Understanding PED Virus Survival24 February 2014
US - Where there is hog manure, there is the potential for porcine epidemic diarrhoea virus (PEDv) to find its way into a hog operation. That’s an especially daunting fact because the virus sheds at extremely high levels and very little virus is needed to infect pigs.
“The very low infective dose of PEDv surprised me the most,” said Sagar Goyal, DVM, University of Minnesota researcher, who looked at the virus’ survivability in various environmental settings. “We proved the infectious dose of PEDv to cause disease in pigs is very low - even 108 dilution of the virus infected piglets.”
In a Pork Checkoff-funded study, Dr Goyal looked at PEDV survival in fresh feces, manure slurry, drinking and recycled water, and ground feed. Overall, he found results similar to those for TGE (transmissible gastroenteritis virus) — a related coronavirus.
Here is a summary of the results:
- Survival in fresh feces: The study evaluated PEDV survivability at three temperatures (104, 122 and 140°F) and three relative humidity levels (30, 50 and 70 per cent). The bottom line: “If faeces from infected pigs are present in the barn, the virus can survive for seven days or more,” Dr Goyal said.
- Survival in manure slurry: PEDv-infected slurry was stored at room temperature (approximately 77°F), 39 and -4°F. At room temperature, PEDv survived in manure slurry for 14 days. At 39 and -4°F, PEDv survived for 28 days, and possibly longer, Dr Goyal said, as the study did not continue beyond that point.
“So, if you use manure slurry for land application, you need to understand that the virus can survive in an infectious state for 14 to 28 days, maybe more,” he said.
- Survival in drinking and recycled water: Both water options spiked with PEDv were evaluated at room temperature over a series of weeks. The virus survived in both water sources for one week but not two. However, Dr Goyal pointed out that since the study didn’t test daily samples, survivability could extend beyond seven and up to 13 days.
- Survival in feed: The study evaluated wet and dry ground feed dosed with PEDV and stored at room temperature. PEDV remained viable in the wet feed for 28 days (again, the study did not run longer). In dry feed, the virus survived only one week. So, if contaminated feed is a concern, Dr Goyal said storing it for two weeks at room temperature will kill the virus.
“However, we don’t know if colder temperatures enhance survival,” he added. It’s also important to note that the pigs received only 15g of PEDV-spiked feed — “and pigs eat more than that, so we need to look at what happens when feeding larger quantities,” Dr Goyal said.
To read more about the PEDV environmental survivability research, click here.
ThePigSite News Desk