Related Experiment Video
Updated: Nov 2, 2025
Author Spotlight: Advancements in Understanding and Combatting Shigella Infections
Published on: February 9, 2024
Relative transmissibility of shigellosis among different age groups: A modeling study in Hubei Province, China
Zeyu Zhao1, Qi Chen2, Yao Wang1
1State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen City, Fujian Province, People's Republic of China.
Insights
Shigellosis transmission is highest among children under 5, who also show the greatest infectivity. Interventions targeting this age group and the 25-59 year olds are crucial for reducing disease burden.
Area of Science:
- Epidemiology
- Mathematical Modeling
- Public Health
Background:
- Shigellosis poses a significant health challenge in China, particularly affecting children under five.
- Understanding age-specific transmission dynamics is crucial for effective control strategies.
Purpose of the Study:
- To investigate age-related factors influencing shigellosis transmission in China.
- To identify key age groups for targeted public health interventions.
Main Methods:
- An age-specific Susceptible-Exposed-Infectious/Asymptomatic-Recovered (SEIAR) model was employed.
- Analysis utilized shigellosis surveillance data from Hubei Province (2005-2017).
- Age groups analyzed: ≤5, 6-24, 25-59, and ≥60 years.
Main Results:
- The SEIAR model demonstrated a strong fit with observed shigellosis data (P < 0.001).
- Highest transmissibility (Reff) was observed from the ≤5 years group to the 25-59 years group (mean: 0.76).
- The ≤5 years group exhibited the highest infectivity (RI = 1.71), while the 25-59 years group showed the highest susceptibility (RS = 2.51).
Conclusions:
- Children under 5 years are key reservoirs of shigellosis infectivity.
- Adults aged 25-59 years are highly susceptible and play a role in transmission.
- Targeted interventions focusing on the ≤5 and 25-59 year age groups are recommended to curb shigellosis spread.
Abstract:
Shigellosis is a heavy disease burden in China especially in children aged under 5 years. However, the age-related factors involved in transmission of shigellosis are unclear. An age-specific Susceptible-Exposed-Infectious/Asymptomatic-Recovered (SEIAR) model was applied to shigellosis surveillance data maintained by Hubei Province Centers for Disease Control and Prevention from 2005 to 2017. The individuals were divided into four age groups (≤ 5 years, 6-24 years, 25-59 years, and ≥ 60 years). The effective reproduction number (Reff), including infectivity (RI) and susceptibility (RS) was calculated to assess the transmissibility of different age groups. From 2005 to 2017, 130,768 shigellosis cases were reported in Hubei Province. The SEIAR model fitted well with the reported data (P < 0.001). The highest transmissibility (Reff) was from ≤ 5 years to the 25-59 years (mean: 0.76, 95% confidence interval [CI]: 0.34-1.17), followed by from the 6-24 years to the 25-59 years (mean: 0.69, 95% CI: 0.35-1.02), from the ≥ 60 years to the 25-59 years (mean: 0.58, 95% CI: 0.29-0.86), and from the 25-59 years to 25-59 years (mean: 0.50, 95% CI: 0.21-0.78). The highest infectivity was in ≤ 5 years (RI = 1.71), and was most commonly transmitted to the 25-59 years (45.11%). The highest susceptibility was in the 25-59 years (RS = 2.51), and their most common source was the ≤ 5 years (30.15%). Furthermore, "knock out" simulation predicted the greatest reduction in the number of cases occurred by when cutting off transmission routes among ≤ 5 years and from 25-59 years to ≤ 5 years. Transmission in ≤ 5 years occurred mainly within the group, but infections were most commonly introduced by individuals in the 25-59 years. Infectivity was highest in the ≤ 5 years and susceptibility was highest in the 25-59 years. Interventions to stop transmission should be directed at these age groups.
