Ancylostomoza Necatoroza

The human hookworms include two nematode (roundworm) species, Ancylostoma duodenale and Necator americanus. You can become infected by direct contact with contaminated soil, generally through walking barefoot, or accidentally swallowing contaminated soil.

Fecal smear showing a single hookworm ova Hookworm infection is diagnosed by detection of ova in feces. Adult worms lay an average of 7000 eggs daily, which are expelled to the environment in feces. Moist, shady, warm soil provides optimal conditions for eggs to survive and hatch into infective larvae. Contact with contaminated soil for 5 to 10minutes allows the larvae to penetrate the human host’s skin.

Hookworm eggs examined on wet mount (eggs of Ancylostoma duodenale and Necator americanus cannot be distinguished morphologically).  

Hookworm infection. Noembryonated egg of Necator americanus in a freshly-passed stool specimen. (eggs of N. americanus and Ancylostoma duadenale are difficult to distinguish from one another, although can be differentiated easily.)

1. Hookworm egg, advanced cleavage (iodine). 2 1.Hookworm egg, advanced cleavage (iodine). 2. Embryonated hookworm egg.

Hookworm infection. Embryonated egg of N Hookworm infection. Embryonated egg of N. americanus in which cell division has begun.

Hookworm infection. Egg of N Hookworm infection. Egg of N. americanus in faeces containing a relatively mature embryo.

Hookworm rhabditiform larva (wet preparation).

Hookworm filariform larva (wet preparation).

1. Adult worm of Ancylostoma duodenale 1. Adult worm of Ancylostoma duodenale.  Anterior end is depicted showing cutting teeth. 2. Adult worm of Necator americanus.  Anterior end showing mouth parts with cutting plates.

Necator americanus A. Necator ranges from 5 to 9 mm for males to 1 cm for females.

B. The sharply bent head is hooked-shaped, and the buccal capsule has a pair of cutting plates that help anchor it to the intestinal mucosa where it sucks blood from the host.

Ancyclostoma duodenale A. duodenale is slightly larger than Necator and has a set of teeth with which it attaches to the mucosa of the upper small intestine. The average daily blood loss for Necator infections is 0.03 mL, whereas it is 0.2 mL for Ancyclostoma.

Tissue section showing a hookworm attached to the small intestinal mucosa, where it deprives the host of nutrients. Iron-deficiency anemia, chronic protein-calorie malnutrition, and weight loss are the most common manifestations of hookworm infection, but abdominal pain and diarrhea may also occur.

Hookworminfection. A short section of infected intestine.

Resected specimen of small intestine showing numerous hookworms attached

This enlargement shows hookworms, Ancylostoma caninum attached to the intestinal mucosa. Barely visible larvae penetrate the skin (often through bare feet), are carried to the lungs, go through the respiratory tract to the mouth, are swallowed, and eventually reach the small intestine. This journey takes about a week.

This patient presented with a hookworm infection involving the toes of the right foot, which is also known as "ground itch". Usually the first sign of infection is itching, and a rash at the site where skin touched contaminated soil or sand, which occurs when the larvae penetrate the skin, followed by anemia, abdominal pain, diarrhea, loss of appetite, and weight loss.

This child with hookworm shows visible signs of edema, and was diagnosed with anemia as well.

Cutaneous larva migrans lesions on lower leg (caused by hookworm larvae of Ancylostoma braziliense and Ancylostoma caninum).

Cutaneous larva migrans lesions of the foot of a 10-year-old girl Cutaneous larva migrans lesions of the foot of a 10-year-old girl. In the United States this dog and cat hookworm infection is most commonly seen in the southeastern states. These raised, serpiginous, pruritic, migrating eruptions may extend rapidly.

Cutaneous larva migrans infection of the foot in an adolescent male

Adult who noted a migrating skin lesion on left thigh for 2 weeks.

Cutaneous larva migrans 48 hours after treatment with oral thiabendazole. Topical thiabendazole also is effective.