Parasites

1. Parasites

2. Symbiotic Relationships • Symbiosis- animals of different species that live in close association with each other • At least 3 kinds of symbiosis

3. Mutualism • Beneficial to both species

4. Oxpecker and Impala

5. Commensalism • One benefits, the other is not harmed

6. Cattle Egret

7. Parasitism • Beneficial to one specie, harmful to the other • Accounts for almost all symbiosis • The animal that lives off of the other animal is the parasite • The animal that the parasite lives on is the host

8. Ticks

9. Why are parasites a big deal? • Parasitism causes almost a billion dollars worth of damage a year. • There are different types of damage caused.

10. Anemia • Most parasites live off the blood of the host animal. • Continual loss of blood leads to anemia. • Blood provides animals with oxygen and food nutrients. • Parasites cause blood supply to diminish, thus causing the animal to get ill from lack of oxygen and nutrients. • Animals become sluggish, feel poorly, and don’t grow like they should.

11. Weakened Immunity • Animals that are hosts to parasites are in a weakened condition. • This makes them more likely to get diseases. • Their immune system weakens, making it harder to fight off common diseases.

12. Parasites as Carrying Agents • Parasites can carry disease organisms from one animal to another. • An insect may feed on an infected animal and then feed on a healthy animal and transmit disease organisms.

13. Malaria

14. Other Effects of Parasites • Animals with parasites are almost always uncomfortable. • Parasites cause irritation of the skin, intestinal tract, or other parts of the body. • Animals with parasites spend most of their time trying to alleviate the pain and itch, and therefore, they perform poorly.

15. Categories of Parasites • Internal- inside the body • External- on the hair or skin

16. Life Cycle of Parasites • Some parasites live their entire life on or in the host animal, but most live only a portion of their life on or in the host. • Insects go through four complete life stages from the time they hatch until they are mature adults capable of reproducing. • This cycle is called metamorphosis. • At each of the stages, the parasite looks completely different.

17. Insect Development

18. Internal Parasites • May feed on the animal’s blood or on feed that passed through the animals • Divided into three major groups: roundworms, tapeworms, and flukes

19. Roundworms

20. Roundworms • Cause more damage to livestock than another group of internal parasites • Infect almost all species and live in digestive tracts • Burrow into the lining of the host’s stomach and suck the animals blood

21. Roundworms • By digging into the stomach lining, the worm damages the tissue of the stomach, enzymes are not produced, and the host cannot digest food very well. • Poisons are released by the worms as they digest their food and excrete the waste into the host animal. • These cause the host to get ill.

22. Roundworms • Worms lay eggs in the stomach of the host and pass out of the animal in the feces. • While in the feces, the eggs hatch into larvae and the larvae crawl out onto a blade of grass. • A grazing animal then eats the grass and ingests the larvae. • Once ingested, the worms burrow into the stomach lining, lay eggs, and repeat the process.

23. Roundworms • Another type of roundworm is the strongyle. • Similar to stomach worms, except they live in the intestine. • They cause scar tissue in the small intestine and by sucking blood from the host animal. • A damaged intestine reduces the efficiency of the digestive system. • These are particularly damaging to horses and can cause colic.

24. Roundworms

25. Roundworms

26. Tapeworms • Worms are segmented. • Each of these segments contains both male and female reproductive organs, meaning each segment can produce fertilized eggs. • Segments break off the body of the worms and reproduce.

27. Tapeworms • Tapeworms cause less damage than roundworms because they don’t feed on blood or cause scarring of the digestive tract. • They live in the small intestine. • Some reach the length of 25 feet. • They feed off of the animal’s feed that passes into the intestine.

28. Tapeworms • Life cycle begins when the segments of the tapeworm break off and pass through in the feces. • Each segment contains eggs that hatch out in the feces. • The eggs are eaten by a small mite called an oribatid mite that lives in the grasses found in pastures.

29. The Role of the Mite • Mite serves as an intermediate host. • Intermediate host is not harmed by the parasite. • Since the mite lives on grasses, they are swallowed by grazing animals. • The eggs are then passed through the animal to the small intestine, where they hatch and live until maturity.

30. Tapeworm

31. Flukes • Small, seed-shaped flatworms that live in various parts of the host animal • Most damaging of the flukes live in the liver • Adults lay eggs in the bile duct, and they pass through to the intestines and out the feces. • These parasites need an intermediate host.

32. Flukes • In order for the eggs to hatch, they must land in water. • After the larvae hatch, they swim in search of snails to serve as intermediate hosts. • Once the they find the snails, they enter them to develop and reproduce. • The larvae divide asexually.

33. Flukes • The new larvae emerge and attach to plants in or near the water. • Livestock eat the plants and become infected with the flukes. • The flukes eat their way through the walls of the digestive tract and migrate to the liver where they feed on the host’s blood.

34. Flukes • Begin to lay eggs in 3 months • Flukes cause liver damage • Livers from animals infected with flukes are not fit for human consumption.

35. Flukes