Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Parasitology > Nematodes > Flashcards

Nematodes Flashcards

0
Q

general life cycle of nematodes

A
  • egg/larvae : L1 - L5; L3 is infective stage!
  • larvae in IH
  • adults in DH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

all nematodes general characteristics

A

tubular bodies with body cavity

  • dioecious
  • cuticle modifications - cervical alae
  • males may have a copulatory bursa and/or spicules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

3 different types of eggs

A

oviparous - single stage or murula

ovoviviparous: single L1 larva
larviparous: eggs retained in uterus - “gives birth” to live larvae/microfilariae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how to diagnose nematodes

A
  • McMaster’s procedure: fecal, egg count, not sensitive
  • fecal culture: mature larvae to L3
  • fecal sedimentation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

blood diagnostics for nematodes

A
  • microfilariae
  • blood smear
  • difil filter technique
  • modified knott’s concentration test
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

trichostrongyle : characteristics

A

superfamily of nematodes

  • small, bursate, usually in ruminants
  • inhabit abomasum and SI
  • all their eggs look the same
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

the HOTC trichostrongyle

A

H - Haemonchus = barberpole worm = small lacet tooth at base
O - Ostertagia = brown stomach worm = small mouth
T - Trichostrongylus = hair worm = no mouth
C - Cooperia = cooper’s worm = head has swollen bulbous appearance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

life cycle of trichostrongyle

A
  1. eggs shed in feces
  2. L1 - L3 in feces - feed on bacteria
  3. L3 ingested while DH grazing - exsheath in rumen
  4. enter wall of abomasum or SI - develop to L4. lumen dwelling adult in mucosa of predilection site
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

hypobiosis

A

larval inhibition - nematodes have ability to arrest development and go dormant at L4 stage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

paraasitic gastroenteritis (PGE)

A
  • caused by a compex of mainly trichostrongyloid nematodes
  • major impediment in cattle
    clinical signs: diarrhea, anemia, “bottle jaw”
    weanlings most susceptible
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Ostertagia ostertagi - “brown stomach worm” pathogenesis

A
  • larvae destroy gastric glands as they develop

- damages Hcl producing parietal cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

ancyclostoma caninum

A
  • hookworms w/ deep buccal teeth, curved anterior end
  • found in dogs and cats
  • habitat = SI
  • life cycle is direct
  • egg characteristics: 8-cell morula
  • dx: float
  • disease: young animals, anemia, diarrhea, zoonotic!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

toxocara canis

A
  • roundworms: large worms, lateral anterior alae
  • found in all mammals
  • SI, lungs, liver,
  • life cycle = direct
  • float
  • found in young animals, diarrhea, coughing, pot belly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Trichinella spiralis

A

trichina worm, small and slender

  • found in mammals
  • uses IH and DH via consumption
  • adults = SI, larvae = striated muscle
  • life cycle indirect
  • eggs hatch in utero, birth to live larvae
  • dx: serum, muscle biopsy
  • zoonotic, severe disease in humans
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

dirofilaria immitus

A

heartworm, long slender, white, tapered anteiror ends

  • cats, dogs, ferrets
  • IH = mosquitoes
  • found in pulmonary artery, right ventrical, circulating blood
  • life cycle = indirect
  • egg characteristics = live larvae
  • dx = microfilara in blood, antigen test, radiographs
  • disease = heart failure, pulmonary disease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

life cycle of dirofilaria immitis

A
  1. Mff released by female worm - enters circulation, mosquito fees on dog with circulating Mff
  2. Mff develop to infective larvae L3
  3. infective larvae are deposited at the skin surface when mosquito takes another blood meal - L3s enter DH @ mosquito bite wound
  4. larvae undergo several molts during their migration to the heart and lungs
  5. adult worms mature in the heart or lungs, mate and produce Mff
16
Q

diagnosing heartworm

A
  • detection of antigen uses point of care tests like SNAP, dirochek, snap 4DX, etc.
  • detection of circulating microfilariae
  • imaging techniques
17
Q

when dogs become antigen positive for dirofilaria immitis

A
  • with no prophylaxis the earlies is 5m with the usual being 7 months
  • with macrocyclic lactone with doses mixed its usually 9 months
18
Q

when dogs become Microfilariae positive for dirofilaria immitis

A
  • the earliest with no prophylaxis is 6.5months

- with missed macrocyclic lactone doses they may never develop mff or they may appear transiently in small numbers

19
Q

what is the most sensitive test for dirofilaria immitis

A

dirocheck (uses serum or plasma)

20
Q

what do the Ab tests for dirofilaria immitis tell you?

A

they tell you if the dog WAS an infection. so if the animal had L3s n the system and the monthly preventative killed them off, the AB test will still come up positive. so it will tell you if you were positive at any point.

21
Q

if a dog is Ag: positive and Mff: negative what could cause this?

A
  • maturing infection; Mff not yet in circulation
  • use of preventative without removing adult worms
  • use of microfilaricide w/o removal of adult worms
  • unisex (female) infection; males not present
  • dog is a true immune -mediated occult
  • failure to use microfilaria concentration test
22
Q

if a dog is Ag: negative but Mff: positive what could cause this?

A
  • Mff are those of another species
  • Mff were acquired transplacentally
  • adult worms were removed or have died but Mff persist
  • contamination of test materials from previous sample
23
Q

If a dog was Ag: variable and Mff: positive OR negative

A
  • fluctuating Ag level due to number of female worms, ages of worms or quality of sample
24
Q

pathogenicity/clinical signs of dirofilaria immitis

A
  • disease primarily due to adults - right ventricle, pulmonary artery
  • irritate vessel walls, produce pro-inflammatory molecules that induce inflammation of vessels: “villous endarteritis”
  • vascular resistance - vessel inflammation increases cardiac workload
  • decreased cardiac output - decreased organ perfusion, decreased circulation, exercise intolerance
  • coughing and hemoptysis (blood in sputum)
  • vena cava syndrome: infect atrium and vena cava, overrun with worms, obstruct blood flow, interfere with tricuspid valve closure, liver congestion, herat murmur
25
Q

canine v. feline heartworm

A

canine: highly susceptible, many worms, worms long lived, usually Microfilaremic, heart and lungs affected, easily diagnosed, treatment and preventatives available
feline: less susceptible, few worms, few worms cause disease, worms short lived, usually amicrofilaremic, lungs most affected, diagnoses difficult, only symptomatic tx available, preventatives available

26
Q

tx of heartworm:

A
  • melarsomine dihydrochloride (immiticide)
  • greater efficacy of killing adult worms
  • NO activity against worms < 4months
  • convenience of administration
27
Q

alternatives to immiticide: “slow kill”

A
  • continuous monthly use of preventatives
  • currently macrocyclic lactones are NOT APPROVED for this use
  • requires compliant monthly treatment
  • may require long periods to remove all worms
  • view this as a viable alternative when immiticide cannot be used
28
Q

treatment/control of dirofilaria immitis

A
  • treat clinical signs
  • surgical removal of worms
  • removal of Mff
  • year round monthly preventative
  • annual testing

Parasitology (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions