VETS 385: Final Exam

parasite

organism that lives on or within another organism of a different species and becomes dependent on them

host

organism which harbors the parasite (food and shelter)

symbiosis

association between at least two living organisms of different species

predator-prey

one benefits at others expense, prey is food for predator

mutualism

both organisms benefit

parasitism

one benefits (parasite), other is harmed (host)

phoresis

two organisms travel together, neither helped nor harmed

commensalism

one benefits, other is neither harmed nor helped (feeds of the waste)

prepatent period

time between when the host gets infected with the parasite and when the infection can be detected diagnostically

definitive host

sexual reproduction occurs, adult stage parasite

intermediate host

asexual reproduction occurs, larval stage parasite

parastenic host

larval parasite lives without further development

reservoir host

carries parasite but is not suffering from disease, can be passed to other hosts

anthelmintics

targets parasitic worms

acaricides

targets ticks and mites (dips, sprays, topical)

insecticides

targets insects

antiprotozoals

treat infections caused by protozoa

obligatory parasite

only survives in hosts

facultative parasite

can live with or without host

periodic parasite

not necessary, only visit intermittently for intervals often to feed

monoxenous / homoxenous

infects only one type of host

stenoxenous

narrow host range

euryxenous

broad host range

aberrant

wonders from usual site into an organ or location where it does not ordinarily live

incidental

found in animal other than the natural host

systems of nematodes

complete digestive system, no respiratory or circulatory system

oviparous

female lays eggs that contain morula stage within eggshell (cluster of cells)

ovoviviparous

female lays eggs that hatch internally or within the eggshell

larviparous / viviparous

female directly gives birth to fully developed larvae, no egg stage

ascaroid egg type

oviparous, spherical, pigmented center, morula

trichostrongyle egg type

oviparous, elongated, both ends pointed, colorless, morula

trichinelloid egg type

oviparous, elongated, prominent bipolar plugs at ends, plugs are colorless

spiruroid egg type

ovoviviparous, smooth outer wall, many have operculum

infective larval stage

stage 3

lung migration pathway

1. L3 egg is ingested

2. grows and migrates to GI

3. penetrates GI lining and enters bloodstream

4. migrates to liver --> right side of heart --> lungs

5. coughed up and swallowed again

6. back in the GI where they grow to L5 stage

7. reproduce and L1 stages are defecated out of body

somatic migration

1. infective larvae migrate to GI and move into bloodstream

2. travel to somatic sites throughout body (muscles, liver, heart, lungs, brain, eyes, mammary glands)

3. some form protective capsule to hide

4. reactivate when immune system is weakened (pregnancy)

zoonotic nematodes

toxocara, baylisascaris, ancylostoma

roundworms

toxocara, toxoascaris, parascaris, ascaris, ascaridia, paraspidodera, baylisascaris, trichinella

toxocara

toxocara common name

round worm

toxocara damage

pot-belly, vomiting worms, diarrhea with worms

parascaris

parascaris common name

equine roundworm

ascaris

ascaris common name

swine roundworm

ascaris damage

milk spots on liver

ascaridia

ascaridia common name

poultry roundworm

paraspidodera

paraspidodera common name

guinea pig roundworm

baylisascaris

baylisascaris common name

raccoon roundworm

nematodes with ascaroid egg type

all roundworms

ancylostoma / uncinara

ancylostoma / uncinara common name

hookworm

damage of ancylostoma

severe blood loss, bloody stool --> dark tarry stool, creeping eruptions in humans!

trichostrongylus

trichostrongylus common name

hairworm

which nematode causes dingle berries

trichostrongylus

ostertagia

ostertagia common name

stomach worm

haemonchus

haemonchus common name

barber pole worm

oesophagostomum

oesophagostomum common name

nodular worm

nematodirus

nematodirus common name

thread-necked worm

dictyocaulus

dictylocaulus common name

lungworm

stephanurus

stephanrus common name

kidney worm

nematodes with trichostrongyle type egg

ancylostoma / uncinaria, trichostrongylus, ostertagia, haemonchis, nematodirus, dictyocaulus, stephanurus

strongylus

strongylus common name

large strongyles of horse

cyathostomins

cyathostomins common name

small strongyles of horse

parelaphostrongylus

parelaphostrongylus common name

brain worm

nematodes with strongyle egg type

strongylus, cyathostomins, parelaphostrongylus

trichuris

trichuris common name

whipworm

eucoleus

eucoleus common name

lungworm

dioctophyme

dioctophyme common name

giant kidney worm

perasonema

pearsonema common name

bladder worm

nematodes with trichinelloid egg type

trichuris, eucoleus, dioctophyme

trichinella

larva in muscle

trichinella common name

roundworm

eggs of trichinella

larviparous = no eggs

strongyloides

strongyloides common name

intestinal threadworm

eggs of strongyloides

ovoviviparous = hatch before leaving host

oxyuris

oxyuris common name

equine pinworm

habronema

habronema common name

stomach worm of horse

IH of habronema

stable fly

nematodes with spiruroid egg type

strongyloides, oxyuris, habronema