exam 2 Flashcards
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
what is the causative agent of surra?
trypanosoma evansi
what is the causative agent of canine leishmaniasis?
leishmania infantum
what is salivarian trypanosomes
transmitted by bite of vector
what is stercorarian trypanosomes
transmitted by feces of vector
what species of trypanosomes transmit transplacentally?
T. cruzi
how is nagana disease transmitted?
through bites of tsetse flies
what animal does nagana disease affect?
domestic ruminants
acute nagana disease
high parasitemia with extensive hemorrhages of mucosa and serosal surfaces of body
chronic nagana disease
cattle become anemic and emaciated with signs of severe wasting
what tse-tse transmitted causes disease in horses, cattle, buffalo, sheep, and goats
T. vivax South America
what disease is caused by a non-tsetse vectored trypanosome
surra disease
what animals does surra disease infect?
domestic animals
what are the vectors for surra disease?
tabard flies
vampire bats
what are the clinical signs of surra disease
-no pathognomonic signs Orr macroscopic lesions
-in horses fever, weight loss, lethargy, etc
how does transmission occur in dourine disease?
through direct sexual contact
what is a distinct sign in the acute stage of dourine disease?
edematous patches (silver dollar plaques)
chronic stage of dourine
emaciation
paresis
intermittent fever
death
clinical diagnosis of nagana disease
blood smear
serological test
clinical diagnosis of surra disease
blood smear
PCR
serology
clinical diagnosis of dourine
clinical signs
serology
how to prevent dourine disease?
they need to be quarantines and tested by serology when new animals being introduced into herd
what is American trypanosomiasis
chagas disease
caused by T. cruzi
what are reservoir hosts for American trypanosomiasis
opossums, armadillos, rodents, cats, pigs, raccoons, monkeys
routes of infection for chugs disease?
vector borne
triatomine (kissing) bug
where is canine chagas disease increasingly reported?
southern US, Texas
what are the at risk populations for chagas disease?
working dogs
young
diseases moms
outdoor dogs
acute chagas disease
fever, anorexia, lethargy, lymphadenopathy, etc
latent chagas disease
no clinical signs
chronic chagas disease
congestive heart failure
dilated cardiomyopahty
arrhythmias
diagnosis of chagas disease
serology
ECG findings
*have to find in acute phase
treatment of chagas disease
no effective drugs
leishmania is a protozoan parasite that causes what disease?
leishmaniasis
what animal are the species that are most often affected by leishmaniasis
dogs
vector/mode of transmission of leishmaniasis
sand flies
what is the most common cause of canine leishmaniasis
leishmania infantum
what is the main reservoir host for human visceral leishmaniasis caused by L. infantum?
dogs
zoonotic
life cycle of leishmania infantum
sandfly takes blood meal from host
injects parasites (salvarian trans)
parasite goes into macrophage and develop and multiply in immune cells and macrophage
lyse then reinfect more macrophages
sandflies feed and develop inside, repeat
cutaneous leishmaniasis manifests as
-manifests as alopecia, scaling, and/or ulceration but can be nodular or papular
-many dogs develop onychogryphosis (long claws)
visceral leishmaniasis
cutaneous form
development of autoantibodies and circulating immune complexes (attack tissues)
diagnosis of canine leishmaniasis
microscopy (gold standard)
serology
PCR
what are the life stages of Giardia and which one is the infective stage?
trophozoite
cyst (infective stage)
what is a key characteristic of Giardia cysts
thick-walled cyst, infective stage shed in feces
contain 4 nuclei when mature
giardia duodenalis is subdivided into 8 genetic assemblages to what?
identify the type of host
what is the transmission of Giardia duodenalis
direct ingestion of fecal giardia cysts
explain variant-specific surface protein
there is only one type of VSP found on trophozoite surface except during differentiation and switching
-VSP receptors will switch surface coat so immune response will not recognize
where are the trophozoites found in when Giardia cysts are ingested in dogs and in cats?
-trophozoites are found from the duodenum (releasing two trophozoites in duodenum) to the ileum of dogs
-but predominant in the jejunum and ileum of cats
what is the pre patent period for giardia for cats and dogs?
cats- 5-16 days
dogs- 4-12 days
what is the structural difference between giardia trophozoites and cyst
-trophozoites have the piriform shape (tear drop) with the two nuceli
where is giardia is most often observed?
in young animals, where illness is typically more severe and persistent
what is a common/unique way to identify that a dog/cat has giardia based off symptoms?
-they have foul and greasy stool
-mucoid, malodorous, light colored stool that may contain fat
what is the genus that causes giardiasis in birds?
giardia psittaci
psittacine birds, parrots
in what species of bird does most clinical cases of giardiasis occur?
budgerigars and cockatiels (they have poor growth and high mortality)
does giardia duodenalis have a zoonotic potential when infection originates in domestic animals?
yes
public health risk
what is the best way to diagnose giardiasis?
*zinc sulfate floatation
-microscopic examination fresh
-fecal immunoassays
-fecal PCR
what diagnostics detect motile trophozoites in giardia?
direct saline smear
where are trichomonads usually found?
where there is very little oxygen, like GI and urogenital tract
what are key structures in trichomonads?
axostyle
undulating membrane
anterior flagella
is the wall of the trichomonads cyst thick or thin?
thin walled
-thick-walled cyst stage are absent from the life cycle
what causes bovine trichomonosis, a venereal disease of cattle?
tritrichomonas foetus
(in the reproductive tract)
what are the disease patterns of bovine trichomoniasis in males and females?
males: asymptomatic
females: infects the vagina, uterus, uterine tubes, it gets cleared by end of breeding season but can reoccur again
what are the diagnostics of bovine trichomoniasis?
-trophozoites sample or culture
culture- InPouch
treatment for bovine trichomoniasis
none are safe and effective
ipronidazole (but causes injury site abscessation)
what causes feline trichomoniasis in cats?
tritriichomonas blagburni
how is tritrichomonas balgburi transmitted
fecal-oral
where is feline trichomoniasis most commonly found in the body?
colon, ileum
what is the most common sign of feline trichomoniasis?
chronic diarrhea that may contain blood or mucus
how to diagnose feline trichomoniasis?
-trophozoites in fecal sample or culture
-culture InPouch feline
what is the treatment for feline trichomoniasis?
none currently approved by FDA
ronidazole (no approved in companion animal, banned food animals bc neurotoxic)
what species does pentatrichomonas hominis infect, where in the body, and how is it transmitted?
-primates, canids, felids, rodents, swine
-large intestine
-fecal-oral transmission
what causes canine trichomoniasis?
pentatrichomonas hominis
how would you treat canine trichomoniasis?
metronidazole
how would you diagnose canine trichomoniasis?
microscopy (preferred method)
culture
PCR
what species does histomonas meleagridis affect and where does it infect?
infects avian ceca, can spread to the liver
galliform birds- severe diseases in domestic turkey and some wild species
what are the two morphological forms of histomonas melegridis?
they are pleomorphic (variety of morphology)
-flagellated luminal form
-amoeboid tissue dwelling form
how is histomonas meleagridis transmitted?
-cecal nematode Heterakis gallinarum; intermediate host/vector of H. meleagridis
-cloacal drinking, intake of fluids through cloaca
how would you diagnose histomonas meleagridis (histomoniasis)?
gross pathology of ceca and liver
microscope exam
PCR
what are the unique disease patterns for histomoniasis?
-necrotic lesions on cecal wall and surface of the liver
-cecal perforation and peritonitis
-blackhead
what causes trichomoniasis and what species ?
-trichomonas gallinae
-columniform birds (pigeons and doves) the main hosts
where does trichomonas gallinae infect? how is it transmitted?
-upper digestive tract (canker); liver, other organs
-infected crop milk
what are the diagnostics of trichomoniasis?
gross pathology
microscopic exam
culture InPouch
PCR
what are the causes of trichomoniasis in captive reptiles?
intestinal trichomonads are common in captive reptiles
may cause enteric disease
what is special about the cryptosporidium lifecycle?
during fertilization they produce thick and thin walled oocysts
the thin walled ones cause auto-infection
what is the gastrointestinal cryptosporidiosis disease cause?
gastroenteritis
genus of cryptosporidium in ruminants
C. parvum
genus of cryptosporidium in poultry
C. baileyi
what genus is respiratory cryptosporidiosis seen in?
C. baileyi
avian hosts
what does eimeria spp have the biggest impact on?
ruminants and poultry
what is the predilection site for E. tenella
cecum
what does the eimeria spp infect?
GI tract
enterocytes
cells within the lamina propria
how is emieria spp transmitted?
fecal-orally
what differs about the eimeria spp life cycle?
direct life cycle
the enteric lifecycle occurs inside the host and sporogony occurs outside of the host
disease patterns for eimeria-induced coccidiosis
enteritis
diarrhea that may be bloody
what are the cattle and poultry genus of eimeria spp
E. bovis
E. tenella
how to diagnose eimeria-induced coccidiosis
fecal float (preferred method)
what is the anticoccidial drug?
amprolium
prevention for eimeria-induced coccidiosis?
vaccines
live for chickens, turkeys
nonliving for chickens
how is cystoisospora spp transmitted?
fecal-oral
basics of the lifecycle in cystoisospora spp
direct life cycle with fecal oral transmission + transmission via paratenic host
where does the cystoisospora spp enteric and exogenous sporulation occur?
enteric cycle happens inside of the gut and the exogenous sporulation happens ( poop)
swine genus cystoisospora
C. suis
dog genus cystoisospora
C. canis
cat genus cystoisospora
C. felis
C. rivolta
definitive host for toxoplasma gondii
felids
how do the toxoplasma gondii definitive hosts get infected?
felid typically get infected by eating tissue cysts harbored by infected intermediate hosts
where does the enteric cycle happen in toxoplasma gondaii
in the definitive host- felids
schizogeny, gametogeny in felid enterocytes then shed in feces
where does sporogeny occur in toxoplasma gondii
in the external environment
occysts sporulate exogenously; infective to intermediate hosts and felids
where does the extra-enteric cycle occur in toxoplasma gondii
happens in intermediate hosts
-develop in and rupture out of SI
tachyzoites explode causing acute toxoplasmosis, goes everywhere
*can also infect placenta and fetus
what happens overtime in the intermediate hosts in toxoplasma gondii
overtime, tachyzoites form tissue cysts containing bradyzoites which is infective to both felids and *intermediate hosts
tissue cyst phase toxoplasma gondii
chronic toxoplasmosis, life-long infection and can reactivated to acute toxoplasmosis
can the extra-enteric cycle also occur in felids?
yes
treatment for toxoplasmosis
acute signs- clindamycin, etc
chronic-there is no treatment that eliminates bradyzoites
life-long infection
definitive host of neospora caninum
dogs
intermediate host of neospora caninum
cattle, deer, and other mammals
is neosporosis life-long
yes
tissue damage and inflammation is caused by tachyzoites and tissue cyst
can cross placenta
neosporosis in dogs
subclinical infection typical
hindlimb paralysis if disease occurs
neosporosis in cattle
major cause of abortion
transplacental transmission, fetus autolyzed
treatment for neosporosis
dogs: clindamycin
cattle: no treatment
definitive host for sarcocystics spp
-carnivorous and omnivorous mammals
-ingestion of tissue cysts (sarcocysts) in striated muscle of infected intermediate hosts
sarcocystis spp genus that various mammals serve as intermediate hosts
S. neurona
enteric cycle in sarcocystis spp
enteric cycle –> oocysts (endogenous sporulation)–> sporocysts shed in feces
when intermediate hosts of sarcocystis spp ingest sporocysts, the extra enteric cycle occurs
just a fact
what causes equine protozoal myeloencephalitis (EPM) and what is the definitive host?
S. neurona
opossums are definitive host
dignosis for sarcocystosis
serologic test
for EPM common to test CSF for antibodies
piroplasmids are obligate _____ parasites
intracellular
who are the intermediate hosts of piroplasmids
mammals, birds
life cycle of prioplasmids
tick - gametogeny, fertilization and sporogeny
vertebrae- schizogeny
definitive host of piroplasmids
ticks
what species causes canine babesiosis
B. canis
B. gibsoni
what species causes bovine babesiosis
B. bigemina
B. bovis
why is babesiosis diagnosis ID of piroplasms not the best option
because parasitemia (content of parasites) are low in the blood
what species causes equine theileriosis
T. equi
what species causes bovine theileriosis
T. parva
main vector of cytauxzoon felis
amyblyomma americanum
definitive host of haemosporids
biting flies
intermediate host of haemosporids
tetrapod
what species cause plasmidiosis in poultry
P. gallinaceum
P. relictum
what leeucocytozoon spp cause disease ini domestic and wild birds
L. simondi
L. smithi
what haaemoproteus spp are associated with clinical disease in birds
H. lophortyx
H. meleagridis
