Ancylostoma Duodenale Quiz

Study Notes

Adult worms live in the small intestine of infected persons, mainly in the jejunum, occasionally in the duodenum, and rarely in the ileum.
They are relatively stout, cylindrical, pale pink or greyish white, and may appear reddish brown due to ingested blood.

Involves only one host (human).
Infective stage is the third-stage filariform (L3) larva.
Adult worms attach themselves to the mucous membrane by means of their mouth parts.
Female worms lay eggs, which are passed out in the feces of infected persons.
Eggs develop in the soil, and a rhabditiform larva hatches out, molts twice, and becomes the third-stage infective filariform larva.
A single infective larva develops into a single adult, male or female.

Infection occurs when a person walks barefooted on soil containing the filariform larva, which penetrate the skin and enter the subcutaneous tissue.
Rarely, infection may take place by the oral route.
Transmammary and transplacental transmission has been reported for Ancylostoma.

Inside the human body, the larvae are carried through the venous circulation to the right side of the heart and lungs.
They escape from the pulmonary capillaries into the alveoli, migrate up the respiratory tract to the pharynx, and are swallowed, reaching the small intestine.
During migration, they undergo a third moult and develop a buccal capsule, which they use to attach themselves to the small intestine and grow into adults.

Symptoms can be linked to inflammation of the gastrointestinal system stimulated by feeding hookworms.
Inflammation is accompanied by nausea, abdominal pain, and intermittent diarrhea.
Progressive anemia (iron-deficiency anemia) and protein deficiency states often occur in prolonged infections.
Patients with more severe infections may experience vomiting, general fatigue, and dysentery.
Untreated infections may lead to hemorrhage, edema, and fatal consequences.
Characteristics of chronic hookworm disease include emaciation, wasting, cardiac failure, abdominal distension, and delayed mental and physical development in children.

Hookworm infections begin with larval invasion of the skin, particularly the lower extremities and feet.
Lesions resemble spider bites and insects, causing intense itching (pruritis) and blistering, known as "ground itch" or "toe itch".
Migration of larvae through the skin causes lesions called vesicles containing serous fluids.
Initial areas of lesions appear dry and crusty as the larvae move through the body.
Passage of larvae through the lungs can cause coughing, chest pain, wheezing, and fever.