Difference between revisions of "Echinococcus multilocularis"

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[[Image:Rat infected with E. multilocularis.jpg|thumb|right|150px|Rat infected with ''E.  multilocularis'' - Dr. I. Kagan]]
  
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{| cellpadding="8" cellspacing="0" border="1"
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| Causative agent of:
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| Alveolar Hydatid Disaese
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== Alveolar Hydatid Disease (''E. multilocularis'') ==
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==Overview==
[[Image:Rat infected with E. multilocularis.jpg|thumb|right|150px|Rat infected with ''E. multilocularis'' - Dr. I. Kagan]]
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''E. multiocularis'' is not present in the UK but is endemic in central Europe and North America. It is zoonotic and so presents a major health problem in Europe (including Switzerland where urabn foxes are now infected) haveing spread from 4 countries in the 1980s to being found in 12 countries now. This has been attributed to the anti-rabies campaign which has increased the number of foxes which are commonly found as the definitive host. Humans can act as intermediate hosts if eggs are ingested causing the formation of hydatid cysts in the liver, these rapidly invade the liver and are inoperable.
This parasite does not occur in the UK. It is largely restricted to forest areas of central Europe (including Switzerland where urban foxes are also infected) and North America. It is a significant public health problem and is spreading across Europe, where 12 countries are now affected compared with four in the 1980’s. The metacestode is the alveolar (or multilocular) cyst. Human infections are particularly dangerous as daughter cysts bud off externally as well as internally from the germinal layer so that the cyst rapidly infiltrates the liver like an invasive tumour, and is inoperable. Dogs, and to a lesser extent cats, can become infected with the adult tapeworm, but the main epidemiological cycle involves the fox as the final host and microtine rodents (particularly voles) as intermediate hosts. The latter have a very short life-span – hence the rapid growth-rate of the alveolar cyst in intermediate hosts, including humans. The anti-rabies campaign in Europe has led to a large increase in the number of foxes and, consequently, of infected rodents.
 
  
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==Characteristics==
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Scolex
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*2 rows of hooks
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Proglottid
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*Terminal proglottid forms 1/2 the length of the mature worm
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*1 proglotted shed per week
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*Has single genital pore
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Eggs
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*Striated shell
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*Hooks visible on oncosphere
  
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==Life Cylce==
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''E. multliocularis'' has a typical cestode life cycle involving the formation of a metacestode cyst in the intermediate host before developing to adulthood in the definitive host. The definitive host for ''E. multliocularis'' is most commonly the dog, though it has also been seen in the cat. Epedimiologically the most important definitive host in the spread of the disease is the fox. ''E. multliocularis'' mainly uses small rodents such as voles, mice and rats as an intermediate host, forming multilobular hydatis cysts in the liver of the host. The sahort life span of the intermediate host species is the reason for the rapid growth of the cyst, even in longer lived host like humans. This is the stage that generally causes pathology in the host animal and can be fatal.
  
  
''Echinococcus granulosus'' in [[Peritoneal Cavity - Parasitic Pathology|Peritoneal Cavity Parasitic]] and [[Muscles Inflammatory - Pathology#Cestodes|muscles]]
 
*''Echinococcus granulosus'' in hydatid disease of [[Respiratory Parasitic Infections - Pathology#Hydatid cysts|lungs]]
 
 
[[Category:Taeniidae]]
 
[[Category:Taeniidae]]
 
[[Category:To_Do_-_NickJ]]
 
[[Category:To_Do_-_NickJ]]

Revision as of 10:04, 9 July 2010



Rat infected with E. multilocularis - Dr. I. Kagan
Causative agent of: Alveolar Hydatid Disaese


Overview

E. multiocularis is not present in the UK but is endemic in central Europe and North America. It is zoonotic and so presents a major health problem in Europe (including Switzerland where urabn foxes are now infected) haveing spread from 4 countries in the 1980s to being found in 12 countries now. This has been attributed to the anti-rabies campaign which has increased the number of foxes which are commonly found as the definitive host. Humans can act as intermediate hosts if eggs are ingested causing the formation of hydatid cysts in the liver, these rapidly invade the liver and are inoperable.

Characteristics

Scolex

  • 2 rows of hooks

Proglottid

  • Terminal proglottid forms 1/2 the length of the mature worm
  • 1 proglotted shed per week
  • Has single genital pore

Eggs

  • Striated shell
  • Hooks visible on oncosphere

Life Cylce

E. multliocularis has a typical cestode life cycle involving the formation of a metacestode cyst in the intermediate host before developing to adulthood in the definitive host. The definitive host for E. multliocularis is most commonly the dog, though it has also been seen in the cat. Epedimiologically the most important definitive host in the spread of the disease is the fox. E. multliocularis mainly uses small rodents such as voles, mice and rats as an intermediate host, forming multilobular hydatis cysts in the liver of the host. The sahort life span of the intermediate host species is the reason for the rapid growth of the cyst, even in longer lived host like humans. This is the stage that generally causes pathology in the host animal and can be fatal.