Interacción de cepas verocitotóxicas de Escherichia coli y rotavirus en un brote de diarrea en becerros

Abstract

AN OUTBREAK OF DYSENTERIC DIARRHOEA IN CALVES OF 1 TO 20 DAYS OF AGE, WITH AN ACUTE COURSE CHARACTERIZED BY GASTROENTERIC OEDEMA, NERVOUS SIGNS AND ANTIBIOTIC TREATMENT FAILURE WAS STUDIED. TESTS FOR PARASITE, BACTERIA AND ROTAVIRUS WERE CARRIED OUT. ESCHERICHIA COLI VEROTOXIN PRODUCING STRAINS (VEROTOXIN OR SHIGA-LIKE TOXIN, STX) WERE POSITIVE IN 63.7% OF THE E.COLI ISOLATES, CORRESPONDING TO 86.5% OF THE DISEASED ANIMALS. ROTAVIRUS WAS DETECTED IN 24% OF THE SICK CALVES BY DIFFERENCES IN THE RNA MIGRATING PATTERNS WERE PRESENT. IN ALL ANIMALS POSITIVE TO ROTAVIRUS, E.COLI STX STRAINS WERE IDENTIFIED. THE PERCENTAGE OF CALCULATED RISK WAS 100% WHERE E.COLI STX INFECTION COULD INDUCE ROTAVIRUS; MEANWHILE STX STRAINS INFECTION REMAINED INDEPENDENT FROM THE VIRAL DISEASE. THESE RESULTS POINT OUT THAT E.COLI STX STRAINS COULD BE THE PRIMARY AETIOLOGICAL AGENT OF NEONATAL TOXAEMIA ON CALVES, AND STRONGLY REINFORCE THE IMPORTANCE OF THE BOVINES AS RESERVOIRS OF THESE CITOTOXIC BACTERIA INVOLVED IN THE HUMAN HAEMOLYTIC UREMIC SYNDROME.