The World Health Organization warned that with tuberculosis increasing worldwide there was a small but real risk of catching the disease on flights over eight hours long, AP reported. ``In-flight exposure to infectious tuberculosis in co-passengers has become a realistic airline possibility owing to the high prevalence of tuberculosis in some regions,'' said Dr. Claus Curdt-Christiansen, a member of a special WHO panel. The WHO report said there were no cases of passengers catching the disease itself on a flight with a TB-infected passenger. But it did cite cases when passengers caught the bacterium that causes the disease.

Solar radiation levels in Sydney and other parts of southern Australia have leapt by up to seven per cent, as the earth's protective ozone layer continues to weaken, it emerged this week. The dangerous increase in potentially lethal radiation coincides with Australian scientific research which confirmed that the ozone hole over the Antarctic this year was the biggest on record. It covered 25 million sq km, roughly five times the size of Australia.

Scientists now believe the increasing size of the ozone hole is having a direct impact on its protective function of shielding human beings from solar radiation. Australia already has the highest skin cancer incidence in the world. Several hundred people a year die from the condition and many more are forced to seek surgery for life-threatening melanomas.

Forty percent of deaths worldwide are caused by pollution and other environmental factors, and climate change will make matters worse, scientists say.

After studying population trends, climate change, increasing pollution levels and emerging diseases, 11 graduate student researchers led by Cornell ecology professor David Pimentel concluded: "Life on Earth is killing us."

Increased temperatures caused by global climate change will further encourage growth of human diseases and prod development of new illnesses, they wrote in the October 1998 journal BioScience.

They predicted that millions of people would become "environmental refugees," forced to flee their home areas in a desperate search for food.

"More and more of us are living in crowded urban ecosystems that are ideal for the resurgence of old diseases and the development of new diseases," wrote Pimentel, lead author of the report. "We humans are further stressed--and disease prevalence is worsened--by widespread malnutrition and the unprecedented increase in air, water and soil pollutants."

The researchers concluded: Each year, air pollutants adversely affect the health of 4-5 billion people, and the trend looks likely to worsen, with the number of automobiles growing three times faster than the rate of population growth. Lack of sanitary conditions contributes to 4 million deaths worldwide each year, mostly among infants and young children in developing countries.

Dr. Jeffrey Taubenberger would prefer if people refrained from hailing him as one of the century's great detectives. First, he is a man of science, a 38-year-old researcher whose view of the universe is usually limited to what can be seen through the viewfinder of his electron microscope at the U.S. Army's chief biological research facility at Fort Deitrich in Maryland. And second, as he ruefully admits, he is still a long way from cornering one of history's most remorseless and uncaring killers.

His quarry is a complex tangle of DNA strands that he hopes will allow him to understand the lethal nature of what an earlier generation dubbed the Spanish Lady, the pandemic of so-called Spanish Influenza that swept the world in 1918.

Though it is impossible after all these years to be precise, the Spanish Flu is thought to have claimed perhaps 60 million lives in just seven months before vanishing as quickly and mysteriously as it arrived. In India, 60 million people are thought to have perished. In San Francisco, the death toll rose so rapidly that the famous streetcars were used as hearses and the local paper noted that the city's teeming slums were "now beset by the stench of death." In Montreal, bodies were buried in bedsheets because undertakers could not meet the demand for coffins.

As in all the best detective yarns, Taubenberger and the small band of researchers who share his obsession have only a shadowy idea what their phantom looks like, and just a few tantalizing clues. What he does know beyond any shadow of doubt is that, in one form or another, the Spanish Lady will be back. And this time there is every grim reason to believe the death toll could be much, much higher.

Taubenberger's biggest fear, however, is that time is running out. "Influenza outbreaks involving major new strains tend to occur in 30-year cycles," he noted recently. "The last major outbreak was the Asian Flu in 1968, which killed about 40,000 people in this country. So do the math: If it's a 30-year cycle, we're getting very, very close to seeing the appearance of another totally new strain of influenza.

"It would be like 1918. No one would have immunity to this kind of virus and it really would spread all over the world. In 1918, in an age of steam ships, the virus raced around the world in months," he said. "In this era of jet travel, it won't be months--it will be days. Time is the one thing we lack."

A massive "dead zone" in the Gulf of Mexico, caused by toxic red tides, is a floating time bomb that experts say threatens waterfowl, commercial fishing and tourism. There is no life in the 3,000-square-mile zone, which was discovered several years ago. Caused by Gymnodinium breve red tides, experts say it threatens 75 percent of North America's waterfowl residing in the area. It also imperils nearly 40 percent of all U.S. commercial fishing, which yields 2.5 billion pounds of fish and shellfish annually.

Recent pest infestations in China have destroyed millions of acres of forests, causing at least $602 million in losses of timber every year, the state-run China Daily reported. The State Forest

Administration said that forests in China's northern, eastern and southwestern regions are dealing with a "massive bug plague," the newspaper said. Pine and poplar species were hit especially hard, with almost 20 million acres of forests damaged each year.