Report On Hookworms (Ancylostoma Duodenale And Necator Americanus)

Clinical Manifestations

“Ground itch” (itching at the site of invasion by the larvae), pneumonitis, cough, dyspnea, and, occasionally, hemoptysis are early svmptoms of hookworm infection.

Symptoms associated with the intestinal phase of infection include anorexia or a huge appetite with pica (desire to eat unusual substances, such as dirt), fever, diarrhea, abdominal discomfort, weight loss, nausea and vomiting, spleen and liver enlargement, and edema. Children may suffer from mental, physical, and sexual retardation. Eosinophilia is usually marked. Hemoglobin levels as low as 2 percent are common in some endemic areas. Even where hookworm infection is widespread, not all infections lead to hookworm disease.

Diagnosis and Identification

Specimen: Stool Hookworm infection is difficult to differentiate clinically from other parasitic infections and certain other diseases. Diagnosis is made by demonstrating eggs in stool specimens. The two species cannot be distinguished on the basis of their eggs. Direct microscopic examination of the stools may suffice in heavy infections, but a concentration method should be used in most cases (e. g. , zinc sulfate flotation or formalin-ethylacetate concentration). An estimate of the intensity of infection can be made on the basis of the number of eggs in a measured fecal sample. Specimens should be examined promptly since rhabditiform larvae may develop and hatch from the egg within a few hours. When larvae are present in the feces, they must be differentiated from those of other nematode species.

Eggs are normally passed in the stool in the unembryonated state (usually about an 8- to 32-cell stage of development). There are typically a thin shell and clear space between the developing embryo and the shell.

If the stool remains unpreserved for over 24 h, the eggs may continue to develop and the larvae may hatch. These larvae must be differentiated from those of S. stercoralis, since therapies for the two infections are different.

The eggs are normally distorted on the permanent stained smear, and morphology is more easily seen in wet preparations.

Identification of Hookworm ova using trichrome stain: The hookworm will have delicate, thin shells that will be ruptured during the staining process and will be rarely visible. Only the embryo, which will be stained red and retaining its size and oval shape, would be seen. Due to the original presence on the shell, there will often be a clear halo around the embryo, which will have a granular appearance. Sometimes the round individual cells of the embryo will be visible. Some plant material resemble these ova but is not as uniformly shaped and has an irregular, thick- walled cellular structure, unlike the granular appearance of hookworm embryos.