Multicelluar Eukaryotic Parasites Flashcards
What are metazoa?
Parasitic worms
What is an Endoparasite?
Live inside the body, and often have complex life cycles with several hosts ie) tapeworms, roundworms
What is an ectoparasite?
Like on the body (typically only when feeding). Can serve as vectors for other pathogens. Ie) leeches, ticks
Give some examples of Helminthes
1) platyhelminthes (flat worms)
- > cestodes (tapeworms) ie) Taenai
- > Tremtodes (flukes) ie) Schitosoma
2) Nematoda (unsegmented roundedworms) eg) Ascaris
3) Annelida (segmented roundworms) ie) Hirundinea (leeches)
What is a definitive host
Where an organism reproduces sexually
What is an intermediate host
Where an organism may develop but doesn’t reach sexual maturity. May reproduce asexually or not at all
What is taeniasis?
Tapeworm infection
What is Taenia saginata?
Beef tapeworm. Humans are the definitive and cattle are the intermediate host.
What is Taenia saginata lifecycle?
1) immature tapeworm if found encysted within the muscle of cow (usually jaw/tounge)
2) the cyst is consumed by human (meet not cooked properly.
3) the worm grows into adult forms inside human small intestine.
4) the worm fertilizes itself and releases its eggs in human feces. (Which is used to fertilize crop)
5) Eggs are consumed by cow, hatch, migrate to tissues to develop into cysts.
How does the adult tapeworm reproduces? Specifically Tanenia saginata
The adult worm has both ovaries and testies and self fertilizes. The eggs are released into feces.
What is a scolex?
Head (tapeworm) has suckers and hooks.
What is a proglottids?
A body segment of a tapworm.
Each contains ovaries and testis and is filled with eggs and are shed with feces.
What is Taenia solium?
Pork tapeworm
What happens in the intermediate host of Taenia solium?
In the intermediate the eggs hatch and the larvae migrate to other tissues. If enters normal muscle no issue, will form a cyst called Cysticerci. If moves into a speciality like eye, heart, brain spinal cord very serious can cause Cysicercosis.
What are the two main hosts in a fluke (trematode) life cycle?
Definitive host is a vertebra and intermediate is usually a snail.
Typically leaf shapped
What is an example of a fluke?
Clonorchis sinensis.
Lifecycle includes snails, fish and humans.
What is Paragonimus westermani?
It’s a human lung fluke. Lifecycle includes snails, crustaceans and humans
What are blood fluke?
Schistosoma. Penetrates human skin, (definitive host) where eggs are shed in feces/urine. Eaten by aquatic snails. (Intermediate)
What is swimmer’s itch?
Cercarial deratitis. It’s a species of Shistosoma in which the deck is the definitive host. The Laraval form penetrates the skin but soon dies
Give an example of a nematode (non-segmented round worm)
Trichinella spiralis.
How lg are nematodes (non-segmented round worms)
Vary from 1mm-1m
What is a pin worm?
It’s a type of nematode (specifically Enterbius vermicularis)
What is the life cycle of Enterobius vermicularis?
Oral fecal.
Migrates to anus and lays eggs->itchy and scratch. Can self infect or transfer to new host
What is a hookworm and give some examples
A hookworm is a form of nematode. Ie) Neactor americanus & Ancylostoma anemia
How do hookworms enter their host?
They can crawl and penetrate skin-> get into blood-> lungs-> digestive track and lay eggs
What do hookworms look like
Like a bic pen
What is Ascaris lumbricoides?
The “giant intentional roundworm’
How do you become infected with Ascaris lumbricoides?
Eggs from feces ends up in the soil. Ingested from unwashed fruits and veggies.
What happens once Ascaris lumbricoides is ingested?
It penetrates the gut->lungs-> digestive tract.
What is the danager with a heavy infection of Ascaris lumbricoides?
A heavy infection can lead to intestinal blockage. Also migrating larvae may cause pneumonia
How are Filarial worms transmitted?
By mosquitoes.
What disease does Filarial worms cause?
Elephantiasis
What is an example of Annelida (segmented round worms)?
Hirudinea (leeches)
What are some examples of lice?
Pediculus capitis (head lice) Pediculus humanus (body lice->clings to clothes) Phthrius pubis (pubic lice->crabs)
What does a Bot fly do?
They lay eggs on body typically in open wounds. The larvae (maggots) live off of tissue and secretions.
What classification do mites belong to?
Arachnida (as well as ticks)
What is the difference between scabies and chiggers?
Both are caused by mites. In Scabies they tunnel through skin to lay eggs. In Chiggers the larval mites burrow into skin and die
