What are rotaviruses?
Rotaviruses are dsRNA segmented (11), non-enveloped viruses which infect the gastrointestinal tract. They’re the biggest cause of viral gastroenteritis in children under five and increase both morbidity and mortality rates, causing 500,000 human deaths each year.
Rotavirus is also a concern to the livestock economy. It’s endemic on pig farms, where outbreaks cause poor growth performance. In pigs, rotavirus is most prevalent in neonates (under seven days) and at the time of weaning (21 to 28 days).
Infected pigs will take five days longer to reach 25kg than an uninfected pigs, making a large impact on the profitability of pig production. An outbreak of rotaviral disease on a medium-sized pig farm (approximately 500 sows) costs in the region of £15,000 due to direct losses and delays in production.
Our research and its impact
Our research team has performed a survey of group A rotavirus (GARV) strains circulating in the UK and an in-depth study of a UK pig farm, identifying a wide range of genotypes. We also found evidence of reassortment (i.e. exchange of gene segments) and transmission of virus between people and pigs.
There are two vaccines for GARV currently on the market for pigs, neither of which have proved efficacy. We’ve produced a modified live-attenuated virus vaccine strain by serial passage in cell lines, with an interferon system circumvented by introducing viral proteins from Parainfluenza type-5 virus (V protein) and bovine viral diarrhoea virus (Npro protein).
By developing this, we hope to produce a virus that is dependent on these cell lines and therefore would be weakened in normal cells. This could form the basis for an attenuated vaccine strain.