Isolation and molecular characterization of Mycobacterium bovis causing pulmonary tuberculosis and epistaxis in a Thoroughbred horse.
Authors: Hlokwe Tiny Motlatso, Sutton David, Page Patrick, Michel Anita Luise
Journal: BMC veterinary research
Summary
# Editorial Summary Mycobacterium bovis tuberculosis remains exceptionally rare in equine populations worldwide, yet this 2016 case report from South Africa documents the first fully characterised infection in a horse, presenting clinically as bilateral epistaxis with concurrent pulmonary disease. An eight-year-old Thoroughbred presented with haemorrhage from the trachea on endoscopy and a primary lung mass on radiography; M. bovis was definitively isolated from bronchoalveolar lavage fluid and genetically fingerprinted as spoligotype SB0868, a strain previously undescribed in South African horses. The pulmonary lesion regressed following three months of oral enrofloxacin at 7.5 mg/kg once daily, suggesting better treatment responsiveness than the disease typically demonstrates in cattle and other species. Whilst horses exhibit lower natural susceptibility to M. bovis than ruminants and swine, this case establishes that they can nevertheless acquire and maintain infection, with implications for biosecurity in mixed livestock operations and the need for heightened clinical suspicion when investigating persistent respiratory and epistatic signs. For equine practitioners, the response to fluoroquinolone therapy and the apparent containability of infection in this species may inform both diagnostic approaches and management decisions should similar presentations arise.
Read the full abstract on PubMed
Practical Takeaways
- •Although rare, M. bovis tuberculosis should be considered in the differential diagnosis for horses presenting with chronic respiratory signs and epistaxis, particularly given potential zoonotic transmission risk to handlers
- •Fluoroquinolone monotherapy (enrofloxacin) may offer a treatment option for equine M. bovis infections, with observable clinical improvement achievable within 3 months
- •Horses with M. bovis may be more susceptible and easier to treat compared to cattle and other livestock, making early diagnosis and isolation important for herd health management
Key Findings
- •M. bovis was successfully isolated from broncho-alveolar lavage in an 8-year-old Thoroughbred presenting with bilateral epistaxis and coughing
- •The isolated M. bovis strain (spoligotype SB0868) was novel and had not been previously described in South Africa
- •Pulmonary mass reduced in size following 3 months of oral enrofloxacin therapy at 7.5 mg/kg once daily
- •This is the first fully documented case of M. bovis infection in an equine in South Africa with clinical findings, isolation, and genetic characterization