March 25, 2014 | 6
A cholera epidemic has infected more than 700,000 people and killed over 8,000 in Haiti over the last few years, a country of just over 10 million people. Why did the epidemic strike Haiti, when the disease has been absent from that region for a century? And why has the outbreak been so difficult to control?
In January 2010, a powerful earthquake struck Haiti. Earthquake damage may have made the country more vulnerable to a communicable disease outbreak, but no cholera was reported until ten months later. An outbreak then spread rapidly from the Arbonite region across the Haitian part of the Caribbean island that it shares with the Dominican Republic.
Cholera spreads via contaminated drinking water or direct contact with the Vibrio cholera bacteria in human fecal material from infected individuals. Typically, about 20 percent of infected people become severely dehydrated. Treatment with oral rehydration fluids, popular from the 1970s forward, has reduced death rates in most outbreaks to about 1 percent. But conditions in post-earthquake Haiti made it even more difficult than usual to reach isolated communities and treat patients, which raised the death rate far higher.
There had been no cholera in Haiti at least 100 years. But considering the existing infrastructure in the poorest country in the Americas, this should have provided little comfort to Haitian health authorities. Writing in Nature 2010 and 2011, Declan Butler offered succinct answers to the public health question, why Haiti? (Scientific American is part of Nature Publishing Group):
Haiti presented the perfect environment for a cholera epidemic. It awaited only the introduction of the pathogen. Haiti, like many low-income countries, could never afford and had never built a sanitary infrastructure to protect its citizens.
Over the last two centuries, science has taught us a great deal about cholera, but control of the disease in richer parts of the world has never depended on a sophisticated understanding of the organism, or on antibiotics and vaccines. Public health progress was achieved by controlling filth – by sanitary engineering. Communities with clean drinking water and properly treated human wastes are largely protected from rapidly spreading cholera.
Ironically, around 1900, public health practice suffered something of a setback from the understanding of communicable diseases generated by the new science of bacteriology. As it became possible to identify pathogenic microorganisms and their carriers, the focus of public health shifted from filth, infrastructure and sanitation, to blaming, chasing and isolating the carriers. It shifted from prevention toward treatment.
Fast-forward a century: It is not surprising that once cholera was detected in Haiti, many observers asked, “How did cholera get to Haiti?” As I wrote in an editorial for the Journal of Public Health Policy (published by Palgrave Macmillian, which is a sister company of Scientific American):
In the old days, health authorities might have found the physical source, like London’s Broad Street pump, but today even more could be learned about the source and who carried the pathogen to Haiti. Genetic typing made it possible to recognize that the strain afflicting Haiti came from Asia, most likely brought to the island by Nepalese soldiers working with the United Nations emergency response to the earthquake.
Very interesting, a triumph for laboratory methods that typed the pathogen! But once the disease was spreading, how cholera got to Haiti has offered little help in ending the outbreak or preventing future ones. The source didn’t much matter. Haiti’s abysmal sanitation infrastructure meant that Vibrio cholera, introduced from almost any source, could have caused an epidemic.
Yet many are now seeking compensation from the United Nations for illnesses and deaths. They blame the international earthquake relief operations for the epidemic. And perhaps the U.N. was negligent in the way it managed the human fecal waste of its people responding to the earthquake disaster.
For experts in public health this debate could be a dangerous distraction. The central question is: how are we going to protect people in low-income countries from the deadly risks they face due to inadequate sanitary infrastructure?
To their credit, the Haitian Ministry of Health and the National Directorate for Water Supply and Sanitation, understood how to control and prevent cholera. They kept their focus on sanitation and drinking water infrastructure even as they tried to control the ongoing epidemic. In 2011, the U.N.’s Independent Panel of Experts on the Cholera Outbreak in Haiti reported:
To prevent the spread of cholera, the United Nations and the Government of Haiti should prioritize investment in piped, treated drinking water supplies and improved sanitation throughout Haiti. Until such time as water supply and sanitation infrastructure is established:
(a) Programs to treat water at the household or community level with chlorine or other effective systems, hand washing with soap, and safe disposal of fecal waste should be developed and/or expanded; and,
(b) Safe drinking water supplies should continue to be delivered and fecal waste should be collected and safely disposed of in areas of high population density, such as the spontaneous settlement camps.
As noted in my editorial for the Journal of Public Health Policy:
In 1991, Dr. Robert Knouss, who was serving as the Deputy Director General of the Pan American Health Organization, appeared before a committee of the U.S. Congress to testify about the cholera epidemic in Peru that threatened to spread across Latin America. ‘What would it cost to eliminate cholera in the Americas?’ he was asked. He had not prepared for just that question, but his answer was quick, if not precise: ‘$25 billion–enough to build modern drinking water and sewage systems for every major city in the region that lacks one today’. (The number would be far larger in today’s dollars.)
Populations around the world who live without potable water and proper management of human fecal waste remain dangerously vulnerable. We shouldn’t be distracted by how cholera got to Haiti. Instead, we should urge the United Nations and donor programs that contribute money to build infrastructure to learn the lesson of prevention. Think as the late Dr. Knouss did. Invest now in water and sanitation before you are ‘surprised’ by an epidemic of cholera or other waterborne diseases, from any source.