Mathematical Model as a Tool for the Control of Vector-Borne Diseases: Wolbachia Example

Dengue is a vector-borne disease that risks two-thirds of the world’s population particularly in tropical and subtropical regions. Strategies have been implemented, but they are only effective in the short term. A new innovative and promising strategy against dengue is by the use of Wolbachia bacterium. This requires that Wolbachia-carrying mosquitoes should persist in the population. To assess the persistence of Wolbachia-carrying mosquitoes and its effects on dengue, a number of mathematical models have been formulated and analysed. In this chapter, we review the existing mathematical models of Wolbachia-carrying mosquito population dynamics and dengue with Wolbachia intervention and provide examples of the mathematical models. Simulations of the models are presented to illustrate the model’s solutions

Saving, finance and economic development

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The Public Sector Wage Policy Study

This Policy discusses the growth of public sector employment in Kenya from independence to the early 1990s, highlighting how civil service employment increased by 4.4% annually, while public employment in other sectors grew by 6.4% annually. However, this expansion created a burden on the budget, making it impossible to compensate public servants and provide the necessary resources for service delivery. To address this issue, the Civil Service Reform Programme was implemented in the 1990s, which reduced central government employment to 194,000 by the end of 2003. However, the reduction was not accompanied by an overall wage policy, resulting in distortions in wages between different services and an increase in wage demands since the NARC Government came into power

The effect of Wolbachia on dengue dynamics in the presence of two serotypes of dengue: symmetric and asymmetric epidemiological characteristics

An innovative strategy to reduce dengue transmission uses the bacterium Wolbachia. We analysed the effects of Wolbachia on dengue transmission dynamics in the presence of two serotypes of dengue using a mathematical model, allowing for differences in the epidemiological characteristics of the serotypes. We found that Wolbachia has a greater effect on secondary infections than on primary infections across a range of epidemiological characteristics. If one serotype is more transmissible than the other, it will dominate primary infections and Wolbachia will be less effective at reducing secondary infections of either serotype. Differences in the antibody-dependent enhancement of the two serotypes have considerably less effect on the benefits of Wolbachia than differences in transmission probability. Even if the antibody-dependent enhancement rate is high, Wolbachia is still effective in reducing dengue. Our findings suggest that Wolbachia will be effective in the presence of more than one serotype of dengue; however, a better understanding of serotype-specific differences in transmission probability may be needed to optimize delivery of a Wolbachia intervention

The effect of Wolbachia

An innovative strategy to reduce dengue transmission uses the bacterium <i>Wolbachia</i>. We analysed the effects of <i>Wolbachia</i> on dengue transmission dynamics in the presence of two serotypes of dengue using a mathematical model, allowing for differences in the epidemiological characteristics of the serotypes. We found that <i>Wolbachia</i> has a greater effect on secondary infections than on primary infections across a range of epidemiological characteristics. If one serotype is more transmissible than the other, it will dominate primary infections and <i>Wolbachia</i> will be less effective at reducing secondary infections of either serotype. Differences in the antibody-dependent enhancement of the two serotypes have considerably less effect on the benefits of <i>Wolbachia</i> than differences in transmission probability. Even if the antibody-dependent enhancement rate is high, <i>Wolbachia</i> is still effective in reducing dengue. Our findings suggest that <i>Wolbachia</i> will be effective in the presence of more than one serotype of dengue; however, a better understanding of serotype-specific differences in transmission probability may be needed to optimize delivery of a <i>Wolbachia</i> intervention

Impact of social awareness, case detection, and hospital capacity on dengue eradication in Jakarta: A mathematical model approach

Fumigation is the most popular form of intervention in various parts of the world to combat the spread of dengue fever, including in the city of Jakarta, Indonesia. Various forms of intervention, such as media campaign and case detection, are being carried out to control dengue in Jakarta. This study aims to understand the impact of the media campaign and case detection in controlling dengue spread in the city of Jakarta via a novel mathematical model. The intervention of a media campaign can improve people’s knowledge of dengue, which can make them aware of dengue. Furthermore, we also define our recovery rate as a decreasing function depending on the number of hospitalized individuals. The model was developed as a novel SAEIHR-VW (Susceptible Aware Exposed Infected Hospitalized Recovered - Susceptible and Infected Mosquito) model. Incidence data in Jakarta during 2020 is used to estimate the best-fit parameter of the model. The analysis shows that the disease-free equilibrium is locally asymptotically stable when the basic reproduction number is less than one. The elasticity analysis demonstrates that media campaign intervention is much more sensitive than case detection in suppressing the basic reproduction number. Furthermore, larger case detection does not always provide a better result in reducing the basic reproduction number owing to the quality of treatment in the hospital. The dynamical system sensitivity analysis (local and global) shows that the infection probability rate is the most significant parameter for the infected and hospitalized individuals

Impact of social awareness, case detection, and hospital capacity on dengue eradication in Jakarta: A mathematical model approach

Fumigation is the most popular form of intervention in various parts of the world to combat the spread of dengue fever, including in the city of Jakarta, Indonesia. Various forms of intervention, such as media campaign and case detection, are being carried out to control dengue in Jakarta. This study aims to understand the impact of the media campaign and case detection in controlling dengue spread in the city of Jakarta via a novel mathematical model. The intervention of a media campaign can improve people’s knowledge of dengue, which can make them aware of dengue. Furthermore, we also define our recovery rate as a decreasing function depending on the number of hospitalized individuals. The model was developed as a novel SAEIHR-VW (Susceptible Aware Exposed Infected Hospitalized Recovered - Susceptible and Infected Mosquito) model. Incidence data in Jakarta during 2020 is used to estimate the best-fit parameter of the model. The analysis shows that the disease-free equilibrium is locally asymptotically stable when the basic reproduction number is less than one. The elasticity analysis demonstrates that media campaign intervention is much more sensitive than case detection in suppressing the basic reproduction number. Furthermore, larger case detection does not always provide a better result in reducing the basic reproduction number owing to the quality of treatment in the hospital. The dynamical system sensitivity analysis (local and global) shows that the infection probability rate is the most significant parameter for the infected and hospitalized individuals

Bilateral Huge Ovarian Mature Cystic Teratoma in a Primipara: A Case Report

Background: Mature cystic teratoma (MCT) also known as dermoid cyst is the commonest benign neoplasm of the ovary constituting 10-20% of all the ovarian tumours. They are also the most common ovarian germ cell tumour commonly seen between 20-40 years. They are bilateral in 8-15% of cases. Objective: To report a rare case of bilateral ovarian mature cystic teratoma occurring in a primipara. Methods: The case note of the patient was retrieved, relevant information about the patient, her clinical presentation and management were reviewed. Relevant review of the literature on the subject was also done. Case Report: The patient was a 23 year old primipara (alive) referred from a general hospital. She presented at the gynaecological clinic of Rivers State University Teaching Hospital (RSUTH) with a month history of abdominal distension and lower abdominal pain. There was associated nausea, vomiting and passage of watery stool. There was no history of fever, weight loss, vaginal discharge, urinary frequency or retention of urine. There was generalized abdominal tenderness more marked in the lower abdomen. She had exploratory laparotomy and bilateral ovarian cystectomy. She did well post operatively and was discharged home with a two weeks appointment to the gynaecological clinic. Conclusion: Diagnosis of dermoid cyst is made earlier with pelvic ultrasonography when it is usually small. Unusual finding of a mature huge ovarian cystic teratoma is possible due to delayed presentation for diagnosis and treatment