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Abstract :
[en] Dictyocaulus viviparus is the aetiological agent of verminous bronchitis in cattle. Herein we describe an atypical case of parasitic pneumonitis in an adult cow.
Methods
At the end of March 2017, a 3-yr old Belgian Blue cow suddenly displayed a marked respiratory distress syndrome a few hours after C-section calving. In spite of the treatment set up by the local veterinarian, the cow died 48 hours later. The body was referred to the Veterinary Faculty of Liège (Belgium) for necropsy. Post- mortem gross examination revealed a severe, acute interstitial pneumonitis with concurrent emphysema and a significant amount of parasites (Dictyocaulus viviparus) in the bronchi. The microscopic examination confirmed the severe acute interstitial pneumonitis with foci of hemorrhages, necrosis, hyaline membranes and hyperplasia of type II pneumocytes. Larvae were also present in the alveoli and bronchioles.
Results
Altogether, theses clinical observations and lesions were compatible with a hypersensitivity reaction against worm antigens. Additionally, Baermann’s test was performed on feces collected from the cadaver and from 5 others cows kept under the same conditions. Four out of 6 cows were excreting small amounts of Dictyocaulus stage-1 larvae.
Conclusions
Parasitic pneumonia is a very common disease in first year grazing young cattle. In this case, cow’s age and disease manifestation time were very uncommon. Three-year-old cows are supposed to be fully protected against this nematode species. Moreover, in Belgium, at the end of March, livestock is still kept indoors (zero grazing winter period). Therefore, this case could highlight the hypobiotic capacity of Dictyocaulus viviparus larvae and associated « periparturient rise » phenomenon, both well known in sheep, but not described in cattle so far. We herein discuss the farming conditions that promoted such a severe parasitic respiratory disease.
