How unbelievable would you say it is to arrive on the verge of the 200^th anniversary of the birth of John Snow and be told that a large outbreak of cholera comparable to the one in Snow’s London has occurred? And what if the origin remained unsolved until a courageous investigator showed up to lead an epidemiologic investigation and establish the source of the outbreak? Would you say impossible because there are too many similarities with Snow’s work? Or would you say impossible because it has been too long ago for history to repeat itself? Sometimes life is stranger than fiction.

Intriguing Observations

Ralph Frerichs, retired UCLA epidemiologist and creator of the most extensive website about John Snow, became intrigued with details of the recent cholera outbreak in Haiti in 2010. He told the Monitor he wondered why the investigation was not producing a more definitive account of the source of the outbreak. Since cholera had been absent from Haiti for a long time, either the organism was an aquatic bacterium that emerged to infect humans because of some environmental change like an earthquake or climate change, or the organism was imported from another country. Why could the source not be pinned down by all the early investigations?

A Medical Detective Opportunity

Early in the outbreak Frerichs wrote on his Snow website “the story of the emergence and impact of cholera in Haiti is similar to what Dr John Snow faced in London in the mid-1880s.” He states that his website posting was to “stimulate further inquiry on origin, namely how the index case or cases came about.”

Frerichs told the Monitor he got “terribly intrigued” by the failure of the early investigators to pinpoint conclusively the source of the outbreak. He felt that something was not quite right with the reports he was reading. According to Frerichs, “I could not believe they could not wrap it up. They were omitting all the basic things and tip-toeing around the findings.”

Given this situation, Frerichs’s idea was that an investigator with Snow’s qualities to help conduct an invigorated investigation could lead to identifying the source and to preventive action. If this happened, there might be a case, he said on his website, to “anoint the skilled investigator and activist as a modern ‘John Snow’.” How surprising would that be?

Snow Website

In impressively detailed and documented narratives on his website and in a scientific paper published in Clinical Microbiology and Infection last year, Frerichs and colleagues have described the evolution of the outbreak in Haiti, the laboratory investigations, and the epidemiologic investigations by teams of Haitian and French epidemiologists.

Initial Reports and Reactions

Initial reports coming from residents and journalists who went to the scene implicated UN peacekeepers who had newly arrived in the country as the source of the outbreak. However, some described these accounts as unsubstantiated rumors. Others pushed the climate change hypothesis as the most likely cause.

Recap Paper

The Clinical Microbiology paper recaps the compelling evidence that 1) peacekeeping soldiers came to Haiti from Nepal where a cholera epidemic had just occurred, 2) quickly after the soldiers arrived, cases of cholera appeared in the community near the soldier’s camp, 3) pipes from the camp leaked fecal waste into the river, 4) waste from the camp was seen being dumped in an unusual location, 5) a waste septic pit near the camp allowed waste fluids to seep into a nearby river, and 6) strains of cholera isolated from Haiti and Nepal were a perfect match in the lab.

The original paper documenting the new findings was published by Piarroux and colleagues in Emerging Infectious Diseases in 2011. However, questions of origin of the epidemic continued to be widely debated. In the Clinical Microbiology paper published a year later in 2012, Frerichs in collaboration with Piarroux and others included all the more recent epidemiological and molecular-genetic evidence.

Conclusion

The authors concluded “ the onset of cholera in Haiti was not the result of climatic factors and was not the direct consequence of the January 2010 earthquake. All of the scientific evidence shows that cholera was brought by a contingent of soldiers traveling from a country experiencing a cholera epidemic. Understanding what triggered the epidemic is important for preventing future occurrences, and acknowledges the right of Haitians to understand the events that led to their cholera devastation.” More than 500,00 cases and more than 7,000 deaths were attributed to the epidemic.

First Do No Harm

In their original report, Piarroux and colleagues had  concluded that their findings were relevant to all aid organizations which should avoid adding “epidemic risk factors to those already existing and respect the fundamental principle of all assistance, which is initially not to harm---primum non nocere.”

Deadly River

Frerichs told the Monitor he is writing a book to recount the full story of this investigation entitled “Deadly River”. According to Frerichs, the investigation of the source of cholera in Haiti was “quite an adventure”. What happens, he asked, if the outcome of your epidemiologic investigation is inconvenient, that is, it implicates a famous person, place, or organization? Various socio-political considerations arise, he claims, and interesting and challenging problems then come up. You need to be able to see it and tell it like it is, according to Frerichs, which is what John Snow had and was able to do. “Renaud Piarroux in this way shares in Snow’s character,” says Frerichs.

A Modern Day Snow?

 Asked if he was prepared to anoint Piarroux as the modern day Snow, Frerichs says he is a worthy candidate for that honor, but he wants to wait until after the book is written to commit himself fully to that decision. “The drama in the book,” he said, “is created by all the day to day cover ups and obfuscations that took place. If all you want to know is who brought cholera to Haiti, then my book is not for you. But if you are interested in the outbreak as an epidemiologist, that is, in how the investigation unfolded and what were the travails encountered because of an inconvenient finding, then ‘Deadly River’ should be interesting to you.”

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