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