RESUMO
To simulate intervention measures in controlling an outbreak of acute hemorrhagic conjunctivitis on one school campus by using the Susceptible-Infected-Recovered (SIR) model, to provide evidence for preparedness and response to the epidemic. Classical SIR model was used to model the epidemic. Malthusian exponential decline method was employed to estimate the infective coefficient β for interventions. The initial value of parameters was determined based on empirical data. The modeling was implemented using Matlab 7.1 software. Without interventions, the outbreak was expected to experience three phrases: (1)early stage (the first 5 days) in which the epidemic developed slowly and could be intervened easily; (2) rapid growing stage (6-15 days) in which the number of infected cases increased quickly and the epidemic could not be well controlled;and (3) medium and late stage (16 days and later) in which more than 90% of the susceptible persons were infected but the intervention measures failed to prevent the epidemic. With the implementation of interventions, the epidemic was predicted to be controlled in the early stage, under the SIR model. The simulation based on the SIR model kept an acceptable consistency with the actual development of epidemic after the implementation of intervention measures. The SIR model seemed effective in modeling interventions to the epidemic of acute hemorrhagic conjunctivitis in the schools.
RESUMO
Objective To determine the incidence of non-fatal injuries and related influencing factors among children under 5 years old in China. Methods Data involving 10 819 children under 5 years old was from the Fourth National Health Service Survey of China. Injury-related indicators include: history of ever having had an injury, its frequency, cause, location and severity of the injury.A two-level Poissun regression was used to examine the significance of related socio-economic variables. Results The overall incidence rate of nonfatal injuries among children under 5 years old was 16.0 per 1000 population in the prior 12 months. The first three leading causes of non-fatal injuries were falls,animal bite, fire/bum among children under 1 year old,with the rates as 3.9, 1.8 and 1.8 per 1000 population, respectively. For children aged I to 4 years old, the first three leading causes were animal bite, fall, fire/burn with rates as 6.5,6.0 and 2.9 per 1000 population, respectively. 83.0% and 69.0% of last injuries occurred at home for the above said two age groups. No disability was found among children younger than 1 year old who suffered from a nonfatal injury while for the 1-4 age group, the disability accounted for 1.0% of injury-induced outcomes. After adjusting other variables,boys had 1.57 times the risk of injury compared with girls in the 1-4 age group (P＜0.05). The differences on the effects regarding ethmicity,per capita household income, and place were insignificant (P＞0.05). None of the socio-economic variables was found that significantly related to the non-fatal injury risk among children under 1 year old (P＞0.05). Conclusion The incidence of nonfatal injuries among children under 5 years old was 16.0 per 1000 population in the prior 12 months. The three leading causes of injuries were animal bite, falls, fire/bum respectively. Home was the most common place that non-fatal injuries occurred. Boys had a higher risk of injury compared with girls among children aged 1 to 4 years old and the difference was significant.