Necator americanus
is a multicellular parasite with the common name "hookworm". Necator ova are passed in the feces of an infected person and mature into larvae when deposited into the soil. Infection may be contracted when these mature larvae penetrate the intact skin of a bare foot. The larvae enter the circulation, eventually migrating to the small intestine. Here they develop into adult worms, male and female. An adult produces several thousand fertile ova. Deriving their nutrition from the blood of the host, hookworm may cause severe anemia. Diagnosis is accomplished by finding ova in the feces. Each ovum has bluntly rounded ends and a single thin transparent hyaline shell. Because Necator is cylindrically shaped, it is in the phylum Aschelminthes and the class Nematoda (roundworms).
Click on each image to see the enlarged version.
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| 1. male adult 2 X | 2. female adult 8 X | 3. ova 400 X | 4. ova 400 X | 5.ova 400 X |
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| 6. ova 400 X | 7. ova 400 X | 8. ova 400 X | 9. ova 400 X | 10. ova 400 X |
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