An European project on future rodent management for pig and poultry health
Apart from consuming and spoiling animal feed, and damaging infrastructure in and around farm buildings, rodents are a considerable threat to One Health. An important component of rodent control strategies has always been the use of rodenticides. However, concerns about the environmental safety of the most common rodenticides has led to changes in the European and national regulations that restrict their use and pose new challenges for efficient rodent management on farms. RodentGate, will investigate the rodent-related risks for animal health in the pig and poultry industry and how this might change with altered rodent control. RodentGate focuses on pig and poultry farms since this is where most rodent-related problems can be expected. Rodents cause direct stress effects on the livestock, but are mainly important as carriers of pathogens. For a number of economically very significant infectious diseases, rodents are replicating reservoirs and a source for transmission to pigs, e.g. Swine dysentery [1,2], Aujeszky’s Disease , PCV2 , Encephalomyocarditis [5, 6]. Wild brown rats can carry Influenza A and might act as an intermediate for the transmission of avian influenza between wild birds and poultry [7,8]. For some other critical diseases, ASF, Foot and Mouth Disease, there is little evidence of replication in rodents, but rodents may act as mechanical reservoirs; some studies outside Europe indicated rodent infestation on farms as a risk factor [9, 10]. Rodents are also hosts for soft tick species that carry ASF in parts of Europe ; a recent study also documented ASF in hard ticks . Although the epidemiology is complicated due to different host-serovar associations, the presence of Salmonella, Campylobacter and
Leptospira species in rodents, also warrants rodent control. An additional concern is the spread by rodents of antibiotic resistant bacterial strains such as livestock-associated MRSA [13, 14].
Finally, zoonoses like toxoplasmosis, echinococcosis or trichinellosis use rodents as intermediate hosts, so cases in pigs will be linked to
rodent abundance and animal production system.
Thus, there are strong animal health reasons for rodent management on pig and poultry farms. Rodents can pick up the infection from
infected pigs or poultry and spread it 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 econtaminated after a disease outbreak or livestock turnover. Apart from general farm hygiene and rodent proofing, a crucial part of current management is the use of anticoagulant rodenticides. Because of issues with safety for non-target animals and the danger of secondary poisoning of predators, the use of these compounds has been strongly restricted. There is also the problem of resistance against these rodenticides . Moreover, several EU countries are considering a near complete phasing out of all rodenticides.
Ecologically-based rodent management was coined about 20 years ago  as a strategy that combines an Integrated Pest Management
approach with a thorough knowledge of the rodent ecology, enabling interventions to be precisely pointed in time and space, whilst being ecologically and economically sustainable. This requires a very good understanding of the rodent demography, life history, space use, dispersal capacities as well appropriate documentation of pathogen presence and transmission patterns in the rodent population. Proper understanding of transmission mechanisms is crucial since killing hosts may have unexpected effects on the spreading of an infection [17, 18]. While there is a large body of literature about the ecology of rodents in the wild, the information about the aspects mentioned above is remarkably scarce for the peri-domestic rodents living on or near farms.
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