Lawsonia intracellularis in rodents from pig farms with the occurrence of porcine proliferative enteropathy

Aim:  Lawsonia intracellularis is an obligate intracellular bacterium causing proliferative enteropathy in certain species of domestic, laboratory and captive animals. The aim of our study was to detect L. intracellularis in free-living rodents from pig farms in the Czech Republic.
Methods and Results:  Lawsonia intracellularis was demonstrated, using nested polymerase chain reaction, in the intestinal mucous membranes of 107 (36%) out of 296 small terrestrial mammals collected. In rodents, the bacterium was detected in 91 of 213 house mice, one of six brown rats, eight of 51 striped field mice, three of 12 yellow-necked mice and three of nine common voles. Moreover, one of one tested lesser white-toothed shrew (Insectivora) was positive. In 17 out of 69 (25%) rodents tested, serum IgG antibodies against L. intracellularis were detected using an indirect immunofluorescence antibody test. All seropositive animals were house mice.
Conclusions:  Free-living rodents may be serving as host or reservoir species and may be playing a role in the spread of L. intracellularis both within pig farms and in its transmission between farms and into the natural environment.
Significance and Impact of the Study:  This is the first detection of L. intracellularis in free-living small mammalian terrestrial species.