The Disease

Pathogenesis of L. Intracellularis

L. Intracellularis has specific infectious mechanisms, and generally appears in the growing and finishing stages.
Find out more about the virulence factors.

As an obligate intracellular bacterium, Lawsonia intracellularis has specific infection and spreading mechanisms in the host. The infection takes place through the oral route, and naïve pigs from different age groups are susceptible. However, infection is usually seen in the late nursery period and in the growing-finishing phases. Sporadically, young adults (replacement animals) develop an acute haemorrhagic form of the disease. There is no definitive explanation as to why some animals develop this acute form of the disease.

The infective dose is around 103 microorganisms (Collins et al., 2001), and the intestinal microbiota is essential for the development of the disease, as gnotobiotic pigs do not become infected when inoculated with a pure culture of L. intracellularis (McOrist et al., 1993). Studies using a dual infection with PCV2 or Salmonella sp. (Opriessnig et al., 2011; Borewicz et al., 2015) associated with L. intracellularis in commercial pigs have been conducted, but no evident synergic effect was demonstrated.

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L. intracellularis is a gram-negative rod with a sigmoid or curved shape and with a single long flagellum.

History and Etiology of ileitis

Not much is known about the epidemiology of L. Intracellularis.

Epidemiology of ileitis

The symptoms of ileitis in pigs are diverse, and include hemorrhagic or acute, chronic and subclinical.

Clinical signs and forms of ileitis

Diagnosing ileitis involves considering four important factors

Diagnosis of ileitis

Ileitis outbreaks must be treated immediately to reduce losses

Treatment of ileitis

The best preventative option for ileitis depends on the specific farm

Prevention of ileitis

The indications are that nearly all pig populations are susceptible to Lawsonia Intracellularis

Prevalence of ileitis

The ban on antimicrobial growth promoters in the EU affected the kinetics of the infection in different pig diseases

Potential impact of the reduction of antibiotics

Economic impact results mostly from productivity losses caused by the disease