Dr. Libman -- Parasitology 1: Protozoa Flashcards
5 protozoa that affect the intestine
- Entamoeba histolytica
- Giardia
- Isospora
- Cryptosporidium
- Cyclospora
5 protozoa that have a systemic effect
- Malaria
- Babesia
- Toxoplasma
- Leishmania
- Trypanosoma
2 divisions of parasites
Unicellular (protozoa)
Multicellular (helminthes)
3 types of helminthes
- Nematodes
- Cestodes
- Trematodes
4 nematodes that affect the intestine
- Strongyloides
- Ascaris
- Tricharis
- Hookworm
2 nematodes that have a systemic effect
- Filaria
- Toxocara
Cestodes that affect the intestine
Tapeworms
2 cestodes that have a systemic effect
- Hydatid cysts
- Cysticercosis
Trematodes that affect the intestine
Intestinal flukes
2 trematodes that have a systemic effect
- Schistosoma
- Liver flukes
Definition of protozoa that differentiates it from bacteria and viruses
“Eukaryote” as it has genetic material encased in a nuclear membrane
Define trophozoite
Any stage in a protozoan’s life cycle which can ingest food. In practice, also refers to the motile form
Define a cyst
The non-motile form which is protected by a distinct membrane or cyst well. This is the infective stage of the parasite
Define excystation
The process of emergence of the trophozoite from the cyst
Define pseudopod
Temporary cytoplasmic processes at the surface of the trophozoite
3rd leading cause of parasitic death in the world
Entamoeba histolytica (amoebiasis)
4 stages of amoebiasis
- Asymptomatic carrier state
- Acute amoebic dysentery
- Amoebic liver abscess
- Amoeboma
Presentation of amoebic dysentery (3)
- Blood, mucousy diarrhea
- Fever
- Abdominal pain
4 ways to diagnose amoebic dysentery
- Amoebic (hematophagous trophozoites) in stool
- Mixed WBCs in stool
- Patchy inflammation seen on colonoscopy
- Stool PCR or antigen capture
Presentation of amoebic liver abscess (3)
- Persisting fever
- RUQ or epigastric pain and/or shoulder pain
- Rarely diarrhea
5 ways to diagnose amoebic liver abscess
- Ultrasound
- Raised WBC
- Serology
- Aspirate microscopy
- Response to metronidazole 750 TID
Drug for tissue entamoeba histolytica
Metronidazole
2 drugs for bowel lumen entamoeba histolytica
- Diiodochlorhydroxyquin (aka Iodoquinol, Diodoquin)
- Diloxanide furoate (Furamide)
Only source of entamoeba histolytica
Humans
*Entamoeba histolytica *transmission
Fecal-oral (poop the eggs and then eat the eggs)
Most commonly diagnosed enteric parasite in US/Canada
Giardia lamblia
Effect of *giardia lamblia *on intestinal wall
- Villus atrophy
- Crypt hyperplasia
Transmission of giardia
Fecal oral; zoonotic (most mammals, esp. beaver)
7 symptoms of giardiasis
- Diarrhea
- Flatulence
- Abdominal cramps
- Decreased appetite
- + weight loss
- + nausea
- NO fever
Basically, upper GI symptoms (colitis very unlikely dDx)
Signs of giardiasis
Mild abdominal tenderness
4 laboratory findings of giardiasis
- No leukocytes in stool
- No mucous in stool
- Giardia cysts/trophs intermittent in stool
- Girdia cysts/trophs in duodenal aspirate
Define anchovy paste and when you can find it
Aspirate of liver amoebic liver abscess
6 treatments for giardia
- Metronidazole 250 - 750 mg TID x 7 - 10 days
- Tinidazole
- Nitazoxanide
- Paromomycin
- Quinacrine (atabrine)
- Furazolidone
What is Cryptosporidium parvum an important cause of
Self-limited foodborne diarrhea worldwide
2 methods of transmission of cryptosporidium
- Zoonosis (bovine)
- Fecal-oral (i.e. by contamination of municipal water)
Location of cryptosporidium in body
Small intestine epithelial cell membrane
Type of life cycle that cryptosporidium has
Apicomplexa
2 clinical findings of cryptosporidium
- Diarrhea 2 - 3 weeks (chronic in AIDS)
- Cholecystitis