The United Nations warns epidemics will break out within days unless health systems in southern Asia can cope with tens of thousands of corpses and hundreds of thousands left homeless in the wake of the 9.0 quake-induced killer tsunami that struck 11 nations.

“This may be the worst national disaster in recent history because it is affecting so many heavily populated coastal areas, so many vulnerable communities,” said the U.N.’s Emergency Relief Coordinator Jan Egeland. “The longer term effects may be as devastating as the tsunami itself. Many more people are now affected by polluted drinking water. We could have epidemics within a few days unless we get health systems up and running.”

The crisis cuts across all human needs, say experts – water, sanitation, food, shelter and health.

“We’ve had reports already from the south of India of bodies rotting where they have fallen and that will immediately affect the water supply especially for the most impoverished people,” said Christian Aid emergency officer Dominic Nutt.

Some affected areas have had communications cut. Others are so remote it is impossible to know the extent of the damage.

Governments in all 11 nations hit by the killer waves are still trying to determine how many were killed in the devastation wreaked by Sunday’s quake and the tsunamis it caused.

But with relief officials warning of possible cholera epidemics and malaria, Dr. David Nabarro, head of crisis operations for WHO, told reporters in Geneva that “there is certainly a chance that we could have as many dying from communicable diseases as from the tsunami.”

Nabarro said the main threat to life now is communicable diseases associated with a lack of clean water and sanitation.

“The initial terror associated with the tsunamis and the earthquake itself may be dwarfed by the longer term suffering of the affected communities,” Nabarro warned.

Hospitals and health services already are overwhelmed and may not be able to cope with people who fall ill with disease, he said.

Relief organizations are distributing supplies over 11 countries in Asia and Africa, and the United Nations has said it will likely make its largest ever appeal for humanitarian funding in response to the disaster.

The hardest-hit countries are Indonesia, whose Aceh region was closest to the epicenter of Sunday’s earthquake; then Sri Lanka and Thailand.

The health of babies and young children is the greatest immediate concern. Estimates say one-third of those killed are children. Children are more at risk than adults from diseases that follow in the wake of polluted water, fractured sewers and exposure.

“Even simple diarrhea and chest infections can prove fatal,” said Dr. Vivien Walden, a health adviser to Oxfam. “In many places it is still raining and families do not have shelter. They have lost everything. They have no means of cooking and there is overcrowding. In these circumstances, children under five are very vulnerable.”

Both adults and children who sustained wounds risk infection and ulcers. Women, forced to wade through flood water, are at risk of vaginal infections. Tetanus injections may be given to some.

But the greatest public health risk is from the polluted water supply.

“Clean water, first and foremost, is the priority,” Dr. Walden told the London Telegraph. “The wells will be polluted. Among the first things Oxfam is providing are buckets to carry water and cooking equipment,” she said. Lack of electricity will compound the clean-water crisis if pumping stations fail.

Desalination will be necessary as the flooding was caused by sea water.

Chlorine is the most widely and easily used means of disinfecting drinking water and, after 30 minutes, deactivates 99.99 per cent of enteric bacteria and viruses.

The great fear following a serious disaster is of epidemics of cholera, dengue fever, malaria, hepatitis A or even measles.

They do not follow automatically. Infectious diseases such as cholera, hepatitis A and measles need to be present before they can be spread. With mosquito-borne diseases such as malaria and dengue fever, the insects and their larvae will have been washed away and need time to re-establish. If malaria becomes a problem, it will be likely to make its appearance in six to eight weeks.

However, people forced to live outside are at greater risk of mosquito bites and overcrowding in relief centers makes the spread of infection easier.

“Hundreds of thousands of people fought to survive the tsunamis on Sunday. Now we need to help them survive the aftermath,” said UNICEF Executive Director Carol Bellamy. “We’re concerned about providing safe water, which is urgent in all these countries, and about preventing the spread of disease. For children, the next few days will be the most critical.”

A microbiologist in India said the risk of epidemics is very high because the decaying bodies are “bacteria factories.”

In India alone, hundreds of bodies lie in the streets and on beaches.

Steve Aswin of UNICEF said the bodies of the dead should simply be buried in mass graves, but there is often no one to do it.

UNICEF said it’s concerned about the possible spread of waterborne diseases and is sending anti-diarrhea medicine in its aid shipments.

“Safe drinking water is crucial at this juncture,” Bellamy said. “Where the flooding was the worst, local water supplies are contaminated and damaged. Without safe water, people will start drinking from unclean sources, and that will lead to disease. This is our No. 1 concern at the moment.”

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