Validation and feasibility of a novel, simple and rapid assay to detect cholera in resource poor settings and outbreak situations

Epidemiology surveillance - Laboratory surveillance Bangladesh active

Project timeline: 16/09/2019 - 15/02/2022

Lead Researcher

Dr. Subhra Chakraborty

Organisation / Institution

Johns Hopkins University

Funders

Wellcome Trust

Project summary

A rapid diagnostic test (RDT) that is simple, sensitive and specific would be highly valuable for the early confirmation of cholera outbreaks and for hotspot mapping in endemic settings. The current diagnostic tests for cholera, stool culture or RDTs are either requires ~72 hours in a good laboratory or the sensitivity and specificity are not optimal and varies.

We developed a novel RDT assay “Cholera-rapid LAMP based RDT (C-RLDT)” which is simple, rapid (<1hour), directly from stool, sensitive, specific, cold chain free, easy to interpret and inexpensive. This assay targets V. cholerae (ctxA and O1 rfb gene) using isothermal amplification. The limit of detection is similar to quantitative PCR. Our preliminary data with stool samples from endemic countries showed C-RLDT has high sensitivity and specificity compared to PCR and culture method. C-RLDT is capable of detecting cholera in water samples without enrichment.

We propose validating C-RLDT in comparison with culture, Crystal VC® and PCR and determining the operational performance and feasibility of implementing C-RLDT in District clinics as well as in a field setting when outbreaks occur in remote areas in Uganda, Nigeria and Bangladesh. We also propose to determine the validity of C-RLDT in detecting V. cholera from water.

Lay summary

We developed a simple and rapid diagnostic assay “C-RLDT” for the detection of cholera which could be applied to resource-poor settings. This assay is sensitive like PCR and specific and could detect cholera in stool and water. We aim to evaluate the performance and feasibility of the implementation of C-RLDT in Uganda, Nigeria and Bangladesh.

Potential for public health impact or global health decision-making

If this project is successful, C-RLDT could be integrated in the National cholera control plan in the cholera endemic countries.

Co-Investigators

David Sack, Johns Hopkins University as consultant

Key Collaborators

International Centre for Diarrhoeal Disease Research (icddr,b), Bangladesh
Nigeria Center for Disease Control (NCDC), Nigeria
National Health Laboratory & Diagnostic Services (NHLDS/CPHL), Ministry of Health, Uganda