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

Bryony Anne Jones,Richard Kock,Julius Keyyu,Carrie Batten,Mark Henstock,Mana Mahapatra,Chobi Chubwa,Hayley Hicks,Brian Clarke,Satya Parida

doi:10.3390/v12040389

Abstract

Peste des petits ruminants (PPR) disease was first confirmed in Tanzania in 2008 in sheep and goats in Ngorongoro District, northern Tanzania, and is now endemic in this area. This study aimed to characterise PPR disease in pastoralist small ruminant flocks in Ngorongoro District. During June 2015, 33 PPR-like disease reports were investigated in different parts of the district, using semi-structured interviews, clinical examinations, PPR virus rapid detection test (PPRV-RDT), and laboratory analysis. Ten flocks were confirmed as PPRV infected by PPRV-RDT and/or real-time reverse transcription-polymerase chain reaction (RT-qPCR), and two flocks were co-infected with bluetongue virus (BTV), confirmed by RT-qPCR. Phylogenetic analysis of six partial N gene sequences showed that the PPR viruses clustered with recent lineage III Tanzanian viruses, and grouped with Ugandan, Kenyan and Democratic Republic of Congo isolates. No PPR-like disease was reported in wildlife. There was considerable variation in clinical syndromes between flocks: some showed a full range of PPR signs, while others were predominantly respiratory, diarrhoea, or oro-nasal syndromes, which were associated with different local disease names (olodua—a term for rinderpest, olkipiei—lung disease, oloirobi—fever, enkorotik—diarrhoea). BTV co-infection was associated with severe oro-nasal lesions. This clinical variability makes the field diagnosis of PPR challenging, highlighting the importance of access to pen-side antigen tests and multiplex assays to support improved surveillance and targeting of control activities for PPR eradication.

Highlights

Peste des petits ruminants virus (PPRV, small ruminant morbillivirus) causes a highly contagious disease of domestic sheep and goats and some free-ranging and captive wild artiodactyls
The most important species to be clinically affected by PPR disease are sheep and goats [1], sporadic outbreaks of PPR disease have been reported in camels [9,10]
Samples from three flocks were positive for bluetongue virus (BTV) by RT-qPCR, including two flocks that were infected with peste des petits ruminants virus (PPRV)

Summary

Introduction

Peste des petits ruminants virus (PPRV, small ruminant morbillivirus) causes a highly contagious disease of domestic sheep and goats and some free-ranging and captive wild artiodactyls. Peste des petits ruminants (PPR) is a transboundary disease that is endemic in many parts of Africa and Asia. The most important species to be clinically affected by PPR disease are sheep and goats [1], sporadic outbreaks of PPR disease have been reported in camels [9,10]. In wild artiodactyls in Asia, there have been various reports of confirmed PPR disease under natural conditions [18,19] and in zoological collections [20,21], but rarely in Africa [22,23]. The role that wildlife play in the epidemiology of PPR is unclear, whether they are infected by virus spillover from domestic animals or whether they can act as bridge or maintenance hosts and contribute to PPRV spread and/or maintenance [24]

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