Protozoan Flashcards
Unicellular eukaryote with the ability to form cyst
Protozoa
Protozoal stage that is dormant and highly resistant to environmental stress. Typically causes disease in the mode of infection.
Cyst stage
Protozoal stage that is active, reproductive, and feeding. It is the form that typically causes disease in humans.
Trophozoite stage
Protozoan most commonly transmitted by the ingestion of amebic cysts from fecally contaminated food or water.
Amebiasis (Entamoeba histolytica)
How do most infections of Entamoeba histolytica present?
Asymptomatically
Where does Entamoeba histolytica usually spread in the body and cause destruction?
Gastrointestinal System
Entamoeba histolytica has a 2 - 4 week incubation period in the gastrointestinal system, after that it causes what symptoms?
Bloody diarrhea
Abdominal Pain
Colitis
Fever
What might Intestinal Amebiasis progress to?
Necrotizing Colitis
- mucosal sloughing
- severe hemorrhage
Amebiasis can become severe and spread outside of the intestines. Where is it most likely to spread to?
Liver
Once Entamoeba histolytica spreads to the liver, what may develop?
Amebic Liver Abscess
- fever
- RUQ pain
- hepatomegaly
- high fever
(more commonly only one abscess)
What is the preferred diagnostic method for Intestinal amebiasis?
Stool PCR
How is Entamoeba liver abscess typically identified?
Ultrasound
CT
MRI
What is the treatment for Entamoeba histolytica?
Metronidazole or Tinidazole + Luminal agent
A needle aspiration of a large hepatic abscess caused by Entamoeba histolytica is required when the abscess reaches what size?
Over 5 - 10cm
Free living ameba with a flagellate form that is thermophilic and found in: soil, fresh and polluted warm lake water, domestic water supplies, swimming pools, thermal water, and sewers.
Naegleria fowleri
Aspiration of contaminated water or soil containing Naegleria flowleri causes what?
Primary Amebic Meningoencephalitis (PAM)
- Rapidly fatal
What is the most common protozoan parasite infection in the United States?
Giardia Lamblia
What age group is most commonly infected with Giardia Lamblia?
Young Children
How is Giardia Lamblia most commonly transmitted?
Contaminated water from remote streams, surface wells, or lakes.
(Backpacker’s Diarrhea)
What percentage of people develop symptoms when infected with Giardia Lamblia?
25 - 50%
What are the symptoms of Giardia Lamblia infection?
Profuse Watery Diarrhea
Greasy, Frothy, Foul Smelling Stools (Steatorrhea)
- can last days or weeks
What is the preferred diagnostic method for Giardia Lamblia?
PCR Stool Assay
What is the drug of choice for Giardia Lamblia?
Metronidazole or Tinidazole
Paramomycin (pregnancy)