C. jejuni mammary infection in cattle : case report

INTRODUCTION - The contamination of bulk milk from pathogenic microorganisms such as C. jejuni is assuming more importance as a consequence of the increasing consumption of raw milk.We describe two cases of dairy farms located in the Po Valley, characterised by repeated detection of C. jejuni in bulk milk. In both cases the source of contamination of bulk milk (and consequently of raw milk) was due to a cased of mammary infection in a cow. CASES - In both cases just one infected quarter of a single cow was able to contaminate the bulk milk of respectively 270 and 180 lactating cows. The persistent infection of the quarter was documented for at least 90 days in one herd and for 30-40 days in the other herd. Antibiotic treatment of the infected cow in the first farm was effective in the cure of mammary infection. DISCUSSION AND CONCLUSIONS - Although C. jejuni was also detected in the faeces of some animals, the segregation of the subject with mammary infection was effective in eliminating the primary source of contamination, with the result of an undetectable level of the microrganism in bulk milk. The analysis of pooled milk samples by culture and PCR, followed by individual testing, prooved to be efficient tools for the identification of infected subjects. These data demonstrate the importance to consider the possibility of udder infection of even a single cow, as a source of bulk milk contamination, when C. jejuni is repeatedly detected.