In this article we will discuss about Pinworms:- 1. Structure of Pinworms 2. Pathogenesis 3. Treatment and Control of Disease.
Structure of Pinworms:
Pinworms are characterized by an oesophagus with a posterior bulb. Both males and females are with pointed tails. Males are with one or two equal spicules. All are parasites, primarily in vertebrates. There are no intermediate hosts.
Examples of pinworms are Pharyngodon mamillatus from the rectum of lizard, Oxyuris equi in the caecum and colon of horses and Enterobius vermicularis in the caecum, appendix and adjacent parts of intestine in man.
It is the human “pinworm” or “seatworm”. This is the most common parasitic nematode of man through out the world. The distribution is worldwide and more common in cooler countries than in hot climate. It is prevalent in America, Europe, Africa and Canada.
It has been estimated that about 209,000,000 people in the world are infected with this worm. Man is generally thought to be the only host. But these worms have been reported from primates-like chimpanzee and gibbon. Children are more commonly infected than adults.
Males range from 2 to 5 x 0.1 mm in size. Each possesses a strongly curved posterior end. A pair of small caudal alae, supported by anterior and posterior papillae are present at the posterior end. Gubernaculum is absent, there is only one spicule.
Female range from 8 to 13 x 0.5 mm in size each with a long tapering tail. It is a short whitish worm shaped like a narrow spindle. A pair of lateral cephalic alae (“wings”) are situated in the anterior end. The mouth is surrounded by three lips or labia.
The mouth cavity leads to an oesophagus with an extra swelling and a distal bulb. The anus lies at the junction of the middle and posterior thirds of the body. The vulva is situated in front of junction of the anterior and middle thirds of the body.
A gravid female contains about 11,000 eggs. Eggs are usually not deposited in the host’s intestine. They remain in the body of the female worm until she crawls through the host anus, usually at night. A person can sometimes feel worms crawling in his rectum.
The pressure of eggs in female causes her to burst, scattering eggs on the perianal and perineal region of host or on the bedclothes. If the worm does not burst, she rapidly discharges her egg, dies and becomes desiccated. Eggs are scattered on clothes, bedclothes, hands and body of persons infected, and even in the dust of the room.
Eggs measure 50 to 60 x 20 to 30 um, are flattened on the ventral side. They have thick shells. The eggs mature rapidly and are infective within a few hours.
People get infection of pinworm by inhaling contaminated air, sucking fingers or ingesting contaminated food and drink. When mature eggs are swallowed, they hatch in the small intestine. The larvae migrate to the caecum, appendix, colon or ileum where they mature in about a month.
Male and female worms may become attached to the gut wall and produce inflammation. The adult live in the host for 20 to 30 days. The infection thus automatically dies out within a month, if there is no reinfection.
Pathogenesis of Pinworms:
The infection of pinworm is called “Enterobiasis”. The person infected may experience intense itching in the anal region. Children especially, may become irritable and not sleep well. General symptoms are restlessness, nervousness, appendicitis, irritability nausea, constipation, diarrhoea, abdominal pain, insomnia, loss of appetite, bed wetting and grinding the teeth.
In women and girls, pinworm may crawl into the genital opening and cause inflammation and irritation. In girls irritation of genitalia by pinworms leads to an early sexual desire. Lesions in colon and appendix are also associated with pinworm infection.
Treatment and Control of Disease Caused by Pinworms:
Oral dose of Gentian violet is used in treating pinworm infection. Piperazine is the most effective medicine in the treatment of ‘Enterobiasis’. The patients should wash his perianal region with warm water and soap on rising from bed and before going to bed.
1. Good sanitary habits help in controlling reinfection.
2. Frequent laundering of night clothes and bedding.
3. Keeping hands and finger nails clean.
4. Frequent bathing.
5. Keeping rooms as dust free as possible.