Epidemiology of Vibrio Cholerae Infections in the Households of Cholera Patients in the Democratic Republic of the Congo: PICHA7 Prospective Cohort Study.

BACKGROUND

The aim of this prospective cohort study is to build evidence on transmission dynamics and risk factors for Vibrio cholerae infections in cholera patient households.

METHODS

Household contacts of cholera patients were observed for 1-month after the index cholera patient was admitted to a health facility for stool, serum, and water collection in urban Bukavu in South Kivu, Democratic Republic of the Congo. A V. cholerae infection was defined as a V. cholerae bacterial culture positive result during the 1-month surveillance period and/or a four-fold rise in a V. cholerae O1 serological antibody from baseline to the 1-month follow-up.

RESULTS

Twenty-seven percent of contacts (134 of 491) of cholera patients had a V. cholerae infection during the surveillance period. Twelve percent (9 of 77) of cholera patient households had a stored water sample with V. cholerae by bacterial culture, and 7% (5 of 70) had a water source sample with V. cholerae. Significant risk factors for symptomatic V. cholerae infections among contacts were stored food left uncovered (Odds Ratio (OR): 2.39, 95% Confidence Interval (CI): 1.13, 5.05) and younger age (children <5 years) (OR: 2.09, 95% CI: 1.12, 3.90), and a drinking water source with >1 colony forming unit E.coli / 100mL (OR: 3.59, 95% CI: 1.46, 8.84) for V. cholerae infections.

CONCLUSIONS

The findings indicate a high risk of cholera among contacts of cholera patients in this urban cholera endemic setting, and the need for targeted water treatment and hygiene interventions to prevent household transmission of V. cholerae.