Peracute Alpha-Naphthylthiourea Intoxication In A Cow-Calf Herd

This article describes the intoxication of a cow-calf herd (100 animals) with alpha-naphthylthiourea (ANTU), resulting in 10 deaths. The rodenticide, which is not licensed for use in the European Union, might have been introduced into the herd via imported hay or given to the animals maliciously.Most of the intoxicated animals presented with a peracute condition and sudden death. Clinical signs observed in affected animals included anorexia, rumen stasis, foamy discharge from mouth and nostrils, dyspnea, crackling lung sounds, and abdominal tympanic sounds during acoustic percussion and tachypnea with prominent rib movements. The affected animals were treated symptomatically with glucose, metamizole sodium, caffeine, calcium gluconate, magnesium gluconate and medicinal charcoal. In addition, non-pregnant cows were given dexamethasone. Morbidity among the herd was 13% (13/100) and the case fatality rate was 76.9% (10/13). Post-mortem examination of all cattle carcasses determined cyanotic mucous membranes, serosanguineous liquid containing gelatinous particles in the thoracic cavity and severe lung edema. Histological investigations of lung tissue samples determined a severe and fibrin-rich alveolar and interstitial edema, a mild alveolar histiocytosis and a discrete emigration of granulocytes into alveolar lumens in few locations.A diagnosis of ANTU intoxication was made. The rodenticide was detected in tissue samples by thin layer chromatography. To our knowledge, this is the first description of ANTU poisoning within a cattle herd. Since ANTU is still a commonly used rodenticide in many countries, ANTU intoxication should be considered in herds where a substantial number of cattle present with a progressive peracute disease with clinical signs of a white foamy discharge from the mouth and nose, tachypnea and lung edema, leading to high mortality rates.