Mechanism of recurrent outbreak of the scarlet fever epidemics in mainland China

In mainland China, most infectious diseases occur once a year, except for scarlet fever, which has been steadily breaking out twice a year in recent years. Over the years, the recurrence of scarlet fever, a contagious disease characterized by a distinctive red rash, has been a focus of attention. However, the oscillatory mechanism of scarlet fever remains unclear. This study aimed to uncover how meteorological factors contribute to the recrudescence of scarlet fever in mainland China. The study used a longitudinal public dataset covering 31 provinces in mainland China, containing 14 years of monthly scarlet fever infections, along with available local meteorological data. Power spectrum analysis was conducted on time series data, and correlation analyses were performed to assess the relationship between the oscillatory nature of epidemics and meteorological factors. We found that the scarlet fever epidemics generally occur twice a year in various provinces of China, and the timing of these outbreaks’ peaks progressively from southern to northern regions. Furthermore, we established an atlas that shows the relationship between scarlet fever oscillation and meteorological factors. Our findings indicated a significant correlation between the oscillation characteristics of scarlet fever in 50% of provinces and each natural meteorological factor. Our study presents a detailed description of the temporal and spatial changes in the oscillatory characteristics of scarlet fever for the first time and explores the oscillatory characteristics of natural meteorological conditions and their correlation with the number of scarlet fever infections. These findings could serve as a valuable guide for government prevention and control measures for the scarlet fever epidemic.