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IntrotoParasitology
lecture 30 lee
Question | Answer |
---|---|
2 forms of protozoa | cyst and trophozoite |
trophozoite | actively feeding organisms in the host niche |
protozal cysts | metabolically inactive form that can survive under very unfavorable conditions, resistant to chlorination and drying |
2 organisms that DO NOT HAVE cyst form | Dientamoeba fragilis and Trichomonas vaginalis |
schizogony in protozoa | binary fission or asexual reproduction in humans |
sporogony in protozoa | sexual reproduction, usually restricted to within insect vectors |
how to dx intestinal protozoa | stool O&P - using wet mount with saline or iodine or trichome staining |
protozoa that stain with acid-fast agents | Cryptosporidium, Isospora, Cyclospora (sporozoans) |
most common protozoal infection in the US | Giardia lamblia |
early vs late Trypanosoma cruzi infection | Chagas dz: early - parisitemia with nonfocal fever syndrome; late - aka 1-2 decades later, cardiomyopathy and arrhythmias, megacolon or esophagus |
characteristics of Plasmodium on blood smear | look like headphones (just as Babesia does) within the RBCs, banana-shaped gametocyte |
the only helminth that multiplies within the human host | Strongyloides stercoralis, means larvae can be found in stool!! (not eggs) |
characteristic systemic changes that reflect parasite responses | eosinophilia (characteristic of migrating worms), edema, arthralgia |
pinworms (Enterobius vermicularis) | infect young children and cause nocturnal anal pruritis, eggs will stick to scotch tape |
Loeffler's syndrome | cough, dyspnea, hemoptysis, eosinophilic pneumonitis can occur during the lung phase of larval migration; you cough up sputum and swallow it then the roundworms get to GI tract |
most common helminth infection in humans | roundworks (Ascaris lumbricoides) |
how hookworms infect | larvae in soil penetrate skin in foot perhaps, attach to intestine and eggs are in stool |
Diphyllobothrium latum | fresh water FISH (sushi) and perNISHous anemia |
cysticercosis | humans eat eggs of Taenia solium, common cause of sz in endemic areas especially in young adults |
cause of swimmer's itch | blood flukes or Schistosomes that invade humans accidentally; they live in fresh water. remember - worse on repeat exposure |
forms Maltese crosses/tetrads, causes hemolytic anemia and is endemic to Martha's Vineyard or the East Coast | Babesi microti |