Morbillivirus Group - continued

PPRV infection is one of the most important constraints to the increased production of small ruminants in West Africa and severe epizootics have also occurred in the Middle East and across the north of the Indian sub-continent (Figure 3).

The virus is now spreading from Afghanistan into the neighbouring countries of the former Soviet Union and has recently entered China.

Group

In association with the United Nations Food and Agriculture Organisation (FAO) World Reference Laboratory for Morbilliviruses, located at IAH Pirbright, we are working to develop new diagnostic tests based on the latest molecular technologies. Our group pioneered the development of tests that detect the genetic material of the virus (reverse transcription polymerase chain reaction tests; RT-PCRs). We applied these for detection and characterisation of the morbilliviruses and identified distinct strains and mapped their geographic distribution (Figure 1). This has aided the GREP in focussing attention on the remaining focus of rinderpest infection in eastern Africa. We maintain extensive collaborations with overseas laboratories in Europe, Africa and Asia and provide scientific advice and training in molecular diagnostic techniques.

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Our group also studies morbillivirus diseases of special importance to wildlife. Canine distemper virus has caused heavy mortalities in seals in Lake Baikal (Figure 4) and in the Caspian Sea, while an outbreak of phocine (seal) distemper which occurred in northern European seals in the summer of 2002 killed more than 20,000 animals. Other morbilliviruses isolated from cetacean species - dolphins, whales and porpoises - have been linked to the deaths of thousands of dolphins in the Mediterranean Sea in 1990 and with mass strandings of other cetacean species. Again, in summer 2007, this virus is circulating with devastating effects in Mediterranean whales and dolphins.

The Morbillivirus Group has an active research programme investigating the molecular determinants of pathogenesis and host range using reverse genetics, a technique first developed for rinderpest in our laboratory in 1996 and more recently for PPRV. We have been able to demonstrate that the rinderpest vaccine, which is safe and highly efficacious, has multiple gene mutations that explain its high attenuation and stability, and that the 3' and 5' promoter regions also play an important role in determining the pathogenic nature of the virus. We are now using this technology to develop marker vaccines for these viruses, so that vaccine virus can be distinguished from field infections.

Publications:

  • Baron, M.D. and Barrett, T. (2000) Rinderpest viruses lacking the C and V proteins show specific defects in growth and transcription of viral RNAs. Journal of Virology, 74, 2603-2611 [abstract]. 
  • Dhar, P., Sreenivasa, B.P., Barrett, T., Corteyn, M., Singh, R.P., and Bandyopadhyay, S.K.(2002) Recent Epidemiology of Peste des Petits Ruminants Virus (PPRV). Veterinary Microbiology, 88, 153-159 [abstract]. 
  • Das, S.C., Baron, M.D. and Barrett, T. (2000) Recovery and characterisation of a chimeric rinderpest virus with the glycoproteins of peste des petits ruminants virus: Homologous F and H proteins are required for virus viability. Journal of Virology, 74, 9039-9047 [abstract].  
  • Ngichabe, C.K., Wamwayi, H.M, Ndungu1, E.K., Mirangi1, P.K., Bostock, C.J., Black, D.N. and Barrett, T. (2002) Long Term Immunity in African Cattle Vaccinated with a Recombinant Capripox-Rinderpest virus Vaccine. Epidemiology and Infection, 128, 343-349 [Abstract].