Proliferative Enteropathy Involving Lawsonia intracellularis Infection in Rabbits (Oryctlagus cuniculus)

Abstract

ABSTRACT. Five rabbits suffering from diarrhea were diagnosed with proliferative enteropathy (PE). Histopathology revealed a thickened mucosa consisting of hyperplastic intestinal epithelium and infiltration of inflammatory cells mainly consisted of macrophages. In the affected epithelial cytoplasm, numerous curved bacillus-like organisms were observed in the Warthin-Starry silver stain and electron microscopy observation. In polymerase chain reactions, Lawsonia intracellularis-specific DNA fragment were amplified from affected ileal tissue extracted DNA in each case and present 5 cases were confirmed to be L. intracellularis infection. Serum collected from the affected rabbit was immunohistochemically reactive with L. intracellularis in tissue sections from pigs with porcine proliferative enteropathy, as well as with tissue sections from the five affected rabbits. [5,7]. L. intracellularis infection is known to cause proliferative enteropathy (PE) that is characterized by intestinal mucosa thickened with gross material and histopathological evidence of hyperplastic mucosal epithelium [7].Due to its appearance as an intracellular parasite, L. intracellularis was previously referred to as an Intracellular Campylobacter Like Organisms (ICLOs) [7,10,11]. ICLOs infections in pig, hamster, and rabbit have since been confirmed to be L. intracellularis infection [3,7]. In Japan, ICLO infections in rabbit have been reported [12], but until now, no evidence of the presence of L. intracellularis in infected rabbit has been presented. Here we report five field cases of rabbits diagnosed with PE in which L. intracellularis infection is confirmed by amplification of L. intracellularis DNA using polymerase chain reaction (PCR). We also demonstrate the successful use of serum obtained from affected rabbit for the immunohistochemical (IHC) detection of L. intracellularis.Four adult rabbits (cases 1-4) housed together in the one field at a wildlife park in the eastern area of mainland Japan developed diarrhea simultaneously. These rabbits were destroyed humanely, and preserved in formalin, and then sent to our laboratory. Case 5 was a 3-month-old female rabbit, housed separately in a conventional cage, which suffered from diarrhea and body weight loss. This rabbit was destroyed humanely and autopsied in our laboratory.Alimentary tract tissue samples, including duodenum, jejunum, ileum, cecum, and colon were collected and routinely fixed (or re-fixed) in 15% neutral-buffered formalin. Samples embedded in paraffin were then cut into 4 mm sections that were stained with hematoxylin and eosin (H&E). Selected sections were also stained with Gram's (MacCallum-Goodpasture method), Warthin-Starry silver (W-S), and Ziehl-Neelsen (modified Fite method) stains. For ultrastructual study, formalin fixed tissues were cut into 1 mm cubes, fixed in 2.66% glutaraldehyde for 2 hr, post-fixed in 1% osmium tetroxide and then embedded in epoxy resin. Ultra-thin sections, stained doubly with uranyl acetate and lead citrate, were examined using a tra...

Biology and Diseases of Rabbits

“…Diarrhea, depression, and dehydration that resolved over the course of 1-2 weeks were reported in 5-to 8-week-old New Zealand White (NZW) rabbits (Hotchkiss et al, 1996). Diarrhea and weight loss were reported in a 3-month-old rabbit (Horiuchi et al, 2008). An outbreak of diarrhea with high (70%) mortality was reported in 2-to 4-month-old NZW rabbits with proliferative enterocolitis associated with L. intracellularis and EPEC (Schauer et al, 1998).…”

“…These assays can be used for ante mortem diagnosis of proliferative enteropathy in pigs (Pedersen et al, 2010). PCR primers used to diagnose Lawsonia in other animals species have been used in rabbit cases (Cooper et al, 1997b;Duhamel et al, 1998;Fox et al, 1994;Horiuchi et al, 2008;Hotchkiss et al, 1996;Jones et al, 1993). Other diagnostic methods include enzyme-linked immunosorbent assay (ELISA) using synthetic peptides of LsaA and immunomagnetic separation using anti-LsaA antibody to capture L. intracellularis in fecal samples followed by detection with ATP bioluminescence (Watarai et al, 2004(Watarai et al, , 2005.…”

Prevalence of Lawsonia intracellularis, Salmonella spp. and Eimeria spp. in Healthy and Diarrheic Pet Rabbits

“…, Dong Hyeok KIM 1) , Jin Ju LEE 1) , Dae Geun KIM 1) , Sang Hun KIM 2) , WonGi MIN 1) , Hong Hee CHANG 1) , Man Hee RHEE 3) and Suk KIM 1) * 1) Institute of Agriculture and Life Science, Gyeongsang National University, Jinju 660-701, Korea 2) Gastrointestinal disease caused by pathogenic microorganisms is a cause of high morbidity and mortality in pet rabbits. The most common pathogens associated with gastrointestinal disease include L. intracellularis, E. coli, Salmonella spp., Eimeria spp.…”

“…On the other hand, diarrheic adult and old rabbits showed higher susceptible to Eimeria than young rabbits (P<0.05; ChiSqaure Test, SPSS ver 10), suggesting that the age of rabbit seems a factor of gastrointestinal disorder by Eimeria. Recently, rabbit infections with L. intracellularis were reported [3,4], but the prevalence of L. intracellularis has not been described in rabbits. Considering that Salmonella intermittent shedding is observed in animal salmonellosis [7], the proportion of pet rabbits with Salmonella may be higher than 9.4% of this study.…”

Effector prediction in host-pathogen interaction based on a Markov model of a ubiquitous EPIYA motif

“…(2) Lawsonia intracellularis: Lawsonia intracellularis is an obligate intracellular bacterial pathogen, which infects a wide range of animals, mainly pigs, and causes proliferative enteropathy - a type of contagious diseases [30,31] . Its symptoms are acute, including diarrhea, loss of appetite and stunting.…”