GI Worms Protozoa Diarrheals & Hepatitis Flashcards
Entamoeba Histolytica: Transmission
Fecal oral route by contamination of food or water with infective cysts
Entamoeba Histolytica: Clinical disease
Commonly asymptomatic (carrier state). Acute disease it can present as severe dysentery with numerous small stools containing blood, mucous and shreds of necrotic mucosa. Disseminated infections occur when not detected early. Primarily spreads to the liver (lung and brain possible) and is more common in immunocompromised host
Entamoeba Histolytica: Morphology (shape, # of nuclei, #of flagella, cytoplasmic appearance)
Trophozoites have ameboid shape, ground glass cytoplasm, a solitary nucleus, no flagella and often RBC inclusion bodies. Cysts are spherical with 1-4 nuclei and might contain chromatoid bodies (sausage shaped)
RBC inclusion bodies are often seen in what organsim
Entamoeba Histolytica
Acanthamoeba: Transmission
Direct contact (as with the contact lense epidemic) or inhalation
Acanthamoeba: Clinical disease
Immunocompromised: More common, causes pneumonitis (lung inflammation), dermal ulceration, and slowly progressive but fatal encephalitis. Healthy individuals: Can cause ulcerative keratitis (eats the cornea) resulting from contaminated contact lenses.
This organism was responsible for the keratitis outbreak in schools after kids started sharing their color contacts
Acanthamoeba
Naegleria fowleri: Transmission
Swimming in warm bodies of fresh water, such as ponds, lakes, rivers, and hot springs. Enters brain via olfactory route (cribriform plate)
Naegleria fowleri: Clinical disease
Affects healthy and immunocompromised individuals by causing primary amebic meningoencephalitis, a rapidly progressing and almost invariably fatal disease (the case fatality rate is estimated at 98%)
Infection with this organsim almost always results in death (98% mortality rate)
Naegleria fowleri
Giardia Lamblia: Transmission
Ingestion of infected water or by anal/oral sexual contact
Giardia Lamblia: Clinical disease
Trophozoites coat villi of small intestine, interfering with the absorption of fat, and fat soluble nutrients such as vitamin B12, carotene, and folate. Symptoms: epigastric pain and non-bloody diarrhea (steatorrhea)
Giardia Lamblia: Morphology (shape, # of nuclei, #of flagella, cytoplasmic appearance)
Trophozoite is pear shaped with sucking disk, 2 nuclei that resmble eyes and 4 pairs of flagella. Cyst is football shaped with 2-4 nuclei and axonemes
Infection with which organism is the most common (in the USA) of the intestinal protozoan infections
Giardia Lamblia
Trichomonas vaginalis: Transmission
Sexual contact, contaminated towels, wash cloths, and clothing (can survive on fomites up to 24 hours)
Trichomonas vaginalis: Clinical disease
Trophozoites feed on the mucosal surface of the vagina resulting in inflammation, vaginal irritation, burning, and purulent discharge. Infection in males may be asymptomatic and harder to detect. Prostatic inflammation is most common symptom
Trichomonas vaginalis: Morphology (shape, # of nuclei, #of flagella, cytoplasmic appearance)
Trophozoite is oval or pear shaped with 1 nucleus. Has 4 flagella, and a characteristic undulating membrane. Its axoneme appears to protrude from the posterior but is actually covered by membrane
Cryptosporidium parvum: Transmission
Ingestion of infected water or by anal/oral sexual contact
Cryptosporidium parvum: Clinical disease
Immunocompromised: An opportunistic infection seen in AIDS patients that causes chronic life threatening infection with profuse watery diarrhea. Immunocompetent: Profuse watery diarrhea that is self-limiting.
This organism is acid fast and resistant to chlorination
Cryptosporidium parvum
This organism is similar to Cryptosporidium parvum except its larger. It is also acid fast.
Cyclospora cayetanensis
Cyclospora cayetanensis: Transmission
Contaminated fruit
Which three infection-causing protozoans of the GI tract are acid fast
Cryptosporidium parvum, Cyclospora cayetanensis, Isospora belli
Isospora belli: Clinical disease
Similar to Cryptosporidium. Causes acute, non-bloody diarrhea with crampy abdominal pain, which can last for weeks and result in malabsorption and weight loss. In immunodepressed patients, and in infants and children, the diarrhea can be severe.
