Cholera: A Detective Story
When cholera hit earthquake-ravaged Haiti, MGH physicians moved in to investigate and traced the strain of bacteria to its source.
In October 2010, almost 10 months after an earthquake had devastated the Caribbean nation of Haiti, a four-year-old boy was admitted to a hospital in Petite Rivière de l’Artibonite after 10 hours of diarrhea and vomiting. Normally, a simple lab test using a stool sample would classify the type of diarrheal illness. But because there was no lab, Jason Harris, a pediatrician at MGH who was part of a team working in Haiti, relied on “clinical suspicion” to diagnose the child’s condition: The boy was almost certainly infected with the bacterium Vibrio cholerae.
An intestinal infection that sickens as many as 5 million people worldwide each year and kills 100,000 to 120,000, cholera is a primary concern of infectious disease specialists such as Harris, who is a co-investigator for the NIH International Collaborations in Infectious Disease Research program, led by Stephen Calderwood, chief of infectious disease at MGH, and Firdausi Qadri at the International Centre for Diarrhoeal Disease Research in Bangladesh. One goal of Harris and the other visiting MGH physicians was to identify the strain of cholera that was sickening Haitians. Understanding the origin and composition of the strain could aid in selecting appropriate antibiotic therapy and gauge its potential impact on a population that hadn’t seen cholera in decades.
When a specimen from another Haitian child showing the same symptoms as those in the four-year-old was analyzed in an MGH lab, it confirmed the V. cholerae diagnosis. Further tests, completed in Menlo Park, Calif., using an advanced DNA sequencing method, revealed that the strain was an especially virulent type of El Tor O1, associated with recent cholera outbreaks in South Asia. Epidemiologists speculated that the strain may have been carried to Haiti by Asian peacekeepers in the country for earthquake relief efforts.
After receiving rehydration solutions and antibiotics, the four-year-old boy was discharged on the third morning. Yet despite efforts by this and other teams of doctors, by August 2011 about 439,000 people had been sickened in the Haiti epidemic and 6,200 had died.