Capillaria contorta parasitism in red-legged partridge under farm conditions in Spain: histopathology of the upper digestive system

Abstract

Capillaria contorta is a parasitic nematode of the oesophagus and crop of a number of domestic and wild birds. This study deals with three cases of capillariasis in the red-legged partridge. Infected individuals in two of these cases presented a history of weight loss, weakness, feather alterations and death, while morbidity and mortality were limited. In the third case, deaths occurred only after the birds were freed for repopulation purposes. Congestion of the crop was seen at necropsy. Histological examination revealed the presence of parasites and their eggs in the epithelium of the oesophagus and crop of every partridge. The worms displayed a characteristic distribution in all three cases: adults were found in the basal portion of the epithelium while the eggs were located in the middle. In one bird, parasites were observed in the anterior segment of the proventriculus. The fundamental epithelial lesion consisted of spongiosis of the oesophagus and crop. In the individual with proventricular parasitism, epidermoid metaplasia was also seen. The inflammatory reaction observed in the lamina propria was discrete and diffuse, except in those cases in which epithelial necrosis and bacterial colonies were detected.

Keywords::

• Capillaria
• crop
• histopathology
• oesophagus
• parasitism
• partridge