The Roles of harvest plant lairage and transportation in an outbreak of porcine epidemic diarrhea virus infection, USA.

ABSTRACT

After porcine epidemic diarrhea virus (PEDV) was detected in the United States in 2013, we tested environmental samples from trailers in which pigs had been transported. PEDV was found in 5.2% of trailers not contaminated at arrival, , suggesting that the transport process is a source of transmission if adequate hygiene measures are not implemented.

Porcine epidemic diarrhea virus (PEDV) was detected in herds of pigs in the United States during April 2013 (1). PEDV is a member of the Cornaviridae family that produces a malabsorptive diarrhea secondary to atrophy of the small intestinal villi (2). Initial clinical cases were detected in herds in Indiana and Iowa during May 2013.The virus spread rapidly across large geographic regions; 218 cases of infection were identified in 16 states during the first 9 weeks of the outbreak (3). Subsequent testing of historical samples collected during the week of April 15, 2013 identified the index herd in Ohio (3). Veterinarians became concerned about the role that facilities where pigs are harvested for processing into food and the transportation equipment used to move pigs from farms to those facilities were playing in the spread of PEDV. These concerns were based on evidence that equipment used to transport live pigs transmits another enteric coronavirus, transmissible gastroenteritis virus, between sites in the United States (J.F. Lowe, unpub. data).

Pigs are commonly transported to harvest facilities in vehicles that have not been cleaned and disinfected between loads. Implementation of “all in–all out” sites, which are sites in which pigs are grown and all pigs in a group are removed before arrival of the next group, limits the spread of disease introduced by transport vehicles. In many cases, the risks and associated costs of disease introduced late in the growing period are thought to be less than the cost of cleaning and disinfecting vehicles. Transport vehicles are often shared by different pig owners, enabling the spread of disease across large regions.

Click here for full online paper.