Outbreak of fatal nitrate toxicosis associated with consumption of fennels (Foeniculum vulgare) in cattle farmed in Campania Region (Southern Italy)

Nitrate and nitrite are toxicants which have become increasingly significant environmental chemicals. An increase in environmental distribution of nitrogenous compounds, especially in surface and ground water has been attributed to the intensive use of nitrate as agricultural fertilizers and to increasing amounts of nitrogenous wastes produced by municipalities, industries and feedlots. The purpose of this study is to illustrate a fatal nitrate toxicosis in cattle associated with the consumption of fennels (Foeniculum vulgare). Fifteen cows from the same farm suddenly developed weakness, muscular tremors, respiratory distress and finally anoxic convulsions. Affected animals died within 24 to 48 hours from the onset of the clinical signs. Five cows underwent a complete post-mortem examination. In all examined animals, gross lesions included presence of dark uncoated blood around the nostrils and the anal region, moderate inflammation of the gastrointestinal mucosa, and brown discoloration of the skeletal muscles and kidneys. The histological examination showed tubular degeneration and congestion of glomerular vessels in the kidney. Toxicological analysis detected high levels of nitrates in the fennels used to feed the animals. The source of exposure to nitrates was identified in the fennels. The fennels were grown in a polluted area of Campania region and distributed in a public market for human consumption. The waste from the sale of the fennels were collected and fed the cows. The accumulation of nitrates in some vegetables pose a risk not only for animal health but also for human and environmental safety.