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River Blindness

River Blindness. A patient infected suffering from river blindness. This elderly man shows nodules, skin changes and blindness, all manifestations of the disease. Cause: parasitic roundworm transferred by fly bites. Micro worms swarm through skin and eyes. Economic implications:

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River Blindness

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  1. River Blindness • A patient infected suffering from river blindness. • This elderly man shows nodules, skin changes and blindness, all manifestations of the disease.

  2. Cause: parasitic roundworm transferred by fly bites. • Micro worms swarm through skin and eyes.

  3. Economic implications: • Increased disease frequency has resulted in limited farm laborers who can grow and harvest crops.

  4. Unsegmented Roundworms

  5. Unsegmented Worms Phylum Nematoda (round worms) -simplest animal to have a digestive system with TWO openings (mouth and anus advanced animal) -found in soil, lakes, oceans, polar and tropical environments, hot springs (everywhere)

  6. Ascaris the ones we will be dissecting

  7. Feeding: -most are free living carnivores/omnivores that eat algae, fungi, animals, decaying matter -have a pharynx (suck in food) -some are parasitic (affect plants and animals)

  8. Respiration -Diffusion of gases through body walls • Excretion: -metabolic wastes through body walls via diffusion and undigested wastes through anus NH3 O2 CO2

  9. Response: -simple nervous system -ganglia (group of nerve cells -not quite a brain) -sense organs and nerves that run down the body (movement/chemical detection) • Reproduction: -sexual reproduction (separate sexes) -complex life cycle (2 to 3 different hosts/organs)

  10. Four types of Nematoda • Ascaris-parasitic roundworm that lives in humans (and relatives in horses, dogs) Life Cycle Intestine (human) → produces eggs → leaves in feces → enters mouth via food/contaminated water → hatch in new host(human) → small intestine → blood vessel → lungs → throat (cough)→ swallowed → back in intestine...cycle starts from beginning

  11. 2. Hook worm -serious human intestinal parasite common in Southern US/tropical countries (1/4 people are infected) Life Cycle Eggs hatch outside of body and develop in soil → unprotected foot → sharp teeth/hook to burrow in the skin → enter blood stream → lungs → throat → back to intestine

  12. 3. Trichinosis/Trichonella -live and mate in the intestine -burrow eggs in intestine wall (1500 larvae) Life Cycle In a pig/rat: Larvae travel in blood vessels→ go to organs → tissues where it forms a cyst (inactive) -This inactive cysts is then eaten by humans (raw meat contains cyst, which becomes an active worm)

  13. Dinner is Ready?

  14. Filarial Wormsl -Tropical Asia/Africa -live in blood/lymph vessels of birds and mammals Life Cycle Host (carrying worms)→ mosquito (now carrying worms)→ releases worms and blocks passage of lymph vessels → swelling in vessels/tissues **cause elephantiasis **The following pictures may be disturbing… viewer discretion is advised 

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