Question

The teacher noticed that Carrie seemed quite restless today and was having difficulty concentrating on any task that she started. She continuously squirmed, whether in her chair or sitting on the floor. On a number of occasions, the teacher also observed Carrie tugging at her underwear and scratching her bottom. She recalled that Carrie’s mother had mentioned something about getting her younger brother tested for pinworms and wondered if this might be what she was observing.
Required:
If Carrie does have pinworms, for what length of time should the other children be observed for similar problems?

Answer 1

Answer: Other children should be observed after the average of 6 weeks from the time of exposure to Carrie who is suspected to be infected by Pin worm.

Explanation:

Pin worm also called enterobiasis vermicularis is a parasitic nematode. The eggs are found in the specimen collected from the perianal skin and in the faeces of an infected individual. In its worldwide distribution, children are more commonly infected than adults. This is so because autoinfection by swallowing infective eggs is common in children. The eggs cause intense irritation and scratching of the infected area leads to the fingers becoming contaminated with eggs. This was observed by Carrie's teacher, as she usually scratch her bottom.

Other children should be observed after the average of 6 weeks from the time of exposure to infective eggs. This is because of the direct life cycle exhibited by the worm. Following ingestion of infective eggs, the larvae hatch in the intestine. Occasionally larvae hatch from the eggs on the perianal skin and migrate back into the intestine where they grow into mature worms. This type of infection is called RETROINFECTION. The larvae develop into fully mature worms in the large intestine. The female worms migrate to the rectum, pass out of the anus and lay their eggs on the perianal skin and perineum. The eggs are produced about 6 weeks after infection. They can remain viable on bedding, clothing, household objects, and in dust for several weeks.

Therefore from the life cycle of the worm, similar problem found in Carrie can be observed in other children after about six weeks of exposure to the infective eggs of the worm.