Chabertia ovina

Name

Philip Chabert (1737–1814): French scientist and veterinarian in Lyon. Latin: ovis = sheep; esophagus = esophagus. English: Large-mouthed bowel worm.

Geographic Distribution/Epidemiology

Worldwide, mainly in sheep, goats, and rarely in cattle and wild ruminants. In sheep, prevalence rates of up to 90 % were reached.

Morphology/Life Cycle

The cylindric whitish worms reach as males a length of 12-16 mm and as females 20 mm. They are characterized by a large mouth capsule which is surrounded by numerous small cuticular teeth. The esophagus shows a typical constriction. The posterior end of the males is provided with a bursa copulatrix and two long spicula (Fig. 1). The females excrete nonembryonated eggs, which measure 70–100 μm × 40–60 μm. Depending on the temperature, the larva 1 hatches within 5–8 days and develops within 5–10 days into the sheathed infectious larva 3, which is swallowed by the next host or the same host (see Infectious larvae of nematodes). The sheath is...