Therapy relies upon a combination of marginal resection of easily accessible lesions and treatment using two or three drugs effective against slowly growing mycobacteria, choosing amongst rifampicin, clarithromycin, clofazimine and pradofloxacin/moxifloxacin.

Although the point-of-care cryptococcal antigen lateral flow assay (LFA) has revolutionized the diagnosis of cryptococcosis in human patients, to date there has been no large-scale examination of this test in animals. We therefore assessed the LFA in cats, dogs and koalas suspected of having cryptococcosis. In sum, 528 serum specimens (129 from cats, 108 from dogs, 291 from koalas) were tested using the LFA and one of two commercially available latex cryptococcal antigen agglutination test (LCAT) kits. The LCAT is a proven and well-accepted method in veterinary patients and therefore taken as the “gold standard” against which the LFA was compared. The LFA achieved a sensitivity of 92%, 100%, and 98% in cats, dogs, and koalas, respectively, with corresponding negative predictive values of 94%, 100%, and 98%. The specificity of the LFA was 81%, 84%, and 62% for cats, dogs, and koalas, respectively, with corresponding positive predictive values of 76%, 48%, and 69%. These findings suggest the most appropriate role for the LFA is as a screening test to rule out a diagnosis of cryptococcosis in cats, dogs, and koalas. Point-of-care accessibility makes it equally suited for use in the field and as a cage-side test in veterinary hospitals. The suboptimal specificity of the LFA makes it less suited to definitive confirmation of cryptococcosis in animals; therefore, all LFA-positive test results should be confirmed by LCAT testing. The discrepancy between these observations and the high specificity of the LFA in humans may reflect differences in the host-pathogen interactions amongst the species.

The principal aim of this study was to optimize the diagnosis of canine neuroangiostrongyliasis (NA). In total, 92 cases were seen between 2010 and 2020. Dogs were aged from 7 weeks to 14 years (median 5 months), with 73/90 (81%) less than 6 months and 1.7 times as many males as females. The disease became more common over the study period. Most cases (86%) were seen between March and July. Cerebrospinal fluid (CSF) was obtained from the cisterna magna in 77 dogs, the lumbar cistern in f5, and both sites in 3. Nucleated cell counts for 84 specimens ranged from 1 to 146 150 cells μL−1 (median 4500). Percentage eosinophils varied from 0 to 98% (median 83%). When both cisternal and lumbar CSF were collected, inflammation was more severe caudally. Seventy-three CSF specimens were subjected to enzyme-linked immunosorbent assay (ELISA) testing for antibodies against A. cantonensis; 61 (84%) tested positive, titres ranging from <100 to ⩾12 800 (median 1600). Sixty-one CSF specimens were subjected to real-time quantitative polymerase chain reaction (qPCR) testing using a new protocol targeting a bioinformatically-informed repetitive genetic target; 53/61 samples (87%) tested positive, C T values ranging from 23.4 to 39.5 (median 30.0). For 57 dogs, it was possible to compare CSF ELISA serology and qPCR. ELISA and qPCR were both positive in 40 dogs, in 5 dogs the ELISA was positive while the qPCR was negative, in 9 dogs the qPCR was positive but the ELISA was negative, while in 3 dogs both the ELISA and qPCR were negative. NA is an emerging infectious disease of dogs in Sydney, Australia.

M lepraemurium causes high bacterial index (lepromatous) or low bacterial index (tuberculoid) feline leprosy. The infection typically causes nodules of the skin and/or subcutis (which tend towards ulceration) on the head and/or forelimbs. The disease usually has an indolent clinical course and infected cats have a generally favourable response to therapeutic interventions, with rare cases undergoing spontaneous resolution. Genomic analysis may yield clues as to the environmental niche and culture requirements of this elusive organism. Prospective treatment trials and/or additional drug susceptibility testing in specialised systems would further inform treatment recommendations.

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'.