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77 Cards in this Set
- Front
- Back
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As a general rule, do helminths multiply within the host? Is there an exception to this rule?
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Generally, NO!
The exception is Strongyloides |
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What determines the severity of an infection by helminths?
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The amount of helminths ingested
The hypersensitivity reaction to the helminth infection |
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What are the modes by which helminths can enter into the body?
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Ingestion (eggs/cysts); inestinal
Arthropod bites; (larvae) Penetration of intact skin/musous membranes (larvae) |
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What is a serious complcation caused by a hookworm infection?
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Anemia
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What is the treatment of hookworms?
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Antihistmains
Antihelminthic drugs |
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What is a common finding in helminth infections?
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EOSINOPHILA!!! due to type I hypersensitivity
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What are the different kinds of helminths?
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Nematodes (roundworms)
platyhelminthes (flatworms) |
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What are the different kinds of flatworms?
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Trematodes (flukes)
Cestodes (tapeworms) |
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What are three pathogen causing roundworms/nematodes?
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Strongylides
Trichinosis Filaria |
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What are roundworms that cause invasive disease?
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Trichinosis
Filaria |
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What is a roundworm that causes intestinal disease?
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Strongyloides
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What is a fluke that causes invasive disease?
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Schistosomiasis
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What counterintuitive systemic problem can an intestinal nematode cause?
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Loeffler's pneunomia
The larvae go through the respiratory tree en route to the intestine. |
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What kind of intestinal nematode can cause obstruction?
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Ascaris
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What is unique about the strongyloides life cycle?
How does this happen? |
Autoinfection
If it stays in the intestine large enough, it can develop enough to be able to reburrow through the skin of the anus. |
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What is the typical lifecycle of an intestinal nematode?
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1. Entry of the nematode through the skin (larva)/ingestion (eggs)
2. Entry of the larvae into the the bloodstream 3. Migration to the lungs 4. Go up to the epiglottis; back down to the intestine. 5. Release of eggs into the environment |
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What are the initial symptoms of trichinosis?
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Severe myalgia (head/neck), weakness
Muscle tenderness Increased CPK Fever Facial, periorbical edema |
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How long does it take for the initial symptoms of trichinosis to appear?
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2-4 weeks?
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What are the later, more serious symptoms of trichinosis?
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Neurologic
Cardiac 4-8 weeks post-exposure |
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What helminth causes trichinosis? How does one contract this?
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Trichinella spiralis
By eating encysed larvae. Burrow into intestine --> Mature --> Reemerge as adults --> Larvae circulate in bloodstream --> Larvae enter into tissues; pathology. |
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What is the disease that Trichinela spiralis causes? What are the symptoms?
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Trichanosis
Abdominal discomfort, Cramping, Diarrhea, Facial swelling around the eyes, Fever, Muscle pain (especially muscle pain with breathing, chewing, or using large muscles), Muscle weakness |
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What is the life cycle of Trichinella?
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Passed back and forth between carnivores: rats and pigs
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Where is the target of Trichinella spiralis? What does the helminth do there?
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Muscle; encysts
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What kind of organism will one never contract Trichinella spiralis from?
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Herbivores
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What is the treatment of trichinosis?
Where is this treatment effective? |
Antihelminthic drug
Steroids for inflammatory reactions Can only get rid of the intestinal bugs; the cysts you need to wait for them to die |
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What is the vector of lymph-dwelling filaria?
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Mosquitos
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What is the vector of skin-dwelling filaria?
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Biting flies
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Where do lymph-dwelling filaria larvae localize in the body?
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Bloodstream, where they're picked up by mosquitos
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Where do skin-dwelling filaria larvae localize to in the body?
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Dermis
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What disease is caused by skin-dwelling filaria?
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Onchocerciasis/River blindness.
Scarring of the cornea by the worms |
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What disease does lymph-dwelling microphilaria cause?
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Elephantitis: unilateral edema due to blockage of lymphatic drainage
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What are the visible symptoms of an infection by O. volvulus?
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Nodules in the skin
Depigmentation |
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What is a sign of a Loa Loa infection?
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Microfilaria crossing the conjuctiva
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What is the geographic locale of Loa Loa?
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Togo - Nigeria - Cameroon -Gabon
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What type of a nonhuman parasite can cause a calcified lung cyst?
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Diriofilaria - a dog heartworm.
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What is the role of endosymbionts in filiaria infections?
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Required for fecundity/viability
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What are the implications of endosymbionts in filaria treatment?
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Get rid of the endosymbionts and the filaria will die.
Tx. with tetracycline. |
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What is the geographic locale of schistosomiasis?
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Afria
East Asia Eastern Brazil |
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What is the animal reservoir for Schistosomiasis?
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SNAILS!
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Where can one contract Schistosomiasis?
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Inside polluted water that has snails inside of it.
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What is the life cycle of Schistosomiasis?
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1. Defecation into water
2. Larva released from egg; infect snail 3. Growth in snail, release into water 4. Penetration of skin by larva 5. Travelling through circulation to lungs, develop 6. Travel to intestine/bladder complex 7. MATE FO LIFE!/egg production 8. Spread to liver, colon, urinary tract |
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Where are common targets at the end of a Schistosomiasis infection?
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Colon
Liver Urinary tract |
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What are the three types of Schistosomiasis?
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S. mansoni
S. haemotobium S. japonicum |
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What is unique about the morphology of S. mansoni?
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Little spike on the side...kind of like a comic book bubble!
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What is the location in the body that S. mansoni likes?
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The inferior mesenteric venules
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Where is main ultimate target of S. mansoni?
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Liver
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What is the location of S. haematobium in the body?
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Bladder plexus
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What is the schistosomiasis speces that localizes to the intestine?
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Mansoni
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What is the schistosomiasis species that localizes to the urinary tract?
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Haematobium
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What is the ultimate destination of S. haematobium?
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Lungs
NOT THE LIVER |
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What is the location in the body that S. japonicum likes?
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Intestine; superior mesentaric venules
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What is a serious hepatic complication of an infection by schistosomiasis.
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Pipestem fibrosis due to severe deposition of schistosomiasis throughout the biliary tract
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What are the symptoms of "pipestem" fibrosis
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Ascites
Enlarged stomach NORMAL LIVER FUNCTION!!!! Severe hemerroids |
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What is the most likely cause of death from pipestem fibrosis?
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Hemorrhage
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What is the unique kind of immunity to Schistosomiasis?
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Concomitant immunity
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What is the mechanism of concomitant immunity in this parasite? Why does only this form of immunity occur?
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Schistosomiasis
Antibodies, etc., to the form of the parasite that enters into the body NO IMMUNITY TO THE ADULT WORMS; THEY COAT THEMSELVES WITH HOST PROTEINS |
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What are the mechanisms of immune evasion by Schistosomiasis?
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Camouflage by host proteins
Minimal surface expression of surface antigens This is the reason that there's only concomittant immunity to schistosomiasis infections. |
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Where are areas in the body where Schistosomiasis is able to localize?
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Intestine
Liver/Spleen Urinary tract |
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What are symptoms of an intestinal Schistosomiasis infection?
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Granulomas --> Polyps
Protein loss Malabsorption Strictures |
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What are symptoms of a hepatosplenic Schistosomiasis infection?
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Portal hypertension causing:
Ascites Varices Splenomegaly ALL WITH NORMAL HEPATIC FUNCTION! |
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What are the symtpoms of a urinary Schistosomiasis infection?
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Hematuria
Chronic infection Obstruction Kidney failure Squamous cell carinoma of the bladder |
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What is the treatment for Schistosomiasis?
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Praziquantel: increasing Ca permeability
ONE DAY OF TREATMENT! |
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What are important mechanism of control for Schistosomiasis?
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Reduce the carries: mass treatment
WAGE A WAR ON SNAILS! Prevent water contamination (latrines/toilets) Prevent human exposure (water systems) |
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What makes a person a definitive host of taperworms?
How does one become this? |
If you've got an adult worm
Ingestion of tissue cysts from undercooked meat |
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What makes someone an intermediate host of pork tapeworms?
How does one become this? What symptoms are shown? |
Harboring tissue cysts
Ingestion of eggs from feces Cysts all over the body: liver, brain, etc. |
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What is the meat/animal associated with tapeworm infection?
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Pork/Pigs
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What parasite causes cysticercosis?
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Tenia solia
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What disease can tenia solia cause?
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Cysticercosis
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What organ is a target in Cysticercosis?
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The brian
Cysts on the brain CT |
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What is the difference between Cysticerci and Hydatid cysts?
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Cystercerci are from pork tapeworms. Individual bugs per cyst.
Hydatid cysts are from echinococcus. Many, many tapeworms produced by the membrane of the big cyst. |
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What are the common animals associated with Echinococcosis?
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Sheep and Sheepdogs
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What is the mechanism of spread of Echinococcosis?
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Contact with dogs with tapeworm eggs on their fur. We then have cysts.
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What are the consderations for treatment of Echinococcosis cysts?
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If you puncture the cyst, you could cause a systemic inflammatory response.
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What nonsurgical treatment is used for the treatment of cysticercosis and Echinococcosis?
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Antihelminthic therapy
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What is the definitive host for Echinococcosis?
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Dogs
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What is the target organ in a cystercircosis infection? What organism causes this? What form of the organism would you have to ingest to show the pathology?
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The brain.
Cysts. Tenia solia You'd have to eat the eggs. These would encyst and travel up to the brain; you're an intermediate host. If you were to eat the CYSTS you'd have worms in your stomach; you're a definite host. |
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What are the considerations in treating an infection by Echinococcus?
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Hydatid cysts can burst, spreading parasites all over the body! Bad news bears!!!
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