Identification of Bartonella henselae in an aborted equine fetus.
Authors: Johnson R, Ramos-Vara J, Vemulapalli R
Journal: Veterinary pathology
Summary
# Editorial Summary: Bartonella henselae as a Novel Equine Abortifacient Although *Bartonella henselae*—a pathogen responsible for cat scratch disease and endocarditis in humans—has been isolated from several mammalian species including equids, its role in equine reproductive failure remains undocumented until this case report. Johnson and colleagues employed multiple diagnostic approaches (histopathology, immunohistochemistry, electron microscopy, and molecular analysis including 16S rRNA gene sequencing) to characterise bacteria recovered from an aborted equine fetus, confirming 99.9% homology to *B. henselae* whilst ruling out conventional equine abortion pathogens. The aborted foetus exhibited characteristic necrotising vasculitis across multiple tissues harbouring intralesional Gram-negative coccobacilli, with bacterial presence confirmed via PCR targeting species-specific genes and monoclonal antibody labelling. This represents the first documented case linking *Bartonella* infection to equine abortion, suggesting practitioners should consider this emerging pathogen in diagnostic workups of unexplained fetal loss, particularly where conventional pathogens have been excluded and vasculitic lesions predominate; further epidemiological investigation is warranted to establish whether *B. henselae* represents a sporadic finding or an underrecognised cause of reproductive disease in horse populations.
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Practical Takeaways
- •Bartonella henselae should be considered as a potential cause of equine abortion; include molecular testing in diagnostic workup of aborted foals when routine pathogens are negative
- •This zoonotic organism can infect multiple species—practice appropriate biosafety when handling aborted tissues and consider exposure risk if pregnant mares are exposed to infected cats or tick vectors
- •Pathological findings of vasculitis with intralesional bacteria warrant investigation for Bartonella even in regions where it was previously thought uncommon in horses
Key Findings
- •Bartonella henselae was identified in an aborted equine fetus using PCR, 16S rRNA sequencing (99.9% homology), and immunohistochemistry
- •The fetus exhibited severe vasculitis and necrosis in multiple tissues with intralesional Gram-negative bacteria
- •This is the first documented case linking B. henselae infection to abortion in equids
- •Other known equine abortion pathogens were ruled out through diagnostic testing