Porcine Epidemic Diarrhoea virus (PEDv) might be present in farrow-to-wean farms between two to four days prior the first appearance of clinical signs.
This changes the ideas of identifying potential sources of contamination. Previously, one to two days was thought to be the average time prior to clinical signs. This conclusion was shared by Dr Laura Greiner at the International Pig Veterinary Society (IPVS) Congress, held June 8-11, 2014, in Cancún, Mexico.
Greiner, a veterinarian at Carthage Innovative Swine Solutions, in Carthage, IL, United States, said that on the basis of her findings, the virus appears to move throughout the facility before it reaches a threshold for clinical disease presentation.
She presented her findings of an analysis of environmental samples from 12 farms using a Swiffer collection method. In five of them, PED virus broke out.
The areas tested were:
She said, “Three of the five farms that contracted PEDv were originally classified as low risk. Two of the five farms were filtered farms. Of the five farms that developed PEDv, four of the five farms were found to have either suspect or positive samples three days prior to the onset of clinical signs. The other farm did not have positive findings until the day of the clinical symptoms.”
She continued, “The findings of the survey demonstrate that in this case, the fomites/ food belonging to the animal caretakers do not appear to be the source of contamination in these cases. The fact that multiple testing areas within a farm are testing positive/suspect prior to actual clinical symptoms indicate that the virus is present on-site at low levels approximately 48 hours prior to identification of clinical symptoms and appears to be moving throughout the facility before it reaches a threshold for clinical disease presentation.”
Greiner concluded, “Even though the virus can cause clinical signs 12-24 hours post-exposure, these findings demonstrate the challenge in identifying the source of contamination in farrow to wean farms as it appears to be a delay of 24-48 hours post-introduction before clinical signs are detected by animal caretakers.”