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66 Cards in this Set
- Front
- Back
What is the most common protozoal infection in man?
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Toxoplasma gondii
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What is the natural host of Toxo?
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Mice
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How do cats acquire Toxo?
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By eating raw mouse meat
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How do humans acquire Toxo?
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1. By eating raw meat infected with it
2. By playing with cats |
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What is the form of Toxo that humans ingest? What happens after it is ingested?
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-Ingest cysts/pseudocysts
-Tachyzoites mature and go to liver, remain for life.. |
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Can humans pass on Toxo?
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No; they are an incidental host, dead end.
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Who is primarily concerning if they get a primary Toxo infection?
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Pregnant females
-Most alarming if acquired in 1st trimester |
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When does transmission to the fetus occur most often in pregnancy?
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3rd trimester
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When does most morbidity occur due to Toxo transmission in pregnancy?
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In the 1st trimester
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What does Toxo infection do to most individuals?
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Nothing
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What types of symptoms when Toxo does cause symptoms most often?
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Mono-like symptoms
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What is the most common symptom of congenital Toxo infection?
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Chorioretinitis
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What symptoms result from Toxo getting reactivated due to a low CD4 count in AIDS?
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CNS infection
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What is the main way to diagnose Toxo?
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Based on serology
-If IgM is high, recent inf. -If IgG is present, prior |
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What do you have to do to test for and monitor Toxo infections in AIDs patients?
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Antigen detection - their serum antibody is too low.
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When does Toxo require treatment?
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-Congenital
-Ocular -Persistent disease -AIDS |
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What drugs are used to treat Toxo?
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Bactrim and Clindamycin
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What other disease is concerning in AIDs?
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Pneumocystis carinii
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What is the stain for Pneumo carinii?
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Silver stain
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What 2 things show up on a sputum silver stain for PCP?
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-Foamy material
-Cyst-like organisms |
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What are the only people that get Pneumocystis infections?
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AIDS and immunocompromised
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What type of infection does PCP cause?
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Atypical lung infection
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What are the 3 ways to diagnose PCP?
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-Sputum (only in AIDS)
-Bronchoscopy -Open lung biopsy |
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What is the treatment for PCP?
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-Bactrim
-Pentamidine -Dapsone |
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What is common in HIV patients with PCP?
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Relapse - so give prophylaxis for life
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Do most AIDS patients that get PCP die?
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No not anymore
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What is the milwaukee protozoan of choice?
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Cryptosporidium
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How is C. parvum transmitted?
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Fecal-oral
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What type of disease does C. parvum cause
-in normals -in immunocompromised |
Normals: Self-limiting diarrhea
HIV/AIDs: Chronic diarrhea |
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How is C. parvum diagnosed?
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With a stool AF stain
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What is the treatment for C. parvum?
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Maintain hydration
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What is the Malaria that causes death?
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Plasmodium falciparum
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What transmits P. falciparum?
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The female anopheles mosquito
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What form infects man?
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Sporozoites
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What happens immediately after the mosquito injects sporozoites into the blood?
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They go to the liver and hide for a while, then re-emerge as merozoites and trophs.
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What form infects red cells?
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Merozoites and Trophozoites
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What happens in RBCs?
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Proliferation and Bursting to release many new merozoites
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What are Gametocytes?
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The sexual form that mature from merozoites and can get re-picked up by mosquitoes.
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Where does the sexual reproduction of Plasmodium species occur?
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Only in mosquitoes - so they have to acquire a male and a female to do it.
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How does P. falciparum kill?
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By causing cerebral malaria
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How does P. falciparum get into the CNS to cause damage?
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It causes RBCs to acquire protrusions that allow the RBCs to adhere to EC's on blood vessels.
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What is the result of RBCs binding to ECs on blood vessels?
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They cause microembolisms within the capillaries of the brain, resulting in infarcts.
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Why is it hard to treat P. falciparum?
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Because it has developed a lot of Chloroquine resistance
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What kind of malaria relapses?
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Only the milder forms - P. vivax and ovale
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What kind of malaria is drug resistant?
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Only P. falciparum
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What are the 4 big manifestations of Malaria?
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-Cyclical fevers (endemic)
-Anemia (endemic) -Cerebral malaria -Acute renal failure |
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Why do we only see cyclical fevers and anemia in infected folks in endemic areas?
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Because in US citizens malaria will cause death long before those more chronic symptoms can develop
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What are the 2 ways to diagnose Malaria?
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-Thick smear
-Thin smear |
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What is a Thick smear done for?
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-Identifying presence
-Differentiating species -ONly by an experienced tech |
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What is a thin smear done for?
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Visualization of finer forms to differentiate species and stages - in Mod to severe cases
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What type of infection is a thick smear sufficient for?
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Light infections
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What are the 2 primary patients that M. falciparum causes disease in?
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-Children
-Pregnant females |
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What are the 3 drugs used for prophylaxis for malaria?
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-Chloroquine
-Mefloquine -Doxycycline |
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Where can Chloroquine be used?
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Central America
North africa Middle East |
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What is used in most areas?
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Mefloquine - but it has toxic side effects
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What is used for people who can't take Mefloquine?
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Doxycycline
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What morphology is unique to P. falciparum?
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Signet rings
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What morphology is seen in the relapsing forms of malaria?
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Schuffner's dots
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What are the only 3 places you can give chloroquine?
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-Central america
-North africa -Middle east |
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To whom is prophylaxis for malaria given?
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-Travelers
-Soldiers |
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What does malaria prophylaxis consist of?
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-Repellants
-Nets -Sprays -Water management |
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Where is the fatality rate of malaria higher? Why?
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In the US because docs are stupid
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What type of parasite is malaria again?
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A protozoan
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What is the infectious form?
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Sporozoites
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What form infects RBCs?
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Merozoites
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Where do the merozoites come from?
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The liver
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