(F) Trematodes: Introduction and Diecious Trematodes (module and lecture-based) Flashcards
- mostly are hermaphrodites
- may require one or more intermediate hosts
- can be divided in two, the monoecious flukes and the diecious flukes
Trematodes
Trematodes
Phylum
Platyhelminthes
Trematodes
- Cylindrical bodies
- Flattened or leaf-shaped bodies
- Only one inter-mediate host
- Produces non-operculate, embryonated eggs with miracidium
- Produces operculate eggs
A. Monoecious flukes
B. Diecious flukes
Pasagot po each no. thx
BABBA
Trematodes
Monoecious flukes need two intermediate hosts the first of which is almost always a species of?
snail
Trematodes
- Paragonimus westermani
- Schistosoma japonicum, S. mansoni and S. haematobium
- Fasciola hepatica, Clonorchis sinensis, Opistorchis felineus, O. viverrini
- Fasciolopsis buski, Echinostoma ilocanum, Heterophyes heterophyes, Haplorchis yokogawai, Metagonimus yokogawai
A. Blood Flukes
B. Intestinal Flukes
C. Lung fluke
D. Liver flukes
C, A, D, B
Trematodes
Flukes are generally provided with structures that are, except:
A. Nervous
B. Excretory
C. Circulatory
D. Digestive
E. Reproductive
C
Trematodes
- consists of a paired ganglion cells situated at the anterior part, at the back of the esophagus or pharynx, and nerve trunks that send fibers to the back, lateral, and ventral sides of the organism’s body
- consists of an oral cavity inside the oral sucker, which is continuous with the pre-pharyngeal tube, a muscular pharynx, esophagus, and two intestinal ceca with blind ends
- bilaterally symmetrical, which opens at the dorsal and posterior portion of the worm; flame cell
- described an inverted Y figure
A. Digestive
B. Excetory
C. Nervous
may na-repeat na answer
CABA
Trematodes
- Also known as solenocyte is the basic unit of the excretory apparatus
- joined by capillaries, which in turn are united forming the excretory tubules
Flame cell
Trematodes
Mode of excretion
regurgitation
wala nga sila anus kaya sa oral cavity uli ang daan
Trematodes
Foods of trematodes
- liquid and semi-liquid nutrients
gets from the environment
Trematodes
What happens to unused foods, as well as wastes?
regurgitated
Trematodes
If ever the worm needs oxygen, it is taken in via the?
skin
Trematodes
- hermaphrodite
- Female: has one ovary, an oviduct, ootype, multiple vitelline glands, seminal receptacle, Mehli’s glands, uterus, and genital pore
- Male: includes the testes, oftentimes paired in most species but multiple among blood flukes, vas efferens, vas deferens, seminal vesicle, ejaculatory duct, prostate glands, genital atrium, and a genital pore
- may produce either embryonated or immature eggs depending upon the species
Monoecious fluke
Trematodes
Stages of Development (pattern)
Egg – larva - adult
Trematodes: monoecious flukes
Infective stage to the snail host
dalawa
miracidium or egg to other molluscan or snail host
Trematodes:
The miracidium, once inside the snail (intermediate host) develops into a?
sporocyst
Trematodes:
- sac-like structure, with embryonic cells at the posterior part
- has a mouth with muscular pharynx, a blind and a non-forked cecum, a birth pore, and, in some species, locomotion organelles; released thru the birth pore
- the end-stage development in the snail host; a free-swimming, non-feeding larval stage, with penetration glands, attracted to light (phototaxis), and with a short life span
A. Cercaria
B. Redia
C. Sporocyst
CBA
ang development ay from miricidium -> sporocyst -> redia -> cercaria
Trematodes:
4 types of cercaria
(A) lophocercus or simple tail
(B) leptocercus or keel tailed
(C) microcercus
(D) furcocercus or fork-tailed
Trematodes:
- keel tailed, has a tubular tail with a thin membrane of the skin that serves as the rudder
- has no tail but instead provided with a small spherical appendage posteriorly
- has a tail that is bifurcated; found among diecious flukes
- simple tubular tail
(A) lophocercus
(B) leptocercus
(C) microcercus
(D) furcocercus or fork-tailed
BCDA
Trematodes:
How does the cercaria of monoecious flukes leaves the snail host?
death of the snail or overpopulation
Trematodes:
- swims in the water and finds the second intermediate host where it becomes encysted due to a fibrous capsule secreted by the intermediate host
- tail is cast off when it enters the body of the intermediate host
cercaria
Trematodes:
The encysted form, present among monoecious flukes, is called?
metacercaria
Trematodes: Diecious
infective stage to the definitive host
cercaria
Trematodes: Mono
infective form to the definitive host
metacercaria
Trematodes: Mono
MOT
ingestion of the metacercaria contained in the flesh of the second intermediate host
Trematodes: Mono
Ingested metacercaria undergoes excystation in the?
upper level of the small intestine
Trematodes: Diecious
MOT (mainly)
skin penetration
Cercaria may also be taken in orally through drinking water that is contaminated with the organism. However, the cercaria will still enter the surface area of the oral cavity to enter the circulation or lymphatics to reach their predilection site for maturity.
Trematodes: Diecious
- causing vesical schistosomiasis or urinary bilharziasis or schistosomal hematuria
- present in Africa (Sudan and Ethiopia), Central and West Africa, North Africa, West Asia (Lebanon, northern Syria, Arabia, Iraq, and Iran), and east coast of Africa (Malagasy, Mauritius, and Reunion)
- also found in India (Mumbai), Somalia, Tanzania, Zambia, and Angola.
Schistosoma haematobium
Schistosoma haematobium
AKA
vesical blood fluke
Schistosoma haematobium
Inhabits (primarily)
veins
Schistosoma haematobium
may be recovered where (commonly)
urine than stool
- causing schistosomiasis mansoni or Manson’s intestinal schistosomiasis or bilharziasis
- found in some specific areas of Africa, South America, islands at the Caribbean Sea, Congo Basin, north-eastern Brazil, Guinea island, Kenya, Malawi, some parts of Venezuela, West Indies, and Puerto Rico
Schistosoma mansoni
Schistosoma mansoni
AKA
Manson’s blood fluke
Schistosoma mansoni
Inhabit
lumen of the inferior mesenteric veins
between inferior mesenteries and veins draining the urinary bladder
Schistosoma mansoni
Eggs are recovered (mainly)
stool than in the urine
- causing schistosomiasis japonica is confined to some areas in the Far East including Japan, China, the Philippines (Leyte, Samar, Mindanao, Mindoro, and Sorsogon), and Thailand.
Schistosoma japonicum
Schistosoma japonicum
Inhabit
superior mesenteric vessels
vessels draining the small intestine and early part of the large intestine
Schistosoma japonicum
The eggs are recovered in
stool specimen
- Female: Single ovary situated at the mid-point of its body.
- Female: Single ovary situated anterior to the mid-point of its body.
- Female: Single ovary situated posterior to the mid-point of its body.
A. S. japonicum
B. S. mansoni
C. S. haematobium
ABC
- Male: Integument with coarse trabeculations; Intestinal ceca bifurcate at the level of the ventral sucker and are reunited anterior to the mid-point (early union).
- Male: Integument is smooth, no trabeculations; Intestinal ceca bifurcate at the level of the ventral sucker and are reunited very much posterior to the mid-point (very late union).
- Male: Integument with fine trabeculations; Intestinal ceca bifurcate at the level of the ventral sucker and are re-united late, which is about the mid-point of ahead of it of its body.
A. S. haematobium
B. S. japonicum
C. S. mansoni
CBA
- Testes: 4 – 5 small, ovoid-shaped, in cluster.
- Testes: 6 - 8 large, oval-shaped, in a single row.
A. S. haematobium
B. S. mansoni
C. S. japonicum
- A
- B & C
- Egg: Small, or abbreviated, spine (diagnostic); Embryonated when laid
- Egg: Prominent terminal spine (diagnostic)
- Egg: Long and prominent lateral spine
A. S. haematobium
B. S. mansoni
C. S. japonicum
CAB
Blood flukes: Life cycle
Location of Embryonated eggs
Accumulate inside the blood vessels
Intermediate host
1. Biomphalaria species (B. glabrata)
2. Oncomelania species (O. quadrasii)
3. Bulinus sp., Ferrisia tenuis, Planobarius metidjensis
A. S. haematobium
B. S. mansoni
C. S. japonicum
BCA
Blood flukes: Life cycle
The mucus that comes when eggs are laid causes irritation of the intestinal walls or the urinary bladder resulting to?
hyperperistalsis
Blood flukes: Life cycle
Hatching
Water
Blood flukes: Life cycle
Released embryo swims freely and attaches to the?
mucus trail left by the snail host
Blood flukes: Life cycle
The miracidium enters the body of the snail host and developed into a ___________? and that later produces ____________? which develops into ____________?
mother sporocyst (S1)
daughter sporocyst (S2)
fork-tail cercaria
Blood flukes: Life cycle
What leaves the snail is a non-feeding, free- swimming, short-lived organism that exhibits phototaxis
cercaria
Blood flukes: Life cycle
infective stage to man
fork-tail cercaria
Blood flukes: Life cycle
MOT to definitive host
Skin penet
Blood flukes: Life cycle
Once it enters the skin to enter the capillaries, it passes thru 3 organs to reach schistosomula stage
inferior vena cava, the right side of the heart, and later the lungs
Blood flukes: Life cycle
What stage breaks into the veins of the lungs and goes against the flow of blood until it reaches its habitat where it matures and copulates.
schistosomula stage
Blood flukes: Life cycle
TOF. The female produces eggs, which are unembryonated.
F (embryomated)
Blood flukes: Pathogenesis, Pathology and Clinical Manifestations
organs most severely affected
liver and the intestinal tract
Blood flukes: Pathogenesis, Pathology and Clinical Manifestations
antigenic to man
stages (2)
eggs and cercariae
Blood flukes: Pathogenesis, Pathology and Clinical Manifestations
- Does not produce significant effects
- Granuloma (pseudo-tubercle) formation, acute hepatitis (parasitic hepatitis),
- Schistosomal Dermatitis, urticarial rashes, edema of subcutaneous tissues, fever, pruritus, lesions at the lower extremities
- Massive scar tissue formation (granuloma), parasitic cirrhosis, hemorrhoids, cirrhotic liver,
A. Stage I
B. II
C. III
D. IV
BCAD
Blood flukes: Pathogenesis, Pathology and Clinical Manifestations
- The immune system may be stimulated and antibodies against the cercariae are produced. This is the basis for the serologic test Cercaria Huellen Reaction (CHR), which may give a positive result at this stage of schistosomiasis
A. Stage I
B. II
C. III
D. IV
A
Blood flukes: Pathogenesis, Pathology and Clinical Manifestations
At the end of this stage, the females may already be producing some eggs and they are already at the final site for habitation.
A. Stage I
B. II
C. III
D. IV
B
Blood flukes: Pathogenesis, Pathology and Clinical Manifestations
- The miracidium inside the egg secretes mucus that irritates the intestines causing eggs to escape from the vessels into the perivascular tissues or into the lumen of the intestines. Eggs, in the tissues, are sequestered by eosinophils. Eggs maybe carried to different sites by the circulation.
- The ability of the eggs to stimulate antibody production leads to the development of a serologic test called Circum-Oval Precipitin Test (COPT). This stage of the infection is also marked with plenty of eggs being extruded in the feces (or urine depending upon the species of the worm).
A. Stage I
B. II
C. III
D. IV
C
Blood flukes: Pathogenesis, Pathology and Clinical Manifestations
Most common site for eggs accumulation
Liver (stage 3)
Blood flukes: Pathogenesis, Pathology and Clinical Manifestations
- Granuloma in the liver can cause obstructive pressure on blood vessels passing through this organ, such as the portal veins
- Blood flow is impeded causing dilatation of the smaller branches of the vessels.
- There will be enlargement and engorgement of the superficial vessels of the abdomen and development of esophageal varices, which may rupture, and patient may vomit blood. Dilated superficial vessels on the abdomen results to spider nevi or caput medusa (dilated vessels at the navel)
A. Stage I
B. II
C. III
D. IV
D
Blood flukes:
Eggs of S. japonicum and S. mansoni may be recovered in the
Feces
Blood flukes: Laboratory Diagnosis of Schistosomiasis
May be done during the early stage of schistosomiasis. To know if eggs are viable, the schistosome egg-hatching procedure may be done
CHR (Ceceria Hueller Reaction)
pa-correct nalng
Blood flukes: Laboratory Diagnosis of Schistosomiasis
likely to show positive result during stages III and IV of schistosomiasis, which tests for the antibodies against the eggs of a particular species of blood fluke
COPT
Blood flukes: Laboratory Diagnosis of Schistosomiasis
likely to show positive result during stages III and IV of schistosomiasis, which tests for the antibodies against the eggs of a particular species of blood fluke
COPT
Blood flukes: Laboratory Diagnosis of Schistosomiasis
prepared from mice previously and artificially infected in the laboratory
Lyophilized eggs
Blood flukes: Laboratory Diagnosis of Schistosomiasis
Patients’ serum is incubated with the eggs. A positive result is seen as?
bleb formation around the eggs, signifying precipitation reaction
Blood flukes: Laboratory Diagnosis of Schistosomiasis
This laboratory diagnosis of the liver is also of help in the diagnosis although, not quite specific.
Ultrasonography, as well as other imaging methods such as CT scan or MRI
Blood flukes: Laboratory Diagnosis of Schistosomiasis
may also be done to demonstrate the eggs in the tissues.
Biopsy of the rectal
Blood flukes: Laboratory Diagnosis of Schistosomiasis
may be considered to demonstrate the eggs, but it is a dangerous procedure because of potential hemorrhage (internal) that is a complication of the procedure.
Liver biopsy
Blood Flukes:
Treatment and Prevention
- Treatment: praziquantel, taken for 1-2 days, or Steroid medication
- Measure: sanitary disposal of human waste, control of snails, control of rats, provision of clean, safe, and potable drinking water, and early diagnosis and treatment of cases.
