Mixed mycobacterial infections in farmed sturgeons

Based on microbiological and histopathological examinations and DNA sequencing, several outbreaks of mycobacteriosis in the reared sturgeons, including Chinese sturgeon (Acipenser sinensis Gray) and Amur sturgeon (Acipenser schrencki), were identified during 2009 to 2010. Forty‐nine isolates of non‐tuberculous mycobacteria(NTM)were isolated from 19 diseased sturgeons. In total, seven species of Mycobacterium were identified, namely, Mycobacterium chelonae, Mycobacterium marinum, Mycobacterium gordonae, Mycobacterium fortuitum, Mycobacterium szulgai, Mycobacterium arupense and Mycobacterium porcinum. Among them, M. marinum was found to be more prevalent (89.5%) compared with the other mycobacterial species. When two molecular biological methods, PCR‐DGGE (denaturing gradient gel electrophoresis) analysis and rpoB gene library sequencing, were used to analyse the mycobacterial DNAs extracted from the diseased fish tissues, mixed infections of two or three mycobacterial species were found being the predominant infection form (94.7%) in sturgeon mycobacteriosis. M. marinum was the only one species that caused sturgeon mycobacteriosis alone. Virulence assay showed that M. marinum possessed stronger pathogenicity to zebrafish killing 100% of fish in 28 days at 10³ cfu/fish than the other species. These results suggested that M. marinum is the major pathogenic bacteria in sturgeon mycobacteriosis. To the best of our knowledge, this study is the first report on mycobacteriosis in farmed Chinese and Amur sturgeons as well as the first isolation of M. porcinum and M. arupense from fish.     

Characterization of Mycobacterium salmoniphilum as causal agent of mycobacteriosis in Atlantic salmon,Salmo salar L., from a freshwater recirculation system

Thirty Atlantic salmon, Salmo salar L., with low corporal condition relative to other fish present in the culture system, were sampled from a freshwater recirculation pisciculture located in Chile. The most characteristic signs and lesions were cachexia and presence of multiple greyish‐white granulomas within internal organs. The external and internal lesions, along with the microscopic, histologic and biochemical findings, were consistent with mycobacteriosis. The identification of Mycobacterium salmoniphilum as the causal agent of the lesions was possible through the use of molecular analyses. This study represents the first report of Mycobacterium salmoniphilum in a freshwater recirculation system and the first case of fish mycobacteriosis described in Chile.     

Genital mycobacteriosis caused by Mycobacterium marinum detected in two captive sharks by peptide nucleic acid–fluorescence in situ hybridization

Mycobacterium marinum is a prevalent nontuberculous mycobacterium (NTM)-infecting teleosts. Conversely, little is known about mycobacteriosis in elasmobranchs, and M. marinum infection has never been reported from the subclass. This study investigated the histopathological characteristics and localization of this mycobacterium through molecular analysis of two captive sharks, a scalloped hammerhead Sphyrna lewini and a Japanese bullhead shark Heterodontus japonicus, exhibited in the same aquarium tank. We detected genital mycobacteriosis caused by M. marinum infection using molecular analyses, including polymerase chain reaction (PCR) and DNA sequencing targeting the 60 kDa heat-shock protein gene (hsp65), and peptide nucleic acid–fluorescence in situ hybridization (PNA-FISH) targeting the 16S rRNA gene. Both sharks showed granulomas in connective tissues of the gonads without central necrosis or surrounding fibrous capsules, which is unlike the typical mycobacterial granulomas seen in teleosts. This study reveals that elasmobranchs can be aquatic hosts of M. marinum. Because M. marinum is a representative waterborne NTM and a potential zoonotic agent, cautious and intensive research is needed to overcome a lack of data on the relationship between NTM and the aquatic environment in association with this subclass of Chondrichthyes.     

Disseminated Mycobacterium avium complex infection in a cat: presumptive diagnosis by blood smear examination

Disseminated mycobacteriosis was diagnosed in a 4-year-old, castrated male Domestic Shorthair cat following the observation of one to three retractile, non-staining bacilli in neutrophils and monocytes on a Wright-Leishman-stained blood smear Organisms were bright red following acid-fast staining by Kinyoun's technique. The cat had a history of progressive weight loss, anemia, fever, and sporadic vomiting after eating. In addition to blood smears, mycobacteria also were observed in bone marrow aspirates. During necropsy, multiple small white nodules were observed in the spleen and liver. An enlarged sternal lymph node and ascites also were present. In histologic sections, mycobacteria were observed in granulomas within the lungs, liver, spleen, colon, mesenteric and sternal lymph nodes, omentum, and kidney. Mycobacterium avium complex was isolated from cultures of liver, spleen, lung, and kidney. Occult feline leukemia virus infection, detected by immunofluorescent testing of bone marrow aspirates, may have predisposed this cat to bacterial infection. The serum ELISA test for group-specific feline leukemia virus antigen was negative.     

Massive envenomation by Vespula spp. in two dogs.

Two dogs, a 5 year old golden retriever and a 5 year old yellow Labrador, were stung by numerous yellow jackets (Vespula sup.). Both dogs exhibited signs consistent with direct toxic effect of the wasp venom. The laborador was more severely affected, and was euthanized less than 24 hours after after admission. On postmorten, changes were seen that were consistent with anaphylaxis and disseminated intravascular coagulation. The golden retriever, although exhibiting respiratory distress, prolongation of coagualtion, and increased liver enzymes, eventually made a full recovery.     

Parasitemia in a neonatal bison calf

A 3-day old female bison calf (Bison bison) was presented in lateral recumbency to the Université de Montréal Veterinary Teaching Hospital. The animal was severely depressed and dehydrated (10%) and died a few hours after admission. Prior to death, blood samples were obtained for CBC, clinical chemistry, and serology tests. Abnormal CBC findings included thrombocytopenia, lymphocytosis, mild monocytosis, and a toxic left shift. Abnormal serum clinical chemistry findings included marked azotemia, hyperphosphatemia, hypernatremia, hyperalbuminemia, hypoglobulinemia, and low gamma-glutamyltransferase activity. Serologic test results for bovine leukosis virus and bovine viral diarrhea virus were negative. Blood smear examination revealed numerous elongated organisms that were tapered at both ends and characterized by an undulating membrane and a long flagellum. The organisms ranged in length from 35 to 40 micro meter, excluding the flagellum, and were identified as Trypanosoma theileri. Postmortem examination revealed that the animal suffered from concurrent mycotic abomasitis and colisepticemia.     

Comparison of quantitative immunoturbidimetric and semiquantitative latex‐agglutination assays for D‐dimer measurement in canine plasma

Background: D‐dimer measurement in dogs is considered the most reliable test for detecting disseminated intravascular coagulation or thromboembolism. Objectives: The purposes of this study were to compare 2 D‐dimer assays, a quantitative immunoturbidimetric and a semiquantitative latex agglutination assay, and to assess the effect of hemolysis and storage conditions on D‐dimer concentration using the quantitative assay. Methods: The immunoturbidimetric assay was validated using canine citrated plasma samples containing different concentrations of D‐dimer. The effect of storage at various temperatures and times was assessed. Hemolysis was produced by adding lysed RBCs to the samples for a final hemoglobin concentration of 0.35 g/dL. Results: For clinically relevant values (>250 μg/L), intra‐assay and interassay coefficients of variation were 6.8% and 7.2%. The assay was linear (r²=1.00), and the tests had good agreement (κ=0.685, P<.001). Storage at 4 °C and ?20 °C and hemolysis had no significant effect on D‐dimer concentrations. In hemolyzed samples stored at room temperature for ≥48 hours, fine clots were noted and often resulted in falsely increased D‐dimer concentrations. Conclusions: Our findings suggest that the immunoturbidimetric assay validated in this study is reliable and accurate for the measurement of D‐dimer in canine plasma. Samples can be stored for up to 1 month at ?20 °C and moderate hemolysis does not significantly affect the D‐dimer concentration in frozen or refrigerated samples.     

Resolution of severe thrombocytopenia in two standard Poodles with surgical correction of splenic torsion

Objective: To describe the diagnosis and treatment of 2 cases of severe thrombocytopenia associated with splenic torsion and to discuss the pathophysiologic mechanisms underlying the thrombocytopenia. Summary: We report 2 cases of severe thrombocytopenia associated with splenic torsion. Each dog presented with non‐specific clinical signs, radiographic evidence of an intra‐abdominal mass, and platelet counts of less than 25,000 platelets/μL. The diagnosis of splenic torsion was made with abdominal ultrasonography and was confirmed during exploratory laparotomy. Both dogs recovered rapidly following splenectomy. The cause of thrombocytopenia associated with splenic torsion is not fully elucidated, but may be because of either platelet sequestration within the torsed spleen, platelet consumption in disseminated intravascular coagulation, or a combination of both. New information provided: This report provides previously unreported evidence that the degree of thrombocytopenia associated with splenic torsion may be of a severity at which primary hemostasis is compromised, and resolution of thrombocytopenia occurs after splenectomy.