Worms

What is a worm infection?

Worm infestation of the digestive tract by parasites may cause disruption of digestive processes. Worm infections in humans are commonly of two kinds – roundworm infection and pinworm infection.

Roundworm infection:

This infection is caused by an intestinal worm Ascaris lumbricoides. This worm lives in the intestines of humans where it breeds and completes its life cycle. A person is infected by this worm by ingesting its eggs, which may be present in contaminated food. The eggs hatch into larvae which penetrate the intestine and may also be transferred into the blood stream.

An adult ascaris female produces about 200,000 eggs a day which are excreted from the individual's stools. These eggs become infective after some days, and if they are accidentally ingested, they cause the infection. Pigs are often carriers of roundworm eggs. If their faeces are used as fertilizers, crops can become infected with the eggs.

What are the symptoms?

Some of the common symptoms of roundworm infection are:

• Stomach ache and abdominal discomfort
  
• Loss of weight
  
• Increase in appetite
  
• Persistent fever
  
• Coughing and wheezing
  
• Flatulence and a feeling of bloating in the stomach
  
• Nausea and vomiting.

How is it diagnosed?

A stool test is done to check for the presence of roundworm eggs. Sometimes adult worms may be present in the faeces or vomit which are then identified by the patient himself. A blood test may also reveal a high count of white blood cells, which may aid diagnosis. In children, a roundworm infection is usually diagnosed when the child complains of persistent abdominal pain and may also be losing weight without any apparent reason.

What is the treatment?

The most commonly prescribed anti-parasitic agents are mebendazole, albendazole and pyrantel pamoate. The health of the person returns to normal after the infection has been treated.

Pinworm infection:

Pinworms are worms that infect the large intestine, and humans are the only known hosts for this infection. A pinworm infection is usually a continuous infection and may not be easily treatable, since a host often reinfects himself.

The adult pinworm lives in the large intestine and comes out of the anus to deposit its eggs. Since these worms migrate to the anus to lay eggs, the patient has intense itching in the anal area, which is also one of the main symptoms of pinworm infection. This itching is usually most intense at night.

The patient reinfects himself by scratching the itchy area. The eggs get deposited under the finger nails and get ingested when the person eats food. Hygiene is the key to preventing the spread of the infection.

What are the symptoms?

The most common symptom of a pinworm infection is extreme itching around the anus. Apart from that, the patient may lose weight rapidly and without any apparent reason.

How is it diagnosed?

An anal swab is taken, which gets a sample of pinworm eggs. This is then observed under a microscope to confirm the infection.

Hookworm infection:

Hookworm infection is common in subtropical countries and in those which have insanitary conditions. The adult hookworm is a 1 cm long worm that lives in the small intestine, usually in large numbers. They lay eggs which are passed into the soil through the infected person's faeces.

In the warm soil, eggs hatch into infective larvae. When human skin comes in contact with these larvae, they penetrate the skin and are carried to the lungs through the blood stream. Form the lungs, they are swallowed and thus reach the intestine, where they grow and develop. Signs of hookworm infection are manifested 4-6 weeks after the entry of the worms into the body.

What are the symptoms?

In some cases, there may be allergic swelling and redness at the site of penetration. Since the worms attach themselves to the lining of the intestines and draw blood from there, the infected person may show signs of anaemia.

There may be frequent vomiting, cough with blood stained sputum, loose stools and loss of appetite. In a heavy infection, the patient may experience excruciating stomach ache and difficulty in breathing.

How can worm infections be prevented?

Maintaining personal hygiene is the easiest and the most effective way of preventing the infection. For this, one should bathe frequently, use clean clothing and always wash hands after using the toilet and before eating meals. Anti-parasitic agents like mebendazole and albendazole are commonly prescribed.