RESEARCH: Powder disinfectant effective against PRRS virus

//01 May 2012 The use of a powder disinfectant has been proven to work as a good alternative to increase biosecurity in hog operations. This was shown in research by the University of Minnesota. The researchers were interested in making a comparison with a liquid disinfectant as liquid boot baths, utilised in many hog operations, have their limitations in keeping farms PRRS free. Problems arise from the current use of liquid disinfectant boot baths including their effectiveness following con­tamination with faecal matter and in freezing temperatures. The objective of the study therefore was to test a powder disinfectant, as an alternative to a liquid disinfectant boot bath, for the deactivation of PRRS virus under various temperatures and in the pres­ence or absence of faecal matter. Trials In Trial 1, clean, 24 dry rubber boots were randomly assigned to one of two treatment groups. Treatment groups consisted of boot baths containing either the powder disinfectant Stalosan F power (Vitfoss, Denmark) or Synergize liquid disinfectant (Pro-Ag; Winnipeg, Manitoba, Canada), following the manufacturers’ instructions at an environmental temperature of 85 degrees F (29.4 degrees C). After having made sure that PRRSv was absent on the booths, 1 ml Ingelvac PRRS MLV was added to 99 ml of sterile water and inverted and reverted for 5 minutes to mix completely. 2 ml of the dilution was applied with a syringe to the bottom of each boot. The inoculated boot was then sampled and tested. In Trial 2, the environmental temper­ature was 8°F (-13.3 degrees Celsius, a temperature below the freezing point of the liquid disinfectant). The same method used in Trial 1 was re­peated at this temperature. Trial 3 was conducted in field con­ditions to demonstrate the use of the powder in summer conditions and in the presence of faecal matter. Results In trials 1 and 2, 260 samples were collected and tested by PCR for the presence of PRRSv. Neither of the products tested resulted in 100% PRRSv PCR negative results under all conditions. The presence of faecal matter significantly reduced the ef­fectiveness of the liquid disinfectant but had no significant effect on the powder disinfectant. In the absence of faecal matter, the liquid disinfectant appeared to be more effective compared to the powder disinfectant. At -13.3 degrees Celsius and at 29.4 degrees Celsius, the powder disinfectant showed no significant difference in effectiveness with or without faecal matter. In trial 3, all boots sampled tested PCR negative for PRRSv, indicating that the powder disinfectant showed effectiveness in real nursery conditions in the presence of vaccine virus infection and shedding. Related websites: University of Minnesota Vitfoss Boehringer Ingelheim Pro-Ag