Topic 5 Post Midterm 1 Flashcards
What are flatworms also known as?
Flukes (Trematodes)
Name the 4 features of flukes
- flat leaf shaped bodies
- suckers for attachment
- covered in cuticle for protection
- no segmentation
Where do flukes live?
Inside another organism (ex: inside an animal or human - may live in the intestine or circulatory system)
Name two components of the fluke
oral sucker and intestine
What is the other name for an asian liver fluke?
Clonorchis sinensis
How many hosts do flukes have?
2 intermediate hosts (primary and secondary)
What animals do the lifecycles of flukes contain?
- Snails
- Fish
- Humans
What is the lifecycle of flukes? (6)
- Embryonated eggs passed in feces (diagnostic stage)
- Eggs are ingested by the snail
- Free-swiming cercariae encyst in the skin or flesh of fresh water fish
- Metacercariae in flesh or skin of fresh water fish are ingested by human host (infective stage)
- Excyst in duodenum
- Adults in biliary duct
What is clonorchiasis?
Infection of Clonorchis
- live in the bile duct
- may not be a problem
- if you have quite a few they eat the bile and you can have digestive issues
What are S+S of clonorchiasis?
- Jaundice
- N/V
- Diarrhea
- Abdo pain
- Liver enlargement
What do liver flukes infect?
Ruminants (including goats, moose, sheep, etc)
What does the life cycle of a liver fluke include?
A snail and mammal (most of them) or a fish
Describe how the liver fluke is passed
- The goat eats the larvae with the grass
- The larvae grow into adult liver flukes that are found in the liver of the goat
- The adult liver fluke lays eggs which pass out in the dung
- A larva hatches from the egg
- The larva swins, infects a special type of snail and develops through various stages
- The final larval stage leaves the snail and swims
- The final larval stage attaches to grass or plants
What are human lung fluke missing?
Reproductive organs
What does the lifecycle of human lung fluke include?
- Snails
- Crustaceans
- Humans
What are the 8 steps of the human lung fluke lifecycle?
- Hermaphroditic adult fluke releases eggs into human lung
- Eggs reach water after being excreted in feces
- Miracidium develops in egg and hatches from egg
- Free-swimming miracidium enters snail
- Inside snail, miracidium develops into redia, which reproduces asexually to reproduce rediae; several cercaria develop within redia
- Cercaria leaves snail and enters crayfish
- In crayfish, cercaria encysts to produce metacercaria
- Infected crayfish is eaten by humans, and metacercaria develops into adult fluke
What is the definitive host in a human lung fluke?
Human
What is the intermediate host in the human lung fluke?
Crustaceans and snails
What is the other name for Blood fluke?
Schistosoma sp
What host is the human in a blood fluke?
The definitive host
Where are eggs shed in the blood fluke?
In feces and urine
What does the larval stage do in blood fluke?
It parasitizes aquatic snails
What blood vessel do blood flukes attach to?
Large blood vessels (ex: hepatic blood vessel)
- It sticks itself into that blood vessel and takes oxygen from blood and takes some blood too
What is the intermediate host in blood flukes?
Snail
How do blood flukes reproduce inside the snail?
Asexually
What happens with blood flukes inside the body?
There are male and female hosts that live within the definitive host and attach to the inside of the blood vessel, the male and female attach to each other. They are constantly having sex and making eggs inside the human. They are embroyinated eggs
What is the infective stage in blood flukes?
Step 5: While Cercariae is released by snails into the water and are free-swiming
What is the diagnostic stage in blood flukes?
Worms in the feces and Urine
What is the lifecycle of blood flukes? (10)
- ?
- Eggs hatch releasing miracidia
- Miracidia penetrate snail tissue
- Sporocysts in snail (successive generations)
- Cercariae released by snail into water and free-swimming
- Penetrate skin
- Cercariae lose tails during penetration and become schistosomulae
- Circulation
- Migrate to portal blood in liver and mature into adults
- Paired adult worms migrate to:
- mesenteric venules of bowel/rectum (laying eggs that circulate to the liver and shed in stools)
- venous plexus of bladder
What is the definitive host in swimmers itch?
A duck
What is the accidental host in swimmer’s itch
A human (a parasite can’t survive/reproduce in)
What is the 5 stages in the life cycle of the Swimmer’s Itch?
- Eggs are passed in feces
- Eggs hatch and liberate miracidia
- The parasite develops in a mollusan intermediate host
- ?
- Humans are exposed to the dermatitis-producing cercariae
- Cercariae penetrates the skin of the birds and migrate to blood vessels to complete the cycle
Swimmer’s Itch symptoms
Little or no symptoms, some have a violent allergic reaction
What is the other name for nematodes?
Unsedmented Roundworms
Give details about nematodes
- Shed exoskeleton or cuticle during growth
- Free-living or parasitic
- Don’t have segments
- 1mm-1m in length
Ex: Leeches
What is another term for pinworm?
Enterobius vermicularis
What disease is associated with pinworm?
Enterobiasis (pinworm infection)
What is another term for large intestinal roundworm?
Ascaris lumbricoides
What disease is associated with large intestinal roundworm?
Ascariasis
What is another word for hookworm?
Necator americanus
What disease is associated with hookworm
Hookworm infection
Where are Nematodes (Pinworms) found?
Adults live in the lower intestine tract
- Migrate to the anus to lay eggs (female) during the night
What type of issues do Pinworms cause?
Not major issues
Where are the eggs of pinworms transferred to?
Eggs (containing larva) are transferred to new host
What is the lifecycle of the pinworm? (5)
- Eggs on perianal folds. Larvae inside the eggs mature within 4-6 hours
- Embryonated eggs ingested by human
- Larvae hatch in small intestine
- Adults in lumen of cecum
- Gravid migrates to perianal region at night to lay eggs
What is the infective stage of pinworms?
Step 2 when it is ingested by the human
What is the diagnostic stage of pinworms?
Step 1 when the eggs are on perianal folds
How can you get Trichinella?
Ingesting cysts in poorly cooked meat
How common is Trichinella?
Not as common as it used to be
What is the name for pork worm?
Trichinella
What is the infection caused by pork worm?
Trichinosis
Where do the adults mate in pork worm?
Small intestine
Where do the larvae move to in pork worm?
To lymph and blood vessels and encyst in muscles
Pork worm lifecycle
____ slide 34
Describe Ascaris lumbricoides
Eggs from feces end up in the soil and are ingested with unwashed fruits and vegetables
- Larvae migrate to lungs and then back to intestines
What is the lifecycle and i/d stage of Ascaris lumbricoides?
___ slide 35
Ascaris causes what type of infection?
Ascariasis
Describe the infection causes by ascariasis
May be asymptomatic or may cause diarrhea
- Severe infections may block intestine
- Migrating larvae may cause pneumonia
How is the tip of a male and female ascaris different?
The female end is straight while the males is round
How do you get rid of ascaris?
Removed surgically
Lifecycle Guinea worm?
slide 39
How can you avoid getting Guinea worm?
By using filters to remove copepods in the water
Where are Filarial Worms found on earth and on a human?
- Mostly topical places
- Bury under the skin
How are larvae transmitted in filarial worm?
By mosquitoes
What can filarial worm cause?
Elephantiasis
What is the size of filarial worms?
Very small
What is the intermediate host of Filarial worms?
Mosquitoes, they live out part of their life in a mosquito
Life cycle filarial worm
slide 41
How can you treat elephantiasis
Mimics edema
- If it is treated early, it can be corrected
- If it is severe, it will need cosmetic surgery and be expensive
What worms can be used therapeutically?
Trichuris suis (“whipworm”) have been proposed as treatments for Crohn’s disease and autoimmune disorders
What is another name for leeches?
Hirudinea
What is another name for segmented round worms?
Annelida
What are used for segmented round worms and leeches in the world?
Medicine:
- Release anti-coagulants and local anesthetic
- Can be used to encourage blood flow into reattached appendages and tissue grafts
Name a type of anthropod
Insects
What are the 3 species that infect humans?
- Pediculus capitis - head lice
- Pediculus humanus - body lice
- Phthirus pubis - pubic lice “crabs”
How do you get rid of body lice?
Easy to get rid of them, you wash your clothing
How can you kill lice?
Get rid of the eggs and the adults with a fine-toothed comb
- Use vinegar
Where do body lice live on?
Clothing
What do lice feed on?
Blood
Where do bot fly (insects) live?
Females lay eggs on body - usually in open wounds
- Can live under the eye or in a wound
What do larvae feed on (in terms of bot fly)
Tissues and secretions
*not a very common thing to have B.F
What do bedbugs feed on?
Blood
Give 3 facts about bedbugs
- May remain dormant for many months
- The bites itch and can cause allergic reactions
- Do not appear to be common disease vectors or pathogens
Where are mites found?
Burrowing in human skin
What is the scientific term for scarbies mites?
Sarcoptes scabiei
Give 3 facts about mites (Arachnids)
- Tunnel through skin
- Similar to mites which cause mange in pets
- Cause irritation, feces may cause allergic reaction
What are chiggers (mites)
- Larval mites burrow into skin and die
What do chiggers affect?
Large mammal (ex: deer)
What do chiggers cause?
Inflammation and allergic reaction
What type of animal are dust mites
Anthropods - Arachnides (Mites)
Describe dust mites (3)
- Are not parasitic
- Feed on dust (mostly dead skin) and bedding around the house
Feces and moults (shed exoskeleton) become airborne and may cause allergic reactions
What type of insect can you use in therapy?
Maggots can be used to heal diabetes wounds to clear dead tissue from chronic wounds in diabetics
What are maggots?
Larva of flies
