Dead bodies cannot cause disease outbreaks, the Pan American Health Organization said Wednesday, hoping to avert mass burials of tens of thousands of unidentified victims from the tsunami in Asia and Africa.

There is no danger of corpses contaminating water or soil because bacteria and viruses cannot survive in dead bodies, said Dana Van Alphan, an adviser to the organization's Office of Emergency Preparedness and Disaster Relief.

She said it was important for survivors to be allowed to identify loved ones and urged authorities in tsunami-stricken countries to avoid burying unidentified corpses in mass graves.

"I think that psychologically, people have to be given the chance to identify their family members," she said. "Whatever disease the person has while still alive poses no threat to public health in a corpse."

Van Alphan warned, however, that rescue officials handling recently deceased bodies should wear gloves to avoid contact with blood. But she emphasized that any bacteria or virus in the blood would die almost immediately in the open.

The death toll across 11 nations passed 77,000, leaving officials desperate to dispose of decomposing corpses. Many officials already have resorted to mass burials, complicating efforts to identify victims and keep accurate death counts.

On Wednesday, officials in Indonesia's Aceh province bulldozed hundreds of bodies into pits, citing the smell and health concerns. No photographs of bodies were taken and no details of the corpses were recorded to help identify them later.

Officials in Indonesia — with a death toll at 45,268 — acknowledged they were making crude estimates, often taking the number of bodies in one mass grave and multiplying it by the number of graves.

Van Alphan urged officials to focus on providing clean water supply, saying the most immediate health threats were water-born diseases like cholera.

"I would recommend that the priority number one from public health point of view is to establish safe water supply," she said.