Experts link Haiti cholera outbreak to human actions, foreign strain

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May 5, 2011 (CIDRAP News) – A report from an independent panel of the United Nations (UN) on the source of Haiti's cholera outbreak yesterday stopped short of blaming Nepalese soldiers at a UN peacekeeping base, emphasizing that a combination of factors led to the outbreak that has so far sickened almost 300,000 people.

The panel of four experts, who conducted an epidemiologic, water and sanitation, and molecular analysis, said Haiti's cholera outbreak began at a river tributary near an audited peacekeeping base that did have inadequate plumbing to prevent contamination, but that environmental contamination from a fecal source couldn't have spread without deficiencies in the country's water, sanitation, and health systems.

Suspicion about the role of the UN peacekeepers in the cholera outbreak was one factor that led to rounds of violent protests in Haiti, which is recovering from a January 2010 earthquake disaster. Controversy over presidential elections also fueled the unrest.

In December 2010 an epidemiologist sent by France to assist with Haiti's cholera outbreak who investigated the events reported that the Nepalese soldiers were the most likely source of the outbreak and that the outbreak started in an Artibonite River tributary near their base.

The group began its work in early January after its appointment by UN Secretary-General Ban Ki-moon. Their 32-page report is available on the UN's Web site. The panel was headed by Dr. Alejandro Cravioto, a Mexican citizen from the International Center for Diarrhoeal Disease Research in Bangladesh. The other members are Dr. Claudio Lanata from Peru's Instituto de Investigacion Nutritional, Dr. Daniele Lantagne of Harvard University, and Dr. Balakrish Nair from India's National Institute of Cholera and Enteric Diseases.

In a statement yesterday, Ban Ki-moon said he plans to convene a task force to study the report's findings "to ensure prompt and appropriate follow-up."

The experts said evidence "overwhelmingly supports" human activity as the source that contaminated the Artibonite River tributary with the cholera strain, which they said did not originate in Haiti. The outbreak strain is very similar, but not identical, to South Asian strains circulating in Asia, they reported.

Other factors that led to the spread of cholera throughout the country included:

  • High numbers of people who use the river for washing, bathing, drinking, and recreation
  • Agricultural workers who are exposed to river waters, especially those working in rice paddies
  • Lack of population immunity to cholera
  • Infected people who fled their communities, dispersing the outbreak

"The independent panel concludes that the Haiti cholera outbreak was caused by the confluence of circumstances . . . and was not the fault of, or deliberate action of, a group or individual," according to the report.

Though the group didn't specifically fault the UN peacekeepers, several of their recommendations for preventing future cholera outbreaks were aimed at UN mission personnel. They suggested that UN and emergency responders traveling from cholera-endemic areas receive a prophylactic dose of antibiotics before departure, be screened to confirm absence of asymptomatic carriage of Vibrio cholerae, or both.

Further, UN groups and others who respond to emergencies where cholera epidemics are occurring should receive prophylactic antibiotics, be immunized with oral vaccines, or both, to protect themselves and others, the experts recommended.

To prevent environmental contamination, the group recommended that UN installations worldwide treat fecal waste using on-site systems that inactivate pathogens before disposal.

Other recommendations focus on improving cholera case management, investing in water supply and sanitation improvements, exploring the role of vaccines to curb the spread of the disease, and promoting the use of molecular techniques to improve surveillance, detection, and tracking.

See also:

May 4 UN press release

May 4 UN independent panel cholera outbreak report

Dec 8, 2010, CIDRAP News story "Experts disagree on Haiti cholera source as cases near 100,000"

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