Spatial and Temporal Heterogeneity of Malaria Transmission in sub-Saharan Africa

The past decade has seen a marked decline in malaria transmission and substantial progress towards malaria control in parts of Africa. A key tool in malaria control is the insecticide treated net (ITN). However, malaria remains a public health emergency in sub-Saharan Africa with children under five years of age bearing the greatest burden of the disease. In this thesis, I examine three sets of questions that are relevant to the changing epidemiology of malaria. a) I investigated trends in malaria cases in Kilifi County on the Kenyan Coast over geographical area and over time, age, and the effectiveness of ITN use in the community. I observed a decline in the proportion of admitted children who had malaria parasites detected by microscopy from 1998 to 2009 as previously observed in some countries of sub-Saharan African. However, there was a steady and marked increase in the proportion of children with malaria parasites after 2009 accompanied by a shift in burden of disease from younger age groups to older age groups. Community ITN use was highly effective in reducing the risk of malaria. As transmission fell, geographical heterogeneity became more marked. b) I undertook an analysis of data shared from 19 studies conducted between 1996 and 2015 in 7 countries of sub-Saharan Africa to examine whether micro-geographical heterogeneity was generalizable. Hotspots were identified in all datasets, and were more marked at lower transmission intensity. Given the predictability with which hotspots occur as transmission intensity falls, malaria control programmes should have a low threshold for responding to apparent clustering of cases. c) I then considered whether rapid diagnostic tests (RDTs) or PCR would alter detection of hotspots. Using cross-sectional studies of asymptomatic parasitaemia, I describe hotspots of malaria transmission in three sites on the Kenyan Coast using data from 8581 study participants. Microscopy and RDT missed a larger proportion of infections in low transmission settings. PCR hotspots completely overlapped with microscopy hotspots at a moderate transmission, but not at two low transmission setting. From this work, I recommend that malaria control programmes consider PCR testing for targeted control when transmission intensity is low

Challenges Facing the Growth of SMEs in the Furniture Subsector in Nakuru County Town, Kenya

The general objective of the study was to determine the challenges facing the growth of SMEs in the furniture manufacture subsector in Nakuru County town. In order to capture the required information, the study was guided by four specific objectives; which were to determine the effect of technical skills, level of market dynamics knowledge, ownership structure and availability of capital requirements for SMEs growth. The study conducted literature review in order to establish the link with past studies. The study reviewed several models on SMEs growth; stages model, static model, strategic management perspective and stochastic model. The target population under study was the licensed furniture manufacturer SMEs by Nakuru town administration in 2015. In order to realize this purpose, this study adopted descriptive survey employing the use of questionnaires and interviews to collect data from a sample size of 100 entrepreneurs in furniture manufacture in Nakuru town who were selected using stratified random sampling. . Data was analysed using descriptive statistics such as percentages, frequencies tables and figures. Using statistical package for social sciences (SPSS) version 11.0, data was analyzed based on descriptive statistics and Pearson’s Product Moment Correlation Co-efficient was used to establish relationships between independent and dependent variables. The study revealed that there is a positive relationship between technical skills, level of market dynamics knowledge, ownership structure and availability of capital requirements. The positive relationship indicates that there is a correlation between the factors and the Growth of SMEs in Nakuru town. This infers that availability of technical skills has the highest effect on the Growth of SMEs in Nakuru town, followed by lack of managerial skills, then low productivity due to using inefficient technology and availability of capital requirements tailed for SMEs growth. The study recommends that improvement in stakeholder collaboration across the industry by establishing an Industry association, establish a Kenyan Center for Excellence as a platform to provide relevant industry training and co-ordination of R&D. Establish Jua Kali focused marketing entities to facilitate access to formal markets. Key words SME, JUA KALI, Entrepreneu

Effect of Green Logistics Practices on Performance of Supply Chains in Multinational Organizations in Kenya

The purpose for this paper was to explore the effect of green logistics practices on performance of supply chains in multinational organizations. The study was carried on 10 multinational organizations in Kenya, specifically focusing on the following departments; procurement, human resources, environment specialists, and administrators, where the study picked at least four senior officers from each. In developing countries like Kenya green logistic practices in paramount for tomorrow’s energy ingesting. This study did pilot test to ascertain the reliability of the instruments. Objective: The study aimed at findings of remedial measures on performance of supply chain in multinational organizations in Kenya. This resulted to great significance of the study and a replication of the findings in the Kenyan context. The study recommends similar studies to other national organizations so as to validate their outcomes with this study and, then a comparative analysis for future strategies in this area. Keywords: eco design, green purchasing, reverse logistics, responsive packaging and performance of supply chai

Public Health Spending and Health Outcomes in Kenya

Health is important for sustainable economic performance of a country. This study seeks to investigate the effectiveness of public health spending on health outcomes. This is obtained by estimating a health production function for Kenya. In the study, infant mortality rate is used to measure health outcomes. The study uses time series data running from 1984 to 2015. The data is obtained from World Bank database and Kenya National Bureau of Statistics Economic Surveys. Error Correction Model (ECM) is adopted due to presence of cointegration. The results show that public expenditure on average influence health outcomes in Kenya. These results therefore provide evidence to support that increase in public expenditure improves health outcomes. The other factor that is found to be important determinant of health outcomes in Kenya is child immunization. The major policy implication of this study is that Kenyan government should increase budgetary allocation to health sector. In addition, government of Kenya should allocate more resources to child immunization

Maternal and perinatal outcomes in women with eclampsia by mode of delivery at Riley Mother Baby Hospital: A longitudinal case-series study

Background: Eclampsia, considered a serious complication of preeclampsia, remains a life-threatening condition among pregnant women. It accounts for 12% of maternal deaths and 16–31% of perinatal deaths worldwide. Most deaths from eclampsia occurred in resource-limited settings of sub-Saharan Africa. This study was performed to determine the optimum mode of delivery, as well as factors associated with the mode of delivery, in women admitted with eclampsia at Riley Mother and Baby Hospital. Methods: This was a hospital-based longitudinal case-series study conducted at the largest and busiest obstetric unit of the tertiary hospital of western Kenya. Maternal and perinatal variables, such as age, parity, medications, initiation of labour, mode of delivery, admission to the intensive care unit, admission to the newborn care unit, organ injuries, and mortality, were analysed using the Statistical Package for the Social Sciences software version 20.0. Quantitative data were described using frequencies and percentages. The significance of the obtained results was judged at the 5% level. The chi-square test was used for categorical variables, and Fisher’s exact test or the Monte Carlo correction was used for correction of the chi-square test when more than 20% of the cells had an expected count of less than 5. Results: During the study period, 53 patients diagnosed with eclampsia were treated and followed up to 6 weeks postpartum. There was zero maternal mortality; however, perinatal mortality was reported in 9.4%. Parity was statistically associated with an increased odds of adverse perinatal outcomes (p = 0.004, OR = 9.1, 95% CI = 2.0-40.8) and caesarean delivery (p = 0.020, OR = 4.7, 95% CI = 1.3–17.1). In addition, the induction of labour decreased the risk of adverse outcomes (p = 0.232, OR = 0.3, 95% CI = 0.1-2.0). Conclusion: There is no benefit of emergency caesarean section for women with eclampsia. Instead, it increases the risk of perinatal adverse outcomes, including the risk of admission to the newborn unit and perinatal death

Spatiotemporal analysis of insecticide-treated net use for children under 5 in relation to socioeconomic gradients in Central and East Africa

Background: Insecticide-treated net (ITN) use is the core intervention among the strategies against malaria in subSaharan Africa (SSA) and the percentage of ITN ownership has increased from 47% in 2010 to 72% in 2017 across countries in SSA. Regardless of this massive expansion of ITN distribution, considerable gap between ownership and use of ITNs has been reported. Using data from more than 100,000 households in Central and East Africa (CEA) countries, the main aim of this study was to identify barriers associated with low ITN use and conduct geospatial analyses to estimate numbers and locations of vulnerable children living in areas with high malaria and low ITN use. Methods: Main sources of data for this study were the Demographic and Health Surveys and Malaria Indicator Surveys conducted in 11 countries in CEA. Logistic regression models for each country were built to assess the association between ITN ownership or ITN use and several socioeconomic and demographic variables. A density map of children under 5 living in areas at high-risk of malaria and low ITN use was generated to estimate the number of children who are living in these high malaria burden areas. Results: Results obtained suggest that factors such as the number of members in the household, total number of children in the household, education and place of residence can be key factors linked to the use of ITN for protecting children against malaria in CEA. Results from the spatiotemporal analyses found that although total rates of ownership and use of ITNs across CEA have increased up to 70% and 48%, respectively, a large proportion of children under 5 (19,780,678; 23% of total number of children) still lives in high-risk malaria areas with low use of ITNs. Conclusion: The results indicate that despite substantial progress in the distribution of ITNs in CEA, with about 70% of the households having an ITN, several socioeconomic factors have compromised the effectiveness of this control intervention against malaria, and only about 48% of the households protect their children under 5 with ITNs. Increasing the effective ITN use by targeting these factors and the areas where vulnerable children reside can be a core strategy meant to reducing malaria transmission

Dealing with Attrition and Missing Data in Longitudinal Studies: A Critique

Longitudinal studies in teenage pregnancy, like any other topical issue, have been greatly affected by the problem of participant drop out and missing data. Although existing evidence indicate that data from longitudinal studies can provide useful insights regarding individual behaviours; the quality of the data and representativeness of the findings can adversely be compromised by attrition and missing data. Using literature review, this article criticises two papers on teenage pregnancy that have utilised longitudinal data by examining the effectiveness of the measures taken to correct for the attrition and missing data. The article concludes that procedural strategies used to eliminate or reduce attrition and missing data before and during data collection are more effective than employing statistical strategies to deal with the effects afterwards. If statistical procedures have to be used, it is important to first make distinctions of the missing data mechanisms since this has a bearing on whether certain strategies of handling missing data – such as list-wise deletion, pairwise deletion, mean imputation or multiple imputation –will result in biases or not

Investigating the drivers of the spatio-temporal patterns of genetic differences between Plasmodium falciparum malaria infections in Kilifi County, Kenya

Knowledge of how malaria infections spread locally is important both for the design of targeted interventions aiming to interrupt malaria transmission and the design of trials to assess the interventions. A previous analysis of 1602 genotyped Plasmodium falciparum parasites in Kilifi, Kenya collected over 12 years found an interaction between time and geographic distance: the mean number of single nucleotide polymorphism (SNP) differences was lower for pairs of infections which were both a shorter time interval and shorter geographic distance apart. We determine whether the empiric pattern could be reproduced by a simple model, and what mean geographic distances between parent and offspring infections and hypotheses about genotype-specific immunity or a limit on the number of infections would be consistent with the data. We developed an individual-based stochastic simulation model of households, people and infections. We parameterized the model for the total number of infections, and population and household density observed in Kilifi. The acquisition of new infections, mutation, recombination, geographic location and clearance were included. We fit the model to the observed numbers of SNP differences between pairs of parasite genotypes. The patterns observed in the empiric data could be reproduced. Although we cannot rule out genotype-specific immunity or a limit on the number of infections per individual, they are not necessary to account for the observed patterns. The mean geographic distance between parent and offspring malaria infections for the base model was 0.5 km (95% CI 0.3-1.5), for a distribution with 68% of distances shorter than the mean. Very short mean distances did not fit well, but mixtures of distributions were also consistent with the data. For a pathogen which undergoes meiosis in a setting with moderate transmission and a low coverage of infections, analytic methods are limited but an individual-based model can be used with genotyping data to estimate parameter values and investigate hypotheses about underlying processes

A systematic review of changing malaria disease burden in sub-Saharan Africa since 2000: comparing model predictions and empirical observations.

BACKGROUND: The most widely used measures of declining burden of malaria across sub-Saharan Africa are predictions from geospatial models. These models apply spatiotemporal autocorrelations and covariates to parasite prevalence data and then use a function of parasite prevalence to predict clinical malaria incidence. We attempted to assess whether trends in malaria cases, based on local surveillance, were similar to those captured by Malaria Atlas Project (MAP) incidence surfaces. METHODS: We undertook a systematic review (PROSPERO International Prospective Register of Systematic Reviews; ID = CRD42019116834) to identify empirical data on clinical malaria in Africa since 2000, where reports covered at least 5 continuous years. The trends in empirical data were then compared with the trends of time-space matched clinical malaria incidence from MAP using the Spearman rank correlation. The correlations (rho) between changes in empirically observed and modelled estimates of clinical malaria were displayed by forest plots and examined by meta-regression. RESULTS: Sixty-seven articles met our inclusion criteria representing 124 sites from 24 African countries. The single most important factor explaining the correlation between empirical observations and modelled predictions was the slope of empirically observed data over time (rho = - 0.989; 95% CI - 0.998, - 0.939; p < 0.001), i.e. steeper declines were associated with a stronger correlation between empirical observations and modelled predictions. Factors such as quality of study, reported measure of malaria and endemicity were only slightly predictive of such correlations. CONCLUSIONS: In many locations, both local surveillance data and modelled estimates showed declines in malaria burden and hence similar trends. However, there was a weak association between individual surveillance datasets and the modelled predictions where stalling in progress or resurgence of malaria burden was empirically observed. Surveillance data were patchy, indicating a need for improved surveillance to strengthen both empiric reporting and modelled predictions

Effect of transmission intensity on hotspots and micro-epidemiology of malaria in sub-Saharan Africa.

BACKGROUND: Malaria transmission intensity is heterogeneous, complicating the implementation of malaria control interventions. We provide a description of the spatial micro-epidemiology of symptomatic malaria and asymptomatic parasitaemia in multiple sites. METHODS: We assembled data from 19 studies conducted between 1996 and 2015 in seven countries of sub-Saharan Africa with homestead-level geospatial data. Data from each site were used to quantify spatial autocorrelation and examine the temporal stability of hotspots. Parameters from these analyses were examined to identify trends over varying transmission intensity. RESULTS: Significant hotspots of malaria transmission were observed in most years and sites. The risk ratios of malaria within hotspots were highest at low malaria positive fractions (MPFs) and decreased with increasing MPF (p < 0.001). However, statistical significance of hotspots was lowest at extremely low and extremely high MPFs, with a peak in statistical significance at an MPF of ~0.3. In four sites with longitudinal data we noted temporal instability and variable negative correlations between MPF and average age of symptomatic malaria across all sites, suggesting varying degrees of temporal stability. CONCLUSIONS: We observed geographical micro-variation in malaria transmission at sites with a variety of transmission intensities across sub-Saharan Africa. Hotspots are marked at lower transmission intensity, but it becomes difficult to show statistical significance when cases are sparse at very low transmission intensity. Given the predictability with which hotspots occur as transmission intensity falls, malaria control programmes should have a low threshold for responding to apparent clustering of cases