Transcript The significance of Medical Parasitology

Platyhelminths : Cestodes
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Pseudophyllidea
• Diphyllobothrium latum (pernicious anemia)
• Cyclophyllidea
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Taenia solium (pork tapeworm)
Taenia saginata (beef tapeworm)
Echinococcus granulosus (cystic, CE)
Echinococcus multilocularis (alveolar, AE)
A rare and
emerging disease
Macroparasite example 2 :
Taenia solium : Disease
Neurocysticercosis
Cestode. Unique zoonosis.
Under-reported disease.
Diagnostic difficulties.
Lack of epidemiological
data.
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Unique zoonosis :
Human only known
definitive host, pig
intermediate host
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Humans carry both
adult worms in the
intestine & larval
cysticercosis in the
muscle & other
tissues
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Infection with adult
worm in humans
dangerous to host &
other contacts
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Under-reported
disease
Biology of
Taenia solium
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Primarily due to
pressure effects of a
space-occupying cyst
or lesion in an organ
or tissue
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CNS involvement :
Neurocysticercosis
(NCC) : pathology
relates to number,
size, type (cellulose
or racemose),
condition & site of
cysticerci in the brain
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Active versus inactive
NCC
Symptomatology
and pathology 1
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Active NCC :
arachnoiditis (spinal
fluid pleocytosis,
increased CSF
protein, positive CSF
serologic test)
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Small number of
patients : obstructive
hydrocephalus,
cranial nerve
involvement,
intercranial
hypertension, arterial
thrombosis & stroke
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Epilepsy, dementia,
meningitis
Symptomatology
and Pathology 2
Intraocular cysts :
visual impairment
Location of parasites in
2188 cases of cysticercosis
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CNS
82%
Eye
17%
Subcutaneous
tissue
7%
Muscle
5%
Other organs 6%
Generalized 1%
Flisser & Craig, 2005
Adult worms
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Stool analysis :
uterine branch
structure or scolex
morphology after
treatment
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Molecular
differentiation of
adult worms
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Capture ELISA for
coproantigen
detection
Diagnosis 1
Cysticercosis
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Imaging methods
(CT scan useful
for brain &
calcified cysts ;
MRI not but
excellent for
detecting active
cysts in soft
tissue)
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Serology (ELISA
versus
Immunoblot)
Diagnosis 2
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Retrospective case
finding
• fixed time period,
annual incidence
rate per 100,000
population
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Active screening
• Mass radiological
imaging surveys
• Immunodiagnostic
surveys
• Autopsy surveys
Epidemiology :
cysticercosis
Cysticercosis in communities
• Endemic focus: Rural Latin America
• Major risk factor: current or past case
of intestinal Taenia in the household
• Non-endemic community: New York
City
• Significant number of human
cysticercosis cases in an Orthodox
Jewish community
Treatment : cysticercosis
Until recently symptomatic patients :
anticonvulsants, corticosteroids, surgery
• Chemotherapy
• CT useful for monitoring
• Active parenchymal brain cysts and
subarachnoid (racemose) cysts :
albendazole
• Albendazole also effective against
ocular cysticercosis
• Alternative drug : praziquantel less
effective
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Freezing and
appropriate cooking
of pork
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Identification and
treatment of Taenia
carriers (mass
treatment ?)
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Improved health
education, prevention
of vegetables
irrigated with
contaminated water
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Confinement of pigs
Porcine vaccine
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Control :
Taenia solium