Parasitology AAB questions and answrs(latest upate)

Human parasite; trophozoite motile, reproducing, feeding stage amebae excreeted as trophozoites cant mature to cyst infective stage Human parasite; cyst nonmotile; nonfeeding stage infective stage for humans transission of cys stage by fecally contam food or water cxcystation occurs in lower intestine, and organisms begin to mult as trophozoites human parasites: identifying cyst round oval shape, non motile, refractile, thick wall, often 1 nucleus human parasite; i dentifying trophozoite irregular shape, motile ( pseudopods) usually 1 nucleus human parasite; ID genus entamoeba true ameba - peripheral chromatin ( visible nuclear mem in both cyst and trophozoite) and chromatoid bodies in cysts only human parasite; ID genus endolimax or Iodamoeba ( other amebae) neither periheral chromatin nor chromatoid bodies human parasite; entamoeba histolytica/entomoeba dispar group contains 2 diff orgs entomboeba histolytica ( true pathogen) entamoeba dispar ( nonpatho) cant ID true E. histo unless trophozoites contain ingested RBC human parasite; Entamoeba coli nonpathogenic human parasite ; Entomoeba polecki swine pathogen that humans acquire, much less common human parasite Entomoeba hartmanni morphology similar to entomoeba dispar but smaller cyst < 10um, trophozoite < 12 um Trophozoites of E. histolytics/ E. dispar/ E. harmani all have -small delicate ( often centric) karyosomal chromatin -fine evenly peripheral chromatin -"clean" cytoplasm devoid of bacteria unless specimen permitted to stand at room temp before examining or staining -progressive motility with abrupt protrusion of hyaline fingerlike pseudopods E. histolytica ( if pathogen) may ___? ingest red cells - dense if still intact; pale if partially digested - E. dispar, E. hartmani do not E. histolytica infec often accompanied by charcot- leyden crystals - disintegration products of eosinophils - pyramidal crystals that stain bright red on trichrome staining E. hemolytica as patho can cause amebiases amebic dysentery ( flask shapped colon ulcers) extraintestinal amebiasis extraintestinal amebiasis caused by E. hemolytica - liver most involved ( amebic hepititis) - brain ( 2ndary amebic encephelitis) - skin lung, etc - incidence -----commmon in tropics and subtropics ( often a pathogen) ----- 5% incidence in US ( carrier state mostly) Both cysts of E. histolytica and E. hartmanni have -small delicate centric karysomal chromatin -fine, even peripheral chromatin -1,2,4 nuclei ( nuc division accompanies cyst maturation) -cigar shaped, round ended chromatoid bodies freq seen Differentiate E. histolytica and E. hartmanni by size histolytica cysts 10-20 um harmani cysts <10um trophozoites of Entamoeba coli and polecki - smudgy, deep staining karysomal chromatin - heavy irreg periph chromatin - " dirty" ( granular) cyto with numerous vacoules, ingested bacteria, yeasts, other parasites - sluggish motility with slow forming blunt granular pseudopods - Cysts of Entamoeba coli and polecki both have large smudgy eccentric karysomal chromatin coarse irreg periph chromatin Entamoeba coli and polecki differentiation E. coli cysts is irreg, lopsides with -chromatoid bodies with 2 pointed ends, rarely seen except in immature cysts - bodies can be round, triangular, oval as well, binucleate cysts are common - mature cyst has 8 nuclei E. poleki has _____ bodies angular chromatoid - inclusion body next to nucleus - 1 nucleus Endolimax nana -trophozoit small 6-8 um with sluggish motility ( blunt hyaline pseudopods) -both trophozoite and cysts: large blotlike karysomal chromatin, usually surrounded hy hyaline area - round to oval cyst with 4 nuclei Iodamoeba butschlii larger, 8-20 um than E. nana, varies in size and shape irregular large karysomal chromatin with hyaline area - central in trophozoite - eccentric in cysts - acromatic granules may be visualized on staining sluggis motility ( blunt hyaline pseudopod) in trophozoite Iodamoeba butschlii nucleus characteristic 1 nucleus in both tropho and cyst Iodamoeba butschlii motility sluggish motility ( blunt hyaline pseudopod) in trophozoite Iodamoeba butschlii conspicuous glycogen vacoule in cyst deep brown circumscribed by iodine in wet prep colorless ( dissolved by alcohol) on trichrome staining Amabae ( free living) inhab the CNS soil and water usually acquired by swimming or diving in stagnant water ( warm). 10ppm chlorine in pools not fatal to naegleria Amabae ( free living) inhab the CNS enter through nasal mucosa, penetrate cribform plate, mult in grey matter of brain Amabae ( free living) inhab the CNS purulent CSF high wbc- PMNs rbc, wbc, ameboid trophozoites failure to find bacteria in prurulent spinal fluid= alert- amebic meningoencephilitis Amabae ( free living) inhab the CNS stain doesnt stain well with usual procedure