F18-associated Gut Edema Disease Successes, Challenges and Analyses Offered During a SHIC-AASV Webinar

Reports of difficult cases of colibacillosis that have been associated with the F-18 fimbrial antigen and leading to gut edema disease have been increasing. With up to 100% morbidity and 20% mortality on some sites, the Swine Health Information Center (SHIC) and the American Association of Swine Veterinarians (AASV) responded with a webinar, conducted by the Iowa State University (ISU) Swine Medicine Education Center on September 28, to hear directly from practitioners and a diagnostician involved in these outbreaks. In addition to the clinical signalment of the disease, the webinar included outbreak videos, postmortem findings, diagnostic workups, management successes and challenges, and ISU veterinary diagnostic lab historical data analyses. The webinar was attended by 139 participants from Austria, Canada, the Czech Republic, Germany, the Netherlands, Spain and the United States.

New Fashion Pork veterinarian, Dr. Deb Murray, opened the webinar presenting her experiences with outbreaks occurring as early as immediately after placement of newly weaned pigs to as long as four weeks later. Showing sequential videos of pigs during an outbreak along with postmortem and diagnostic results, of note was the involvement of multiple virulence factors consistent with enterotoxigenic E. coli strains, including shiga toxin, and lack of response to an F18 vaccine that had previously been effective. Compounding factors included poor water quality and, typically, lack of total depopulation of sites before placing new pigs.

Dr. Kurt Kuecker, the Hanor Company, talked about outbreaks in their systems that included a sudden 2-3% mortality spike within 24 hours along with 20-60% morbidity occurring 20-30 days post placement, which is five to seven days after shifting diets from a complex pelleted ration to a corn/soy ground feed ration. Diagnostic results included colibacillosis with multiple virulence toxins and multidrug resistance. Managing the diets to ensure that all pigs got their entire, sequenced feed budget was found to be an important factor in prevention of the outbreaks.

In analysis of ISU veterinary diagnostic data from 2017 to the present, Dr. Drew Magstadt, clinical associate professor in the diagnostic laboratory, found trends that showed a decrease in K88-associated disease but a corresponding increase in F18-associated cases over that time. At the same time, the data showed an obvious increase in some enterotoxins in F18+ cases along with a trend toward resistance to common enteric antimicrobials often used for treatment. Dr. Magstadt reminded participants the best opportunity for meaningful diagnostic results includes selecting pigs that are representative of the observed clinical disease, providing a good case history and submitting multiple tissues, including several sections of intestine, colon, liver and mesenteric lymph nodes, and brain/whole heads if edema disease is suspected.

SHIC, launched in 2015 with Pork Checkoff funding, continues to focus efforts on prevention, preparedness, and response to novel and emerging swine disease for the benefit of US swine health. As a conduit of information and research, SHIC encourages sharing of its publications and research. Forward, reprint, and quote SHIC material freely. SHIC is funded by America’s pork producers to fulfill its mission to protect and enhance the health of the US swine herd. For more information, visit http://www.swinehealth.org or contact Dr. Sundberg at psundberg@swinehealth.org.