1 - Introduction Flashcards
What are the impact of parasites on the host animal
Compete for nutrition
mechanical obstruction
Suck or consume bodily fluids
Pressure atropy
Allergic reactions
Produce toxic substances
carry pathogens including other parasites
Injury on entry and or migration
How do parasites impact the host animal by competing for nutrition?
By ingesting intestinal contents - ascarids (roundworms)
By absorbing them thru body walls - tapeworms
How do parasites impact the host animal by mechanical obstruction?
of the intestines - ascarids
Of the bile ducts - ascarids, trematodes
Of the blood vessels - canine heartworm
of the bronchi or trachea - lung worms
of the lymph channels - filarial nematodes
How do parasites impact the host animal by sucking or consuming bodily bluids
Blood - mosquitoes, hookworm
Lymp - midges
Exudates - lungworms
Feed on or destroy solid tissues
Directly - giant kidney worms, liver flukes
After liquefying them - chiggers
How do parasites impact the host animal by pressure atropy
Hydatid cysts (echinococcus spp)
How do parasites impact the host animal by allergic reactions
Hypersensitivity, scar tissue (pig livers)
Black flies, mosquitoes, fleas
How do parasites impact the host animal by produce toxic stubstances
Hemolysins, histolysins (break down tissues), anticoagulants
How do parasites impact the host animal by carrying pathogens including other parasites
Mosquitoes - malaria, heartworm, WEE, WNV
Dog flukes - ‘salmon poisoning’
How do parasites impact the host animal by injury on entry and/or migration
Creeping eruption - cutaneous larval migrans
Sarcoptic mange
reduce host’s resistance to other dz’s and parasites
What is the vet techs job in parasitology?
dx and px, control and prevention, tx, public health, client ed
COMMUNICATION
What is the functional definition of parasitism?
A parasite is a smaller organism(typically) that lives within or on top of another, generally lger, organism, the host
The parasite will cause some degree of harm to the host. this “harm” ranges from mild-severe
The parasite absolutely requires the host to complete its life-cycle
What are the types of parasites?
Macroparasites - helminths, arthropod
Microparasites - protozoa, bact, fungi, viruses
What different types of helminths?
Worms!
Nematodes - roundworms, hookworms, pinworms, whipworms, etc toxocara canis - dog roundworm
Flat worms - cestodes, diphyllobothrium spp (tapeworm of fish-eating vertebrates), trematodes (flukes), fascioloides manga (giant liver flukes of ruminants
What are some examples of parasitic arthropods?
bugs, fleas, flies, lice, mites and ticks
What do tapeworms =
cestodes
What are different types of protozoa parasites?
amoeboids, ciliates, flagellates, sporozoans (apicomplexans (coccidia))
In regards to hosts for parasites, what does definitive host mean?
DH = definitive host
Required for ALL parasites (need hot to survive or reproduce)
Adult parasites are in the DH. Parasite undergoes sexual reproduction inside DH
sometimes asex in the DH
What is an intermediate host?
Required for MANY parasites (indirect life cycles)
Parasite undergoes development within IH
never sexual reproduction
What is a paratenic host?
PH - helpful but not required
Infectin occurs but no reproduction
no development
What is a transport host?
Helpful but not required
no infection. Simple transport (mechanical vector)
WHat is the shedstage and the infective stage?
Shed stage is what leaves the infected host (egg, larva, cyst)
Infective stage is what is infective to the next host - usually takes time in the environment for a shed stage to become in infective stage
Pre patent period (PPP) (infected but not shedding detectable #’s)
patent (infected and shedding detectable #’s of shed stages)
Prevalence (% infected in a population) and intensity (how many parasites in an infected animal
How does one aquire parasites?
ingestion of infective stages fron contaminated environment
Ingestion of infective stges in infected IH, often regular prey
Skin penetration
Inoculation of infective stages by infected arthropod vectors
transfer by direct contact w/ other infected hosts
trasnmammary infection of larvae from mother to offspring
Give an example of an infected horse with adult worms in the intestine spreading directly
Eggs pass in the feces -> larvae hatch from eggs -> horse ingests larvae while grazing and becomes infected -> larvae mature to adult worms, which produce to make worms
Give an example of an indirect parasite life cycle using a wolf
A wolf has a parasite-> shed thru feces-> parasite in grass->moose eats grass as IH-> ingests the egg and larvae migrate to target tissue -> wolf eats infected moose
