1. Worms What’s Eating You for Dinner ?

3. FLATWORMS PYLUM: Platyhelminthes
FREE LIVING PARASITIC
Planaria Flukes & Tapeworms
FLATWORMS ARE ACOELOMATES

4. PLANARIA
NOT PARASITES

5. GASTROVASCULAR CAVITY (Combination Digestive & circulatory)
One opening digestive cavity

8. FLAME CELLS Collect excess water and nitrogen waste
Excreted through pores in skin
Moving cilia look like little “flames”

9. REPRODUCTION SEXUAL- (hermaphrodites but trade with partner) ASEXUAL-
can use regeneration to
grow a new organism from parts

10. PARASITIC WORMS
Animal host where ADULT feeds and reproduces = PRIMARY HOST
Animal host where LARVAL form lives and feeds = INTERMEDIATE
HOST

11. HUMAN BLOOD FLUKE Schistosoma
Adult worms mature & reproduce in blood vessels; eggs travel to intestines or bladder
Immature worm burrows through skin into blood vessels
Larvae grow tails and leave snail
Eggs leave body in urine or feces
Larva hatches from egg & infects snail (intermediate host)

12. PARASITIC FLATWORM Schistosoma
NOT IN USA but infects over 250 million people worldwide
Worms can block blood vessels to organs causing irritation, bleeding, tissue decay
= __________________
SCHISTOSOMIASIS

13. TAPEWORMS PARASITIC FLATWORM (lives in HOST animal intestines)
Dog tapeworm
PARASITIC FLATWORM (lives in HOST animal intestines)

14. Attaches with SCOLEX
Head with suckers and hooks to help hold on inside host

15. TAPEWORM NO DIGESTIVE SYSTEM -absorbs nutrients through skin
TEGUMENT protects them from host digestive enzymes and immune system

16. PROGLOTTIDS hermaphroditic reproductive structures
TAPEWORMS
PROGLOTTIDS hermaphroditic reproductive structures
(contain both male & female sex organs)
EGGS INSIDE

17. TAPEWORMS Can grow up to 30 ft (2000 proglottids)
TAPEWORMS
Can grow up to 30 ft
(2000 proglottids)
Add new proglottids behind scolex
Mature ones drop off at tail end and leave body in feces

18. EX: BEEF TAPEWORM Adults attach inside intestines and absorb
digested food
Humans eat undercooked meat
containing cysts
Proglottids burst releasing eggs with larvae inside on ground
Proglottids are released in feces
Cows eat grass; larvae travel through blood vessels;
make cysts in muscle

19. ROUND WORMS Nematoda Ascaris Trichinella Hookworms Pinworms
Filarial worms
ROUND WORMS ARE PSEUDOCOELOMATES

20. Ascaris Lives in intestines Feed on passing food PARASITIC ROUND WORM
Females can grow up to 1 ft long & produce 200,000 eggs/day

21.     ASCARIS LIFE CYCLE
Larvae are coughed up & swallowed; Return to intestines, mature, & mate 
Eggs leave body in feces and enter new host in contaminated food/water   
Develop into larvae and burrow through wall into blood vessels

22. Most common worm infection world wide
Most common worm infection world wide
Mostly in children
Estimated 25%
of world’s
population is infected
with Ascaris

23. PARASITIC ROUND WORMS Trichinella
Cysts release larvae that burrow into intestinal wall & mature
Humans infected by eating undercooked meat containing cysts  
Larvae forms cysts in muscle
Adults release larvae that travel through bloodstream to muscles 

24. PARASITIC ROUND WORMS Trichinella – TRICHINOSIS-
Larvae leave intestine and travel through blood vessels to muscle where they make cysts
Muscle pain & stiffness can be fatal if cysts form in heart
= _______________________
TRICHINOSIS-

25. TRICHINOSIS Less than 100 cases/year in USA from PORK
Most from eating wild game
Curing (salting), drying, smoking, or microwaving meat does not consistently kill infective worms.

26. FILARIAL ROUND WORMS
are transmitted by insects

27. FILARIAL ROUND WORMS Elephantiasis
Adult worms live in lymph nodes causing blockage so fluid back ups

28. ELEPHANTIASIS Common in tropical countries
Adult worms can grow to 4” long

29. ELEPHANTIASIS

30.   Mosquito picks up larvae from blood when it feeds
Larvae develop into juveniles inside mosquito
Mosquito injects juveniles which migrate to lymph nodes and mature
Adult worms live
and reproduce in
lymph vessels  

31. FILARIAL ROUND WORMS DOG HEARTWORM Carried by mosquitoes

32. FILARIAL ROUND WORMS Loa loa
Found in AFRICA

33. Loa Loa worm Humans are infected with larvae when bitten by loa fly
Larvae mature & crawl around under skin (especially near face)
Adults mate and produce larvae which can be picked up by another fly and transmitted to another person

34. PARASITIC ROUND WORMS Guinea worm
Found in AFRICA

35. PARASITIC ROUND WORM Guinea worm 
Blisters pop and larvae are released in water 
Female bodies under skin fill with eggs and break open; larvae form blisters
Larvae eaten by small crustaceans Humans infected by drinking water  
Larvae mature and adult worms migrate to skin

36. PARASITIC ROUND WORMS Hookworms
Live in intestine;
feed on BLOOD
Ancylostoma

37.      HOOKWORM LIFE CYCLE Return to intestines; mature & mate
Larvae are coughed up & swallowed;   
Adult worms live in intestine and feed on blood
Larvae enter body by burrowing through skin on feet & travel to lungs  
Eggs leave body in feces and hatch as larvae in soil

38. Hookworms in Humans PROBLEMS caused by migrating larvae
Cause intense reaction in skin at site
Infect 40 million people worldwide

39. Parasitic ROUND WORMS Pinworms
Most common parasitic infection in United States
1/5 children are infected
Worldwide 500 million people are infected with pinworms
Grow up to ½ inch long

40. Parasitic ROUND WORMS Pinworms
Worms live in intestine
Females crawl out through anus at night and lay 15,000/day eggs on skin
Intense itching causes host to scratch
Eggs under fingernails and on hands are spread back to self or to others when objects/food are touched

41. SEGMENTED WORMS Annelida
FREE LIVING PARASITIC
Earthworms Leeches
SEGMENTED WORMS ARE EUCOELOMATES

42. LEECHES
Medical uses