Worms Friend OR Foe ?

CHARACTERISITCS OF ALL WORMS Invertebrate protostomes Elongated bodies Bilateral symmetry Cephalization Cerebral ganglia “brain” No respiratory organs (Breathe through skin)

WHERE DO THEY LIVE? _______________ - Found in environment _______________ Live on or in another organism FREE LIVING PARASITIC

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

FLATWORMS PHYLUM: Platyhelminthes FREE LIVING PARASITIC Planaria Flukes & Tapeworms

PLANARIA NOT PARASITES

ONE opening digestive system GASTROVASCULAR CAVITY (Combination Digestive & circulatory)

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

REPRODUCTION SEXUAL- HERMAPHRODITES (have both ovary & testes in one organism) but trade with a partner ASEXUAL- can use regeneration to grow a new organism from part of parent worm

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 producing disease called = __________________ SCHISTOSOMIASIS

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

TAPEWORMS PARASITIC FLATWORM that lives in HOST animal intestines Dog tapeworm

TAPEWORM VOCAB ____________- Head with suckers and hooks to help hold on inside host SCOLEX

TAPEWORM VOCAB ___________________- hermaphroditic reproductive structures (contain both male & female sex organs) Contain fertilized eggs Shed in feces PROGLOTTIDS

WORM VOCAB ______________ Thickened PROTECTIVE layer on the outside of worms made of CELLS _______________ NON-CELLULAR PROTECTIVE coating found on the outside of worms TEGUMENT CUTICLE

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

TAPEWORMS Can grow up to 30 ft (2000 proglottids) REPRODUCE WITH PROGLOTTIDS Add new proglottids behind scolex Mature ones drop off at tail end Leave body in feces

EX: BEEF TAPEWORM Adults attach inside intestines and absorb digested food Proglottids are released 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 meat containing cysts

ROUND WORMS Phylum: Nematoda Ascaris Trichinella Hookworms Pinworms Filarial worms

ROUND WORM Ascaris PARASITIC Have a 2 OPENING digestive system Lives in intestines Feeds on passing food

Females can grow up to 1 ft long & produce 200,000 eggs/day Humans become infected when they eat FOOD or WATER contaminated with eggs Image from:

Most common worm infection WORLD WIDE Mostly in children Estimated 25% of world’s population is infected with Ascaris

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

Trichinella Trichinella infection can lead to disease called = __________________ TRICHINOSIS- Symptoms: Muscle pain & stiffness Can be fatal if cysts form in heart

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.

PARASITIC ROUND WORMS Guinea worm Found in AFRICA

PARASITIC ROUND WORMS 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 worms migrate to skin 

FILARIAL ROUNDWORMS are transmitted by insects

DISEASES caused by FILARIAL ROUND WORMS DOG HEARTWORM Elephantiasis Loa Loa - eye worm

FILARIAL ROUND WORMS DOG HEARTWORM Carried by mosquitoes

DISEASES caused by FILARIAL ROUND WORMS Elephantiasis Adult worms live in lymph nodes causing blockage so fluid back ups

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

ELEPHANTIASIS

Adult worms live and reproduce in lymph vessels   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

FILARIAL ROUND WORMS Loa loa Found in AFRICA

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 Live in intestine; feed on BLOOD

Eggs leave body in feces and hatch as larvae in soil    Larvae are coughed up & swallowed; 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 

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

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

Parasitic ROUND WORMS Adult Pinworms 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

SEGMENTED WORMS Annelida FREE LIVING PARASITIC Earthworms Leeches

SEGMENTED WORMS Return nutrients to soil by decomposing dead leaves and organic matter Burrowing allows air and water to penetrate to roots Tunnels loosen soil so roots can grow more easily Earthworms play an important role in soil fertility “intestines of the earth” -Aristotle

PARASITIC SEGMENTED WORMS LEECHES Medical uses