As the crisis deepens after tsunamis battered southern Asia on December 26, 2004, relief efforts have focused on a threat that's potentially more devastating than the initial floods were: communicable diseases.

FIGURE. A Thai nurse leaves a rose at what has become called "The Wall of Love," a board with photos of people missing after the December 26 tsunami, at the Phuket Hospital on the hard-hit resort island in south-central Thailand.

As the death toll mounts and remote buildings are unearthed from debris, governments and relief workers fear the onset of diseases such as typhoid fever, hepatitis A, dengue fever, malaria, and cholera, all of which flourish in tropical climates when people are forced to sleep outside, water supplies become contaminated or destroyed, and roads turn into open sewers.

International relief groups have been quick to advise villagers throughout India, Indonesia, Sri Lanka, Thailand, and other affected countries to practice basic prevention, such as boiling or chlorinating drinking water and handling food properly. Also, contrary to popular belief, corpses do not transmit infectious agents (except HIV, which can live up to six days), and so burials appropriate to cultural and religious norms are encouraged. The World Health Organization details the threat of disease after massive flooding at http://www.who.int/hac/techguidance/ems/flood_cds/en/index1.html, as does the Centers for Disease Control and Prevention at http://www.bt.cdc.gov/disasters/tsunamis/humanitarian.asp.

Nurses from across the globe are in southern Asia to aid the hundreds of thousands of displaced people. And the USNS Mercy, which left San Diego on January 5 on what the U.S. Navy is calling "Operation Unified Assistance," will provide health care to displaced and ill people throughout the region. The 894-foot hospital ship, equipped with 250 hospital beds (and the potential to expand to 1,000 beds) and 12 operating rooms, houses 275 health care personnel.

The International Council of Nurses has set up a disaster relief fund (http://www.icn.ch/tsunami.htm), and the ANA is coordinating disaster relief on its Web site (http://www.nursingworld.org/news/disaster/projecthope.htm).

Relief workers face the dangers inherent in treating displaced and potentially infected populations, as well as other hazards such as land mines in Sri Lanka, which has been plagued by civil war, and Banda Aceh, Indonesia, a sprawling region of antigovernment activity and the epicenter of the massive underwater earthquake that triggered the tsunamis.