Mycobacterium microti at the Environment and Wildlife Interface

Area of Science:

• Veterinary Microbiology
• Wildlife Epidemiology
• Zoonotic Disease Research

Background:

• Mycobacterium microti has been unexpectedly prevalent in Northern Italian wild boar populations since 2003.
• The ecological factors sustaining M. microti transmission within these wildlife populations remain poorly understood.

Purpose of the Study:

• To investigate the role of wild rodents and environmental reservoirs (water, soil) in the maintenance and transmission of M. microti.
• To clarify the epidemiological links between M. microti in wild boar, rodents, and their shared habitats.

Main Methods:

• Real-time PCR was used to screen 120 wild animals and environmental samples from wild boar aggregation sites for the Mycobacterium tuberculosis complex (MTBC).
• Positive samples were further analyzed for M. microti identification and genetic profiling.
• Environmental samples included water and mud collected from watering holes and other common areas.

Main Results:

• Six of 120 animals tested positive for M. microti, with one isolate genetically matching strains found in local wild boar.
• MTBC DNA was detected in 3 of 20 water samples and 1 of 19 mud samples.
• The vole-associated spacer oligotype SB0118 was identified in one environmental sample.

Conclusions:

• Wild rodents, specifically Apodemus sylvaticus, Microtus sp., and Apodemus flavicollis, are implicated in the M. microti cycle.
• Contaminated environments, such as watering holes, and rodent excreta likely contribute to M. microti transmission to wild boar.