As of Tuesday, the Vibrio cholerae bacterium has reportedly left more than 1,415 people dead in Haiti and 60,240 treated for dehydration since the outbreak started in late October. The Head of the UN Mission for Stabilization in Haiti (MINUSTAH), Edmond Mulet, told the Associated Press that UN experts were trying to determine the source of the cholera epidemic ravaging the country and took seriously the hypothesis that UN peacekeepers may have inadvertently contributed to the outbreak of the disease.
The Pan American Health Organization now estimates that the number of cholera patients in Haiti may reach 400,000 in the next year with "up to half of those cases occurring in the next three months," Dr. Jon Kim Andrus, deputy director of the organization, told reporters yesterday.
Watch this CNN video report from Haiti:
“For many of us here, this brings up memories of the cholera epidemic that began in Peru in 1991 and spread to more than 16 countries in the Americas within two years,” Andrus said. “Considering the intensity of travel and trade in the Americas, we know it’s difficult to prevent importations of isolated cases of cholera in other countries, but there are important steps that can be taken to prevent cholera from spreading and causing epidemics.”
In an interview with Discovery News, cholera expert Dr. Rita Colwell of the University of Maryland at College Park, and former director of the National Science Foundation, spoke about the endemic nature of cholera in the environment, how infections arise, and how to treat them.
“The bacterium is a native inhabitant of the aquatic environment,” she says. “The bacterium is naturally occurring in aquatic environments -- rivers, canals and especially in coastal waters.”
The bacterium attaches itself to the chitin shells on crabs, shrimps, and most notably the eurytemora copepod, a small zooplankton that is easy to filter out of drinking water using only a folded scarf or sari cloth.
“Richard Cash of Harvard 40 years ago showed that you need a million bacteria cells per teaspoon of water to come down with cholera. In water that has a lot of nutrients and is relatively warm, you can reach those numbers in sufficient quantity,” Colwell said.
Increased nutrients can come from street pollution or untreated sewage that is dumped into a river. Visible signs that the water is likely to carry the bacterium include abundant plankton, scum or other surface residues.
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"Dumping into the river is not a good solution, because what gets dumped upstream is the drinking water for people downstream. But similarly, high temperature and abundant plankton that in-and-of-itself can set off an epidemic -- that would be enough for an infection in drinking water without any filtration," Colwell said.
“Effective prevention is safe drinking water and sanitation and that has eliminated cholera from the United States, Canada, Western Europe and countries like Japan -- where 100 years ago we would have massive epidemics,” she said.
And while soap is a good step in the right direction, it is not enough. “Safe water and sanitation, those are the two components that will eliminate cholera,” she says.
In areas where sanitation is not available, the problem becomes cyclical as the infection travels from person-to-person.
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“Once an initial infection begins, it can be transmitted person to person,” Colwell said.
This is particularly the case for families caring for children who are vomiting and have diarrhea, she explained. To stop the spread of the infection it is imperative to have access to: soap, safe water for drinking and washing hands, proper latrines for disposal of feces, and a safe community-wide system for dealing with excretion.
The epidemic is the result of a “cascade of events,” she said. “You can’t pick out one thing, and, given that, solve everything.”
During his press conference Andrus added that “in the short term, efforts must focus on distributing chlorine tablets as well as oral rehydration salts to everyone. In the long term, we must create the systems and infrastructure to ensure equitable access to these basic services.”
Currently an estimated 1.6 million Haitians are living in "precarious conditions" where access to potable water is likely limited or non-existent.
For an earlier AFP report on this story, see also: Haiti Cholera Deaths Top 250
Tags: Everyday Science, Natural Disasters, Oceanography, Rivers, Safety
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