MIcrobiology: Parasites Flashcards
Bloating, flatulence, foul-smelling stools:
Giardia lamblia
Pear-shaped organism with tumbling motility:
Giardia lamblia
Treatment for Giardia infection:
Metronidazole
Organisms you treat with flagyl (6):
Flagyl = metronidazole GET GAP for metro Giardia Entamoeba Trichomonase Gardnerella Anaerobic bacteria H. Pylori
Two nuclei in the trophozoite form, causes diarrhea in hikers:
Giardia
This protozoal infection causes liver abscesses:
Entamoeba histolytica
Blood diarrhea with RUQ pain:
Entamoeba histolytica
Remember that it causes liver abscess
Describe the colonic abscesses associated with Entamoeba infection
Flask-shaped ulcers with a wide base and narrow mouth
Treatment for Entamoeba infection (2 part):
Metronidazole kills amoebae
Iodoquinol kills the cysts
Is chlorine effective in preventing Cryptosporidium infection?
No.
Filtration only.
Cysts seen on acid-fast stain:
Cryptosporidium
In AIDS patients:
Cryptococcus: Diarrhea or meningitis?
Cryptosporidium: Diarrhea or meningitis?
Cryptosporidium -> diarrhea
Cryptococcus -> meningitis
Treatment for Cryptosporidium?
Trick question, there isn’t one.
Prevention is the name of the game.
How do you diagnose Entamoeba infection (3):
Serology OR
Trophozoites containing RBCs in the blood OR
Multi-nucleated cysts in the stool
Trophozoites containing RBCs:
Entamoeba histolytica
Brain abscesses in HIV, ring-enhancing lesions:
Toxoplasma gondii
Classic triad for congenital toxo:
Chorioretinitis
Hydrocephalus
Intracranial calcifications
Treatment for Toxoplasmosis (2):
Sulfadiazine + pyrimethamine
This protozoan causes a rapidly fatal meningoencephalitis:
Where do you get it?
How is it diagnosed?
Naegleria fowleri
From freshwater lakes, up through cribiform plate
Spinal fluid has amoebae
Organism causing African sleeping sickness:
Trypanosoma brucei, gambiense, or rhodesiense
Treatment for African sleeping sickness:
“SUR is nice to take MELAtonin for sleep”
Suramin (for blood-borne disease)
Melarsoprol for CNS infection
Diagnosis of Toxoplasma (2):
Serology
Biopsy
Diagnosis of Trypanosoma infection:
Blood smear
This malaria species has a 48-hr fever cycle.
Malaria species with a 72-hr cycle?
Plasmodium vivax / ovale = 48hr
Plasmodium malariae = 72 hr cycle
This malarial form has no dormant liver form, whereas these two do:
P. falciparum = no dormant form.
P. malariae and vivax/ovale = have a dormant liver form
Banana-shaped gametocyte:
Plasmodium falciparum
RBC filled with merozoites:
Malaria
What is a hypnozoite?
How do you treat it?
Hypnozoite = resting liver form of malaria seen in vivax/ovale and malariae forms.
Tx is with primaquine
The ring form of this parasite can be confused with malaria, why?
How do you tell the two apart?
Babesia’s ring form looks like the banana-shaped gametocyte of P. falciparum.
Babesia does not have hemazoin pigment deposits.
Maltese cross on blood smear:
Babesia
Treatment for babesiosis:
Atovaquone + azithromycin
Chagas’ disease, three common findings:
Dilated cardiomyopathy
Megacolon
Magaesophagus (secondary achalasia)
Treatment for Chagas:
Nifurtimox
Macrophages containing amastigotes:
What is an amastigote?
Leishmania donovani
Amastigote = non-flagellated form of the organism
Ulcerating papules, transmitted by the sandfly:
Leishmania donovani
Spiking fevers, hepatosplenomegaly, pancytopenia:
Leishmania
Treatment for leishmaniasis:
Cutaneous = sodium stibogluconate Systemic = liposomal amphotericin B
Pinworm:
Enterobius vermicularis
Giant roundworm:
Ascaris lumbricoides
Hookworm:
Ancylostoma, Necator
Most common helminth infection in the US:
In the world:
US = Enterobius = pinworm World = Ascaris = giant roundworm
Treatment for Strongyloides infection:
Ivermectin, albendazole
These worms infect by penetrating skin:
SANd Strongyloides Ancylostoma Necator d
These worms are transmitted via fecal-oral route:
EAT
Enterobius
Ascaris
Trichinella
River blindness:
How is it transmitted?
Two features:
Onchocera
Female blackfly bite
Tx = ivermectin
Worm in conjunctiva:
Loa loa
Causes lymphatic filariasis:
Wuchereria
Huge hydrocele, transmitted by a female mosquito, how do you treat it?
This is elephantiasis caused by Wucheria, treat with diethylcarbamazine
Myositis and periorbital edema after eating undercooked bear:
Trichinella
Lives in muscles, dx by biopsy
From undercooked wild game or pork
New onset of neurologic symptoms in a young immigrant:
Taenia solium, think neurocysticercosis
Treatment for neurocysticercosis:
Praziquantel +
Bendazoles
How is Taenia solium transmitted to people?
Ingestion of undercooked pork (larvae)
Ingestion of eggs (fecal-oral)
Came from dog feces, hyadatid cysts in liver:
Echinococcus
Leak of liver cyst contents caused anaphylaxis:
Echinococcus
Ate a raw freshwater fish and got vitamin B12 deficiency:
Diphyllobothrium
Blood fluke:
Schistosoma
Snail host:
Schistosoma
Undercooked fish, causes pigmented gallstones:
Clonorchis
Brain cysts, seizures:
Taenia (tapeworm)
Liver cysts:
Echinococcus (tapeworm)
Vitamin B12 deficiency:
Diphyllobothrium (tapeworm)
Biliary tract disease and cholangiocarcinoma:
Clonorchis (fluke)
Hemoptysis, crab meat:
Paragonimus (the “lung” fluke)
Portal HTN:
Schistosoma mansoni (blood fluke)
Hematuria and bladder cancer:
Schistosoma haematobium (a blood fluke)
Microcytic anemia:
Ancylostoma &
Necator, both roundworms
Both suck blood from intestinal walls
Perianal pruritis:
Enterobius
What happens if you drink alcohol while on flagyl?
Disulfarim-like reaction, feel awful
Anaerobic infections below the diaphragm you treat with:
Above the diaphragm you treat with:
Below = metronidazole Above = clindamycin
