Overview
This project seeks to validate a molecular screening test for enteric fevers (such as typhoid) for use in eradication programs.
Context and scientific objectives
Enteric fever is a severe disease caused mainly by Salmonella Typhi and Salmonella Paratyphi A. The disease is still very prevalent in Asia and Africa where nearly 21 million cases and more than 220,000 deaths are reported each year.
Data on the incidence of typhoid is rare and unreliable given the lack of specificity and sensitivity of standard diagnostic tests (blood culture and Widal-Felix serodiagnostic test).
With support from the Bill & Melinda Gates Foundation, the Emerging Pathogens Laboratory has been working since 2014 to develop and validate a new method to detect and identify the pathogens responsible for enteric fevers using blood samples.
Methodology
The molecular test is evaluated on 1,200 blood samples from adults and children suspected of typhoid infection. The blood samples are tested using the new method: a pre-culture is used to increase the infectious agent load, followed by nucleic acid extraction and finally molecular detection of the pathogens.
After a validation of the method in Bangladesh, the test is now being validated in Africa (Burkina Faso, Democratic Republic of the Congo, Ghana and Malawi) where the context is different.
Results
Promising preliminary results from the study in Africa have allowed the integration of this test as a surveillance tool in a clinical study (THECA) for the introduction of a WHO prequalified vaccine against typhoid fever in Ghana and the Democratic Republic of the Congo.
Partners
Funder:
Scientific:
- International Vaccine Institute
- University of Cambridge (United Kingdom)
- Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University for Science and Technology, Kumasi, Ghana
- Kwame Nkrumah University of Science and Technology (KNUST), Kumasi (Ghana)
- Ouagadougou Higher Institute of Population Science (ISSP), Ouagadougou, Burkina Faso
- Malawi-Liverpool-Wellcome Trust, Clinical Research Programme
- Emerging Pathogens Laboratory, Lyon, France
- National Institute of Biomedical Research (Democratic Republic of the Congo)