Malik, Richard

Objectives: This paper, the last in a series of three on ‘feline leprosy’, provides a detailed description of disease referable to the previously unnamed species, Candidatus ‘Mycobacterium lepraefelis’, a close relative of the human pathogens Mycobacterium leprae and Mycobacterium lepromatosis. Methods: Cases were sourced retrospectively and prospectively for this observational study, describing clinical, geographical and molecular microbiological data for cats definitively diagnosed with Candidatus ‘M lepraefelis’ infection. Results: A total of 145 cases of feline leprosy were scrutinised; 114 ‘new’ cases were sourced from the Victorian Infectious Diseases Reference Laboratory (VIDRL) records, veterinary pathology laboratories or veterinarians, and 31 cases were derived from six published studies. Thirty-eight cats were definitively diagnosed with Candidatus ‘M lepraefelis’ infection. Typically, cats tended to be middle-aged or older when first infected, with a male predilection. Affected cats typically had widespread cutaneous lesions, in some cases after initially localised disease. Advanced cases were often systemically unwell. All cats had outdoor access. The histological picture was lepromatous in the majority of patients, although two cases had tuberculoid disease. In one case that underwent necropsy, lesions were evident in the liver, spleen and lungs. Treatment was varied, although most cats received a combination of oral clarithromycin and rifampicin. Prognosis for recovery was variable, but typically poor. Conclusions and relevance: Candidatus ‘M lepraefelis’ typically causes high bacterial index (lepromatous) feline leprosy that in some cases progresses to systemic mycobacteriosis. The disease has a variable clinical course and prognosis. Many cases either died or were euthanased due to the infection. Multilocus sequence analysis reveals a heterogeneous picture and further analysis of draft genome sequencing may give clues to the taxonomy and epidemiology of this organism. Prospective treatment trials and/or additional drug susceptibility testing in specialised systems would further inform treatment recommendations. Comparative aspects: This paper finishes with a discussion of comparative aspects of infection caused by the three feline leproid disease agents that have been the subject of this series: Candidatus ’Mycobacterium tarwinense’, Mycobacterium lepraemurium and Candidatus ‘M lepraefelis’.

Objectives: This paper, the first in a series of three on ‘feline leprosy’, provides a detailed description of disease referable to Candidatus ‘Mycobacterium tarwinense’, the most common cause of feline leprosy in Victoria, Australia. Methods: Cases were sourced retrospectively and prospectively for this observational study, describing clinical, geographical and molecular microbiological data for cats definitively diagnosed with Candidatus ‘M tarwinense’ infection. Results: A total of 145 cases of feline leprosy were scrutinised; 114 ‘new’ cases were sourced from the Victorian Infectious Diseases Reference Laboratory records, veterinary pathology laboratories or veterinarians, and 31 cases were derived from six published studies. Forty-two cats were definitively diagnosed with Candidatus ‘M tarwinense’ infection. Typically, cats were between 3 and 11 years of age, with no gender predilection, and were generally systemically well. All had outdoor access. Most cats underwent surgical resection of lesions with adjunctive medical therapy, often utilising a combination of oral clarithromycin and rifampicin for at least 3 months. Prognosis for recovery was generally good. Resolution of lesions was not observed in the absence of treatment, but a number of untreated cats continued to enjoy an acceptable quality of life despite persistence of the disease, which extended locally but did not appear to disseminate to internal organs. Preliminary results of draft genome sequencing confirmed that the species is a member of the Mycobacterium simiae complex. Conclusions and relevance: Candidatus ‘M tarwinense’, a fastidious member of the M simiae complex, is capable of causing feline leprosy with a tendency to produce lesions on the head, particularly involving the eyes and periocular skin. The disease has an indolent clinical course and generally responds favourably to therapy despite lesions often containing large numbers of organisms. Detailed genomic analysis may yield clues as to the environmental niche and culture requirement of this elusive organism. Prospective treatment trials and/or drug susceptibility testing in specialised systems would further inform treatment recommendations.

ABSTRACTTwo hemotropic mycoplasmas have been recognized in cats,Mycoplasma haemofelisand “CandidatusMycoplasma haemominutum.” We recently described a third feline hemoplasma species, designated “CandidatusMycoplasma turicensis,” in a Swiss cat with hemolytic anemia. This isolate induced anemia after experimental transmission to two specific-pathogen-free cats and analysis of the 16S rRNA gene revealed its close relationship to rodent hemotropic mycoplasmas. The agent was recently shown to be prevalent in Swiss pet cats. We sought to investigate the presence and clinical importance of “CandidatusMycoplasma turicensis” infection in pet cats outside of Switzerland and to perform the molecular characterization of isolates from different countries. A “CandidatusMycoplasma turicensis”-specific real-time PCR assay was applied to blood samples from 426 United Kingdom (UK), 147 Australian, and 69 South African pet cats. The 16S rRNA genes of isolates from different countries were sequenced and signalment and laboratory data for the cats were evaluated for associations with “CandidatusMycoplasma turicensis” infection. Infections were detected in samples from UK, Australian, and South African pet cats. Infection was associated with the male gender, and “CandidatusMycoplasma haemominutum” andM. haemofeliscoinfection. Coinfected cats exhibited significantly lower packed cell volume (PCV) values than uninfected cats. Phylogenetic analyses revealed that some Australian and South African “CandidatusMycoplasma turicensis” isolates branched away from the remaining isolates. In summary, “CandidatusMycoplasma turicensis” infection in pet cats exists over a wide geographical area and significantly decreased PCV values are observed in cats coinfected with other feline hemoplasmas.