Epidemic Cholera in Urban Lusaka, Zambia, 2017: Groundwater and Contact with Patients as Risks

  • Water or foodborne
Export to CSV
Background: On October 6, 2017, the Zambia Ministry of Health declared a cholera outbreak in Lusaka. By early December, 1,462 cases and 38 deaths had occurred (case fatality rate, 2.6%). We conducted a case-control study to identify risk factors.
Methods: A case was defined as any person with acute watery diarrhea (>3 loose stools in 24 hours) admitted to a cholera treatment center in Lusaka from December 16–21. Controls were neighbors without diarrhea during the same time period. Up to two controls were matched to each case by age group (2-4, 5-17, ≥18 years) and neighborhood. Surveyors interviewed cases and controls using a structured questionnaire, tested free chlorine residual (FCR) in stored water and observed presence of soap in the home. Conditional logistic regression was used to generate matched odds ratios (mOR) based on district and age group with 95% confidence intervals (CI).
Results: We enrolled 82 cases and 132 controls. Common drinking water sources among cases were borehole (35%), shallow wells (26%), and kiosks (13%). Stored water in 72% of case homes had acceptable FCR levels (>0.2 mg/L); 42% of cases reported chlorinating their water within five days of interview. In multivariable analyses, cases had increased odds of drinking borehole water (35% versus 23%, mOR=2.4, 95%CI:1.1–5.6); living in the same house as another case (34% versus 7%, mOR=6.2, 95%CI:2.5–15), and being male (54% versus 30%, mOR=2.5, 95% CI:1.4–5.0).
Conclusions: Use of groundwater for drinking, contact with a cholera case and male sex were associated with cholera. Based on these findings, we recommended health education about household water chlorination, and hygiene in the home. Emergency responses included providing chlorinated water through emergency tanks, and maintaining adequate FCR levels through close monitoring of water sources.

Please abstracts [at] tephinet [dot] org (email us) if you have any corrections.

If this abstract has been converted into a full article, please abstracts [at] tephinet [dot] org (email us) the link. We would love to help promote your work.