Week 7 Flashcards
Cestodes of Importance
Characteristics of Echinococcus spp.
* proglottids instead of eggs
General Echinococcus life cycle
What eggs look exactly like Echinococcus?
Taenia eggs
Echinococcosis vs. cystic or alveolar echinococcosis or hyatid disease
Echinococcosis refers to tapeworms in the canid DH
* cystic (unilocular) or alveolar (multilocular) echinococcosis or hyatidid disease (IH- various)
Species? IH? Metacestode? Predilication site? Geographic distribution?
Unilocular hydatid cysts (echinococcus)
WHat happens within hytadid cyst?
Asexual reproduction
What is this? Differences to the other?
Multilocular (Alveolar) hyatid Cysts
No cyst wall, gelatinous matrix
* invade tissue, including blood vessels- enter blood stream and metastasize to different organ systems- act like a tumour
* undergo external budding instead of internal budding like unilocular cysts
Distribution of E. multilocularis
Distribution of E. granulosus
What are the different E. granulosus “genotypes?”
Epi in mainland Australia of E. granulosus
What is the PPP?
5-6 weeks is PPP
What life cycle does this picture remind you of?
E. granulosus
Public health and E. granulosus
* E. granulosus only species to become endemic within Australia
* had a lot to do with educating on life cycle- don’t feed offal (refers to the internal organs and entrails of a butchered anima) to domestic animals
* introduced with sheep/ dogs during European colonization in early 1800s
* Starting again because people have forgotten
* Adapted well- native and feral wilfe-life into its cycle
* Eradicated from Tasmania in 1996 – no sylvatic cycle– because they don’t have feral dogs or wild dogs– but it still took them 30 years
Is hydatid disease in Australia a notifiable disease?
Age of majority of cases? When were they exposed?
What percentage of farm dogs in NSW and Vic are infected with E. granulosus? What about feral dogs in SE QLD?
No- they have taken it off
Majority of cases 30-40
* exposed when they were young
* 18-29% infected farm dogs
40% in feral dogs in SE QLD
Sources of infection of E. granulosus
One of the main reason not to kiss dogs, especially farm dogs. Eggs are sticky - they lick their bums.
Why isn’t Toxocara that has just been passed a problem? Vs. eggs from echinococcus is a problem when just passed?
With toxocara eggs, they aren’t embryonated for at least 2 weeks. But with echinococcus when they rupture from the proglottis- they are infective immediately and very sticky.
Significance of E. granulosus
No clinical signs!! But the animal/ human would have cysts on lungs and liver.
Significance to humans of E. granulosus
** your body may wall off and calcify the cyst
* space occupying lesion
* if it is impinging on the bile duct–> jaundice
* in the brain–> epilepsy
Diagnosis of E. granulosus in humans
** can also drain cyst but you really need surgery to truly treat
Prevention and Control of E. granulosus
How do humans get hytadid cysts?
* humans get it from their dogs
* you cannot get it from the hytadid cyst fluid
* Anthelmintic treatment for dogs- in endemic areas, dogs should be treated with praziquantel q 4-6 weeks
* follow by deep burial or burning of dog faeces post treatment because massive potential for infection due to passed proglottids
* vaccine for sheep- E. granulosus
How did Tasi eradicate E. granulosus?
Rounded up dogs and treating dogs with a drug called arecoline- causes massive paralysis of worms. Because before praziquantel. Dogs would sometimes poo out guts as well and puppies sometimes died.
Picked up poo and using a flame thrower for whatever else is left on the grass (because a thousand worms would be left behind)
LIfe cycle of E. multilocularis
E. multilocularis
* necropsy- intestines frozen for -20C for weeks!! And some may still be infective
Distinguishing E. granulosus vs. E. multilocularis
Diagnosis with faecal sample E. multilocularis
What are the three main classes of drugs for trematodes and cestodes?
- Praziquantel
- Salicylanilides
- Benzimidazoles
When do you give Praziquantel?
What would you use Salicylanilides?
When would you use Benzimidazoles?
Fasciola! Moneizia, larval tapeworms
