An inter-laboratory trial as a tool to increase rabies diagnostic capabilities of Sub-Saharan African Veterinary laboratories.

To achieve the goal of eliminating dog-mediated human rabies deaths by 2030, many African countries have agreed to list rabies as a priority zoonotic disease and to undertake both short and long-term control programs. Within this context, reliable local diagnosis is essential for the success of field surveillance systems. However, a harmonized, sustainable and supportive diagnostic offer has yet to be achieved in the continent. We herewith describe the organization and outcome of a proficiency test (PT) for the post-mortem diagnosis of rabies in animals, involving thirteen veterinary laboratories and one public health laboratory in Africa. Participants were invited to assess both the performance of the Direct Fluorescent Antibody (DFA) test and of a conventional RT-PCR. From the submitted results, while thirteen laboratories proved to be able to test the samples through DFA test, eleven performed the RT-PCR method; ten applied both techniques. Of note, the number of laboratories able to apply rabies RT-PCR had increased from four to ten after the exercise. Importantly, results showed a higher proficiency in applying the molecular test compared to the DFA test (concordance, sensitivity and specificity: 98.2%, 96.97% and 100% for RT-PCR; 87.69%, 89.23% and 86.15% for DFA test), indicating the feasibility of molecular methods to diagnose animal pathogens in Africa. Another positive outcome of this approach was that negative and positive controls were made available for further in-house validation of new techniques; in addition, a detailed questionnaire was provided to collect useful and relevant information on the diagnostic procedures and biosafety measures applied at laboratory level. Author summary: Although Africa has the highest per capita death rate from rabies, the incidence of canine rabies on the continent remains a matter that needs to be further investigated; in addition, the lack of accurate information impairs the establishment of long-term actions to progress towards a rabies free status. In this scenario, creating efficient diagnostic facilities is of utmost importance for eradicating the disease and implementing effective surveillance programs in endemic areas. With the final objective of eliminating dog-mediated human rabies globally by 2030, sample submission to African veterinary laboratories for rabies diagnostic testing is expected to increase. Furthermore, in compliance with ISO/IEC 17025:2017 standard, participating to proficiency testing (PT) exercises becomes mandatory not only to regularly assess the validity of the in-house protocols but also to harmonize the techniques. Thirteen veterinary laboratories and one public health laboratory in Africa were invited to take part in the exercise in response to an invitation from the Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe), Italy, which hosts the FAO rabies Reference Center. This study presents the results obtained by applying the DFA test and the conventional RT-PCR method to the PT panel, which show that even if laboratories preferably apply the DFA test to detect the presence of rabies in animal samples, the overall concordance of results was higher through molecular testing. Importantly, the organization of the exercise proved to be a good opportunity to update the vaccine cover status of laboratory staff. [ABSTRACT FROM AUTHOR]