teaniea Flashcards
what are the factors of custicercosis
– 1. Poor sanitation, lack of latrines, inadequate fecal disposal facilities egg
ingestion & cysticercosis
– 2. Dietary habits -inadequate cooking of pork products containing cysticerci leads
to taeniasis
– 3. Open-air fecalism in rural areas - pigs consume human feces and over-time
build up a heavy load of cysticerci
– 4. Pigs deliberately placed in court yards to clean up human feces- same result as
open-air-fecalism
cysticercosis is primarily in what
rural disease
humans are what host of taenia
obligate definitive host for the afult tapeworm
adult tapeworms physical characteristics
-7m
-make 1000 proglottids each with 500 eggs
lil deets on scolex
Scolex ( 1mm) With suckers
and 2 rows of hooklets
true or false: proglottids are hermaphrodite
yeah
cestodes lack what
GI tract
adults cestode live where
in small intestine
Taenia tegument performs 3 functions:
- absorptive,
- excretory,
- digestive
Tegument metabolically active:
impermeable to peptide, protein & macromolecule but it acquires nutrients by active transport, pinocytosis, diffusion
Tegument microtriches /villi (~1um) - actively absorb….
amino acid, sugar, vitamin,
fatty acids
OVUM characteristics
~ spherical, ~45 um ; brownish shell, contain
oncosphere; egg hardy; survive for months in
moist soil.
ingestion of ova taenia causes
cyaticercosis
Hatched oncosphere/hexacanth embryo;
30 um in diameter; 6 hooks + a pair of secretory glands open laterally; both facilitate oncosphere mucosal invasion
3 modes of infection: of taenia
-egg ingestion: food/contaminated water
-autoinfection: finger to mouth
-reverse peristalsis of gut contents
what is reverse peristalsis of gut content
eggs and proglottids from the small intestine forced into the stomach- pepsin, pancreatic trypsin and bile salt facilitate egg hatching- can cause massive `cysticercosis
oncosphere anchors to what
intestinal mucosa, lyse enterocytes- enter blood vessels in lamina propria- enter portal circulation and peripheralize.
Surrounding host tissue most likely determines what in cysticercus
histogenetic fate of the
sequestered oncosphere :
what are the 2 histologic fates of cysterticus
- Cystic type of cysticercus develops in compact denser surroundings– muscle, sub-cutaneous tissues or brain parenchyma.
- Branched racemosus type cysticercus develops in open spaces: subarachnoid space or ventricles of the brain
neurocysticercosis where?
1.parenchymal
2.meningeal
3.ventricular
CYSTICERCUS LARVA: cystic type: oncosphere differenciates into
cystic form in dense tissues
Cysticercus blocks host attack
Taeniaestatin & polysulfated
polysaccharides; block inflammatory cell
signaling & complement activation
Intact tissue cysticerci induce
mild inflammation
Ruptured cyst of cysticercus larvae
® release antigensinduce intense tissue inflammation®
tissue lysis & edema; cause clinical
symptoms, particularly in
Neurocysticercosis (NCC)
PARENCHYMAL CYSTICERCOSIS: clinical symptoms depend on what
on the
number of cysticerci, their brain
location and viability:
in cysticercosis: a few parenchymal cysts may go
undetected or may cause
partial/segmental localized
paralysis- drugs (PZQ,
albendazole+corticosteroid)
in cysticercosis: Multiple parenchymal cystcompromise
CSF circulationincreased intracranial pressureNO treatment recommended
Racemosus type: ventricular/meningeal
Oncospheres differentiate into
racemosus forms into hollow locales -
subarachnoid space or brain ventricles
* racemosus type- 6-10 cm in size, lacks
scolex, grows like a bunch of grapes;
cyst fluid higly inflammatory
* Incurable when located at the base of
the brain
Non-Central Nervous System (CNS) cysticercosis
subcutaneous,
muscular etc: asymptomatic to mildly symptomatic
cns involvment cysticercosis:
chill to life threathening
Ventricular/meningeal racemosus cysticercosis:
you are fucked
in cysticercosis: Ruptured cyst-antigen release cause:
exaggerated inflammation and liquefaction
necrosis in surrounding tissues:
– meningitis, ventricular accumulation of CSF - cause intracranial hypertension
(hydrocephalus), seizure, blindness
Cysticercus at the base of brain- is generally
inoperable, with fatal
consequences within 5 years
Immunocytochemistry of the brain lesion show localized inflammation around
damaged cysts: in cysticercosis which cells
γδT cells, MΦ, eosinophils, neutrophils, NK cells, type 1 cytokines
diagnosis of cysticercosis
-combination of neuroimaging, serology and biopsy
-Computed tomography/magnetic resonance imaging:
– Detects space occupying lesions - cysticercosis included in the differential diagnosis along with tuberculoma, bacterial/fungal abscess/tumor
metastasis/congenital cysts
* Western blot, highly specific; a
10kDa recombinant cysticercus
antigen is in use in developing
countries to rule out other clinical
conditions.
C
Adult Taenia: small intestine; can live up to 2 yrs. what happens usually
– infection invariably subclinical; rare diarrhea or weight loss
– gravid segments found in feces/perianal area-signals infection
Ingestion of Taenia eggs by humans may lead to generalized or….
neurocysticercosis
T. solium Mexican strain- …..; Asian strain mostly sub-….
cyticercosis.
-neurogenic
-sub-cutaneous
treatment of cysticercosis
Cysticidal drugs: Praziquantel and Albendazole, mainly used against parenchymal cysts;
