HW Dz (Cat)

Question 1

List the 4 differences between K9 and feline HW Dz

Answer 1

• Larvae are less likely to develop into adults
• Worm burden is lower (1-9 cat vs >20 dog)
• Adults that do survive have shorter life span (<2yr in cat, >5yr in dog)
• rarely demonstrate microfilaremia

Question 2

3 reasons microfilaremia is rare in a cat

Answer 2

• Low worm burden makes it more likely that a unisex infection is present
• Adult worms may be more likely to be sterile in the cat
• Immune system is more likely to remove the microfilaria from the circulation

Question 3

What is Aberrant Larval Migration?

Answer 3

a situation where the HW larvae do not travel to the appropriate location (ie. heart and pulmonary vessels) but instead migrate to unusual or abnormal locations

Question 4

Where can aberrant larval migration occur?

Answer 4

eye
brain
SQ tissue

Question 5

How does a cat’s immune system react to HW Dz?

Answer 5

• Villous endarteritis (like in dogs)
• Cats have specialized pulmonary intravascular macrophage (PIM) in the capillary beds of the lungs respond quickly to L5 larvae resulting in significant radiographic changes and respiratory signs

Question 6

What conditions are rare in cats but are seen in dogs when it comes to HW Dz?

Answer 6

right sided heart failure
cor pulmonale
caval syndrome

Question 7

Common clinical signs seen with feline HW Dz

Answer 7

a. Acute death usually secondary to acute lung injury
b. Asymptomatic with no clinical signs or radiographic changes
c. Chronic clinical sings
i. Acute lung injury
ii. Coughing
iii. Dyspnea
iv. Vomiting
v. Lethargy
vi. Anorexia
+/- weight loss

Question 8

Pros/cons antigen test feline HW

Answer 8

• very specific, so you can trust a positive result

- may miss infection with young adult or all male populations

Question 9

Pros/cons with antibody tests in feline HW Dz

Answer 9

• indicate either a current infection or a recently cleared infection
• can get false positives

Question 10

What combo of testing is usually needed to diagnose HW Dz in cats

Answer 10

antigen test
antibody test
PE
CBC
Thorax rads

Question 11

Is there an approved adulticide for cats?

Answer 11

No

Question 12

Current recommendation for treating an asymptomatic cat

Answer 12

allow worms to die naturally on their own without adulticide therapy; keep P indoors with restricted exercise

Question 13

Current recommendation for treating a cat with clinical signs of HW Dz

Answer 13

generally still no adulticide treatment, but supportive therapies may be recommended

Question 14

3 Available products to prevent HW in cats

Answer 14

a. Ivermectin (Heartguard for cats)
b. Milbemycine oxime (Interceptor)
c. Selemectin (Revolution)

Question 15

Nursing strategies for cats with HW Dz

Answer 15

• recheck q4-6months with complete PE and Thx rads
• if lung Dz present, may send decreasing dose regimen of corticosteroids
• rest is imperative

Question 16

Supportive measures for HW+ cats that present with signs of respiratory Dz

Answer 16

• O2 via O2 tent or cate
• IVF and nutritional support if anorexic/vomiting
• bronchodilators and/or cough suppressants if coughing or dyspnea

Question 17

What O should know about feline HW Dz

Answer 17

a. Explain how cats can become infected as well as how cats respond to the presence of HWs
b. Explain why you aren’t actually treating the Dz
c. Exercise restrictions, meds given, and recheck appointments should be emphasized
d. Give O a list of clinical signs: anorexia, vomiting, coughing, dyspnea, tachypnea, respiratory distress, weight loss
e. Cats survive this disease