Echinococcus granulosus

Echinococcus granulosus belongs to the tapeworms (Cestoda). They cause tissue infections such as hydatidosis and cystic echinococcosis. It is a small parasite (2-10 mm) transmitted alimentary. Since man is not the definitive host, the parasite does not remain in the digestive tract but travels through the host's body. Echinoccocus is cosmopolitan. 2-3 million people are infected each year.

Infectious agent: eggs in beast droppings (100-1500 pcs / proglottides / day), eggs are resistant to the external environment and are immediately infectious.

They cannot be morphologically distinguished from Taenia eggs!

Occurrence

 * Europe: highest incidence in sheep breeding areas.
 * Outside Europe: East Africa and South America, China.
 * No risk of infection: Iceland and Greenland.



Life cycle
Adults live in the gut of canines, which are the definitive hosts for parasites. Eggs come out of the body with dung. The intermediate hosts are herbivores and humans. After ingestion, an embryo is released from the egg in the digestive tract and penetrates the blood. Then the embryo travels through the body to any organ: the liver, lungs, brain, bones, skeletal muscle, kidneys, spleen, subcutaneous tissue. In that organ, it transforms into a slow-growing cyst, which can reach a size of 15 cm or more.

Clinical signs
Clinical symptoms are variable - depending on the location of the cysts, their size and the overall allergic reaction of the intermediate host. Cysts grow slowly and therefore the disease has an asymptomatic course for several years (up to about 5 cm). The symptoms appear at a time when the bulge, by its size, disrupts the function of the affected organ. The liver, lungs, brain, bone, kidneys are most often affected.

Symptoms by cyst location:


 * abdominal pain;
 * shortness of breath, chest pain, blood in sputum;
 * chronic cough, pneumothorax, pleurisy, pulmonary abscesses, parasitic pulmonary embolism;
 * neurological symptoms;
 * enlarged liver, jaundice, ascites;
 * gradual weight loss, while maintaining appetite.

If the cyst ruptures, the patient faces an allergic reaction, anaphylactic shock, and death.

After overcoming anaphylactic shock, daughter cysts may be disseminated and generalized echinococcosis may develop.

Diagnosis

 * Anamnesis, clinical symptoms, imaging methods
 * Serology - detection of antibodies
 * X-ray, sonography, CT - evidence of cysts

Therapy

 * Albendazol, mebendazalol – only parasitostatic effect
 * Surgical removal of cysts

Related articles

 * Echinococcus multilocularis
 * Hydatic disease

Literature



 * KOLÁŘOVÁ, Libuše. Alimentární infekce 2 [online]. [cit. 2012-02-20]. < http://tropy.lf1.cuni.cz/Data/files/TROPY/Prezentace_EN/echinococcus-2010-web.pdf >.


 * BEDNÁŘ, Marek, A SOUČEK a V FRAŇKOVÁ, et al. LÉKAŘSKÁ MIKROBIOLOGIE : Bakteriologie, virologie, parazitologie. 1. vydání. Brno : Triton, 1996. 560 s. ISBN 859-4-315-0528-0.