Study identifies risk factors for spread of FMDV in Asia

An international project led by scientists in the World Reference Laboratory for Foot-and-Mouth Disease (WRLFMD) at The Pirbright Institute has tracked the evolution of foot-and-mouth disease virus (FMDV) over nearly 20 years to reveal how different factors affect its spread across countries of Western and Southern Asia.

In their study, published in Molecular Biology and Evolution, the researchers analysed nearly 2,500 viruses of three FMD serotypes (O, A and Asia1) circulating in Western and Southern Asia between 2001 and 2018, documenting important evolutionary events driving patterns of virus infections in the region.

A key finding was the recognition that certain countries in Southern Asia play a central role in the creation of new virus variants that subsequently spread in a westerly direction across the region.

The study also showed that the “molecular clock” that drives evolutionary changes in FMDV is similar across different serotypes. This clock generates virus variants that are genetically different from the original serotypes, which are introduced in waves that typically lasted three years in the study region. The scientists suggest that this oscillatory pattern is influenced by three key factors: immunity, since this is specific to each virus type, the “fitness” of these viruses to replicate and be transmitted in livestock and the opportunities for the virus to spread through international trade.

Dr Antonello Di Nardo, lead author of the paper at Pirbright, said: “Our work highlights the importance of data-sharing and exchange of samples between countries where FMD is endemic. These results offer vital insights about the spread of FMD across Asia, which has been influenced not only by factors such as geography and trade, but also by differences in the way that FMD viruses evolve and are transmitted between cattle and sheep. Our results help us to understand the risks of FMD spread between countries to enable improved prevention and intervention strategies to be implemented.”

The study was funded by the Department for Environment, Food and Rural Affairs (Defra), the Biotechnology and Biological Sciences Research Council (BBSRC), part of UKRI and the European Commission for the control of Foot-and-Mouth Disease (EuFMD).

Article: Nardo, A. D., Ferretti, L., Wadsworth, J., Mioulet, V., Gelman, B., Karniely, S., Scherbakov, A., Ziay, G., Özyörük, F., Parlak, Ü., Göktuna, P. T., Hassanzadeh, R., Khalaj, M., Dastoor, S. M., Abdollahi, D., Khan, E. U., Afzal, M., Hussain, M., Knowles, N. J., King, D. P. (2021). Evolutionary and ecological drivers shape the emergence and extinction of foot-and-mouth disease virus lineages. Molecular Biology and Evolution, msab172, advance online publication, doi: 10.1093/molbev/msab172

[SOURCE: The Pirbright Institute]