Parasitology Flashcards
what parasite organisms are the modified acid fast stain best for identifying?
Cryptosporidium, Cystoisospora, and Cyclospora cayetanensis
what is a cestode? give primary examples
a subclass of helminths, true tapeworm; includes Taenia spp (saginata/beef and solium/pig), Diphyllobothrium latum (fish), Hymenolepsis nana (dwarf), Echinococcus granulosus (dog, hydatid cysts!)
What is a nematode? give primary examples
the roundworm class of helminths: Enterobius vermicularis (pinworm), Trichuris trichuria (whipworm), Ascaris lumbricoides (giant intestinal), Strongyloides stercoralis (threadworm), Necator americanus & Ancylostoma duodenale (hookworms), Trichinella spiralis, and Dracunculus medinensis (guinea)
What are Filariae? Give 4 main pathogenic spp
type of nematode/roundworm that inhabit circulatory and lymphatic system, sometimes muscle and serous cavities or connective tissue
Loa loa, Wuchereria bancrofti, Brugia malayi, & Onchocerca volvulus
What are trematodes/ 5 examples
flukes: Schistosoma spp (mansoni, japonicum, haematobium), Paragonimus westermani, Clonorchis sinensis, Fasciolopsis buski, Fasciola hepatic
Three hemoflagellate extraintestinal protozoa:
Leishmania, Trypanosoma cruzi, and T. brucei
In the protozoan phylum Apicomplexa there is a group of intestinal parasites that infect vertebrates; name the group and 4 main species and major stain used/diffs btw
Coccidia: Cryptosporidium parvum- 4-6um oocysts;
Cyclospora cayetanensis- 8-10 um oocysts; Cystoisospora belli- 25 -30 um ellipsoid oocysts; Toxoplasma gondii- don’t see the cysts, so diagnosed by serology for antibodies. The 3 previous are seen with modified acid fast stain
Name 6 major intestinal protozoan amebae
Entamoeba histolytica/dispar; Entamoeba hartmanni; Entamoeba coli; Endolimax nana; Iodameoba butschlii; Blastocystis hominis
Differentiate between E. histolytica/dispar, E. hartmanni, and Entamoeba coli based on size, nuclei and the peripheral chromatin and karyosome
E. histolytica/dispar (appear same unless ingested RBC meaning histolytica): “medium” cyst and troph, 12-15/ 15-20 um. Fine peripheral chromatin, small central karyosome and no >4 nuclei
E. hartmanni: SMALL, cyst 5-8 um, troph 5-10; fine peripheral chromatin, small central karyosome, never >4 nuclei
E. coli: LARGE at cysts 15-25, trophs 20-25. LARGE eccentric karyosomes, and clumpy uneven peripheral chromatin, up to 8 nuclei
How is Endolimax nana diff from E. hartmanni since both small and similar
E. nana although has 4 nuclei, there is no peripheral chromatin
Give an identifying characteristic of Iodameoba butschlii
Both cysts and troph have large karyosome, and cyst has a large iodine-staining vacuole
what free-living ameoba can cause both granulomatous amebic encephalitis and amebic keratitis in contact wearers?
Acanthamoeba
Name 3 flagellate intestinal protozoa
Giardia lamblia, Chilomastix, and Dientamoeba fragilis
Diff btw Giardia, Chilomastix, and Dientamoeba fragilis
Dientamoeba has no cyst stage, the troph is ROUND AND BINUCLEATE, with fractured central karyosomes and no periph chromatin;
Giardia: cysts oval, 12 x 18 um avg, 4 nuclei, no peripheral chromatin and 2 -4 comma shaped median bodies. Trophs pear-shaped, 2 large nuclei opposite central axostyle, 2 parabasal bodies (old man)
Chilomastix: cysts round, 5-10 um, one nucleus, central karyosome, no periph chrmtn, clear cytostome. Troph- pear shaped, 5-25 x 5-10 um, ONE nucleus, eccentric karyosome, very large cystosome, spiral groove
What is the only pathologic intestinal ciliate in humans and describe briefly
Balantidium coli. Rouond, 43-65 um, has a macronucleus and micronucleus in both cyst and troph stage. Cysts have a double cell wall with cilia in between
Which Plasmodium spp: have enlarged infected RBCs, Shuffner’s dots? How do they differ?
P. vivax and P. ovale. The former has 12 to 24 merozoites/schizont, latter has 8-12 (less anyway). P ovale may also have OVAL infected cells, possible fimbriated, and a more compact mature trophozoite (P. vivax’s is amoeboid)
What Plasmodium spp has more delicate ring-forms, a banana shaped gametocyte, and it is rare to see mature trophozoites or merozoites in PB?
P. falciparum
How long is the replication cycle for P. malariae and thus interval of fever spikes? Describe the mature troph and # merozoites in a schizont
72 hours,a quartan fever; Mature troph can be described as a band & basketm and only 6 to 12 merozoites in a rosette form
What Plasmodium spp have tertian fever spikes and how long is this?
P. vivax, P. ovale, and P. falciparum: q 48 hours
what is the most lethal Plasmodium and which can have a true recurrence?
P. falciparum;
P. vivax and ovale
Which Plasmodium infects older cells and which ALL?
older- malariae; falciparum all; other two infect young cells more often.
Describe the differences in eggs of the 3 main Schistoma spp found in feces or urine
S. mansoni: large lateral spine (Think Manson stabbing sideways)
S. haematobium: large terminal spine (think “peeing down, bc it resides around and enters bladder, causing hematuria)
S. japonicum: a round egg, barely noticeable spine
The egg of this trematode (fluke) is found in feces; Infective mertacercariae is acquired from undercooked crabs/crayfish; Adults form in lungs; Describe the egg
The Paragonimus westermani fluke; Yellow-brown (not as dark as egg of ascaris), thick shelled, oval, avg 90 um, obvious and shouldered operculum;
This egg of the trematode/fluke variety looks similar to Paragonimus but is LARGER (2 spp look same)
Fasciola hepatica/ Fasciolopsis buski. average 120 um
