Porcine Epidemic Diarrhea (PED) Facts

By Dr. Dean Koehler
By now, everyone associated with the U.S. swine industry has heard about the Porcine Epidemic Diarrhea (PED) outbreak that first hit the United States in mid-April.  This disease is caused by the Porcine Epidemic Diarrhea virus (PEDv).

The severe diarrhea, vomiting and dehydration symptoms of PED are indistinguishable from TGE, which is also caused by a coronavirus.  Because of the similar symptoms, early outbreaks of PED were often incorrectly attributed to TGE.  PED causes high mortality (50 to 100 percent) in piglets younger than three weeks old, with mortality rates decreasing significantly as age increases.  For instance, most sows become ill, but quickly recover.

In a presentation at the World Pork Expo, Dr. Greg Stevenson of the Iowa State University Veterinary Diagnostic Laboratory reported that, as of that time, at least 103 separate sites in the U.S. had confirmed positive diagnoses for PED.  These positive reports were accumulated from among samples submitted to the four labs that currently have PEDv testing capabilities; namely, Iowa State University, University of Minnesota, Kansas State University and South Dakota State University.

The disease has a wide geographic spread with confirmed cases in Iowa, Minnesota, Indiana, Illinois, Ohio, Michigan, Missouri, Oklahoma, South Dakota and Colorado.  Iowa and Minnesota are the states with the highest number of confirmed cases, with 60 and 15 confirmed positive sites, respectively.   However, it should be noted that these numbers under-report the full extent of the disease as pork production systems generally stop submitting samples from sites once PED is found within their pig flow.

The ISU Diagnostic Lab first became aware of the disease via samples submitted on April 29 from an Iowa location.  They have retrospectively analyzed 80 previous submissions to their lab that were suspected to be TGE and discovered two previous positives – an Ohio sample submitted the week of April 15 and an Indiana sample from the week of April 22.

PEDv is believed to have originated in Asia (Thailand and China) and has been present in Europe since 1971.  It has not yet been determined how the virus first appeared in the U.S. nor is it known how the virus quickly spread to such a wide geographic area.  Fecal-to-oral transmission is the known method of virus transfer, so strict adherence to biosecurity protocols is essential to limiting the spread of the disease. PED is slightly more durable than the TGE or PRRS viruses, but it can be killed or inactivated by many common disinfectants, temperature (greater than 140° F for 30 minutes), and drying.

The American Association of Swine Veterinarians (AASV) has stated that no evidence in the current scientific literature shows that the disease can be transmitted through feed or feed ingredients.  The industry received some initial reports of a positive feed test at the Minnesota Veterinary Diagnostic Lab, but that incident proved to be a false positive according to subsequent testing.

Vita Plus is communicating with industry experts such as the AASV, university labs and the USDA to gather information and provide facts to our customers.  We will share additional information as we learn more. Feel free to contact your Vita Plus consultant if you have questions about PED and its impact on your pork production business.  Here are some additional PED links that may be of interest to you:

• Iowa State University PED Fact Sheet
• Iowa State University PED Diagnostic Testing
• University of Minnesota PED Fact Sheet
• University of Minnesota PEDv Testing of Feeds
• University of Minnesota PED Stability
• Association of American Swine Veterinarians PED links page

About the author:  Dr. Dean Koehler has served as swine technical services manager since joining Vita Plus in 2001.  He was raised in southwest Minnesota and was active in 4-H and FFA.  His youth livestock projects included raising and showing swine and sheep.  Koehler earned his bachelor’s degree in animal science and his master’s degree and Ph.D. in swine nutrition from the University of Minnesota.  His master’s research investigated the digestibility of raw soybean varieties naturally low in anti-nutritional factors when fed to growing pigs.  His doctorate research utilized a stable isotope of the amino acid lysine to measure how efficiently sows transfer dietary lysine into their milk.  Koehler is interested in all facets of swine nutrition.  His role at Vita Plus is to provide technical service to the field and supervise the development of support tools, such as technical bulletins and spreadsheets.  Additionally, he is the author the Vita Plus online grow-finish feed budgeting software, mentor.