Echinococcus Granulosus (Hydatid Disease)

What Sample is needed for Echinococcus Granulosus?

1. A Haemagglutination test is done on the serum.
2. Hydatid cyst fluid for the examination.
3. The other specimens may be sputum, urine, liver, and spleen.

What are the Indications for Echinococcus Granulosus?

• This test is done to diagnose a parasitic disease caused by Echinococcus granulosus.

How will you describe the Biology of Echinococcus Granulosus?

1. The genus Echinococcus contains three species:
   1. Echinococcus granulosus.
   2. Echinococcus multilocularis.
   3. Echinococcus vogeli.
2. Humans are hosts in the larval stage or hydatid.
3. The genus Echinococcus has the smallest tapeworm in the Taeniidae.
   1. The adult worm measures 0.6 cm or less in length.
4. This is found in areas where there are sheep (herbivorous).
5. These are in close contact with the dogs and other canines.
   1. Other regions are where canines and humans have close contact.

How will you describe the Lifecycle of Echinococcus Granulosus?

1. E. granulosus is a parasitic disease caused by a tapeworm of the genus Echinococcus.
2. This is also called Hydatid cyst disease and Hydatid cyst.

What are the features of the adult worm?

1. It is 0.6 cm (3 to 8mm) or less in length.
2. It consists of the following:
   1. Scolex.
   2. Neck.
3. Proglottids are 3 in number (the segment containing sex organs) and are:
   1. One anterior-most is immature.
   2. One is middle and is mature.
   3. One is terminal and is gravid.

Echinococcus Granulosus: Echinococcus adult shape

What are the hosts for the spread of Echinococcus Granulosis?

1. Definitive host:
2. E. granulosus requires two mammalian hosts (animal likess dogs, sheep, horses, goats, pigs, and cattle) to complete their life cycle.
   1. It uses dogs or other canines as a definitive host.
      1. The dogs are the definitive host.
      2. Sheep and cattle are intermediate hosts.
      3. Infection is commonest in sheep and cattle-raising areas.
   2. Habitat is a small intestine.

Echinococcus host

3. Intermediate host:
4. Herbivorous is an intermediate host that becomes infected by eating the contaminated herbage.

Echinococcus life cycle

Echinococcus life cycle

5. Segments containing eggs (gravid proglottids) or free eggs are passed in the feces of the definitive host, a carnivore.
6. The eggs are ingested by an intermediate host (maybe humans), in which the metacestode stage and protoscoleces develop.

Hydatid cyst life cycle

7. Then, the cycle is completed if a suitable carnivore eats the metacestode and protoscoleces.
8. Hydatid cyst (Hydatidosis) develops in various organs. The liver and lungs are the most common sites. Still, it can be seen on any other site; even these cysts are reported in the eye, brain, kidney, spleen, muscles, and bones.
9. Hydatid cyst in the early stages is out of the thick laminated membrane and lined by thin germinal epithelium; its size, in the beginning, is 1 cm in diameter.
10. In the end, the older hydatid cyst contains free protoscolices, a daughter cyst, and an amorphous material, and all these are called hydatid sand.

Hydatid cyst formation

Hydatid cyst formation

How will you describe the Summary of the life cycle of Echinococcus granulosus (Hydatid cyst)?

1. Humans ingest eggs from sheep and dogs.
2. These eggs will hatch in the intestine and form larvae.
3. The larva penetrates the wall of the intestine and enters the blood circulation.
4. The majority settle in the liver, and a few go to the brain, lungs, and kidneys.

Hydatid cyst liver

5. Rarely are these found in unexpected places like the eye, vagina, etc.
6. These larvae form the hydatid cyst, which has fluid in the center. There is the formation of daughter hydatid cysts and protoscolices in the cysts.
   1. The size may reach 5 to 10 cm.
   2. This multilocular cyst is called Echinococcus multilocularis.
   3. 10% of the cysts cause symptoms and are difficult to treat.
   4. If the cyst fluid leaks out, it causes a fatal allergic reaction.

Echinococcus Granulosus: Summary of the life cycle of Echinococcus Granulosus

What is the Epidemiology of Echinococcus Granulosus?

1. This disease is present throughout the world.
2. Children are more likely to get an infection due to poor hygienic habits.
3. Human infection occurs accidentally through the feces of infected dogs or other herbivores.
4. These prevail in sheep-raising areas like New Zealand and Australia.
5. This disease is quite common in the South American continent.
6. It is seen in Alaska, Canada, and the nearby United States in North America.

What are the Signs and Symptoms of Echinococcus Granulosus?

1. 10% of the cysts cause signs and symptoms.
2. This depends upon the size and location of the hydatid cyst.
3. The patients are asymptomatic; the incubation period may be in years when the cyst appears and is clinically diagnosed.
4. There are nonspecific symptoms of:
   1. Nausea.
   2. Weight loss.
   3. Weakness.
5. Other symptoms are due to the pressure of these cysts.
6. In the case of the liver cyst:
   1. The patient may have abdominal pain.
   2. Nausea and vomiting.
   3. There may be obstructive jaundice.
7. In the case of the lung:
   1. There will be a chronic cough.
   2. Chest pain and shortness of breath.
8. Rupture of the cyst naturally or by taking the sample may lead to anaphylactic shock.
9. Summary of signs and symptoms:
   1. Asymptomatic infection.
   2. Hepatomegaly.
   3. Cough.
   4. Pressure on different organs.
   5. Rupture of the cyst may cause allergic reactions like anaphylactic reactions.

How will you Diagnose Echinococcus Granulosus?

1. A complete blood picture may show eosinophilia.
2. Haemagglutination test with significant titer above 1:100.
   1. Indirect hemagglutination and ELISA are also satisfactory tests.
   2. Serological tests are more specific than the traditional Casoni test.
3. Direct microscopic examination for ova and parasites.
   1. Microscopy of hydatid cyst fluid shows scolices, daughter cysts, brood capsules, or hydatid sand.
4. X-rays may show cysts in asymptomatic patients. The cyst shows a sharp outline and may see fluid levels.
5. Bone marrow biopsy.
6. CT scan or ultrasonography helps find a hydatid cyst.

How will you treat the Echinococcus Granulosus?

1. Surgical removal of the operable cyst. This is the best choice of treatment.
2. In the case of inoperable cases, can give:
   1. Mebendazole.
   2. Albendazole.
   3. Praziquantel.
3. The first drug, Mebendazole, was found to be effective.
4. Albendazole is given for a longer time to kill the cyst. This was better absorbed and penetrated the cyst wall. Now, this drug is preferred to mebendazole.
5. Albendazole is given as 10 mg/Kg body weight or 400 mg twice daily for 4 weeks.
   1. This cycle can be repeated at 2-week intervals. You can give such 12 cycles of Albendazole drugs.
   2. Response to therapy can be judged by ultrasound or MRI and may be repeated at intervals of 3 months.
6. Percutaneous injection of hypertonic saline  (solicidal agents) and aspiration is sometimes considered safe and effective therapy.
7. Praziquantel is protoscilocidal drug. It has a very good result when given with Albendazole.
8. Can inject saline, iodophor, and alcohol to ensure that the cystic contents are dead.
   1. After 30 minutes, it can be enucleated from the cyst.

How will you Prevent Echinococcus Granulosus?

1. Improve the hygiene of people handling the dogs.
2. Frequently treat the dogs in endemic areas.
3. Improve the ways for the disposal of the dog’s feces.
4. 6 weekly deworming of the dogs with praziquantel is very effective.

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