In the days after the Asian tsunami of 2004, the World Health Organization warned that the outbreak of disease following the disaster could result in as many as 50,000 additional deaths.
But the expected epidemics did not materialize, as aid organizations scrambled to provide clean water, treat the injured and deal with the dead bodies that heighten the risk of disease.
But in Haiti, disaster-response experts worry the lack of infrastructure could make it difficult to stave off a wave of dysentery and cholera, adding to the already wide-spread suffering.
"The next big fear will be the outbreak of diseases," said Stephen Brown, an expert in water-quality issues at Queen's University.
Access to clean water, antibiotics and basic health supplies are top concerns in the devastated island nation, said Giuseppe Annunziata, co-ordinator of the emergency response and recovery operations for the WHO, which is setting up monitoring systems so it can quickly respond to disease outbreaks.
Information on how the public can assist the relief efforts for the devastating earthquake in Haiti
Many believe the Haitian population is especially vulnerable. The country has long suffered from high rates of malnutrition, and less than half the population has any access to drinking water at the best of times. There was no public sewage system even before the earthquake. Nearly 200,000 Haitians have HIV or AIDS, and just half the childhood population is vaccinated against basic diseases like diphtheria.
"If there's a widespread outbreak of disease, the first line of defence is your own immune system," Mr. Brown said. "There's a lot of compromised people down there."
Aid organizations on the ground are scrambling to ensure survivors have access to safe water and sanitation to minimize the risks of diarrhea and hepatitis. Some groups are distributing chlorine tablets and personal hygiene kits.
Water filtration is one of the mandates of Canada's Disaster Assistance Response Team, which was deployed to Haiti this week. The naval ships headed to the island will also have on-board treatment systems.
After the tsunami and the 2008 earthquake in China's Sichuan province, Mr. Brown said priority was placed on getting water infrastructure into place to stave off disease. But in both those cases, resources could be easily delivered from other parts of the affected nations, and the countries involved had strong centralized governments and existing utility systems that could be repaired.
"In China, there was the possibility of getting industrial equipment in and roads that were still passable," he said. "There was the possibility of getting electricity back in the area in a reasonably short period of time. We'll have to see if that support work can be done effectively in Haiti."
But Avril Benoît, director of communications for Médicin sans frontières Canada said yesterday that despite Haiti's fragile state, the spread of disease was not an immediate threat.
"We are always concerned about it, keeping an eye on it," she told reporters. "There is no question that clean drinking water is a priority right now, but risks of disease spreading are seldom seen."