Isolation of a Mycobacterium microti-like organism from a rock hyrax (Procavia capensis) in a Canadian zoo

A Mycobacterium tuberculosis complex organism was isolated from a zoo resident rock hyrax (Procavia capensis) imported into Canada from South Africa. The strain was identified biochemically as Mycobacterium microti. The spoligotype pattern obtained for this isolate was found to be rare. This represents the first report of isolation and spoligotyping of M. microti in North America.     

Growth and age determination in the hyrax Procavia capensis

Growth and age determination were studied in known age captive hyrax by measuring the animals monthly for three years and killing groups at ages 12,24 and 36 months. Ten body measurements and five skull measurements were used as ageing criteria using multiple regression and a predictive equation. Age (months) = 0,0593 Length + 0,0444 Girth + 0,01117 Headlength - 20,652 was developed for both sexes. Tooth eruption and wear, dental annulli and eyelenses were also investigated and an ageing schedule was developed using tooth eruption and wear. Cementum annulli were shown to be a valid means of ageing up to 36 months and probably up to at least eight years. Eyelenses are not an effective ageing method. Growth in the hyrax is slow and Von Bertalanffy growth coefficients are similar to those in the elephant.     

Surgical castration and the effect on aggression in rock hyrax (Procavia capensis).

Lincoln Park Zoo acquired five intact, male rock hyraxes (Procavia capensis) from three separate institutions to exhibit as a group. The animals were of varying ages at the time of acquisition. During quarantine, all five were surgically castrated via a midline laparotomy technique in an attempt to reduce expected aggression within the group. Recommendations for successful castration, based on these five procedures, include performing the procedure on sexually immature hyraxes or sexually inactive adults, the use of a second surgeon during the procedure, and the use of stainless steel surgical clips for ligation of vessels and spermatic cord. Although combinations of the castrated animals coexisted for longer periods than those documented for other nonrelated male groups, aggression was significant and resulted in the death of one individual. Ultimately, all animals were housed individually.     

Disseminated tuberculosis caused by Mycobacterium avium in a cat

A 5-year-old neutered male Siamese cat was examined by a veterinarian because of a recent decrease in appetite and a large lymph node in the left mandibular area. Clinical findings included fever, icterus, leukopenia, and progressive anemia. Despite various treatments, the cat died approximately 3 weeks after initial examination. The main necropsy findings included necrotizing and granulomatous lymphadenitis of the left mandibular lymph node, multifocal necrotizing hepatitis, and interstitial pneumonia. Acid-fast bacilli were detected in lesions of the mandibular lymph node, liver, lung, spleen, and bone marrow. Mycobacterium avium was isolated from the liver. Avian tuberculosis in cats has been reported rarely.     

Pancreatic islet fibrosis in rock hyrax (Procavia capensis), Part 2: Pathology, immunohistochemistry, and electron microscopy.

Pancreatic islet fibrosis with varying degrees of islet cell hyperplasia or islet effacement was diagnosed histologically in 19 rock hyraxes (Procavia capensis) from seven zoological parks. Some, but not all, affected hyraxes were from a common lineage. The condition was associated with apparent hyperglycemia in seven and diabetes mellitus in two. Immunohistochemistry revealed hyperplasia of beta, alpha, and delta cells proportional to the degree of the fibrosis. Electron microscopy revealed collagen deposition and fibroplasia within and around the islets. Special stains and electron microscopy were negative for the presence of amyloid. Beta cell depletion was never identified. The condition has morphologic features that resemble islet fibrosis of human infants born to diabetic mothers.     

Relationship between heart rate and metabolism in the hyrax (Procavia Capensis) and guineapig (Cavia porcellus)

The relationship between heart rate and metabolism was investigated in the hyrax Procavia capensis and the guineapig Cavia porcellus. In both animals a positive linear relationship was found described by Vo₂(ml 0₂(g.h)-¹)=0,003157 (HR) + 0,3678 for the hyrax and Vo₂(ml 0₂(g.h)-¹)=0,00757 (HR) -0,4914 in the guineapig. The response to lowered ambient temperature differs between the species, the guineapig increases metabolic rate and maintains body temperature while the hyrax allows body temperature to drop while the increase in metabolic rate is relatively small. It is postulated that this response by the hyrax is an energy conserving strategy.     

Cutaneous lesion caused by Mycobacterium tuberculosis in a dog

A 5-month-old female mixed-breed dog was examined because of nonhealing wounds in the right submandibular region. Treatment with antibiotics and surgical excision was ineffective. Specimens of the right mandibular lymph node and surrounding tissues were submitted for bacteriologic culturing, and Mycobacterium tuberculosis was isolated. The dog was euthanatized. The risk of infection of human beings who associate with dogs that have cutaneous wounds caused by mycobacteria is unknown.     

Naturally occurring tuberculosis caused by Mycobacterium bovis in brushtail possums (Trichosurus vulpecula): II. Pathology

The gross and microscopic lesions due to Mycobacterium bovis infection are described in 73 brushtail possums (Trichosurus vulpeculu) from population studies and from 11 terminally ill possums. Subcutaneous lesions were suppurative in nature, often discharging through sinuses to the exterior. Histologically, the smallest lesions comprised focal aggregations of macrophages with angulated cytoplasmic boundaries occasionally containing acid-fast organisms. Larger lesions were pyogranulomatous, with extensive necrosis, caseation and large numbers of intra- and extra-cellular acid-fast organisms. Few multinucleate giant cells were seen and fibroplasia was rare. Mineralisation was recorded in tuberculous lymph nodes from only two possums. Histological evidence of haematogenous and lymphatic spread was seen in some cases.     

Antibody responses in New World camelids with tuberculosis caused by Mycobacterium microti

Antibody responses in New World camelids (NWC) infected with Mycobacterium microti were studied by two serological methods, multiantigen print immunoassay (MAPIA) and lateral-flow-based rapid test (RT). Serum samples were collected during 2004-2006 from 87 animals including 1 alpaca and 7 llamas with confirmed or suspected M. microti infection, 33 potentially exposed but clinically healthy animals from known infected herds, and 46 control NWC from herds where infection had not been previously diagnosed. The serological assays correctly identified infection status in 97% (MAPIA) or 87% (RT) cases. In three llamas with confirmed M. microti infection and one llama with gross pathology suggestive of disease, for which multiple serum samples collected over time were available, the antibody-based tests showed positive results 1-2 years prior to the onset of clinical signs or being found dead. In MAPIA, MPB83 protein was identified to be an immunodominant serological target antigen recognized in NWC infected with M. microti. With the limited number of animals tested in this study, the serological assays demonstrated the potential for convenient, rapid, and accurate diagnosis of M. microti infection in live llamas and alpacas.     

An outbreak of tuberculosis by Mycobacterium bovis in coatis (Nasua nasua)

Mycobacterium tuberculosis complex, which includes Mycobacterium bovis, infrequently causes severe or lethal disease in captive wildlife populations. A dead coati from a wildlife triage center showing pulmonary lesions compatible with tuberculosis had raised suspicion of a potential disease caused by mycobacteria species and was further investigated. Four native coatis (Nasua nasua) with suspected mycobacterial infection were sedated, and bronchoalveolar lavages and tuberculin skin tests (TSTs) were performed. All animals tested positive upon TST. Mycobacterial culturing, Ziehl-Neelsen staining, and genetic testing were performed on postmortem samples and the etiologic agent was identified as M. bovis. Molecular genetic identification using a polymerase chain reaction panel was crucial to achieving a definitive diagnosis.     

Reproduction in the Rock Hyrax (Procavia Capensis)

Irradiation has adverse effects on reproductive aspects such as spermatogenic cell population and cell malformation, leading to reduced sperm count and non-viable spermatozoa. This has overshadowed possible effects of radiation exposure on biochemical environment throughout the epididymis and the viability of spermatozoa that appeared morphologically normal. The effects of radiation exposure on sperm quality were evaluated through mating trials and assessment of the cauda epididymal sperm motility. Sprague Dawley rats with body mass of 300–400 g were selected at random. Two experimental groups received acute ⁶°Co γ-radiation doses of 3.5 and 6.0 Gy, respectively. Data were collected 2, 7, 14, 21, 28 and 35 days post-irradiation. Each male was housed with a non-irradiated super-ovulated female during mating trials. Cauda epididymal sperm motility was assessed with the CASMA. Hormone analyses were carried through chemiluminescence diagnostic tests to determine the endocrine status. Results suggest that irradiation causes an overproduction of estrogens, which suppresses the hypothalamic-pituitary axis and inhibits LH and FSH secretions. Both LH and FSH deficiencies have negative effects on the testicular index and local reproductive hormones. Elevated estrogen levels influenced the epididymal internal milieu negatively, resulting in rigid, flagella bending sperm tail, impaired progressive movement of the spermatozoa and hence infertility     

Disseminated Mycobacterium celatum (type 3) infection in a domestic ferret (Mustela putorius furo)

A 4-year-old male ferret (Mustela putoriusfuro) had a 6-month history of weight loss and gradual development of depression and coughing. Necropsy findings included pale gray tissue around the distal trachea, multiple nodules in the lungs, a single nodule in the stomach wall, gray foci in the liver, and enlarged lymph nodes. Histologic examination revealed multifocal to coalescing granulomatous inflammation in the trachea, lungs, stomach, liver, and lymph nodes, with acid-fast bacteria in epithelioid cells and macrophages. The acid-fast bacteria were identified as Mycobacterium celatum (type 3) using DNA sequence analysis of the 16S ribosomal DNA gene. M. celatum is a recently described mycobacterium isolated mainly from immunocompromised humans. This is the first report of M. celatum infection in an animal.     

Naturally occurring tuberculosis caused by Mycobacterium bovis in brushtail possums (Trichosurus vulpecula): III. Routes of infection and excretion

Mycobacterium bovis was cultured from nine of 25 (36%) tracheal washings but not from any of 38 urine and 38 faecal samples from tuberculous possums cross-sectionally sampled from the wild. One of three tracheal washings, one of three urine samples and one of three faecal samples from terminally ill possums were culture-positive. The respiratory route is implicated as the major route of excretion of Mycobacterium bovis from naturally infected possums in horizontal transmission. Tuberculosis was observed in two young possums and was evidence of probable pseudo-vertical transmission via the respiratory route or ingestion of milk. Discharging fistulae were present in 22 of 71 (31%) cross-sectionally sampled tuberculous possums and were associated with relatively advanced disease. Although the frequent involvement of superficial lymphocentres in early stage disease could not be explained satisfactorily, the respiratory route was implicated as the main route of infection from indirect evidence.     

The distribution of gross lesions of tuberculosis caused by Mycobacterium bovis in feral ferrets (Mustela furo) from Otago, New Zealand

The distribution of gross lesions of Mycobacterium bovis was examined in 94 tuberculous feral ferrets (Mustela furo) collected from 1992 to 1995 from areas of Otago endemic for bovine tuberculosis. Overall, 56.4% of tuberculous ferrets had single-site lesions, 24.5% had multiple infections and 19.1% had generalised infections. The mesenteric lymph node was the most common site of infection (34.5% of all lesions), with the retropharyngeal (17%) and the prescapular lymph nodes (16.4%) also frequently infected. Only 2.9% of lesions involved the respiratory tract. Of single-site lesions, 60.4% were in the mesenteric lymph node. The high proportion of lesions in the alimentary tract suggests that the ingestion of infectious material, possibly carrion or prey, is an important source of infection. Peripheral lymph nodes contributed to 24.5% of all infections, suggesting that within species transmission by social contact such as fighting and mating also occurs. Open and respiratory lesions were found in 11.7% of tuberculous ferrets, which suggests that ferrets are potentially infectious and therefore may be involved in the transmission of bovine tuberculosis to domestic stock and other mammals. The distribution of gross M. bovis lesions in ferrets is compared to those observed in possums (Trichosurus vulpecula) and badgers (Meles meles).     

Naturally occurring tuberculosis caused by Mycobacterium bovis in brushtail possums (Trichosurus vulpecula): I. An epidemiological analysis of lesion distribution

Gross and microscopic lesion distributions and culture test results are described for 73 tuberculous possums recovered from a series of cross-sectional studies involving about 500 detailed necropsies. Pathological findings from 11 terminally ill tuberculous possums are also described. Quantitative epidemiological techniques were applied to lesion site data to assess factors influencing the pathogenesis of the disease. In possums with gross lesions, the number of distinct body sites affected varied from one to 10 per animal, with a mean of 4.6. The total number of gross plus microscopic lesions varied from one to 28 per animal with a mean of 11.6, indicating that the degree of generalisation of disease was much greater than appeared grossly. Of 119 possums with no gross lesions which were subjected to additional examinations, tuberculosis was diagnosed in ten (8.4%) by histology or culture of pooled lymph nodes. Among cross-sectional sample tuberculous possums, lesions were found in lungs in 85%, in axillary lymphocentres in 85%, in inguinal lymphocentres in 69%, and in either axillary or inguinal lymphocentres in 95%, indicating that the disease spread rapidly to multiple body sites. More males than females were infected (relative risk = 1.78). When cross-sectionally sampled infected and non-infected possums were compared, no significant associations were found between the presence/absence of disease and either age or indices of body condition, although debility was seen in animals with terminal illness.     

Disseminated panniculitis in a bottlenose dolphin (Tursiops truncatus) due to Mycobacterium chelonae infection

A 14-year-old female bottlenose dolphin was diagnosed with mycobacterial panniculitis based on punch biopsy specimens. The necropsy revealed numerous pyogranulomas in the blubber, as well as marked acute multifocal necrosuppurative pneumonia and lymphadenitis. In addition, the animal had marked scoliosis, which had first been noted clinically in the dolphin at about 1 mo of age. The animal had been treated with low-dose dexamethasone for approximately the last 19 mo to reduce perceived discomfort from spondyloarthritis and with the progestational agent altrogenest for approximately 8 yr to prevent pregnancy. Acid-fast positive bacilli were detected in the dermis but not in lung or lymph nodes. Mycobacterium chelonae was isolated from pooled skin, lung, and peripheral lymph-node tissue. Mycobacterial infection may be considered as a differential diagnosis in bottlenose dolphins with generalized cutaneous inflammation, particularly if chronic steroid and progesterone treatments were administered, both of which may have an immunomodulatory effect.     

Pancreatic islet fibrosis in rock hyraxes (Procavia capensis), Part 1: Case histories, clinical pathology, and epizootiology.

Two adult female rock hyraxes (Procavia capensis) at the Dallas Zoo were confirmed with spontaneous diabetes mellitus from 1997-2000, whereas a third animal with a similar clinical presentation never became hyperglycemic. The pancreas in all three animals showed pancreatic islet fibrosis (PIF). Retrospective examination of medical records for rock hyraxes acquired by this collection or born into it from 1991-2002 identified eight more animals affected with PIE All affected animals, including three males and eight females, were 1-7 yr of age and presented either with vague clinical signs of soft feces and rough hair coat or were acutely moribund or dead. Clinical pathology data was available for seven of the animals before onset of overt clinical signs and revealed inappropriate hyperglycemia in six, as well as elevated serum concentrations of creatine phosphokinase, amylase, and lipase in all seven animals. Pedigree evaluation did not support a familial pattern for PIE Review of the histopathology findings from nine other zoologic collections with rock hyrax deaths during the study period identified six institutions with 12 additional cases genetically unrelated to the incident collection. Histopathology and viral serology did not support an infectious cause. Analysis of serum anti-islet and anti-insulin antibodies did not suggest autoimmune disease, and none of the animals had known exposure to toxic substances. Limited nutritional analyses did not support a nutritional basis for the condition, and the cause for PIF remains unknown.     

Disseminated Mycobacterium avium infection in a cat

A domestic shorthair cat was presented for lethargy and ataxia. Clinical findings included an abdominal mass, lumbosacral pain, ataxia. Aspirates from the liver and lymph nodes revealed intracellular, negative-staining rods. Treatment for presumptive mycobacterium infection was unsuccessful and the cat was euthanized. Disseminated Mycobacterium avium was confirmed on culture.