Conference abstract

A cholera outbreak caused by drinking contaminated water from a fenced lakeshore water-collection site – Kasese District, western Uganda, June 2015

Pan African Medical Journal - Conference Proceedings. 2017:1(3).11 Dec 2017.
doi: 10.11604/pamj-cp.2017.1.3.8

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Keywords: Cholera, outbreak, vibrio cholera, Uganda
Oral presentation

A cholera outbreak caused by drinking contaminated water from a fenced lakeshore water-collection site – Kasese District, western Uganda, June 2015

Gerald Pande1,&, Benon Kwesiga1, Godfrey Bwire2, Alex Riolexus Ario1

1Uganda Public Health Fellowship Program, Kampala, Uganda, 2Ministry of Health, Kampala, Uganda

&Corresponding author
Gerald Pande, Uganda Public Health Fellowship Program, Kampala, Uganda

Abstract

Introduction: on 20 June 2015, a cholera outbreak affecting >30 people was reported in a fishing village in Kasese District, western Uganda. We investigated this outbreak to identify the transmission mode and recommend control measures.

Methods: we defined a suspect case as a person with onset of acute watery diarrhea from June 2015 onward; a probable case was a suspected case with positive Rapid Diagnostic Test for cholera; a confirmed case was a suspect case with Vibrio cholerae cultured from stool. We conducted active case-finding in the village. In a case-control study we compared exposure histories of 39 suspected cases and 156 controls matched by age.We also conducted an environmental assessment.

Results: we identified 61 suspect cases (attack rate = 5.1%, 61/1200), including 19 probable cases and 8 confirmed cases. The epidemic curve indicated an initial point-source outbreak followed by secondary transmission: after the primary case’s onset on 16 June, cases rapidly increased and peaked on 19 June, and rapidly declined afterwards; 8 scattered secondary cases occurred after 22 June. 95% (37/39) of cases and 67% (104/156) of controls usually collected water from water-collection Site A (ORM-H = 9.3; 95%CI = 2.1-39). The primary case developed cholera symptoms while fishing, came on ashore the night of 16 June, and defecated near Site A. The village’s tap-water system broke down 8 months ago, forcing villagers to collect water from the lake.

Conclusion: this cholera outbreak was caused by drinking lake water collected at Site A, contaminated by the primary case-person’s faeces. At our recommendations, the local authorities rigorously disinfected all case-persons’ faeces, provided water treatment tablets, issued a water-boiling advisory, and three weeks later fixed the dysfunctional tap-water system. No cases occurred after 1st July.