Respiratory Parasitic Infections - Pathology

()Map CARDIORESPIRATORY SYSTEM (Map) RESPIRATORY SYSTEM INFLAMMATION

In Dogs

Filaroides osleri

Linguatula serrata

Angiostrongylus vasorum

Dirofilaria immitis

Capillaria aerophila

Toxoplasmosis

Crenosoma vulpis

In Cats

Linguatula serrata

• As in dogs above

Aelurostrongylus abstrusus

Dirofilaria immitis

Capillaria aerophila

• As in dogs above

In Horses

Parascaris equorum

Dictyocaulus arnfieldi

Besnoitia bennetti

In Cattle

Dictyocaulus viviparus

Hydatid cysts

Syngamus laryngeus

In Sheep

Hydatid cysts

As in cattle (above)

Oestrus ovis

Protostrongylus spp.

• Adult worms block small bronchioles resulting in accumulation of eggs, larvae and cellular debri distal to the blockage
• Lesions resemble Dictyocaulus filaria but are fewer in numbers, lobular and at periphery of caudal lobes, they are very similar to Muellerius capillaris lesions

Muellerius capillaris

• Common in sheep and goats
• Rarely any clinical significance
• Grossly:
  • Multifocal interstitial pneumonia grossly evident as firm "lead-shot" nodules throughout the parenchyma, often with enveloping granulomatous response
  • Early stages are reddish in colour, turning later to greyish green, may calcify
  • Mostly in dorsal region of caudal lung lobes
• Histologically:
  • Damaged alveolar septa with mild fibrous thickening and lymphocytic infiltrate
  • In more developed host resistance, foci of eosinophils around larvae, hyperplastic epithelium, macrophages, giant cells
  • May be some calcification

Dictyocaulus filaria

• Most susceptible when first exposed to contaminated pasture
• Animals < 1 year old
• Pathogenesis and pathology similar to Dictyocaulus viviparus in cattle
• Bronchitis

In Pigs

Metastrongylus spp.

• Found in bronchioles and smaller bronchi
• Grossly:
  • Small grey nodules, especially along ventral border of caudal lobes
  • Adult worms in bronchi and bronchioles
• Histologically:
  • Catarrhal and eosinophilic bronchitis and bronchiolitis
  • Possibly atelectasis
• Rarely becomes extensive
• May transmit swine influenza

Ascaris suum

• May cause parasitic pneumonia during a part of its migration
• Larvae may be infected with Swine influenza
• May cause severe pneumonia in calves housed where infected pigs were housed previously
• Cause diffuse interstitial pneumonia with haemorrhage, atelectasis, interlobular oedema and emphysema