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Two cases of Mycobacterium microti among primates in a zoo facility

D B Folkvardsen(1) E Svensson(1) T Lillebaek(1,2)

1:International Reference Laboratory of Mycobacteriology, Statens Serum Institut; 2:Global Health Section, Department of Public Health, University of Copenhagen

Mycobacterium (M.) microti, a slow-growing member of the Mycobacterium tuberculosis complex, has been found across diverse wildlife species, spanning rodents, carnivores, ungulates, primates, and others. Initially regarded as a pathogen primarily affecting small mammals, recent evidence suggests its potential as an emerging zoonotic threat, with sporadic human infections reported. A study in South Africa even identified M. microti as the causative agent in 1.9% of local human tuberculosis cases.

We report two cases of M. microti infections in captive primates at a zoo: one in a tamarin (Saguinus spp.) and the other in a lemur (Lemur catta). Diagnosis initially relied on positive acid-fast staining and PCR results for Mycobacterium tuberculosis complex. Subsequent culturing confirmed M. microti in the tamarin case, even though the culture was contaminated. The primary sample identification was consistent with M. microti for the lemur, the culture is still ongoing.

Despite confirming infection, culturing M. microti from clinical specimens poses significant challenges due to its slow growth rate, necessitating prolonged incubation and specialized media, with a risk of overgrowth by other microorganisms. While culturing was achieved in the tamarin case, efforts continue for the lemur. These challenges emphasize the importance of molecular techniques for swift and accurate diagnosis and the necessity for specialized culture methods. In addition, they underscore the critical need for comprehensive infection control measures and heightened awareness among zoo staff and veterinarians to safeguard both animal and human health.

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