STRONA G£”WNA » Subject 9 (Labours, 1st year DDS)

Wydzia≥ Lekarski
MD (6-year)
DDS (5-year)
Pharmacy (6-year M.Sc.)


Subject 9 (Labours, 1st year DDS)

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Hymenolepis nana

Kind of parasite: homoxenous and monoxenous.

Definitive host(s): human.

Intermediate host(s): human.

Infective stage: egg.

Transmission by ingestion eggs of the parasite.

Site of infection: the small intestine and villi.

Diagnostic method(s): microscopic identification of eggs in stool;

Geographical distribution: cosmopolitan.
the gravid proglottids often rupture within the intestine and infestive eggs may pass in the feaces or liberated oncospheres may repeat the cyclic development (hyperinfection);
autoinfection and endoautoinfection in human’s organism may occur;
prevention consist in treatment of infected individuals and proper personal hygiene.

Echinococcus spp.

Two species from Echinococcus genus were described during the lab No. 7: E. granulosus and E. multilocularis.

Kind of parasite: heteroxenous and polyxenous.

Definitive host(s): all carnivorous; the main definitive host for E. granulosus is dog whereas for E. multilocularis are wolfs and foxes.

Intermediate host(s): herbivorous and omnivorous mammals, and rodents; human is accidental host.

Infective stage: eggs or gravid proglottids with the eggs.

Transmission: by ingestion of the eggs of parasites (unsatisfactory level of personal hygiene).
Site of infection: to the most common sites of infection belong: liver, lungs and brain.

Diagnostic method(s):
immunological tests;
radiological, USG and CT examination;
fine-needle biopsy of the hydatid cyst and examination of the hydatid cyst content for the presence of numerous protoscolices (hydatid sand).

Geographical distribution:
E. granulosus – cosmopolitan;
E. multilocularis – Europe, Asia, North and South America and New Zealand.
E. granulosus - the incidence of human hydatid disease (i.e. the occurrence of hydatid cysts) depends on the association of man with infected dogs. Hydatidosis constitutes a very serious medical problems in sheep- or cattle raising areas. Humans are infected when they ingest eggs, usually as a result of contact with dogs (which are not under the veterinary service). The parasite circulates between domestic animals (domestic cycle) and wild animals (sylvatic cycle).
E. multilocularis – this tapeworm causes alveolar hydatid disease in humans. The tapeworm circulates among wild animals but the rodents are responsible for transmission of parasite into domestic cycle.

 Author: Piotr Nowosad date: 2020-05-12  print    back  
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