A tiny bite from the winged mosquito poses a serious health threat to certain animal species, human beings being one. The threat is West Nile Virus (WNV), and summertime is the season when mosquito protection is most needed.

According to the South Carolina Department of Health and Environmental Control (DHEC), most areas of the United States are now at risk for human cases of West Nile Virus. First documented on the East Coast of the United States in 1999, WNV has now spread to the Pacific Coast as well as into Canada, Mexico and parts of the Caribbean and has now been recognized as a worldwide infectious disease.

A recent DHEC report indicates there were 4,156 human cases of WNV in the United States in 2002, and nearly 300 deaths. Also, more than 14,500 veterinary caes were reported.

While South Carolina had six reported human cases of WNV in 2003, only one case was reported in Orangeburg County. No cases have been reported so far this year.

"The emergence of West Nile virus underscores the need to avoid exposure to mosquitoes," said Dr. John Samies, infectious disease specialist at The Regional Medical Center (TRMC). Although no cases of WNV have been reported in Orangeburg County this year, the possibility exists, so precautions should be taken, such as ridding the environment of standing water and using insect repellent as recommended by the manufacturers."

Classified as an arbovirus, WNV is transmitted to animals and humans by the bite of an infected mosquito. Mosquitoes get the virus by feeding on infected wild birds, the host species for WNV.

About 10 to 14 days after the mosquito is infected, the virus can be transmitted to a human being or an animal. Symptoms of WNV develop in humans 3-14 days after a mosquito bite.

"The chance that any one person is going to become ill from a single mosquito bite remains low," said TRMC employee Sonya Kay Ehrhardt, TRMC registered nurse and infection control professional. "However, an estimated 20 percent of people who become infected will develop mild symptoms (West Nile Fever) that may include fever, headache, tiredness, body aches, nausea/vomiting, a skin rash (occasionally) on the trunk of the body and swollen lymph glands. Symptoms generally last a few days. Symptoms of severe disease may last several weeks."

Research shows that approximately 80 percent of people who become infected with WNV do not have any symptoms at all. There is no treatment for West Nile Fever, and the illness is generally mild and will go away by itself without causing long-term side effects.

About 1 in 150 people who become infected with WNV may develop more severe illness, such as West Nile encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes surrounding the brain and spinal cord). As a result, long-term disability can occur, and about 10 percent of those with severe disease will die. Symptoms of severe disease may include severe headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness and paralysis.

While anyone can become infected with WNV, people over age 50 are more likely to develop severe illness. Because studies also indicate that people can get the virus through blood products and transplanted organs from infected donors, all blood donations in the United States are carefully screened.

If a person develops severe disease, hospitalization is usually required for intensive supportive therapy, such as intravenous fluids and respiratory support. Long-term physical and occupational therapy may follow.

"People are advised to seek medical attention immediately when they become ill if they suspect they have been infected," Dr. Samies cautioned.

Unfortunately, there is no WNV vaccine for humans, and the only vaccine currently available is for horses and other equine animals. The main way to reduce the risk of infection of WNV is to avoid mosquito bites through various preventive measures. To reduce the risk of infection:

-- Apply insect repellent containing DEET, the most effective and best-studied repellent available, while outdoors. DEET can be used directly on the skin, and use enough repellent to cover exposed skin and clothing when outdoors. Always follow package directions for applying any type of insect repellent and assist children with application.

Be sure to wear long-sleeved shirts, long pants and socks sprayed with repellent while outdoors and install window and door screens to help prevent mosquitoes from coming indoors.

Types of control efforts include:

-- Larviciding - Using products to control immature mosquitoes.

-- Adulticiding - Using chemical products to kill adult mosquitoes.

-- Water control - Because mosquitoes lay their eggs in water, eliminate places where water can collect around the home by doing the following:

1. Empty water from items such as flowerpots, buckets, cans and pool covers.

2. Discard or cover stored tires and items not being used.

3. Unclog rain gutters and clean them when necessary.

4. Be sure stored water and wells are covered.

5. Clean pet water bowls each week.

Research continues on WNV, and health authorities are striving to make people aware of the causes and prevention of the disease. The Division of Vector-Borne Infectious Diseases of the Centers for Disease Control and Prevention, the Rotary Clubs of Fort Collins, Colorado and MediaTech have formed a partnership to address the risks posed by West Nile Virus. In an effort to educate the public about West Nile Virus, a video and CD-ROM production is available to Rotary Clubs, government agencies and others across the United States. To obtain information about the production package, go to maury@mediatechproductions.com and go to www.rotary5440.org/fortcollinsco/WESTNILEVIRUS/ or visit www.cdc.gov/westnile for additional information about WNV.

Preventive measures are highly recommended at this time of year to protect families and communities."

"Help your community by reporting dead birds to assist health departments track WNV," Ehrhardt stated. "Do not handle dead birds with your hands and contact DHEC immediately if you find one, especially blue jays and crows. Stay inside at dawn, dusk and early evening. And be sure to use insect repellent when outdoors."

T&D Staff Writer Sonja Gleaton can be reached by e-mail at sgleaton@timesanddemocrat.com and by telephone at 803-533-5523.

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