title: Species-specificity of equine and porcine Lawsonia intracellularis isolates in laboratory animals.
abstract: Lawsonia intracellularis infection causes proliferative enteropathy (PE) in many mammalian species, with porcine and equine proliferative enteropathy (PPE and EPE) known worldwide. Hamsters are a well-published animal model for PPE infection studies in pigs. There is no laboratory animal model for EPE infection studies and it is not known whether there is species-specificity for equine or porcine isolates of L. intracellularis in animal models. The objective of this study was to determine whether it is possible to generate typical EPE lesions in hamsters after inoculation with an equine strain of L. intracellularis (EPE strain) and whether it is comparatively possible to generate PPE lesions in rabbits after inoculation with a porcine strain of L. intracellularis (PPE strain). In 2 separate trials, 4-week-old and 3-week-old weanling golden Syrian hamsters were challenged with EPE strains and compared to uninfected (both trials) and PPE-infected controls (Trial 2 only). Concurrently, 6 female New Zealand white juvenile rabbits were infected with PPE strain and observed concomitantly to 8 similar rabbits infected with EPE strain for a different experiment. Hamsters and rabbits were observed for 21 to 24 days post-infection (DPI), depending on the experiment. Neither infected species developed clinical signs. The presence of disease was assessed with diagnostic techniques classically used for pigs and horses: immune-peroxidase monolayer assay on sera; quantitative polymerase chain reaction (qPCR) detection of molecular DNA in feces; and hematoxylin and eosin (H&E) stain and immunohistochemistry (IHC) on intestinal tissues. Our results showed that EPE-challenged hamsters do not develop infection when compared with PPE controls (IHC, P = 0.009; qPCR, P = 0.0003). Conversely, PPE-challenged rabbits do not develop typical intestinal lesions in comparison to EPE-challenged rabbits, with serological response at 14 DPI being significantly lower (P = 0.0023). In conclusion, PPE and EPE strains appear to have different host-specificities for hamsters and rabbits, respectively.
authors.affiliation: Department of Veterinary Biomedical Sciences (Sampieri, Antonopoulos, Ball, Dowling, Hamilton) and Department of Veterinary Pathology (Allen), Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B4; Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, Minnesota 55108, USA (Vannucci, Gebhart); Department of Veterinary Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, California 95616, USA (Pusterla); Canadian Light Source, Saskatoon, Saskatchewan (Thompson).
authors.forename: Francesca
authors.initials: F
authors.lastname: Sampieri
authors.forename: Fabio A
authors.initials: FA
authors.lastname: Vannucci
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Allen
authors.forename: Nicola
authors.initials: N
authors.lastname: Pusterla
authors.forename: Aphroditi J
authors.initials: AJ
authors.lastname: Antonopoulos
authors.forename: Katherine R
authors.initials: KR
authors.lastname: Ball
authors.forename: Julie
authors.initials: J
authors.lastname: Thompson
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Dowling
authors.forename: Don L
authors.initials: DL
authors.lastname: Hamilton
authors.forename: Connie J
authors.initials: CJ
authors.lastname: Gebhart
mesh_terms: D000818:Animals; D006224:Cricetinae; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D045824:Desulfovibrionaceae Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D004195:Disease Models, Animal; D005243:Feces / Q000382:microbiology; D005260:Female; D006734:Horse Diseases / Q000276:immunology / Q000382:microbiology*; D006736:Horses; D007150:Immunohistochemistry / Q000662:veterinary; D007410:Intestinal Diseases / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D020639:Lawsonia Bacteria / Q000235:genetics / Q000302:isolation & purification*; D008647:Mesocricetus; D016133:Polymerase Chain Reaction / Q000662:veterinary; D011817:Rabbits; D011897:Random Allocation; D013045:Species Specificity; D013047:Specific Pathogen-Free Organisms; D018709:Statistics, Nonparametric; D013552:Swine; D013553:Swine Diseases / Q000276:immunology / Q000382:microbiology*
chemical_list: D004269:DNA, Bacterial