The relative transmissibility of shigellosis among male and female individuals in Hubei Province, China: a modelling study

Objective Shigellosis has been a heavy burden in China. However, its relative transmissibility in male and female individuals remains unclear. Method A Susceptible–Exposed–Infectious/Asymptomatic–Recovered (SEIAR) model was applied to explore the dataset of reported shigellosis cases built by Hubei Province from 2005 to 2017. Two indicators, secondary attack rate (SAR) and relative ratio of SAR between males and females, were developed to assess the relative transmissibility in males and females. Results The number of cases and reported incidences in males and females demonstrated a significant decreasing trend (Male trend: χ2 = 11.268, P = 0.001, Female trend: χ2 = 11.144, P = 0.001). SEIAR model had a great fitting effect with the data of shigellosis (P < 0.001). Our simulation revealed that, when parameter βfm = 0, the greatest decrease in cases were obtained for different genders. The median value for SARmm was 2.3225 × 10-8 (Range: 1.7574 × 10-8 – 3.8565 × 10-8), SARmf was 2.5729 × 10-8 (Range: 1.3772 × 10-8 – 3.2773 × 10-8), SARfm was 2.7630 × 10-8 (Range: 1.8387 × 10-8 – 4.2638 × 10-8) and SARff was 2.1061 × 10-8(Range: 1.0201 × 10-8 – 3.2140 × 10-8). The median value of relative ratio calculated by SAR in mm versus (vs) mf was 0.93 (Range: 0.75 – 1.47), mm vs fm was 0.90 (Range: 0.41 – 1.81), mm vs ff was 1.07 (Range: 0.55 – 2.93), mf vs fm was 0.99 (Range: 0.32 – 1.25), mf vs ff was 1.17 (Range: 0.43 – 3.21) and ff vs fm was 0.75 (Range: 0.35 – 1.06). Conclusion Transmissibility of shigellosis is different among male and female individuals. Shigellosis seems to be more transmissible in males than in females.