Hepatic yersiniosis in a cougar (Felis concolor)

Outbreak in African lions of Yersinia pseudotuberculosis infection, with aberrant bacterial morphology

A concurrent outbreak of infection with Yersinia pseudotuberculosis occurred in adult captive African lions (Panthera leo). Two 17-y-old male lions and one 14-y-old female lion developed respiratory distress, lethargy, ataxia, and hyporexia. Within 3-5 d of the onset of clinical signs, one male and the female lion died and were submitted for postmortem examination. Macroscopically, the liver and spleen had multifocal-to-coalescing, semi-firm, pale-tan nodules throughout the parenchyma. The lungs were non-collapsed and marked by petechiae. Histologic examination identified lytic, necrosuppurative foci in the liver, spleen, lungs, and kidney, with abundant intralesional gram-negative coccobacilli in the male lion. Similar findings were seen in the female lion in the liver, spleen, kidney, and mesenteric lymph node; however, the intralesional bacterial colonies were more pleomorphic, comprising rod and filamentous morphologies. Aerobic bacterial culture of the liver, spleen, and lung revealed Y. pseudotuberculosis growth. The source of infection is unknown, and an epidemiologic study was performed. Sources to be considered are from the predation of rodent and/or bird reservoirs, or contaminated soil or water. Mortality associated with Y. pseudotuberculosis has been described in an African lion cub, however, to our knowledge, Y. pseudotuberculosis has not been reported in adult African lions, and this is only the second report of Y. pseudotuberculosis with aberrant bacterial morphology observed histologically.

Comparison of pathological changes in the study of dogs affected by parvoviral enteritis and intestinal yersiniosis

Aim of the study: to examine the pathological changes in dogs that died due to confirmed intestinal yersiniosis and parvoviral enteritis and establish trends for characteristic organ lesions for both diseases in comparison, then evaluate our findings with the existing published material of sufficient evidence quality regarding differential postmortem diagnosis of spontaneous intestinal yersiniosis and parvoviral enteritis in dogs. Materials and methods: the study examined the cases of 25 dogs from 2 month to 1.3 y.o. of various breed, gender that died due to either confirmed Canine parvoviral enteritis (CPV) infection or intestinal yersiniosis and subsequently divided into two groups based on their diagnosis. The definitive diagnosis has been confirmed by performing rapid ELISA diagnostics (SensPERT®, VetAll Laboratories, Kyunggi-Do, Korea) for CPV and serological tests for Y. enterocolitica sera AT were performed using yersiniosis antigens from the "Component set for serological diagnosis of animal yersiniosis" (Kharkiv, NSC IEKVM, TS 46.15.091-95) in accordance with the "Interim guidelines for the use of a set of components for serological diagnostics". A dilution of 1: 200 has been considered as the diagnostic titer. After the definitive diagnosis had been confirmed, the animals were divided into two groups, depending on diagnosis: CPV (n=14) or IY (n=11). The autopsies of twenty randomly (10 from each group) selected dog corpses have been conducted utilizing standard methodology. Results: according to the results of autopsy of dogs afflicted by CPV, the main pathological changes were found in the small intestine – catarrhal-desquamative inflammation (in 100 % of cases), serous-hemorrhagic mesenteric lymphadenitis (90 %) large intestine (70 %) in the stomach (60 %), in the liver (50 %), in other organs – less than 40 percent of cases and most notably caused lung damage (edema and local atelectasis) in 90 % of the animals in the study, which was not the case for intestinal yersiniosis with only 20 % incidence of lung damage. Conclusions: Spontaneous intestinal yersiniosis in dogs was pathologically manifested by pronounced catarrhal-desquamative processes mainly in the stomach and small intestine (70, 100 and 80 % of cases, respectively), inflammation of the mesenteric lymph nodes (90 %) and large intestine (80 %), dystrophy and congestive processes in the liver (80 %). Low incidence and type of lung damage (congestive hyperemia in 20 % of reviewed cases compared to 90 % of local atelectasis add edema in CPV group) was noteworthy. Cases of 25 animals that died due to either confirmed CPV or Y. enterocolitica infection were analyzed, and 20 animal corpses were autopsied during study. Dogs that died from intestinal yersiniosis had significantly higher frequency of pathological findings in kidney (200 %) and liver (60 %) in particular. Changes in stomach and large intestine were also more frequent. At the same time, we observed a lower frequency of pathological changes in spleen (33 % lower), heart (25 % lower) and the lowest frequency was in lungs (77 % lower) presented by edema and local atelectasis in animals afflicted by yersiniosis compared to CPV. Incidence and manifestation of pathological findings was mesenteric lymph nodes and abdominal cavity were similar, and could not be considered during posthumous diagnostics.

Yersiniosis due to infection by Yersinia pseudotuberculosis 4b in captive meerkats (Suricata suricatta) in Japan

Two meerkats ( Suricata suricatta) housed in the same zoological garden in Japan died due to Yersinia pseudotuberculosis serotype 4b infection. Gross and microscopic lesions included necrotizing enteritis and enlargement of the spleen and liver with multifocal necrosis. Inflammatory cells, primarily neutrophils, and nuclear debris were associated with clusters of Gram-negative bacilli. Additionally, there were aberrant organism forms that were larger than bacilli and appeared as basophilic globular bodies. Immunohistochemical examination showed that the bacilli and globular bodies were strongly positive for Y. pseudotuberculosis O4 antigen. The globular bodies were considered a shape-changed form of Y. pseudotuberculosis, and these morphologically abnormal bacteria could present a diagnostic challenge.

Hepatic yersiniosis caused by Yersinia enterocolitica 4:O3 in an adult dog

A 2-year-old Pekinese dog was diagnosed with hepatic yersiniosis. Grossly, white-to-yellow nodules consisting of degenerated inflammatory cells, cell debris, and bacterial clumps were scattered throughout the liver. Histopathologically, suppurative and necrotizing hepatitis was apparent. Yersinia enterocolitica biotype 4, serotype O3 (4:O3) was identified and confirmed in the liver immunohistochemically, using a monoclonal antibody. The virulence genes ystA and ail were detected, but the isolate was negative for autoagglutination and calcium-dependent growth. To confirm systemic yersiniosis in animals, it is imperative that the organism(s) be identified because the hepatic lesions are similar to those of Y. pseudotuberculosis and other diseases, including plague, which is also a zoonotic pathogen.

Fatal yersiniosis in farmed deer caused by Yersinia pseudotuberculosis serotype O:3 encoding a mannosyltransferase-like protein WbyK

Sudden death of 9 deer occurred in a large enclosed deer farm with approximately 400 heads of cervids. Fatal yersiniosis was diagnosed in 2 deer that were submitted for laboratory diagnosis. Histopathologically, the disease was characterized by multifocal pulmonary hemorrhage and mild interstitial pneumonia, marked diffuse cholangiohepatitis, minimal myocarditis with mild myocardial degeneration, and mild multifocal suppurative cystic colitis. Yersinia pseudotuberculosis was isolated from the lungs and colon of the affected animals. The isolates were PCR-positive for genes virF, inv, yopB, and yopH, which are essential for invasion and colonization of host intestine and lung. The isolates reacted with polyclonal antibodies against serotype O:3 antigen. The O-genotyping patterns of the isolates were identical with each other, but different from those of the 21 O-genotypes (or serotypes) reported previously. In addition to the O-antigen genes possessed by classical serotype O:3, a gene (wbyK) encoding a mannosyltransferase-like protein was detected in these isolates. The wbyK gene of the isolates showed 94% of DNA sequence homology with the wbyK gene harbored by Y. pseudotuberculosis O:1b. On the basis of pathology, bacteriology, and serology, the authors concluded that the acute deaths of these deer were caused by Y. pseudotuberculosis infection. Molecular characterization of the isolate revealed a genetic heterogeneity in the O-antigen gene cluster of Y. pseudotuberculosis serotype O:3.