Since October 2010 more than 700,000 cases of cholera have been reported in Haiti with more than 8,000 deaths. Detection of the waterborne bacterium that causes cholera, toxigenic Vibrio cholerae, is key to predicting when and where cholera outbreaks will occur, but previous attempts to detect this microorganism in Haitian water sources have had limited success.
Now, University of Florida researchers led by Dr. Afsar Ali, a research associate professor in the UF College of Public Health and Health Professions’ department of environmental and global health and a member of the Emerging Pathogens Institute, report that they have detected Vibrio cholerae in several water samples taken at sites in the Gressier and Leogane areas of Haiti. Their findings suggest that cholera may now have established environmental reservoirs in Haiti, a key element in establishment of endemicity.
The UF team’s success comes from modification of testing techniques to allow for easy detection of the bacterium. The team’s findings appeared in the journal Emerging Infectious Disease.
“While Vibrio cholerae is a natural component of aquatic reservoirs, it maintains a seasonal pattern, with increased temperature and rainfall promoting blooms of V. cholerae that can subsequently spillover to humans, causing cholera,” said Dr. Ali. “Timely detection of toxigenic V. cholerae in aquatic environments is important because it can alert health officials to mobilize and implement cholera intervention strategies to stem a full-blown cholera epidemic.”
For reasons yet to be determined, isolating toxigenic V. cholerae from water sources has remained very challenging, Dr. Ali said.
“Generally tens of milliliters to tens of liters of water are processed to detect V. cholerae with a minimal success rate,” he said, adding that in previous large-scale studies performed in many cholera endemic countries, about five percent or less of water samples were found positive for V. cholerae, even during ongoing cholera outbreaks.