Helminths Flashcards
What are helminths?
intestinal nematodes
What helminth (intestinal nemotods) is transmitted fecal orally, with females worms that migrate to the anus, lay their eggs => causing it to be V itchy?
Eterobius vermicularis (pinworms)
What helminth is common in the rural southren USA by walking BAREFOOT?
- Necator Americanus
2. Ancyclostoma duodenale
What helminth is a large worm that infects ppl by eating food/water contaminated with their eggs?
- Ascaris lumbricoides
Which helminth is most common in hot/humid climates and penetrate the skin at the bottom of the feet?
Strongyloides stercoralis
Which helminth is contracted by eating its cysts in undercooked meat, like pork or bear?
Trichinella spiralis
What our types of roundworms (nematodes)
- Intestinal
- blood and tissue
- Cutneous larval migrans
Which intestinal roundworms do we get by consuming their eggs
- Ascaris lumbricoides
- Trichuris trichura (whipworm)
- Enterobius vermicularis (pinworm)
What is trichuris trichura (whipworms)
nematode (helminth)/roundworm that we get by ingesting eggs
eggs hatch in GI tract => cecum and LI, slow life cycle; mature adults thousands of eggs/ year
=> abdominal pain and diarrhea
Dx trichuris trichura (whipworms)
ID eggs in poop; look like footballs with bumps on each end
What are our tissue nemotodes (helminths)/ roundworms?
- Dracunculus medinesis
- Wuchreria bancrofti
- Brugia malayi
- Onchocerca volvulus (river blindness)
How are our blood and tissue roundworms spread?
Blood sucking arthropods, which then pick up microfiliarie and transmit to humans
What family to blood and tissue roundworms belong to?
Filarioidea, so they’re filariae
Adult filariae live where and give rise to what?
Lymphatic tissue
give rise to microilariae (pre-larval forms) that do not lay eggs. They bury in tissue and circulate in the blood and lymph system.
How do blood and tissue roundworms (filarioidea) cause disease?
allergic reactions to microfiliaer and dead adult worm
Wucheria bancrofti and bulgai malayi are both tissue/blood roundworms that cause lymphatic infections => elephantitis. What is the difference between the 2?
- Wucheria is endemic to Pacific Islands and Africa
2. Brugeria is endemic to Malay peninsula and SE Asia
NAme that blood/tissue hemlminth roundworm or filaridea:
Matt drinks water that is contaminated with African/Asian freshwater copepods that have larvae this roundworm.
The roundworm will then go into our GI tract => penetrate the skin => subcutaneous tissue, where adult F will emerge from a painful ulcer, exposing her uterus. When the person comes in contact with water, F releases larva.
Drancunculus medianesis;
Name that blood/tissue helminth roundworm or filaridea:
Black fly, in Africa/Central/South America, contains the larva of this roundworm. The larvae then bury into hosts => become adults and make microfilarial that migrate around the body, causing a puritic skin rash with dark pigmentation => form intraepithelial granulomas.
If this microfilarae goes to the eye, it can cause blindness
Onchocerca volvulus (river blindness)
What are the 2 most common causes, in order, of infectious blindness
- Chylamdia trichmonosis
2. Onchocerca volvulus
What are cutaneous larval migrans?
Larva of hookworms from cats or dogs in the SE USA that go into skin and migrate RIGHT BENEATH EPIDERMIS; you can see outline of em. Move a few cm a day => allergic rxn =>? red itchy rash that moves
They can be: dog hookwork (ancyclostoma branzilense) and necactor americanus and strongyloids stercalis
platyhelminthes are what?
flatworms
What are out 2 platyhelminthes
- Trematodes (flukes)
2. Cestodes (tapeworms)
Trematodes are a flatworm that include freshwater dwelling schistosomes.
Which sex mates and where?
What is their intermediate hosts?
both mate in humans, but not in GI tract
water snail species => interm hosts
Tapeworms, also called ______, mate where?
how do they reproduce?
Cestodes
Live and mate in human GI tract
Each has M and F organs (hermaphrodies), so they can make bbs by themselves without fucking
How do cestodes (tapeworms) get food?
They do not have a GI tract, so they have to eat nutrients that have been ingested by their host.
What are our cestodes (tapeworms)?
- Taenia solium (Pork tapeworm)
- Taenia saginita (Beef tapeworm)
- Diphyllobrothrium latum (fish tapeworm)
- Echinococcus granulosus
How do humans get taenia soleum (pork tapeworm) ?
ingestion of undercooked pork infected with larvae.`
What is cysticercosis?
What is neurocysticerosis?
Cysticercosis occurs when humans consume the EGGS, rather than larva/cysticerus. Eggs hatch in SI => larva migrate and go into tissue and form cysticerci. This often happens in the brain and skeletal muscle.
Cysticerci that develop in the brain from eggs => larva. Cystic brain lesions that cause seizures, obstructive hydrocephalus and focal neuro deficits.
Occurs when people ingest taenia solem (pork tapeworm) eggs and they go to the brain
What happens if someone ingests larva or cysts of tinnea soleum?
Taenisis, which is usually asx, but can cause GI/ malabsorption issues.
Only sxic if eggs are ingested.
Taenia soleum: within the pig, the eggs develop into larvae that do what?
What can then happen in the animals muscle tissue?
Go to intestine and muscle
In animals muscle, the larva can become cysticercus, round, fluid-filled bladder with a larval form inside.
Where is pork tapeworm (taenia solium) endemic?
MX, central and South America, Phillipines and SE asia.
What does neurocysticercosis look like on MRI?
Swiss cheese
On stool O and P, how are taenia solium and saginata different?
Taenia solium have proglattid heads
How is Taeniae saginatta different than taeniae solium?
Same cycle, but we do not develop cysticerci when we ingest eggs. Thus, when infected it is not too bad.
How do we get beef tapeworm?
ingest larval cysticerci in undercooked beef mucsle.
tapeworm can adhere to intestine with proglottid and reach over 10 meters.
What is Diphyllobothrium latum?
freshwater Fish tapeworm from eating undercooked fish.
It can absorb vit B12 (cobalamin) = causing a B12 deficiency => megaloblastic anemia.
What is the largest tapeworm
Diphyllobothrium latum (fish tapeworm) that can grow over 45 meters in length.
How do we diagnose Diphyllobothrium latum?
ID eggs in feces;
on stool O and P we will see, proglottid segments
Echinococcus granulosus
Defimitive host
Intermediate hosts
Sheep tapeworm that we get when we ingest eggs that are in dog shit. Eggs hatch in intestine and become larva. Larva can then go throughout the body, but mostly go to the [liver, lungs, kidney and brain].
Definitive host: dogs
Intermediate hosts: sheep
What does Echinococcus granulosus cause?
Larva form a round, fluid filled HYATID CUSTS
Cysts can compress the organ around it (in liver, lung or brain) and when it ruptures, it causes anaplylaxis because we are extremely allergic to the fluid => could be fatal
What do the hyatid cysts look like on CT?
Eggshell calcifications.
How are Echinococcus granulosus different from E. multilocularis cysts?
E. Granulosus cysts grow larger but only spread if they rupture.
E. multoocularis can undergo lateral budding and spread, and can be misdiagnosed as a slow growing tumor.
How do we treat tinnea soleum and saggiinatum?
Praziquantal
How do we treat diphyllobothrium latum?
Praziquantal or niclosamide
How can we diagnose echinococcus granulosus ?
high eosinophilia
Trematodes are also called what
flukes
What are the only type of flukes are concerned about?
Schistosoma (blood flukes)
Where are schistosomas found?
Intermediate host?
How do they enter the body?
and exit
Freshwater
Snail
Cercariae (mature schistosomal larvae) penetrate exposed skin => enter portal venous blood, moving against it => larva mature into adults and lay eggs, however, the eggs cannot hatch in our body. They can only hatch in freshwater
=>depending on the species => go to veins that lead to intestines or bladder and lay eggs: which can enter lumen of intestine or bladder => feces or urine in freshwater
What are the 3 major disease assx with schistosominasis, that occur SEQUENTIALLY?
- Dermatitis, as it penetradtes the skin: itches and rash
- 4-8 wks later => Katayama fever: as adult lays eggs (fever, hives, HA, WL, cough) for 3 weeks
- Chronic fibrosis of (liver, lung or brain) that occurs as a result of chronic inflammation around eggs, forming a granuloma. depost into wall => fibrosis
Chronic fibrosis of liver, lung or brain d/t schistosomiasis can result in what?
portal HTN
The prion is an infectious agent that can fold in multiple, structurally distinct ways, and in at
least one of those fashions, is transmissible to
other prion proteins, leading to disease that
appears similar in certain respects to _____
infection.
viral
What is prion disease?
Prion diseases are Transmissible Spongiform Encephalopathies.
Occur when normal prion protein (PrPc) misfolds into PrPSc or PrPTSE, making resistant to proteases and making it a insoluble amyloid.
Conversion from PrPc to PrPcSc or PrPTSE results in what
neuronal degeneration
What encodes PrPc?
PRRNP gene on chromosome 20; imp for cell functions, cell adhesion, ion channel, neuronal excitatbility
what is unique baout prion dieases
self-propogating and transmissble
PrPSc is made endogenously or introduced to body and converts normal to abnormal
What are are prion diseases
alzheimers
Parkinsons
ALS
Crutfield Jacob is the MOST COMMON
majority of prion disease are what ?
sporadic
what infleunces susceptibility to prion disease?
Methionine/valine polymorphism at codon 129 of PRNP gene
CJD causes what
dementio
myoclonus
ataxia
neuro abnormalities
What is GSS (Gernstmann-Straussler-Scheiker disease)
inherited prion diases that takes a few years to kill you: causing atxia => dementia
What is FFI (fatal familial insomnia)?
inherited prion diases that takes a 1 year to kill you: sleep problems => dementia
