RESUMO
In this work, we formulated and investigated an optimal control problem of the melioidosis epidemic to explain the effectiveness of time-dependent control functions in controlling the spread of the epidemic. The basic reproduction number (R0c) with control measures is obtained, using the next-generation matrix approach and the impact of the controls on R0c is illustrated numerically. The optimal control problem is analyzed using Pontryagin's maximum principle to derive the optimality system. The optimality system is simulated using the forward-backward sweep method based on the fourth-order Runge-Kutta method in the MATLAB program to illustrate the impact of all the possible combinations of the control interventions on the transmission dynamics of the disease. The numerical results indicate that among strategies considered, strategy C is shown to be the most effective in reducing the number of infectious classes compared to both strategy A and strategy B. Furthermore, we carried out a cost-effectiveness analysis to determine the most cost-effective strategy and the result indicated that the strategy B (treatment control strategy) should be recommended to mitigate the spread and impact of the disease regarding the costs of the strategies.
RESUMO
BACKGROUND: Diarrhoea is one of the major contributors to death among under-five children in Ethiopia. Studies conducted in different countries showed that rural children are more severely affected by diarrhoea than urban children. Thus, this study was aimed to identify the socio-demographic, environmental and behavioural associated risk factors of the occurrence of diarrhoea among under-five children in rural Ethiopia. METHODS: Data for the study was drawn from the 2016 Ethiopian Demographic and Health Survey. A total of 8041 under-five children were included in the study. Binary logistic regression was used to assess the association of occurrence of diarrhoea with socio-demographic, environmental and behavioural factors among under-five children. RESULTS: Children aged 6-11 months (AOR:3.5; 95% CI: 2.58-4.87), 12-23 months (AOR: 3.1; 95% CI: 2.33-4.04) and 24-35 months (AOR: 1.7; 95% CI: 1.26-2.34) as compared to > 35 months were significantly associated with an increasing prevalence of diarrhoea. Children in Afar region (AOR: 1.92; 95% CI: 1.01-3.64) and Gambela region (AOR: 2.12; 95% CI: 1.18, 3.81) were significantly associated with an increasing prevalence of diarrhoea, but a decreasing prevalence in Somali region (AOR: .42; 95% CI: (.217-.80) as compared to Tigray region. Increasing prevalence of diarrhoea was also significantly associated with male children (AOR: 1.3; 95% CI: 1.05-1.58); households who shared toilet facilities with other households (AOR: 1.4; 95% CI: 1.09-1.77); fourth birth order (AOR: 1.81; 95% CI: 1.17-2.79), and fifth and above birth order (AOR: 1.85; 95% CI: 1.22, 2.81) as compared to first order; and mother's current age 35-49 years in a household with ≥3 under-five children (AOR: 4.7; 95% CI: 1.64-13.45) as compared to those maternal ages of 15-24 years in a household with ≤2 under-five children. CONCLUSION: The age of a child, sex of a child, region, birth order, toilet facilities shared with other households and the interaction effect of the number of under-five children with mother's current age are identified as associated risk factors for diarrhoea occurrence among under-five children in rural Ethiopia. The findings show the need for planning and implementing appropriate prevention strategies considering these risk factors for rural under-five children.
