Authors: Martha Powell, Future Science Group
Scientists have carried out a population-based molecular epidemiological study on scarlet fever, demonstrating that a new dominant linage of Streptococcus pyogenes with increased toxin production has emerged.
In 2014 England saw the biggest surge in scarlet fever cases since the 1960s at 15,000. This continued to rise across 2015 and 1016 with 17,000 and over 19,000 scarlet fever cases respectively. In 2016 the case increase coincided with an elevation in S. pyogenes infections, also termed Strep A.
In this study, published recently in the Lancet Infectious Diseases, the authors aimed to identify the Strep A stains causing infections in the UK, as defined by the emm gene present. The team discovered that during 2014 the dominant emm genes were emm3 and emm4; however, in the spring of 2015 and 2016 emm1 strains became dominant, in 2016 it became the single most frequent strain at 33%.