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In this article we will discuss about:- 1. Fasciola Entire 2. T.S. Fasciola through Uterus 3. T. S. Fasciola through Testes 4. T.S. Fasciola through Cirrus Sac 5. T.S. Fasciola Posterior Sucker 6. Miracidium Larva of Fasciola 7. Redia Larva of Fasciola 8. Cercaria Larva of Fasciola.
Fasciola Entire:
1. It is commonly known as” Liver fluke” and is an endoparasite in the bile duct of sheep.
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2. It is cosmopolitan and pathogenic and measures about 20 to 50 mm. in length and 5 to 15 mm. In width.
3. Body leaf-like and flattened.
4. Mouth and oral sucker are situated on a small protuberance-the “head”.
5. A little behind the oral sucker is present a ventral sucker or acetabulum on the mid ventral side.
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6. In between the oral and ventral suckers, along the ventral surface, is present a small genital opening.
7. In the posterior part lies a sub-terminal excretory pore or “anus”.
8. Among the digestive organs the most conspicuous is intestine, which is a highly branched and convoluted structure.
9. They are hermaphrodite and the reproductive organs occupy almost whole of the body space.
10. The life cycle includes an intermediate host in the form of snail-Limnea (a mollusc).
11. It causes liver rot, liver cirrhosis, eosinophilia and anemia.
T.S. Fasciola through Uterus:
1. It is the slide of T. S. of fasciola passing through uterus region.
2. The section is some what elliptical and shows following features:
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(a) The outermost layer is a thick cuticle and is comprised of closely packed columnar cells.
(b) Embedded in the cuticle are present many small and thick spinules, which project above the cuticle and serve as organs of defense.
(c) Below the cuticle is present a circular muscle layer, a longitudinal muscle layer, oblique muscle layer and ultimately a parenchyma or mesenchyme.
(d) Sub-cuticular cells and vertical muscle strands are distributed in parenchyma.
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3. The body cavity is absent and the whole body space is filled with parenchyma cells thus imparting these animals an acoelomate grade.
4. Embedded in parenchyma are present larger rectangular or irregular egg – filled pouches the uteri.
5. Above and below the uterine pouches are present many small and rounded pouches – the testes filled with dots-like structures the sperms.
6. Near either narrow end, embedded in parenchyma, are present a few small, rounded, hollow and villinous structures-the intestine.
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7. In addition, distributed in parenchyma, are present large numbers of vitelline glands.
T. S. Fasciola through Testes:
1. It is the slide of T.S. of Fasciola passing through the region of testes.
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2. The section is some what elliptical and shows following features:
(a) The Outermost layer is a thick cuticle and is comprised of closely packed columnar cells.
(b) Embedded in the cuticle are present many small and thick spinules, which project above the cuticle and serve as organs of defence.
(c) Below the cuticle are present a circular muscle layer, a longitudinal muscle layer and ultimately a layer of parenchyma or mesenchyme.
(d) Distributed in the parenchyma are present sub-cuticular cells and vertical muscle strands.
3. The body cavity is absent and the whole body space in filled with parenchyma cells thus imparting these animals an acoelomate grade.
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4. Embedded in parenchyma are present large numbers of small rounded or oval pouches-the testes filled with many dots- like structures-the sperms.
5. Above or below the testes is present a few uterine pouches filled with eggs.
6. Near either narrow end, embedded in parenchyma, are present numerous villinous structures-the intestine.
7. In addition, distributed in parenchyma, are present large numbers of vitelline glands.
T.S. Fasciola through Cirrus Sac:
1. It is the slide of T.S. Fasciola passing through cirrus sac.
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2. The section is some what elliptical and shows following features:
(a) The outermost layer is a thick cuticle and is comprised of closely packed columnar cells.
(b) Embedded in the cuticle are present many small and thick spinules, which project above the cuticie and serve as organs of defence.
(c) Below the cuticle are present a circular muscle layer, a longitudinal muscle layer and ultimately a layer of parenchyma or mesenchyme.
(d) Distributed in the parenchyma are present sub-cuticular cells and vertical muscle strands.
3. The body cavity is absent and the whole body space is filled with parenchyma cells thus imparting these animals an acoelomate grade.
4. In the centre, embedded in parenchyma is present a large round pouch-the cirrus sac.
5. It contains an irregular hollow structure the cirrus, a large rounded, hollow and accentric seminal vesicle and many small rounded and hollow structures-the prostate glands.
6. Near either narrow end, embedded in parenchyma, are present a few small rounded, hollow and villinous structures the intestine.
7. In addition, large numbers of vitelline glands are present distributed in parenchyma.
T.S. Fasciola Posterior Sucker:
1. It is the slide of T.S. Fasciola passing through posterior sucker.
2. The section is some what elliptical and shows the following features:
(a) The outermost layer is a thick cuticle and is comprised of closely packed columnar cells.
(b) Embedded in the cuticle are present many small and thick spinules, which project above the cuticle and serve as organs of defense.
(c) Below the cuticle is present a circular muscle layer, a longitudinal muscle layer and ultimately a parenchyma or mesenchyme layer.
(d) Disturbed in parenchyma are present subcuticular cells and vertical muscle strands.
3. The body cavity is absent and the whole body space is lifted with parenchyma cells thus imparting these animals an acoelomate grade.
4. Along the lower surface in the centre is present a semicircular depression – the posterior sucker which is lined with a thick muscle layer.
5. Embedded in the parenchyma are present a pair of small, hollow tubular vas deferense near the central region and many hollow, circular and villinous intestinal caeca near either narrow end.
6. In addition large numbers of vitelline glands are present distributed in parenchyma.
Miracidium Larva of Fasciola:
1. It is the slide of Miracidium larva of Fasciola.
2. It is the first free swimming larval stage and is hatched out directly off the egg.
3. It is some what conical and flat and bears uniform ciliation all over.
4. At the anterior end the body is projected into a small and pointed apical papilla.
5. Body is covered with epidermal plates arranged in 5 rows. These plates are 6, 6, 3, 4 & 2 respectively in different rows.
6. In the region of apical papilla is present a large pitcher-shaped multinucleated apical gland in the centre and 1 to 3 pairs of penetration glands around it.
7. A tetra radiate brain and a pair of small and blackish eye spots are present above the penetration and apical glands.
8. The body wall is comprised of an outermost ciliated, a glandular epidermis, a well represented muscular layer and a layer of mesenchyme cells filling the whole body space.
9. In the posterior half is present a pair of flame cells [protonephridia] connected with long excretory ducts opening to out side through excretory pores.
10. The inside of the larva is filled with rounded germ balls of different sizes. These give rise to further larval stages.
11. After spending a short free swimming life it penetrates into a gastropod of genus Limnia or Planorbis (intermediate host) in which it transforms into a sporocyst stage. In case it does not find an intermediate host it dies.
12. The presence of apical gland, penetration glands and ciliated ectoderm are all larval parasitic adaptations.
Redia Larva of Fasciola:
1. It is the slide of Redia larva of Fasciola.
2. It is the third larval stage in the life cycle of Fasciola.
3. It develops from the germ balls present inside the sporocyst.
4. It is elongated and sac-like and it has a pair of downwardly directed projections in the posterior half-the lappet and a muscular ring in the anterior half-the collar. They act as organs of locomotion.
5. The bodywall of redia is comprised of a thick cuticle, a squamous epithelium, a muscular and a mesenchyma layer.
6. An oral sucker surrounding the mouth, a small pouch – the intestine terminating into a blind-sac are present near the anterior tip.
7. The inside of redia is filled with numerous germ balls, a few daughter rediae and a few cercaria, which escape out through birth pore situated on one side behind the collar.
8. Near the lappets are present branched flame cells which are attached to the wall through a common excretory duct.
9. It gives rise to daughter rediae and the next larval stage-the cercaria.
Cercaria Larva of Fasciola:
1. It is the slide of Cercaria larva which is the IVth larval stage in the life-cycle Fasciola.
2. It develops from germ balls inside t redia larvae which are present inside the digestive gland of intermediate host – the mollusc (Limnaea).
3. It is characterized by having a flat and c. body and a long tail.
4. It is a free swimming larval stage.
5. From inside the redia it escapes through birth pore and then to outside water through the alimentary canal of the intermediate host.
6. In this larva the digestive organs are- mouth surrounded by a muscular oral sucker, a highly muscular pharynx, a small oesophagus, and a bifid intestine.
7. In the space between two limbs of intestine is present a ventral sucker and a mass of germ cells -the reproductive rudiment.
8. Near the joint of tail with body is present a globular excretory bladder opening to outside through a pair of excretory pores. The bladder is connected with a pair of diverticula in-front and an excretory duct behind.
9. The flame cells (protonephridia) increase in number through simple multiplication and are situated on either side of intestinal limbs.
10. Body wall, as usual, is comprised of a cuticle, an epithelial layer, a muscular layer and parenchyma (mesenchyme) cells.
11. The most important feature of the larva is the presence of numerous cytogenous glands, which are distributed among the flame cells and help In secreting a cyst in order to transform the larva Into next stage.
12. It leads a short free swimming life, after which it is attached to water plants and transforms into last stage – the metacercaria.
