HOT WATER CAN INACTIVATE
PORCINE EPIDEMIC DIARRHEA VIRUS
The porcine epidemic diarrhea virus (PEDV) is still circulating in Ohio swine herds. Porcine epidemic diarrhea virus is an enveloped, single-stranded, positive-sense RNA virus in the same family as TGE. It was first discovered in the United States in April 2013 causing widespread death of piglets across the United States. Approximately seven million piglets died from April 2013 to April 2014.
The main means of transmission of PEDV is believed to be fecal-oral route, although some research has shown it could be transmitted through the air. More work needs to be done to prove airborne transmission. Any object coming in contact with fresh manure or stored manure from asymptomatic or sick pigs can cause transmission of PEDV. Therefore; vehicles, equipment, feedbags, clothes, boots, feed, animals and other objects can cause the movement of the virus. The likely reservoir of PEDV is believed to be clinically asymptomatic PEDV-infected finishing pigs.
The incubation period of PEDV is as short as 12 hours to as long as 4 days. The virus can spread rapidly through an entire population.
PEDV can infect pigs of all ages causing lethargic behavior, poor appetite, acute and watery diarrhea, vomiting, dehydration, and high mortality in neonatal piglets. PEDV is most detrimental to baby piglets less than 1 week old. Weaner, fattener, and adult pigs usually recover from clinical signs within one week with limited death loss.
Since several different diseases show clinical signs of diarrhea, making a proper diagnosis is critical. PEDV nucleic acid detection from fecal or intestinal samples by conventional or RT-PCR is the most frequent assay used at present because of its simplicity and speed. There are also immunochromatographic assay kits and some enzyme linked immunosorbent assays (ELISA's) that can be used on the farm to diagnose the disease within 10 minutes.
Control strategies for PEDV include immunity and prevention. Immunity can be the exposure to the virus or vaccination of sows and gilts to protect baby pigs. Prevention deals with biosecurity and inactivation of the virus. With PEDV recirculating around the state stay vigilant or increase prevention methods.
Some of the inactivation methods include application of chemical disinfectants, heat, alterations to pH, and drying. Some chemical disinfectants are corrosive to metal surfaces, hazardous to human and animal health, inactivated with organic material and water with high mineral content and require prolonged contact time. A trial was initiated looking at the effect of heated water at various exposure times to PEDV. Results showed that hot water (>169 degrees F) applied to a surface for greater than 10 seconds inactivated PEDV. Hot water treatment is another tool to decontamination where chemical disinfection is impractical or where a more rapid inactivation of PEDV is needed. The drawback to hot water treatment is the risk of scalding to humans and animals.
PEDV is not a human health risk. Pork remains completely safe to eat.
BIOSECURITY IS FIRST PRIORITY
The first line of defense in protecting your herd from Porcine Epidemic Diarrhea Virus (PEDV) is a thorough biosecurity program. But over time even the best protocols can slip. As you begin a new year and the industry faces this new virus, now is a good time to review and enhance the biosecurity measures that not only protect your herd, but ultimately help protect the U.S. hog population.
An industry-wide renewed focus on biosecurity is the best hope to control PEDV spread and reinfection, points out Lisa Becton, DVM, Pork Checkoff's director of swine health. "Most of our biosecurity practices are focused on fecal/oral disease transfer," she notes. Since PEDV is spread via feces, there is a sound biosecurity base in place. But that also means the virus can be easily spread by a wide range of vectors, which is why Becton advises producers to "be diligent about rethinking possible exposures."
While research is underway to learn more specifics about the virus, Becton suggests reviewing biosecurity protocols with your herd veterinarian and paying special attention to transport biosecurity efforts. Some of those recommendations include:
* Establish and visibly mark a "Line of Separation" that designates a separation from outside the facility to the inside area for people and pigs. There may be several such lines throughout a farm. Strictly enforce these lines and prevent unauthorized personnel (or vehicles) from continuing further into the premises.
* Restrict animal haulers' access to the truck or trailer only. Load out crews should not re-enter buildings without washing up, changing coveralls and boots first.
* Completely clean, disinfect and dry trucks and trailers, inside and out, after every use. This starts by removing all bedding and debris as well as using soap and detergent. Don't forget the cab.
* Several virucidal disinfectants can inactivate PEDV. Go to pork.org or aasv.org for listings.
* After transporting pigs, isolate and wash coveralls at a non-production site.
Talk to all service providers to ensure they understand the critical nature of PEDV and your new site-access restrictions. Don't forget to share information and spell out movement restrictions with the farm's non-production staff in; they need to understand the seriousness of PEDV as well.
Whether its people, vehicles or pigs, it's important to know the movements on and off your operation, and what exposure there may have been prior to coming to your site, says Bret Marsh, DVM, Indiana state veterinarian. "Knowing the PEDV status of an area, herd or market lets you take precautions so you don't bring the virus back home," he adds.
If you suspect PEDV exposure, contact your herd veterinarian. Submit samples to the veterinary diagnostic laboratory; instructions are available at both pork.org and aasv.org
"At the local level, producers should work closely with their swine veterinarians. They are a great resource for information and perspectives about what's going on in herds, and to make sure we don't miss a diagnosis," Marsh says. He also points to pork.org as another excellent resource for PEDV research and information. "There are numerous biosecurity fact sheets and white papers that are excellent, free, resources for producers to utilize," he says.
But even with the strictest policies and best intentions, this virulent virus may still find its way into your neighborhood. "Our entire national herd is naive to this virus so we will continue to see breaks," Marsh says.
Click here for the PED Biosecurity and Manure Fact Sheet for Producers