Evaluation of the infectivity of porcine epidemic diarrhea virus on swine vehicles after cleaning and disinfection

TL;DR

This study assesses the infectivity of porcine epidemic diarrhea virus (PEDV) on swine vehicles post-cleaning, highlighting variable cleaning efficacy and emphasizing the importance of effective biosecurity measures to prevent disease spread.

Contribution

It provides empirical evidence on PEDV infectivity on vehicles after cleaning and disinfection, demonstrating the need for improved cleaning protocols in the swine industry.

Findings

PEDV can remain infectious on vehicles after cleaning.

Infectious PEDV was found inside vehicle cabins, causing disease in piglets.

Cleaning efficacy varies significantly across vehicle types.

Abstract

Biosecurity measures enforced by the swine industry are in place not only to protect a single farm, but also the vast community of interconnected swine farms. Vehicles play a role in disease movement and given that most pigs move throughout the system multiple times during their lives, vehicle cleanliness is key to preventing disease spread. The objective of this study was to determine the infectivity of PEDV on various swine industry vehicles and evaluate the associated cleaning and disinfection (C&D) methods. Viral swabs were collected from various locations on swine industry vehicles and were used to make the bioassay inoculums which were given to a total of 54 piglets enrolled across two bioassays: a pilot bioassay to ensure the samples were collected and stored in a way that preserved the virus, and a full bioassay testing samples collected from vehicles post C&D. The piglets enrolled in the pilot bioassay tested positive for PEDV within 48 hours, confirming the methods were appropriate and capable of infecting piglets with PEDV. From the full bioassay, the piglets inoculated with samples collected from inside the pigs-to-market vehicle cabins experienced severe diarrhea and tested positive for PEDV. No other experimental treatment group experienced persistent clinical symptoms of PEDV in the full bioassay, suggesting the concentration of infectious PEDV remaining after C&D was not enough to cause severe PED in healthy piglets. However, the cleaning efficacy varied greatly across vehicle types, suggesting that producers should continue to uphold and improve vehicle C&D.