A Retrospective Study of 17 Cases of Mycobacteriosis in Domestic Ferrets (Mustela Putorius furo) between 2005 and 2013

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.

Respiratory Disorders in Ferrets

Ferrets are susceptible to many disorders affecting the respiratory tract including both primary diseases and diseases of other body systems secondarily affecting the respiratory tract. Some primary respiratory diseases are shared with other mammal species including humans; potentially zoonotic diseases include important pathogens such as influenza and SARS-CoV-2. Other diseases include infections (bacterial, parasitic, and fungal) and neoplasia. A thorough workup is important to identify exact causes in order to formulate a treatment plan. Infectious diseases include bacterial, fungal, parasitic, and viral.

Intestinal Mycobacterium avium Infection in Pet Dwarf Rabbits (Oryctolagus cuniculus)

Mycobacteriosis has been rarely described in pet rabbits (Oryctolagus cuniculus). Here we present two cases of intestinal mycobacteriosis from north-eastern Germany. The first adult rabbit was euthanized due to severe cardiovascular failure, hypothermia and chronic weight loss. Necropsy revealed cachexia and a focal, fibrinonecrotic lesion in the caecum. Histologically, severe granulomatous inflammation, with numerous multinucleated giant cells and abundant acid-fast bacilli, was detected under the fibrinonecrotic material in the abdominal wall adjacent to the caecal lesion, caecal lymph nodes, spleen, liver and lungs. Microbiological culture detected Mycobacterium avium subspecies hominissuis, Escherichia coli, Clostridium disporicum and Bacteroides ovatus. A retrospective assessment of 2,013 other pet rabbit necropsies, performed between 1995 and 2019, revealed one additional case of intestinal mycobacteriosis. This animal had been euthanized due to persistent hindlimb lameness and necropsy revealed comminuted fractures of the pelvic bones and multiple large liquefied abscess-like lesions in the caecal and colonic walls. Histology revealed granulomatous inflammation with acid-fast bacilli. Polymerase chain reaction on formalin-fixed, paraffin-embedded tissue identified the presence of M. avium spp. In contrast to European wild rabbits (Oryctolagus cuniculus) from Scotland, these findings indicate that intestinal mycobacteriosis is rare in pet rabbits from north-eastern Germany. Zoonotic potential should be considered due to the close contact between pets and their owners and the chronic course of the disease with an initial lack of clinical signs.

Gastrointestinal Diseases of Ferrets

Disease of the gastrointestinal (GI) tract is common in ferrets. This chapter reviews diseases of the upper and lower GI tract in ferrets, discusses how to differentiate between causes of diarrhea and vomiting, and provides information to help formulate an appropriate treatment plan. Clinicians should be familiar with the more common GI disorders in ferrets and be able to recognize clinical signs and differentiate among potential diagnoses.

Identification of Mycobacterium genavense natural infection in a domestic ferret

A 6-y-old neutered male ferret ( Mustela putorius furo) was presented because of a 1-mo history of progressive weight loss, chronic cough, and hair loss. On clinical examination, the animal was coughing, slightly depressed, moderately hypothermic, and had bilateral epiphora. Thoracic radiography was suggestive of severe multinodular interstitial pneumonia. Abdominal ultrasound examination revealed hepatosplenomegaly and mesenteric and pancreaticoduodenal lymphadenopathy. Fine-needle aspiration of the pancreaticoduodenal lymph node, followed by routine Romanowsky and Ziehl-Neelsen stains, revealed numerous macrophages containing myriad acid-fast bacilli, leading to identification of mycobacteriosis. Autopsy and histologic examination confirmed the presence of disseminated, poorly defined, acid-fast, bacilli-rich granulomas in the pancreaticoduodenal and mesenteric lymph nodes, intestines, and lungs. Destaining of May-Grünwald/Giemsa-stained slides with alcohol, and then restaining with Ziehl-Neelsen, revealed acid-fast rods and avoided repeat tissue sampling without affecting the Ziehl-Neelsen stain quality and cytologic features. Tissue samples were submitted for a PCR assay targeting the heat shock protein gene ( hsp65) and revealed 100% homology with Mycobacterium genavense. We emphasize the use of special stains and PCR for identification of this potential zoonotic agent.

Ocular Examination and Corneal Surface Disease in the Ferret

This article provides a brief, clinically relevant review of corneal surface disease in the ferret. A description of the ophthalmic examination of the ferret is provided. Stepwise descriptions of the most common ophthalmic abnormalities are provided, along with common rule-outs.

Case of mycobacteriosis in a pet ferret in Poland

A seven-year-old dead pet ferret (Mustela putorius furo) was brought to the National Veterinary Research Institute, Department of Microbiology, to have the disease diagnosed and cause of death determined. Significant loss of fur and various numerous skin lesions—such as nodules, bruises and small scabs— were found. A prominent subcutaneous cyst filled with semiliquid mass was observed on the right hindlimb, and the left eyelid was slightly swollen left eyelid with symptoms of conjunctivitis. On the basis of combined findings, the authors concluded that the ferret’s death was caused by a generalized Mycobacterium aviumsubspecies avium infection. Some immunodeficiency resulting from ferret’s age could be a predisposing factor. A feral cat, which was the only animal the ferret had contacted several weeks before the appearance of the first clinical symptoms, was a possible source of infection.

Transmission of Mycobacterium xenopi to a pet albino ferret (Mustela putorius furo) from a domestic aquarium

A three-year-old ferret presented with a three-month history of rapid clinical deterioration necessitating euthanasia shortly after initial veterinary assessment. Postmortem PCR testing confirmed Mycobacterium xenopi which is most commonly identified in amphibians, reptiles and aquatic life. Infection of a captive-bred domestic ferret is highly unusual. A collaborative effort involving medical doctors, clinical veterinarians and veterinary pathologists investigated the potential sources of human-animal, animal-animal and environmental-animal M xenopi transmission. No human-animal or animal-animal risks were identified. As the affected ferret was the only ferret to have regular exposure to the owner's aquarium, a postmortem study of a dead guppy and aquarium water analysis were performed which confirmed mycobacteriosis. Although M xenopi was not specifically cultured, as a slow-growing organism, M xenopi may have been outgrown by more rapidly growing mycobacteria or Gram-positive bacilli present in the water. Thus, transmission of M xenopi via aquarium exposure was certainly plausible. This is the second documented case of M xenopi in a ferret and the first to determine a source of infection. This report highlights the previously recognised risk of mycobacterial exposure from aquaria and that caution is required before allowing domestic ferrets to have contact with potentially infected water reservoirs due to its fatal nature in this vulnerable species.

Molecular characterization and drug susceptibility profile of a Mycobacterium avium subspecies avium isolate from a dog with disseminated infection

Mycobacterium avium-intracellulare complex (MAC) infections have been described in many mammalian species, including humans and pets. We isolated and molecularly typed the causative agent of a rare case of disseminated mycobacteriosis in a dog. We identified the pathogen as M. avium subspecies avium by sequencing the partial genes gyrB and rpsA. Considering the zoonotic potential of this infection, and in an attempt to ensure the most effective treatment for the animal, we also determined the drug susceptibility profile of the isolate to the most common drugs used to treat MAC disease in humans. The pathogen was tested in vitro against the macrolide clarithromycin, as well as against amikacin, ciprofloxacin, rifampicin, ethambutol and linezolid, by the resazurin microdilution assay. It was found to be sensitive to all tested drugs apart from ethambutol. Despite the fact that the pathogen was sensitive to the therapies administered, the dog's overall clinical status worsened and the animal died shortly after antimicrobial susceptibility results became available. Nucleotide sequencing of the embB gene, the target gene most commonly associated with ethambutol resistance, showed new missense mutations when compared to sequences available in public databases. In conclusion, we molecularly identified the MAC pathogen and determined its drug susceptibility profile in a relatively short period of time (7 days). We also characterized new genetic mutations likely to have been involved in the observed ethambutol resistance. Our results confirmed the usefulness of both the gyrB and the rpsA genes as biomarkers for an accurate identification and differentiation of MAC pathogens.