Excretion of Streptococcus pyogenes in the milk of naturally infected cows

Abstract

An account is given of two cows which were concerned in milk-borne Streptococcus outbreaks at Mørkøv (Denmark) and Doncaster (England) respectively, and. which were afterwards kept under close observation. The Danish cow excreted Str. pyogenes from the affected quarter for at least 13 months, including a dry period of about 3 months; the other animal excreted similar streptococci for about 6 weeks. In both cases there were stages when symptoms of mastitis were either not evident or not pronounced, although the milk was known to be infective.