新研究或能预测哪里将出现霍乱疫情

Health officials are concerned that Hurricane Tomas could cause the cholera outbreak in Haiti to get even worse. The waterborne disease is already blamed for the deaths of more than 400 people there.

Before Tomas dumped a massive amount of rain on Haiti, doctors treated cholera patients in hospital tents. Flooding from the storm could cause cholera to spread as sewage and other refuse seeps into tents where many people have been living since January's devastating earthquake.

Cholera is a terrible new disease for Haiti, but conditions for its spread have been ripe for years. Haiti's public health infrastructure is weak, many people do not have access to basic sanitation, and especially in rural areas, people do not have clean drinking water.

Cholera causes severe diarrhea and dehydration. It can kill in a matter of hours. Dr. Peter Hotez, chair of the department of microbiology at George Washington University, says epidemoliogists were expecting cholera to breakout in Haiti. And once there, it is difficult to eradicate. "If you look where cholera epidemics have occurred over the last few decades, we know, for instance, that the disease is highly endemic, meaning it's there all of the time, in places such as India, Bangladesh and Pakistan.  So we know when there's flooding in Pakistan, we can expect cholera," he said.

Cholera is also prevalent in parts of Africa and Latin America, where seasonal outbreaks often occur. About 15 years ago, researchers at Harvard University Medical School discovered that cholera bacteria get infected with viruses.

Researchers now know that these viruses interact to make the cholera bacteria deadly. "It's the toxin that's causing all of the pathology associated with cholera infection and it's the toxin that we have to neutralize," he said.

This goal becomes more important as some strains of cholera become resistant to the antibiotics normally used to treat the worst cases. Researchers say these findings will help them predict when new types of cholera-causing bacteria will appear and start infecting people.