Abstract
Background
Porcine reproductive and respiratory syndrome virus (PRRSV) can be transmitted indirectly between infected and susceptible pigs through the contamination of inanimate objects or aerosols. PRRSV can be present on surfaces for prolonged periods, and under certain conditions of temperature, humidity and type of surface, remain viable outside the host. In the United States, the yearly epidemic of PRRSV typically begins in the fall. During the fall of 2020, the variant L1C.5 emerged and rapidly spread throughout southern Minnesota, which generated questions regarding possible transmission routes. This study aimed to investigate whether PRRSV could be detected on surfaces inside and outside pig barns housing L1C.5 variant PRRSV-positive pigs to illustrate the potential for indirect transmission of PRRSV.
Results
All (n = 26) samples from PRRSV-negative farm tested negative. Nineteen (13%) out of 143 samples from positive farms yielded positive RT-PCR results. Positive samples originated primarily from exhaust fan cones and doorknobs, followed by anteroom floor and mortality carts/sleds. Virus isolation attempted on two samples did not yield positive results.
Conclusions
PRRSV contamination can occur on surfaces inside and outside pig barns that are in frequent contact with farm personnel. Although virus isolation attempts were negative, our results illustrate the potential for PRRSV to be transmitted indirectly through contaminated materials or farm personnel. The study supports the implementation of biosecurity practices by farm personnel to prevent the introduction of PRRSV into farms and the prevention of PRRSV transmission between farms.