Hookworms

Infection is acquired by walking barefoot on contaminated soil which leads to larvae penetrating human skin. Rarely larvae are transmitted by ingestion. Necator americanus and Ancylostoma duodenale are pathogenic hookworms. Infective forms are filariform larvae. On contact with the human 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 reside and mature into adults. Adult worms live in the lumen of the small intestine, where they attach to the intestinal wall with resultant blood loss by the host. In addition, infection by A.duodenale may probably also occur by the oral and transmammary route.

High-intensity hookworm infections occur among both school-age children and adults. anemia and protein deficiency caused by blood loss at the site of the intestinal attachment of the adult worms. [What type of anemia will be caused in hookworm disease?]. When children are continuously infected by many worms, the loss of iron and protein can retard growth and mental development. Site of entry of larvae may show dermatitis and itching. Bronchitis and pneumonia may occur from larvae migration. Diagnosis is by the demonstration of hookworm eggs in stool samples.

Hookworm egg in an unstained wet mount, taken at 400x magnification.

Filariform (L3) hookworm larva in a wet mount.