Unit 1 - Apicomplexa Flashcards
Common, can infect many vertebrates, and can cause multi-systemic disease…but can also be covert
T. gondii
What is the definitive host of Toxoplasma gondii?
felidae (all cat species)
What are the intermediate hosts for T. gondii?
almost all warm-blooded animals
What are two routes of infection for T. gondii?
- ingestion of tissue cysts in IH (3-10 days)
- ingestion of sporulated oocysts (19-48 days)
What protozoal stages of T. gondii can be seen in felids?
- sexual stages in intestine fertilization –> unsporulated oocysts shed
- asexual stages extra-intestinal
What is the PPP (pre-patent period)?
time from infection until demonstration of oocysts in feces
What is the most efficient route of infection for T. gondii?
ingestion of tissue cysts from intermediate hosts (3-10 days)
When is peak oocyst shedding of T. gondii?
6-7 days PI
What are the symptoms of T. gondii is adults cats?
usually subclinical
What are the symptoms of T. gondii in kittens?
feline toxoplasmosis (concurrent infection, immunosuppression) - fever, weight loss, lethargy, dyspnea, abdominal discomfort, icterus, etc.
What is the big picture behind T. gondii clinical signs?
multisystemic; primarily lungs, liver, ocular
What effect does T. gondii have on sheep?
major cause of abortions in US, vertical transmission (infected offspring)
How does T. gondii affect goats?
abortions, clinical toxoplasmosis (liver, kidneys, CNS), vertical transmission
Is there a transmission risk of T. gondii for people?
yes; raw goat milk, undercooked meat
How does T. gondii affect cattle and horses?
resistant to infection
What does it mean if an animal is seropositive for an infection, i.e. T. gondii?
gives a positive result in a test of blood serum
What about clinical toxoplasmosis and vertical transmission of T. gondii in dogs?
both are rare
Will a fecal float detect T. gondii?
rarely detects oocysts
How do you diagnose an active infection of T. gondii FelidDH?
rising titer (4-fold increase over two weeks)
How can you diagnose T. gondii in IH?
clinical signs, antibody titers, PCR, histo, immunohisto
What are the approved treatments for T. gondii?
no vaccines or drugs
What are some off-label options for treating T.gondii?
clindamycin, sulfonamide & pyrimethamine, trimethoprim & sulfonamine
What are the control methods of T. gondii?
remove feces daily, feed cats dry/canned/cooked meat only, prevent carnivorism/hunting
What is the direct host of Neospora caninum?
dogs
What does N. caninum cause in dogs?
neuromuscular disease
What are the IH for N. caninum?
cattle (also, small ruminants, deer, horses, etc.)
What is the primary cause of cattle abortion worldwide?
N. caninum
What’s a prevalent similarity between N. caninum and T. gondii?
excreted as unsporulated oocysts from the host, sporulates in the environment, cysts in intermediate host
What’s the major different between T. gondii and N. caninum?
dogs can get reinfected, cats cannot
What is the PPP of N. caninum?
5-17 days
How long does it take N. caninum oocysts to sporulate in the environment?
24-72 hours
Once N. caninum sporulates, how many sporocysts does it have? Sporozoites?
2 sporocysts, 4 sporozoites
What are the 2 routes of infection for the IH?
oocyst, transplancental
What are the two routes of infection for the DH?
ingestion of tissue cyst, transplacental
Congenital infection with N. caninum leads to….
asymptomatic carriers
Describe the lesions seen with Neospora caninum:
focal necrosis to severe myositis in skeletal muscles
What are some clinical signs you might seen in a dog that’s come into your clinic with Neospora caninum?
progressive hind limb paralysis, muscle atrophy, difficulty swallowing
When diagnosing N. caninum, what can be seen on a fecal float?
unsproulated oocysts (short period of time)
How do you test for N. caninum in cattle?
antibody test using serum or milk (ELISA); multiple testing (can use aborted calves - hist, PCR, ELISA)
What are the methods of control for N. caninum?
limited access of dogs to cattle, minimization of fecal contamination, remove aborted cattle, herd management
What are the approved treatments for N. caninum?
None; no Vx
What off-label drugs are used for treating clinical neosporosis?
clindamycin; trimethoprim sulfadiazine with pyrimethamine
What is the clinical significance of Hammondia?
must be distinguished from toxoplasma, neospora
What differentiates Hammondia from Neospora and Toxoplasma?
non-pathogenic, no extra-intestinal stage in DH, infects IH ONLY via ingestion of oocysts, infects DH ONLY via ingestion of tissue cysts
Hammondia heydorni DH? IH?
dogs, coyotes; herbivores
Hammondia hammondi DH? IH?
cat; mammals, birds
Hammondia site of infections for DH? IH?
DH: intestinal tract only
IH: throughout entire body
List the species that sporulate outside the host (5):
T. gondii, Hammondia, Isospora, Eimeria, Neospora
How many sporocysts does the Hammondia oocyst have? Sprozoites?
2 sporocysts; 4 sporozoites
In Sarcocystis spp., what is the definitive host and the intermediate host (think generally)?
predator - DH; prey - IH
Do Sarcocystis spp. have a direct or indirect life cycle?
indirect
What is the PPP of Sarcocystis in the DH?
7-14 days
What kind of reproduction occurs in the DH of Sarcocystis spp?
sexual - gametogony
What kind of reproduction occurs in the IH of Sarcocystis spp?
asexual - merogony
List the DH for Sarcocystis cruzi:
dogs, wolves, coyotes, raccoons, foxes, hyenas
List the IH for Sarcocystis cruzi:
cattle, ox, bison
What is the infective stage of S. cruzi to the DH:
sarcocyst (with bradyzoites)
What is the infective stage of S. cruzi to the IH:
oocyst/sporocysts
What is the route of infection of S. cruzi for the DH?
ingestion of tissue cyst (sarcocyst) containing bradyzoites
What is the route of infection of S. cruzi for the intermediate host?
ingestion of oocysts/sporocysts in environment
S. cruzi site of infection DH:
intestinal tract
S. cruzi site of infection IH:
extraintestinal - heart, skeletal muscle, tongue, esophagus, diaphragm
In its DH, S. cruzi is:
asymptomatic, no immunity
The clinical symptoms of S. cruzi in its IH are:
acute, anorexia, pyrexia, anemia, weight loss, abortion in final trimester
Diagnosing S. cruzi in IH is done using:
- clinical signs
- presence of sarcocyst on histology (up to 1 cm long, cylindrical)
- antibody detection
Diagnosing S. cruzi in DH is done using:
- sporocysts/oocysts on fecal float (normally JUST the free sporocysts)
- oocyst is approx. double the sporocyst size
Treatment of S. cruzi in the IH is:
prophylactc (amprolium, salinomycin, deccox, monensis, stenoral)
Control Measures against S. cruzi (4):
- predator/prey control
- avoid fecal contamination by carnivores
- avoid feeding dogs uncooked meat
- bury or incinerate dead livestock
What is the DH for S. neurona?
opossums
What are the IH for S. neurona?
armadillo, raccoon, cat, skunk, etc.
What is the AH for S. neurona?
horse
An agent of equine protozoal myeloencephalitis (EPM):
Sarcocystis neurona
What stage of the S. neurona lifecycle is infective to the DH?
sarcocyst (with bradyzoites) in an intermediate host
What stage of the S. neurona life cycle is infective to the IH?
sporocyst, oocyst
What stage of the S. neurona life cycle is infective to the AH?
sporocyst, oocyst
What is the site of infection for S. neurona in the DH?
intestinal tract
What is the site of infection for S. neurona in the IH?
skeletal muscle, tongue
What is the site of infection for S. neurona in the AH (horse)?
CNS
What are the clinical signs for the DH and IH of S. neurona?
none; asymptomatic
How do you diagnose S. neurona in the DH?
oocyst/sporocysts on fecal flotation
How do you diagnose S. neurona in the IH?
sarcocyst on histology, IFA. PCR
Describe the pathology for S. neurona in horses (AH):
gross lesion confined to neural tissue, histologically
What are the rule outs for S. neurona in horses (7)?
Neospora hughesi, equine herpes virus, lyme disease, west nile virus, cushing disease, Se deficiency, orthopedic lameness
How do you diagnose EPM in a horse (S. neurona)?
complete neurologic exam, equine CSF/blood tests (western blot, pcr, ifat, elisa)
What is the problem with diagnosing S. neurona in horses?
can’t reproduce, varies widely, and the organism is difficult to detect
What are the FDA approved drugs for treating S. neurona EPM?
ponazuril, diclazuril, combo sulfadiazine and pyrimethamine
Can relapses occur with S. neurone EPM?
yes
How do you control S. neurona EPM?
protect feed/water sources from opossum
reduce road-kill around farm
When are horses at increased risk for S. neurona?
summer, spring, fall; presence of opossum/wooded areas, age, stress
How to prevent Sarcocystis spp. infections in humans?
cook meat thoroughly, avoid fecal contamination of water/food
How do humans get Sarcocystis hominis infections?
beef with sarcocysts
How do humans get Sarcocystis suihominis infections?
pork with sarcocysts
Site of Cryptosporidium spp.
primarily GI (but can be seen in resp. tract; bursa/proventriculus of birds)
Do Cryptosporidium spp. have a direct or indirect life cycle?
direct
What is the infective stage of Cryptosporidium spp.?
sporulated oocyst
Where do Cryptosporidium spp. sporulate?
within the host
What are the routes of infection for Cryptosporidium spp.?
fecal-oral, autoinfection
How is Cryptosporidium transferred?
contaminated water/feed, aerosol, mechanical transport
What is the PPP for Cryptosporidium spp?
1 week of less
What is the PPP for Cryptosporidium parvum?
3-6 days
Common cause in intestinal disease in neonatal ruminants (1-4 weeks old):
Cryptosporidium parvum
C. parvum site of infection in cattle:
ileum
C. parvum PPP in cattle:
3-6 days
What is the Patent period of C. parvum in cattle?
1-2 weeks (self-limiting)
Clinical signs of C. parvum in cattle (3):
diarrhea, depression, anorexia
Pathology of C. parvum in cattle (5):
loss of epithelial cells, villus atrophy, dehydration, electrolyte imbalance, impaired nutrient digestion, absorption
Mature cattle site of infection for C. andersoni:
abomasum
Are there any clinical signs associated with Cryptosporidium andersoni in mature cattle?
no
Abomasal pathology of C. andersoni (4):
dilation of peptic glands, hypertrophy of gastric mucosa, thinning of epithelium, impaired protein digestion
Cryptosporidium species typically seen in puppies <6 months old:
canis
What’s are 2 similarities between C. canis and C. felis
both are rarely associated with disease; diarrhea, anorexia, weight loss
For Cryptosporidium spp. diagnosis, what do you use to detect oocysts (4)?
sugar float, modified acid fast, fluorescent antibody test, PCR
Cryptosporidium oocyst morphology:
4-6 um, no sporocyst, 4 sporozoites, sporulates in host
Cryptosporidium treatment:
No efficacious tx, fluid & electrolyte replacement (maintenance)
Cryptosporidium control:
management strategies, clean up environment (formaldehyde & chlorine solutions, steam cleaning, dilute with washing, dessication)
Which Cryptosporidium species infect birds?
meleagridis (turkeys, humans), baileyi (poultry), galli (finches, chickens)
Hammondia oocysts have the same size range as what two other protozoans?
toxoplasma, neospora
What is the PPP for Hammondia?
1 week
How long is Hammondia patent for?
1-2 weeks
What is the DH for Neospora hughesi?
unkown
What is the IH for Neospora hughesi?
horse
How is N. hughesi transmitted?
transplacental
What are two cutaneous Leishmaniasis diseases?
tropica, Mexicana (& braziliensis)
What are the two visceral forms of Leishmaniasis?
donovani complex, infantum (U.S. foxhounds)
What is the vector for the Leishmania spp.?
sand flies
Vertebrate host for L. infantum in the U.S.:
foxhounds (endemic in many kennels)
Insect vector for L. infantum in US:
None identified
Reservoir host for L. infantum in US:
dogs
Transmission routes between dogs for L. infantum in the US:
direct vertical & horizontal (biting, behavioral, reused needles, venereally, transfusions, etc.)
First clinical signs of canine leishmaniasis:
facial alopecia, nodular skin lesion/ulcers
What is the PPP for canine leishmaniasis?
can be a very quick onset or prolonged
Serology for canine leishmaniasis:
IFA, ELISA, K-39-immunoassay
Staining locations to look for Canine leishmaniasis amastigotes:
bone marrow, lymph node aspirates, blood, touch preps
Detecting leishmaniasis in other hosts:
sand fly vector: promastigotes
What’s the vector for Trypanosoma cruzi?
triatomine insect (nose/kissing bug)
The triatoma spp. was reported positive for what protozoa in the U.S.?
Trypanosoma cruzi
T. cruzi life cycle stages:
single, large mitochondria (kinetoplast), undulating membrane & single nucleus
What two morphologies can T. cruzi be?
either elongate with a single flagellum or rounded with a short, nonprotruding flagellum
Route of infection for triatomine insect:
ingest trypomastigotes in triatomine feces enter wound/mucosal membrane
Routes of infection for vertebrate host of T. cruzi:
- via triatomine insect vector
- transplacental
- blood (transfusion, needles; organ transplant)
Confirmed (cultured) vertebrate hosts for T. cruzi:
dogs, opossums, wood rats, armadillos, raccons, mice, squirrels, grey fox
Seropositive vertebrate hosts for T. cruzi:
cats, moles, bats, feral hogs, bobcat, badger, coyotes, wild mice species
Dogs are a reservoir host for T. cruzi and are typically:
asymptomatic
Acute Chagas disease clinical signs in dogs:
10-30d; fever, anorexia, diarrhea, lethargy, enlarged organs, cardiac dysfunction, death
Chronic Chagas disease clinical signs in dogs:
eventual congestive heart failure
Latent Chagas disease clinical signs in dogs:
asymptomatic, low level infection, lasts for years
Can cats get Chagas disease?
yes, but extremely rare
How do you identify T. cruzi in blood smears?
giemsa stain: trypomastigotes (C-shape)
What methods of diagnostics can you use for T. cruzi?
blood smear, histo, culture (blood), serology
What’s often seen in chagas histology/biopsy?
amastigotes in cardiac tissue