Helminths Flashcards
Ascaris lumbricoides are acquired by ____
Once the eggs are ingested, larvae emerge in the ____, then they travel to the ___ where the grow, then they get coughed up and swallowed again where they travel back to the ____ and finally once they are here for the second time they mature into adults and produce eggs that pass into feces
Mostly asymptomatic, may get abdominal cramping and children can become malnourished
Look for eggs in feces and increased ____ levels in blood
Egg ingestion
Small intestine, lung, small intestine
Eosinophils
Hookworm aka ___are acquired by ____ due to the eggs in soil hatching into _____ larvae that can penetrate human skin
Once penetrated, it travels directly to the ___, where it grows, coughed up and reach the ___ for the first time and then matures into adults here and produces eggs
Diarrhea, abdominal pain, weight loss, possibly iron deficiency anemia, and an intense itching and rash at the site of penetration between the ___ is common… Growth in lung can show infiltrates on chest X ray
Necator Americanus, skin penetration (foot), filariform
Lungs, small intestine
Toes
Strongyloides stercoralis is acquired by ____ and similar to hook-worm, they travel directly to the ____ and then coughed up and swallowed where they then reach the ____ for the first time and mature into adults but they DO NOT produce eggs, instead the produce ____
^** THIS IS DIFFERENT FROM HOOK-WORM AND Ascaris lumbricoides that both produce eggs when mature
The new filariform larvae produced can do 3 things
1) ____ aka penetrate the intestine directly and travel back to the lung to start a new cycle
2) Direct cycle where they pass out in feces, survive in soil, reinfect once stepped on by a human (Pretty much the same thing that Hook-worm does except hookwrom has eggs passed in feces that hatch into filariforms rather than already being a filariform)
3) Indirect cycle where larvae pass through feces into soil, mature IN THE SOIL, produce eggs, hatch into larvae, continue cycle by infecting human
**So this infection will be similar to hookworm with a rash between toes, vomiting, abdominal pain, diarrhea, anemia, weight loss, etc but the way to tell them apart is examining the feces which for S. Stercoralis will have ____ and for hookworm it will have ____
Which infection will cause iron deficiency anemia?
Skin penetration, lung, small intestine, larvae
1) Autoinfection
Larvae, eggs
Nectar Americanus (hook worm since it sucks blood from the wall of the intestine)
Fever, abdominal pain, diarrhea, and MUSCLE ACHES along with increased eosinophils (to show that it is a helminth) is characteristic for ___ infection that is acquired by ___ (ingesting encysted larvae)
^** The muscle aches occur because after the initial intestinal invasion the larvae migrate to the skeletal muscle and become encysted
Trichinella spiralis, eating raw pork (like bacon)
Remember, the eosinophil count is only elevated if helminths move out of the intestine but this is not the case for whipworm aka ____ or pinworm aka ____ since they do NOT leave the intestine
Whipworm is ingested by contaminated food with eggs, eggs hatch in GI tract and migrate to cecum and ascending large intestine where they mature and produce more eggs… Characterized by abdominal pain, diarrhea, etc…
^** So NOOOOOO eosinophilia and eggs look like a ____ with polar bumps
Pinworm also is acquired by egg ingestion, maturing in the cecum and ascending large intestines and traveling to the ____ region causing a characteristic perianal itch
Trichuris trichiura, Enterobius vermicularis
Football
Perianal (PERianal itch = PInworm
Unlike the intestinal nematodes that are spread by fecal contamination, the blood and tissue nematodes are spread via ____ and referred to as ____ (they don’t lay eggs, they give birth to prelarval forms called microfilariae)
** DO NOT CONFUSE THE TERM ____ used to describe larvae that can penetrate skin VERSUS ____ the term used to describe larvae that are transmitted by arthropods
All of the disease manifestations for blood and tissue nematodes are due to ___ reactions to both the microfilariae and dead adult worms in the lymph systems and other organs
Onchocerca volvulus is transmitted via a ___ found in Africa and Central and South America and characterized by what 3 things?
A pruritic ___ with darkened pigmentation, ____ skin (thick, dry, scaly skin due to intraepithelial ____), and river ____*
Arthropods, filariae
Filariform, filariae
Allergic
Black fly
Rash, Lizard skin, River blindness
Rash, Lizard, granulomas, blindness
Wuchereria bancrofti (pacific islands and much of Africa) and Brugia malayi (Malay peninsula and Southeast Asia) are transmitted via a ____ and can cause ___ infections that cause ____ with repeated exposures (swellings of the legs and genitals) that is covered by ___ skin
Small infections only result in acute febrile episodes aka filarial fever associated with headaches, swollen inguinal lymph nodes, etc
Dracunculus medinensis aka ___ worm is found in freshwater copepods (aka tiny crustaceans) and characterized by poking a loop of the females body through the skin to expose the uterus and can cause nausea, vomiting, hives, and breathlessness
Mosquitos, lymphatic, elephantiasis, scaly
Guinea worm
____ larva ___ occurs from a larvae of a dog or cat aka tapeworm that infects a human and causes a raised, red itchy rash the moves with the advancing larvae beneath the epidermis…. Occurs in south-eastern US (Florida, georgia, etc)
^** Also called _____ and can be similar to the rashes seen in Necator americanus and Stronglyoides in humans
Cutaneous larva migrans
creeping eruption
Platyhelminthes are also called ____ and have 2 groups called ____ aka Flukes or ____ aka tapeworms
Blood flukes (means they are part of the trematodes) aka ____ are found in freshwater areas in the tropics and their eggs hatch in the water and find an intermediate host aka a ___ where they mature (now called ____) and are released and now can infect humans
Once in humans (via skin penetration), they travel to veins where they mate and mature and depending on the species they either reside in veins surrounding the ___ or ____
^** S. Japonicum and S. Mansoni surround the ___ and excreted in feces and S. HaematoBium surround the ___ and excreted in urine (THINK B = Bladder)
These flat worms use ___ to invade the hosts immune system
3 clinical manifestations occur, first a pruritic (itchy) rash at site of penetration (aka ___ itch), then ____ fever 4-8 weeks later (fever, hives, headache, weight loss, etc), and finally the hosts immune system against the eggs causes ___ to occur in the liver (portal hypertension), lungs (pulmonary hypertension), and intestines (inflammatory polyps) and walling off the eggs as granulomas
Flatworms, Trematodes, Cestodes
Schistosoma, freshwater snail, Cercariae
Intestine or bladder
Intestine, bladder
Molecular mimicry
swimmers, Khatayama fever, fibrosis
Cestodes aka tapeworms have their most anterior head containing suckers and hooks called the ___ region and the regions that contain the fertilized eggs are called the ____ regions
Pork Tapeworms aka ____ are ingested from undercooked pork with infected larvae
The cycle starts with pigs ingesting the eggs and the larvae develops and migrates into the pigs muscles turning into ____ (encysted larvae), then when humans eat undercooked pork the cysticerci turn into adult tapeworms that produces gravid proglottids and eggs, which pass through human feces back into soil that pigs once again eat and cycle continues
If the humans eat the proglottids and eggs (in feces) rather than the encysted larvae cysticercus form, then ____ can occur causing the eggs to hatch in the small intestine and then the larvae to move to and encyst in the brain, skeletal muscles, or eyes leading to neurocysticercosis (seizures, obstructive hydrocephalus, neurological damage) and blindness
^** Characterized by a CAT scan revealing calcified cysticerci and increased eosinophil levels in the blood
Scolex, Proglottid
Taenia solium
Cysticercus
Cysticercosis
Taenia saginata is a ___ tapeworm not very important and mainly asymptomatic
Diphyllobothrium latum is the ___ tapeworm and causes nonspecific abdominal syndromes and can also cause ___ since it absorbs ____ and causes a deficiency
^** 2 Intermediate hosts needed which include crustaceans and fish
Hymenolepis nana is a ____ tapeworm and has NO intermediate hosts (aka autoinfection)
Echinococcus causes ___ disease and has its life cycle with ___ and ____ and once humans ingest the eggs (similar to Taenia solium) the eggs hatch in the intestine and disseminate throughout the body (mainly liver and lung)
^** In humans the larvae migrates to the tissues and forms a ____, which can burst and humans are EXTREMELY allergic to the fluid inside the cyst
If a cyst forms in the liver, abdominal pain, palpable liver mass, and biliary obstruction is seen and in the lungs the cyst can cause cough or chest pain and if either of these cysts burst, the allergic reaction can be fatal
Beef
Fish, anemia, Vitamin B12
Dwarf (smallest tapeworm)
Hydatid disease, Dogs and Sheep
Hydatid cyst
Prions (aka TSE = Transmissible spongiform encephalopathies) has long incubation times, no host immune responses, and no inflammatory processes in the brain even though they cause brain damage
Upon microscopy, ___ changes (small, empty, vacuoles of varying size with neural tissue), neuronal loss, amyloid plaques, and accumulation of the prion protein (PrP) is seen
PrP exists in two forms, PrP___ (cellular isoform) and Prp___ (scrapie) that differs in their conformation
^** PrPC has a pos-translational conformational change to PrPSc when only a small amount of PrPSc is present leading to dementia, ataxia, myoclonic jerks, and death
The PrPC can turn into PrPSc via either an inhertied mutation in the PrP gene favoring PrPSc, infection by PrPSc causing PrPC to undergo a conformation change, or sporadic via spontaneous conversion of PrPc to PrPSc
Spongiform
PrP-C and PrP-Sc
There are 4 prion diseases known
1) CJD (Creutzfeldt-Jakob disease)
^** CJD is sub-classified as either sporadic (sCJD), a new variant (vCJD) aka ____ etiology, familial inherited (fCJD), or iatrogenic (iCJD) aka ___ etiology
** Iatrogenic means illness caused by medical examination of treatment
** So realize iCJD and vCJD are infectious, while sCJD is sporadic and fCJD is inherited
2) Kuru disease (aka shivering) has ___ etiology
3) GSS (Gerstmann-Straussler Scheinker disease) has ____ etiology
4) FFI (fatal familial insomnia) has ____ etiology
Mad cow disease (aka Bovine Spongiform Encephalopathy in cattle = BSE) is considered in the ___ prion disease class
Contaminated surgical isntruments, dural and corneal grafts, and administration of cadaveric pituitary hormones is linked to the ___ prion diseases
PrPSc present in lymphoreticular tissue is a defining feature of ___ so a tonsil biopsy with PrPSc is indicative of vCJD
Periodic sharp and slow waves (Aka PSWC) is characteristic for ___ patients
The tau protein is seen in ___ patients and the 14-3-3 is a good marker for ___ patients
1) Infectious, infectious
2) Infectious
3) Inherited
4) Inherited
vCJD
iCJD
vCJD
sCJD (Sharp and Slow = S)
vCJD, sCJD
Staph aureus is resistant to antibiotics since they produce ____ enzymes
KPC (Klebsiella pneumoniae carbapenemase) is a carbapenemase aka a beta-lactamase that confers resistance to the carbapenem class
Outer membrane permeability like the loss of porin in the outer membrane of the gram - bacteria (like in Pseudomonas aeruginosa) can cause antibiotics to not get into the cells and destroy them
Beta-lactamase
The most dangerous agents or diseases that can be weaponized include
1) Anthrax
2) Plague
3) Tularemia
4) Botulism
5) Viral hemorrhagic fevers
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