New sights on PPR pathogenesis and development of PPR live attenuated DIVA vaccines using reverse genetics approach

14 December 2021

The next webinar in our series will take place on Tuesday 14 December 2021 at 12.00 noon GMT (UK time).

Across Africa, Middle East and Asia, Peste des petits ruminants virus (PPRV), places a huge disease burden on agriculture, in particular affecting small ruminant production. The recent outbreaks in Northern Africa, European part of Turkey and Bulgaria represent a significant threat to mainland of Europe, as a source of disease spread.

The current understanding of PPRV pathogenesis has been mainly derived from the closely related rinderpest virus (RPV). There are few studies that have focused on the late stages of pathogenesis of PPRV in the field and very little is known about the processes underlying the early events of pathogenesis. It is believed that PPRV replicates mainly in the respiratory epithelium before disseminating throughout the host. The application of reverse genetics techniques provides a tool to gain a better understanding of the molecular factors underlying virus host range and pathogenesis. Using reverse genetics approach and tagging the virulent PPRV with GFP, it was possible to demonstrate that the virus primarily replicates in dendritic cells inside the pharyngeal tonsil and later on virus replicates in the epithelial cells of respiratory and gastrointestinal tracts.

Although two safe and efficacious live attenuated vaccines are available for PPR control, current serological tests do not enable to differentiate between naturally infected and vaccinated animals (DIVA). This is posing a serious problem for the sero-surveillance programs during ongoing eradication. Further, during the latter stages of any eradication programme ongoing vaccination is only possible if the vaccine used is fully DIVA compliant. Using reverse genetics technique, the existing live attenuated PPR vaccine viruses have been modified to two DIVA vaccines. As a proof of principle, the developed DIVA vaccines have been evaluated in goats in pilot studies and the animals were fully protected similar to the parent vaccines upon virulent PPR virus challenge. It was also possible to differentiate infected from vaccinated animals by two new ELISAs using two recombinant proteins.

The webinar will be given by Professor Satya Parida, Laboratory and Vaccine Specialist at the Food and Agriculture Organisation of the United Nations, and Visiting Professor at the Royal Veterinary College, University of London. Professor Parida's talk will be followed by an opportunity to ask questions. The session will be hosted on an online platform and chaired by IVVN Network Management Board member Professor Brian Perry.

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Professor Satya Parida

Professor Satya Parida, DVM, PhD, is currently engaged as the Laboratory and Vaccine Specialist at Food and Agriculture Organization (FAO) for United Nations (UN). He is trained as a veterinarian and served as the former Head of Vaccine Differentiation Group at the Pirbright Institute, UK. Satya has been working on PPR and FMD vaccines since early 2000 and has published more than 160 research papers in various international scientific journals.

In 2007, he was appointed as an adjunct Professor at the Murdoch University Australia and following this was appointed as a Jenner investigator at the Jenner Institute Oxford University in 2009. His titles also include; visiting faculty at National Institute of Animal Biotechnology (NIAB), India from 2013-2018 and a visiting professor to Royal Veterinary College, London University (2018-2023). Recently he has joined as an honorary member of SACIDS organisation Tanzania (Southern African Centre for Infectious Disease Surveillance). His previous achievements also include; coordinating many international EU, BBSRC, DBT-BBSRC and CIDLID projects between EU, Africa, India and China on FMD and PPR vaccines and Satya has also worked as a BBSRC grant panel member for several years. Currently, he is working as an academic editor for Viruses and PLOS One Journals and is an Editorial Board Member for TBED (Trans Boundary Emerging Diseases), providing expert consultations on vaccines and diagnostics on PPR and FMD to government agencies, contract research organizations and the pharmaceutical industries.

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