Ileitis continues to be challenging -- to sort out diagnostically and to prevent, treat and control.

These challenges, however, can be used as opportunities for practice building, according to swine veterinarian John Hicks, DVM. Among other things, ileitis can be used to create client education programs, help clients in problem solving, and create value‑added service for a swine veterinary practice, he says.

Hicks, with the Carroll Veterinary Clinic, Carroll, Iowa, discussed these challenges and opportunities in a paper presented last fall at the Iowa State University Swine Disease Conference for Swine Practitioners. The paper was titled: “Ileitis: Clinical Quagmire or Practice Builder?”

Hicks says that in his practice experience, pigs as young as 6 weeks of age and as old as parity 2 sows have had a diagnosis of ileitis.

He explains that ileitis can be expressed in several forms, ranging from a chronic condition causing diarrhea, ill thrift with necroproliferative enteritis (NPE), or proliferative intestinal adenomatosis (PIA), to a peracute proliferative hemorrhagic enteropathy (PHE) that results in significant mortality.

Further, he states, “subclinical ileitis is prevalent in our industry with an impact on growth performance in the absence of overt clinical signs.”

Diagnostic challenges
A significant challenge exists for correctly diagnosing ileitis, according to Hicks. Even though it has been suggested that every case involving grow‑finish diarrhea and significant variation equals ileitis, in reality, says Hicks, “sorting out the underlying cause of grow‑finish diarrhea is very complex and challenging.


Pigs as old as parity 2 sows can be diagnosed with ileitis.

“We have used this complexity as a chance to educate clients and bring to them an understanding of the need for thorough, systematic and accurate diagnostics.” This, he emphasizes to clients, requires submission of appropriate samples to the veterinary diagnostic laboratory.

Hicks says that as the pressure increases to reduce antimicrobial use in the pork industry, ileitis will need to become one of the differentials in a nursery scour outbreak along with:

  • Hemolytic E. coli
  • Salmonellosis (cholerasuis)
  • Salmonella typhimurium
  • Rotavirus
  • TGE
  • Feed‑related enteritis
  • Coccidiosis

For finishing pigs, Hicks adds, the list can be expanded to include not only the aforementioned diseases, but the following conditions as well:

  • Water-related diarrheas
  • Intestinal parasites
  • HBS/volvulus
  • Gastric ulceration
  • Spirochetal colitis
  • Swine dysentery
  • PCV‑II
  • Colonic dysbacteriosis

Case work up
In working up enteric disease cases, Hicks says he starts by collecting antemortem samples, such as rectal swabs or fecal samples for culture, Lawsonia PCR, parasite investigation and other diagnostic purposes.


Pigs as young as 6-weeks-old can also have ileitis.

“I also may collect water and feed samples for nutrient and impurity analysis,” he says. “Sacrificing one or more clinically affected, untreated pigs is critical in reaching a diagnosis. In conjunction with a thorough postmortem examination, I collect visceral organs -- liver, lung, kidney -- lymph nodes, and intestinal sections, including jejunum, ileum, cecum and spiral colon. Inclusion of other tissues, such as lung, liver, kidney, spleen and tonsil is recommended to rule in or out a comprehensive list of differential diagnoses.”

Hicks refers to a recent case that clinically suggested Lawsonia infection but also included two pigs that were disoriented and exhibiting CNS signs. “Pigs weighed 117 pounds, and 25 to 30 percent had loose to watery stools. Diarrhea had worsened over a period of two weeks.

“Fecal cultures/swabs were negative for Lawsonia by PCR and negative for hemolytic E. coli or Salmonella. Pigs had been non-responsive to tiamulin liquid in drinking water, and after 48 hours on gentamicin, the diarrhea had worsened. We sacrificed the CNS pigs and submitted tissues to the Iowa State University Veterinary Diagnostic Laboratory.

“Neither pig had gross intestinal lesions or loose colonic contents. Histo-pathology of brain revealed suppurative meningitis. Immunohistochemistry stains demonstrated abundant PCV II antigen and there was severe lymphoid depletion.”


Subclinical ileitis is prevalent in the United States pork production industry with an impact on growth performance in the absence of overt clinical signs.

Final diagnosis
The final diagnosis presented a quagmire that indicted the disease cause was most likely PCV II and dysbacteriosis, according to Hicks.  Even so, this particular case presented an opportunity as a practice building experience, Hicks says. “The client expressed the wish that he had worked the case up earlier before beginning antimicrobial trial and error.”

Cases where a  positive diagnosis of Lawsonia‑associated disease is made doesn’t simplify things, according to Hicks. “A positive diagnosis of Lawsonia‑associated disease is quite possibly where the predicament gets deeper, wider, and stickier,” he says. “We must then help our clients formulate (the best) treatment and a pre-vention strategy.”

Hicks says that most veterinarians are successful at treating an outbreak of ileitis by using approved antimicrobial products such as Tylan, Lincocin, Denagard and CTC/BMD.

Ileitis prevention, however, hasn’t been so clear cut, he says. “Traditionally, ileitis prevention has been attempted with a myriad of feed grade antimicrobial strategies, often in pulsatile, rotational or step‑down schedules.”


In conjunction with a thorough postmortem examination, samples of organs such as liver, lung, kidney and intestinal sections should be submitted to the diagnostic laboratory to help with differential diagnosis of swine enteric disease cases.

To turn ileitis prevention into a practice builder, Hicks says you must systematically and scientifically resolve a number of questions, including:

1. Which program is most cost effective for this system?

2. Can I consistently create immunity‑developing levels of exposure without putting myself at undue risk for loss of performance or acute outbreaks?

3. Am I getting side benefits from this program that are unrelated to ileitis in the form of growth promotion or respiratory disease suppression that adds value?

4. How long am I going to be allowed to use all these feed grade antimicrobials?

Hicks concludes that in his experience, ileitis has often been a quagmire in terms of an accurate diagnosis and in finding a good intervention strategy. At the same time, the challenges associated with the disease have proven to be effective in building swine practice.

Ileitis vaccine

Iowa swine veterinarian John Hicks says it would be remiss to talk about ileitis without some discussion about Enterisol® ileitis‑avirulent Lawsonia vaccine.

“What appeared to be a resounding ‘home run’ over the first year and a half (of the vaccine’s use) suddenly fell into controversy surrounding what were rumored to be widespread efficacy problems,” says Hicks. “Our clinic had many of these ‘ileitis breaks’ in vaccinated pigs.”

Hicks credits Boehringer Ingelheim Vetmedica, Inc. (BIVI), the company that markets the vaccine, for stepping up and providing assistance to address the reported ileitis breaks.

Although there are still some unanswered questions, it turned out that vaccine storage and thawing errors, and vaccine administration and timing mistakes accounted for many of the problems, according to Hicks.

Hicks says that according to BIVI’s internal investigation of case histories, 45 percent of the investigated problems were related to inadequate timing (vaccine immunity developed after field infection); 15 percent were due to misdiagnosis (Lawsonia was not involved); and 40 percent were due to incomplete immunization (caused by improper thawing, medication withholding violations, administration errors, breech in frozen product delivery or storage, etc.)

“We have been able to spin vaccination problems somewhat into a practice‑building experience by the use of both independent meetings and the BIVI‑sponsored Veterinarian Partner Program,” says Hicks.

“We looked at this situation as an opportunity to get together with clients and educate them on the principles of live oral vaccine administration in general. Live vaccines are tremendous tools with important advantages as long as we strive to use them properly.”