Detection of subclinical bovine mastitis caused by mycoplasmosis by indirect ELISA test and isolation

Abstract

THE OBJECTIVE OF THIS STUDY WAS TO DETERMINE THE EFFECTIVENESS OF ELISA TEST IN SERUM, FOR THE DIAGNOSIS OF SUBCLINICAL BOVINE MASTITIS CAUSED BY MYCOPLASMA BOVIS, HAVING AS A REFERENCE TEST, THE ISOLATION OF THE MICROORGANISM IN MILK SAMPLES. TWO HUNDRED AND TWENTY FIVE BLOOD AND MILK SAMPLES WERE OBTAINED FROM HERDS FROM THE STATE OF MEXICO, COAHUILA AND HIDALGO, ALL OF THEM IN MEXICO. USING THE WISCONSIN TEST, 139 SAMPLES (61.8%) WERE POSITIVES TO SUBCLINICAL MASTITIS BUT ONLY IN SIX OF THEM, MYCOPLASMA BOVIS WAS ISOLATED. BY ELISA TEST, 72 SAMPLES WERE POSITIVES (32.0%). ALL ANIMALS WITH POSITIVE ISOLATION WERE ALSO POSITIVE TO THE ELISA TEST. WITH A CUT POINT HIGHER OR EQUAL TO 100, SENSITIVITY AND SPECIFICITY WERE 83.3% AND 83.56%, RESPECTIVELY, ALTHOUGH THE POSITIVE PREDICTIVE VALUE (PV) () WAS 12.2% AND THE NEGATIVE PREDICTIVE VALUE (PV) ("") WAS 99.46%. THE LOW PV () WAS ASSOCIATED TO A LOW PREVALENCE. ELISA TEST COULD BE USED AS A SCREEN TEST TO DETECT MASTITIS ASSOCIATED TO MYCOPLASMA BOVIS, PARTICULARLY IN HERDS WITH HIGH FREQUENCIES (> 10%), THIS WITH THE PURPOSE TO IMPROVE A POSITIVE PREDICTIVE VALUE (PV), WHICH WOULD ALLOW TO ESTABLISH BETTER DIAGNOSES IN CASES WHERE THE MOST COMMON TESTS DO NOT GIVE A SPECIFIC RESULT, MOSTLY IF ELISA TEST IS CONSIDERED AS PRACTICAL, FAST AND ECONOMIC.