Ileitis organism widespread
Ileitis is an enteric disease caused by Lawsonia intracellularis. This disease is present worldwide. In the United States, as many as 90% of farms have at least one pig infected with the bacteria, as indicated by serology. While not every scouring pig has ileitis, it may be the most common infectious cause of enteric loss in the finisher.
Where does ileitis “live”?
Lawsonia lives in the cells lining the intestine. When these cells are sloughed off, the organism is shed in feces along with the cells. It can then be spread directly to pigs within the pen and barn, or indirectly on boots, trucks and other vectors to pigs at other sites. Vaccination against ileitis stimulates protection against the field organism by growing within these same intestinal lining cells, letting the pig learn to control growth of both the vaccine and field organism.
Testing for exposure
Several tests are available to identify if Lawsonia is present, and to pinpoint the age when pigs are infected. Serology, using the IFA test, will demonstrate exposure starting 14 - 21 days after infection. The Polymerase Chain Reaction, or PCR test, looks for the bacteria itself in feces (fecal PCR) or tissues (post mortem ileum or large intestine samples).
With the information regarding exposure timing, vaccine can be placed properly. Pigs should receive vaccine approximately four weeks prior to exposure. A longer period is also acceptable. This allows the immune system time to develop protective immunity from vaccination prior to exposure. In this way, prevention is the simplest, surest way to protect pigs against ileitis over time. Feed medications should be withdrawn for three days before and after vaccination to prevent damage to the live vaccine.
Management controls
Other management activities can help limit exposure to the ileitis organism. The following have been identified for Lawsonia directly, or for enteric disease in general.
- Use all-in/all-out pig flow to allow for cleaning and disinfecting between groups
- Maintain an older parity sow herd to reduce the number of positive weaned pigs
- Use boot brushes and hoses with nozzles to clean boots between barns
- Minimize the number of sources of pigs per finishing barn
- Reduce pig density and contact with other animal species
- Minimize temperature fluctuation within barns
Reducing the impact of ileitis is becoming simple and repeatable. Using vaccination, with good management, problems associated with ileitis can be a thing of the past in any swine operation.
More information
Bronsvoort M, et al. Management factors associated with seropositivity to Lawsonia intracellularis in US swine herds. J Swine Health Prod. 2001; 9(6):285-290. www.aasv.org
Collins A, et al. Studies on the ex-vivo survival of Lawsonia intracellularis. J Swine Health Prod. 2000; 8(5): 211-215. www.aasv.org
Funk JA, et al. Risk factors associated with Salmonella enterica prevalence in three-site swine production systems in North Carolina, USA. Proc 4th Salinpork 2001. Pp. 75-77. www.salinpork2001.com