Heterobilharzia americana infection and congestive heart failure in a llama (Lama glama).
Authors: Corapi W V, Eden K B, Edwards J F, Snowden K F
Journal: Veterinary pathology
Summary
# Editorial Summary: Heterobilharzia americana in a Llama with Cardiac Disease Heterobilharzia americana, a freshwater schistosome parasitic in mammals across the southeastern United States, had never been documented in camelids until this 2015 case report—despite being recognised in equine populations. A 6-year-old llama presented with congestive heart failure caused by extensive parasite-induced granulomatous inflammation, particularly affecting the lungs and liver, with histological examination revealing myofiber degeneration, necrosis and significant replacement fibrosis throughout the myocardium; PCR confirmation identified H. americana in lung tissue. The widespread cardiac pathology suggests this schistosome can cause severe myocardial damage in non-traditional hosts, warranting heightened clinical awareness amongst practitioners working with camelids in endemic regions. Given the parasite's established presence in equine populations and shared grazing environments, veterinarians and farriers should maintain suspicion for H. americana infection when camelids or horses present with unexplained cardiac dysfunction or granulomatous disease, particularly in the American Southeast. This case expands our understanding of H. americana's host range and highlights the zoonotic potential of parasitic infections in mixed-species operations.
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Practical Takeaways
- •Heterobilharzia americana should now be considered in the differential diagnosis for camelids presenting with cardiac disease and congestive heart failure, particularly in the southeastern United States
- •Clinicians should be aware that this schistosome parasite can affect a broader host range than previously documented, expanding beyond equine and traditional mammalian hosts
- •Histopathological examination combined with PCR confirmation is necessary for definitive diagnosis of H. americana infection in unusual host species
Key Findings
- •First documented case of H. americana infection in a camelid (llama), previously only reported in horses and other mammalian species in southeastern United States
- •Extensive cardiac pathology including myofiber degeneration, necrosis, and replacement fibrosis resulted in congestive heart failure
- •Parasite-induced granulomas were widely disseminated throughout lungs and liver
- •PCR amplification and sequencing confirmed H. americana presence in affected tissues