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                Texas Health Officials Study West Nile Outbreak

   by Greg Flakus

   AUSTIN, Texas -- Officials in the southwest U.S. state of Texas are
   tracking the spread of the West Nile virus, which has killed 21 people
   in the state so far this year and has sickened nearly 700. While the
   Dallas metropolitan area has had the most cases, the disease is
   cropping up all across the state.

   Technicians in the state's mosquito laboratory are examining mosquito
   corpses sent from all over Texas, at the Texas Department of Health
   Services Laboratories in the capital of Austin.
   State Laboratories Director Grace Kubin said technicians use animal
   tissue that is susceptible to West Nile virus to test the mosquito
   samples.
   "We add in, essentially, the ground-up mosquitoes," said Kubin. "We
   have to grind them up; that releases the virus. And now we have that in
   a liquid form and we can use that to infect the cells."
   Kubin said the tests provide results within 48 hours so the lab can
   advise local officials on what action to take.
   Mosquitoes aren't born with West Nile virus. They generally get it from
   biting birds that are infected.
   Right bird, right time
   To ingest the virus, mosquitoes need to find, so to speak, the right
   bird at the right time, according to Texas State Veterinarian Tom
   Sidwa. Some birds survive the virus.
   "The birds only have the virus remaining in their blood from one to
   four days after they get infected. Then they have life-time immunity,
   so you have to find that bird that has the virus in its blood stream,"
   said Sidwa.
   ''From the Austin command center, Sidwa manages the state effort to
   track the West Nile outbreak. He said his team got an early warning
   months ago from routine testing of donated blood.
   "This year we got advance notice that there was activity by virtue of
   that testing and people who were donating blood testing positive for
   West Nile. That does not mean they are sick. Some of them may be, but
   they have the virus in their system," he said.
   Most infected people unaware of it
   Sidwa said most infected people are unaware of it. Symptoms can include
   fever, headache and feeling tired. For the small percentage whose
   brains are affected by the virus, it can be debilitating and even
   deadly.
   "The way it manifests is everything from 80 percent of the people with
   no symptoms, to 20 percent with a lesser disease, and roughly one
   percent - or one in 150 - will develop the severe neurological form of
   the disease," said Sidwa.
   As the hot weather subsides in the weeks ahead, Sidwa said he expects
   the number of reported West Nile cases to taper off. And he said what
   has been learned this year will help in dealing with future outbreaks.
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   [1]http://www.voanews.com/content/texas_health_officials_study_west_nil
   e_outbreak/1494540.html

References

   1. http://www.voanews.com/content/texas_health_officials_study_west_nile_outbreak/1494540.html