TACOMA -- In recent weeks, two local families have experienced firsthand the horrors of flesh-eating bacteria -- a little-understood disease that health experts say may be on the rise.

Eddy Anderson Jr. thought he was coming down with the flu, so he popped a couple of Tylenols. An emergency room doctor told Tom Chin he had pulled a muscle and recommended rest. Less than 48 hours later, both Tacoma men were dead, victims of flesh-eating bacteria -- or necrotizing fasciitis.

Although Washington state does not keep track of the numbers of those infected by the disease, the federal Centers for Disease Control estimates 500 to 1,500 cases occur in the nation each year. One in five victims dies.

Cases of the disease were less common prior to 1980, said Michael Curtis, an epidemiologist for the Washington State Department of Health. "Something about the organism has changed in the last decades, but at this point, what is anyone's guess," Curtis said.

The major culprit for the illness is the familiar streptococcus, the bug that usually causes no more than sore throats but that can pop up as scarlet fever and impetigo.   In its most dangerous form, strep penetrates the skin -- usually through a cut or scrape -- and destroys the victim's tissues from within.

It's not known what makes the bacterium so vicious once it penetrates the body's tissues. Theories include a more virulent strain of strep or an ordinary bug taking advantage of a weakened immune system.

For both, the first sign was a high fever, followed by severe muscle pain that made Chin flinch at the slightest touch and Anderson double over from pain.

It may have come in the blood of a traveler returning from Africa or Europe. It may have hitchhiked in an infected bird. There is even a slight chance that it came in the gut of a mosquito that flitted into a jet.

But as medical sleuths try to trace the path of the virus that has helicopters fumigating New York City and its suburbs, they are also confronting a much larger problem.

This virus, which has killed four people and scores of birds, is just one of dozens of hazards to people, crops, livestock, and wildlife that--after being hemmed in by oceans for millennia--are increasingly free to hopscotch the world because of the acceleration and growth of international travel and trade.

"In the modern age, this mechanical age, we think we've conquered the planet," he said. "But we're not quite the masters of the universe we think we are."

Smallpox accompanied seagoing European settlers to the Americas. But potato blight did not move from the Americas to Europe until the mid-1800s, when the advent of swifter ships allowed potatoes to arrive fresh, with the harmful mold healthy and alive. At the end of the 20th century, the explosive growth in airplane traffic has amplified the problem.

Britain's BSE (Bovine Spongiform Encephalopathy, or "mad cow disease") epidemic may have been caused by a scientific experiment that went wrong. The blunder has cost the country £4 billion, claimed the lives of 43 people, and triggered fears that the death toll could eventually reach several million.

Experts believe that hormones, taken from the brains of slaughterhouse carcasses, were injected into cows in a bid to create a new breed of super-cattle.

But the experiment--carried out in the Eighties--backfired. The hormones, extracted from pituitary glands, were transmitted in an agent that spread mad cow disease and eventually infected humans.

Twenty years ago a similar use of human growth hormone, extracted from the pituitary glands of cadavers and given to children with congenital dwarfism, was shown to have spread CJD (Creutzfeldt-Jakob Disease: the human equivalent of BSE) among humans.

"The theory is simple," said Dr. Anne Maddocks, a retired senior medical scientist who specialized in infection control at St. Mary's Hospital in London. "The promiscuous use of pituitary hormones in cattle led to BSE in the same way that they led to CJD in humans. The timing of the deaths in cattle and humans who were exposed to pituitary hormones is very compelling."

Although the ban on British beef exports was lifted in Europe, BSE specialists warn that the disease could still kill millions of people. Sir John Pattison, the chairman of the government's scientific advisory body on BSE, told the inquiry into the epidemic that it would take a decade to know the full impact of the crisis. "We, as a population, are in deep trouble," he said.

The Indonesian drought brought on by the 1997-1998 El Nino Southern Oscillation (ENSO) contributed to a serious malaria outbreak in the mountainous regions of Indonesia, according to a study presented Thursday at the 48th annual meeting of the American Society of Tropical Medicine and Hygiene. ``This malaria outbreak occurred in areas previously free of malarial disease,'' said Lieutenant Commander Michael Bangs from the US Naval Medical Research Unit in Jakarta, Indonesia, in an interview with Reuters Health. ``Above (elevations of) 1600 meters, malaria was not thought to pose a serious threat.''

The El Nino-associated drought, he said, contributed to the outbreak in at least three ways. First, the lack of sufficient food compromised the population's nutritional status, making them more susceptible to infection. Second, previously fast-moving streams dried up, leaving stagnant pools where mosquitoes could proliferate. Third, the food and water shortages stimulated the descent of the population to lower elevations where they were exposed to the endemic malaria. According to Bangs, death rates during this 10-week period soared from a baseline of 6 per week to more than 200 per week. ''Most of the excess deaths were due to malaria,'' he said.

The louse, the pesky little creature that infests the heads of millions of schoolchildren every year, apparently is becoming resistant to the insecticidal shampoos used to control it. A recent Harvard University study indicates more than 200 lice taken from the heads of 57 children survived exposure to permethrin, the active ingredient used in the most popular anti-lice shampoo.

The Centers for Disease Control and Prevention finds that as many as 12 million people worldwide get head lice every year.

Deadly viruses may be frozen beneath the polar ice caps and could unleash epidemics if they are released into the atmosphere, researchers told New Scientist magazine.

Scientists at Syracuse University in New York found a plant virus in the Greenland icepack which led them to believe that strains of influenza, polio and smallpox could be buried in icy tombs that could be opened by a warm spell.

"We don't know the survival rate, or how often they get back into the environment. But it certainly is possible," Tom Starmer told the magazine.

"If you've got these things lying in the ice for a thousand years or more and their usual host has not had to deal with them, this may be a source of epidemics," said Alvin Smith, a virologist at Oregon State University.