Trichuris ovis: Prevalence, Molecular Advances, Immunopathogenesis, and Diagnosis of a Neglected Ruminant Whipworm

Trichuris ovis is a widespread whipworm of the cecum and colon of domestic ruminants, transmitted through resistant eggs that persist on pastures for years. Although most infections are subclinical, heavy infections in young animals cause typhlitis and colitis. This narrative review summarizes current knowledge on T. ovis, emphasizing molecular systematics, immunopathogenesis, and diagnosis. Complete mitochondrial genomes have confirmed T. ovis as distinct from T. discolor and T. skrjabini, but discordance between ribosomal and mitochondrial markers leaves its relationship with T. globulosa unresolved and suggests cryptic lineages. Reported prevalence ranges from below 1% to over 70% and depends on the diagnostic method, as coprological examination cannot distinguish Trichuris species. Immunological knowledge derives mainly from the T. muris model, in which T helper 2 (Th2) responses mediate worm expulsion and excretory–secretory proteins modulate host immunity, whereas data for ruminants remain scarce. Flotation solutions of higher specific gravity improve egg detection, and combined nuclear and mitochondrial markers are required for reliable species identification. Control should rely on integrated parasite management that prioritizes reducing environmental contamination. Remaining gaps include anthelmintic efficacy and resistance in T. ovis and molecular data from underrepresented regions, including the Balkans.