Brainscape's Knowledge GenomeTM

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


See full index

Parasitology > Spiruroids - Heartworm > Flashcards

Spiruroids - Heartworm Flashcards

1
Q

Lifecycle of Canine Heartworm

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

Pathogenesis of heartworm

A

Presence of worm and Wolbachia (bacteria needed for survival) -> proliferative endarteritis (thickening) of pulmonary ateries -> decreased compliance ++

Thrombosis and thromboembolism (esp with dead parasites) -> pulmonary hypertension -> increased afterload of R ventricle -> R ventricular hypertrophy and dilation -> RSCHF +/- caval syndrome (worms migration to the heart and liver in the end stages)

Clinical signs caused by the immune response. Antigens also from Wolbachia

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

Pulmonary Arterial Disease?

A

Myointimal proliferation > villus proliferation of endothelium; inflammation; leakage

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

Caval Syndrome

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

Clinical signs

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Heartworm diagnosis

A
  • History - travelled recently? Heartworm prevention?
  • Detection of mff in blood (won’t tell you which species)
  • concentration methods (knotts test, filtration method)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is an occult infection?

A
  • 30% are occult
  • no mff in the circulation

(all worms are the same sex, single worm infection, pre-patent infection or geriatric worms, ectopic infections, drug induced elimination (ivermectin, doxycycline), immunologically mediated elimination of mff)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Problems with diagnosis methods?

A

False neg due to occult infection

No indication of worm burden

Other filarial species in your area???

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

Further tests

A
  • Antigen tests to adult female worms (at leats 3 females needed for consistent results)
  • SNAP ELISA
  • Sp (96-100%) and Se (90-96%)
  • Beware - PPV and NPV when interpreting test in low prevalence area.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does the inverted D mean?

A

enlarged R ventricle

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

Control of heart worm.

Drug efficacy on the age of parasite

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Treament step 1: supportive care

A

A) strict rest up to 4 weeks post treatment (exercise makes RSCHF worse)

B) corticosteroids: prednisalone 0.5 mg/kg alternate days pre- and up to 1 month post adulticide

C) PLUS doxycycline @ 10 mg/kg for 3-4 weeks (Wolbachia)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Treatment Step 2: Prevent new infections and kill mff

A

Macrocytic lactones (monthly chew or injectible) start on day 0

  • prevent new infection
  • Kills circulating mff over 7-10 days old (beaware of anaphylaxis if too quick)
  • over the longer term (4-12 month) kills juveniles and adults
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Treatment Step 3: Kill Adults

A

Adulticide:

  • Melarsomine by deep IM lumbar injection - kills worms >4mo
  • (one injection followed at least by 1 month later by 2 injections of the same dose 24 hours apart)
  • Monitor clinical improvement
  • repeat antigen test in 6 months to confirm adulticide success.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Overall treatment timeline

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How to deal with caval syndrome?

A
  • surgical extraction of worms
17
Q

Alternative regime “soft kill”

A
  • if don’t have melarsomine use ML + doxycycline (10mg/kg, 1 month on, 2 months off) over 9 months-12 months to kill adult worms.
18
Q

Problems with soft kill method?

A

Clinical signs may develop or worsen in the interim

Dont know when adults are dying

resistance?

19
Q

Heartworm in cats prevalence

A

5-20% of that in dogs

20
Q

Features of heartworm in cats

A
  • most worms don’t mature
  • 8 month PPP
  • often no mff
  • shortened adult survival (2-3 years)

Aberrant migration (e.g. CNS)

21
Q

Clinical signs of heartworm in cats

A

HARD

Heartworm Associated Respiratory Disease

  • due to larvae arriving
  • pulmonary arteriole hypertrophy, pulmonary oedema, tachypnoea, cough, vomiting, weight loss
  • usually a result from embolus of dead worm, not due to the presance of the worms themselves -> severe dyspnoea, haemoptysis, collapse, sudden death.
22
Q

Pathophysiology of heartworm in cats

A
23
Q

Diagnosin heartworm in cats

A
  • antibody test - early as 8 weeks post-infection
  • Antigen test if > 1 adult female
  • Radiograph changes HARD

+/- bronchialviolar pattern

+/- enlargement of caudal lobar arteries

+/- adults on ultrasound

24
Q

Treatment of cats with heartworm

A

Prednisolone

Surgery if worms visualised in ‘reachable’ area

DON’T use adulticides!

Parasitology (30 decks)

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