Difference between revisions of "Respiratory Parasitic Infections - Pathology"

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===[[Coccidia|''Besnoitia bennetti'']]===
+
===[[Coccidiosis - Horse|''Besnoitia bennetti'']]===
  
 
==In Cattle==
 
==In Cattle==
  
===[[Trichostrongyloidea|''Dictyocaulus viviparus'']]===
+
===''[[Dictyocaulus viviparus]]''===
[[Image:Dictyocaulus viviparus.jpg|right|thumb|100px|<small><center>Dictyocaulus viviparus (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
 
[[Image:Parasitic bronchitis.jpg|right|thumb|100px|<small><center>Parasitic bronchitis (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
 
*Found in [[Trachea Inflammatory - Pathology#Infectious causes of tracheitis|trachea]] and [[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|large bronchi]]
 
*Causes parasitic bronchitis, synonyms: bovine dictyocauliosis, husk, hoose
 
*Primary infection:
 
**Penetration phase (week 1)
 
***Larvae migrate to lungs, no clinical signs
 
**Prepatent phase (weeks 1-3)
 
***Development and migration of larvae -> [[Bronchi and Bronchioles Inflammatory - Pathology#Bronchiolitis|bronchiolitis]] -> eosinophilic exudate -> air passage blocked -> alveolar collapse (distal to blockage) -> clinical signs (tachypnoea, coughing)
 
**Patent phase (weeks 4-8)
 
***Egg-producing mature worms
 
***[[Bronchi and Bronchioles Inflammatory - Pathology#Bronchitis|Bronchitis]] - due to mature worms
 
***[[Lungs Inflammatory - Pathology#Verminous pneumonia|Parasitic pneumonia]] - due to aspiration of eggs and larvae -> cellular infiltration of [[Neutrophils|neutrophils]], macrophages, giant cells
 
**Postpatent phase (weeks 8-12)
 
***Majority of worms are expelled
 
***In 25% of cases clinical signs may reappear as a result of alveolar epithelialisation
 
***May be together with [[Lungs Ventilation - Pathology#Emphysema|interstitial emphysema]] and [[Lungs Circulatory - Pathology#Pulmonary oedema|pulmonary oedema]], or secondary bacterial infection
 
*Reinfection syndrome:
 
**Immune cattle show clinical signs only if exposed to large numbers
 
**Pathogenesis - large numbers of larvae reach bronchioles where they are killed by immune response
 
**Pathology - parasite granulomata (grey-green, 5mm diameter, macrophages, giant cells, eosinophils) and eosinophilic plugs in bronchioles
 
<small>Above from RVC Parasitology study guide (2005-2006)</small>
 
*Preferentially in dorsocaudaland ventrocaudal regions
 
  
*Histologically
 
**Bronchial epithelium may show hyperplasia due to the chronic irritation
 
**Cross-sections of the parasites
 
**Exudate contains many eosinophils
 
**Foci of necrosis in the rest of the lung tissue due to aspiration of eggs and larvae fromhese adults
 
**In mild infestations, the adults are normally expelled in two months - self cure
 
*Repeated infestation and secondary bacterial infection are common
 
 
*Two other types of lesion in lung tissue due to this worm have been reported:
 
**Nodules (2-4mm in diameter) with greenish centres in the reinfection of an immune animal - the host mounting a successful defence and preventing larval migration
 
**Pulmonary oedema and emphysema - thought to be a hypersensitivity response to a massive invasion of larvae in previously- sensitised animals - the gross and microscopic appearance is similar to that of [[Lungs Inflammatory - Pathology#Acute bovine pulmonary emphysema and oedema (ABPEE)|fog fever]]
 
  
 
===Hydatid cysts===
 
===Hydatid cysts===

Revision as of 09:25, 1 July 2010


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()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

Echinococcus cysts (Image sourced from Bristol Biomed Image Archive with permission)
  • The intermediate stage of Echinococcus granulosus can be found in the lungs of many species, most commonly in lungs of cattle and sheep
  • They range in size up to 5-10 cm diameter and although of little clinical significance, are important as a zoonosis (can be upto football size in man) and because of carcass condemnation







Syngamus laryngeus

  • In larynx of cattle in Asia and South America

In Sheep

Hydatid cysts

As in cattle (above)

Oestrus ovis

Media:Oestrus ovis.mp4

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