Arteritis, aneurysm and thromboembolic colic caused by migration of Strongylus vulgaris larvae in equids

Background

Strongylus vulgaris remains a significant cause of disease in equids, especially in regions with insufficient deworming practices.

Aims/Objectives

To describe the epidemiological, clinical, pathological, and parasitological findings of vascular and extravascular lesions associated with S. vulgaris in equids.

Methods

A retrospective analysis was conducted on necropsy reports from equids examined at the Animal Pathology Laboratory, Federal University of Campina Grande (2000–2024), targeting cases of vascular lesions associated with S. vulgaris. Epidemiological, clinical, and pathological findings were reviewed. Tissue samples were routinely processed for histopathology, and nematodes within vascular lesions were identified by light microscopy.

Results

Of 938 necropsied equids, 804 (85.7 %) were horses, 89 (9.4 %) donkeys, and 45 (4.7 %) mules. Cranial mesenteric artery (CMA) lesions were identified in 54 animals (5.7 %), comprising 45 horses, 6 donkeys, and 3 mules. Affected equids ranged from 3 months to 30 years of age, and included 29 females and 25 males. Most were mixed-breed (66.7 %), raised under a semi-intensive system (98.1 %), and from states in northeastern Brazil. Nearly all cases (98.1 %) were incidental necropsy findings, except for one fatal case of thromboembolic colic. Gross vascular lesions included segmental focal thickening (92.6 %) or aneurysms (7.4 %), often with intralesional nematodes. Histopathology revealed endarteritis, fibrinocellular thrombi, and intralesional S. vulgaris larvae, identified by parasitological evaluation.

Conclusion

Verminous lesions by S. vulgaris should be considered in the differential diagnosis of vascular and extravascular abnormalities in equids. This study highlights the importance of examining the CMA during necropsies and laparotomies in equids from endemic regions.