Internal Parasites Flashcards by Unknown Unknown

what parasites are classified as nematodes?

ascarids (roundworms), strongyles, hookworms, lungworms, whipworms, heartworms, capillaria

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what is the life cycle of a nematode?

eggs passed in feces
eggs mature into larval stages and become infective at L3
transmitted to direct host from environment, mom, or intermediate host
matures into adult in target organ
sexual reproduction= more eggs
eggs are passed in feces and cycle repeats

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what are some characteristics of ascarids?

hardy in environment
TO: small intestine
shell: thick, round, bumpy
inside: single embryo

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what are the two different roundworm migration life cycles?

tracheal migration and somatic migration

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what are the steps of the tracheal migration life cycle?

L3 penetrates intestinal wall into bloodstream
travels to liver and then lung alveoli
L3 are coughed up from trachea and swallowed, continuing cycle

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what is the somatic migration life cycle?

L3 travel to organs and tissue, worm becomes encysted in tissues

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toxocara canis

dog roundworm
ascarid

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toxocara cati

cat roundworm
ascarid

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ascaris suum

pig roundworm
ascarid

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what age is toxocara canis most common?

puppies because it is transplacental

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how is toxocara cati spread?

ingestion of ova or paratenic host

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how is ascaris suum spread?

varied pathogenicity

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what animals is toxascaris leonina seen in?

can be seen in dogs, cats, and wild carnivores

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what are some characteristics of baylisascaris procyonis?

DH: carnivores
mostly seen in raccoons
infection through fecal-oral or paratenic host
zoonotic

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what are some characteristics of parascaris equorum?

large roundworms in horses
foals mostly affected
tracheal migration
CS: respiratory signs, colic, diarrhea, intestinal obstruction

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what are some characteristics of dioctophyma renale

aka giant kidney worm
DH: fish-eating carnivores
IH: fish
seen in urine
infects through ingestion of raw fish

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what are some characteristics of heterakis?

aka cecal worm
DH: poultry
IH: earthworms
100% mortality in turkeys

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what are some characteristics of hookworms?

can infect dogs, cats, cattle
adults are blood suckers
TO: small intestine
outside: thin shell, oval
inside: grape clusters

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ancylostoma caninum

canine hookworm
transdermal infection most common

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ancylostoma tubaeformae

feline hookworm

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uncinaria stenocephala

hookworm
fecal-oral most common transmission
less pathogenic than ancylostoma

what are some characteristics of strondyloides?

aka threadworm
infects nearly all species
GI tract parasite: causes severe diarrhea and emaciation
ova in feces are embryonated

S. westeri

threadworm in foals (strodyloide)

what are some characteristics of strongyles (strongylus valgaris)

aka blood worm
DH: horses and ruminants/ swine
TO: cecum and colon
major source of colic
blood suckers, cause ulcers
subclinical in adults, diarrhea and colic in foals

oesophagostomum

aka nodular worm falls under strongyles category infects cattle, sheep, goat, swine, and ruminants TO: small intestine

syngamus trachea

aka gape worm falls under strongyles category infects birds (chicken/ turkey and wild birds) TO: trachea CS: gaping due to respiratory distress

parasitic gastroenteritis (PGE)

caused by stronglyes: trichostrongylus infects herbivores (domestic cattle, goats and sheep, wildlife, exotic) CS: cattle wasting

trichostrongylus

aka hairworm strongyle: parasitic gastroenteritis

cooperia

aka bankrupt worm strongyle

ostertagia

aka stomach worm strongyle

what are some characteristics of haemonchus contortus?

aka barber-pole worm strongyle blood sucker infects ruminants (can be part of PGE) antihelmintic resistance CS: failure to thrive, weight loss, bottle jaw

what are the different types of metastrongylids (lungworms)?

metastrongylus, filaroides, aelurostrongylus

what are some characteristics of metastrongylus?

metastrongylid DH: swine IH: earthworm CS: barking cough causes growth retardation

what are some characteristics of filaroides?

metastrongylid DH: dog seen in feces or sputum (mixture of mucus and saliva coughed up)

what are some characteristics of aelurostrongylus?

metastrongylid DH: cat IH: snails and slugs CS: coughing, increased RR, weight loss larva coughed, swallowed, and passed in feces paratenic hosts: birds, frogs, lizards, mice

what are some characteristics of spirurids?

aka stomach worms (physalopetera rara) DH: wild carnivores IH: insects, reptiles paratenic hosts: reptiles, amphibians, mammals CS: vomiting use fecal direct smear method to test

what are some characteristics of onchocerca?

aka skin nodular worm fly vector TO: SQ tissue, conjunctiva, peripheral blood vessels CS: dermatitis

what are some characteristics of trichuris?

aka whipworms lemon shaped and have bipolar plugs TO: cecum, large intestine CS: anemia, weakness, diarrhea

T. vulpis

trichuris (whipworm) seen in dogs, ruminants, and rare in cats

T. suis

trichuris (whipworm) seen in swine

what are some characteristics of capillaria?

aka threadworm DH: wild mammals, canine, feline, avian TO: small intestine ova are resistant have asymmetrical bipolar plugs

how can C. vulpis be tested?

C. vulpis: type of capillaria tested through fecal float since diarrhea is a symptom

how can C. plica be tested?

C. plica: type of capillaria tested through eggs in dog or cat urine CS: pollakuria, straining, urinary accidents

what are some characteristics of pinworms oxyurids?

oval, operculated ova, thin shell, asymmetrical plugs

oxyuris equi characteristics

pinworm DH: horses TO: cecum and colon eggs attach to perineal hairs, itchy scotch tape derm test used and can rarely show up on fecal floats

what other species can pinworms infect besides horses?

rodents and reptiles (common, often nonpathogenic, may be commensal)

what are some characteristics of dirofiluria immitus?

aka heartworm DH: carnivores IH: mosquito TO: right ventricle of heart and pulmonary artery adults produce microfilaria

what is the life cycle of heartworm?

1. mosquito feeds on infected animal and ingests microfilaria 2. microfilaria matures in mosquito to L3 stage 3. mosquito feeds again and L3 infective larvae goes into uninfected animal's blood 4. larvae mature to L4 and migrate to heart and lungs 5. worms reproduce and make more microfilaria

what are the different ways to test for heartworm?

antigen test: tests for female worms only direct: drop of blood on slide, can see microfilaria hematocrit tube: can see microfilaria above buffy coat

how do you performed a modified Knott's test?

heartworm test 1. mix 1 mL anticoagulated blood with 10 mL of 2% formalin 2. centrifuge 3. pour off most of supernatant 4. add 4-7 drops of NMB stain 5. look for microfilaria