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Define symbiosis.
organisms living together
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Define mutualism.
- symbiosis that is mutually beneficial
- no disadvantage to either party
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Define commensalism.
one party draws benefit from relationship but neither party is harmed
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Define parasitism.
one party draws benefit (parasite) and the other is harmed (host)
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Define infestation.
parasite in/on animal
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What is the difference between a facultative and an obligate parasite?
- facultative parasite: may or may not be parasitic
- obligate parasite: always parasitic (can only exist as a parasite)
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What is a patent infection?
reproducing adults (female reproducing eggs)
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Define prepatent period.
time from parasite entry until reproduction occurs
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Define incubation period.
time from infection to disease
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What's the difference between the prepatent period and the incubation period?
prepatent is before infection and incubation is from infection to time of disease
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To be successful, a parasite must do what?
- gain entry to host
- avoid destruction and avoid destroying the host
- reproduce
- progeny gain entry to next host
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List 5 ways a parasite can gain entry to a host.
- ingestion
- skin penetration
- inoculated by vector
- transplacental
- transmammary
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How do parasites cause disease?
- cellular or tissue destruction
- interfere with blood supply
- mechanical obstruction
- competition for nutrients
- irritation to the host
- competition for nutrients
- irritation to the host
- transmission of disease
- host hypersensitivities
- ingestion of host's blood
- secondary infections
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Define ectoparasite.
- external parasites
- live on the host
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Define endoparasite.
- internal parasites
- live in the host
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What is helminthe?
flatworms and roundworms
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Define definitive host.
host in which the parasite reaches reproductive stage
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Define intermediate host.
- some parasites require a host for part of the life cycle
- for development of intermediate/larval stages
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What's the difference between biological and mechanical vectors?
- biological vector: parasite uses vector for life cycle changes
- mechanical vector: no life cycle changes go on and the vector is just used to transport the parasite
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What is paratenic (transport) host?
- carries immature parasite
- no development occurs
- host may spread it over distances
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What is an incidental or aberrant host?
unnatural, may/may not be hurt
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What is meant by the term "reservoir"?
wildlife hosts that make eradication and control difficult
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What's the difference between direct and indirect life cycles?
- direct: parasite needs only one host
- indirect: intermediate host required (requires more than one host)
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What are different ways to test for the presence of parasites?
- fecal exam
- gross exam
- microscopic exam
- direct smear
- concentration methods (flotation and sedimentation)
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The gross fecal exam includes description of what things?
- consistency
- color
- presence of blood
- presence of mucus
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What is the difference between hematochezia and melena?
- they are different types of blood present in feces
- hematochezia: red and from colon
- melena: black, tarry and from upper GI tract
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Where does mucus in stool come from?
colon
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How do you perform a direct smear?
- mix small amount feces with saline
- look for protozoa, larvae, and ova
- stain smear
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How do you perfom a passive floatation?
- mix feces and solution in cup, test tube, kit container
- pour through strainer
- add floatation solution to just over top (meniscus)
- place cover slip on top
- wait
- examine
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How do you perform a centrifugal sedimentation?
- mix feces with water (filters out debris)
- centrifuge for 3 - 5 minutes
- slowly pour off supernatant
- pipette from top of sediment
- place on slide
- add cover slip
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How do you use a Baermann Apparatus?
- wrap feces in gauze
- hold gauze in water with stick
- keep in water for several days
- the larvae will sink
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How do you perform a centrifugal and floatation
- mix feces and solution in a cup, test tube, or kit container
- pour thru screen into test tube
- centrifuge for 3 - 5 minutes at 1500 rpms
- fill to top with more floatation solution
- lay cover slip over top of tube
- examine in 10 minutes - the ova will have floated to the cover slip
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What is the time requirement for floating in saturated sugar solution?
20 - 30 minutes
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What is the time requirement for floating in zinc sulfate solution?
10 - 15 minutes
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What is the time requirement for floating in sodium nitrate solution?
10 - 15 minutes
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What are the advantages to using saturated sugar solution?
- inexpensive
- readily available ingredients
- doesn't distort worm ova
- long shelf life
- doe not crystalize
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What are the disadvantages to using saturated sugar solution?
- sticky and messy
- ova rise slowly (20 - 30 minutes)
- may get a false negative
- may distort larvae and cysts
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What are the advantages to using zinc sulfate?
- commerically available
- floats protozoan cysts without distortion
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What are the disadvantages to using zinc sulfate?
- expensive
- may distort helminth ova
- some use magnesium sulfate
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What are the advantages to using sodium nitrate?
- efficient at floating ova
- may even float fluke eggs
- commerically available
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What are the disadvantages to using sodium nitrate?
- expensive to buy
- forms crystals and air bubbles
- distorts ova if it sits more than 20 minutes
- floats more fecal debris
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What specific gravity should floatation solutions be between? Why?
- 1.200 - 1.300
- will make eggs float and debris/poop sink
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How should your light be when examining unstained fecals?
low light
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Why hsould you drop your condenser down when examining fecals?
because it's a liquidq
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What power(s) should you use?
low power
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Which technique works best for finding larvae?
baermann apparatus
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What is the McMaster technique used for?
- for a quantitative fecal exam, mainly used for large animals to see if there are enough eggs to see if they are worth medicating
- weigh out feces
- add solution
- centrifuge
- add to chamber
- count
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Who are at most risk for parasitic zoonoses?
- immunocompromised
- pregnant
- kids
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What can you do besides using drugs to decrease transmission of parasites?
- get rid of feces
- prevent access to urine
- destroy ova/larvae
- human sanitation (wear gloves)
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What are the different types of symbiosis?
- mutualism
- commensalism
- parasitism
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_____ symbiotic relationships are parasitic.
few
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Most symbiotic relationships are what?
- mutualistic
- commensalistic
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What is an incidental parasite?
parasite in the wrong host (aberrant host)
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What are the two types of vectors?
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What is a fomite?
inanimate object transferring a parasite
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What is the order of classification?
- kingdom
- phylum
- class
- order
- family
- genus
- species
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For a scientific name, what is capitalized and what is not capitalized?
- genus: capitalized
- species: not capitalized
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What is a scientific name made up of?
genus and species
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What is the silly memory trick for remembering the order of classification?
kings play chess or fight green snakes
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What is another name for transplacental migration?
intrauterine transmission
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What is transplacental migration?
- larvae within the circulation leave blood and become dormant in muscles and organs until host becomes pregnant
- in late pregnancy larvae leave tissues, cross placenta and enter fetal tissues
- the neonate born with larvae
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What is transmammary infection?
- arrested development until become pregnant
- larvae enter mammary glands of host
- larvae is then secreted in the milk
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What are trematodes?
flukes
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What are cestodes?
tapeworms
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What are protozoa?
single celled organisms
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What are nematodes?
round worms
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What are acanthocephalans?
thorny - headed worms
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Are acanthocephalans common in dogs and cats?
no, they are rare
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What are arthropods?
- hard, segmented bodies
- insects and arachnids
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What are the different types of hosts?
- definitive
- intermediate
- transport (paratenic)
- aberrant (accidental)
- reservoir
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What is a life cycle?
how parasite develops and reproduces
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What are the different ways to diagnose parasites?
- observe adult parasite
- observe immature form (larva, egg)
- serological tests for antibodies
- clinical signs from patient
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Why do we do fecal exams?
to diagnose the source of GI disease
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What are some sources of GI disease that we can see in a fecal exam?
- parasites
- hemorrhage in GI tract
- pancreatic insufficiency
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What are the different types of fecal consistency we see in a gross exam?
- watery
- soft
- cow-pie
- well-formed
- hard
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Does the age of the poop affect the results of a fecal exam?
yes
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What types of parasites do we see in a gross exam?
- proglottids
- maggots
- bots
- roundworms
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What are proglottids?
tape worm segments
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Does ova float in water?
no
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What type of floatation solutions do we use?
- saturated sugar
- saturated salt
- sodium nitrate
- zinc sulfate
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What are kits?
what you send home with clients to collect a fecal sample
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What are different types of disposable kit?
- ovassay
- fecalyzer
- ovatector
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Where does the centrifugal sedimentation concentrat ova?
at the bottom
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When do we use centrifugal sedimentation?
use for heavy ova (flukes)
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What part of the slide do we examine during a microscopic examination?
the entire slide
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Will we ever need to go to high dry in microscopic examination?
yes
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What is a quantitative fecal exam?
find the number of eggs per gram feces
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What types of serological tests do we use?
- IFA
- ELISA
- agglutination
- western blot
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What do serological test look for?
antibodies
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What do we need to do for client education?
explain treatments and why and when re-treatments may be needed and how the patient can be re-infected
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What is treatment based on?
parasite lifecycle
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How do we prevent parasites?
- need to know life cycle (how it spreads, presistence in environment, reservoir hosts, intermediate hosts)
- drug therapies used for prevention
- sanitation techniques
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How do we control the intermediate host?
- limit access to them
- avoid uncooked/undercooked meat
- remove other host (fleas, ticks, etc)
- monthly preventative drugs
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When do we deworm cows?
early spring, 4 weeks, 8 weeks
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When do we deworm horses?
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When do we deworm pups/kittens?
every 2 weeks beginning at 2 weeks of age
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What are the two ways the CDC say we need to do for treatment and prevention of parasites for dogs and cats?
- deworm at 2, 4, 6, 8 weeks of age and then every 3 months until 1 year of age
- deworm at 2, 4, 6, 8 weeks of age then begin monthly heartworm preventative year-round
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What kind of periodic testing do we need to do for prevention?
fecal analysis & blood work
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