Stages of Hookworm Larvae

Hookworms are intestinal parasites capable of infecting dogs, cats and humans. These parasites typically enter the body through the skin or are ingested from an infected animal, but may also infest puppies through breast milk or the placenta. These parasites feed off of the host's blood causing weight-loss and other symptoms similar to anemia.

  1. Egg Cycle

    • Hookworm larvae begin life in the form of eggs in the small intestine of the host. From there, they are expelled along with the host's feces, where they enter the hatchling stage. The egg stage of the hookworm life cycle is not infectious of itself, but is one of primary methods that hookworms use to spread from one host to another.

    Infectious Stage

    • After hatching from its egg, the hookworm enters the hatchling phase. After being expelled from the body, the typical hookworm requires five days to hatch, pass through the hatchling phase and grow into the larval stage. At the larval stage, the hookworm is infectious and may be ingested or infect a host through skin contact.

    Larval Stage

    • After entering the host, the larval hookworm may act in several ways depending on the host and how they were absorbed into its body. Larvae that were ingested will make their way to the small intestine, where they will mature into the fourth stage of the hookworm life cycle. Other larvae may travel to other areas of the host to remain dormant until activated by pregnancy or the removal of the adult hookworms in the host. Hookworm larvae may also migrate to the lungs where they will mature into the fourth stage before forcing the host to cough them up and swallow them, sending them to small intestine to breed.

    Adult Stage

    • Hookworms in the fourth, adult stage are typically found in the small intestine, where they feed on the blood of the host and mate. Adult hookworm larvae feed by digesting part of the mucosal lining of the small intestine, forming a small ulcer. The hookworm then injects anticoagulants into the ulcer to stimulate blood flow for feeding. Adult worms in the small intestine may last from four months up to two years.