The document discusses the etiology and epidemiology of Echinococcus granulosus, a cestode responsible for hydatidosis, with dogs as final hosts and various ruminants, humans, and primates as intermediate hosts. It highlights the clinical findings, diagnosis methods, and the lack of symptoms in infected ruminants, while noting potential respiratory distress in humans. Control measures include treating dogs, restricting access to abattoirs, and the development of a recombinant vaccine requiring further refinement.

1. By,
Dr Ranjini Manuel

2. ETIOLOGY
 Echinococcus granulosus
 Class : Cestoda, Family : Taeniidae
 Common Name : Dwarf tapeworm of dog, Hydatidosis
 Final host : Dog and wild canids
 Intermediate host : Domestic and wild ruminants, man , primates, pigs
 Horses and donkeys are resistant
 Echinococcus – 6mm long – Consist of scolex and 3-4 segments- terminal –gravid
 Hydatid Cyst : large fluid-filled vesicles, 5-10cm diameter, concentrically laminated cuticle
and germinal layer.

4. EPIDEMIOLOGY

6. LIFE CYCLE AND PATHOGENESIS

8. Clinical findings
 Cysts are more commonly found in the liver and lungs in sheep and goats, although they can
develop at any organs (Varma and Ahluwalia 1990; Godara et al., 2014).
 The adult worms remain alive for a longer period in the definitive host whereas the cysts may
remain viable for the life span of the intermediate hosts (Godara et al., 2014).
 The occurrence of the hydatid cyst in older age could be attributed slow rate of development of cyst
which could take several months. Thus, hydatid cyst are detected in older animals. ;(Godara et al.,
2014).
 NO clinical signs are associated with these lesions in ruminants
 Human infection can result –respiratory distress & abdominal enlargement
https://www.researchgate.net/publication/322928330_Occurrence_of_Hydatidosis_in_small_ruminants

9. NECROPSY FINDINGS
HYDATID CYST IN LUNGS

10. HYDATID CYST IN LIVER

11. DIAGNOSIS
 Ruminants- EITB, necropsy finings, radiography (Pedro, et al.,1999)
 Canine – microscopic stool examination, Coproantigen detection enzyme
immunoassay (EIA)
 Humans- ultrasonography, x-ray examination , Enzyme linked immunoelectro
transfer blot (EITB) assay
Radiograph of liver
with hydatid cysts

12. remarks
 Evn if we ingest the vesicular fluid we wont infected – infective stage is the egg
with embryo . Highly protein rich fluid . Evn if scolices are ingested
 Sterile and non sterile fluid
 Cassoni test ?

13. CONTROL
• Regular treatment of dogs to eliminate adult
tapeworms
• Denying dogs access to abattoirs
• Proper disposal of infected carcass
• It can be transmitted from dogs to humans easily
through contact – careful measures should be
taken while handling them
• Recombinant DNA vaccine has been developed
for Echinococcus granulosus, but needs
refinement for practical application- not available
commercially