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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
  • Diagnosis
    • Amoebas in spinal fluid [B]
  • Treatment
    • Amphotericin B has been effective for a few survivors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
  • 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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
  • Transmission
    • Reduviid bug (“kissing bug”) feces, deposited in a painless bite (much like a kiss)
  • Diagnosis
    • Blood smear [A]
  • Treatment
    • Benznidazole or nifurtimox
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Onchocerca volvulus

  • Type of organism
  • Transmission
  • Disease
  • Treatment
A
  • Type of organism
    • Tissue nematode (roundworm)
  • Transmission
    • Female blackfly bite
  • Disease
    • Hyperpigmented skin and river blindness
      • Black flies, black skin nodules, “black sight”
    • Allergic reaction to microfilaria possible
  • Treatment
    • Ivermectin (ivermectin for river** blindness**)
17
Q

Loa loa

  • Type of organism
  • Transmission
  • Disease
  • Treatment
A
  • Type of organism
    • Tissue nematode (roundworm)
  • Transmission
    • Deer fly, horse fly, mango fly
  • Disease
    • Swelling in skin, worm in conjunctiva
  • Treatment
    • Diethylcarbamazine
18
Q

Wuchereria bancrofti

  • Type of organism
  • Transmission
  • Disease
  • Treatment
A
  • Type of organism
    • Tissue nematode (roundworm)
  • Transmission
    • Female mosquito
  • Disease
    • Blocks lymphatic vessels: elephantiasis
    • Takes 9 mo–1 yr after bite to become symptomatic
  • Treatment
    • Diethylcarbamazine
19
Q

Toxocara canis

  • Type of organism
  • Transmission
  • Disease
  • Treatment
A
  • Type of organism
    • Tissue nematode (roundworm)
  • Transmission
    • Fecal-oral
  • Disease
    • Visceral larva migrans
  • Treatment
    • Albendazole or mebendazole
20
Q

Nematode routes of infection

  • Ingested
  • Cutaneous
  • Bites
A
  • Ingested
    • Enterobius, Ascaris, Toxocara
    • You’ll get sick if you EAT these.
  • Cutaneous
    • Strongyloides, Ancylostoma, Necator
    • These get into your feet from the SANd.
  • Bites
    • Loa loa, Onchocerca volvulus, Wuchereria bancrofti
    • Lay LOW to avoid getting bitten.
21
Q

Taenia solium

  • Type of organism
  • Transmission
  • Disease
  • Treatment
A
  • Type of organism
    • Cestode (tapeworm)
  • Transmission
    • (1) Ingestion of larvae encysted in undercooked pork
    • (2) Ingestion of eggs
  • Disease
    • (1) Intestinal infection
    • (2) Cysticercosis, neurocysticercosis
  • Treatment
    • (1) Praziquantel
    • (2) Praziquantel; albendazole for neurocysticercosis
22
Q

Diphyllobothrium latum

  • Type of organism
  • Transmission
  • Disease
  • Treatment
A
  • Type of organism
    • Cestode (tapeworm)
  • Transmission
    • Ingestion of larvae from raw freshwater fish
  • Disease
    • Vitamin B12 deficiency (tapeworm competes for B12 in intestine) Ž–> anemia
  • Treatment
    • Praziquantel
23
Q

Echinococcus granulosus

  • Type of organism
  • Transmission
  • Disease
  • Treatment
A
  • Type of organism
    • Cestode (tapeworm)
  • Transmission
    • Ingestion of eggs from dog feces
  • Disease
    • Hydatid cysts in liver, causing anaphylaxis if antigens released
    • Surgeons preinject with ethanol to kill cysts before removal
  • Treatment
    • Albendazole
24
Q

Schistosoma

  • Type of organism
  • Transmission
  • Disease
  • Treatment
A
  • Type of organism
    • Trematode (fluke)
  • Transmission
    • Snails are host
    • Cercariae penetrate skin of humans
  • Disease
    • Liver and spleen granulomas, fibrosis, and inflammation
    • Chronic infection with S. haematobium can lead to squamous cell carcinoma of the bladder (painless hematuria)
  • Treatment
    • Praziquantel
25
Q

Clonorchis sinensis

  • Type of organism
  • Transmission
  • Disease
  • Treatment
A
  • Type of organism
    • Trematode (fluke)
  • Transmission
    • Undercooked fish
  • Disease
    • Biliary tract inflammation –>Ž pigmented gallstones
    • Associated with cholangiocarcinoma
  • Treatment
    • Praziquantel
26
Q

Parasite hints

  • Biliary tract disease, cholangiocarcinoma
  • Brain cysts, seizures
  • Hematuria, bladder cancer
  • Liver (hydatid) cysts
  • Microcytic anemia
  • Perianal pruritus
  • Portal hypertension
  • Vitamin B12 deficiency
A
  • Biliary tract disease, cholangiocarcinoma
    • Clonorchis sinensis
  • Brain cysts, seizures
    • Taenia solium (cysticercosis)
  • Hematuria, bladder cancer
    • Schistosoma haematobium
  • Liver (hydatid) cysts
    • Echinococcus granulosus
  • Microcytic anemia
    • Ancylostoma, Necator
  • Perianal pruritus
    • Enterobius
  • Portal hypertension
    • Schistosoma mansoni, Schistosoma japonicum
  • Vitamin B12 deficiency
    • Diphyllobothrium latum