Echinococcus multilocularis - Alveolar cyst

Question 1

What are the definitive hosts (FH) for Echinococcus multilocularis?

Answer 1

Fox, wolf, dog, cat

Question 2

What are the intermediate hosts (IH) for Echinococcus multilocularis?

Answer 2

Rodents, small insect-eating mammals, man

Humans can act as accidental intermediate hosts.

Question 3

Describe the life cycle of Echinococcus multilocularis.

Answer 3

1. Gravid proglottids release eggs that are passed in feces. They are immediately infectious.
2. IH ingest eggs, which hatch in the SI and release a six-hooked oncosphere that penetrates the intestinal wall and migrate through the circulatory system into various organs – especially liver. Develops into a alveolar cyst.
3. It enlarges gradually, producing protoscolices and daughter cysts.
4. FH gets infected by ingesting the cyst-containing organs in the IH.
5. After ingestion, the protoscolices evaginate and attach to the intestinal mucosa – Develops into adult (takes 32-80 days).
6. Humans are accidental IH, becomes infected by ingesting eggs. Released into the intestine, the alveolar cyst develops in liver. Metastasis or dissemination to other organs (lungs, brain, heart, bone) may occur if the protoscolices are released from cysts, sometimes called secondary echinococcosis.

Question 4

What is the role of humans in the life cycle of Echinococcus multilocularis?

Answer 4

Humans are accidental IH and become infected by ingesting eggs, leading to the development of alveolar cysts in the liver.

This can lead to metastasis to other organs such as lungs, brain, heart, and bone.

Question 5

What are the clinical signs of alveococcosis?

Answer 5

Abdominal pain, biliary obstruction, occasionally metastatic lesions in lungs and brain

Question 6

Pathogenesis of Echinococcus multilocularis

Answer 6

IH: affects liver as a slow-growing tumor

Question 7

What control measures can be taken to prevent Echinococcus multilocularis infection?

Answer 7

Prevention by Praziquantel for dogs, vaccination, health education

Question 8

What diagnostic techniques are used for alveococcosis?

Answer 8

Post-mortem findings (Intestinal Scraping Technique), SCT (Sedimentation and Counting Technique)

Question 9

Location of Echinococcus multilocularis:

Answer 9

IH: liver (brain, lung)
FH: SI

Question 10

Morphology of Echinococcus multilocularis

Answer 10

2-4mm, scolex with 4 suckers, rostellum with 2 rows of 28-50 hooks, neck, 3-5 proglottids

Question 11

What is the causative agent of alveococcosis?

Answer 11

Echinococcus multilocularis

Alveolar echinococcosis is primarily found in the Northern hemisphere, including central Asia, North Russia, Japan, and parts of North America.

Question 12

Tx of Echinococcus multilocularis

Answer 12

Praziquantel, surgical removal

Question 13

Metacestode of Echinococcus multilocularis

Answer 13

Alveolar cyst