Development of diagnostic systems, reference collections and molecular epidemiology studies for important arboviral pathogens of livestock in India

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This project "Development of diagnostic systems, reference collections and molecular epidemiology studies for important arboviral pathogens of livestock in India" will build on established links between colleagues at The Pirbright Institute, the University of Glasgow, The John Innes Institute and the Royal Veterinary College (in the UK) with The University of Veterinary and Animal Sciences at Hisar in India, creating links with colleagues working with arboviruses in southern India. Outbreaks of arboviral diseases are a significant burden on livestock / farming communites in India. Serological data show that 21 of the 26 bluetongue virus (BTV) seroptypes exist in India, one of the highest levels of BTV diversity anywhere in the world. The severity of BT outbreaks in Indian sheep has increased significantly in recent decades, reaching 30% in some areas, possibly due to introduction of exotic strains. However, very few Indian BTV isolates have been genetically or phenotypically characterised, creating a major barrier to local validation of diagnostics and to control strategies, including development of vaccines. During the past 25 years, multiple strains of BTV and other arboviruses have emerged in Europe, possibly linked to changes in climate and global trade. However, a lack of data concerning global strain-diversity and distribution limits our ability to understand, respond to and control these events. The incomplete nature of the global database for BTV limits our ability to Identify the geographic origin of BT outbreak-strains. Similar problems exist for many endemic arboviruses in India (Myers et al 1971; Padbidri et al 2002). We will address these knowledge-gaps by isolating, identifying and characterising arboviruses from India, to study their distribution, abundance, relationships, and movements that result in disease outbreaks. The primary focus of the project is BTV, although diagnostic samples used to detect and isolate viruses, will also provide materials and potentially isolates of other arboviruses from the region. The reference collection at Pirbright provides different orbiviruses and sequence data, for development and evaluation of diagnostic assays (by RT-PCR). These assays, which identified the BTV types that invaded Europe since 1998, have become widely accepted 'front-line' tools for diagnosis, surveillance and typing of BTV around the world. However they have not yet been widely validated or deployed in India. BTV Isolates from the Pirbright collection were also used to develop / evaluate inactivated vaccine strains that successfully eradicated BTV type 8 from the UK and northern Europe . Well characterised and documented virus isolates will be generated in India, as a basis for a reference collection of 'Indian arboviruses', focussing particularly on BTV and the other orbiviruses. This will provide materials for local development of relevant vaccines (seed stocks and challenge strains) and validation / further-development of diagnostic assays for identification, detection and surveillance of these viruses on the Indian subbcontinent. Linking 'Indian-reference-collections', to the existing collection at Pirbright, will add to the global resources and our knowledge concerning these viruses. Diagnosis, isolations, sequencing, phylogenetics and virus storage will be undertaken in India, with assistance from Pirbright. Phylogenetic and evolutionary analyses will be performed at Pirbright and Glasgow. Pathology studies will be carried out at Pirbright, at the RVC and in India. The project will take advantage of recent developments in plant-based expression technologies at John Innes (JIC) (P3), to generate low-cost reagents for BTV serotyping. This will create links between plant and animal science in the UK and in India. Development of next generation serological assays will take place at JIC and Pirbright, for evaluation at Pirbright and in India.