Host-Pathogen Interactions of Mycobacterial Infections in Wildlife

Mycobacterial infections in wildlife arise primarily from members of the Mycobacterium tuberculosis complex, notably M. bovis and M. tuberculosis, which can circulate among wild mammals, livestock and human populations. The outcome of these infections is determined by a dynamic interplay between pathogen virulence factors and host immune defences. Innate responses, led by macrophages and dendritic cells, initiate phagocytosis and cytokine secretion, while adaptive immunity orchestrates T-cell-mediated control. Central to containment is the formation of granulomas—structured aggregates of immune cells that sequester bacteria but may also become sites of pathology if regulatory balance is lost. Pathogen strategies, including inhibition of phagosome maturation and modulation of host cytokine profiles, enable persistence. Wildlife reservoirs such as African buffalo, elephants, bears and small carnivores can sustain transmission cycles, posing threats to conservation, agriculture and public health. Understanding these interactions underpins one health approaches, informs targeted surveillance and supports the development of diagnostics, vaccines and management protocols to curb spillover at the wildlife–livestock–human interface.

Research from Nature Portfolio

Whole genome sequencing of tuberculosis outbreaks in captive sun bears and an Asiatic black bear has revealed that human-derived strains of M. tuberculosis can efficiently infect and spread among bear populations. Single nucleotide polymorphism analysis combined with epidemiological metadata delineated two independent outbreaks and identified a human intermediary in one chain of transmission. High rates of progression to active disease in these ursids demonstrate their exceptional susceptibility under captive conditions. These genomic insights afford a detailed map of transmission routes and mutation patterns, guiding veterinary management, biosecurity measures and the design of targeted interventions in wildlife rescue and rehabilitation settings.

Host-Pathogen Interactions of Mycobacterial Infections in Wildlife publication trend

The graph below shows the total number of articles in host-pathogen interactions of mycobacterial infections in wildlife across all publications each year (not limited to Nature Index journals).

Technical terms

Granuloma: A structured collection of immune cells, primarily macrophages and lymphocytes, formed to contain persistent pathogens such as mycobacteria.

Zoonotic transmission: The passage of a pathogen from non-human animals to humans, or vice versa.

Spoligotyping: A molecular typing technique based on the presence or absence of spacer sequences in the direct repeat region of mycobacterial DNA.

Whole genome sequencing (WGS): Comprehensive determination of the complete DNA sequence of an organism’s genome, enabling fine-scale analysis of pathogen evolution and transmission.

One Health: An integrated framework recognising the interconnected health of humans, animals and ecosystems in disease prevention and control.

References

1. Genomic insights into anthropozoonotic tuberculosis in captive sun bears (Helarctos malayanus) and an Asiatic black bear (Ursus thibetanus) in Cambodia. Scientific Reports (2024).
2. Understanding the development of tuberculous granulomas: insights into host protection and pathogenesis, a review in humans and animals. Frontiers in Immunology (2024).
3. Identification and molecular characterization of Mycobacterium bovis DNA in GeneXpert® MTB/RIF ultra-positive, culture-negative sputum from a rural community in South Africa. One Health (2024).
4. Fatal Tuberculosis in a Free-Ranging African Elephant and One Health Implications of Human Pathogens in Wildlife. Frontiers in Veterinary Science (2019).