exam 2 Flashcards
(163 cards)
what is an amoeba?
protozoa
do amoebas require a host to live?
-no they can be free-living
-but benefit rom the interaction
-facultative parasites
what is the amoeba that most commonly infects dogs, cats, and humans?
entamoeba histolytica
what is the amoeba that most commonly infects reptiles?
entamoeba invadens
what is the species of amoeba that usually infects humans?
acanthamoeba spp
what is the brain eating amoeba?
naegleria fowleri
what are the amoebic life stages?
- trophozoites
-amoeboid
-motile
-feeding/pathogenic - cysts
-round
-non-motile
-environmentally resistant
which amoebic life stage actively invades the tissue?
trophozoite stage
are both the cysts and trophozoites capable of being infectious/or if ingested in amoebic life stage?
yes
what are the routes of infection for amoebas?
ingested (fecal-oral)
nasal mucosa (inhaled)
eye
skin abrasions
where does the amoeba like to go once they are in the body
depends on where the infection starts
-intestinal
-extraintestinal: lung, liver, brain
what is the highway to the brain?
the olfactory portal
-brain eating amoeba
-the amoeba can go through the cribriform plate and crawl through the nerve hole plates
what is a concern for the mechanism of pathogenesis for amoebic infection in the brain?
the brain is in a fixed space so lots of pain, atrophy, and inflammation can overtime can cause detrimental effects
what do entamoeba invadens infect?
reptiles
-boas, colubrids, vipers, crotalids are most susceptible
what is the most common route of infection for entamoeba invadens?
fecal-oral
what is entamoeba invadens morphologically identical to and what is it specifically not transmissible to?
morphologically identical to E. histolytica
-not transmissible to mammals
why would you get extraintestintal signs of entamoeba invadens?
portal vein goes to the liver, causing necrosis in the liver
what is the preferred route of infection for naegleria fowler?
through the nose
treatment for amoebic infections?
metronidazole
what are the life stages of ciliates?
trophozoites and cyst
what is considered commensals in many large animals, but can rarely invade GI tract and cause disease?
ciliates
what is the causative agent of chagas disease?
trypanosoma cruzi
what is the causative agent of dourine?
trypanosoma equiperdum
what is the causative agent of nagana?
trypanosoma brucei
T. congolense
T. vivax