Microbiology - Parasitology Flashcards
1
Q
Giardia lamblia
- Type of organism
- Type of infection
- Disease
- Transmission
- Diagnosis
- Treatment
A
- Type of organism
- Protozoa
- Type of infection
- GI infection
- Disease
- Giardiasis: bloating, flatulence, foul-smelling, fatty diarrhea (often seen in campers/hikers)
- Think fat-rich Ghirardelli chocolates for fatty stools of Giardia
- Transmission
- Cysts in water
- Diagnosis
- Trophozoites [A] or cysts [B] in stool
- Treatment
- Metronidazole
2
Q
Entamoeba histolytica
- Type of organism
- Type of infection
- Disease
- Transmission
- Diagnosis
- Treatment
A
- Type of organism
- Protozoa
- Type of infection
- GI infection
- Disease
- Amebiasis: bloody diarrhea (dysentery), liver abscess (“anchovy paste” exudate), RUQ pain (histology shows flask-shaped ulcer if submucosal abscess of colon ruptures)
- Transmission
- Cysts in water
- Diagnosis
- Serology and/or trophozoites (with RBCs in the cytoplasm) [C] or cysts (with up to 4 nuclei) [D] in stool
- Treatment
- Metronidazole
- Iodoquinol for asymptomatic cyst passers
3
Q
Cryptosporidium
- Type of organism
- Type of infection
- Disease
- Transmission
- Diagnosis
- Treatment
A
- Type of organism
- Protozoa
- Type of infection
- GI infection
- Disease
- Severe diarrhea in AIDS
- Mild disease (watery diarrhea) in nonimmunocompromised
- Transmission
- Oocysts in water
- Diagnosis
- Oocysts on acid-fast stain [E]
- Treatment
- Prevention (by filtering city water supplies)
- Nitazoxanide in immunocompetent hosts
4
Q
Toxoplasma gondii
- Type of organism
- Type of infection
- Disease
- Transmission
- Diagnosis
- Treatment
A
- Type of organism
- Protozoa
- Type of infection
- CNS infection
- Disease
- Brain abscess in HIV (seen as ring-enhancing brain lesions on CT/MRI)
- Congenital toxoplasmosis = “classic triad” of chorioretinitis, hydrocephalus, and intracranial calcifications
- Transmission
- Cysts in meat or oocysts in cat feces
- Crosses placenta (pregnant women should avoid cats)
- Diagnosis
- Serology, biopsy (tachyzoite) [A]
- Treatment
- Sulfadiazine + pyrimethamine
5
Q
Naegleria fowleri
- Type of organism
- Type of infection
- Disease
- Transmission
- Diagnosis
- Treatment
A
- Type of organism
- Protozoa
- Type of infection
- CNS infection
- Disease
- Rapidly fatal meningoencephalitis
- Transmission
- Swimming in freshwater lakes
- Think Nalgene bottle filled with fresh water containing Naegleria
- Enters via cribriform plate
- Swimming in freshwater lakes
- Diagnosis
- Amoebas in spinal fluid [B]
- Treatment
- Amphotericin B has been effective for a few survivors
6
Q
Trypanosoma brucei
- Type of organism
- Type of infection
- Disease
- Transmission
- Diagnosis
- Treatment
A
- Type of organism
- Protozoa
- Type of infection
- CNS infection
- Disease
- African sleeping sickness: enlarged lymph nodes, recurring fever (due to antigenic variation), somnolence, coma
- Two subspecies: Trypanosoma brucei rhodesiense, Trypanosoma brucei gambiense
- Transmission
- Tsetse fly, a painful bite
- Diagnosis
- Blood smear [C]
- Treatment
- Suramin for bloodborne disease or melarsoprol for CNS penetration
- “It sure is nice to go to sleep”; melatonin helps with sleep
7
Q
Plasmodium: P. vivax/ovale, P. falciparum, P. malariae
- Type of organism
- Type of infection
- Disease
- Transmission
- Diagnosis
- Treatment
A
- Type of organism
- Protozoa
- Type of infection
- Hematologic infection
- Disease
- Malaria: fever, headache, anemia, splenomegaly
- P. vivax/ovale
- 48-hr cycle (tertian; includes fever on first day and third day, thus fevers are actually 48 hr apart)
- Dormant form (hypnozoite) in liver
- P. falciparum
- Severe
- Irregular fever patterns
- Parasitized RBCs occlude capillaries in brain (cerebral malaria), kidneys, lungs
- P. malariae
- 72-hr cycle (quartan)
- Transmission
- Mosquito (Anopheles)
- Diagnosis
- Blood smear, trophozoite ring form within RBC [A], schizont containing merozoites [B]
- Treatment
- Begin with chloroquine, which blocks Plasmodium heme polymerase
- If resistant, use mefloquine or atovaquone/ proguanil
- If life-threatening, use intravenous quinidine (test for G6PD deficiency)
- Vivax/ovale—add primaquine for hypnozoite (test for G6PD deficiency)
- Begin with chloroquine, which blocks Plasmodium heme polymerase
8
Q
Babesia
- Type of organism
- Type of infection
- Disease
- Transmission
- Diagnosis
- Treatment
A
- Type of organism
- Protozoa
- Type of infection
- Hematologic infection
- Disease
- Babesiosis
- Fever and hemolytic anemia
- Predominantly in northeastern United States
- Asplenia increases risk of severe disease
- Babesiosis
- Transmission
- Ixodes tick (same as Borrelia burgdorferi of Lyme disease; may often coinfect humans)
- Diagnosis
- Blood smear, ring form [C1], “Maltese cross” [C2]; PCR
- Treatment
- Atovaquone + azithromycin
9
Q
Trypanosoma cruzi
- Type of organism
- Type of infection
- Disease
- Transmission
- Diagnosis
- Treatment
A
- Type of organism
- Protozoa
- Type of infection
- Visceral infection
- Disease
- Chagas disease
- Dilated cardiomyopathy, megacolon, megaesophagus
- Predominantly in South America
- Chagas disease
- Transmission
- Reduviid bug (“kissing bug”) feces, deposited in a painless bite (much like a kiss)
- Diagnosis
- Blood smear [A]
- Treatment
- Benznidazole or nifurtimox
10
Q
Leishmania donovani
- Type of organism
- Type of infection
- Disease
- Transmission
- Diagnosis
- Treatment
A
- Type of organism
- Protozoa
- Type of infection
- Visceral infection
- Disease
- Visceral leishmaniasis (kala-azar): spiking fevers, hepatosplenomegaly, pancytopenia
- Transmission
- Sandfly
- Diagnosis
- Macrophages containing amastigotes [B]
- Treatment
- Amphotericin B, sodium stibogluconate
11
Q
Trichomonas vaginalis
- Type of organism
- Type of infection
- Disease
- Transmission
- Diagnosis
- Treatment
A
- Type of organism
- Protozoa
- Type of infection
- STD
- Disease
- Vaginitis: foul-smelling, greenish discharge; itching and burning
- Do not confuse with Gardnerella vaginalis, a gram-variable bacterium associated with bacterial vaginosis
- Transmission
- Sexual (cannot exist outside human because it cannot form cysts)
- Diagnosis
- Trophozoites (motile) [C] on wet mount
- “Strawberry cervix”
- Treatment
- Metronidazole for patient and partner (prophylaxis)
12
Q
Enterobius vermicularis (pinworm)
- Type of organism
- Transmission
- Disease
- Treatment
A
- Type of organism
- Intestinal nematode (roundworm)
- Transmission
- Fecal-oral
- Disease
- Intestinal infection causing anal pruritus (diagnosed via the Scotch Tape test)
- Treatment
- Bendazoles or pyrantel pamoate (because worms are bendy)
13
Q
Ascaris lumbricoides (giant roundworm)
- Type of organism
- Transmission
- Disease
- Treatment
A
- Type of organism
- Intestinal nematode (roundworm)
- Transmission
- Fecal-oral
- Eggs visible in feces under microscope
- Disease
- Intestinal infection
- Treatment
- Bendazoles or pyrantel pamoate
14
Q
Strongyloides stercoralis
- Type of organism
- Transmission
- Disease
- Treatment
A
- Type of organism
- Intestinal nematode (roundworm)
- Transmission
- Larvae in soil penetrate the skin
- Disease
- Intestinal infection causing vomiting, diarrhea, epigastric pain (may be peptic ulcerlike)
- Treatment
- Ivermectin or albendazole
15
Q
Ancylostoma duodenale, Necator americanus (hookworms)
- Type of organism
- Transmission
- Disease
- Treatment
A
- Type of organism
- Intestinal nematode (roundworm)
- Transmission
- Larvae penetrate skin
- Disease
- Intestinal infection causing anemia by sucking blood from intestinal walls
- Treatment
- Bendazoles or pyrantel pamoate