imunology - week 3 - parasites 1 Flashcards
Who is the definitive host?
Host in which the sexual stage of a parasite life cycle occures
What is: Mutualism? Commensalism? Parasitism?
Mutualism: benefits both Comensalism: benifets one and neutral for the other Parasitism: benefits one and harmful for the other
Who is the intermediate host?
Host in which asexual reproduction or development occurs
Who is the incidental or accidental host?
The host is not an obligate part of the parasite life cycle
Who is the reservoir?
Animal hosts that maintain the natural cycle in the wild, often not really harmed
Who is the vector?
A host species that transmits an infectious form of the parasite to another host species (ex. mosquitoes transmit malaria)
What are the two Platyhelminthes? (2)
Cestoda (tapeworms) Trematoda (flukes)
What are the physical characteristics of Tapeworms? (2)
1) Flattened segmented bodies 2) No internal digestive system, nutrients absorbed across cuticle
What are the physical characteristics of Flukes?
1) Broad flattened bodies 2) Simple digestive system with a single opening for mouth and anus
What is taeniasis? Cause? Location?
1) Caused when you eat undercooked pork 2) Tapeworm is in intestine
What is cysticercosis? Cause? Location?
Cause: caused by eating tapeworm eggs location: larva in muscle, eyes and brain
What is Taenia solium?
Pork Tapeworm
What is Taenia Seginata?
Beef Tapeworm
Who is the defnitive host for tapeworms?
Humans
Who is the intermediate host for tapeworms?
Pigs, humans (cows for beef tapeworms)
What is the pathology of Taeniasis?
asymtomatic or causes abdominal discomfort, occasionally nausea, vomiting, diarrhae, weight loss and obstruction
What is the pathology of Cysticercosis? (2)
1) muscle may cause lumps but usually no symptoms 2) brain cause neurocysticercosis: confusion, difficulty with balance, brain swelling, mortality
How do you diagnose pork or beef tapeworms? Self? Clinical?
Self: active proglottids Clinical: eggs in stool
How do you prevent beef or pork tapeworm?
Well cooked or freezing
What is Diphyllobothrium latum?
Fish tapeworm
What is the intermediate host of fish tapeworm? (2)
copepod infects fish
What is Echinococcosis?
dog tapeworm
How do you get Echinococcus?
Eat the eggs from dogs
What is the definitive host for Echinococcosis?
Wild and domestic dogs
What is a Hydatid cyst?
Parasitic infection from Echinococcosis
What is Schistosomiasis?
Blood flukes
What are three types of Schistosomiasis?
Schistosoma mansoni Schistosoma japonicum Schistosoma haematobium
Where do you find the eggs for schistosoma mansoni?
Feces
Where do you find the eggs for schistosoma japonicum?
feces
Where do you find the eggs for Schistosoma haemotobium?
urin
What causes the major symptoms for Schistosoma?
eggs become trapped in terminal portal venules where they incite chronic inflammation
Which parasite has a major indictaion for liver cancer? (2)
Schistosoma mansoni and japonicum
Which parasite has major indications for bladder cancer?
Schistosoma haematobium
How is schistosoma transmitted?
Contact with water containing cercaria (snail)
What causes swimmers itch?
duck schistosomiasis - inflamatory response to their eggs
Where is S. mansoni found?
tributaries of african rivers caribbean brazil
Where is S. haematobium found?
tributaries of african rivers
Where is S. japonicum found?
standing water, rice paddies and lakes (lots in china)
What is the lifestyle of Schistosome
1) males and females attached together in host 2) male pulls in nutrients 3) female pumps out eggs (1000/day)
What is the structural identification of S. Mansoni?
Lateral spike
What is the structural identification of S. haematobium?
Terminal spike
What is the structural identification of S. japonicum?
No spike
What is the morphology of cerecarial?
head part and tail part, head part stays when it burrows into skin
What is the pathology of schistosoiasis? Early? Middle? Chronic?
Early: 0-2 weeks, no symptoms, maybe rash Middle: 1-2 months, katayma syndrom chronic: 5-15 years: continually produce eggs so theirs chronic inflammation, liver and colon cancer, bladder cancer
What is Katayama syndrome? When does it occur?
Schistosamiasis eggs cause an intense immune reaction or cytokine storm. patient has hyperactive immune system, fever etc… When: 14-84 days after Schistosamiasa infection
How are Pinworms transmitted?
Ingestion of eggs, direct person to person
What is the lifecycle of Pinworms? (4)
1) Females emerge from anus at night to lay eggs 2) Eggs in bedclothes 3) eggs swallowed and hatch in intestine, 4) adults mate and migrate to colon
What is the pathology of Pinworms? (4)
Intense anal intch (from anus) Secondary infection from itching urogentital invasion in females trauma
How do you diagnose Pinworms?
“scotch tape test” put scotch tape over anus and check for eggs
How do Whipworms transmitted?
ingestion of embroyonated eggs
Where do Whipworms attach to?
colonic mucosa
What is the lifestyle of whipworms?
1) eggs mature in soil for around 10 days 2) Eggs swollowed and hatch in intestine 3) adults mate and migrate to colon 4) eggs passed in feces
What is the pathology of whipworm? (2)
1) low level blood and diahhrae 2) chronic malnutrition
How do you diagnose whipworm?
eggs in stool
Where does Ascariasis infect?
upper intestine
What is the lifestyle of Ascariasis?
1) females lay 200,000 eggs 2) eggs mature in soil for 3 weeks 3) eggs are swallowed 4) larvae hatch and invade intestinal mucosa 5) They enter venous circulating to lung 6) larvae are coughed and swallowed again 7) they mature and mate in small intestine
What is the pathology for Ascariasis? (2)
1) chronic malnutrition and poor mental and physical development 2) can cause allregic inflammation during migration through lungs
Where do Hookworms go?
Small intestine
How are hookworms transmitted?
invade skin from soil, not person to person
What is the lifecycle of Hookworms?
1) Larvae mature in soil 2) enters humans from soil through skin 3) goes into circulation and gets lodged in the lung 4) coughed up and swallowed 5) mature and go to small intestine
What is the pathology of Hookworms? (2)
1) itching and swelling sometimes at site of entrance in skin 2) chronic malnutrition
Where do Strongyloides go?
Small intestines
What is the lifecycle of Strongyloides?
1) adults lay eggs in intestinal mucosa and they hatch there 3 ways: (depends on soil and immunity of host) 1) Larvae can infect a host directly from feces: they have a lung stage here 2) GOOD SOIL VERSION: If soil is conducive, larvae can go through development in the soil and mate and produce more larvae 3) BAD IMMUNE SYSTEM VERSION: Larvae can reinfect the host from the intestine themselves
What is the pathology of Strongyloids? (2)
1) Pulmonary issues and chronic malnutrition 2) auto infection and immunosuppression leads to hyperinfection that can be fatal
How can you diagnose Strongyloides? (2)
1) Larvae in stool 2) Larvae in sputum
Where does Trichinosis live? Adults? Larvae?
Adults live in small intestine Larvae live in muscle
What is the lifecycle of Trichinosis?
1)
How is Trichinella transmitted?
By eating undercooked meat (pork) containingq encysted larvae
What is the lifecycle of Trichinella?
1) larvae are released in the gastric environment 2) adults develop and mate in small intestine 3) male dies, female embeds in mucosa 4) live larvae birthed without eggs, female dies 5) Larvae enter lympatics/blood and encyst in muscle 6Larvae develop into encapsulated sprial and are vialbe for up to 10 years
How long are encysted Trichinella larvae viable?
up to 10 years
Who is the intermediate and definite host for Toxacariasis?
dogs
How is Toxocariasis transmitted?
Ingested from soil, no human to human transmission
What is the lifecycle of Toxacara canis?
1) Sexual cycle that produce eggs in feces 2) larvae can encyst in tissues and infect puppies in utero 3) humans infected by ingestion of eggs from dogs 4) in humans, larvae burrow through intestine and wander for months in any tissue
Who are the accidental host of Toxocariasis?
humans
What is the pathology for Toxocariasis? (2)
chronic malnutrition and neurological symptoms
How do you diagnose Toxocariasis?
History of geophagia (eating dirt) and exposure to dogs No eggs in stool
Where is Strongyloides distrubuted?
Warm places, United states and elsewhere
