Question

A 7-year old boy went to the laboratory experiencing irritability and lack of sleep due to perianal pruritus. His CBC revealed increase in WBC with Eosinophilia. After sample collection, macroscopic examination revealed small, whitish and thin roundworms. Microscopic examination revealed transparent, elongate to oval and flattened on one side ova.

Questions to answer:

1. What would most likely be the disease and causative agent? Enumerate the common name/s.

2. What laboratory technique is used to collect and identify this parasite?

3. When is the best time for collection? Explain.

4. What are the sample of choice for this parasite?

5. What are the prevention and control for this parasite?

Answer 1

ANSWERS :

1.The most likely disease is Enterobiasis and the causative agent is Enterobius vermicularis.The common name is pinworm.

2.Laboratory technique used to collect and identify this parasite is -

Cellophane tape test or pin worm paddle test.Where an adhesive tape like material is applied to the peri anal area and then examined under microscope.

Examination reveal characteristic ova which are 30 to 50 microns in size and have flattened surface on one side or may reveal the worms.

3.Early in the morning before bathing is the best time of collection of sample because female adult worms deposit their eggs outside anal area during night time.

It should be done for 5 days for higher diagnostic yield as the female worms dont lay eggs every day.

4.Glass slide microscopic analysis for this parasite may be performed looking for ova and female worms.

Specimen is best obtained by dabbing the stretched, unwashed peri anal folds in the early morning with cellophane tape and affixing the specimen on to the slide.

5.Prevention and control of parasite :

• Maintain personal hygeine by washing hands regularly before eating and after changing daipers.
• Taking bath early in the morning to prevent egg contamination should be encouraged in high risk patient.
• Trimming of finger nails.
• Children should be advised to avoid sucking their fingers and touching their perianal area.
• Albendazole given on empty stomach 400mg stat followed by repeat dose after 2 weeks.