Vibrio cholerae Epidemiologic and Genomic Surveillance and Transmission, Eastern Democratic Republic of the Congo (PICHA7 Research Program)

Study Objectives

In partnership with the Democratic Republic of the Congo (DRC) Ministry of Health, we plan to conduct 4 years of epidemiological and genomic cholera surveillance at 115 healthcare facilities in South Kivu province of the DRC. This research is part of the Preventative-Intervention-for-Cholera-for-7-Days (PICHA7) research program, a DRC-specific adaptation of the WASHmobile Program.

We have four primary aims:

• To evaluate the effectiveness of a single-dose of Euvichol-Plus, a killed whole-cell oral cholera vaccine (kOCV), during the 24-month period following a preventive kOCV campaign.
• To investigate Vibrio cholerae transmission dynamics among cholera patients, household members, and water sources through longitudinal epidemiological surveillance and whole genome sequencing.
• To characterize the spatiotemporal spread of cholerae in this cholera-hyperendemic region using whole genome sequencing.
• To evaluate the performance of the Crystal VC O1 rapid diagnostic test (RDT) for cholera detection compared to bacterial culture and polymerase chain reaction (PCR) for cholerae.

Study Design

From 2020 to 2024, we will conduct passive surveillance for cholera patients at 115 healthcare facilities in Bukavu, DRC. Stool samples will be collected from diarrhea patients presenting at surveillance healthcare facilities with three or more loose stools within a 24-hour period and analyzed by RDT, bacterial culture, and PCR for V. cholerae. Confirmed cholera patients and their household members will be enrolled and followed for 1 month. Whole genome sequencing of clinical and water-derived V. cholerae strains will be collected to investigate spatiotemporal transmission dynamics of V. cholerae in cholera hotspots.

This project in South Kivu province of the Democratic Republic of the Congo (DRC) will carry out four years of cholera surveillance in 115 healthcare facilities. The goal is to better understand how cholera spreads and how it can be prevented in a region where the disease is common. This research is part of the Preventative-Intervention-for-Cholera-for-7-Days (PICHA7) research program, a DRC-specific version of the WASHmobile Program.

The study will examine how well a single dose of the oral cholera vaccine Euvichol-Plus protects people during the two years following a preventive vaccination campaign. It will also explore how cholera bacteria are transmitted between patients, their household members, and household water sources, using advanced genetic testing (whole genome sequencing). Additionally, researchers will track when and where cholera cases appear to better understand how the disease spreads over time across communities. Finally, the study will test how accurate a rapid cholera diagnostic tool (Crystal VC) is, by comparing it to traditional lab methods like bacterial culture and PCR testing.

By combining laboratory testing, community-based follow-up, and advanced genetic analysis, this study aims to generate critical data to improve cholera detection, prevention, and response efforts in the DRC and other cholera-prone regions.

By evaluating the long-term effectiveness of a single-dose oral cholera vaccine (Euvichol-Plus), this research could inform vaccine policy and cholera vaccine campaign strategies in the DRC and other cholera-endemic countries, particularly where resources for multi-dose cholera vaccine campaigns are limited. The study will offer valuable insights for outbreak response and targeted water, sanitation, and hygiene interventions. Additionally, by validating a rapid diagnostic test against gold-standard methods, the study may support the broader use of faster, more accurate, and more accessible tools for cholera detection—critical for timely public health responses. Together, these findings can shape evidence-based guidelines for cholera control programs at national and international levels.