Ancylostoma braziliense is related to the main nematode worms known as human hookworms, A. duodenale and Necator americanus. In contrast to these two species, however, although A. braziliense nematodes can penetrate the human skin (causing cutaneous larval migrans), they do not develop any further. Cutaneous larval migrans (also known as "creeping eruption" or "ground itch") is a zoonotic infection (i.e.,an infection transmitted from non-human animals to humans) caused by hookworm species that do not use humans as a definitive host. The condition results from migrating larvae that cause an intensely itchy track in the upper dermis and is most commonly caused by A. braziliense and A. caninum (the normal definitive hosts for these species are dogs and cats).
The normal life cycle for A. braziliense is very similar to the cycle for human hookworms in humans: Eggs are passed in the stool and under favorable conditions (moisture, warmth, shade) larvae hatch in 1 to 2 days. The released rhabditiform larvae grow in the feces and/or the soil and after 5 to 10 days (and two molts) they become filariform (third-stage) larvae that are infective. These infective larvae can survive 3 to 4 weeks in favorable environmental conditions. On contact with the animal host, the larvae penetrate the skin and are carried through the blood vessels to the heart and then to the lungs. They penetrate into the pulmonary alveoli, ascend the bronchial tree to the pharynx, and are swallowed. The larvae reach the small intestine, where they establish themselves and mature into adults. Adult worms live in the lumen of the small intestine, where they attach to the intestinal wall. Some larvae become arrested in the tissues, and serve as source of infection for pups via transmammary (and possibly transplacental) routes. Humans may also become infected when filariform larvae penetrate the skin. In a human host, the larvae cannot mature further, but may migrate aimlessly within the epidermis, sometimes as much as several centimeters a day. Some larvae may persist in deeper tissue after finishing their skin migration. (Source: Centers for Disease Control Parasites and Health Website)
Ancylostoma braziliense has a mainly tropical and subtropical distribution; in the United States it occurs in the Gulf Coast region (Zajac and Conboy 2006).
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