worms what’s eating you for dinner ?. flatworms phylum: platyhelminthes free living parasitic...
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Worms
What’s Eating You for Dinner ?
FLATWORMSPHYLUM: Platyhelminthes
FREE LIVING PARASITIC
Planaria Flukes & Tapeworms
FLATWORMS ARE ACOELOMATES
PARASITIC WORMS
Animal host where ADULT feeds and reproduces = PRIMARY HOST
Animal host where LARVAL formlives and feeds = INTERMEDIATE
HOST
HUMAN BLOOD FLUKESchistosoma
Larva hatches from
egg & infects snail(intermediate host)
Eggs leave body in urine or feces
Adult worms mature & reproduce in blood vessels (PRIMARY HOST) ; eggs travel to intestines or bladder
Larvae grow tails and leave snail
Immature worm burrows through skininto blood vessels
PARASITIC FLATWORMSchistosoma
Eggs can block blood vessels to organs causing irritation, bleeding, tissue decay
= __________________SCHISTOSOMIASIS
http://www.coc.org/focus/food/pics/rice_paddy.jpg
TAPEWORMS
PARASITIC FLATWORM (lives in HOST animal intestines)
Dog tapeworm
TAPEWORM
Attaches by scolex and absorbs nutrients through skin
Tegument protects them from host digestive enzymes and immune system
CUTICLE-NON-CELLULARcoating made by cells
COVERING for PROTECTION
TEGUMENT- CELLS fused together like armor
Tapeworm SCOLEX
Head with suckers and hooks to help hold on inside host
TAPEWORMSPROGLOTTIDS
hermaphroditic reproductive structures
(contain both male & female sex organs)
EGGS INSIDE
TAPEWORMS
Can grow 30-50 ft (2000 proglottids)
Add new proglottids behind scolex Mature ones drop off at tail end and
leave body in feces
BEEF TAPEWORM
Adults attachinside intestinesand absorbdigested food
Proglottids arereleased in feces
Proglottids burst releasing eggs with larvae inside on ground
Cows eat grass; larvae travel through blood vessels;make cysts in muscle
Humans eat undercooked meatcontaining cysts
http://net.unl.edu/wonderwise/12parasi/a-para.htm
Intermediate host
Primary host
ROUND WORMS PHYLUM: Nematoda
Some FREE LIVING PARASITIC
ROUND WORMS ARE PSEUDOCOELOMATES
Ascaris TrichinellaHookwormsPinwormsFilarial worms
PARASITIC ROUND WORM Ascaris
Lives in intestines ofhumans, pigs, horses
Feed on passing food
Females can grow up to 1 ft long & produce 200,000 eggs/day http://www.biosci.ohio-state.edu/~parasite/images.html
Develop into larvae and burrow through wall into blood vessels
Eggs leave body in feces and enter new host incontaminated food/water
Larvae are coughed up & swallowed;Return to intestines; mature & mate
http://www.extension.iastate.edu/polk/health/carbon/fact3.htmhttp://www.biosci.ohio-state.edu/~parasite/lifecycles/trichinella_lifecycle.html
ASCARIS LIFE CYCLE
PARASITIC ROUND WORMSTrichinella
Cysts release larvae that burrowinto intestinal wall &mature
Adults release larvae that travel through bloodstreamto muscles
Larvae forms
cysts in muscle
http://jeggeri.pri.ee/Kontuur/Loomad/pig.gif http://www.biosci.ohio-state.edu/~parasite/lifecycles/trichinella_lifecycle.html
Humans infected by eating undercooked meat containing cysts
Intermediate host
Primary host
PARASITIC ROUND WORMS
Trichinella – Larvae leave intestine and travel through
blood vessels to muscle where they make cysts
Muscle pain & stiffnessCan be fatal if cysts form in heart
= _______________________TRICHINOSIS-
PARASITIC ROUND WORMS
EX: DOG HEARTWORMCarried by mosquitoes
FILARIAL WORMS
larvae are carried by insects
FILARIAL ROUND WORMS
Elephantiasis Adult worms
live in lymph nodes causing blockage so fluid back ups
ELEPHANTIASISCommon in tropical countries
Adult worms can grow to 4” long
ELEPHANTIASIS
http://www.acm.uiuc.edu/sigbio/project/updated-lymphatic/lymph3.html
Adult worms live and reproduce inlymph vessels
Mosquito picks up larvae from bloodwhen it feeds
Larvae develop into juveniles inside mosquito
Mosquito injects juveniles whichmigrate to lymph nodes and mature
FILARIAL ROUND WORMSGuinea worm
PARASITIC ROUND WORM Guinea worm
Female bodies under skin fill with eggs and break open; larvae form blisters
Blisters pop and larvae are released in water
Larvae eaten by small crustaceans
Humans infected by drinking water
Larvae mature and adult wormsmigrate to skin
FILARIAL ROUND WORMS Loa loa
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
PARASITIC ROUND WORMS
Hookworms
Ancylostoma
Eggs leave body in fecesand hatch as larvae in soil
Larvae are coughed up & swallowed;
http://www.extension.iastate.edu/polk/health/carbon/fact3.htmhttp://www.retiredgreyhounds.co.uk/page12.htm
HOOKWORM LIFE CYCLE
Adult worms live in intestine and feed on blood
Larvae enter body by burrowing through skin on feet & travel to lungs
Return to intestines; mature & mate
http://www.barefooters.org/1995-spring/gifs/mtn_pjl_feet.jpg
Hookworms in Humans• PROBLEMS
caused by migrating larvae
• Cause intense reaction in skin at site
• Infect 40 million people worldwide
PARASITIC ROUND WORMSPinworms
• Most common parasitic infection in United States
• 1/5 children are infected
PARASITIC ROUND WORMSPinworms
• Worms live in intestine
• Females crawl out through anus at night and lay 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
SEGMENTED WORMS PHYLUM: Annelida
FREE LIVING PARASITIC
Earthworms Leeches
SEGMENTED WORMS ARE EUCOELOMATES
LEECHES
Medical uses