Widening the scope of PPR diagnostic: Adaptation and development to target atypical host species and field situations

Kwiatek Olivier, Bataille Arnaud, Donnet Fabien, Martin Kevin, Belfkhi Salima, Mounier Lucile, Laffont Mathieu, Comtet Loïc, Libeau Geneviève. 2018. Widening the scope of PPR diagnostic: Adaptation and development to target atypical host species and field situations. In : Book of abstracts of the ESVV 2018. ESVV. Vienne : ESVV, Résumé, 18. International Congress for Veterinary (ESVV 2018). 11, Vienne, Autriche, 27 Août 2018/30 Août 2018.

Matériel d'accompagnement : 1 diaporama (23 vues)

Note générale : A l'occasion de ce congrès, s'est également déroulé le 12. Annual Meeting of EPIZONE.

Résumé : Background Peste-des-petits ruminants (PPR) is a highly contagious and devastat-ing viral disease affecting sheep, goats, and a large number of spe-cies within the order Artiodactyla. Robust commercial serological and virological diagnostic kits are available to detect PPR infection, but they were mainly developed for domestic small ruminants (goat and sheep) and for high quality, invasive samples sometimes hard to obtain in the field. New tools are needed to detect PPR infection in atypical hosts (e.g. camels, wildlife) and in complex field situations. Here we present adaptation of existing methods and new diagnostic tools to resolve some of these issues. In some regions, farmers are reluctant to have their animals handled and tested for PPR infection. As well, in the case of wildlife survey, animal capture is very costly and demands complicated logistics. Detection of PPR virus in non- invasive samples (feces) can be extremely useful in such cases. Methods and results We adapted methods of RNA extraction, RT-PCR, RT-QPCR and anti-gen capture ELISA to detect PPR viral particles or genetic material from fecal samples. The methods were validated with samples col-lected during an infection experiment. Our protocol was then used with fecal samples obtained in the field in Tanzania in 2015, and compared to results obtained from ocular swab samples taken from the same animals. Another issue is that existing LFD tests used in the field do not allow for direct confirmation by PCR. Here we present a new rapid penside test, produced and distributed by IDvet (France), which can be performed without any lab equipment. Lastly, we also tackled the issue of PPR antibody detection from camelid sera, usually suboptimal because of their particular antibody structure. Results Our results show that virus particles can be detected in fecal sam-ples from 4 days post infection (dpi) until at least 14 dpi. Sensitivity of RT-QPCR from fecal samples was similar to RT-QPCR and lateral flow device (LFD) on ocular swab samples. The penside test was as sensi-tive as the antigen capture ELISA test. Once dried, positive strips can be stored and used later on for confirmation by RT-QPCR or RT-PCR. A simple modification of the protocol of a commercially available competitive ELISA for PPR antibody detection (IDvet) increased the sensitivity of the test on camelid serum. Conclusion These tools will be extremely useful to unravel important questions that still remain about PPR epidemiology, notably the role of atypical host in PPR transmission dynamics.

Auteurs et affiliations

• Kwiatek Olivier, CIRAD-BIOS-UMR ASTRE (FRA)
• Bataille Arnaud, CIRAD-BIOS-UMR ASTRE (FRA)
• Donnet Fabien, IDvet (FRA)
• Martin Kevin, IDvet (FRA)
• Belfkhi Salima, IDvet (FRA)
• Mounier Lucile, IDvet (FRA)
• Laffont Mathieu, IDvet (FRA)
• Comtet Loïc, IDvet (FRA)
• Libeau Geneviève, CIRAD-BIOS-UMR ASTRE (FRA)

Source : Cirad-Agritrop (https://agritrop.cirad.fr/590043/)

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