title: Toxigenic Vibrio cholerae O1 in vegetables and fish raised in wastewater irrigated fields and stabilization ponds during a non-cholera outbreak period in Morogoro, Tanzania: an environmental health study.
abstract: BACKGROUND
  Cholera, one of the world's deadliest infectious diseases, remains rampant and frequent in Tanzania and thus hinders existing control measures. The present study was undertaken to evaluate the occurrence of toxigenic Vibrio cholerae O1 in wastewater, fish and vegetables during a non-outbreak period in Morogoro, Tanzania.
  
  
  METHODS
  From October 2014 to February 2015, 60 wastewater samples, 60 fish samples from sewage stabilization ponds and 60 wastewater irrigated vegetable samples were collected. Samples were cultured for identification of V. cholerae using conventional bacteriological methods. Isolates were confirmed as V. cholerae by detection of the outer membrane protein gene (ompW) using polymerase chain reaction (PCR). Isolates were further tested for antibiotic susceptibility and presence of virulence genes including, cholera enterotoxin gene (ctx), the toxin co-regulated pilus gene (tcpA) and the haemolysin gene (hlyA).
  
  
  RESULTS
  The prevalence of V. cholerae in wastewater, vegetables and fish was 36.7, 21.7 and 23.3 %, respectively. Two isolates from fish gills were V. cholerae O1 and tested positive for ctx and tcpA. One of these contained in addition the hlyA gene while five isolates from fish intestines tested positive for tcpA. All V. cholerae isolates were resistant to ampicillin, amoxicillin and some to tetracycline, but sensitive to gentamicin, chloramphenicol, and ciprofloxacin.
  
  
  CONCLUSIONS
  Our results show that toxigenic and drug-resistant V. cholerae O1 species are present and persist in aquatic environments during a non-cholera outbreak period. This is of public health importance and shows that such environments may be important as reservoirs and in the transmission of V. cholerae O1.
authors.affiliation: Department of Veterinary Medicine and Public Health, Sokoine University of Agriculture, Morogoro, Tanzania. gilmahu@yahoo.fr.|Research Laboratory in Applied Biology, Polytechnic School of Abomey-Calavi, University of Abomey-Calavi, Abomey-Calavi, Benin. gilmahu@yahoo.fr.
authors.forename: Yaovi M G
authors.initials: YM
authors.lastname: Hounmanou
authors.affiliation: Department of Veterinary Medicine and Public Health, Sokoine University of Agriculture, Morogoro, Tanzania.
authors.forename: Robinson H
authors.initials: RH
authors.lastname: Mdegela
authors.affiliation: Research Laboratory in Applied Biology, Polytechnic School of Abomey-Calavi, University of Abomey-Calavi, Abomey-Calavi, Benin.
authors.forename: Tamègnon V
authors.initials: TV
authors.lastname: Dougnon
authors.affiliation: Department of Veterinary Medicine and Public Health, Sokoine University of Agriculture, Morogoro, Tanzania.
authors.forename: Ofred J
authors.initials: OJ
authors.lastname: Mhongole
authors.affiliation: National Health Laboratory Quality Assurance and Training Centre (NHLQATC), Dar Es Salaam, Tanzania.
authors.forename: Edward S
authors.initials: ES
authors.lastname: Mayila
authors.affiliation: Department of Veterinary Medicine and Public Health, Sokoine University of Agriculture, Morogoro, Tanzania.
authors.forename: Joseph
authors.initials: J
authors.lastname: Malakalinga
authors.affiliation: Department of Veterinary Medicine and Public Health, Sokoine University of Agriculture, Morogoro, Tanzania.
authors.forename: George
authors.initials: G
authors.lastname: Makingi
authors.affiliation: Faculty of Health and Medical Sciences (UC-HEALTH), University of Copenhagen, Copenhagen, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Dalsgaard
mesh_terms: D057914:Agricultural Irrigation; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D003430:Cross-Sectional Studies; D004782:Environmental Health; D005399:Fishes / Q000382:microbiology*; D005798:Genes, Bacterial; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D061005:Ponds; D013636:Tanzania; D014675:Vegetables / Q000382:microbiology*; D041241:Vibrio cholerae O1 / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity; D062065:Wastewater; D014871:Water Microbiology
chemical_list: D000900:Anti-Bacterial Agents; D062065:Wastewater
keywords: Antibiotic susceptibility; Fish; Vegetables; Vibrio cholerae O1; Wastewater