Detection of Lawsonia intracellularis in faeces of swine from the main producing regions in Brazil.

Swine proliferative enteropathy is an enteric disease caused by Lawsonia intracellularis which affects animals between 6 and 20 weeks of age, causing diarrhea, anorexia, and poor growth. The presence of L. intracellularis was evaluated in the faecal samples of 636 swine from 75 randomly chosen herds in the main swine-producing regions of Brazil. The pathogen was detected by the polymerase chain reaction method (PCR) using L. intracellularis specific primers. A 319-bp DNA fragment specific for L. intracellularis was produced on amplification of DNA from the faeces of pigs with proliferative enteropathy. Equal amounts of DNA extracted from the faeces of animals from the same herd were pooled together and, once L. intracellularis was detected, the faecal material of each animal was analyzed separately. The incidence of L. intracellularis was 33.4% in the state of Santa Catarina, 29.4% in Paraná, 26.3% in Minas Gerais, 16.7% in Mato Grosso, and 7.1% in São Paulo. The presence of the pathogenic agent was detected in samples from 15 farms, representing a total incidence of 20%. Although 46 animals (7.2%) were shown to be infected, 11% did not present any symptoms of swine proliferative enteropathy. The use of PCR allowed the detection of L. intracellularis in swine farms and the evaluation of the incidence of proliferative enteropathy in different regions of Brazil.