E. Granulosus cestodiasis
Echinococcus granulosus belongs to the class of cestodes, and the family of taeniids. Cestodes are obligate parasite hermaphrodite worms, whose segmented body doesn’t possess any digestive tract. Ovigerous segments of taeniids are (plus longs que larges). E. Granulosus is a very little tapeworm whose (longueur) (varie de) 4 (à) 6 mm. Its last segment is greater than half the total length of its body. The number of adult worms in a dog’s digestive tract can (atteindre) 150,000. The ovigerous segments, which are rejected in faeces, are almost invisible to the naked eye (they are (environ) 2-3mm long). Many species of mammals can be intermediate hosts , man comprised, although most frequently the sheep is affected. The embryos use the blood stream to reach the liver or the lungs, and to form there a larva that is also called hydatid cyst. It is spherical, its (moyen) diameter being of a few centimetres, although in very rare cases its volume can rise to several litres.
Adult worms can live (légèrement) more than 10 years in the digestive tract of a dog. Eggs are very resistant in the environment and can resist more than a year in temperatures ranging from –5 30°C, as far as hygrometry is sufficient. However, their survival is low in (profonde) water. Infestation occurs by the oral route by ingesting food or water soiled by canine excrement, or less often by transplacental route.
Echinococcus cestodiasis is a dangerous (zoonose), therefore special attention must be paid to basic hygiene. Moreover, carefulness is recommended when treating an infested dog, this provoking the rejection of numerous eggs in the environment. |