A possible tremorgenic mycotoxicosis by Roquefortine C in a bovine herd

A total of 15 beef cows and calves were referred for history of neurological signs. The animals (12/15 Chianina breed, 3/15 Limousine) were grazing in 300 ha area, fed with grass and hay. Inspection of the hay reveled macroscopic alterations, consisting of diffuse and heavy mold contamination of many hay bales. Due to the not cooperative attitude, the animals were only visually examined in the field; the neurological signs observed were ataxia, intentional head tremors and muscle twitching. Only 3 calves with severe neurological signs were housed in a medication area and underwent a complete clinical exam. All 3 calves showed intentional head tremors and muscle twitching; 1/3 presented severe ataxia and stiffness gait, while 2/3 calves were recumbent and unable to rise. The most important clinical data were: hyperthermia, tachypnea, tachycardia and long capillary refill time. The neurological examination showed deficits of V and VII cranial nerves. Calves could swallow, but they were unable to grab the food. Based on history and clinical examination the following differential diagnoses were considered: tremorgenic mycotoxicosis, nervous ketosis, nervous BVD form, BHV1-5, Listeriosis and WMD. Blood samples were collected for CBC count and biochemistry panel (TP, urea, creatinine, total and direct bilirubin, GGT, AST, CPK, Mg, Se and vit E), urinalysis was performed for ketone bodies. Calves were also tested for infectious diseases (Listeriosis, BVD, BHV 1-5). Multiple samples of altered hay were analyzed for mycotoxins and hay balls were removed in all animals’ stock. The grazing animals recovered spontaneously within 1 week along with 2/3 hospitalized calves, while 1/3 calf was euthanized due to poor general conditions. CBC, biochemistry panel, vit E and oligo-minerals resulted within normal ranges and no positivity for infectious agents were detected. Food analysis showed high concentrations of roquefortine C (RC): 345 μg/kg DM. Presence of RC in livestock food is highly reported, in particular in visibly moldy areas (1). RC intoxication causes anorexia, paralysis and several reports attribute it neurotoxic properties (2). In mice experimental intoxications induced muscle contractions, ataxia, prostration and intermittent seizures. RC intoxication, resembling penitrem A (PA) intoxication, has been reported in dogs. Moreover, RC is considered a sensitive biomarker for PA exposure. PA is a tremorgenic fungal toxin which intoxication causes ataxia, tachypnea, and sustained tremors. The pathophysiological mechanism by which mycotoxins affect the CNS is unknown but the biochemical lesions are reversible. Diagnosis is based on the clinical signs, demonstration of the mycotoxins in the feed and identification of the fungal elements in blood and feces. Affected animals recover completely when they are removed from infected pastures. Based on neurological signs, recovery after altered food removing and results of food analysis, the diagnosis of tremorgenic intoxication was hypothesized. Limits of this report are: lack of PA dosage in the food and lack of RC and PA evaluation in blood and feces of affected animals.