Mad cow disease

Infection connection links animals, humans

Scientists keep a watchful eye on the trend of animal illnesses threatening humans.

[Times photo: Willie J. Allen Jr.]

Kairah Mosley, 3, rides a horse on her family's farm in DeSoto County last week. In September, she was hospitalized with West Nile virus.

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	• Book ties disease origins to modern developments

In the United States, the hunt is on for cows with brain-wasting mad cow disease.

On the other side of the world, civet cats are being slaughtered in China in hopes of preventing the spread of SARS.

And in Africa, scientists have linked the deaths of chimps and antelopes to human outbreaks of the deadly Ebola virus.

Everywhere, it seems, there's an animal illness suddenly threatening humans.

The trend is real. New infectious diseases have appeared, and old ones have re-emerged, all over the globe over the past several years. More new infections will "inevitably" appear, probably more often than in the past, concluded the influential Institute of Medicine in a report last year.

Most of those emerging diseases are transmitted to humans from animals.

"The interaction of man with animals is far more risky than at any time in the last 100 years," said University of South Florida medical professor John Sinnott, director of the Florida Infectious Disease Institute.

Sinnott and other scientists say global changes are influencing the spread of disease. Those trends range from something as seemingly insignificant as parents who buy an exotic pet for their child to the broader changes of clearing rain forests and modern agricultural practices, such as feeding animal products to cows.

Animal diseases concern officials at the federal Centers for Disease Control and Prevention so much that they have created a new post to address veterinary medicine and public health.

Nina Marano started that job Thursday. She says more research is needed on how illnesses jump from animals to humans and how disease outbreaks in animals might signal increased risk for a human epidemic.

"There's a need to have someone to work in the animal world and the human world," Marano said.

In the deep of a September night, 2-year-old Kairah Mosley came to wake her parents. She had a fever and didn't feel good. Her mother gave her Motrin, and Kairah went back to bed. The next day, the doctor said she had a virus, not to worry, and sent her home.

But two days later, Kairah's fever shot higher and higher, above 106, and her body went limp. Her terrified parents rushed her from their Fort Ogden farm to the hospital.

Kairah got worse. She couldn't see. Her mother, Kelli, watched her child call for her without seeing where her mother was.

Then Kairah lapsed into a coma-like state. Doctors sent her to All Children's Hospital in St. Petersburg.

It was there that Dr. Juan Dumois, All Children's chairman of infectious disease, gave her parents the news: Kairah had West Nile virus. Her brain was swelling. She might die.

"I couldn't believe it, that it actually happened," Kelli Mosley said. She had heard the warnings and had tried to protect her four children from the mosquitoes that spread the disease. "I would spray all of them down."

There had never been a case of West Nile in DeSoto County before.

Mosley couldn't even remember Kairah's getting a mosquito bite.

But somewhere, Kairah did.

West Nile came to Florida from New York, most likely in the bloodstream of infected birds. They, in turn, were bitten by mosquitoes that became infected and went on to infect all sorts of animals -- including humans.

The virus first showed up in Queens, N.Y., in 1999. How exactly it arrived there from the Mideast, where there have been waves of the illness for decades, will always be a mystery. That's because there are so many different ways the disease could have arrived, veterinarian Mark Walters says in his recent book, Six Modern Plagues and How We Are Causing Them.

Each month, John F. Kennedy International Airport brings 11,000 international flights and 2-million people through Queens. Add in the thousands of animals that come in legally, the animals that are smuggled in and the insect stowaways on overseas flights, and Queens is more than the JFK airport's slogan, "where America greets the world."

It's "one gigantic petri dish," said Walters, an associate professor at USF St. Petersburg.

The same rapid travel patterns helped severe acute respiratory syndrome break out last year from a province in China -- where people live in close contact with animals and eat relatively exotic meat, such as civet -- to become a global epidemic in a few weeks.

Such changes mean that public health scientists have to be more active and pay more attention to diseases around the world, said Dr. Paul R. Epstein, associate director of the Center for Health and the Global Environment at Harvard Medical School.

"We have to be concerned about the conditions in China and the conditions in the Congo," he said. "The emerging disease issue brings home our need to concern ourselves with ecologic change and climate change where disease can breed easily."

Everywhere you look, Sinnott said, people and animals are mixing more closely. In the northeastern United States, people are building homes on the edge of the woods, where the ticks that carry Lyme disease hitch rides on deer. In Africa, hunters bring back the meat of animals that scientists think may transmit Ebola, a usually fatal virus that causes massive hemorrhaging in its victims.

Even pets can be a risk. Last year's outbreak of monkeypox was linked to pet prairie dogs, who are thought to have been infected by a Gambian giant rat, also imported to become a pet.

At All Children's Hospital, a boy came in a few years ago with a fever and kidney and liver problems, Dumois said. The boy had symptoms of leptospirosis. The disease, caused by a bacteria that can infect several animals, is the most widespread animal-borne disease in the world.

Yet leptospirosis is rare in the continental United States, with only about 50 to 100 cases per year. Dumois had never seen a patient with the disease.

But the family had recently gotten a new pet -- a sugar glider, a type of gliding possum native to Australia. Dumois believes that's how the boy, who recovered, contracted the disease.

"I tell our (medical) residents, many times, what's most important is the history of the patients," Dumois said. "Part of that history is contact with animals."

In Asia right now, millions of influenza-infected chickens have died or been killed, in hopes of reducing their contact with humans. Different strains of flu are found in lots of animals, but only rarely has flu jumped directly from birds to humans.

Scientists fear that if such a bird flu began to spread among people, it would be more deadly and less likely to respond to a vaccine. That would set the stage for an epidemic widespread enough to rival the great Spanish flu of 1918, which killed more than 20-million people around the world.

Several people in Asian countries have contracted the flu directly from birds in recent weeks.

"You have practices of chicken raising close to where people live," said veterinarian Marano, who is a new associate director at the CDC's National Center for Infectious Disease. "Frequently, you have farmers with backyard chickens. As far as disease control, it's difficult when you have a small flock here and another flock across the fence."

World Health Organization scientists are investigating, and U.S. infectious disease scientists are watching nervously.

"This is extremely worrisome," Epstein said. "What is comforting so far is that there hasn't been person-to-person transmission" which would indicate that the virus had mutated into something more contagious. "We hope it will fizzle out."

Not all animal diseases are new. Some links, scientists point out, are a result of better detection. But they also point to other changing practices.

Feeding antibiotics to animals to make them grow faster has increased the number of dangerous germs that are resistant to antibiotics.

Changing habitats can force germ-carrying animals out of their natural homes. Walters points to a 1999 outbreak of Nipah virus in Malaysia, which occurred after fruit bats that carry the virus came to pig farms in search of fruit trees. They infected pigs, which infected people.

Even global warming contributes to animal outbreaks, Epstein and other scientists say, because changing climate patterns affect animal populations, which in turn can allow different germs to spread.

Historically, waves of disease have accompanied great social change, Walters says. Such changes included when humans first established agricultural settlements, when different civilizations began having more contact with one another, and when Europeans began exploring the Americas.

"We're probably in the fourth great wave of epidemics," he said. "Those were all choices -- changes we made to natural systems."

They all add up to more disease, Sinnott said.

"There are diseases we can't know about incubating, ready to break out," he said. "I worry not just that we'll see more, but that their severity will increase."

Kelli Mosley sat by Kairah's hospital bed, listening on the telephone as Kairah's twin brother, Kaimen, cried for his sister, whom he had nicknamed "Ray-ray."

Kairah had been in a coma-like state for a week. Her mother put the phone up to her daughter's ear. "Ray-ray," she heard Kaimen call. "Come home, Ray-ray."

Kairah opened her eyes.

It was, Mosley will always say, "a miracle moment." But Kairah couldn't talk or walk or even feed herself. She was like a newborn again.

Kairah returned home to the family's farm southeast of Sarasota in October. Over the next few months, she began talking again and gradually relearned to walk. In December, she turned 3.

Doctors tell her mother that Kairah's brain is still slightly swollen. It's too soon to tell whether there's any permanent damage. But her speech has mostly recovered, and if you didn't know, you might not notice her limp.

Kairah has started riding the family's horses and tending the farm calves. She plays with toy horses and has named one Tina, after an All Children's nurse.

But there's one creature that Kairah has no affection for.

"She'll tell you," Kairah's mother said, "A mosquito bite me and make me sick."'

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