In October of 2010, less than a year after a devastating earthquake struck Haiti, the country was plagued with a deadly cholera epidemic. Within days of the first case, a National Cholera Surveillance System was set up to direct the country’s public health response. The report from the first two years of the cholera epidemic is featured in this week’s NEJM. I spoke with the study’s lead author, Ezra Barzilay, to understand the scope and context of the cholera epidemic.
SJ: I understand that you have had previous experience with dealing with enteric disease epidemics?
EB: I trained as a pediatrician and then joined the CDC’s Epidemic Intelligence Service in 2004. I led the US National Surveillance Team for Enteric Diseases in the National Center for Emerging and Zoonotic Infectious Diseases at the CDC before becoming the Deputy Incident Manager for the Haiti Cholera Response in 2010.
SJ: Which diseases did you face prior to cholera, and where did they occur?
EB: I had worked internationally in multiple countries. Since I’m a Francophone and also speak Russian, I worked in Francophone Africa and many of the Russian-speaking countries of central Asia. Armenia has the highest rate of botulism in the world, so we had a project there. In Georgia, we dealt with Helicobacter pylori, and in Kazakhstan we dealt with Salmonella surveillance.
SJ: Do you think your experience had prepared you for enteric disease when it struck Haiti?
EB: In Russia, Armenia, and Georgia, all of our projects were centered on lab-based surveillance for the various pathogens. We felt we could apply the same principles to Vibrio [cholerae].
SJ: Okay, so when the outbreak first began in Haiti, who did they first reach out to?
EB: The Haitian government [reached out] to the US through our embassy; our office at the CDC [was one of the ones called].
SJ: What part of the country was affected first?
EB: It became clear to us that the first cases were among communities along the Artibonite River. This river crosses the entire country to the Dominican Republic (see map). But people in Haiti move around quite a bit. Soon, people with cholera were seen in bigger cities.
SJ: Can you say the river led to the spread of the infection?
NS (Nicolas Schaad, also author): We can say there was an association with communities along the river. We can’t say the river was a cause.
SJ: How did people with these first cases of cholera present?
EB: Cholera starts very acutely with diarrhea. In the very first hours, its difficult to distinguish it from other diarrheal diseases. But after the first hour, cholera’s severity really takes off. Cholera is voluminous, aggressive, and severe, with liters of water lost per day. Patients dehydrate very rapidly. What’s almost pathognomic is the quality of stool having no more fecal matter. We call this rice-water diarrhea, which is cloudy water with no particulate matter other than mucus sloughed from the intestine, resembling the water seen when you soak rice and you see the cloudy supernatant. Fever is variable, abdominal pain is expected.
SJ: Was a patient zero ever identified? (Patient zero refers to an index case in an epidemic).
NS: Not that I know of.
SJ: What leads to cholera transmission?
EB: Personal hygiene and water sanitation are the most important factors. Since cholera is spread by the fecal-oral route, food and water can spread the disease. A lot of our prevention efforts were directed at controlling water sources, encouraging use of soap and water with handwashing, use of latrines, avoiding defecation near water sources, and cooking food well.
SJ: Were there specific reasons Haiti was susceptible to a cholera epidemic?
EB: Yes. The earthquake had affected water sanitation systems. That’s important. And secondly, Haiti had never really seen cholera before. It’s probably been two centuries since cholera was seen in Haiti. So the population had no ability to respond to cholera.
SJ: So if water is the main way cholera spreads, can’t people just boil water?
EB: People are obtaining clean water from many different sources. Boiling water is effective, in general, however, they have to expend energy and fuel to do this. What the CDC advocates is a cheap, safe water system, which is essentially a chlorine byproduct used to treat water at the point of use.
SJ: What was the recommended treatment in patients who had developed cholera?
EB: Aggressive rehydration. Antibiotics can be used in severe cases. What was most effective is by January 2011 the CDC was able to scale up cholera treatment by educating community health workers and medical staff, such that they were treating nothing but cholera. We had established dedicated cholera treatment facilities.
SJ: Had an infectious disease outbreak like this ever occurred in Haiti before?
EB: Not to this scale. This is probably the largest. This was an immunologically naïve population with a case fatality rate that was very impressive initially. Within three months, our surveillance program had dropped the case fatality rate to below 1%. This is the gold standard that suggests that control of a cholera outbreak has been achieved.
SJ: Why were you so successful in achieving control?
EB: Because we had such a coordinated response. The CDC, the local NGOs, PAHO (Pan American Health Organization) worked together with a remarkable amount of coordination – our response was overwhelmingly positive.
SJ: Could a cholera outbreak occur in the US?
EB: We have a few isolated cases, usually from consumption of crustaceans and other seafood. However, our robust water sanitation system and surveillance would prevent such an outbreak from occurring.
You can read more about the cholera epidemic in Haiti between 2010-2012 and the surveillance system used to combat its spread in this week’s NEJM: