The role of in-house transmission on the incidence of Vibrio cholerae, the deadly waterborne pathogen, is still not developed. The aim of the current study was to investigate possible contamination routes in household domain for effective cholera control in Bangladesh. To examine the prevalence of V. cholerae, routine swabs from four hotspots (cutting knife, latrine door knob, drinking water pot and food plate surface) and leftover food samples were collected. The cohort of 22 low income households has been studied for every 6 weeks between November 2014 and December 2015, from an urban area of northwest Dhaka, Bangladesh. Molecular genotypic and phenotypic traits of V. cholerae strains were assessed. Total 660 hotspot samples were analyzed by V. cholerae species-specific ompW gene PCR. Among them most predominant was food plate swabs with 37 samples positive out of 163 (22.69%), followed by water pot (17 of 163, 10.43%), knife (6 of 167, 3.6%), latrine door knob (5 of 167, 2.9%). In total 137 food samples were analyzed, only 10 found positive in PCR. Further characterization of ompW positive hotspot total DNA for virulence genotype revealed the presence of rfb O1, rfb O139, tcp, cep genes but lacked the major cholera toxin genes ctxA and ctxB. Only one food tDNA sample was positive for rfb O1 gene. Of the 12 hotspot and 2 food V. cholerae strains isolated from PCR positive samples, 8 (66.6%) were harvested during time period of May-June. One hotspot strain was confirmed as V. cholerae O1 and others as non-O1/ O139 through PCR based analysis. The O1 strain lacked cholera toxin genes but possessed other regulatory and virulent genes like toxR, rtxC, hly, msh, HA/protease. Genes for type three secretion systems were detected in two non-O1/O139 isolates. All the strains including clinical V. cholerae El Tor strain N16961, showed hemolysis and proteolysis activity but none of them exhibited any hemagglutinin activity on human erythrocytes. The study findings indicate that V. cholerae contamination is mostly originated in and around kitchen area rather than latrine area. Contaminated food and water supply may be the reason behind this relatively high presence of virulence factors in food plates and water pots. Direct exposure routes of disease transmission should be a major consideration in cholera prevention policies.

Investigation of household contamination of Vibrio cholerae in Bangladesh.. Available from: https://www.researchgate.net/publication/305215719_Investigation_of_household_contamination_of_Vibrio_cholerae_in_Bangladesh [accessed Oct 14, 2016].