[Diagnosis of Lawsonia intracellularis using the polymerase chain reaction (PCR) in pigs with and without diarrhea and other animal species].

The study examines the prevalence of Lawsonia (L.) intracellularis, a bacterium usually causing intestinal disease in swine, in various animal species in Germany, including pigs without diarrhea, by using the polymerase chain reaction (PCR) method, a popular technique for amplifying DNA.

Research Objectives and Methodology

• The research aimed to determine the spread of the obligately intracellular bacterium Lawsonia intracellularis, which typically leads to proliferative enteropathy (a disease characterized by thickening of the intestinal lining) in swine, among various animal species, both domestic and wild, in Germany.
• For this purpose, researchers used the polymerase chain reaction (PCR) technique, a method commonly employed in molecular biology to generate multiple copies of a DNA sequence. It allowed the researchers to detect the presence of L. intracellularis DNA in the fecal samples collected.
• DNA was extracted from the feces using high concentrations of chaotropic salt and diatomaceous earth, and the PCR was performed using primers flanking a particular fragment of L. intracellularis DNA.

Sample Groups and Findings

• The fecal samples were collected from pig herds both showing and not showing symptoms of diarrhea. The sample groups also extended to diarrheic foals, dogs, cats, calves, hedgehogs, seals, and a giraffe.
• L. intracellularis was detected in the samples from 21 pig herds (30%) without symptoms of diarrhea and 224 herds (34.6%) with diarrhea symptoms.
• The bacteria were also found in feces from dogs, calves, hedgehogs, and the giraffe, while other species tested negative.

Significance of the Research

• This study highlights the spread and prevalence of L. intracellularis in various animal species and their specific herds. It emphasizes how bacteria commonly associated with one species (i.e., pigs) can equally affect other species.
• The use of PCR in diagnosing the presence of these bacteria has proven its effectiveness as a diagnostic tool and forms a fundamental part of veterinary diagnostic strategies.