Case report: The gastrointestinal nematode Strongylus vulgaris as a cause of hoof abscess in a donkey

Abstract

Background: Gastrointestinal helminths of the Strongylus genus can be very pathogenic in equids mainly because of migratory larval and subadult stages invading arteries of the mesenterium. However, the extraintestinal, aberrant presence of these stages has been observed.

Case presentation: A 19-year-old male donkey presented with severe lameness in the right front limb. After unsuccessful hoof wraps, diagnostic imaging was performed. Removal of the sole horn led to the discovery of a sizeable abscess containing a single nematode. The helminth was removed and parasitologically examined. The abscess was treated with surgical drainage, wound care, and medicinal fly larvae. Anthelmintic treatment with oral ivermectin (200 µg/kg body weight) was initiated. Parasitological follow-up examinations were conducted two weeks afterwards and at seven and ten months after initial diagnosis. The nematode was identified as adult female specimen of Strongylus vulgaris. Coproscopic examination of the animal and four herd mates confirmed the presence of S. vulgaris in the group. The hoof abscess healed within two months and lameness completely resolved. All parasitological follow-up examination demonstrated anthelmintic efficacy and absence of S. vulgaris, indicating sustained parasite control.

Conclusions: This case represents the first report of ectopic occurrence of S. vulgaris causing a hoof abscess inducing lameness in a donkey. The healing of the abscess was without complications as soon as the source of the condition was removed.

Keywords: Ectopic location; Equid; Lameness; Migrating intestinal nematode; Strongyle parasite.

Fig. 1

Opened abcess cavity with clear view on the worm (arrowhead)

Fig. 2

Morphological characteristics of the retrieved Strongylus vulgaris specimen. Left: Note the typical mouthparts including a globulous buccal capsule with two lobed, rounded teeth (white arrowheads) at its base, a dorsal gutter (yellow arrowhead) reaching the anterior end, and two sets of leaf crowns at its its opening (black arrowheads). Right: Posterior end with vulva. Scale bar 200 μm

Fig. 3

Healing progress of the hoof abscess. Left: The hoof abscess one week after the initial opening. Right: Abscess site one month after initial opening; an even, thin layer of horn is present covering the lesion

Fig. 4

Third-stage larva from coproculture. Characteristic sheathed third-stage larva of Strongylus vulgaris. Total body length: 643.6 μm, total sheath length: 256.4 μm, number of triangular intestinal cells: 32