Optimization and evaluation of a non-invasive tool for peste des petits ruminants surveillance and control

Abstract

Peste des petits ruminants (PPR) is a highly contagious and devastating viral disease affecting mainly sheep and goats, but also a large number of wild species within the order Artiodactyla. A better understanding of PPR transmission dynamics in multi-host systems is necessary to efficiently control the disease, in particular where wildlife and livestock co-occur. Notably, the role of wildlife in PPR epidemiology is still not clearly understood. Non-invasive strategies to detect PPR infection without the need for animal handling could greatly facilitate research on PPR epidemiology and management of the disease in atypical hosts and in complex field situations. Here, we describe optimized methods for the direct detection of PPR virus genetic material and antigen in fecal samples. We use these methods to determine the detection window of PPR in fecal samples, and compare the sensitivity of these methods to standard invasive sampling and PPR diagnostic methods using field samples collected at a wildlifelivestock interface in Africa. Our results show that quantitative reverse transcription PCR (RT-QPCR) amplification of PPRV from fecal swabs has good sensitivity in comparison to ocular swabs. Animals infected by PPRV could be identified relatively early on and during the whole course of infection based on fecal samples using RT-QPCR. Partial gene sequences could also be retrieved in some cases, from both fecal and ocular samples, providing important information about virus origin and relatedness to other PPRV strains. Non-invasive strategies for PPRV surveillance could provide important data to fill major gaps in our knowledge of the multi-host PPR epidemiology. Peste des petits ruminants (PPR) is a highly contagious and devastating disease caused by a virus of the genusMorbillivirus in the family Paramyxoviridae 1 . PPR virus (PPRV) affects mainly sheep and goats, but also a large number of wild species within the order Artiodactyla 1,2 . PPR occurrence in livestock must be notified to the World Organization for Animal Health (OIE) and the disease is now the target of a global eradication campaign 3 . PPR is endemic in large parts of Africa, the Middle East and Asia, and is still spreading globally, with emergence notably reported in Georgia 4 , Mongolia 5 , and most recently within the European Union in Bulgaria 6 .Better understanding of PPR transmission dynamics is necessary to efficiently control the disease. Notably, the role of wildlife in PPR epidemiology is still not clearly understood 7,8 . Importantly, the potential for spill-over PPR infection between wildlife and livestock and the direction of these spill-overs are still poorly studied. Also, the capacity of PPR virus to be transmitted and maintained within wildlife populations without a domestic host source has still not yet been demonstrated. The role of wildlife is particularly important to explore in Africa and Central-South Asia including the Himalayas where multi-host systems composed of a large diversity and population of wild ungulate species an...

Camelids and Cattle Are Dead-End Hosts for Peste-des-Petits-Ruminants Virus

“…The host traits of other species susceptible to PPRV-infection according to serological or virological evidence is still under investigation or unknown. We therefore suggest the terms "typical" hosts for domestic small ruminants and "atypical" hosts for other susceptible host species of PPRV, similar to Bataille, et al [29] and Abdullah, et al [30].…”

Characterisation of Peste Des Petits Ruminants Disease in Pastoralist Flocks in Ngorongoro District of Northern Tanzania and Bluetongue Virus Co-Infection

“…Faeces samples were shipped in dry ice to Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), France, where they were stored at −80 • C until analysed. The laboratory analysis of the faecal samples has been reported elsewhere [45].…”

Rapid Detection of Peste des Petits Ruminants Virus (PPRV) Nucleic Acid Using a Novel Low-Cost Reverse Transcription Loop-Mediated Isothermal Amplification (RT-LAMP) Assay for Future Use in Nascent PPR Eradication Programme

“…However, the efficiency of laboratory diagnosis can be greatly influenced by the type and integrity of the sample received [1,29]. The recommended specimens from live animals are nasal, ocular and oral swabs, blood; dead animals: lymphoid tissues and lung tissue; wildlife: non-invasive samples like faecal material [30]. Further, the best sample for conventional RT-PCR is buffy coat [31]; RT-qPCR: nasal swab and blood [22].…”