Echinococcus Flashcards
true or false: echinococcus is a zoonotic disease
-carnivore/herbivore->humans
adult echino parasitize the gi tract of what
carnivores aka they are the definitive host
for echino: larval stage, hydatid cyst, parasitize soft organs of what?
humans/herbivores/rodents which are intermediate hosts
what are the the 3 forms of echino larvaes that infect humans
-e multiocularis
-granulosus
-vogeli, oligarthrus
what are the characteristics of multiocularis
-alveolar in texture
-ulcerative
-hemorrhagic
-malignant
characteristics of granulosus
-uniocular
-benign
-25 cm
characteristics of vogeli, oligarthrus
-polycystic
-is in central and south america
life cycle of echino
-you eat the eggs
-oncosphere hatches, penetrates the intestinal wall, hydatid cyst in liver, lungs etc
-protoscolex from cyst
-scolex attaches to intestines
-adult in small intestine
-poop the eggs
the definitive host ingest what: cysts in organs or eggs in poop
cysts in organs
e multiocularis hosts
-cyst develops in rodents
-adults develop in foxes, dogs, wolves, coyotes or cats
what is the other name of echinococcus
flatworm
how many worms do heavily infected dogs have
1000
each tapeworm sheds how many eggs every2 weeks
1000
eggs of echino adhere to hairs aroun what
infected dogs anus, muzzle and paws
-contact also via soil, water, contaminated vegies, through flies or other arthropods
eggs of e granulosis are able to survive what
snow and freezing temps
-viable for 1 year in the pasture
eggs of echino are susceptible to what
desiccation
where are most of the echino cases
95% of all cases are in china
Adult and larval stages of Eg and Em are …..
morphologically
distinct; Em adult smaller
what are the characteristics of echico
-scolex(looks like t colum)
-neck
-3 segments: aka proglottids
what do the 3 segments contain
-a sac like uterus that contains up to 1000eggs
which parasites ova are similar
-e granulosus
-e multiocularis
-t solium
ova of echino survive to exposure of what
-householf disinfectants like lysol, 95% etoh or 20% formalin
reported cases of alveolar hydatid infection in the us through what
-farm cats probs aquired from wild rodents
Cystic Echinococcosis
- Cysts may grow 1-5 cm/year or persist without changes for years
- Cysts may spontaneously rupture or collapse or disappear
- Liver cysts appear to grow at lower rate than lung cysts
- Symptoms occur when cyst compresses or ruptures into
neighbouring structure
Alveolar Echinococcosis
- Initial asymptomatic period of 5-15 years – Chronic infection
- Primarily symptoms: jaundice (1/3 cases) and/or abdominal pain
- Fatigue, weight loss, Hepatomegaly
- High mortality rate in non-treated patients
what do uniocular hydatod contain
: hydatid fluid (1-3 liters; highly antigenic used in Casoni skin test), protoscolices, brood capsule and daughter cysts
cyst circumscribed by what in echino
a thick host fibrotic tissue infiltrated with chronic inflammatory cells
what do we know about the cyst survival mechanism unknown
lower cell mediated immunity
what is the size of uniocular hydatid
25cm
hydatid cyst of uniocular grows like what
-xenograph
-host is unable to control its growth or abrogate the infection/cyst
what is the appearance of alveolar hydatid cyst aka e multiocularis
histologically vesicular - gross appearance honeycomb or like
lung alveoli
what is the content of e multiocularis
Cyst content - pussy , unlike the unilocular cyst -no frank hydatid fluid
what is the growth like for e multiocularis
Growth by budding: germinal cells differentiate into bud-like structure- then
vesiculate; permeate surrounding host organ parenchyma
Human AHC usually
sterile aka no protoslice
Protoscolices present in
rodents aka suitable intermediate host
ALVEOLAR HYDATIDOSIS infection is …
chronic
cyst growth of ALVEOLAR HYDATIDOSIS
Cyst growth- progressive; apparently unchecked (as yet no reported cases of
self-cure)
primary lesion of alveolar hydatosis
hepatic aka tendency to metastasize
provisional diagnosis of a liver mass in alveolar hydatidosis
usually misdiagnosed as hepatic carcinoma
true or false: there are no effective chemo for alveolar hydatidosis
true
-case fatality rate 50-70%
-frequent cause of death: liver or kidney or liver failure
Factors determining the clinical course in unilocular hydatidosis
pressure atrophy and allergic
pressure atrophy deets
-by growing cyst
-hepatic (Right lobe ~ 85%)-upper right-quadrant pain, jaundice, cholangitis (pain),
– pulmonary (~ 90%; typical of Canadian strain of EG), chest pain, hemoptysis,
shortness of breath
– cerebral - seizure, increased intracranial pressure
– renal - hematuria, albuminuria, renal colic
– splenic - fragile cyst wall, polar growth to chest cavity
allergic hydatid thing
leakage of hydatid fluid
-skin hives and itching
-eosinophilia
-anaphilactic shock aka a serious complication
HYDATID DIAGNOSIS
Patients case history is helpful- particularly geographical origin
* Computed tomography/Magnetic Resonance Imagine scans, X-ray - detect space
occupying mass (congenital cyst; carcinoma; Eh liver abscess)-further confirmation by
serology or skin tests
* Serology (ELISA, IB, indirect hemagglutination test)
* Casoni skin test
what is the casoni skin test
– Type-1 hypersensitivity (skin reaction within 30 min)
– Type-4 – (CMI) positive (in case of a burnt-out cyst or post-surgical cases)
– Positive during the very early stages of infection
– negative in patients with active infection with high Ab titer - suggests specific
suppression of CMI
SUMMARY: HOST CONTROL MECHANISMS: hydatic disease
- EARLY RESPONSE: Primary control mechanisms- CMI and Antibody-dependent Cell
Cytotoxicity (ADCC) (IgG+MΦ, neutrophils, eosinophils). - Subsequently both these mechanisms are compromised-ADCC by circulating immune
complexes (IC): IC block Fc/C3b receptors; inflammatory cells engorge IC. - CHRONIC PHASE
- CMI is suppressed–reconstructed from humans and mouse models.
- Polarized Th2 response- high serum IgG, IgE and IL-10; marked reduction in Th1 cells
(disorganization of lymphoreticular tissues; induction of suppressor cells). - These events may explain the persistence of Hydatid cysts.
EARLY RESPONSE diagnosis hydatic
- EARLY RESPONSE: Primary control mechanisms- CMI and Antibody-dependent Cell
Cytotoxicity (ADCC) (IgG+MΦ, neutrophils, eosinophils). - Subsequently both these mechanisms are compromised-ADCC by circulating immune
complexes (IC): IC block Fc/C3b receptors; inflammatory cells engorge IC.
chronic phase hydatid diagnosis
CMI is suppressed–reconstructed from humans and mouse models.
* Polarized Th2 response- high serum IgG, IgE and IL-10; marked reduction in Th1 cells
(disorganization of lymphoreticular tissues; induction of suppressor cells).
* These events may explain the persistence of Hydatid cysts.
echino sylvatic hydatid disease affects what
wolf, caribou and moose all get the hydatid cyst but the adult wold also get the adult tape worm
Organ localization of E.g cyst:
~ 90%; pulmonary by the canadian Eg strain
– ~ 80%; rt hepatic lobe in the imported cases
Hydatid disease what is its form in north america
sylvatic
-present in first nations
infection of echino is due to what
accidental due to ingestion of eggs
clinical symptoms of echino take up until what
10-15yrs after infection
Chemotherapy in late stages: of echino
generally ineffective; treatment: surgical removal of E.g cyst-
–hepactomy in E.m
