Studies on Chemoprophylaxis of Trypanosomiasis Using a Competitive Enzyme Immunoassay for the Detection of Isometamidium and Homidium in Cattle and Sheep

This thesis describes studies to improve the ELISA method for determining the concentrations of isometamidium and homidium in the serum of treated animals, and the use of the improved ELISA to monitor drug levels in the field and laboratory. Chapter One is a general review of the relevant literature. Chapter Two describes experiments that were conducted to improve the competitive enzyme immunoassay for the detection of isometamidium in the sera of treated animals. Improvements were required to this assay to reduce inter-sample variation of sera obtained from untreated animals. The use of a new conjugate isometamidium-horseradish-peroxidase produced using the n-hydroxysuccinamide-carbodiimide linkage and modifications to the assay to a sequential saturation competitive enzyme assay, successfully solved the problem of intersample variation. Following the successfull modifications to the isometamidium detection ELISA similar improvements were made to the homidium detection ELISA. Chapter Three describes the use of the new competitive enzyme immunoassay to measure the concentrations of isometamidium in the sera of 35 treated cattle reared under traditional management in a field situation in Zambia. Breakthrough trypanosome infections in the individual cattle were monitored and related to the isometamidium concentration levels at the time of trypanosome detection. One of the 10 breakthrough infections occurred when relatively high drug levels were present and this was taken to indicate that the breakthrough infection may have been drug resistant. The work in this section showed that trypanocide detection ELISAs are a useful tool for determining the drug levels in individual cattle sera and can provide indirect evidence of drug resistant trypanosomes when used in combination with parasitological monitoring methods. Chapter Four describes the evaluation of the prophylactic effect of a slow release device (SRD) containing homidium bromide. The prophylatic effect of this SRD was compared with that of the normal intramuscular (i.m.) injections of isometamidium and homidium bromide. In the SRD group 50 % of the cattle remained protected up to the fourth month after treatment. In the i.m. isometamidium group 50 % of the cattle were protected up to the third month after treatment whereas in the i.m. homidium 50 % remained protected only up to the second month. The levels of isometamidium and ethidium in the serum reflected these differences in the period of prophylaxis. Chapter Five describes an experiment to investigate influence of nutrient intake on the duration of isometamidium prophylaxis in sheep. In this experiment groups of sheep on two planes of nutrition were injected with isometamidium (0.5 mg/kg) and then challenged monthly with bloodstream forms of T. congolense by subcutaneous injection. The concentration of isometamidium in the sera of the animals declined at a similar rate in both groups and was below the lower limit of detection at the time of the breakthrough infections. The mean body weight and serum albumin levels of the animals on the high plane diet was significantly higher than those of the animals on the low plane diet throughout the experiment period. However the mean periods of prophylaxis were very similar in the high plane and low plane diet groups (121 +/- 14 days and 117 +/- 11 days respectively)

Investigating the Soil Quality of Mindolo in Kitwe District

The study sough to investigate the quality of soil in Mindolo area in Kitwe of the Copperbelt province. The main objective of this study is to establish the effects that mining activities have on the soil quality of Mindolo township in Kitwe.  A total of five (5) samples were used for the analysis.  The soil samples were taken to the Copperbelt University laboratory for analysis. To determine the metal concentrates in the soil, Atomic Absorption Spectrometry (AAS) was used. The results of the study were that the soil quality of Mindolo had high alkaline levels due to contamination with heavy metals, which include Fe, Cu, Co, and Pb. Keywords: Soil Quality, Contamination,and the study adopted Atomic Absorption Spectrometry (AAS). DOI: 10.7176/JEP/14-2-02 Publication date: January 31st 202

Trypanosome diversity in wildlife species from the Serengeti and Luangwa Valley ecosystems

<p>Background: The importance of wildlife as reservoirs of African trypanosomes pathogenic to man and livestock is well recognised. While new species of trypanosomes and their variants have been identified in tsetse populations, our knowledge of trypanosome species that are circulating in wildlife populations and their genetic diversity is limited.</p> <p>Methodology/Principal Findings: Molecular phylogenetic methods were used to examine the genetic diversity and species composition of trypanosomes circulating in wildlife from two ecosystems that exhibit high host species diversity: the Serengeti in Tanzania and the Luangwa Valley in Zambia. Phylogenetic relationships were assessed by alignment of partial 18S, 5.8S and 28S trypanosomal nuclear ribosomal DNA array sequences within the Trypanosomatidae and using ITS1, 5.8S and ITS2 for more detailed analysis of the T. vivax clade. In addition to Trypanosoma brucei, T. congolense, T. simiae, T. simiae (Tsavo), T. godfreyi and T. theileri, three variants of T. vivax were identified from three different wildlife species within one ecosystem, including sequences from trypanosomes from a giraffe and a waterbuck that differed from all published sequences and from each other, and did not amplify with conventional primers for T. vivax.</p> <p>Conclusions/Significance: Wildlife carries a wide range of trypanosome species. The failure of the diverse T. vivax in this study to amplify with conventional primers suggests that T. vivax may have been under-diagnosed in Tanzania. Since conventional species-specific primers may not amplify all trypanosomes of interest, the use of ITS PCR primers followed by sequencing is a valuable approach to investigate diversity of trypanosome infections in wildlife; amplification of sequences outside the T. brucei clade raises concerns regarding ITS primer specificity for wildlife samples if sequence confirmation is not also undertaken.</p&gt

Ecological Monitoring and Health Research in Luambe National Park, Zambia: Generation of Baseline Data Layers

Classifying, describing and understanding the natural environment is an important element of studies of human, animal and ecosystem health, and baseline ecological data are commonly lacking in remote environments of the world. Human African trypanosomiasis is an important constraint on human well-being in sub-Saharan Africa, and spillover transmission occurs from the reservoir community of wild mammals. Here we use robust and repeatable methodology to generate baseline datasets on vegetation and mammal density to investigate the ecology of warthogs (Phacochoerus africanus) in the remote Luambe National Park in Zambia, in order to further our understanding of their interactions with tsetse (Glossina spp.) vectors of trypanosomiasis. Fuzzy set theory is used to produce an accurate landcover classification, and distance sampling techniques are applied to obtain species and habitat level density estimates for the most abundant wild mammals. The density of warthog burrows is also estimated and their spatial distribution mapped. The datasets generated provide an accurate baseline to further ecological and epidemiological understanding of disease systems such as trypanosomiasis. This study provides a reliable framework for ecological monitoring of wild mammal densities and vegetation composition in remote, relatively inaccessible environments

Differential Changes in Expression of Intestinal Antimicrobial Peptide Genes During Ascaris lumbricoides Infection in Zambian Adults Do Not Respond to Helminth Eradication

Background. Intestinal helminthiasis modulates immune responses to vaccines and environmental allergens. To explore the impact on intestinal host defense, we assessed expression of antimicrobial peptide genes, together with T cell subset markers and cytokines, in patients with ascariasis before and after treatment

Characterisation of the Wildlife Reservoir Community for Human and Animal Trypanosomiasis in the Luangwa Valley, Zambia

Animal and human trypanosomiasis are constraints to both animal and human health in Sub-Saharan Africa, but there is little recent evidence as to how these parasites circulate in natural hosts in natural ecosystems. A cross-sectional survey of trypanosome prevalence in 418 wildlife hosts was conducted in the Luangwa Valley, Zambia, from 2005 to 2007. The overall prevalence in all species was 13.9%. Infection was significantly more likely to be detected in waterbuck, lion, greater kudu and bushbuck, with a clear pattern apparent of the most important hosts for each trypanosome species. Human infective Trypanosoma brucei rhodesiense parasites were identified for the first time in African buffalo and T. brucei s.l. in leopard. Variation in infection is demonstrated at species level rather than at family or sub-family level. A number of significant risk factors are shown to interact to influence infection rates in wildlife including taxonomy, habitat and blood meal preference. Trypanosoma parasites circulate within a wide and diverse host community in this bio-diverse ecosystem. Consistent land use patterns over the last century have resulted in epidemiological stability, but this may be threatened by the recent influx of people and domesticated livestock into the mid-Luangwa Valley

Immunohaematological reference values for HIV-negative healthy adults in Botswana

BACKGROUND: Clinical laboratories in Botswana have relied entirely on the reference intervals for normal immunohaematological values provided by manufacturers' kits and textbooks. OBJECTIVES: The aim of this study was to determine the means, medians, 2.5th and 97.5th percentile reference intervals, for normal immunohaematological values in healthy adults in Botswana. METHOD: A total of 261 healthy participants comprising 126 men (48%) and 135 (52%) women were enrolled in the southern part of Botswana, and immunological and haematological laboratory parameters were measured. RESULTS: The mean age was 28.8 (95% Confidence Interval [CI] 27.7-29.8) years, with a median of 27 years and a range 18-66 years. The mean haemoglobin level was significantly lower for women (12.4 g/dL; 95% CI 12.1% - 12.7%) than men (15.1 g/dL; 95% CI 14.9% - 15.3%). The women's haemoglobin reference values (9.0 g/dL - 15.0 g/dL) levels were lower than observed in predominantly White populations (12.0 g/dL - 16.0 g/dL), but comparable with regional consensus reference intervals (9.5 g/dL - 15.8 g/dL) recently defined for East and Southern Africa. CONCLUSION: The established values provide an important tool for patient management and could influence decisions on inclusion of participants and adverse events in clinical trials conducted locally

Sleeping sickness and its relationship with development and biodiversity conservation in the Luangwa valley, Zambia

The Luangwa Valley has a long historical association with Human African trypanosomiasis (HAT) and is a recognised geographical focus of this disease. It is also internationally acclaimed for its high biodiversity and contains many valuable habitats. Local inhabitants of the valley have developed sustainable land use systems in co-existence with wildlife over centuries, based on non-livestock keeping practices largely due to the threat from African Animal Trypanosomiasis. Historical epidemics of human sleeping sickness have influenced how and where communities have settled and have had a profound impact on development in the Valley. Historical attempts to control trypanosomiasis have also had a negative impact on conservation of biodiversity. Centralised control over wildlife utilisation has marginalised local communities from managing the wildlife resource. To some extent this has been reversed by the implementation of community based natural resource management programmes in the latter half of the 20th century and the Luangwa Valley provides some of the earliest examples of such programmes. More recently, there has been significant uncontrolled migration of people into the mid-Luangwa Valley driven by pressure on resources in the eastern plateau region, encouragement from local chiefs and economic development in the tourist centre of Mfuwe. This has brought changing land-use patterns, most notably agricultural development through livestock keeping and cotton production. These changes threaten to alter the endemically stable patterns of HAT transmission and could have significant impacts on ecosystem health and ecosystem services. In this paper we review the history of HAT in the context of conservation and development and consider the impacts current changes may have on this complex social-ecological system. We conclude that improved understanding is required to identify specific circumstances where win-win trade-offs can be achieved between the conservation of biodiversity and the reduction of disease in the human population.Ecosystem Services for Poverty Alleviation (ESPA