PEDV positive feces (PEDV negative feces for the Negative Control group) were spread evenly on a concrete coupon modeled after the non-slip “waffle” flooring commonly found in swine packing plant unloading docks. Eight treatment groups evaluating two concentrations of AHP disinfectant (1:32 and 1:64), two concentrations of CD disinfectant (100 ppm and 50 ppm), and two temperatures (20⁰C and -10⁰C) were evaluated using a fixed level of fecal contamination (10 ml) and contact time (5 minutes). For the treatment groups evaluated at -10⁰C, the AHP and CD disinfectants were mixed into a solution that was 10% propylene glycol (PG), to prevent freezing. A negative control and positive control group were also evaluated. The positive control group was sham disinfected with a sterile water / PG solution. Each treatment group consisted of four replicates (4 concrete coupons and 4 pigs per treatment). After disinfectant application, the contents of the concrete coupons were re-collected and administered to 3-week old pigs through a gastric tube. Each coupon was matched to an individual pig that served as a swine bioassay to determine if the PEDV was still infectious after disinfectant treatment. Infectivity was determined by detection of PEDV with reverse transcriptase polymerase chain reaction (RT-PCR) quantitation on rectal swabs collected from pigs 3 and 7 days after inoculation. Pigs in each treatment group were housed individually in raised tubs.
The positive control pigs failed to become positive through swine bioassay; therefore, the results from this study are inconclusive and cannot be used to determine the effectiveness of either the AHP or CD disinfectants at inactivating PEDV in swine feces on concrete surfaces.
Dr. Derald Holtkamp DVM, MS
Associate Professor, Iowa State University College of Veterinary Medicine
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