Blood Fluks Flashcards
What are the two main species of blood flukes discussed in the document?
Schistosoma haematobium and Schistosoma mansoni.
What is the intermediate host for Schistosoma haematobium?
Snails from the genus Bulinus.
What is the intermediate host for Schistosoma mansoni?
Snail (Biomphalaria).
What is the infective stage for both Schistosoma haematobium and Schistosoma mansoni?
Cercaria.
What is the diagnostic stage for both Schistosoma haematobium and Schistosoma mansoni?
Egg.
How is schistosomiasis transmitted to humans?
Through direct contact with contaminated freshwater where infective cercariae penetrate human skin.
What is the definitive host of Schistosoma haematobium?
Human.
Where do adult Schistosoma haematobium worms reside in the human body?
Urinary bladder veins.
Describe the adult male Schistosoma haematobium.
Shorter and thicker than the female. The body is curved to form a gynecophoral canal, which holds the female worm. Oral and ventral suckers. (3–5) small globular testes situated in one line just behind the ventral sucker.
Describe the adult female Schistosoma haematobium.
Longer and thinner than the male. Oral and ventral suckers. An oval ovary is lying just in front of the junction of the two intestinal cacca. The genital pore opens posterior to the ventral sucker.
Describe the egg of Schistosoma haematobium.
Large elongated, rounded at both ends with terminal spine, contains fully developed embryo.
What is the gold standard diagnostic method for Schistosoma haematobium?
Urine Microscopy. A midday urine sample (preferably collected between 10 AM – 2 PM) is examined under a microscope. The sample is centrifuged, and the sediment is examined for Schistosoma haematobium eggs.
What is the habitat of adult Schistosoma mansoni worms in humans?
Mesenteric veins (small intestine).
Describe the adult male Schistosoma mansoni.
Shorter than female. Oral and ventral suckers. The male has 6–9 small testes forming grape-like clusters behind the ventral sucker.
Describe the adult female Schistosoma mansoni.
Similar to S. haematobium but the ovary is situated anteriorly and the uterus is shorter.
Describe the egg of Schistosoma mansoni.
Large elongated, rounded at both ends with lateral spine, contains fully developed embryo.
What is the gold standard diagnostic method for Schistosoma mansoni?
Microscopic Examination of Stool (Kato–Katz Technique).
Describe the miracidium stage of Schistosoma spp..
Oval, pyriform, ciliated. Cone-shaped anterior end with a small papilla. Primitive digestive tract anterior and lateral paired secretory glands. Germinal cells posterior. No eye spot.
Describe the cercaria stage of Schistosoma spp..
Elongated pear-shaped with rounded ends. Forked tail. Anterior and ventral suckers. Cluster of cells posterior part of the body.
Describe the shell shape of Bulinus truncatus (intermediate host for S. haematobium).
Bulinus truncatus has a left-coiling shell, meaning it spirals to the left when viewed from the apex. Color: Shell is light brown to yellowish. Aperture (Opening): Large and oval-shaped, with a thin outer lip. Whorls: Usually 4–5 whorls.
Describe the shell shape of Biomphalaria alexandrina (intermediate host for S. mansoni).
Small to medium in size, smooth and bilaterally flattened (button-like). The opening is rounded with sharp edges.
