Stool for Hookworm

 


1. Objective

To detect hookworm eggs in stool samples, confirming infection by Ancylostoma duodenale or Necator americanus.

2. Principle

Hookworm infection is diagnosed by identifying oval, thin-shelled eggs in stool. Detection methods include:

  • Direct wet mount

  • Concentration techniques (formalin-ether) 

  • Culture methods (for larval recovery, e.g., Harada-Mori)

3. Materials

  • Stool specimen container

  • Glass slides and cover slips

  • Normal saline and Lugol’s iodine

  • Formalin and ether (for concentration)

  • Filter paper and tube (for Harada-Mori)

  • Microscope

  • PPE and waste disposal materials

4. Procedure

A. Direct Microscopy

  1. Mix a small stool sample with saline and/or iodine on a slide.

  2. Cover with a slip and examine under 10x and 40x objectives.

  3. Identify hookworm eggs – oval with a clear shell and visible developing embryo.

B. Formalin-Ether Concentration

  1. Mix stool in 10% formalin, filter.

  2. Add ether, centrifuge, and examine sediment.

C. Harada-Mori Culture (for larvae)

  1. Smear a small amount of stool on filter paper strip.

  2. Insert into test tube with water.

  3. Incubate upright at 28–30°C for 7 days.

  1. Larvae migrate to water and can be microscopically examined.

5. Result Interpretation

  • Positive: Presence of hookworm eggs or larvae.

  • Negative: No eggs seen – repeat test or use more sensitive method.

  • Important: Avoid delays—eggs may hatch if stool is not fresh, complicating diagnosis.

6. Uses

  • Confirm intestinal hookworm infection.

  • Support diagnosis of iron-deficiency anemia or eosinophilia in endemic areas.

  • Pre-treatment screening in mass deworming programs.

7. Conclusion

Microscopy remains a reliable and economical method for diagnosing hookworm infection. Prompt sample analysis ensures identification of characteristic eggs before hatching. Advanced techniques like culture or PCR may assist in species identification where needed.

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