Card Set Information
resting form in tissue cysts
resting form, may be passed in feces
passed in feces
Who does Giardia affect?
anything that is mammal
What species can serve as reservoirs in nature for Giardia?
Is there an intermediate host for Giardia?
Where does Giardia infect its host?
What clinical signs are there with Giardia infection?
What is the infective form of Giardia?
How does Giardia enter the body?
through food or water
What is the prepatent period of Giardia?
1 - 2 weeks
How is Giardia diagnosed?
trophozoites are found in fresh direct fecal smears
Small cysts can be found on centrifugal floataion with zinc sulfate as the flotation medium
What is the treatment for Giardia?
Dogs and ruminants
Albendazole for large animals
How much metronidazole would a 44 pound dog need if you are asked to dose it at 50 mg/kg QD x 5d to treat Giardia?
20, 000 mg
Are pet owners more commonly infected with Giardia than people who have no pets?
no epidemiologic relationship between pet owners and human infection
Is there a vaccine for Giardia?
What flagellate causes venereal disease, abortion, and infertility in cattle?
How is tritrichomonas fetus diagnosed?
see organisms on cytology from vagina/prepuce
serology of bulls
culture of preputial flush
What organism causes canker in birds?
How is avian trichomonas diagnosed?
DQ stained smear of lesion
What is the reservoir of Balantidium coli?
Association with what species increases the risk of Balantidium infection in humans?
Which protozoan we discussed has the largest cyst form?
What is commensal?
living with, on, or in another, without injury to either
Are most species of amoeba harmful?
no, most are non-pathogenic
What type of test will give you the best chance of finding intestinal protozoan trophozoites?
fresh direct fecal smears
What type of test will give you the best chance of finding Giardia cysts?
What is the definitive host of Toxoplasma gondii? Where does it live in the definitive host?
jejunum and ileum
What is the intermediate host of Toxoplasma gondii? How is the intermediate host affected?
amphibians, fish, reptiles, birds, and all species of mammals
lymph nodes, heart, skeletal muscle, brain
How can the intermediate host become infected with Toxoplasma gondii?
ingestion of bradyzoites in meat
ingestion of oocyts
How is the definitive host infected with Toxoplasma gondii?
cats ingests tissue cysts containing bradyzoites (usually by eating mice)
What are the three life forms of Toxoplasma gondii?
tissue cyst containing bradyzoites
How big are toxoplasma oocysts?
10 - 12 microns (small)
What happens after a cat eats an infected mouse? Describe the life-form changes.
cat ingests bradyzoites from mice
bradyzoites "hatch"(turn into tachyzoites) and penetrate the epithelial cells of the small intestines
cat sheds unsporulated oocysts
Are Toxoplasma oocysts infective immediately upon being released into the environment?
no...it takes 1 - 3 days in the environment for the oocysts to become infective
Is Toxoplasma considered a dange in immunocompetent individuals? What happens to the organism in an immunocompetent intermediate host?
there are no clinical signs
What three organ systems are most commonly affected in the cat?
Are cats showing signs of disease caused by toxoplasmosis usually shedding oocysts?
Is there a Toxoplasma antigen test?
How long will a positive antibody titer (concentration) for Toxoplasma last in the cat? What precent of healthy cats are seropositive?
positive titers last for years
this does not mean the cat is shedding oocysts (not shedding = no danger to humans)
Does a positive test mean a cat is infected with Toxoplasma?
no, it just means at some point in its life it ingested the infection
Can a healthy cat test positive for Toxoplasma?
List all the preventative measures pregnant women should take to avoid contracting toxoplasmosis.
avoid litter boxes
if they can't avoid litter boxes
: wear gloves while scooping litter, clean litter box daily before oocysts can sporulate and become infective
meat should be cooked well
wash hands after handling raw meat
wash fruits and vegetables well
wear gloves while gardening
cover outdoor sand boxes
What organism that causes abortion in ruminants was until recently believed to be Toxoplasma?
What are the three forms of Neospora caninum?
Who is the definitive host for Neospora caninum?
Can Neospora caninum be spread vertically (from mother to baby)?
yes...can cross placenta and infect fetus
What is the intermediate host of Isospora? Eimeria?
there is no intermediate host
In general, are protozoan oocysts resistant in the environment? Are they infective immediately upon entering the environment?
no and no
What is the genus name of the parasite you have probably seen in fecals from puppies or kittens? Is it zoonotic?
Why do you sometimes see blood in feces from puppies or kittens infected with isospora?
because they reproduce in intestinal cells which causes diarrhea, blood, and or mucus
Is the life cycle of Isospora direct or indirect?
What is the prepatent period of Isospora felis or canis?
Why would a veterinarian choose not to treat Isospora infection in a healthy, asymptomatic animal?
because this type of animal typically has an immune system strong enough to take care of it itself...they develop an immunity over time
How is it that Cryptosporidium can enter municipal water supplies?
because occysts are found in about 65-97% of surface water (lakes, ponds, swimming pools, etc)
How is Cryptosporidium diagnosed?
small oocysts found on fecal float
ELISA test for antigen
What does Crytosporidium cause?
Is there an intermediate host for Cryptosporidium?
Is Cryptosporidium zoonotic?
What species commonly carry Cryptosporidium?
calves under 4 weeks of age
Describe what happens in "autoinfection" and why parasites that can undergo this phenomenon can be so dangerous.
autoinfection is the ability of a parasite to re-infect a host without ever passing out of the host.
this is dangerous because it can cause an overwhelming infection
Of the ones we've discussed, which parasitic protozoan oocysts are the smallest?
Is there an epidemiological relationship between being in the veterinary profession and contracting Cryptosporidium?
yes...rates of infection are higher in the veterinary profession
What is the causative organism of EPM?
What is the definitive host of sarcocystis?
What kind of host is the horse for EPM?
What species serve as intermediate host for EPM?
How do horses become infected with EPM?
the sporocysts are ingested in opossum feces. they get into the GI tract and then the blood and then the CNS
What species spreads EPM through its feces?
How is it best to diagnose EPM in horses?
antibodies in CSF (blood tests only indicate exposure)
What kind of pollen has the "Mickey Mouse ears"?
What types of protozoa will we be studying?
What are the different types of flagellates?
What does the trophozoite of giardia look like?
two nuclei "eyes"
8 flagella (4 pairs)
What type of reproduction does giardia have?
Describe cyst ingestion of giardia.
trophozoites divide by longitudinal fission (asexual reproduction)
they proliferate in the small intestines
trophozoites are then passed in diarrhea but are incapable of causing infection and soon die
Where do cysts for giardia attach in the small intestines? What does it do there?
brush border of small intestines
What do the "suckers" of the giardia cysts do to the small intestines and what does this cause?
damage villi where they attach
causes secretory diarrhea
Which is the most common intestinal parasite in people in North America?
What species does Balantidium coli infect?
primates including humans
What kind of life cycle do Balantidium coli have?
Where do Balantidium coli infect?
the large intestines
What are the symptoms of Balantidium?
can cause diarrhea, abdominal pain, can be severe in debilitated humans
How do animals get entamoeba histolytica?
humans spread to pets
What are the symptoms of entamoeba histolytica
What are the different coccidians?
isospora and wimeria
How are coccidians spread?
How do you diagnose coccidians?
on float or direct smear
may be hard to find so seological tests exists
passed in feces
in tissue cysts
What are the different life forms of toxoplasma in cats and what do they do?
oocyst (shed in feces)
tachyzoites (detrimental, motile form)
bradyzoites (resting form in tissue cysts)
Which organ system in cats becomes infected with toxoplasma?
any of them
Are seropositive cats a risk to humans?
Describe the life cycle in the intermediate host for toxoplasma.
tachyzoites form and invade and multiply in any tissue. they for tissue cysts containing bradyzoites in muscle, organs and CNS
What can toxoplasma cause in human babies?
If a pregnant woman has a positive titer test for toxoplasma, what does that mean?
she is protected
What are the clinical signs of Neospora caninum?
neurological (ataxia, stiffness, circling, ascending paralysis, and rigid hyperextension of hind limbs)
Who is most commonly infected with Neospora caninum?
puppies 5 - 6 weeks old
What is the treatment for Neospora?
How is Neospora diagnosed?
serology in large animals
How do you prevent Neospora?
avoid feeding dogs raw meat diets
What are the different intestinal coccidia?
What kind of life cycle does isospora and eimeria have?
direct life cycle (no intermediate host)
When do isospora sporulate?
1 - 2 days (eimeria takes longer)
How do animals get isospora or eimeria?
host eats infective oocyst
sporozoites hatch and enter intestinal cells
What animals get eimeria?
not found in dogs or cats
What is the treatment for isospora and who do we treat?
sulfonamides and environmental control (strong ammonium hydroxide...resistant to most disinfectants)
Where do cryptosporidium live in hosts?
What is the treatment for cryptosporidium?
Cryptosporidium can be fatal for what kind of people?
How do people typically get cryptosporidium?
public water sources
What kind of life cycle does sarcocystis have?
predator-prey life cycle
Define the predator-prey life cycle.
sporocysts passed from definitive host
sarcocysts live in muscles of intermediate host (prey species)
birds/insects transport hosts
What does sarcocystis cause in rottweilers?
What are the clinical signs of EPM?
What does EPM stand for?
equine protozoal myeloencephalitis
What is the treatment for EPM?
Marquis antiprotozoal paste