By Andrew D. Smith
The Dallas Morning News
Copyright 2006 THE DALLAS MORNING NEWS
It started as a mild cough and worsened by the hour. What seemed like a chest cold was soon misdiagnosed as pneumonia. Four days after the first symptom, Donnie Dunavant went to the hospital.
And there he remains, more than two weeks after paramedics wheeled the 59-year-old from his Garland home.
Mr. Dunavant is one of 10 confirmed human cases of West Nile disease this year. At the same time last year, there had been none.
Public health officials expected a lot of West Nile virus this year, but not the numbers they’ve seen.
“Virus levels are so high right now, it’s unbelievable,” said Scott Sawlis, entomologist for the Dallas County Health and Human Services Department. “We’re finding four times as many infected mosquitoes as last year, and we’re finding them all over the county. People need to take precautions.”
Experts such as Mr. Sawlis began sounding the alarm in the spring, when hot, dry weather produced an early surge in the Culex mosquitoes that most often carry West Nile.
The weather persisted. Running water stagnated into breeding pools. Culex numbers soared. Then the cycle began reinforcing itself.
Extremely hot weather persuaded many people to shift outdoor activities from midday, when Culex mosquitoes rest, to twilight, when the creatures search for blood.
The increasing use of “privacy landscaping” such as thick bushes blocked the spread of mosquito sprays and reduced killing range.
Worst of all, a leading entomologist says, the soaring Culex population spread West Nile so much that it threatens to jump to other mosquito species, of which there are dozens in North Texas and thousands worldwide.
“A lot of people think of West Nile as a mosquito virus or a human virus, but it’s really a bird virus. People mostly get it when bird-loving Culex mosquitoes can’t find a bird to bite and settle for human blood,” said Jim Olson, professor of medical entomology at Texas A&M University.
“If the virus becomes more common in other mosquitoes - mosquitoes that like to bite humans - we’re going to see a more cases of West Nile, and the virus does appear to be jumping to other mosquitoes. We’ve seen it up in Dallas County.”
West Nile already afflicts many times more victims than generally presumed. Though Dallas County confirmed 43 human cases last year, Dr. Olson suspects the true number may have been 100 times that. He also suspects that the virus could grow many times more common this year than last.
Fortunately, four of every five West Nile victims never notice any symptoms, and the vast majority of symptomatic patients suffer nothing worse than a mild flu.
It is only a tiny minority of victims — probably around 1 percent, mostly people with weakened immune systems — who endure the worst symptoms of West Nile: encephalitis, or swelling of the brain; and meningitis, swollen tissue around the brain and spine.
Even among those who develop such symptoms, the majority survive.
West Nile has probably infected thousands of people since it first appeared here in 2002. Fewer than 150 cases have been bad enough to get reported to and confirmed by the county Health Department. Eight of them have resulted in death.
Even for survivors, West Nile can be horrific. In addition to fever, headache, vomiting and a stiff neck, victims can experience radical personality changes, seizures, confusion, weakness that borders on paralysis and sleepiness that quickly deteriorates into coma.
And there are no direct treatments. Doctors can only treat the symptoms in hopes of delaying death long enough for the patient’s immune system to beat the disease.
Public health officials have similarly limited options.
“To some degree, the battle with West Nile was lost the second it reached this country,” said Jason Chessher, Garland’s environmental health manager.
“There are so many birds and so incredibly many mosquitoes that it would be nearly impossible for us to wipe it out. The only thing we can do is minimize human cases by monitoring the disease, educating the public and making tactical strikes against the mosquitoes.”
The county and cities set traps to track mosquito numbers and to gather mosquitoes for West Nile tests. Mr. Sawlis has set about 30 traps a week since August. Mr. Chessher, working only in Garland, has also set 30 traps.
As of July 19, the county had found West Nile in 113 batches of mosquitoes from 88 locations. Cases had been found in all but three of the county’s municipalities, but the disease has not spread out evenly across the county. To the contrary, diseased mosquitoes tend to appear in clusters, which can create clusters of diseased humans.
Mr. Dunavant, for example, may have become infected in a West Nile hotspot, a hotspot right around his mother’s house on Duke Street in Garland. Another Duke Street resident came down with what appeared to be West Nile a few days before Mr. Dunavant, who often worked in his mother’s yard.
Of course, Mr. Dunavant may have gotten the disease at his house, a golf course or anywhere else. Still, the possibility of two West Nile infections worried Duke Street residents.
“If I’m not in the hospital with my wife, I’m basically trapped in my house,” said Morris Branch, whose wife, Alene, had the second suspected case. “I can’t go out in the day because I’m afraid of the heat, and I can’t go out in the evenings because I’m afraid of the mosquitoes.”
Indeed, perceived helplessness multiplies the terrors of West Nile.
Dana Govender, one of Mr. Dunavant’s four children, now makes her kids slather on insect repellant before they leave the house. She knows the odds. She knows it’s unlikely that they will contract the disease.
Then she thinks about her father.
“It’s unimaginably terrible to watch a person go through this,” said Ms. Govender.
“They have him on a respirator to keep him alive. They’re not sure if his brain has been damaged, and they have no idea when, or even if, he will ever recover. We all feel completely helpless.”