What Is Hydatid Disease?

Hydatid disease affects the liver, and sometimes the lungs. Cysts develop and grow. Cysts are “pockets” inside the body. Their growth can cause problems with body function, or they can become infected and make someone dangerously ill.

The authors report that, for a long time, hydatid disease was thought to be a problem only in underdeveloped countries such as India and the continent of Africa, but recently it has been increasing in developed countries such as Australia, New Zealand and Central Europe. It has not yet been found in North America.

What Causes Hydatid Disease?

Hydatid disease is caused by a tapeworm parasite known as Echinococcus. (For this reason, the disease is also known as echinococcosis.) There are many types of Echinococcus tapeworms, but the two types that cause disease in humans are called Echinococcus granulosus and Echinococcus multilocularis.

What Is a Parasite?

A parasite is a living thing that can only survive if it “attaches” to another living thing. It lives on or in this other living thing, known as a host. The worms that get into our bodies are parasites and we are the hosts. There are many types, including threadworm (the type that commonly affects children) and tapeworm (sometimes causing hydatid disease or other diseases). In hydatid disease, the tapeworms attach to the intestine and lay eggs. The eggs hatch larvae, which travel to other body organs, resulting in the cysts.

How Is Hydatid Disease Identified?

A blood test can show whether a person is infected with the Echinococcus tapeworm, but not the specific type. An ultrasound scan can show cysts in the liver, but not the cause of these cysts. An ultrasound is a painless, harmless way of “seeing” inside the body using soundwaves to create a computer picture.

Sometimes, a person has no symptoms, and it is only discovered by chance, such as when they have a blood test or have their liver tested or scanned for other problems. Other times, a person has a growing cyst causing problems because it is pressing on body organs. Or a person may have an infected cyst, causing them to be unwell because of the infection or the cyst bursting.

How Is Hydatid Disease Treated?

Hydatid disease is best treated with a combination of taking a medicine and having the cysts drained and cleaned. Sometimes a bigger operation is needed, if the cyst is very large or complicated.

The medicine used is called albendazole. This medicine is considered safe for long-term use and has no serious side effects.

If the cysts need draining, this happens as a minor operation. This technique is known as PAIR, which is a word that represents 4 steps:

• Puncture of the cyst wall: A needle syringe is passed through the stomach skin and into the cyst. Ultrasound is used to guide where to go.
• Aspiration of contents: The cyst is drained, or the contents “sucked out” using the needle.
• Installation of scolicidal agent: The cyst is cleaned by flushing it out with cleaning fluid (called scolicidal agent).
• Reaspiration of scolicidal agent: The cyst is emptied of the cleaning fluid.

If the cyst is very large, infected, or burst, then a bigger operation is needed. The person may be quite unwell at this point, so the surgery is important for recovery.

How Can We Avoid Getting Hydatid Disease?

The authors of the paper describe the process of how the worms that cause hydatid disease are passed between humans and animals and advise that personal hygiene is important. The WHO also recommend this to avoid getting any form of worms. We should wash our hands before eating and after using the toilet so that eggs cannot be transferred. Since animals can carry or pass on worms and their eggs, we should also be careful to wash our hands after touching animals.

Take-Home Message

Hydatid disease is becoming more common across the world to the point that the WHO has identified it as a disease in need of more research. It is currently best treated using a combination of medicine and surgery, but more research will help to find out better techniques and details. It is best prevented by washing our hands before eating and after using the toilet or having contact with animals.