Foot-and-mouth disease (FDM) is a disease of cloven-hoved animals with high costs in animal welfare and for production of animal products. Up to now transmission between farms in FMD-endemic areas has been given little attention. Between farm transmission can be quantified by distance independent transmission parameters and a spatial transmission kernel indicating the rate of transmission of an infected farm to susceptible farms depending on distance. The spatial transmission kernel and distance-independent transmission parameters were estimated from data of an FMD outbreak in Lumpayaklang subdistrict in Thailand between 2016 and 2017. The spatial between-farm transmission rate in Lumpayaklang subdistrict was higher compared with spatial between-farm transmission rate from FMDV in epidemic areas. The result can be explained by the larger size of within-farm outbreak in endemic area due to no culling. Inclusion of distance-independent transmission parameters improved the model fit, which suggests the presence of transmission sources from outside the area and spread within the area independent of distance between farms. The remaining distance dependent transmission was mainly local and could be due to over-the-fence transmission or other forms of contact between nearby farms. Farm size on the kernel positively effects the transmission rate, by increasing both infectivity and susceptibility with increasing farm size. From the results, we suggested more strict outbreak responses, as well as the outbreak communication to the farmers to reduce the between-farm transmission. Movement restrictions and enforced by checkpoints during the outbreak can prevent the transmission from outside and the distance-independent transmission within an area.

Animals like mink, cats and dogs are susceptible to SARS-CoV-2 infection. In the Netherlands, 69 out of 127 mink farms were infected with SARS-CoV-2 between April and November 2020 and all mink on infected farms were culled after SARS-CoV-2 infection to prevent further spread of the virus. On some farms, (feral) cats and dogs were present. This study provides insight into the prevalence of SARS-CoV-2 positive cats and dogs in ten infected mink farms and their possible role in transmission of the virus. Throat and rectal swabs of 101 cats (12 domestic and 89 feral cats) and 13 dogs of ten farms were tested for SARS-CoV-2 using PCR. Serological assays were performed on serum samples from 62 adult cats and all 13 dogs. Whole Genome Sequencing was performed on one cat sample. Cat-to-mink transmission parameters were estimated using data from all ten farms. This study shows evidence of SARS-CoV-2 infection in twelve feral cats and two dogs. Eleven cats (19%) and two dogs (15%) tested serologically positive. Three feral cats (3%) and one dog (8%) tested PCR-positive. The sequence generated from the cat throat swab clustered with mink sequences from the same farm. The calculated rate of mink-to-cat transmission showed that cats on average had a chance of 12% (95%CI 10% to 18%) of becoming infected by mink, assuming no cat-to-cat transmission. As only feral cats were infected it is most likely that infections in cats were initiated by mink, not by humans. Whether both dogs were infected by mink or humans remains inconclusive. This study presents one of the first reports of interspecies transmission of SARS-CoV-2 that does not involve humans, namely mink-to-cat transmission, which should also be considered as a potential risk for spread of SARS-CoV-2.