WOOSTER, Ohio – Food animal health researchers with Ohio State University’s College of Food, Agricultural, and Environmental Sciences are looking for a unique way to test and trace the spread of porcine epidemic diarrhea virus (PEDV).
The swine disease was found for the first time in the U.S. in April, and has since impacted hundreds of hog operations in 15 states, including Ohio and Indiana.
So far, 346 cases of PEDV have been confirmed since mid-May, with the most found in Iowa and Oklahoma.
Six month project
Funded by the National Pork Board, virologists Linda Saif and Qiuhong Wang are working on a six-month project that involves growing the virus in the lab and using this material to develop a serological test, which will allow scientists to determine how widespread PEDV is in the U.S. swine population.
Nationally, the National Pork Board directors voted to invest an additional $350,000 toward research and education to better understand PEDV. This increase in funding is in addition to $450,000 announced in June bringing the total checkoff dollars invested to $800,000.
“Serology allows you to trace the history of the outbreak through antibodies,” said Saif, an international expert on viral diseases of swine and cattle and a distinguished university professor in the college’s Food Animal Health Research Program.
“This is very important in this case because we don’t know how and where PEDV got into the U.S., and how it is spreading across state lines.”
PEDV is spread in a fecal-oral manner. As such, pork producers, handlers and transporters are urged to follow strict bio-security measures. Special care needs to be taken to wash adn completely disinfect transport vehicles.
If a pork producers suspects PEDV, they should immediately consult a veterinarian, since fast action in identification, containment and biosecurity can stem its spread.
Growing the virus in cell culture and developing a serological test are also important steps for the future development of a vaccine against PEDV, Saif said. Currently, there is no vaccine or treatment for the disease. Biosecurity measures are the only way to protect herds.
PEDV belongs to the coronavirus family, which is known to cause respiratory and intestinal diseases in mammals and birds. It has been present in Europe since the 1970s and in Asia since the 1980s.
PEDV causes intestinal disease in swine, especially young pigs. It is transmitted via feces or insects contaminated with feces. PEDV does not sicken humans and does not impact the safety of pork products.
“The entire U.S. swine population is at risk of this disease because it doesn’t have any immunity to the virus,” Saif said. “We have seen 50-100 percent mortality in baby pigs. Adults pigs only show mild illness, but the problem is that the pigs can become carriers of the virus and spread it to other pigs.”
Difficult to identify
Saif said PEDV is difficult to identify because its symptoms, which include vomiting, diarrhea, poor appetite, dehydration and depression, are almost identical to those of transmissible gastroenteritis virus (TEGV), another coronavirus that Saif has researched extensively and which has been present in the U.S. since the mid-20th century.
“The only way to tell these two viruses apart is through laboratory testing,” Saif said. “Producers and veterinarians who observe these symptoms are being encouraged to submit samples for testing so that we can better determine the extent of the outbreak.”
Combatting new disease
Saif said having enough PEDV samples available is also important for researchers such as she and Wang who are working on ways to learn more about and combat this new disease.
“This virus is difficult to grow in the lab,” she said. “We need all the samples we can possibly get.”
Ohio producers and veterinarians can submit samples to the Ohio Department of Agriculture’s Animal Disease Diagnostic Laboratory, which has PEDV tests available and has been instrumental in providing Saif and Wang with virus material to conduct their research.
County fair precautions
Saif added that swine producers are not the only ones that should be vigilant about PEDV.
“With fair season upon us, fair boards and 4-H clubs need to take precautions and monitor for the disease,” Saif said. “You will have a conglomeration of animals from many different farms coming together at one place, and people going back and forth. This could help spread the disease among pigs even further.”
Stop its spread
Researchers have already found the virus present on the surfaces of truck and animal chutes, so having strict transportation bio-security is critical to stopping its spread.
“Many questions remain unanswered about PEDV, including how it entered the U.S. and the precise number of pigs that have become infected,” said Dr. Paul Sundberg, vice president of science and technology at the National Pork Board.
“What’s important to keep in mind is that PEDV is not a human health issue, but rather a pig production disease and we know that enhanced biosecurity measures are extremely important in containing the virus.”
The American Association of Swine Veterinarians advises producers to follow these recommendations to decrease the chances of their herds becoming infected:
- Pay particular attention to anything sourced internationally, including feed ingredients of foreign origin.
- Be diligent about personnel who have traveled abroad and visitors from overseas who may be carrying the disease.
- Limit traffic (people and equipment) onto the farm.
- Thoroughly clean and disinfect anything coming onto the farm, especially animal transport vehicles.
- Take care when disposing of dead stock, particularly if using a communal disposal method.
- Isolate newly arriving animals and continue vet-to-vet discussions about animal health at the herd of origin.
- When visiting a site or packing plant, transporters should wear coveralls and boots to prevent contamination in the cab of the trailer and to minimize exposure to other pigs.
- Establish a “clean” and “dirty” zone for farm and transporter works to follow during load-in and load-out.
- Clean and disinfect trailers after use. This is especially important when going to commingled sites such as cull depots, packing plants or buying stations.
- Remove dirty shavings, manure and other debris. The use of a detergent soap can help to break down dried manure and speed up the wash process. After cleaning the trailer, use a disinfectant according to label directions to kill the virus.
- Wash coveralls, boots and other equipment when transporting pigs and cleaning the interior of the tractor cab to remove any dirt or shavings.
- Once clean, park the tractor and trailer in a secure location away from other vehicles traffic to dry.