Echinococcus granulosus, Echinococcus multilocularis, and Echinococcus vogeli are tapeworms that can cause hydatid disease in humans. They have similar lifecycles involving canine hosts and intermediate hosts, but differ in morphology and pathogenicity. Diagnosis is often made through imaging that detects cysts, and serological tests. Treatment involves chemotherapy and surgery to remove cysts, while prevention focuses on deworming dogs in endemic areas.

1. TALK
KHEA G. MANZANILLA
Echinococcus granulosus

2. Echinococcus
granulosus,
Echinococcus
multilocularis,
Echinococcus vogeli
(Hydatid Cyst)

3. MORPHOLOGY
PATHOPHYSIOLOGY
LIFE CYCLE
SPECIMEN USE FOR IDENTIFICATION
DIAGNOSTIC FEATURES OF EACH STAGE
PREVENTION AND CONTROL TREATEMENT

4. These three species are all found as adult
worms in Canidae.
E. oligarthrus, whose status as a human parasite
is disputed, occurs as an adult in felids.
The life cycle of all these worms is similar to that
of E. granulosus
There is no unanimity as regards classification
of the genus Echinococcus
Echinococcus granulosus,
E. multilocularis, E. vogeli (hydatid
disease)

5. The adult worm is 0.6 cm or less in length and
possesses a scolex, neck, and usually three
proglottids.
One proglottid is immature, one is mature, and
one is gravid.
The eggs cannot be distinguished from those of
Taenia.
Eggs of Echinococcus contain an embryo, called
an onchosphere or hexacanth because of the six
hook-lets it bears.
Embryonated egg
GENERAL MORPHOLOGY
INFECTIVE STAGE

6. Symptoms of hydatid disease vary according to the location of the cyst.
Liver may cause no symptoms
Lungs are asymptomatic, if large enough give rise to cough, shortness of
breath, or pain in the chest
Bronchus may cause severe allergic symptoms and coughing
Secondary infection may lead to chronic lung abscess.
Central nervous system produce serious damage
Slow leakage of hydatid fluid sensitizes the patient and elicits
eosinophilia.
Bone development is abnormal and the limiting membrane is not formed.
Alveolar cysts usually occur in the liver
Growth into the vena cava or portal vein may lead to metastases, usually
to the lungs or brain.
PATHOPHYSIOLOGY

7. LIFE
CYCLE

8. LABORATORY DIAGNOSIS
FOR IDENTIFICATION OF E.
GRANULOSUS
Radiographic examination
Photoscans
Ultrasound and CT
aspiration of a portion of contents can be
per-formed, and examination of fluid
removed in this manner may reveal hydatid
sand

Serologic tests
Indirect hemagglutination test (IHA) and
enzyme-linked immunosorbent assay
(ELISA)
Serologic cross reactions

9. Echinococcosis may be diagnosed through
finding hydatid cysts with imaging techniques
such as CT scans.
The limiting membrane is thin in E. multilocularis,
and the germinal epithelium may bud externally,
to proliferate in any direction or even to
metastasize.
Unlike the unilocular hydatid cysts of E.
granulosus, there is little fluid in alveolar hydatids
of E. multilocularis which consist of many small
vesicles embedded in a dense connective tissue
stroma
DIAGNOSTIC STAGES

10. In E. vogeli infection, the germinal membrane of
the hydatid proliferates both inward, in the
original cyst, forming septa that divide it into
many sections and outward, to form new cysts.
The vesicles forming a polycystic hydatid are
relatively large and fluid filled.
In humans, hydatids of E. vogeli are found in the
liver, but also the lungs, pleura, pericardium, and
heart; the intercostal muscles and diaphragm; and
in the stomach, omentum, and mesenteries.
Having its adult stage in wild felids, E. oligarthus is
likewise characterized by the formation of
polycystic hydatid cysts in its rodent intermediate
hosts.
DIAGNOSTIC STAGES

11. ECHINOCOCCUS VOGELI: POLYCYSTIC
HYDATID CYST, HUMAN PERICARDIUM
ECHIN0COCCUS GRANULOSUS CYST
OF LIVER

12. CT SHOWS HYDATID CYST OF SPLEEN HYDATID CYST OF INVOLVING THE
UPPER HUMERUS OF A CHILD

13. Drug of choice: Mebendazole,
Albendazole, praziquantel, Ivermectin
Chemotherapy should be instituted a day
or so before surgery or aspiration
Surgical removal hydatid cysts,
percutaneous aspiration
PAIR (Percutaneous Aspiration, Injection
of hypertonic saline or other scolicidal
fluid-and Reaspiration)
TREATMENT

14. Where sheep and dog strains are
chiefly responsible for continuation
of the cycle, the most successful
control programs to date have
consisted of routine, 6 weekly
deworming of the dogs with
praziquantel.
PREVENTION