Amoeba & Ciliates

Question 1

what are amoeba?

Answer 1

protozoa, infects wide variety of species (inc. humans)

Question 2

Are amoeba facultative or obligate parasites?

Answer 2

facultative
aka do NOT require host to live, just feed

Question 3

what are the most important amoeba in vet med?

Answer 3

Entramoeba histolytica
Entramoeba invadens
Ancanthamoeba spp
Naegleria fowleri

Question 4

Entramoeba histolytica affect which species?

Answer 4

dogs, cats, humans

Question 5

Entramoeba invadens affects which species?

Answer 5

reptiles

Question 6

Acanthamoeba spp affect which species?

Answer 6

humans, can rarely affect vet species

Question 7

Naegleria fowleri affects which species?

Answer 7

humans, primates, cattle

Question 8

what are the two life stages of amoeba?

Answer 8

trophozoites
cysts

Question 9

what life stages of an Amoeba are infective?

Answer 9

cysts - ingestion
trophozoites - ingestion and active tissue invasion

Question 10

what are the amoeba routes of infection

Answer 10

fecal-oral
nasal mucosa (inhaled)
eye (ocular)
skin abrasions

Question 11

what parts of the body can amoeba effect?

Answer 11

intestinal, extraintestinal, liver, lung, brain

Question 12

are amoeba infections often symptomatic or asymptomatic?

Answer 12

asymptomatic

Question 13

what population is most susceptible to amoeba infections?

Answer 13

young and immunocompromised

Question 14

which nerve/portal allows movement of amoeba to the brain?

Answer 14

olfactory portal that has olfactory nerve - amoeba crawls up nerve

Question 15

what are the mechanisms of amoebic infection pathogenesis?

Answer 15

malabsorption
direct tissue destruction
incite inflammatory response

Question 16

who is Entamoeba invadens NOT transmissible to?

Answer 16

mammals

Question 17

what species are reservoir hosts for Entamoeba invadens?

Answer 17

chelonians (turtles), crocodilians, cobras, eastern king snakes
reptiles that are resistant

Question 18

which reptiles are most susceptible to Entamoeba invadens?

Answer 18

boas, colubrids, vipers, crotalids

Question 19

which amoeba causes transmural necrohemorrhagic in snakes?

Answer 19

Entemoeba invadens

Question 20

what are clinical signs of Entamoeba invadens?

Answer 20

anorexia, V, mucoid/hemorrhagic D, sudden death

Question 21

Loss of ___ predisposes reptiles with Entamoeba invadens to sepsis

Answer 21

intestinal barrier

Question 22

what type of Entamoeba invadens is this?

Answer 22

intestinal
Transmural necrohemorrhagic colitis

Question 23

what is seen with intestinal Entamoeba invadens?

Answer 23

transmural necrohemorrhagic colities

Question 24

what is seen with extraintestinal Entamoeba invadens?

Answer 24

Enterocolitis -> subsequent hepatitis following hematogenous dissemination via portal vein
necrotizing hepatitis

Question 25

what is a unique site of infection in humans of Acanthamoeba spp. in humans?

Answer 25

eyes don't rinse contact lens with tap water -> infection -> blind

Question 26

what's the main transmission mode of Naegleria fowleri?

Answer 26

inhalation

Question 27

can you get infected by swallowing water contaminated with Naegleria?

Answer 27

NO, has to go up nose to establish infection

Question 28

which protozoa has a free-living flagellate form?

Answer 28

Naegleria fowleri

Question 29

what can Naegleria fowleri cause?

Answer 29

Primary amoebic meningoencephalitis (PAM) brain and meninges inflammation

Question 30

ID the issue caused by Naegleria fowleri

Answer 30

primary amoebic meningocephalitis (PAM)

Question 31

what's the drug of choice for amoeba? why?

Answer 31

Metronidazole inhibits DNA synthesis cannot be used in food animals

Question 32

How many life stages do Ciliates have?

Answer 32

has TWO life stages (trophozoite and cyst)

Question 33

what are the physical characteristics of Ciliates?

Answer 33

cilia are all around dimorphic nucleus macronucleus >1 micronuclei

Question 34

Are ciliates pathogenic or non-pathogenic mostly?

Answer 34

mostly non-pathogenic/commensal rarely cause disease

Question 35

is this amoeba or ciliate?

Answer 35

ciliate

Question 36

what is a ciliate with zoonotic potential?

Answer 36

Balantidium coli

Question 37

what is the reservoir host of Balantidium coli?

Answer 37

pigs

Question 38

describe the trophozoite stage of amoeba

Answer 38

amoeboid motile ***feeding/pathogenic stage***

Question 39

describe the cyst stage of amoeba

Answer 39

round non-motile ***environmentally resistant, transmission***

Question 40

Are amoebas or ciliates considered a part of the normal flora in forestomachs of ruminants and hindgut of horses?

Answer 40

ciliates

Question 41

what are the varying disease phenotypes for amoebas?

Answer 41

asymptomatic to sudden death intestinal (widespread) to extraintestinal (systemic)