Hookworm
Hookworm is a parasitic nematode that lives in the small intestine of its host, which may be a mammal such as a dog, cat, or human. Two species of hookworms commonly infect humans,
Ancylostoma duodenale and
Necator americanus.
A. duodenale predominates in the Middle East, North Africa, India and in southern Europe, while
N. americanus predominates in the Americas, Sub-Saharan Africa, Southeast Asia, China, and Indonesia. The
A. braziliense and
A. tubaeforme species infect cats, while
A. caninum infects canines.
Uncinaria stenocephala infects both dogs and cats.
A. caninum has infected humans, with 150 cases reported in Brisbane, Australia from 1988-1992. Hookworms are much smaller than the giant roundworm
, and the complications of tissue migration and mechanical obstruction so frequently observed with roundworm infestation are less frequent in hookworm infestation. The most significant risk of hookworm infection is anemia, secondary to loss of iron in the gut. The worms suck blood voraciously and damage the mucosa. However, the blood loss in the stools is not visibly apparent.