Ancylostoma duodenale / Necator americanus

Eggs of Ancylostoma and Necator

Size: 60-75 µm by 35-40 µm

• are thin-shelled
• colorless  
• Has a typical space between shell and developing embryo
• Microscopically you cannot differentiate them. 

A Shell
B Cells

Adult hookworms

• reside in the small intestine of their hosts

A. duodenale males :

• Length: 8-12 mm
• Buccal capsule containing sharp teeth
• Bursa copulatrix (two spicules)

A. duodenale female:

• Length: 10-15 mm
• Buccal capsule containing sharp teeth

N. americanus males

• Length: 5-9 mm
• Buccal capsule containing cutting plates
• Bursa copulatrix (two spicules that are fused at the distal end)

N. americanus females

• Length: 9-11 mm
• Buccal capsule containing cutting plates 

Rhabditiform larvae (=stage 1)

Length: 250 μm