Accurate diagnosis critical in managing growing pig enteric disease
Producer awareness of Ileitis (an intestinal disease caused by Lawsonia intracellularis) has increased dramatically in the last ten years. Ileitis can be either a chronic disease in growing pigs, or an acute hemorrhagic form in market weight and adult pigs. Both forms can easily be confused with other enteric diseases. Accurate diagnosis allows for understanding the true cause of disease.
What's in a name?
Ileitis, infection within the cells lining the ileum, is caused by Lawsonia intracellularis. It can also infect the cecum and spiral colon, parts of the large intestine. Other names for chronic ileitis include PPE (Porcine Proliferative Enteropathy), Garden Hose Gut (due to the thickening caused in the small intestine) or PIA (Porcine Intestinal Adenomatosis). The main clinical signs of chronic ileitis are diarrhea and poor growth rate. Market weight and breeding animals may have bloody diarrhea or simply die suddenly.
Causes of scours
The main infectious causes in growing pigs include Ileitis, salmonellosis (infection with Salmonella), swine dysentery (due to B hyodysenteriae), porcine colitis (due to B pilosicoli) and intestinal parasites. Other causes can include dietary changes, TGE virus infection, and ulcers.
Clinical signs are easily confused among the main infectious causes, as these relate to damage to the intestinal tract, not the specific organism. Ileitis and other diseases that cause bleeding predominantly damage the small intestine or stomach, producing digested blood and dark discoloration of manure. Whipworm infection is unique as it may produce red blood from bleeding in the large intestine, along with mucous.
Samples for correct diagnosis
Live animals may be bled for a serum test. The Ileitis IFA examines serum for antibodies against Lawsonia. Pigs need to be infected for at least 14 days to show positive. This test is used to detect when a group of pigs has been naturally exposed.
The fecal PCR detects the Lawsonia organisms shed in manure. Animals may be infected but not actively shedding the organism in feces, resulting in a false negative test. Select animals with diarrhea to maximize shedding and detection of the organism. Multiple animals should be sampled.
Several post mortem tests are also available. Thickening of the small intestine is a classic lesion of ileitis. Ulcers in the stomach are self-explanatory. Ulcers in the large intestine and swelling of lymph nodes may be seen with salmonellosis. Whipworms may be seen visually, or on histopathology (microscopic examination). For all cases, have your veterinarian submit manure, serum, and intestinal tissue samples for laboratory evaluation.
Investigate before you invest!
In any case of poor growth performance, investing in the proper diagnosis saves money! Vaccinations and medications can be applied to the real problem, maximizing return. In cases of scours in growing pigs, many causes look alike but have different solutions. The right diagnosis is the first step in successful control.
| Disease | Blood in manure | Clinical signs | Diagnostic Tests |
|---|---|---|---|
| Ileitis — chronic form | Possible — digested (black color to manure) | Poor performance, rough hair coat | Serology Fecal PCR Post mortem tests |
| Salmonellosis | Possible — digested | Same | Fecal culture or PCR Post mortem tests |
| Colitis | No | Same | Fecal PCR Post mortem test |
| Ulcers | Possible — digested | Same | Physical exam of stomach |
| Parasites | Possible with Whipworms — fresh/red | Same | Fecal float test Post mortem tests |
| Diet change | No | Associated with new diet/ration | Evaluate feeding records & formulation |
Diagnostics
To submit Ileitis IFA samples to the Health Management Center, please send serum in snap top tubes, with completed diagnostic submission forms. Forms may be obtained from:
Health Management Center
Boehringer Ingelheim Vetmedica, Inc.
2501 North Loop Drive, Suite 1000
Ames, Iowa 50010
Phone: (515) 296-5575
More information
Stevenson, Gregory. Differential diagnosis of diarrhea in grow-finish swine. Proceedings of the Annual Meeting of the American Association of Swine Veterinarians. 2001. Pp 359-363.
Knittel JP, et al. Diagnosis of Porcine Proliferative Enteritis. The Compendium. Jan 1997. S26-S29.