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A 3-year-old male neutered Golden Retriever with nasal swelling and lymphadenopathy was diagnosed with diffuse Mycobacterium avium infection. Treatment with 9 months of enrofloxacin, clarithromycin and rifampicin was successful, but relapsed 10 months later with lymphadenopathy, skin plaques and testicular involvement. Repeat treatment for 12 months was effective but 15 months later a second relapse responded to the same therapy which is ongoing with survival from diagnosis of 82 months. A 1-year-old male neutered Portuguese Podengo was diagnosed with polyarthritis and M. avium infection and treated with enrofloxacin, clarithromycin and rifampicin for 4 months but relapsed, subsequently responding to combined pradofloxacin, rifampicin, doxycycline and ethambutol. After 12 months of treatment, M. avium was detected and treatment extended to 17 months before stopping when no organism was detected. Relapse occurred after 6 weeks, responding to retreatment but relapsing (polyarthropathy, lymphadenomegaly) after 15 months, with euthanasia 38 months after diagnosis. Dogs with M. avium are challenging to treat with frequent relapse; however, long-term survival is possible., (© 2024 British Small Animal Veterinary Association.)

Canine mycobacterial disease was first recognised over 100 years ago but is now an emerging concern. All reported cases of tuberculous disease in dogs have been caused by infection with one of three Mycobacterium tuberculosis-complex (MTBC) organisms (M. tuberculosis, Mycobacterium bovis, and Mycobacterium microti). Molecular PCR and interferon-gamma release assays offer alternative or complementary diagnostic pathways to that of specialist culture, which is limited by availability, sensitivity, and the time it takes to get a result. Optimised triple antimicrobial protocols offer an excellent chance of a successful outcome in dogs where treatment can be considered and is attempted. In this review, the clinical presentation, diagnosis, treatment, and prognosis of canine tuberculosis are discussed., Competing Interests: Declaration of Competing Interest Two of the authors (CO; DGM) assisted in establishing the canine IGRA at BioBest Laboratories. They receive no financial benefit from its use. They have no other conflicts of interest to declare. ENB has no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Cases of canine tuberculosis, a zoonotic infection of significant public health significance, are typically only sporadically reported in the literature. For this observational study, case details were collated both retrospectively and prospectively for dogs infected with Mycobacterium tuberculosis-complex (MTBC) organisms. A total of 18 previously unreported cases as well as 565 historically reported confirmed cases were reviewed. A variety of diagnostic techniques were used to make a confirmed diagnosis of tuberculosis (culture, interferon-gamma release assay [IGRA], and PCR). The reference standard for diagnosis is culture; however, this was negative or not attempted in some dogs. Where fully speciated, all cases were caused by infection with one of three MTBC organisms: M. tuberculosis, Mycobacterium bovis, or Mycobacterium microti. This study includes the first documented canine infections with M. microti in the UK. All cases were assigned to one of four clinical groups based on the presenting signs: 44.1% were primarily pulmonary, 14.5% were primarily abdominal, and the remainder were disseminated or miscellaneous. The development of adjunctive tests remains necessary to support early treatment decisions pending reporting of culture for MTBC organisms, which can take weeks to months. Definitive treatment, where attempted, was successful in most cases. Of the 13 dogs treated by the authors with triple combination antimicrobial therapy, a good clinical outcome was seen in 12 (92%) of them., Competing Interests: Declaration of Competing Interest Three of the authors (CO; JCH; DGM) assisted in establishing the canine IGRA at BioBest Laboratories. They receive no financial benefit from its use. They have no other conflicts of interest to declare. ENB has no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

A 1-year-old male neutered Portuguese Podengo dog was presented for lameness, inappetence, pyrexia, diarrhoea and abdominal moderate to severe lymphadenomegaly. Cytology of synovial fluid revealed neutrophilic inflammation in multiple joints suggestive of immune-mediated polyarthritis. Cytology of fine-needle-aspiration material obtained from lymph nodes revealed macrophages with intracytoplasmic, rod-like Ziehl-Neelsen positive staining structures, indicative of mycobacteria. Four-month treatment with enrofloxacin, rifampicin and clarithromycin resulted in clinical improvement and resolution of polyarthritis as evidenced on repeat synoviocentesis, but diarrhoea recurred, Ziehl-Neelsen positive organisms were again found on lymph node cytology and analysis of the 16S rRNA-gene using the Basic Local Alignment Search Tool facility resulted in a match to Mycobacterium avium with 100% sequence identity. Treatment was adjusted to include pradofloxacin, doxycycline, rifampicin and ethambutol and 3 months later the dog is clinically normal. Based on the literature search, this is the first time canine Mycobacterium avium infection associated with immune-mediated polyarthritis is reported. Based on scoping searches, this is the first report of canine Mycobacterium avium infection associated with immune-mediated polyarthritis., (© 2021 British Small Animal Veterinary Association.)

This short communication describes the clinical and morphological findings, diagnosis and treatment of a case of Mycobacterium avium infection in a golden retriever that presented with a progressive nasal swelling and lymphadenopathy. Although well documented in cats, where cutaneous lesions are frequently recognised, canine M avium infection is less commonly reported, and cutaneous lesions are rare. To the authors' knowledge this is the first documented case of canine M avium infection that presented with a cutaneous lesion but no systemic clinical signs. It occurred in a dog with no previously reported breed predisposition and highlights that in cases of cutaneous histiocytic infiltrate in dogs mycobacterial infection should remain a differential diagnosis, even in the absence of suggestive organisms on histopathological examination., Competing Interests: Competing interests: CO’H is in receipt of a grant from Biotechnology and Biological Sciences Research Council., (© British Veterinary Association 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Mycobacterium bovis can cause tuberculosis (TB) in social mammals including lions, cattle and man, but canine infections are considered rare. In 2016/17 we investigated a M. bovis TB outbreak in a pack of approximately 180 Foxhounds within the bovine TB Edge Area of England. We employed a combination of immunological tests including an interferon gamma release assay (IGRA) and a serological assay (DPP VetTB, Chembio). Test-positive hounds were euthanased and subjected to post-mortem examination (PME). Overall 164 hounds were tested; 97 (59%) responded positively to at least one test. Eighty-five (52%) dogs responded to M. bovis antigens by IGRA while only 21 (12.9%) had detectable serological responses. At PME three hounds (3.1%) had visible lesions (VL) due to M. bovis infection, later confirmed by culture. Samples from 24 non-VL hounds were cultured and M. bovis infection was confirmed in a further three hounds (11%). This study is the first investigation and report of an outbreak of M. bovis TB in a canine species. We establish that, in principle, diagnostic tests used for identifying infected individuals of other species can effectively be used in the dog. Further work is urgently needed to establish the sensitivity and specificity of the testing approach used in this study for future clinical application., (© 2018 The Authors. Transboundary and Emerging Diseases Published by Blackwell Verlag GmbH.)