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Increased isolation frequency of toxigenic Vibrio cholerae O1 from environmental monitoring sites in Haiti.

Alam MT, Weppelmann TA, Longini I, De Rochars VM, Morris JG, Ali A - PLoS ONE (2015)

Bottom Line: In a previous study conducted between April 2012 and March 2013, we reported the isolation of toxigenic V. cholerae O1 from surface waters in the Ouest Department.Both seasonal water temperatures and precipitation were significantly related to the frequency of isolation.Our data suggest that toxigenic V. cholerae O1 are becoming more common in surface waters in Haiti; while the basis for this increase is uncertain, our findings raise concerns that environmental reservoirs are being established.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, Florida, United States of America; Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America.

ABSTRACT
Since the identification of the first cholera case in 2010, the disease has spread in epidemic form throughout the island nation of Haiti; as of 2014, about 700,000 cholera cases have been reported, with over 8,000 deaths. While case numbers have declined, the more fundamental question of whether the causative bacterium, Vibrio cholerae has established an environmental reservoir in the surface waters of Haiti remains to be elucidated. In a previous study conducted between April 2012 and March 2013, we reported the isolation of toxigenic V. cholerae O1 from surface waters in the Ouest Department. After a second year of surveillance (April 2013 to March 2014) using identical methodology, we observed a more than five-fold increase in the number of water samples containing culturable V. cholerae O1 compared to the previous year (1.7% vs 8.6%), with double the number of sites having at least one positive sample (58% vs 20%). Both seasonal water temperatures and precipitation were significantly related to the frequency of isolation. Our data suggest that toxigenic V. cholerae O1 are becoming more common in surface waters in Haiti; while the basis for this increase is uncertain, our findings raise concerns that environmental reservoirs are being established.

No MeSH data available.


Related in: MedlinePlus

The isolation frequency of both toxigenic V. cholerae O1 (red bars) and non-toxigenic V. cholerae Non-O1/O139 (gray bars) appear with respect to time overlaid with average monthly water temperature in degrees Celsius (panel A) and accumulated weekly rainfall in millimeters (panel B).
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pone.0124098.g002: The isolation frequency of both toxigenic V. cholerae O1 (red bars) and non-toxigenic V. cholerae Non-O1/O139 (gray bars) appear with respect to time overlaid with average monthly water temperature in degrees Celsius (panel A) and accumulated weekly rainfall in millimeters (panel B).

Mentions: The isolation frequency of V. cholerae O1 and non-O1/O139 from all 17 collection sites is presented by month along with the average water temperature in Fig 2A. In contrast to the year-round isolation of non-toxigenic V. cholerae non-O1/O139 from the environment, the isolation of V. cholerae O1 only occurred during the early summer and late fall (June to November), corresponding with increases in water temperatures. The average water temperature was highly correlated with the isolation frequency of V. cholerae O1 both during the same month (P = 0.002) and the following month (P < 0.001). For each additional one degree Celsius increase (°C) in the average water temperature, the frequency of isolation was almost twice as high (RR = 1.87; 95% CI: 1.27, 2.76) during the same month and 2.2 times as high (RR = 2.23; 95% CI: 1.46, 3.39) the following month. The isolation frequency of V. cholerae O1 and Non-O1/O139 from all 17 collection sites is presented by week along with accumulated rainfall in Fig 2B. As shown, both toxigenic V. cholerae O1 and V. cholerae non-O1/O139 were isolated more frequently during the rainy season (approximately from mid-April to mid-September), however toxigenic V. cholerae O1 was isolated exclusively after the onset of the rainy season until November when the precipitation decreased. The isolation frequency of V. cholerae O1 from the environment increased significantly four to five weeks after increases in accumulated rainfall (P = 0.001, 0.002) and also showed a smaller, less significant increase during the same week (P = 0.036). For each additional 10 mm of accumulated rainfall, there was a 27% increase in isolation frequency during the same week (RR = 1.27, 95% CI: 1.02, 1.58), a 48% increase four weeks later (RR = 1.48, 95% CI: 1.17, 1.87), and a 34% increase five weeks later (RR = 1.12, 1.60).


Increased isolation frequency of toxigenic Vibrio cholerae O1 from environmental monitoring sites in Haiti.

Alam MT, Weppelmann TA, Longini I, De Rochars VM, Morris JG, Ali A - PLoS ONE (2015)

The isolation frequency of both toxigenic V. cholerae O1 (red bars) and non-toxigenic V. cholerae Non-O1/O139 (gray bars) appear with respect to time overlaid with average monthly water temperature in degrees Celsius (panel A) and accumulated weekly rainfall in millimeters (panel B).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390201&req=5

pone.0124098.g002: The isolation frequency of both toxigenic V. cholerae O1 (red bars) and non-toxigenic V. cholerae Non-O1/O139 (gray bars) appear with respect to time overlaid with average monthly water temperature in degrees Celsius (panel A) and accumulated weekly rainfall in millimeters (panel B).
Mentions: The isolation frequency of V. cholerae O1 and non-O1/O139 from all 17 collection sites is presented by month along with the average water temperature in Fig 2A. In contrast to the year-round isolation of non-toxigenic V. cholerae non-O1/O139 from the environment, the isolation of V. cholerae O1 only occurred during the early summer and late fall (June to November), corresponding with increases in water temperatures. The average water temperature was highly correlated with the isolation frequency of V. cholerae O1 both during the same month (P = 0.002) and the following month (P < 0.001). For each additional one degree Celsius increase (°C) in the average water temperature, the frequency of isolation was almost twice as high (RR = 1.87; 95% CI: 1.27, 2.76) during the same month and 2.2 times as high (RR = 2.23; 95% CI: 1.46, 3.39) the following month. The isolation frequency of V. cholerae O1 and Non-O1/O139 from all 17 collection sites is presented by week along with accumulated rainfall in Fig 2B. As shown, both toxigenic V. cholerae O1 and V. cholerae non-O1/O139 were isolated more frequently during the rainy season (approximately from mid-April to mid-September), however toxigenic V. cholerae O1 was isolated exclusively after the onset of the rainy season until November when the precipitation decreased. The isolation frequency of V. cholerae O1 from the environment increased significantly four to five weeks after increases in accumulated rainfall (P = 0.001, 0.002) and also showed a smaller, less significant increase during the same week (P = 0.036). For each additional 10 mm of accumulated rainfall, there was a 27% increase in isolation frequency during the same week (RR = 1.27, 95% CI: 1.02, 1.58), a 48% increase four weeks later (RR = 1.48, 95% CI: 1.17, 1.87), and a 34% increase five weeks later (RR = 1.12, 1.60).

Bottom Line: In a previous study conducted between April 2012 and March 2013, we reported the isolation of toxigenic V. cholerae O1 from surface waters in the Ouest Department.Both seasonal water temperatures and precipitation were significantly related to the frequency of isolation.Our data suggest that toxigenic V. cholerae O1 are becoming more common in surface waters in Haiti; while the basis for this increase is uncertain, our findings raise concerns that environmental reservoirs are being established.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, Florida, United States of America; Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America.

ABSTRACT
Since the identification of the first cholera case in 2010, the disease has spread in epidemic form throughout the island nation of Haiti; as of 2014, about 700,000 cholera cases have been reported, with over 8,000 deaths. While case numbers have declined, the more fundamental question of whether the causative bacterium, Vibrio cholerae has established an environmental reservoir in the surface waters of Haiti remains to be elucidated. In a previous study conducted between April 2012 and March 2013, we reported the isolation of toxigenic V. cholerae O1 from surface waters in the Ouest Department. After a second year of surveillance (April 2013 to March 2014) using identical methodology, we observed a more than five-fold increase in the number of water samples containing culturable V. cholerae O1 compared to the previous year (1.7% vs 8.6%), with double the number of sites having at least one positive sample (58% vs 20%). Both seasonal water temperatures and precipitation were significantly related to the frequency of isolation. Our data suggest that toxigenic V. cholerae O1 are becoming more common in surface waters in Haiti; while the basis for this increase is uncertain, our findings raise concerns that environmental reservoirs are being established.

No MeSH data available.


Related in: MedlinePlus