The Killers All Around

They can strike anywhere, anytime. On a cruise ship, in the corner restaurant, in the grass just outside the back door. And anyone can be a carrier: the stranger coughing in the next seat on the bus, the college classmate from a far-off place, even the sweetheart who seems perfect in every way. For wherever we go and whatever we do, we are accosted by invaders from an unseen world. Protozoans, bacteria, viruses -- a whole menagerie of microscopic pests constantly assaults every part of our body, looking for a way inside. Many are harmless or easy to fight off. Others -- as we are now so often reminded -- are merciless killers.

Humanity once had the hubris to think it could control or even conquer all these microbes. But anyone who reads today's headlines knows how vain that hope turned out to be. New scourges are emerging -- AIDS is not the only one -- and older diseases like tuberculosis are rapidly evolving into forms that are resistant to antibiotics, the main weapon in the doctor's arsenal. The danger is greatest, of course, in the underdeveloped world, where epidemics of cholera, dysentery and malaria are spawned by war, poverty, overcrowding and poor sanitation. But the microbial world knows no boundaries. For all the vaunted power of modern medicine, deadly infections are a growing threat to everyone, everywhere. Hardly a week goes by without reports of outbreaks in the U.S. and other developed nations. Some of the latest examples:

-- A Royal Caribbean cruise ship on a trip to Baja California returned early to Los Angeles last week after more than 400 passengers came down with an unidentified intestinal ailment. It may have been the reason one elderly man died. And just a few weeks ago, 1,200 disgruntled passengers were evacuated from the ocean liner Horizon in Bermuda because of the threat of Legionnaires' disease. Among customers on previous Horizon voyages this summer, there have been 11 confirmed cases of the potentially fatal pneumonia-like illness and 24 suspected cases. At least one victim died.

-- A Yale School of Medicine researcher is recovering from a rare and potentially lethal disease called Sabia virus. Before 1990, the illness was unknown to medicine. Then a woman in the town of Sabia, Brazil, died from a mysterious virus that had evidently been circulating in local rodents for years before making an assault on humans. Brazilian doctors sent samples to Yale, and a month ago the scientist became infected when he accidentally broke a container holding the virus. Health officials point out that it is not easily passed between humans, but some 80 people who came into contact with the man have been under observation.

-- More than 850 people have come down with cholera in southern Russia, and officials fear the disease could erupt into an epidemic. Cholera outbreaks were rare in that part of the world before the breakup of the Soviet Union, but collapsing health services and worsening sanitary conditions have fostered the disease. Shortages of vaccines, meanwhile, have led to an upsurge in diphtheria in Russia, and health experts have encountered cases of typhoid, hepatitis, anthrax and salmonella in neighboring Ukraine.