Heartworm Disease Flashcards
Dirofilaria
Adult Heartworm
* live in pulmonary artery and right ventricle - cause right ventricular hypertrophy
* L3 larvae transmitted into host via mosquito bite
* live 3-5 years
* dogs develop higher worm count than cats
Bacteria in Heartworm
Wolbachia
* bacteria that infects HW itself
* doxycycline used to treat
* killing this will help make HW treatment more effective
Heartworm in Dogs
C/S
Signs may be consistent with right heart failure
* exercise intolerance
* cough
* dyspnea
* ascites
Heartworm in Cats
Acute and Severe C/S
- Salivation
- Tachycardia
- Shock
- Neurologic
- Sudden Death
Heartworm in Cats
Chronic C/S
- HARD
- Vomiting
- Weight Loss
Heartworm
HARD
Heartworm-Associated Respiratory Disease
* chronic signs in cats
* appear similar to asthma - coughing and wheezing
Diagnose Heartworm
in Dogs
Heartworm Antigen Test
Test of choice
* detects antigen from adult female worms
Diagnose Heartworm
in Dogs
Modified Knott’s Test
May detect microfilaria
* less sensitive than antigen test
Diagnose Heartworm
in Dogs
Other Tests
- Radiograph - right sided cardiac enlargment
- Enlarged pulmonary arteries
- Proteinuria
- Increased eosinophil count
Diagnose Heartworm
in Cats
Heartworm Antigen Test
May have false negatives
* low worm count
* all-male infections can occur
Diagnose Heartworm
in Cats
Heartworm Antibody Test
Indicates exposure
* may not indicate an active infection
Diagnose Heartworm
in Cats
Antigen and Antibody Tests both required
* interpret in light of C/S
* radiographs +/- echocardiogram can aid diagnosis
Heartworm Treatment
Dogs
Treatment of Choice: Melarsomine (Immiticide)
* “split injection” protocol
* give 1 injection; wait 4-6 weeks; give 2 injections 24 hrs apart
* confine after treating - reduces thromboembolism risk
Heartworm Treatment
Dog
“Slow Kill”
Treatment NOT recommended
* give monthly prevention and wait for adults to die
Heartworm Treatment
Cats
Do not tolerative Melarsomine (Immiticide)
* treat symptomatic with bronchodilators +/- corticosteriods
* wait for worm to die (2-3 year lifespan)
