<img alt=“60773-haiti_300.jpg” src=“http://blogs.nature.com/nm/spoonful/60773-haiti_300.jpg” width=“300” height=“225” align=“right” hspace = “10 px”/>Last month, the United Nations released a long-awaited report indicating that human waste from Nepalese peacekeepers along with dirty drinking water likely triggered the spread of the cholera epidemic that has gripped Haiti since October, killing more than 5,000 people and sickening hundreds of thousands more.
The presence of foreign aid workers in the aftermath of last year’s earthquake, however, hasn’t been all bad. According to government officials, emergency response teams have helped contain the disease by providing clean water, medical treatment and sanitation systems. But with recent warnings that the numbers of people stricken with cholera could rise to 800,000 after the spring rainy season, global health experts say its time for a new approach to beat this infectious disease.
In a plan unveiled yesterday in PLoS Neglected Tropical Diseases, a team led by Paul Farmer, chief of the division of global health equity at Brigham and Women’s Hospital in Boston and a founder of Partners in Health, called for improved case detection, more aggressive treatment strategies and cleaner public water supplies to curb the spread of the disease.
“It’s important to recognize that we are losing the battle,” study co-author Edward Ryan, director of tropical medicine at the Massachusetts General Hospital in Boston, told Nature Medicine. “There has to be the use of new tools and old tools in new ways.”
Notably, the 44 experts behind the plan called on public health officials to put in place preventative measures to contain the epidemic, including immunizing the Haitian population with existing cholera vaccines.
Critics argue that such interventions do not provide sufficient protection to contain the disease during large outbreaks, and that, with fewer than 400,000 doses available, mass immunization is simply not a practical option for the Caribbean island nation. But in the report, the study authors point to several recent studies showing that rolling out vaccines during outbreaks could save thousands of lives. What’s more, they note that the global multimillion dose stockpile needed to kickstart the response to the outbreak could be amassed through advanced market commitments.
“What we are seeing now is a different cholera that has the ability to create protracted epidemics,” says Peter Hotez, an infectious disease researcher at George Washington University in Washington, DC, and another co-author of today’s plan. “The use of the vaccine constitutes a public emergency measure.”
Adding to the rationale for early interventions such as vaccines, scientists from South Korea’s International Vaccine Institute in Seoul released a study yesterday showing how environmental factors could predict cholera epidemics months in advance. Reporting in the American Journal of Tropical Medicine and Hygiene, the Korean team found that rainfall totals and temperature changes strongly correlated with the likelihood and the severity of cholera epidemics in Tanzania. For instance, the researchers found that a 1°C increase in the average monthly minimum temperature was linked to a doubling of cholera cases during a four month period. The researchers argue that a forecasting system based on these environmental parameters should enable cholera-afflicted countries to rollout life-saving vaccines and put emergency health workers in place well before people get sick.
Image: Doctors Without Borders