BLOOD FLUKES Flashcards
Species which inhabit the portal
bloodstream of vertebrates
(Blood Flukes)
Oriental blood fluke
Schistosoma japonicum
Visceral blood fluke
Schistosoma haematobium:
Manson’s blood fluke
Schistosoma mansoni:
___________ are dioecous (individuals of
separate sexes)
Schistosoma spp.
___________is more frequently found in the
________________draining the
small intestine
S. japonicum
SUPERIOR MESENTERIC VEINS
_____________occurs more often in the _________________ draining the large
intestine
S. Mansinoni
INFERIOR
MESENTERIC VEINS
_______________most often inhabits in the
____________, but it can also be found in the
RECTAL VENULES
S. haematobium
VESICULAR AND PELVIC VENOUS PLEXUS OF
THE BLADDER
______________also inhabit
the INFERIOR MESENTERIC PLEXUS but lower
in the bowel than S. mansoni.
S. intercalatum and S. guineensis
The eggs are moved progressively toward the
lumen of the intestine
and of the bladder
and ureters (__________), and are
eliminated with feces or urine, respectively.
(S. mansoni,
S.japonicum,
S. mekongi,
S. intercalatum/guineensis)
S. haematobium
Parasitizes portal vein
and its branches
Schistosoma japonicum
Each female fluke
deposits _______
immature eggs/day
500-2000
Each female fluke
deposits _______
immature eggs/day
500-2000
Adult worms are 10 to 20 mm long
schistosomes have separate sexes
the male has a canal in which the slender worms enter
Schistosoma Japonicum
Males have a
gynecophoral canal
which receives the
female during
copulation
Schistosoma
japonicum in
eternal copula
Ova
Ovoidal, rounded or
pear-shaped
Thin shell
Pale yellow
Curved hook / spine
or lateral knob
Laid in the
multicellular stage
and embryonate
within _________
Schistosoma japonicum
10-12 days
Hatches from the egg in
slightly alkaline clean
water with a temp.
between __________
Free swimming ciliated
embryo liberated from
the egg
Phototactic
Infect snails
Miracidium
Schistosome Miracidium
25 0C to 310C
______________
develop from miracidium within
the snail
Mother
sporocysts
___________ develops from
mother sporocyst
Daughter
sporocyst
___________ develop from daughter
sporocyst
Cercariae
Emerges from
daughter sporocysts
Escapes from the snail
Has a body and a
bifurcate tail
Infects man by skin
penetration
Cercaria
Develops from cercaria after skin
penetration
Adapted to survive in serum or
physiologic saline at _______
Enter the pleural cavity—diaphragm—
peritoneal space—penetrate the liver to
reach the intrahepatic portions of the
portal vein
Schistosomulae
37 0C
______nside the
gynecophoral canal
of male
female
▪ Ova
With Lateral spine
Schistosoma mansoni
terminal spine Eliminated with urine
Schistosoma haematobium
___________is one of the symptoms of schistosomiasis
Distended belly
-a pruritic papular
rash that develops 24
hrs after exposure)
Cercarial
Dermatitis/
Swimmer’s Itch -
local cutaneous
hypersensitivity
Evasive Stage
-cough, fever,
asthma-like
symptoms and
may have
lymphadenopathy ,
hepatic, and splenic
enlargement due to
the migration of the
worms through the
circulation (occurs 5-
10 weeks after
infection)
Katayama fever -
systemic
hypersensitivity
Acute Stage
Gastrointestinal
involvement in which
more and more eggs
enter the portal
circulation, resulting
to enlargement of
the liver, spleen,
anemia, ascites,
sometimes CNS
involvement
Chronic Stage
Sensitive for moderate and heavy infections
Not adequate for light infections (less than 10
eggs/gram of stool)
Merthiolate-Iodine Formalin Concentration
Technique (MIFC)
For enumeration of eggs
Most commonly used for evaluating epidemiology,
effect of control measures, drug trials
Kato Katz Technique
Blood Flukes: Diagnosis
▪ Schistosomiasis
Rectal biopsy
Stool Examination Techniques
Intradermal tests for immediate cutaneous
hypersensitivity using adult worm extracts
Cercarian Hullen Reaction (CHR)
Indirect hemagglutination using adult worm and egg
antigens
Circumoval precipitin test (COPT)
Enzyme-Linked Immunosorbent Assay using soluble
antigens of adults and eggs
Schistosomiasis
Immunodiagnosis
