Received: Jun 05, 2025 / Accepted: Sep 08, 2025 / Published: Sep 30, 2025
African Swine Fever Virus infections have significantly impacted swine production in many parts of the world. Rodents are considered vectors of several swine disease agents but their role in ASFV transmission has not been determined. This work sought to determine whether rats could be experimentally infected with ASFV. In a pilot project prior to the experimental trial, 27 rats, mice, and shrews were trapped from 3 farms (range 7-10 per farm) with current ASFV outbreaks. These animals were euthanized, sampled, and tested for ASFV with polymerase chain reaction (PCR). None of the samples (n = 81) were PCR-positive for ASFV. The experimental trial utilized 45 commercially obtained rats (Rattus norvegicus domestica): 9 were orally inoculated with ASFV, 9 were intraperitoneally inoculated with ASFV, 18 were non-inoculated contacts, and 9 were negative controls. On each of days 7, 14, and 21 post-inoculation, 3 orally inoculated, 3 intraperitoneally inoculated, 6 non-inoculated contacts, and 3 negative control rats were euthanized, sampled, and tested for ASFV with PCR. Clinical signs did not develop in any of the rats. Body temperatures increased during week 2, but there was no difference between the inoculated and non-inoculated groups. None of the samples (blood, spleen, liver, lung, ileum) were PCR positive for ASFV. Serum tested with ELISA for ASFV antibodies was negative. Despite direct ASFV challenge, inoculated rats did not develop clinical disease symptoms or transmit ASFV to contacts. Further work is necessary to demonstrate the competence of rodents as biological vectors for ASFV transmission in swine herds.
