SS3 Second Term Agricultural Science Lesson Note – Meaning of Livestock Parasite

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 WEEK 5-7

MEANING OF LIVESTOCK PARASITE

A parasite is an organism living in or on another organism call the host. The host is usually bigger and stronger than the parasite.  The parasite derives benefits (food) from the host while the host is harmed or injured during the association.  Parasite which lives inside its host is call endoparasite, e.g., tapeworm, ascaris or roundworm and liverfluke.  Parasite which lives on or outside the host is called ectoparasite, e.g., ticks, lice and mites.

ENDOPARASITES

1. Tapeworm (Taenia solium): Tapeworm is along endoparasite flatworm with a very small head, neck and long segmented body.  It belongs to the group called platyhelminthes.  Taenia solium is found is pigs while taenia saginata is found in cattle.  The head, also known as scolex has suckers and hooks with which it holds firmly to the intestinal wall of its primary host (man).  Pig is the secondary host. The body segments known as proglottides are arranged is long row formed from the neck.  At the neck region, the proglottides are small and young while those far from the neck are the largest and the oldest.

Life Cycle of Tapeworm

Tapeworm is a hermaphrodite, that is, it has both male and female reproductive organs and as such, it can fertilize itself.  When a matured and fertilized proglottide pulls off the body of the adult tapeworm, it drops or passes out with the faeces of man to the ground from where pig can pick it up during feeding. It eventually gets to the intestine of the pig where an enzyme acts on the egg and liberates the embryo which can find its way into the blood stream by passing through the intestinal wall and it finally deposited in the muscle or heart of the pig.  Each embryo forms a cyst round itself to become bladder worm with the head turned inside out, so that its sucker lies on the inside.  When raw or under-cooked pork or beef containing the bladderworm is eaten, the digestive enzymes of man dissolve the bladderworm and the young tapeworm with its head turned inside out emerges.

 ECONOMIC IMPORTANCE OF TAPEWORM ON MAN

1. Abdominal pain or discomfort
2. Anaemia
3. Weakness
4. Indigestion and vomiting

The combined effects of these symptoms are called taeniasis.

CONTROL OF TAPEWORM

1. All meat should be examined for bladderworm before selling to the public
2. Meat should be properly cooked before eating

• Practice good sanitary measures so that it will not be possible for animals to come in contact with or eat human faeces

Life Cycle of Liverfluke

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