JPC SYSTEMIC PATHOLOGY

RESPIRATORY SYSTEM

SEPTEMBER 2017

P-P12

 

Signalment (JPC 2017865):  3‑year old Rambouillet ewe

HISTORY:  Death following a clinical course of anorexia, depression, and dyspnea

HISTOPATHOLOGIC DESCRIPTION:  Lung:  Approximately 60% of the pulmonary architecture is atelectic and/or consolidated and there is a multifocal to coalescing basophilic cellular infiltrate centered on and surrounding bronchioles. Within larger bronchiolar lumina, there are cross and tangential sections of adult nematodes that are 350 um in diameter, with a 4‑5 um thick cuticle, polymyarian-coelomyarian musculature, prominent lateral cords, a pseudocoelom, reproductive organs containing embryonated eggs, and a medium-sized intestine composed of multinucleated cells lined by short microvilli. Within other bronchiolar lumina, there are eosinophils, viable and degenerate neutrophils, fewer lymphocytes, plasma cells and macrophages admixed with sloughed bronchiolar epithelium, fibrin and debris. Multifocally, bronchiolar epithelium is hyperplastic, up to 5 cell layers thick in both affected and less affected areas of the lung, and there is peribronchiolar lymphoid hyperplasia which is admixed with variable numbers of macrophages and moderate amounts of fibrin and edema.  Alveolar septa are moderately thickened by finely beaded, eosinophilic material (fibrin), edema, lymphocytes and macrophages.  Within smaller bronchiolar lumina and adjacent alveoli, there are few tangential sections of 20-30 um diameter nematode larvae that have 1-2 um thick cuticle, dark basophilic nuclei within the body cavity, and a variably distinct digestive tract.  Admixed within these areas are variable numbers of macrophages, neutrophils, lymphocytes, plasma cells and eosinophils, fibrin, and edema.  There is mild alveolar emphysema and the pleura is mildly expanded by fibrous connective tissue and edema. 

MORPHOLOGIC DIAGNOSIS:  Lung:  Pneumonia, eosinophilic, lymphoplasmacytic, multifocal to coalescing, moderate, with atelectasis, peribronchiolar lymphoid hyperplasia, bronchiolar epithelial hyperplasia and adult and larval trichostrongyle nematodes, Rambouillet, ovine 

ETIOLOGIC DIAGNOSIS:  Pulmonary dictyocauliasis

CAUSE:   Dictyocaulus filaria

GENERAL DISCUSSION:

PATHOGENESIS

LIFE CYCLE:

TYPICAL CLINICAL FINDINGS

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

Prepatent phase (from larval migration into the lungs from capillaries):

Patent phase (from nematodes in bronchi and bronchioles):

ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS:

Protostrongylus rufescens

Neostrongylus linearis:   

Muellerius capillaris

Cystocaulus ocreatus:

COMPARATIVE PATHOLOGY

Cattle and deer: 

Donkeys and Horses

Other lungworms of domestic animals include:

REFERENCES:

  1. Bowman DD. In: Bowman DD, ed. Georgis’ Parasitology for Veterinarians. 10th ed. St. Louis, MO: Saunders Elsevier; 2013:167.
  2. Chilton NB, Huby-Chilton F, Gasser RB, Beveridge I. The evolutionary origins of nematodes within the order Strongylida are related to predilection sites within hosts. Mol Phylogenet Evol. 2006 Jul;40(1):118-128.
  3. Constable PD., Hinchcliff KW., Done SH., Grunberg W.: Veterinary Medicine. 11th ed., London, UK:WB Saunders;2017:980.
  4. Gardiner CH, Poynton, SL: An Atlas of Metazoan Parasites in Animal Tissues. Washington DC: Armed Forces Institute of Pathology, American Registry of Pathology; 2006: 22,29.
  5. Lopez A, Martinson SA: Respiratory system, mediastinum, and pleurae. In: Zachary JF. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Mosby Elsevier; 2017:539.
  6. Uzal FA., Plattner BL., Hostetter JM. Alimentary system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 2. 6th ed. Philadelphia, PA: Elsevier; 2015:565-567,574.

 

 


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