Identification of Mycobacterium genavense natural infection in a domestic ferret

Mycobacterium genavense granulomatous typhlocolitis in a horse

A 23-y-old gelding was presented to a veterinary teaching hospital with a history of chronic, refractory diarrhea. Clinically, the horse was in poor body condition, with a thickened and corrugated large intestine identified by transcutaneous abdominal ultrasonography. At postmortem examination following euthanasia, the large colon and cecum had segmental thickening of the intestinal wall with innumerable mucosal ulcers and prominent polypoid mucosal masses. Many mesenteric and hepatic lymph nodes were enlarged. Histology revealed granulomatous and ulcerative typhlocolitis and granulomatous lymphadenitis with myriad acid-fast, variably gram-positive, intrahistiocytic bacilli that stained by immunohistochemistry for mycobacteria. Molecular testing by PCR and sequencing identified the causative agent as Mycobacterium genavense, which is an unusual presentation of infection in a horse.

Mycobacteriosis in a Pet Ferret (Mustela putorius furo) Caused by Mycobacterium xenopi: A Case Report on Neglected Risk of Zoonotic Transmission

Ferrets are highly susceptible to a wide range of mycobacteria, mainly M. bovis, M. avium, and M. triplex. Therefore, ferrets pose a risk of transmission of mycobacteriosis, especially zoonotically relevant tuberculosis. The aim of this study was to describe the findings of M. xenopi mycobacteriosis in a pet ferret and emphasize its zoonotic potential. A pet ferret had a history of weight loss, apathy, hyporexia, and hair loss. Abdominal ultrasound revealed splenomegaly with two solid masses and cystic lesions of the liver. Fine-needle aspiration cytology revealed numerous acid-fast bacilli in epithelioid cells, thus leading to the suspicion of mycobacterial infection. Because of its poor general condition, the ferret was euthanized. Necropsy examination revealed generalized granulomatous lymphadenitis, pneumonia, myocarditis, splenitis, and hepatitis. Histologically, in all organs, there were multifocal to coalescing areas of inflammatory infiltration composed of epithelioid macrophages, a low number of lymphocytes, and plasma cells, without necrosis nor multinucleated giant cells. Ziehl-Neelsen staining detected the presence of numerous (multibacillary) acid-fast bacteria, which were PCR-typed as M. xenopi. This is the first study showing the antimicrobial susceptibility testing of M. xenopi in veterinary medicine, describing the resistance to doxycycline. Overall, our results could facilitate further diagnosis and provide guidelines for the treatment protocols for such infections.

Detection of non-tuberculous mycobacteria in native wildlife species at conservation risk of Argentina

Introduction

Non-tuberculous Mycobacteria (NTM) are mainly environmental but can cause opportunistic infections and diseases in humans and animals. Livestock and wild animals can be infected with NTM. In Argentina, there are native wild species facing conservation risks, and they are the focus of protection and reintroduction projects designed to preserve biodiversity in various ecoregions. The aim of this study was to report the presence of NTM in samples collected from four endangered native wild species from nine Argentine provinces, as part of their pre-release health assessment.

Methods

A total of 165 samples from giant anteater, peccary, tapir and pampas deer were obtained, these included either bronchoalveolar or endotracheal lavages, or oropharyngeal, nasopharyngeal or tracheal swabs. Bacteriological culture followed by molecular identification and sequencing were performed.

Results

A total of 27 NTM were detected, including Mycobacterium avium subsp. hominissuis, M. intracellulare, M. terrae, M. gordonense, M. kumamotonense, M. fortuitum, M. saskatchewanense, and M. genavense. Results revealed a 16,36% NTM recovery rate, with the giant anteater showing the highest prevalence among the mammals under study.

Discussion

In Argentina, due to extensive production systems, the interaction between domestic and wild species sharing the same environment is frequent, increasing the exposure of all the species to these NTM. In this way, the transmission of infectious agents from one to another is feasible. Moreover, NTMs might interfere with the diagnosis of bovine tuberculosis and paratuberculosis. These findings emphasize the importance of active health surveillance in conservation programs. It highlights the need to address NTM epidemiology in wildlife and its impact on conservation and public health.

Concurrent Mycobacterium genavense infection and intestinal B-cell lymphoma in a pet rabbit (Oryctolaguscuniculus)

A 6-year-old male intact pet rabbit was evaluated for chronic weight loss. A large mass was detected by palpation in the mid-abdomen and ultrasound examination suggested a jejunal location. Explorative laparotomy revealed a nodular mass within the jejunal wall. Histological examination of a biopsy revealed mycobacterial granulomatous enteritis with an atypical lymphoblastic proliferation suggestive of lymphoma. Neoplastic lymphocytes were immunopositive for Pax-5 but negative for CD3, which is diagnostic of a B-cell neoplasm. Numerous acid-fast bacteria were seen within histiocytes and identified by polymerase chain reaction as Mycobacterium genavense, which is a non-tuberculous and opportunistic mycobacterium with zoonotic potential. To the best of our knowledge, this is the first documented case of a concurrent B-cell lymphoma and M. genavense infection in a rabbit. Concomitant mycobacteriosis and lymphoma have been rarely described in animals and the coexistence of neoplasia and mycobacterial infection within the jejunum suggests a potential pathogenetic association. Interestingly, the rabbit owner worked in an anti-tuberculosis clinic, and an anthropic origin of the mycobacterial infection could not be excluded.

Clinical, imaging, and pathologic features in cases of neurologic disease in 3 psittacine birds

We used magnetic resonance imaging (MRI) to evaluate the CNS, and confirmed CNS lesions histologically, in 3 psittacine birds with neurologic signs. One bird was recumbent as a result of non-ambulatory paraparesis, and 2 birds were ataxic with impaired proprioception. In all 3 cases, imaging was performed, and infectious diseases were excluded in cases 1 and 2. In case 1, a large mass arose from the left lung; in case 2, a multinodular coelomic mass encompassed the left caudal pulmonary area to the left cranial renal pole; and in case 3, a diffuse hyperintensity affected the lumbar spinal cord. In the first 2 cases, masses invaded the vertebral canal, causing spinal cord compression. All 3 birds were euthanized given the poor prognosis, and postmortem examinations were performed. The final diagnoses were pulmonary adenocarcinoma in cases 1 and 2, and granulomatous and lymphocytic leptomeningitis caused by Mycobacterium genavense in case 3. MRI enabled visualization of the lesions in the affected area of the CNS, and MRI findings were confirmed by histopathology.

Disseminated Mycobacterium genavense infection in a guinea pig (Cavia porcellus): a case report

Background

Mycobacteria are found in many environmental conditions and infect a variety of species, including rodents and rabbits. Guinea pigs are used experimentally as a model for Mycobacterium tuberculosis, but natural mycobacteriosis in guinea pigs has not been reported.

Case presentation

A 1.5-year-old female guinea pig was found acutely deceased with no premonitory illness. On gross post-mortem examination, multifocal to coalescing, raised, firm, pale tan nodules with discrete, irregular margins were noted over the surfaces of all lung lobes. Histopathology revealed nodules composed of clustered foamy macrophages and multinucleated giant cells containing numerous bacterial rods. Similar bacteria-laden macrophages were noted within sections of the liver, heart, palpebral conjunctiva, duodenum, and cecum. Polymerase chain reaction was performed on tissues collected during post-mortem examination. The 16S rRNA gene product was sequenced and was identical to the Mycobacterium genavense type strain.

Conclusions

To the best of the author’s knowledge, this report details the first documented case of Mycobacterium genvaense infection in a guinea pig and a follow up investigation of close-contact animals. Given their experimental susceptibility and this clinical case report, mycobacteriosis should be considered as a differential in guinea pigs exhibiting weight loss in the absence of other clinical signs. With the potential for zoonotic transmission in immunosuppressed individuals, precautions should be taken to safeguard human health in cases of guinea pigs with suspected M. genavense infection.

Pathology of Diseases of Geriatric Exotic Mammals

The review covers select disease conditions most frequently described in aging rodents (rats, mice, hamsters, guinea pigs), rabbits, and ferrets. The conditions are categorized by general organ systems, infectious diseases, and neoplasms. Two data systems, the Veterinary Medical Teaching Hospital and Comparative Pathology Laboratory at the University of California, Davis and Zoo/Exotic Pathology Service, Citrus Heights, California were used in the determining disease conditions to describe.

Update on Diseases in Chinchillas: 2013-2019

Chinchillas have been used mostly as fur animals and as animal models for human ontological diseases and only recently have been recognized as excellent, long-lived, and robust pet rodents. This review aims to provide updated information on emerging disease conditions in pet chinchillas, such as Streptococcus equi subsp zooepidemicus and Pseudomonas aeruginosa. Furthermore, this review article provides updated information on previously documented disorders, such as urolithiasis and middle ear disease, in chinchillas. This article is intended to serve as a complement to the current veterinary reference literature and to provide valuable and clinically relevant information for veterinarians treating chinchillas.