Pulmonary Parasites

Question 1

What is the most common pulmonary parasite in dogs?

Answer 1

Angiostrongylus Vasorum (French heart worm)
Aka canine lungworm

Question 2

What is the lifecycle of A Vasorum?

Answer 2

Indirect (snails as IH)
L1-3 develops in snails
Dog eats snail
L4 migrates via mesenteric lymph nodes to portal vein in liver
migrates through vena cava to right ventricle
Adult live in pulmonary artery and lays eggs in capillaries
L1 penetrates capillaries in alveolar wall
L1 coughed up and swallowed
L1 shed in faeces

Question 3

Why are the clinical signs for A Vasorum so diverse?

Answer 3

• Adult antigens
  ○ Cause Type III hypersensitivity (immune complex deposition)
  ○ Complement activation
  ○ Immune infiltrate in lungs and other tissues
• Egg deposition/L1 migration
  ○ Pulmonary inflammation/granuloma formation
  ○ Pulmonary arteriolar vasoconstriction
  ○ End arteritis and fibrosis of vessels

Question 4

Clinical signs of A Vasorum

Answer 4

Cardiorespiratory signs
Coagulopathies
Neural dysfunction

Question 5

Cardiorespiratory clinical signs of A Vasorum

Answer 5

Chronic cough
+/-Productive
Exercise intolerance, syncope
Dyspnoea
Tachypnoea

Question 6

Coagulopathy signs of A Vasorum

Answer 6

Anaemia
Subcutaneous haematomas
Internal haemorrhages
Thrombocytopenia (can be immune mediated)
Thrombopathia

Question 7

Neural signs of A Vasorum

Answer 7

Paresis
Depression
Seizures
Spinal pain
Ataxia

Question 8

What’s causes the clinical signs of A Vasorum?

Answer 8

Clinical signs caused by either adults in arteries of migration of larvae

Cough due to larvae penetrating alveoli from blood vessels

Question 9

How to diagnose A Vasorum

Answer 9

Faecal flotation (need multiple samples)
Possible via BAL
Suggestive clinical signs
SNAP tests but not very sensitive n(False negatives)
Supportive radiographic evidence showing interstitial pattern

Question 10

Management/prevention of A Vasorum

Answer 10

Licensed products:
○ Advocate/Prinovox
(Imidacloprid and moxidectin)
○ Milquantel/Milbemax/Milbactor
(Milbemycin oxime and praziquantel)
Unlicensed products:
○ Fenbendazole for 7-21 days
(Levamisole and ivermectin)

Question 11

Supportive treatment in addition to anthelmintics for A Vasorum

Answer 11

Bronchodilators
Corticosteroids
Phosphodiesterase inhibitors
Cage rest/oxygen therapy

Question 12

Which cardiorespiratory parasites affect dogs?

Answer 12

Olesrus osleri
Fliaroides spp.
Crenosoma vulpis
Angiostrongylus vasorum

Question 13

Which cardiorespiratory parasites affect cats?

Answer 13

Aelurostrongylus abstrusus

Question 14

Olesrus osleri

Answer 14

PPP = 10-18 weeks
Form nodules in bronchi/bronchioles from around 2 months from infection
Clinical signs:
* Chronic cough
* Dry rasping
* Notable in younger dogs

Bronchoscopy useful to identify nodules

Question 15

Treatment for Olesrus osleri

Answer 15

Nodules may remain and calcify
Fenbendazole for 10 days
Often needs repeating after 4 weeks

Question 16

Filaroides hirthi

Answer 16

Same lifecycle as Oslerus osleri
Infection generally asymptomatic
Worms live in alveoli
Diagnosis usually found PM
Radiographs often show diffuse broncho-interstitial patterns
Rarely alveolar pattern
Treatment rarely indicated
Treat as Oslerus osleri

Question 17

Crenosoma vulpis

Answer 17

Usually parasite of wolves and foxes
Occasionally affects dogs
Leads to chronic bronchopulmonary disease and productive cough
Indirect lifecycle involves slugs/snails
PPP 3 weeks
Adults live in bronchi and bronchioles
○ NO NODULES
Investigate and treat as Oslerus osleri