Parasitology

1. Parasitology Metazoans and Exoparasites Part II

2. Meatazoans Three Classes Trematodes (flukes-flat worms) Cestodes (tape worms) Nematodes (round worms)

3. Metazoans Major Stages of Life Cycle Ova Adult (Mature Parasite)

4. Metazoans Monecious - having male and female reproductive organs in the same animal. Diecious - sexually distinct; denoting species in which male and female genitals do not occur in the same individual

5. Trematoda Most trematodes have complex life cycles, with larval stages parasitizing one or more species that are different from host of adults. Larval stages of some medically important species include miracidium, redia, cercaria, and metacercaria. Most trematodes are endoparasites. They include several parasites that have an enormous impact on human populations, such as human liver flukes and the blood flukes.

6. Trematoda Clonorchius sinesis causes hepatic portal disease, very painful, affects liver

8. Trematoda Schisotosoma mansoni blood flukes that targets organs that are fed by blood.

10. Trematoda Fasciola hepatica, also known as the common liver fluke or sheep liver fluke, is a Parasitic flatworm of the class Trematoda, phylum Platyhelminthes that infects liver of various mammals, including humans.

11. Cestoda Cestoda is a class of parasitic flatworms, commonly called Tapeworms. Tapeworms live in the digestive tract of vertebrates as adults and often in the bodies of various animals as juveniles.

12. Cestoda Taenia saginata The beef tapeworm can grow up to 40 feet long (12 m); other species may grow to over 100 feet (30 m).

13. Cestoda Taenia solium This infection is caused by ingestion of eggs shed in the feces of a human tapeworm carrier. Pigs and humans become infected by ingesting eggs or gravid proglottids. Humans are infected either by ingestion of food contaminated with feces containing eggs, or by autoinfection

15. Cestoda Echinococcus granulosus Hydatid worm parasitizes the small intestine of canids as an adult, but which has important intermediate hosts such as livestock and humans, where it causes hydatid disease. Hydatid disease is treated with surgery, taking special care to leave the cyst intact so new cysts do not Form.

17. Clues of Tapeworm Involvement

18. Nematoda (Round Worms) Nematoda , phylum consisting of about 12,000 known species, and many more predicted species of worms (commonly known as roundworms or threadworms). Nematodes live in the soil and other terrestrial habitats as well as in freshwater and marine environments. Many are damaging parasites of plants and animals, including humans.

19. Nematoda (Round Worms) Ascaris lumbricoides – fairly long, get together in balls and start breeding

20. Nematod (Round Worm) Necator americanus hook worm. Likes to penetrate in soft skin between toes then migrates from there to other site in the body.

21. Nematod (Round Worm) Trichinella spiralis Trichinellosis, also called trichinosis, is caused by eating raw or undercooked meat of animals infected with the larvae. Infection occurs commonly in certain wild carnivorous (meat-eating) animals but may also occur in domestic pigs.

22. Nematod (Round Worm) Enterobius vermicularis Pin worms Lays eggs on the anus. Causes a very itchy bum and prolapsed rectum.

24. Exoparasites These don’t really cause Infection. They are responsible for infestations. Insecta (6 legs) – fleas, Lice Arachnidia (8 legs) – ticks, mites

25. Exoparasites Body Louse Pediculus humanus Lice are six-legged blood-sucking parasitic insects that live near the surface of the skin, often clinging to the shafts of human hair. They can travel quickly, up to 10 inches per minute, which explains why they are so contagious. Infestation with lice is called “pediculosis.” In the U.S., head lice and pubic (crab) lice are the most common forms of pediculosis.

26. Pediculushumanus Direct and prolonged head-to-head contact is the usual mode of head lice transmission; as such, lice are typically spread between people who know each Other Sharing of inanimate objects that come in contact with the hair or scalp, such as hats, scarves, or hairbrushes, may also cause the spread of head lice, though this is less Common. Contrary to popular belief, lice cannot jump from one head to another, and they cannot survive for long off of the human Body.

27. Exoparasites Crab Louse Pthirus pubis Pubic lice (or crab lice) are usually transmitted sexually and are among the most contagious of STDs. Condoms do not prevent the spread of pubic lice. Nonsexual transmission of public lice is also possible.

28. ExoparasitesBody Louse comparison to Crab Louse Body louse claw are adapted for round hair common with body and head hair. Crab louse claw is adapted for oval shaped hair common with pubic hair and eye lashes.

29. Exoparasites (Bed Bugs) Bed bugs, Cimex lectularius , are blood feeding parasites of humans, chickens, bats and occasionally domesticated animals (Usinger 1966). Bed bugs are suspected carriers of leprosy, oriental sore, Q-fever, and brucellosis (Krueger 2000) but have never been implicated in the spread of disease to humans (Dolling 1991).

30. Exoparasites Ticks Ticks are blood-feeding parasites that are often found in tall grass and shrubs where they will wait to attach to a passing host. A tick will attach itself to its host by inserting its chelicerae (cutting mandibles) and hypostome (feeding tube) into the skin. The hypostome is covered with recurved teeth and serves as an anchor.

31. Exoparasites Ticks

32. Exoparasite Scabies Scabies is a contagious ectoparasite skin infestation characterized by superficial burrows and intense pruritus (itching). It is caused by the mite Sarcoptes scabiei. The word scabies itself is derived from the Latin word for "scratch" (scabere).

33. Exoparasites Scabies Scabies is highly contagious and can be spread by scratching, picking up the mites under the fingernails and simply touching another person's skin. They can also be spread onto other objects like keyboards, toilets, clothing, towels, bedding, furniture, and anything else that the mite may be rubbed off onto, especially if a person is heavily infested. The parasite can survive up to 14 days away from a host, but often do not survive longer than two or three days away from human skin.[

34. Exoparasites Insects and arachnids are much more important as vectors that as parasites. Mosquitoes transmit malaria Ticks transmit Lyme’s disease Fleas transmit plague