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[Ancylostoma braziliense] [Ancylostoma caninum] [Ancylostoma duodenale] [Necator americanus]

Adult hookworms reside in the small intestine of their hosts.  Males measure approximately 8-12 mm long and are bursate, with two spicules that do not fuse at their distal ends.  Females measure approximately 10-15 mm long.  Adults of both sexes have a buccal capsule containing sharp teeth.

A	B

A: Adult worm of Ancylostoma duodenale.  Anterior end is depicted showing cutting teeth.
B: Adult worm of Necator americanus.  Anterior end showing mouth parts with cutting plates.

C	D

C: Anterior end of an adult of Ancylostoma caninum, a dog parasite that has been found to produce a rare human infection known as eosinophilic enteritis.
D: Anterior end of an adult female Ancylostoma sp.

E

E: Posterior end of the worm seen in Figure D.