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

Morgane Gourlaouen,Angélique Angot,Cristian De Battisti,Baba Soumaré,Barbara Zecchin,Stefania Leopardi,Marzia Mancin,Charles Bebay,Calogero Terregino,Paola De Benedictis,Francesca Ellero,Amy T Gilbert

doi:10.1371/journal.pntd.0008010

Abstract

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.

Highlights

Rabies virus still claims more than 59,000 human lives every year and affects lower socio-economic groups in resource-poor countries
This study presents the results obtained by applying the Direct Fluorescent Antibody (DFA) test and the conventional RT-PCR method to the proficiency test (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
Fourteen laboratories operating within the framework of either the Ministry of Agriculture or the Ministry of Health in thirteen African countries were invited to participate in the PT exercise and they all accepted

Summary

Introduction

Rabies virus still claims more than 59,000 human lives every year and affects lower socio-economic groups in resource-poor countries. Tools are available to support and guide countries in developing national programs and strategies for sustainable rabies prevention, rabies control and gradually progress towards rabies elimination [4]. In this context, estimating the disease burden relies on accurate surveillance plans in the field. An accurate diagnosis of animal rabies cases is crucial to monitor the progress of control efforts and to advise in the clinical management of patients that have been potentially exposed to the virus

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