Sub-project 4 – March 2019

Virus inactivation at different temp and humidity

Amongst other things, the SPREAD application – being developed under SP4 – models the spread of FMD virus via wind dispersion. However, wind borne dispersion of FMD virus is controversial, as although there are some case studies from Europe where it almost certainly occurred, there are many other instances where its role could not be substantiated.

The “missing link” to explain why wind dispersions might occur in some situations and not others might be the rapid inactivation of the virus during unfavourable environmental conditions. Acting on this hypothesis, SP1 developed a simple series of experimental trials. For these experiments, Jacquelyn Horsington, an SP1 team member working at the Friedrich Loeffler Institute (FLI) in Germany, exposed different FMD virus strains to nine temperatures and relative humidities by incubating a carefully measured amount of virus in a special cabinet.

These trials were very successful in demonstrating that under the most favourable conditions, the virus might remain active for up to 4 days. On the other hand, with unfavourable conditions of temperature and humidity, it might become inactive within 2 hours. The results need further analyses, but if confirmed could well solve a long-standing FMD question of why and when the virus might be readily spread by wind dispersion.