TV cameras brought the pounding waves and broken souls into our living rooms, but none could capture the next awful threat for Asia: a massive onslaught of infectious disease. The fears of local health officials and villagers who rushed to bury the dead were unfounded; corpses do not spread illnesses. The real risk for the survivors of this disaster are age-old pathogens that sneak into the human gut, bloodstream and airways through contaminated water, mosquitoes and contact between living people. Even without widespread flooding, infectious diseases run rampant in developing countries, which often lack the basic necessities for public health: clean water, efficient sewer systems and well-stocked clinics and hospitals. Every year cholera strikes tens of thousands of people, mostly in Africa and Asia, and malaria kills more than 1 million. Too often, it is the young and the poor who suffer most: the vast majority of malaria victims are children, and 2 million children under the age of 5 die from pneumonia annually. Now in the tsunami's aftermath, global health experts worry that the dangerous microbes already lurking in underdeveloped regions of Asia will spread exponentially, pushing the tsunami's enormous death toll even higher.

In a vast effort to tackle the diseases head-on, the World Health Organization and other aid groups are sending water-purification tablets and dozens of huge emergency health kits to Asia capable of serving 10,000 people for up to three months. Among the contents: rehydration salts, antibiotics and antimalarials. Can they ward off epidemics? The next few weeks will tell. For now, says Dr. Koen Henckaerts of Doctors Without Borders, "you try to save as many people as you can in the shortest time possible." The most likely dangers:

CHOLERA: Had the tsunami hit Los Angeles, cholera would not be a concern. "It's rare, if not impossible, for disease to appear out of nowhere," says the WHO's Gregory Hartl. But in countries where drinking water and hygiene are compromised even in the best of times, cholera--and other diarrheal diseases like dysentery, typhoid and shigellosis--can proliferate. Those hit hardest by cholera, a toxic intestinal infection, can lose as many as two gallons of body fluid a day. It is logistically impossible to ship enough bottled water to large-scale disaster sites; instead, relief teams purify local water. First, in a process called "flocculation," they add a solution that clusters dirt particles together so they can be filtered out. Then they mix in chlorine to destroy the germs. If cholera has already struck, oral rehydration salts or intravenous therapy can cure it. Without treatment, however, the bacteria is so lethal--dehydration can kill within hours--it ranks as a potential biological weapon.

MALARIA: Giant floods leave pools of stagnant water in their wake--a prime breeding ground for the mosquitoes that carry malaria and other "vector-borne" diseases like dengue fever, which cause fever, vomiting, chills, muscle aches and, in the worst cases, death. The chance of exposure increases when stranded people spend day and night outdoors. Health officials are taking no chances, shipping the most potent antimalarial treatment, Artemisinin-based combination therapy or ACT, to target areas.

PNEUMONIA: Many of the millions displaced by the tsunami will be forced to take up shelter in the cramped quarters of make-shift tents, where respiratory illnesses, like influenza and pneumonia, can spread rapidly through close human contact, coughing and sneezing. While cholera and other water-borne diseases are by far the No. 1 concern in Asia, doctors say they must be vigilant on all fronts. Small children and the elderly are especially susceptible. Treated promptly with antibiotics, which are now making their way to remote areas, pneumonia--and its accompanying cough, fever and chest pain--can be cured.

Amid all of the uncertainty and worry, doctors say there is virtually no risk of any of one of these infectious diseases spawning a global pandemic. Still, says Dr. Howard Markel, author of "When Germs Travel" and professor at the University of Michigan, "we can never really get rid of germs, we can only wrestle them to a draw." Let's hope the doctors can somehow win the fight in Asia.