Prairie dog (Cynomys ludovicianus) is not a host for porcine reproductive and respiratory syndrome virus

Objective: To determine if the prairie dog is a biological host for porcine reproductive and respiratory syndrome virus (PRRSV). Materials and methods: Sixteen wild-caught prairie dogs were inoculated intraperitoneally with a high-titered mixture of wild-type local PRRSV strains, and seven animals were uninoculated controls. Serum and tissues were collected at 3- to 7-day intervals through 28 days for reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of viral RNA and determination of an anti-PRRSV immune response, using a novel ELISA to measure specific prairie dog IgG responses to nine viral polypeptides. Results: A variety of tissues were negative for PRRSV RNA at all time points in both treated and control animals. Clinical signs were unremarkable and no histopathological lesions of PRRS were observed. Sero-conversion was not observed in any animal over the 28-day study time course. Individual variation in background antibody levels and RT-PCR results were observed. Implications: Prairie dogs do not support replication of PRRSV and are not a reservoir of the virus. Quantitative RT-PCR values for PRRSV in serum and tissue samples overlap with negative background values near the limits of detection, increasing the risk of false-positive interpretations. Methods, materials, and resources for diagnostic investigation of the prairie dog are now available to the veterinary community.