Ancylostoma duodenale is small cylindrical worm, greyish-white in color. It has two ventral plates on the anterior margin of the buccal capsule. Each of them has two large teeth that are fused at their bases. A pair of small teeth can be found in the depths of the buccal capsule. Males are 8 mm to 11 mm long with a copulatory bursa at the posterior end. Females are 10 mm to 13 mm long, with the vulva located at the posterior end; females can lay 10,000 to 30,000 eggs per day. The average lifespan of Ancylostoma duodenale is one year.
When a filariform larva (infective stage) penetrates the intact skin, the larva enters the blood circulation. It is then carried to the lungs, coughed up, and swallowed back into the small intestine. The larva later matures into an adult in the small intestine and female worms can lay 25,000 eggs per day. The eggs are released into the feces and reside on soil. Embryonated eggs on soil will hatch into juvenile 1 stage (rhabditiform or noninfective stage) and mature into filariform larvae. The filariform larvae can then penetrate another exposed skin and begin a new cycle of infection.
Ancylostoma duodenale is prevalent in southern Europe, northern Africa, India, China, and southeast Asia, small areas of United States, the Caribbean islands, and South America. This hookworm is well-known in mines because of the consistency in temperature and humidity that provide an ideal habitat for egg and juvenile development. It is estimated 1 billion people are infected with hookworms. Transmission of Ancylostoma duodenale is by contact of skin with soil contaminated with larvae.