Fight the bite! Beware of mosquitoes!

Some of the viruses that are carried by mosquitoes include dengue fever, St. Louis encephalitis (SLE), Eastern Equine encephalitis (EEE), West Nile virus (WNV) and other non-viral diseases like malaria. In addition to being disease vectors, mosquitoes can cause major disruptions through their persistent biting during recreational and social activities.

"We have 10 preventive medicine technicians (PMTs) at NAS Jax but currently four are deployed right now. Our job here is to keep track of the mosquito population. Currently in Florida there's 11 different species of mosquitoes that we monitor," said HM1 Fred Turner of the base preventive medicine division.

A male and female mosquito captured on base are shown here. These mosquitoes will be tested for any diseases.

Mosquitoes belong to the family of flies called Culicidae. Culicidae and are small fragile insects that have six delicate legs and two wings covered in scales. The head of a mosquito has antennas that protect the long piercing, sucking mouthparts. The life cycle of these insect are complex.

Young mosquitoes are totally aquatic and the adult is terrestrial. The adult female returns to a water only for a short time to lay batches of eggs. Most mosquitoes move only short distances from their original breeding place but others will fly longer distances.

According to Lead Program Manager for Entomology HM3(AW) Alexis Delvalle, "Surveillance at NAS Jax is the key. We primarily use approximately six New Jersey traps to capture mosquitoes. These traps have a light bulb attached to the top of the lamp that lures the mosquitoes in. A fan unit then sucks the mosquito down into a bag. Once captured the mosquitoes are brought back to the lab and frozen in preparation for weekly testing. Pesticide spraying for mosquito control is contracted out."

On average, a female mosquito will live up to three weeks with the male's

lifespan being shorter. Within their lifetime, both adult male and female will feed on nectar and plant fluids, but it is the female seeking a blood meal. Blood provides a protein source for egg development. "Different types of stimulants attract female mosquitoes to bite. The attractions include carbon dioxide and different body odors put off by the body," stated Delvalle.

After the female mosquito locates a desirable host, she will probe the skin for a blood capillary and then inject a small amount of saliva which contains chemicals. The saliva prevents the host's blood from clotting. Usually this is the way viruses enter the body of a host. After engorging on blood. the female will find a resting place to digest her meal and develop eggs. She will then fly off and lay them in an aquatic environment.

"We haven't had any cases of diseases here on base. In fact, until recently we just haven't had any rain. The mosquitoes need the water to breed. Mosquitoes haven't been a problem yet this year, but we are keeping an eye on the traps for any increase in activity," commented Delvalle.

Most people have only a mild sensitivity to mosquito bites but others can have a severe reaction from the saliva. Typical symptoms may include swelling, redness and irritation. If the bites are scratched they may become infected with bacteria and this can lead to a secondary infection.

One of the most well known viruses is the WNV. This virus has not been detected on base however WNV can cause serious, life-altering and sometimes even fatal side effects. It only takes one mosquito bite to transmit WNV. "Ways to prevent the spread of mosquito-borne diseases include using mosquito repellents with Permethrin and eliminating breeding sites," stated Turner.

You can also help reduce the number of mosquitoes in outdoor areas by weekly emptying stagnant water from flowerpots, pet food dishes, birdbaths and buckets. This can help reduce the number of places mosquitoes breed and lay their eggs.

For additional information on mosquitoes and the diseases they carry, contact Preventive Medicine Division at 542-3500, Ext. 8822.