Spatial analysis of HIV infections in high burden sub-districts in KwaZulu-Natal, South Africa.

Masters Degree. University of KwaZulu-Natal, Durban.Background: Substantial spatial variations in HIV prevalence and incidence at a global, national and district levels have been shown to occur. However, only a few studies have assessed variability of these infections at a highly localised level. Aim: The aim of the study was to assess the spatial variability of HIV prevalence and HIV-1 RNA viral load in two areas within the uMgungundlovu district, KwaZulu-Natal, South Africa. Methods: The data source for this study was from the HIV Incidence Provincial Surveillance System (HIPSS), a multi-stage random sampling of enumeration areas (EAs), households and individuals. From June 2014 to June 2015, HIPSS enrolled 9812 household-representative sample of men and women aged 15-49 years from 221 of the 591 randomly selected EAs. Briefly, the randomly selected households were identified through the global positioning system (GPS) co-ordinates. The head or designate of the selected household was provided with detailed study information, followed by verbal consent, collection of basic sociodemographic information and listing of household members. A single age eligible individual was randomly selected, provided with detailed study information, followed by written informed consent and or assent and enrolled. A questionnaire was administered to obtain demographic, psycho-social and behavioural information, biological samples for laboratory tests and GPS co-ordinates for the household were collected for each enrolled participant at the time of the interview. HIV prevalence, geometric mean viral load and prevalence of viraemia >1000 copies/ml were calculated and mapped per municipal ward using ArcGIS software version 10.3 (ESRI, USA). Micro-geographical cluster detection of HIV prevalence and prevalence of viraemia were performed using Kulldorff spatial scan statistic (SaTScan) at a significance level of p<0.05. Results: Based on the HIV viral load, the overall geometric mean viral load for individuals in the study area was 202 copies /ml, in men it was 735 copies/ml and in women it, was 130 copies /ml. In the south-east of the study area, two high viral load clusters were identified. The first cluster accounted for the overall population and the geometric mean viral load for this cluster was 327 copies/ml. The geometric mean viral load for individuals in the population outside of the high viral load cluster was 125 copies/ml resulting in a geometric mean viral load difference of 202 copies/ml (Log-likelihood ratio =18.95, p=0.001). The second-high viral load cluster accounted for women and the geometric mean viral load for this cluster was 237 copies/ml. The geometric mean viral load for women outside the high viral load cluster was 79 copies/ml and the geometric mean viral load difference was 158 copies/ml (Log-likelihood ratio =18.99, p=0.001). Both the high viral load clusters occurred to the south-east of the study area representing a peri-urban setting. A further analysis of the viral load at a threshold of >1000 copies/ml showed that viral load >1000 copies /ml exceeded 50% in 11 of the 30 Page | 2 municipal wards, and 10 of the 11 wards were located within urban areas. A single cluster was identified and was in the north-west of the study area and approximately over a three kilometre radius having a relative risk of 0.69 (p=0.02). A total of 309 HIV positive individuals contributed to this cluster indicating that 69% or 213 individuals had viral load of 1000 copies/ml. Based on the HIV prevalence analysis, a high-prevalence cluster with a relative risk of 1.75 (p=0.02) was identified in the same north-west area and the HIV prevalence in this area was 71%. Overall men compared to women had higher log10 mean viral load (Log10 mean viral load 3.21 vs 2.62; p<0.001) and higher in the age category15-24 years compared to 25-49 years, (Log10 mean viral load 3.34 vs 2.65; p<0.001). Conclusions: The findings of this study demonstrate that applying spatial analysis to the understanding of HIV epidemiology even in a hyperendemic HIV epidemic setting is a valuable tool to monitor the epidemic. Despite the unprecedented high prevalence of HIV within geographically specific areas, the promising finding of the high prevalence of viral load <1000 copies/ml underscore the importance and impact of HIV programmes that have been rolled-out in this community. Furthermore, the high HIV viral load in young women and men in this region play a significant role in sustaining the epidemic, and there is an urgent need to prioritise interventions critical to reducing the potential for HIV transmission

Modelling drug use: methods to quantify and understand hidden processes

Dynamic modelling is a quantitative technique used by scientists when data are scarce to generate estimates, test hypotheses and forecast trends. This publication explores the potential role of dynamic modelling in helping to interpret data on drug use and its consequences in the European Union. The monograph contains over a dozen expert reviews on modelling techniques and their use in estimating drug use and related health consequences. The publication presents dynamic modelling as a valuable analytical tool, not only in improving insight into drug use, but also in contributing to the development of evidence-based drug policies and interventions

BIG DATA APPLICATIONS AND CHALLENGES IN GISCIENCE (CASE STUDIES: NATURAL DISASTER AND PUBLIC HEALTH CRISIS MANAGEMENT)

This dissertation examines the application and significance of user-generated big data in Geographic Information Science (GIScience), with a focus on managing natural disasters and public health crises. It explores the role of social media data in understanding human-environment interactions and in informing disaster management and public health strategies. A scalable computational framework will be developed to model extensive unstructured geotagged data from social media, facilitating systematic spatiotemporal data analysis.The research investigates how individuals and communities respond to high-impact events like natural disasters and public health emergencies, employing both qualitative and quantitative methods. In particular, it assesses the impact of socio-economic-demographic characteristics and the digital divide on social media engagement during such crises. In addressing the opioid crisis, the dissertation delves into the spatial dynamics of opioid overdose deaths, utilizing Multiscale Geographically Weighted Regression to discern local versus broader-scale determinants. This analysis foregrounds the necessity for targeted public health responses and the importance of localized data in crafting effective interventions, especially within communities that are ethnically diverse and economically disparate. Using Hurricane Irma as a case study, this dissertation analyzes social media activity in Florida in September 2017, leveraging Multiscale Geographically Weighted Regression to explore spatial variations in social media discourse, its correlation with damage severity, and the disproportionate impact on racialized communities. It integrates social media data analysis with political-ecological perspectives and spatial analytical techniques to reveal structural inequalities and political power differentials. The dissertation also tackles the dissemination of false information during the COVID-19 pandemic, examining Twitter activity in the United States from April to July 2020. It identifies misinformation patterns, their origins, and their association with the pandemic\u27s incidence rates. Discourse analysis pinpoints tweets that downplay the pandemic\u27s severity or spread disinformation, while spatial modeling investigates the relationship between social media discourse and disease spread. By concentrating on the experiences of racialized communities, this research aims to highlight and address the environmental and social injustices they face. It contributes empirical and methodological insights into effective policy formulation, with an emphasis on equitable responses to public health emergencies and natural disasters. This dissertation not only provides a nuanced understanding of crisis responses but also advances GIScience research by incorporating social media data into both traditional and critical analytical frameworks

Medical geography in public health and tropical medicine: case studies from Brazil

Within the last few decades, the multitude of infrastructural and environmental changes associated with population growth, human migration, and economic development have catalyzed the emergence and re-emergence of many infectious diseases worldwide. The morbidity and mortality associated with these diseases have in turn led to an increased and renewed impetus to gain a better understanding of the etiology, epidemiology, prevention, and control of these diseases in order to achieve better health and well-being, especially for underprivileged populations. Two traditionally separate fields, medical geography and tropical medicine, have recently seen complex and radical paradigm shifts in response to this global situation: medical geography has been developing many new and sophisticated methods of data collection, data manipulation, and spatial analysis that make it more suited for the study of health-related problems; and tropical medicine has been revisiting the fundamental notion that disease is intimately linked to the physical and cultural geographic environments in which humans live. As a result, concepts of medical geography are being more readily employed within tropical disease research, and tropical medicine is embracing geographic methods as a central mainstay in the control, management, and prevention of tropical diseases. As the associations between these two fields continue to grow, a clearer understanding of how they compliment each other will be needed in order to better define their interrelated roles in augmenting human health. This dissertation examines the multifarious relationships that have developed between the fields of medical geography and tropical medicine in recent years by presenting the reader with a brief history of their common origins and a comprehensive review of the techniques and methodologies in medical geography that are frequently employed in tropical disease research. Following this background information, several case studies are investigated that provide examples of how geographic methods can be easily and effectively employed in the analysis of several tropical diseases, including tungiasis, intestinal helminthes, leprosy, and tuberculosis. These case studies demonstrate some of the advantages and disadvantages of current geographic methods employed in health research, and offer a framework for readers who are interested in applying basic geographic concepts to analyze questions of health

Blood borne infections and duration of injection drug use among young, newly initiated injection drug users

The purpose of this research is to examine select baseline characteristics and drug use and sexual behaviors by duration of injection drug use among young, newly initiated injection drug users (IDUs) to better understand factors associated with risk of infection during the early stage of an injection drug users' career. This research was conducted using questionnaire data from the Collaborative Injection Drug Users Study II (CIDUS-II), a CDC-sponsored prospective study of young (18-29) and/or newly initiated IDUs (duration of injection < 6 years). The study was conducted at six sites in five United States' urban areas: Baltimore, Chicago, Los Angeles, New Orleans, and New York City (Harlem and the Lower East Side). Investigators conducted interviews to assess baseline characteristics and injection drug use and sexual risk factors and obtained serum for testing of bloodborne infections including Hepatitis C (HCV). Duration of injection was calculated from the age of first injection to age at the time of the interview and roughly divided into tertiles by duration while maintaining years as whole numbers: 0-1 year, 2-3 years, and 4-6 years. Among the 1836 participants included in the analysis, 34% (n = 619) had been injecting for 0-1 year, 38% (n = 697) for 2-3 years, and 28% (n = 520) for 4-6 years. Overall HCV prevalence was 34%. By duration of injection, HCV prevalence differed by site of recruitment. In Baltimore for blacks HCV prevalence increased from 33.3% among IDUs injecting <2 years to 79% among IDUs injecting 4-6 years. HCV prevalence in other cities (Chicago, Los Angeles, New Orleans and New York) showed less difference by duration. By racial and ethnic group, HCV prevalence was higher in blacks than non-blacks (=80% white) in all cities (OR = 1.43, 95% CI: 1.00 - 2.05) except Baltimore where prevalence was higher in whites (OR = 5.20, 95% CI: 2.94 - 9.18) than blacks (OR = 2.52, 95% CI: 1.38 - 3.07) as compared to whites in all other cities. The IDU groups of <2 years duration (n = 691) and 2-3 years duration (n = 697) had higher odds than the 4-6 year group (n = 520) of reporting injecting with others (Odds Ratio, OR = 1.52, and OR = 1.47, respectively) and injecting on average more now (OR = 1.44 and OR = 1.44, respectively). The associations remained after multivariate adjustment for demographic variables. In addition, the frequency of several other important risky injection practices were found to be higher among more newly initiated including indirect sharing (sharing of cookers, cotton and rinse water) and backloading, and certain preventive behaviors was found to be lower among this group as well, including use of new needles and NEPs. Duration of injection did not appear to be associated with sexual risk behaviors such as giving or receiving sex for money or drugs or frequency of condom use with sex partners. These data confirm high prevalence of HCV soon after initiation of injection, and increases in HCV prevalence by duration of injection that differed across U.S. cities and by racial/ethnic group. In addition, these data provide support to the ongoing discussions about increased risk among young, newly initiated injection drug users, with risky injection practices higher among more newly initiated IDUs. These findings help to improve our understanding about the periods of increased risk and provide important information about certain baseline characteristics and injection practices among young, newly initiated IDUs -- essential data to consider when developing risk reduction programs

Understanding Zoonotic Enteric Disease in Minnesota: A Spatio Temporal Analysis and Causal Theory Approach

With 75 percent of diseases in humans having origin in animals or animal products, zoonotic diseases have an enormous impact on the global disease burden. A significant portion of this can be attributed to bacterial zoonotic enteric pathogens. This study was designed to locate clusters of bacterial zoonotic enteric outbreaks in the State of Minnesota and study the seasonality of these outbreaks. In addition to identifying hot spots for zoonotic enteric outbreaks in Minnesota, the study also aimed to design a causal model to improve understanding of risk factors. This thesis considered only the bacterial zoonotic pathogens with significant disease burden. Foodborne and non-foodborne zoonotic enteric outbreaks reported by Minnesota Department of Health (MDH) during the period 2000 to 2010 were analyzed in the study. A recent rise in trend of zoonotic enteric disease (ZED) outbreaks were confirmed through empirical analyses. The study also revealed increased bacterial ZED outbreaks in the summer months as compared to other months of the year. Hot spot analysis results indicated twin cities (Minneapolis and St. Paul) as the vulnerable area for ZED outbreaks. The study is especially important for health educators as it shines light on the right places and right time for tailoring interventions to reduce the disease burden

Geographic information system (GIS) and epidemiological associations among foodborne pathogens at the farm

Geographic Information System (GIS), a computer mapping and analysis technology, has emerged as an innovative epidemiological tool in a variety of disciplines. However, the application of GIS to food safety research has received little attention. This study utilized GIS and automated riboprinting technology to examine relationships that existed between animals and their environments, monitoring transmission of pathogens on the farm environment and to nearby surface water environments. A comprehensive epidemiological survey was conducted at The University of Tennessee, Knoxville Experiment Station research dairy farm. More than 40,000 animal and environmental samples were analyzed for Salmonella, Campylobacter jejuni and Escherichia coli 0157:H?. A survey of the Tennessee River, adjacent The University of Tennessee research dairy farm, was also conducted to determine the incidence of these pathogens in the river. Automated riboprinting was used to compare bacterial isolates from various species, locations, and sample types. Salmonella (32%) was the most frequent pathogen isolated on the farm, followed by C. jejuni (21 %) and E. coli 0157:H? (2%). Feed, bedding, water, insects and bird droppings were identified as significant vectors of transmission of pathogens to animals and farm environments. Results of this study indicate that controlling access to animal feed and water sources by insects and wild birds could reduce transmission of pathogens to dairy animals and farm environments. Neither C. jejuni nor E. coli 0157:H? were recovered from the Tennessee River. However, Salmonella was isolated from sampling sites upstream and downstream from the dairy farm. Salmonella was recovered at increased frequency in the Tennessee River at the dairy farm and sites upstream from the farm. Salmonella ser. Senftenberg, Typhimurium, Havana and Newport were the most frequently isolated Serotypes at the dairy farm and from the river. Salmonella ser. Havana, isolated from farm and river water samples, was the only detected serotype showing similar riboprint patterns. Based on pathogens isolated at the farm and not in the river, the variable pattern of Salmonella isolation in the river, and detection of few similar Salmonella serotypes, it was concluded that the dairy farm did not contribute significantly to contamination of the river

SYRINGE AND NEEDLE EXCHANGE PROGRAMS: A VALUABLE HARM REDUCTION TECHNIQUE IN THE BATTLE AGAINST INJECTION DRUG USE

In the last two decades there has been a growing interest surrounding the topic of clean needle exchange programs, the effects they have on injection drug users, their effectiveness in the prevention and spreading of HIV, AIDS and other blood borne pathogens, the cost surrounding the operation of NEPs and SEPs, and their beneficialness on society as a whole. The objective of this research paper is to examine all the aforementioned facets as well as other benefits that stem from NEPs and SEPs. Since injection drug use is driving HIV epidemics in many countries and accounts for almost a third of new infections outside of sub-Saharan Africa, it seems this knowledge is imperative

Geographies of HIV/AIDS in Bangladesh: Vunerability, Stigma and Place.

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