Cholera in Haiti — The Climate Connection

http://www/circleofblue.org/waternews/2010/world/hold-cholera-in-haiti-the-clima...

After lying dormant in Haiti for half a century, a three-week-old cholera outbreak has killed more than 700 people and is advancing across the country. On Tuesday, the epidemic reached Port-au-Prince, Haiti’s capital and largest city, where more than a million people are still squatting in over-crowded tent camps and sharing scant latrines. Hurricane Tomás, meanwhile, struck Haiti’s shores on Friday, flooding vulnerable tent camps. Reported infections have climbed close to 10,000 cases — nearly doubling in the last week.

“I don’t think we are going to see the end of it any time soon,” Emmanuelle Schneider of the United Nations Office for the Coordination of Humanitarian Affairs told Circle of Blue. “It’s very contagious and it can spread fast.”

Cholera, a water-borne disease, can spread rampantly when clean water and proper sanitation are not available, as had been the case in Haiti long before the January earthquake that killed 250,000 and displaced 1.6 million. But the damage from the earthquake, which hit hardest in Port-au-Prince, could be the compounding factor that allowed cholera to rise from the rubble.

Researchers, health officials and the media are all seeking answers to the same question: where did the cholera bacteria come from?

The Centers for Disease Control and Prevention (CDC) reported that the strain of cholera that is spreading in Haiti originated in Southeastern Asia. That finding prompted news organizations to focus on humanitarian workers as the source of infection, an assertion that medical specialists quickly discounted. A handful of activists, in addition, blame the outbreak on Haiti’s substandard housing since the quake.

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“They have been fortunate in Haiti that for 50 years the conditions have been such that they haven’t had an intense increase in cholera bacterial populations,” said Rita Colwell, professor at the University of Maryland and former director of the National Science Foundation. “But they’ve had an earthquake, they’ve had destruction, they’ve had a hurricane. So the conditions would lead to a very high probability of an outbreak.”

She added: “I think it’s very unfortunate to look for a scapegoat. It is an environmental phenomenon that is involved. The reason we don’t know [the catalyst] is because the medical community is not receptive to climactic causation or correlation.”

The Climate Connection

Cholera is an intestinal bacterial infection spread by eating food or drinking water that has been contaminated.

Although rural areas experienced less damage from the earthquake, they were the first epicenter of the epidemic. The small communities along the Artibonite River, located 60 miles north of Port-au-Prince, have been using the river as a source of drinking and bathing water — until reports came that the river is the likely source of the outbreak.

“Cholera was originally in the Artibonite River,” Schneider said. “But people are very mobile, so they are moving from place to place, which is a trigger for the cholera epidemic.”

In the last few decades, great strides have been made in unlocking the riddles associated with cholera and seasonal climate patterns. Dr. Colwell was among the first to find that cholera epidemics flare up during the wet spring and fall seasons, when excess precipitation creates favorable environmental conditions such as increased salinity and warmer temperatures in areas already suffering from poor sanitation and lack of clean water access.

Colwell and her colleagues are studying 75 years of cycles in India and hope to have definitive parameters in the next few months. Additionally, using weather data from 1991-1992 and 1997-1998, they have shown that there is a correlation between cholera outbreaks in Latin America and El Niño climate patterns.

The intent of her research is to predict cholera outbreaks using the link between weather patterns, water surface temperatures and plankton blooms — all of which could be detected using remote sensing satellites. An early warning system for coastal dwellers would have been valuable for Haiti.

Afsar Ali, an associate professor of environmental and global health at the University of Florida, agrees with the environmental climate conclusion. He told the Tampa Bay News that the cholera outbreak is happening now, rather than immediately following the earthquake in January, because the water temperature is warmer. And since the first cases of cholera were reported in a coastal city, Ali believes that residents had longtime immunity, whereas the estimated 300,000 refugees who moved to the Artibonite region after the earthquake did not.


Even before the earthquake, there were risk factors for water-borne disease. More than 40 percent of Haiti’s total population did not have a source of reliable drinking water, according to a study by the United Nations. And nearly half of rural Haitians were defecating in the open, according to a joint study by the World Health Organization and UNICEF.

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Colwell, who this year was awarded the Stockholm Water Prize, has studied the link between cholera and climate for the last 30 years. Her research has disproven the long-held belief that cholera could only enter the environment due to a release of sewage, and has proven that there is a link between changes in the natural environment and the spread of disease.

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