Ileitis has been around for a long time, but it didn’t really emerge as a disease until pigs were brought inside in the 1970s, when it became more prominent, says Dr. Kent Schwartz, senior clinician at the Iowa State Veterinary Diagnostic Lab in Ames, Iowa. He explains that clinically, pigs can suffer a variety of consequences, from mild to severe diarrhea, stunted growth, and even acute bloody diarrhea or death.
According to Managing Pig Health (2nd Ed.), ileitis is associated with changes in the intestines. It is seen in four forms: bloody gut or proliferative hemorrhagic enteropathy (PHE), porcine intestinal adenopathy (PIA), necrotic enteritis (NE), and regional ileitis (RI). “All are uncommon in maiden and pregnant gilts,” notes the textbook by Muirhead, Alexander and Carr.
“In lay terms this condition is often described as bloody gut because there is acute hemorrhage into the lower part of the small intestine and, occasionally into the upper part of the large intestine,” write the authors.
The disease is caused by a bacterium, Lawsonia intracellularis. A pig with bloody gut may appear pale and weak, with bloody or dark feces or found dead, according to Managing Pig Health. It says, “Post-mortem examination showing massive hemorrhage in the lower intestine is strongly suggestive of this disease.”
Dr. Schwartz has seen many cases of ileitis. He explains the disease is easily spread by fecal-oral routes from a contaminated environment. It is found on almost all farms in the United States and up to one-third of all pigs will have intestinal lesions caused by the disease at some point in their lives. Adult animals, including those in the breeding herd, act as carriers and can transfer ileitis to younger animals, which continues the cycle of infection.
D. Schwartz notes that the economic impact of ileitis can be significant, both in terms of clinical and subclinical cases. Clinical impact of the disease can run from $2-10 per head; subclinical cost in reduced performance, increased feed costs and impact on carcass quality can run another $2-10 or more per head. Although antibiotics are effective against ileitis, Dr. Schwartz feels it’s not prudent to keep a pig on antibiotics all of its life and since the mid-1990s, there has been an effective vaccine.
“The intercellular nature of the disease requires a cell mediated response rather than just antibody, which doesn’t seem to have a lot of effect on preventing infection,” he explains. “Modified live vaccine, on the other hand, provides a more effective immune response, leading to a higher and longer level of protection of the pig.”
In managing ileitis, Dr. Schwartz says the prevention step is much more important and effective than continually treating with feed antibiotics. “Ongoing prevention of ileitis through the strategic use of vaccine has several advantages in that we harness long term natural immunity in pigs and on the sow farm.”
In addition, the new Veterinary Feed Directive will have major impact on how producers treat ileitis with antibiotics. “Ileitis is one of the main reasons antibiotics are used in grow-finish. I think we’ll see vaccine used much more going forward as a management tool to prevent ileitis rather than the use of feed antibiotics,” says Dr. Schwartz.
Dr. Schwartz provides additional details on the clinical signs of ileitis, impact on the pig and ways to more effectively manage the disease in this video.