An evaluation of ultraviolet light (UV254) as a means to inactivate porcine reproductive and respiratory syndrome virus on common farm surfaces and materials

A study was conducted to assess the effect of UV254 on the concentration and viability of PRRSV on surfaces and materials commonly encountered on swine farms. A standard quantity (5 × 106 TCID50, total dose) of a PRRSV modified live vaccine virus was inoculated onto 2 matched sets of surfaces/materials including wood, plastic, latex, rubber, styrofoam, metal, leather, cloth, concrete, cardboard, glass and paper. One set was exposed to UV254 radiation (treatments) and the other to incandescent light (controls) for a 24 h period. During this time, treatments and controls were swabbed at 10 min intervals from 0 to 60 min post-inoculation (PI) and again at 24 h PI. The quantity of PRRSV RNA on each item at each sampling time was calculated by RT-PCR and the presence of viable PRRSV in each sample was determined by swine bioassay. A significant reduction (p < 0.0001) in the quantity of PRRSV RNA was demonstrated at 24 h PI independent of treatment. In addition, a significant reduction (p = 0.012) in the number of UV254-treated surfaces which harbored viable virus was observed at 60 min (0/12 positive) when compared to control surfaces (5/12 positive). In addition, all UV254 treated samples collected between 10 and 50 min PI were bioassay negative. These results suggest that UV254 is an effective means to inactivate PRRSV on commonly encountered farm surfaces and materials and inactivation can be accomplished following 10 min of exposure.