Drs Judy Bettridge and Dan Bray collecting samples at a pig farm in Norfolk, UK | Photo: S Belmain
Drs Judy Bettridge and Dan Bray collecting samples at a pig farm in Norfolk, UK | Photo: S Belmain

On farms, rodents consume and spoil animal feed, damage infrastructure and are a considerable threat to animal health and to achieving optimal health and wellbeing recognising the interconnections between people, animals, plants and their shared environment, an approach known as ‘One Health’. Rodents can cause direct stress to pigs and poultry but are mainly important as carriers of pathogens. In pigs, this includes serious diseases like Swine dysentery, Aujeszky's Disease, PCV2 (Porcine circovirus 2) and Encephalomyocarditis.

Wild brown rats can carry Influenza A and might act as an intermediate host for the transmission of avian influenza between wild birds and poultry. For other diseases like African Swine Fever, rodents may support ticks that can carry it, or act as mechanical reservoirs – whereby they spread the disease without being infected by it. Rodents also play a role in the epidemiology of leptospirosis (Weil’s disease) and salmonellosis, or in spreading antibiotic-resistant bacterial strains such as livestock-associated MRSA. Rodents can pick up infections from pigs or poultry and spread them within and between farms, they can act as a bridge between wild fauna and livestock, and they can maintain the infection locally when a farm is emptied and decontaminated after a disease outbreak or livestock turnover. Some of these diseases can go on to infect humans, for example new strains of influenza, or rodents could facilitate the spill-over of novel diseases or future pandemics.

Thus, there are very good reasons for rodent management on pig and poultry farms. An important approach has always been the use of rodenticides. However, concerns about the environmental safety of the most common rodenticides have led to changes in European and national regulations that restrict their use and pose new challenges for efficient rodent management on farms. There is also the problem of resistance against these poisons.

NRI is part of a European consortium investigating the role of rodents in spreading diseases on livestock farms and developing future strategies to protect farm animals from rodent pest problems, through a research project known as ‘RodentGate’ (Future rodent management for pig and poultry health). Consortium partners include the University of Antwerp, Belgium, the Dutch Pest & Wildlife Expertise Centre, the Netherlands, Julius Kühn Institute, Germany and the National Veterinary Research Institute, Poland.

Led by Professor Steve Belmain, the NRI team includes Drs Judy Bettridge, Dan Bray, Sophie Bouvaine and Gonçalo Silva, who will be looking at how different farm-rearing practices may impact on the prevalence of rodent-borne diseases, trying to link farm activities with disease incidence and getting a better understanding of rodent movements and interactions with farm animals. A better understanding of the eco-epidemiological dynamics of rodents and livestock is expected to lead to more sustainable rodent management methods, with reduced reliance on using poisons.

RodentGate is supported by the ERA-NET fund for International Coordination of Research on Infectious Animal Diseases; NRI’s funding comes directly through UKRI (BBSRC).