Taenia solium and Fasciola hepatica are parasitic flatworms belonging to two different groups. T. solium is a cestode (pork tapeworm) having a long and segmented body. The adult worm is present in the small intestine of humans, while pig acts as its major intermediate host.
Infection with T. solium can occur in different forms. Undercooked pork containing cysticerci can produce taeniasis. On the other hand, ingestion of its eggs may result in cysticercosis.
Fasciola hepatica is a trematode (liver fluke) with broad and leaf-shaped body. The adult flukes are mainly found in the bile ducts.
Its life cycle involves a freshwater snail as the intermediate host. Infection takes place by ingestion of metacercariae present on contaminated aquatic vegetation. This infection is referred to as fascioliasis.
Taenia solium
Taenia solium is a cestode, commonly referred to as the “pork tapeworm”. The adult worm has a long, ribbon-like and segmented body.
Humans act as the definitive host, and the adult worm is found in the small intestine. Pig acts as the major intermediate host.
The scolex contains four suckers and a rostellum provided with hooks. These structures help the worm in attachment with the intestinal wall.
Infection with T. solium occurs in two forms. Eating undercooked pork containing cysticerci produces taeniasis. On the other hand, ingestion of eggs can produce cysticercosis, where humans act as an intermediate host.
When the cysticerci are present in the central nervous system, this condition is referred to as neurocysticercosis.
Fasciola hepatica
Fasciola hepatica is a trematode, also known as the “liver fluke”. It has a broad and leaf-shaped body.
The adult flukes are mainly found in the bile ducts of the definitive host. Sheep, cattle and other mammals are common hosts. Humans can also become infected.
A freshwater snail acts as the intermediate host. Within the snail, different larval stages are developed and cercariae are released into the water. These later form metacercariae on aquatic vegetation or remain in water.
Human infection takes place after ingestion of these metacercariae. The immature flukes migrate through the intestinal wall and liver. Later, they reach the bile ducts and develop into adult flukes.
This infection is referred to as fascioliasis.
Taenia solium vs Fasciola hepatica
| Features | Taenia solium | Fasciola hepatica |
|---|---|---|
| Group | It is a cestode (tapeworm). | It is a trematode (fluke). |
| Common name | Commonly referred to as pork tapeworm. | Commonly known as liver fluke. |
| Body shape | Body is long, flattened and divided into many segments called proglottids. | Body is broad, flat and leaf-shaped. It is unsegmented. |
| Attachment organ | Scolex has four suckers and an armed rostellum containing hooks. | Oral and ventral suckers are present. |
| Adult location | The adult worm is present in the small intestine of humans. | Adult flukes are mainly found in the bile ducts. |
| Definitive host | Human is the definitive host. | Sheep and cattle are common definitive hosts. Humans can also become infected. |
| Intermediate host | Pig acts as the major intermediate host. Humans may also act as intermediate host after ingestion of eggs. | A freshwater snail acts as the intermediate host. |
| Infective stage for humans | Cysticercus causes intestinal infection. Eggs can produce cysticercosis. | Metacercaria is the infective stage for humans. |
| Mode of infection | Eating undercooked pork containing cysticerci results in taeniasis. Ingestion of eggs can result in cysticercosis. | Infection takes place by ingestion of metacercariae, commonly through contaminated aquatic plants. |
| Main disease | Causes taeniasis and cysticercosis. Cysticerci in the central nervous system produce neurocysticercosis. | Causes fascioliasis. |
| Larval migration | Cysticerci develop in tissues of the intermediate host after ingestion of eggs. | Immature flukes pass through the intestinal wall and migrate through the liver before reaching the bile ducts. |
Similarities between Taenia solium and Fasciola hepatica
Some of the similarities between Taenia solium and Fasciola hepatica are-
- Both are parasitic flatworms belonging to the phylum Platyhelminthes. They infect humans as well as animals.
- Both have a complex life cycle involving more than one host. An intermediate host is required for the development of larval stages.
- Adult worms of both parasites are hermaphroditic. Male and female reproductive organs are present in the same individual.
- Suckers are present in both and are used for attachment within the host. T. solium has four suckers on its scolex, while F. hepatica contains oral and ventral suckers.
- Eggs of both parasites leave the definitive host through feces. These eggs take part in continuation of their life cycle.
- Human infection with both parasites can occur through ingestion of the infective stage. In T. solium, cysticerci present in infected pork produce intestinal taeniasis. In F. hepatica, metacercariae are ingested mainly with contaminated aquatic vegetation or water.
- Both are zoonotic parasites and have importance in human as well as veterinary health. Their animal hosts help in maintaining the life cycle and transmission of infection.
References
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