Influence of hydrologic and anthropogenic factors on the abundance variability of enteropathogens in the Ganges estuary, a cholera endemic region

This study deals with the influence of water physico-chemical properties, tides, rainfall and fecal pollution on the abundance of enteropathogens in a main distributary of the Ganges, in the endemic cholera belt of West Bengal. Between January and June 2011, water and sediments were sampled from two sites of the Hooghly River by Kolkata and Diamond Harbour. Counts of cultivable Vibrio (CVC, from ~ 102 to ~ 105 CFU/L) and total bacteria (TBC, from ~ 105 to ~ 109 CFU/L) increased with water temperature (17 °C to 37 °C). A combination of variations in tidal height, salinity and turbidity had a distinct influence on CVC, TBC and coliform counts. At Diamond Harbour, a salinity increase from 0.6 to 7.9 was accompanied by a 1000-fold amplification of initial CVC ~ 102 CFU/L, whereas higher prevalence of coliforms in Kolkata was related to greater disposal of untreated sewage into the river. Turbidity-dependent variation of CVC was noteworthy, particularly at Diamond Harbour, where CVC in intertidal surface sediments showed an analogous trend as in surface waters, suggesting bentho-pelagic coupling of Vibrio dynamics. Besides the influence of salinity variation with tidal cycles, sediment re-suspension from tidal flats can play a role on Vibrio abundance in aquatic ecosystems.Fil: Batabyal, Prasenjit. National Institute For Cholera And Enteric Diseases; IndiaFil: Einsporn, Marc H.. Leibniz Centre For Tropical Marine Ecology; AlemaniaFil: Mookerjee, Subham. National Institute For Cholera And Enteric Diseases; IndiaFil: Palit, Anup. National Institute For Cholera And Enteric Diseases; IndiaFil: Neogi, Sucharit B.. Osaka Prefecture University; Bangladesh. International Centre for Diarrheal Disease Research; BangladeshFil: Nair, Gopinath B.. National Institute For Cholera And Enteric Diseases; India. Translational Health Science and Technology Institute; IndiaFil: Lara, Ruben Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Argentino de Oceanografía (i); Argentin