. Essentially, barring some never-before-seen genetic adaptation, it is virtually impossible that a mosquito could transmit AIDS.

9) What attracts mosquitoes to animals?

Mosquitoes are apparently attracted to host animals by moisture, lactic acid, carbon dioxide, body heat, and movement. The mosquito's hum results from the high frequency of its wingbeats; the female's slightly lower frequency may serve as a means of sex recognition.

10) How can an individual control and prevent mosquitoes around his/her home and how do you prevent disease outbreaks?

· Eliminate standing water in low spots, ditches, gutters and similar areas.
· Empty weekly or remove receptacles that collect rainwater (bird baths, old tires).
· Mosquito netting and tight screens can provide mosquito-free areas.
· Some mosquitoes are attracted to lights. Reduce unnecessary lighting to make yards less attractive.
· "Bug zappers" do not reduce mosquito landing or biting. They attract and kill many insects but few are mosquitoes that attack humans.
· Many of the insects killed are beneficial because they feed on garden pests.
· Ultrasonic devices, such as those that claim to mimic dragonflies, do not affect mosquito activity.
· Light-colored clothing is less attractive to adult mosquitoes. Tightly woven fabrics give some protection against biting.
· Deet and 6,12 are effective mosquito repellents.
· Highly concentrated versions of these products are available but low concentrations usually are just as effective and safer for children. Citronella and "Avon Skin So Soft" can be used for short periods of relief.
· Some naphthalene products (such as "Mosquito Beater") can be broadcast in yards for temporary relief from adult mosquitoes.

11) How does one control a population of insects that have the capability of flying away? How can you assure accuracy in pesticide sprays? What is the success rate for chemical control of mosquitoes?

The viruses associated with mosquitoes are controlled by a combination of surveillance and pesticide application. In Orange County, wild birds are monitored at 11 sites to check for incidences of encephalitis and other arboviruses. If blood samples from these birds test positive in five to ten percent of cases, the likelihood of human spillover increases. Current levels of one percent or below are considered safe. The most important way of controlling these viruses is controlling mosquitoes. Mosquitoes are controlled by pesticide applications and mosquitofish, which eat mosquito larvae. The chemical used to kill adult mosquitoes is Bacillus Thuringiensis Israelensis or BTI. It is a bacteria discovered in the Negev of Israel that kills mosquitoes, but does not harm other wildlife. IGH, or Insect Growth Hormone, has also been used to control mosquito populations. This hormone prevents mosquitoes from becoming adults, thus eradicating procreation and the need for a "blood meal."