#15-121

Complete

Date Full Report Received

03/11/2016

Date Abstract Report Received

03/11/2016

Contaminated swine transport vehicles played a role in the rapid spread of porcine epidemic diarrhea virus (PEDV) across the United States in 2013. One potential source of contamination for livestock trailers is the unloading dock at swine packing plants or harvest facilities. Therefore, quick, practical, low cost methods of swine packing plant unloading dock sanitation need to be developed to prevent possible trailer contamination in the future. The objective of this study was to test the efficacy of an accelerated hydrogen peroxide (AHP) disinfectant and a Chlorine Dioxide (CD) disinfectant at inactivating PEDV in swine feces on concrete surfaces with a very short contact time under both warm (20ºC) and cold (-10ºC) conditions.

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.

Contact information for correspondence:
Dr. Derald Holtkamp DVM, MS
Associate Professor, Iowa State University College of Veterinary Medicine
Business: (515) 294-9611
Mobile: (515) 520-1040
2233 Lloyd Veterinary Medical Center
1809 S Riverside Dr.
Ames, IA 50011-1250