Zoonotic Transmission of Cutaneous Larva Migrans

Mature hookworms multiply in the small intestine, usually of animals, and eggs are passed in the animal’s stool.

Under favorable conditions (moisture, warmth, shade), larvae hatch from the eggs in 1 to 2 days. The released larvae grow in the stool and/or the soil.

After 5 to 10 days, the larvae become infective. These infective larvae can survive 3 to 4 weeks in favorable environmental conditions.

Once the larvae have contact with the animal, they penetrate the skin and are carried through the blood vessels to the heart and then to the lungs, where they then reach the throat and are swallowed.

The larvae reach the small intestine where they mature into adults. Adult worms live in the small intestine where they attach to the intestinal wall. Some larvae stop maturing and are halted in the larval stage in the tissues; these particular larvae serve as the source of infection for puppies and kittens via their mother's milk

Humans become infected when larvae penetrate the skin. With most species, the larvae cannot mature further in the human host and move around within the topmost layer of the skin, sometimes as much as several centimeters a day. Some larvae may become trapped in deeper tissues.