Oesophagostomum - Morphology

Morphology

Adult worms of all Oesophagostomum spp. exhibit a cephalic groove by its proximal gut as well as a visible secretory pore, or stomum, at the same level of the oesophagus19. Like other nematodes, Oesophagostomum spp. contain a developed, multi-nucleate digestive tract as well as a reproductive system. Their developed buccal capsule and club-shaped oesophagus are useful for distinguishing Oesophagostomum spp. from hookworms.

Both sexes of adults have a cephalic inflation and an oral opening lined with both internal and external leaf crowns. Female adults, which have a length range of 6.5–24 mm, are generally larger than their male counterparts, with a length range of 6-16.6 mm. Males can be distinguished by their bell-like copulatory bursa, located in the tail, and their paired rodlike spicules.

Eggs are ovular in shape and range from 50 to 100 micrometres in size; they closely resembles those of hookworms, which renders diagnosis via stool analysis useless in areas co-infected with both Oesophagostomum and hookworm.