An evaluation of Stalosan F powder for deactivation of PRRSv Casey Rabbe 1 ; Deb Murray, DVM 2 ; Amanda Sponheim 3 , DVM 1 University of Minnesota, St. Paul, Minnesota; 2 New Fashion Pork, Jackson, Minnesota; 3 Boehringer Ingelheim Vetmedica Inc., St. Joseph, Missouri Introduction Preventing the spread of PRRS virus (PRRSv) between groups of pigs is a major goal of pork producers. Many hog operations utilize liquid disinfec- tant boot baths as a part of biosecuri- ty protocols aimed at minimizing the spread of PRRSv. Several problems arise from the current use of liquid disinfectant boot baths including their effectiveness following con- tamination with fecal matter and in freezing temperatures. The objective of this study was to test Stalosan F, a powder disinfectant, as an alternative to a liquid disinfectant boot bath, for the deactivation of PRRSv under various temperatures and in the pres- ence or absence of fecal matter. Materials and methods In Trial 1, clean, dry rubber boots (n = 24) were randomly assigned to one of two treatment groups (12/trt). Treatment groups consisted of boot baths containing either Stalosan F power (Vitfoss; Graasten, Denmark) or Synergize liquid disinfectant (Pro- Ag; Winnipeg, Manitoba), following the manufacturers’ instructions at an environmental temperature of 85° F. The entire bottom of each boot was first wiped with a Swiffer Sweeper pad soaked in 30 mL of a 2:3 dilu- tion of deionized water to neutral- izing broth. After sampling, each pad was squeezed into a plastic bag, and 10 mL were withdrawn using a pipette. The fluid was then placed in a collection tube and analyzed by PCR to verify absence of the virus. This technique was used for all testing performed dur- ing this trial. Additionally, each boot was placed in the respective treatment boot bath and again Swiffer sampled and tested by PCR to verify the ab- sence of PRRSv in each bath prior to the start of the t rial. 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 1:100 dilution of re-constituted Ingelvac PRRS MLV vaccine was applied with a syringe to the bottom of each boot (Figure 1). The inoculated boot was then Swiffer sampled and tested by PCR to confirm presence of the virus. Inoculated boots were consecutively placed in each boot bath per treat- ment group, to simulate on farm Figure 1: conditions. The boots were Swiffer sampled and tested by PCR 1 min. post-disinfection (Figure 2). This dilution for inoculation was chosen approximating a typical infectious dose of PRRSv via oral and intrana- sal routes. 1 The sensitivity of PRRSv PCR testing at this dilution of vac- cine plus neutralizing broth and method of collection were validated by submission of 5 positive inocu- lated samples to two independent diagnostic laboratories. 2 mL of Ingelvac PRRS MLV vac- cine of the same dilution was ap- plied to a quarter cup of confirmed PCR negative fecal matter and mixed (Figure 3). Fecal matter was then applied to the bottom of each boot (Figure 4), Swiffer sampled, American Association of Swine Veterinarians 97
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