Parasitol Int. 2026 Oct 8:103404. doi: 10.1016/j.parint.2026.103404. Online ahead of print.
ABSTRACT
Thelazia callipaeda is an emerging zoonotic eyeworm that infects the ocular tissues of domestic and wild mammals, including humans. This study describes the first molecularly confirmed pediatric case of human ocular thelaziasis caused by T. callipaeda in Türkiye and discusses its epidemiological significance from a One Health perspective. A 2-year-old boy from Kırklareli Province, northwestern Türkiye, presented with ocular itching and stinging sensation of approximately 20 days’ duration. Ophthalmological examination revealed a motile nematode in the temporal conjunctival sac of the right eye. Two live worms measuring approximately 1-2 cm were surgically removed under general anesthesia. Clinical recovery was achieved following extraction and topical therapy, with no recurrence during follow-up. Morphological examination demonstrated characteristic features of an adult gravid female Thelazia nematode, including a transversely striated cuticle, a uterus containing embryonated eggs and first-stage larvae, and a tapered posterior extremity. Molecular identification was performed by amplification and sequencing of a partial mitochondrial cytochrome c oxidase subunit 1 (mt-CO1) gene fragment. BLAST analysis revealed 100% identity with reference T. callipaeda sequences. This report documents the first molecularly confirmed pediatric case of human ocular thelaziasis in Türkiye. The occurrence of infection in the European part of Türkiye, close to endemic Balkan regions, raises the possibility of local transmission, although the absence of concurrent entomological and veterinary investigations precludes confirmation of an autochthonous transmission cycle. Integrated surveillance involving humans, domestic animals, wildlife reservoirs, and vectors is warranted to better understand the epidemiology and public health implications of T. callipaeda in Türkiye.
PMID:42849866 | DOI:10.1016/j.parint.2026.103404