Mastitis caused by Mycobacterium kansasii infection in a dog

A 2‐year, 7‐month‐old female Chihuahua was admitted for a mammary mass measuring one cm in diameter. The dog had a history of demodicosis for 4 months and showed signs of pseudopregnancy at the time of the visit. Cytologic examination of an aspirate of the mass revealed a large number of macrophages containing nonstaining bacterial rods, which were acid‐fast in a Ziehl–Neelsen stain, suggesting mycobacterial infection. Histologic examination of the mass revealed a pyogranulomatous mastitis characterized by an infiltration with macrophages containing acid‐fast bacteria. Mycobacterium kansasii was subsequently cultured and identified by PCR. Surgical excision of the mass resulted in the growth of other dermal masses, but antimycobacterial treatment with rifampin and clarithromycin resolved these masses within 1 month. Three months after discontinuation of the treatment, similar organisms were found in aspirates of the enlarged bilateral inguinal lymph nodes by cytologic examination. Despite antimycobacterial treatment for another 4 months, there was no improvement and demodicosis also recurred. The dog eventually died of lymphoma 5 months after the relapse of mycobacterial infection. Although M kansasii is considered an important pathogen for pulmonary and cutaneous disease in people, there is only one report in a dog with an infection in a pleural effusion. As both adult‐onset demodicosis in dogs as well as mycobacterial infection in people have been associated with T‐lymphocyte deficiency, the M kansasii infection in this dog may have been associated with a condition of immune compromise.     

Cutaneous syndrome possibly caused by heartworm infestation in a dog

A 9-year-old German Shepherd bitch was presented with a recent onset of seborrhoea oleosa, hyperpigmentation, erythema, pruritus and alopecia along the neck, thorax, ventrum and the dorsal area of the carpus. The skin changes were believed to be caused by Dirofilaria immitis infection. A combination of topical and parenteral anti-heartworm therapy led to the resolution of the lesions.     

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.     

Mycobacterium tuberculosis infection in a dog from Africa

A 4-year-old male Boxer dog with a history of vomiting, diarrhea, and weight loss moved from West Africa to Lyon, France, where it was further evaluated. Radiographs revealed pleural effusion and enlargement of tracheobronchial lymph nodes and liver. Cytologic examination of the pleural effusion and a fine needle aspirate specimen of the liver showed mixed mononuclear inflammation with nonstaining rod structures within epithelioid histiocytes. At necropsy, the main gross pathologic findings were exudative pleuritis, nodular hepatitis, and infarcts and caseous nodules in the kidneys. The main histologic lesions were granulomatous hepatitis, granulomatous pneumonia, fibrinous leukocytic pleuritis, necrotic and fibro-calcified granulomatous lymphadenitis, and granulomatous nephritis. A Ziehl-Neelsen stain applied to both cytologic and histologic samples was positive for acid-fast bacilli. Bacterial culture of the pleural fluid was positive for Mycobacterium tuberculosis. Cytology is a valuable tool in the diagnosis of this important zoonotic disease.     

Survival of a dog with pneumonia caused by Mycobacterium fortuitum

Pneumonia caused by Mycobacterium fortuitum was diagnosed in the left lung lobes of a 3-year-old male Samoyed. Unilateral pneumonectomy and antibiotic treatment (primarily amoxicillin trihydrate-clavulanate potassium and kanamycin) were associated with resolution of the pneumonia. In dogs, M fortuitum causes pulmonary disease that radiographically resembles bacterial pneumonia. Therefore, M fortuitum infection should be considered in dogs with radiographic signs of bronchopneumonia that worsen despite antibiotic treatment.     

Outbreak of tuberculosis caused by Mycobacterium caprae in a zoological garden

In the autumn of 2004, tuberculosis caused by Mycobacterium caprae occurred in a zoo in Slovenia. A dromedary camel (Camelus dromedarius) was killed after a history of progressive emaciation. Necropsy findings indicated disseminated tuberculosis, which was confirmed by cultivation of M. caprae. Consequently, a tuberculin skin test was performed in all epidemiologically linked animals and another dromedary camel and six bison (Bison bison) were positive and killed. Mycobacterium caprae was isolated from two bison while M. scrofulaceum and Mycobacterium spp. were found in two other bison, respectively. The second dromedary camel was found to be negative for mycobacteria under both microscopic and culture tests. The isolates were investigated with commercial identification kits, IS6110 PCR, IS6110 restriction fragment length polymorphism analysis, spoligotyping and mycobacterial interspersed repetitive units typing. Genotyping results revealed that the dromedary camel and the two bison were infected by the same M. caprae.     

Chronic tuberculosis caused by Mycobacterium bovis in a domestic donkey in Central Europe

Bovine tuberculosis is a contagious and zoonotic disease of animals and humans. In Europe, the number of reported cases of tuberculosis has decreased. Equidae are relatively rarely infected even in endemic areas. The presented report describes a case of chronic Mycobacterium bovis tuberculosis in a 30-year-old female donkey. The donkey initially presented with persistent lymphadenopathy; however, as the disease progressed, weight loss became apparent. To the authors' knowledge, this is the second confirmed case of tuberculosis in a donkey in Europe.     

Pulmonary Mycobacterium tuberculosis (Beijing strain) infection in a stray dog

Mycobacterium tuberculosis infection in dogs is rarely reported and has not previously been documented in South Africa. A case of a stray Maltese crossbreed dog with extensive multifocal pulmonary tuberculosis due to M. tuberculosis is described. Pulmonary granulomas in this case were poorly encapsulated and contained large numbers of acid-fast bacteria, highlighting the potential for infected companion animals to excrete the pathogen. Treatment of canine tuberculosis is generally not advised, and for this reason, euthanasia of diseased animals must be advocated in most instances. Physicians and veterinarians must be aware that companion animals with active disease caused by M. tuberculosis could act as a potential source of infection.     

Putative transmission of Mycobacterium tuberculosis infection from a human to a dog

A 3.5-year-old Yorkshire Terrier was evaluated for anorexia and vomiting; infection with Mycobacterium tuberculosis was diagnosed by use of histology, bacteriologic culture, and polymerase chain reaction (PCR) assay on various tissues. The dog was living with a human with an established M. tuberculosis infection. Findings were unique in that diagnosis of M. tuberculosis infection was obtained via PCR techniques, and isolates from the owner and dog were matched via restriction fragment length polymorphism fingerprinting. Dogs infected with M. tuberculosis from humans are most commonly infected via the respiratory tract. Clinical signs in dogs are variable and depend on the integrity of the immune system and the degree of dissemination. Diagnosis can often be obtained through histopathology and bacteriologic culture; additional diagnostic techniques are also available. Treatment of a dog with confirmed M. tuberculosis infection is controversial, and at least 6 months of multidrug treatment is required.     

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.     

Disseminated tuberculosis in hyrax (Procavia capensis) caused by Mycobacterium africanum

Tuberculosis due to Mycobacterium africanum was diagnosed in an adult female hyrax (Procavia capensis). Pathologic examination revealed disseminated tuberculous lesions. The same pathologic changes were also found in a male hyrax that died a year later. Both animals were imported from the United Arab Emirates and were held in captivity at the Zagreb Zoo in Croatia. The source of infection remains unknown. The acid-fast bacteria isolated from the lungs of the female hyrax were identifyed by polymerase chain reaction as Mycobacterium tuberculosis complex and Geno Type MTBC test confirmed the strain to be M. africanum I.     

Cutaneous lymphoma in a juvenile dog

Abstract: An 18-month-old male Doberman Pinscher was referred to the Veterinary Medical Teaching Hospital of the College of Veterinary Medicine for an erythemic nodular mass on the right forelimb. The mass was diagnosed as cutaneous lymphoma, based on cytologic examination of a mass aspirate and histopathology. Using immunohistochemistry the neoplastic cells were positive for CD3 but negative for CD79a, E-cadherin, and pancytokeratin, confirming their origin as T lymphocytes. No tumor recurrence was noted 18 months after surgery. To our knowledge, this is the first report of a solitary nodular form of cutaneous lymphoma in a young dog.     

Cutaneous collagen nodules in a dog

A 16-month-old German short-haired pointer was examined because of the development of multiple nodules (0.5-3 cm diameter) in the skin of the head, back, sternum and limbs. The nodules were first noticed when the dog was 8 weeks of age. At no time did the animal show clinical signs of a systemic disease. Histology and electron microscopy revealed that the nodules were composed of irregular bundles of dense collagen fibres and the constituent fibrils had a distribution of diameters similar to that expected in normal skin. Immunofluorescence tests for immunoglobulin (IgG) and complement (C3) showed no deposits of these in the skin and the serum antinuclear antibody test was negative. It was concluded that the nodules were collagenous naevi.