\u3cem\u3eBartonella\u3c/em\u3e Infection in Immunocompromised Hosts: Immunology of Vascular Infection and Vasoproliferation

Most infections by genus Bartonella in immunocompromised patients are caused by B. henselae and B. quintana. Unlike immunocompetent hosts who usually develop milder diseases such as cat scratch disease and trench fever, immunocompromised patients, including those living with HIV/AIDS and posttransplant patients, are more likely to develop different and severe life-threatening disease. This paper will discuss Bartonella\u27s manifestations in immunosuppressed patients and will examine Bartonella\u27s interaction with the immune system including its mechanisms of establishing infection and immune escape. Gaps in current understanding of the immunology of Bartonella infection in immunocompromised hosts will be highlighted

Dynamics of the seasonal floodplain fishery of the Okavango Delta, Botswana

Inland fisheries provide vital proteins, jobs and income, for some of the most marginalized communities of the world. The role of inland fisheries in household food security is particularly important in Africa, where most of the world’ poorest are found. Therefore, there is a compelling need to enhance our understanding of the dynamics of floodplain fisheries because of their intrinsic value to riparian communities. Understanding their impotance will lead to their sustainable utilisation, which will contribute to the attainment of some of the 2030 Sustainable Development Goals. Therefore, this thesis examines the relationship between fish dynamics and environmental variability in flood-pulsed systems, by using the Okavango Delta as a case study. Establishing this relationship is important towards identifying the key drivers of change, restoration and persistence in floodplain fish communities. The thesis also highlights the dynamic interactions between seasonal hydrology and nutrient dynamics in floodplain systems. These dynamic processes, coupled with a heterogeneous system, sustain a diverse fish community that is a key source of livelihoods for the delta’s riparian community. Dynamic processes within the fish community, such as distribution, feeding and growth are driven by the seasonal flood pulse. Currently, the Okavango Delta fishery is managed through a series of classical management approaches which are incompatible with the dynamic nature of floodpulsed systems. The best management approach is through balanced harvesting, which has been inadvertently implemented by traditional exploitation practices. Management interventions in floodplain fisheries should be adaptive, practical, realistic and implementable, which in particular means acceptable to the stakeholders. Most developing countries have limited resources, and these should be spent on achievable and practical activities. Informed management also necessitates continuous long-term monitoring of exploited fisheries to follow changes and to gradually improve our understanding fishing patterns and their impact on the fish communities. This involves the collection of fisheries related data across a broad spectrum of activities (e.g. fish consumption, employment creation, various kinds of biological data on species exploited, gear use and efficiencies, etc.) and associated factors/ variables (e.g. environmental factors, various land-use activities, etc.). Once these have been documented and understood, they can be integrated into a flexible management system, which will allow for more adaptive management of these resources. Such integration is currently lacking in the Okavango Delta and also in floodplain fisheries in general.Doktorgradsavhandlin

Review of Aquatic Biodiversity Dynamics in the Okavango Delta: Resilience in a Highly Fluctuating Environment

Wetlands are key ecosystems of high biological diversity that provide valuable ecosystem services. These are particularly important in water stressed semi-arid countries, which enhances their vulnerability to degradation. The Okavango Delta, a key wetland in Botswana, is characterised by dynamic inter and intra specific interactions. There are dynamic biotic and abiotic interactions in the system that enhances its resilience. The flood pulse is the main factor mediating bio-physical dynamics in this system. Despite the various perturbations that have been experienced in the system, the Delta has always been able to absorb them and retain its character at the general ecosystem level. These notwithstanding, there have been some changes at the local scale where the Delta has shifted regimes and entered into altered states as a consequence of either channel or lagoon failure. Management of these systems should ensure that their dynamic characteristics are maintained, and this is enshrined within the panarchy concept. Adopting the resilience framework in natural resources management allows for flexibility in devising management strategies to respond to future unexpected events

Bartonella

Most infections by genus Bartonella in immunocompromised patients are caused by B. henselae and B. quintana. Unlike immunocompetent hosts who usually develop milder diseases such as cat scratch disease and trench fever, immunocompromised patients, including those living with HIV/AIDS and posttransplant patients, are more likely to develop different and severe life-threatening disease. This paper will discuss Bartonella's manifestations in immunosuppressed patients and will examine Bartonella's interaction with the immune system including its mechanisms of establishing infection and immune escape. Gaps in current understanding of the immunology of Bartonella infection in immunocompromised hosts will be highlighted

Assessing the Information Seeking Behaviour of Researchers at the Okavango Research Institute, Botswana

The Okavango Research Institute (ORI), a branch of the University of Botswana (UB), located in the North Western region of Botswana, serves researchers in the natural and social sciences. ORI researchers need information to support research that contributes towards sustainable use of Botswana’s wetlands, which includes the Okavango Delta and other related wetlands. This study investigated the information seeking behaviour of ORI’s researchers. The aim of the study was to understand how they seek information, the information sources they use, and the problems they encounter when seeking information. Since ORI is a small institution, all the organization’s researchers were included in this study, which used a quantitative research method in the form of a survey. A structured questionnaire was used for data collection. The results showed that researchers in ORI seek information that is closely aligned to their research fields. The majority of researchers seek information to conduct research, write articles for publication, and to update their knowledge. Most of the researchers indicated that they prefer searching the internet and accessing the library remotely to satisfy their information needs. They reported poor internet connectivity, outdated library materials, and lack of time and skills to search for information as some of the challenges to successful information seeking. The study therefore recommends that acquisition of relevant and current information sources in appropriate formats be priortised and that library staff undertake information literacy skills sessions for researchers

Neurobehavioral Effects in HIV-Positive Individuals Receiving Highly Active Antiretroviral Therapy (HAART) in Gaborone, Botswana

Objective To explore the prevalence and features of HIV-associated neurocognitive disorders (HANDS) in Botswana, a sub-Saharan country at the center of the HIV epidemic. Design and Methods A cross sectional study of 60 HIV-positive individuals, all receiving highly active antiretroviral therapy (HAART), and 80 demographically matched HIV-seronegative control subjects. We administered a comprehensive neuropsychological test battery and structured psychiatric interview. The lowest 10th percentile of results achieved by control subjects was used to define the lower limit of normal performance on cognitive measures. Subjects who scored abnormal on three or more measures were classified as cognitively impaired. To determine the clinical significance of any cognitive impairment, we assessed medication adherence, employment, and independence in activities of daily living (ADL). Results HIV+ subjects were impaired for all cognitive-motor ability areas compared with matched, uninfected control subjects. Thirty seven percent of HIV+ patients met criteria for cognitive impairment. Conclusion These findings indicate that neurocognitive impairment is likely to be an important feature of HIV infection in resource-limited countries; underscoring the need to develop effective treatments for subjects with, or at risk of developing, cognitive impairment

Extraction of Pesticides from Plants using Solid Phase Microextraction and QuEChERS

A study employing dispersive solid phase extraction in the formof the quick, easy, cheap, effective, rugged and safe (QuEChERS) method and solid phase microextraction (SPME) for the cleanup of pesticides in plant samples from the Okavango Delta (Botswana) is presented. Concentration levels of aldrin, 1,1-dichloro-2,4-bis[chlorophenyl]ethane (DDD), 1,1-dichloro- 2,2-bis[p-chlorophenyl]ethylene(DDE), 1,1,1-trichloro-2,2-bis[p-chlorophenyl]ethane (DDT), dieldrin, endosulfan and endrin were investigated using gas chromatography with electron capture detection (GC-ECD) and confirmedwith gas chromatography with high resolution time of flight mass spectrometry (GC-TOFMS). Parameters affecting the extraction efficiencies of both techniques were optimized. In the absence of CRMs for the plants under investigation, method validation and evaluation of the extraction efficiencies were achieved through spiking of Nymphaea nouchali (Tswii) leaves at two concentration levels with trichlorobenzene as an internal standard. Recoveries for both SPME and QuEChERS were in the range 61–95 %. The calibration plots were reproducible and linear (R2>0.995) with limits of detection ranging from 0.102 to 1.693 μg L–1 for all the pesticides. The optimal conditions for QuEChERS and SPME were applied to the extraction of pesticides residues from the edible parts (leaves, roots and/ or stems) of Asparagus africanus, Cleome hirta and Nymphaea nouchali plants. No pesticides were detected in the leaves and stems of all the plants studied. Aldrin and endosulfan were detected in the Nymphaea nouchali roots at concentrations of 3–21 μg kg–1 and 5–3 μg kg–1, respectively. Pentachlorobenzene (PCB) and hexachlorobenzene (HCB) were also detected but were not quantified.KEYWORDS Gas chromatography, mass spectrometry, pesticide, plant sample, green techniques

Neurocognitive impairment among HIV-positive individuals in Botswana: a pilot study

<p>Abstract</p> <p>Background</p> <p>The primary objective of this study was to determine the prevalence of neurocognitive impairment among HIV-positive individuals in Botswana, using the International HIV Dementia Scale (IHDS). We also compared performance on the IHDS with performance on tests of verbal learning/memory and processing speed, and investigated the association between performance on the IHDS and such variables as depression, age, level of education and CD4 count.</p> <p>Methods</p> <p>We conducted a cross-sectional study of 120 HIV-positive individuals randomly selected from an outpatient HIV clinic in Gaborone, Botswana. Patients provided a detailed clinical history and underwent neuropsychological testing; measures of depression, daily activities and subjective cognitive complaints were recorded.</p> <p>Results</p> <p>Despite the fact that 97.5% of subjects were receiving highly active antiretroviral therapy (HAART), 38% met criteria for dementia on the IHDS, and 24% were diagnosed with major depressive disorder. There was a significant association between neurocognitive impairment as measured by the IHDS and performance on the other two cognitive measures of verbal learning/memory and processing speed. Level of education significantly affected performance on all three cognitive measures, and age affected processing speed and performance on the IHDS. Depression and current CD4 count did not affect performance on any of the cognitive measures.</p> <p>Conclusions</p> <p>The prevalence of neurocognitive impairment in HIV-positive individuals in Botswana is higher than expected, especially since almost all of the subjects in this study were prescribed HAART. This suggests the need to reconsider the timing of introduction of antiretroviral therapy in developing countries where HAART is generally not administered until the CD4 cell count has dropped to 200/mm³or below. The contribution of other factors should also be considered, such as poor central nervous system penetration of some antiretrovirals, drug resistance, potential neurotoxicity, and co-morbidities. Memory impairment and poor judgment may be underlying causes for behaviours that contribute to the spread of HIV and to poor adherence. It is important to identify these neurobehavioural complications of HIV so that effective treatments can be developed.</p

Healthcare professionals' knowledge of modifiable stroke risk factors: A cross-sectional questionnaire survey in greater Gaborone, Botswana

Background - Stroke remains the second leading cause of deaths and disability globally, with highest mortality in Africa (low- and middle-income countries). It is crucial for healthcare professionals to have sufficient stroke risk factors' knowledge in order to reduce the stroke burden. Aims - We investigated healthcare professionals' knowledge of modifiable stroke risk factors, and identified demographic factors influencing this knowledge. Methods - In this cross-sectional survey study from Botswana (upper middle-income country), structured questionnaires reflecting recent stroke guidelines were administered to a representative selection of healthcare workers in greater Gaborone. The response rate was 61.4%, comprising 84 doctors, 227 nurses and 33 paramedics. Categorical data were described using percentages and Chi-square tests. Associations between stroke risk factors' knowledge and demographic factors were analyzed with one-way ANOVA using SPSS 25 statistical software. Results - Awareness rate of individual stroke risk factors was highest for hypertension (96.5%), followed by obesity (93.3%), smoking (91.9%), elevated total cholesterol (91.0%), physical inactivity (83.4%), elevated low-density lipoprotein (LDL) cholesterol (81.1%), excessive alcohol drinking (77.0%), and lowest for diabetes (73.3%). For all-8 risk factors, doctors had the highest knowledge, followed by nurses and paramedics lowest (7.11 vs 6.85 vs 6.06, P < 0.05)

How applicable is the single-dose AMBITION regimen for HIV-associated cryptococcal meningitis to high-income settings?

The AMBITION-cm phase III randomized controlled trial, conducted in east and southern Africa, showed that a single high dose (10 mg/kg) of liposomal amphotericin B, given with an optimized oral backbone of fluconazole and flucytosine, was non-inferior to the World Health Organization (WHO)-recommended regimen of seven days of amphotericin B deoxycholate plus flucytosine for treatment of HIV-associated cryptococcal meningitis, and has been incorporated into updated WHO treatment guidelines. We believe the trial findings also have important implications for the treatment of HIV-associated cryptococcal meningitis in high-income settings. We advance the arguments, supported by evidence where available, that the AMBITION-cm study regimen is likely to be (i) as fungicidal as the currently recommended 14-day liposomal amphotericin based treatments, (ii) better tolerated with fewer adverse effects, and (iii) confer significant economic and practical benefits, therefore should be included as a treatment option in guidance for HIV-associated cryptococcal treatment in high-income country settings