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

Abstract

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. Household contacts of cholera patients were observed for 1 month after the index cholera patient was admitted to a healthcare 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 4-fold rise in a V. cholerae O1 serological antibody from baseline to the 1-month follow-up. Sixty-seven percent of cholera patient households (56/83) had ≥1 V. cholerae infected contact during the 1-month surveillance period. Twenty-seven percent of contacts (134 of 491) of cholera patients had a V. cholerae infection. 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) for water sources. 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 Escherichia coli 100 mL (OR: 3.59, 95% CI: 1.46, 8.84) for V. cholerae infections. None of the contacts residing in households where the index patient consumed doxycycline in the past 48 hours had a V. cholerae infection compared with 28% of contacts (133 out of 470) where the index patient did not consume doxycycline (P = .005). 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.