Lungworms of dogs and cats Flashcards

1
Q

What are some characteristics of metastrongyles?

A
  • Lungs or related blood vessels
  • Normally L1 in faeces
  • L1 have typically ‘kinky’ tails – helps differentiate the species
  • Normally indirect life cycles with mollusc intermediate hosts (snails and slugs)
  • Lympho-tracheal migration
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2
Q

Name two metastrongyle species of dogs

A

Angiostrongylus vasorum

Oslerus osleri

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3
Q

Name a metastrongyle species of cats

A

Aelurostrongylus abstrusus

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4
Q

Angiostrongylus vasorum is also know as?

A

The French heartworm

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5
Q

Where do adult Angiostrongylus vasorum worms live?

A

In the pulmonary artery and right ventricle

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6
Q

Describe 2 morphological features of Angiostrongylus vasorum

A

2cm long

Barber pole - ovaries and gut

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7
Q

What are the 3 hosts of Angiostrongylus vasorum?

A
  • Intermediate host – slugs and snails
  • Paratenic hosts –frogs
  • Dog/fox - main host
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8
Q

What is a paratenic host?

A

Hosts where there is no development, just allows the passing from one host to another

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9
Q

Define ovoviviparous

A

Pass eggs with the larvae already developed within them and are ready to hatch

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10
Q

Describe the life cycle of Angiostrongylus vasorum

A
  • Adults go from the heart and pulmonary artery in capillaries to the lungs, eggs almost immediately hatch into L1 larvae which then move across the alveoli, up the pharynx where they are coughed up and swallowed
  • No further development and L1 are passed out in the faeces, when they moult to L3 (temp dependant)
  • Once in the dog the L3 larvae cross the intestinal wall, mature to L4 and into L5 adults in the abdominal LN
  • Within the blood and lymphatic system they migrate via the liver and blood vessels to the heart
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11
Q

How are snails/slugs involved in the life cycle of Angiostrongylus vasorum?

A

L1 in faeces
Ingestion by slug/snail
L1 -> L3 development is temperature dependant
Slugs are ingested by dog

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12
Q

What is the PPP for Angiostrongylus vasorum?

A

5-8 weeks

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13
Q

What are the respiratory clinical signs of Angiostrongylus vasorum?

A
  • Coughing
  • Dyspnoea
  • Weight loss
  • Pulmonary hypertension
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14
Q

What are the non-respiratory clinical signs of Angiostrongylus vasorum?

A
  • Often asymptomatic but can cause sudden death
  • Coagulopathies: fluctuating haematoma/bleeding disorders. Worms secrete a range of anticoagulants
  • Neurological
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15
Q

How can Angiostrongylus vasorum be diagnosed?

A
  • Antigen SNAP test

- Radiography: Enlarged heart and pulmonary artery. Patchy alveolar and interstitial pattern.

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16
Q

How can Angiostrongylus vasorum be differentiated from other lungworms diagnostically?

A
  • L1 in faeces, trans-tracheal wash or bronchoalveolar lavage
  • ‘Dorsal notch’ on the tail of the L1
  • 300 to 400 µm
  • Baermann apparatus to detect L1
17
Q

What are 2 considerations when using a Baermann apparatus?

A

Low sensitivity

Repeat samples every 3 days

18
Q

How is Angiostrongylus vasorum treated?

A
  • Moxidectin
  • Milbemycin oxime
  • Fenbendazole
19
Q

How is Angiostrongylus vasorum controlled?

A
  • Corticosteroids
  • Cage rest during treatment (2-3 days)
  • Prophylaxis: monthly treatment with macrocyclic lactones
  • When possible, dogs should be prevented from ingesting snails or slugs.
20
Q

What is the role of foxes in the epidemiology of Angiostrongylus vasorum?

A

They act as reservoir hosts

21
Q

What is the main feature of Oslerus osleri life cycle?

A

Direct

22
Q

Where are adult Oslerus osleri worms found?

A

In nodules in the trachea

23
Q

How long is the PPP of Oslerus osleri?

A

10-18 weeks

24
Q

What is the infective stage of Oslerus osleri?

A

L1 in sputum (thick type of mucus made in your lungs)

25
Q

Describe the life cycle of Oslerus osleri

A
  • Larvated eggs/L1 are passed by the female (ovoviviparous)
  • L1 are released into the tracheal lumen, move up to the pharynx, swallowed and passed in faeces.
  • Infection of the definitive host by ingestion of L1 larvae (transmission mainly by the bitch grooming/licking its pup)
  • Upon ingestion/introduction into the mouth of the pup, L1 cross the intestinal wall, travel via the lymphatics and blood system to the lungs and trachea.
26
Q

What are the two signs of Oslerus osleri disease?

A

Tracheo-bronchitis

Coughing

27
Q

How is Oslerus osleri diagnosed?

A
  • Young dogs, 1-2 years old (PPP = 10-18 weeks)
  • Bronchoscopy to identify nodules
  • Larvae in faeces (low sensitivity)
  • Transtracheal wash or bronchoalveolar lavage cytology or tracheal swabs may reveal larvae or eggs
28
Q

Which drug is used to treat Oslerus osleri?

A

Fenbendazole

29
Q

How would you differentiate between L1 of Oslerus osleri and Angiostrongylus vasorum in the faeces of a dog?

A

Oslerus larvae have an S-shaped tail and Angiostrongylus larvae have a dorsal notch on their tail

30
Q

Where are the adults of Aelurostrongylus abstrusus found?

A

Lung parenchyma

31
Q

What are the features of Aelurostrongylus abstrusus?

A
  • Affects cats
  • Adults = 10mm
  • L1 in faeces (‘S’ shaped tail) - 350 to 400 µm
32
Q

Who are the 3 hosts of Aelurostrongylus abstrusus?

A
  • Snail intermediate host
  • Paratenic hosts = small mammal, frog, lizard
  • Definitive host = cat
33
Q

What is the PPP for Aelurostrongylus abstrusus

A

5-6 weeks

34
Q

Describe the disease features of Aelurostrongylus abstrusus

A
  • Normally asymptomatic
  • Common (~7% cats infected)
  • Coughing/respiratory disease
  • Hyperplasia of the bronchioles, alveolar ducts and pulmonary arteries
35
Q

How is Aelurostrongylus abstrusus diagnosed?

A
  • L1 in faeces – Baermann technique: fresh faecal samples within a 3-7 day period
  • L1 in transtracheal wash or bronchoalveolar lavage
36
Q

How is Aelurostrongylus abstrusus treated?

A
  • Fenbendazole: for at least 3 days, up to 7 days.

- Moxidectin, Emodepside

37
Q

Name the lungworm of dogs that has anterior cuticular rings on its tail

A

Crenasoma vulpis

38
Q

Give 3 other morphological features of Crenasoma vulpis

A
  • 1.5cm size
  • White slender
  • L1 has a straight pointed tail, no notch
39
Q

What are the pre-patent periods for the lungworms of dogs?

A

Angiostrongylus vasorum: 5-8 weeks

Oslerus osleri: 10-18 weeks