Amoeba & Ciliates COPY Flashcards
what are amoeba?
protozoa, infects wide variety of species (inc. humans)
Are amoeba facultative or obligate parasites?
facultative
aka do NOT require host to live, just feed
what are the most important amoeba in vet med?
Entramoeba histolytica
Entramoeba invadens
Ancanthamoeba spp
Naegleria fowleri
Entramoeba histolytica affect which species?
dogs, cats, humans
Entramoeba invadens affects which species?
reptiles
Acanthamoeba spp affect which species?
humans, can rarely affect vet species
Naegleria fowleri affects which species?
humans, primates, cattle
what are the two life stages of amoeba?
trophozoites
cysts
what life stages of an Amoeba are infective?
cysts - ingestion
trophozoites - ingestion and active tissue invasion
what are the amoeba routes of infection
fecal-oral
nasal mucosa (inhaled)
eye (ocular)
skin abrasions
what parts of the body can amoeba effect?
intestinal, extraintestinal, liver, lung, brain
are amoeba infections often symptomatic or asymptomatic?
asymptomatic
what population is most susceptible to amoeba infections?
young and immunocompromised
which nerve/portal allows movement of amoeba to the brain?
olfactory portal that has olfactory nerve - amoeba crawls up nerve
what are the mechanisms of amoebic infection pathogenesis?
malabsorption
direct tissue destruction
incite inflammatory response
who is Entamoeba invadens NOT transmissible to?
mammals
what species are reservoir hosts for Entamoeba invadens?
chelonians (turtles), crocodilians, cobras, eastern king snakes
reptiles that are resistant
which reptiles are most susceptible to Entamoeba invadens?
boas, colubrids, vipers, crotalids
which amoeba causes transmural necrohemorrhagic in snakes?
Entemoeba invadens
what are clinical signs of Entamoeba invadens?
anorexia, V, mucoid/hemorrhagic D, sudden death
Loss of ___ predisposes reptiles with Entamoeba invadens to sepsis
intestinal barrier
what type of Entamoeba invadens is this?
intestinal
Transmural necrohemorrhagic colitis
what is seen with intestinal Entamoeba invadens?
transmural necrohemorrhagic colities
what is seen with extraintestinal Entamoeba invadens?
Enterocolitis -> subsequent hepatitis following hematogenous dissemination via portal vein
necrotizing hepatitis
what is a unique site of infection in humans of Acanthamoeba spp. in humans?
eyes
don’t rinse contact lens with tap water -> infection -> blind
what’s the main transmission mode of Naegleria fowleri?
inhalation
can you get infected by swallowing water contaminated with Naegleria?
NO, has to go up nose to establish infection
which protozoa has a free-living flagellate form?
Naegleria fowleri
what can Naegleria fowleri cause?
Primary amoebic meningoencephalitis (PAM)
brain and meninges inflammation
ID the issue caused by Naegleria fowleri
primary amoebic meningocephalitis (PAM)
what’s the drug of choice for amoeba? why?
Metronidazole
inhibits DNA synthesis
cannot be used in food animals
How many life stages do Ciliates have?
has TWO life stages (trophozoite and cyst)
what are the physical characteristics of Ciliates?
cilia are all around
dimorphic nucleus
macronucleus
>1 micronuclei
Are ciliates pathogenic or non-pathogenic mostly?
mostly non-pathogenic/commensal
rarely cause disease
is this amoeba or ciliate?
ciliate
what is a ciliate with zoonotic potential?
Balantidium coli
what is the reservoir host of Balantidium coli?
pigs
describe the trophozoite stage of amoeba
amoeboid
motile
feeding/pathogenic stage
describe the cyst stage of amoeba
round
non-motile
environmentally resistant, transmission
Are amoebas or ciliates considered a part of the normal flora in forestomachs of ruminants and hindgut of horses?
ciliates
what are the varying disease phenotypes for amoebas?
asymptomatic to sudden death
intestinal (widespread) to extraintestinal (systemic)
