Conference abstract

A cholera outbreak caused by drinking contaminated river water, Bulambuli district, Eastern Uganda, April 2016

Pan African Medical Journal - Conference Proceedings. 2017:6(23).21 Dec 2017.
doi: 10.11604/pamj-cp.2017.6.23.505

Contact the corresponding author
Keywords: Cholera, rivers, disease outbreaks, Uganda

A cholera outbreak caused by drinking contaminated river water, Bulambuli district, Eastern Uganda, April 2016

Paul Edward Okello1,&, Lilian Bulage1, Daniel Kadobera1, Alex Riolexus Ario1, Bao-Ping Zhu2

1Uganda Public Health Fellowship Program, Kampala, Uganda, 2US Centers for Disease Control and Prevention, Uganda

&Corresponding author
Paul Edward Okello, Uganda Public Health Fellowship Program, Kampala, Uganda


Introduction: Bulambuli district, Eastern Uganda experienced a cholera outbreak since January, 2016. Generic control measures implemented by the local public health authorities failed to contain the outbreak. In late March, a sharp increase in the number of cases occurred in Bwikhonge Sub-county. We conducted an investigation to determine the scope of the outbreak, mode of transmission, and to inform control interventions.

Methods: we defined a suspected case as a sudden onset of watery diarrhea from 1 March 2016 onwards in a resident of Bulambuli District. A confirmed case was a suspected case with positive stool culture for V. Cholerae. We conducted active case-finding, performed descriptive epidemiologic analysis, and interviewed 40 suspected case-patients for hypothesis generation. We conducted a case-control study in which we interviewed 100 case-patients and 100 asymptomatic controls, matched by village of residence and age. We also conducted an environmental assessment.

Results: we identified 108 suspected cases (attack rate: 1.3%, 108/8404), 8 of which were confirmed cases. Low level transmission occurred between 2 and 21 March. Cases sharply increased on 24 March, followed by a six-day plateau and a rapid decline after 30th March, indicating a continuous common-source outbreak. The case-control study showed that 76% (76/100) of case-patients versus 54% (54/100) of control-persons usually collected drinking water from the nearby Cheptui River (ORMH= 7.8, 95% CI = 2.7 - 23); conversely, 36% (35/98) of case-patients and 54% (54/100) of control-persons usually collected drinking water from boreholes (ORMH= 0.30, 95% CI = 0.13 - 0.65). A case-patient with onset on 22 March defecated near the water collection point in the river; subsequently, many case-patients washed their soiled clothes at the drinking-water collection point. Vibrio cholera 01 Ogawa was isolated in 2 of the 7 river water samples.

Conclusion: this cholera outbreak was caused by drinking water from Cheptui River contaminated by a patientís feces initially and washing of soiled clothes subsequently. We recommended health education on boiling and/or treating water, restriction on washing clothes near river water collection points, improved sanitation, and distributing chlorine tablets to the affected villages, and, as a long term solution, construction of more boreholes. After implementing our recommendations, cases declined and completely stopped after 6 April.