Unraveling the Mystery of the "Hydatid Worm": Echinococcus granulosus Intrigued by parasites? Prepare to be captivated by the Echinococcus granulosus, a tiny tapeworm with a life cycle stranger than fiction. This microscopic menace may only reach a measly 3-6mm long, but its impact can be monumental. Imagine a parasite that thrives within the intestines of dogs, shedding eggs that lurk in the shadows of sheep pastures, waiting for their unsuspecting prey. When ingested, these eggs hatch and embark on a transformative journey, burrowing into the tissues of their new host, where they morph into fluid-filled cysts, aptly named hydatids. These cysts, like sinister bubbles, can silently grow for years, reaching the size of grapefruits or even basketballs! They can invade vital organs like the liver, lungs, and even the brain, posing a serious threat to human health. But the story of Echinococcus granulosus doesn't end there. This parasite holds secrets to the resilience of life and the complex web of relationships that bind us to the animal kingdom. Unraveling its mysteries could lead to revolutionary advancements in medicine and a deeper understanding of the delicate balance of our ecosystems. So, are you ready to delve into the world of the hydatid worm? Be prepared for a thrilling ride filled with unexpected twists, turns, and the potential for groundbreaking discoveries.

1. Name: Mahnoor Baig
Roll no: 181607

2. INTRODUCTION:
Echinococcus granulosus, also
called the hydatid worm, hyper
tape-worm or dog tapeworm
that dwells in the small
intestine of canids (dogs) as an
adult, but which has
important intermediate hosts
such as livestock and humans,
where it causes cystic
echinococcosis, also known as
hydatid disease.

3. The adult tapeworm
ranges
in length from 3 mm to
6 mm
and has three proglottids
("segments") when intact
 immature proglottid
 mature proglottid
 gravid proglottid.
The average number of
eggs
per gravid proglottid is
823.

4. No of Hosts- 2
 Definitive host- Dogs
 Intermediate host- Man or
sheep etc.
Definitive host
Intermediate host

5. LIFE CYCLE OF ECHINOCOCCUS GRANULOSUS:
1. Echinococcus granulosus is ingested and attaches to
the mucosa of the intestines in the definitive host
(dog) and there the parasite will grow into the adult
stages.
2. Gravid proglottids release eggs that are passed in
the feces, and are immediately infectious
3. After ingestion by a suitable intermediate host, eggs
hatch in the small intestine and release six-hooked
oncospheres.
4. Onchospheres that penetrate the intestinal wall and
migrate through the circulatory system into various
organs, especially the liver and lungs.

6. 5. In these organs, the oncosphere develops into a thick-
walled hydatid cyst that enlarges gradually, producing
protoscolices and daughter cysts that fill the cyst
interior.
6. The definitive host becomes infected by ingesting the
cyst-containing organs of the infected intermediate
host.
7. After ingestion, the protoscolices evaginate, attach to
the intestinal mucosa , and develop into adult
stages in 32 to 80 days.
The life cycle then continues in humans:
 Humans can become infected if they ingest
substances infected with Echinococcus eggs.
The eggs then release oncospheres in the small
intestine.

7.  Humans are aberrant intermediate hosts,
and become infected by ingesting eggs .
 At these places, oncospheres migrate
through the circulatory system and
produce hydatid cysts.
 If cysts rupture, the liberated
protoscolices may create secondary cysts
in other sites within the body (secondary
echinococcosis).

9. HYDATID CYST
CYST TO ADULT