Swine practitioners and producers are always happy when a definite cause can be attached to a disease problem. When a new disease or condition is first observed on the farm, and then described in laboratories, it seems to garner numerous names along the way.
Such is the case with ileitis. It has been referred to as “garden hose gut,” porcine proliferative enteropathy (PPE), regional ileitis, porcine intestinal adenopathy (PIA) and porcine hemorrhagic enteropathy (PHE). However, it is the ileitis name that has seemed to “stick” in both lay and professional circles. Ileitis doesn't need to go by any other name!
Ileitis was identified in the early '90s, thanks to the efforts of diligent researchers. The pesky Lawsonia intracellularis is a small, bacterial organism that mainly infects the cells of the small intestine. Digestion and absorption can be disrupted, significantly reducing weight gain and feed efficiency. Pigs exhibit diarrhea, often reddish brown in color. Affected pigs may lose body condition and develop signs of wasting.
Another acute form exists where pigs exhibit a very hemorrhagic diarrhea, succumbing soon after onset of the signs. This should not be confused with Hemorrhagic Bowel Syndrome, which results in blood loss into the small intestine, no diarrhea and sudden death.
Two case reports highlight diagnostic methods, treatment and prevention steps.
Finishers from a three-site, 1,200-sow unit in central Indiana had brownish diarrhea at 18-20 weeks of age, occasional wasting and pale pigs. Also, we routinely observed some diarrhea in pigs 16-18 weeks of age.
We wondered if we could utilize a new serology test for ileitis to help achieve a definitive diagnosis and detect when pigs might be exposed to the Lawsonia bacteria. The idea was to target treatment to the time when exposure first could be documented.
A cross-sectional blood test was done of pigs that were 10, 15, 19, 20-22, and 25 weeks of age. Results clearly indicated that exposure had occurred in the finishers. The first positives on this serology test were in pigs 19 weeks of age and 70% of the 25-week-old pigs were positive.
Since the development of antibodies that react on this test takes two to three weeks, it appeared that exposure was at 16 weeks of age.
Tylosin at the 40 g./ton level was recommended for the finisher diet for growth promotion, in the hopes that it would also suppress the clinical ileitis. This appeared to work very well until last summer, when we noted several finishers losing condition.
Postmortems confirmed gross lesions of ileitis and the Lawsonia organisms were demonstrated with special stains on microscopic exam. The tylosin level in the targeted diet was increased to 100 g./ton indicated for ileitis. This is expected to provide improved control of the ileitis.
A second case of ileitis struck pigs finished in all-in, all-out rooms from a single-site, 600-sow unit. Pigs are sexed by room on this farm.
The ileitis clinical problem was most predictable in the gilt finishers; it was very frustrating as signs often appeared late in the finisher stage (around 200 lb.). It was severe enough that some death loss occurred.
Various medication strategies had been tried over the years. When a new, water-delivered, ileitis vaccine became available, this producer was interested in trying the product to achieve improved disease control. The vaccine is administered through medicator systems. The goal is to have all the vaccine consumed in a four-hour period.
Certain antibiotics must be avoided in the feed (or water) for at least three days before and after vaccination. Also, chlorine or other disinfectants or sanitizers cannot be in the water.
The duration of immunity for this vaccine hasn't been determined beyond seven weeks, but it is expected to be longer. Vaccination should be performed one to two months prior to seroconversion and/or clinical signs.
This vaccine must be stored in ultra-low freezers or used within two weeks of storage in older-style, non-frost-free freezers. Even in these freezers, vaccine should be maintained in original packaging with the dry ice. Storage in newer, frost-free freezers is not recommended.
Therefore, vaccine may need to be used upon receipt. Proper handling and administration are critical to assure efficacy of this tool for ileitis control.
The results in this case have been good so far; other practitioners are reporting encouraging performance with this new vaccine.
Although microbiologists may some day want to rename the causative agent of this disease, my bet is that ileitis by any other name will still be ileitis out in the pig barn.