Mosquito bites cause itching and irritation, and scratching may result in infected sores. Mosquitoes also transmit serious and sometimes fatal diseases to humans and their pets. Encephalitis is an inflammation of the brain that can be caused by viruses. Symptoms of encephalitis can range from mild to severe. Symptoms include rapid onset of severe headaches, high fever, and mental disturbances such as confusion, irritability, tremors, stupor and coma. Severe cases sometimes end in death or with survivors suffering permanent loss of limb function, reduction of intelligence and/or emotional instability.

Not all types of encephalitis viruses are carried by mosquitoes. However, mosquitoes carry at least two types of encephalitis viruses that cause human disease in Texas. West Nile and St. Louis encephalitis are normally an infection of wild birds but can be passed to other mammals by mosquitoes; in humans both viruses affect mainly individuals over 50 years old or those with weakened immune systems.

Mosquitoes can also infect dogs with heartworm. The worms live in the heart and can severely weaken or kill the dog. Although difficult to treat, this disease is easily prevented by medication that can be prescribed by your veterinarian.

All three of the viruses mentioned above are transmitted by a species of Culex mosquito. Culex mosquitoes, which breed in places like ditches, open septic systems, discarded tires, unused pools, and other assorted containers, particularly in shady areas. Mosquito larvae or "wrigglers" must live in still water for five or more days to complete their growth before changing into adult biting mosquitoes capable of transmitting disease. Often, the number of mosquitoes in an area can be reduced by removing sources of standing water. Hundreds of mosquitoes can come from a single discarded tire and thousands from an untreated swimming pool.

Mosquito-Proof Your Surroundings

• Get rid of old tires, tin cans, buckets, drum, bottles or any water-holding containers
• Fill in or drain any low places in the yard
• Keep drains, ditches and culverts free of weeds and trash so water will drain properly
• Keep roof gutters free of leaves and other debris
• Cover trash containers to keep out rainwater
• Repair leaky pipes and outside faucets
• Empty plastic wading pools at least once a week and store indoors when not in use. Unused swimming pools should be kept chlorinated weekly or treated with mosquito larvicide monthly
• Fill in tree holes and hollow stumps that hold water
• Change the water in birdbaths and plant pots or drip trays at least once each week
• Store boats covered or upside down, or remove rainwater weekly
• Keep grass cut short and shrubbery well trimmed around the house so adult mosquitoes will not hide there.
• Only a constant, complete program to control mosquitoes will reduce the numbers, the nuisance and the danger of disease

Protect Yourself From Mosquito Bites

Although many kinds of mosquitoes bite at dusk or at night, some kinds will bite during the day. Almost all kinds will try to bite if you enter an area where they are resting, like high grass.
When possible, avoid places and times when mosquitoes bite. Ways of minimizing likelihood of getting bit include:

• Wear light-colored protective clothing. Tightly woven materials that cover arms and legs provide some protection from mosquito bites. Keep trouser legs tucked into boots or socks, and collars buttoned
• Have good screening by making sure door and window screens fit tightly and all holes are repaired
• Use mosquito netting when sleeping outdoors or in an unscreened structure, and to protect small babies any time
• Small amounts of water can be treated for mosquito larvae with "Bti," a bacterial insecticide. Many hardware stores carry doughnut-shaped Bti briquettes (Mosquito Dunks R) for this purpose. Be sure to follow the insecticide label directions exactly
• When participating in outdoor activities where mosquitoes are biting, wear protective clothing (shoes, socks, shirt and long pants). For additional protection from mosquitoes, use an insect repellent. The more DEET a product contains, the longer the repellent can protect against mosquito bites. However, concentrations higher than 50 percent do not increase the length of protection. For most situations 10 percent to 25 percent DEET is adequate. Apply repellents to clothes whenever possible; apply sparingly to exposed skin if label permits. Consult a physician before using repellents on young children
• Spraying your backyard with an insecticidal fog or mist is effective only for a short time. Mosquitoes will return when the effect of the spray has ended
• Insect light electrocutors ("bug zappers") or sound devices do little to reduce biting mosquitoes in an area
• Installing bird or bat houses to attract these insect-eating animals has been suggested as a method of mosquito control. However, there is little scientific evidence that this significantly reduces the mosquito population around homes

What is West Nile virus?

West Nile virus is a mosquito-borne virus that can infect humans, birds, horses and other mammals. In most humans, West Nile virus infection causes a mild or moderate, short-lived flu-like illness, or causes no symptoms at all. However in some cases, particularly among persons 50 years of age and older, it can cause serious neurological diseases such as encephalitis, meningitis, or paralysis. West Nile virus first appeared in North America in New York City in 1999. Since then, the virus has spread across the continental United States. Visit www.cdc.gov for more information on West Nile virus nationally.

How is West Nile virus spread?

• Infected Mosquitoes. Most often, WNV is spread by the bite of an infected mosquito. Mosquitoes become infected when they feed on infected birds. Infected mosquitoes can then spread WNV to humans and other animals when they bite.
• Transfusions, Transplants, and Mother-to-Child. In a very small number of cases, WNV also has been spread through blood transfusions, organ transplants, breastfeeding and even during pregnancy from mother to baby.
• Not through touching. WNV is not spread through casual contact such as touching or kissing a person with the virus.

What can be done to prevent West Nile Virus?



Prevention is the best defense against West Nile Virus. Haltom City residents are reminded to enjoy the outdoors, and remember the Four D’s:

• Dusk and Dawn are the times of day you should try to stay indoors. This is when infected mosquitoes are most active.
• Dress in long sleeves and pants when you’re outside. For extra protection, you may want to spray thin clothing with repellent.
• DEET is an ingredient to look for in your insect repellent. Follow label instructions, and always wear repellent when outdoors.
• Drain standing water in your yard and neighborhood where mosquitoes can breed. This includes old tires, flowerpots, clogged rain gutters, etc. Mosquitoes may develop in any water stagnant for more than three or four days.

What are the symptoms of West Nile virus?


Most people who are infected with West Nile virus either have no symptoms (80%) or experience a mild or moderate illness with symptoms such as fever, headache, fatigue, or body aches before fully recovering. It is estimated that 20% of people who become infected with WNV will develop West Nile Fever. Of these, 1/150 persons may develop the more serious neuroinvasive West Nile.
Some persons may also develop a rash or swollen lymph glands. In some individuals, particularly persons 50 years of age and older, West Nile virus can cause serious disease that affects the brain and spinal tissue. Severe illness may include encephalitis (inflammation of the brain), meningitis (inflammation of the membrane around the brain and spinal cord), or acute flaccid paralysis (a polio-like syndrome in which muscles become very weak or paralyzed). Symptoms of more severe disease may include headache, high fever, stiff neck, nausea and vomiting, confusion, coma, tremors, convulsions, muscle weakness and/or paralysis. At its most serious, West Nile virus can cause permanent neurological damage and death. Among those people who need to be hospitalized for West Nile virus, 10-15% die of their illness. People who do develop symptoms normally become ill 3-15 days following the bite of an infected mosquito.

How is West Nile Virus treated?



There is no specific treatment for West Nile virus. Most people who become infected will get better on their own. In more severe cases, intensive supportive therapy is indicated, i.e., hospitalization, intravenous (IV) fluids and nutrition, airway management, ventilator support if needed, prevention of secondary infections and proper nursing care.



Who is most at risk for getting severe West Nile virus disease from being bitten by an infected mosquito?

• People over 50 at higher risk to get severe illness. People over the age of 50 are more likely to develop serious symptoms of WNV if they do get sick and should take special care to avoid mosquito bites.
• Being outside means you're at risk. The more time you're outdoors, the more time you could be bitten by an infected mosquito. Pay attention to avoiding mosquito bites if you spend a lot of time outside, either working or playing.
• Immunocompromised persons, such as persons who have received organ transplants.

How long does it take to get sick if bitten by an infected mosquito?

Most people who are infected with West Nile virus have no symptoms or experience only mild illness. If illness does occur, symptoms generally appear between 3 to 15 days of being bitten by an infected mosquito.

Can you get West Nile virus directly from birds?

There is no evidence that a person can get the virus from handling live or dead infected birds. However, persons should avoid bare-handed contact when handling any dead animals and use gloves or double plastic bags to place the carcass in a garbage can.



What is being done to protect residents against West Nile Virus?

The City of Haltom City relies upon surveillance, both by residents and City crews, to identify and eliminate any standing water which could serve as a breeding place for mosquitoes and larvae. Typically larvae will thrive in still, shallow water less than 15 inches deep. Bird baths, pet bowls, wading pools, tire swings or any similar receptacle with standing water can serve as a breeding place for mosquitoes.

Download PDF file detailing the West Nile Virus and what Tarrant County and Haltom City are doing to monitor and educate people about it.