Showing papers by "University of Zimbabwe published in 2000"

Interactions between Aboveground and Belowground Biodiversity in Terrestrial Ecosystems: Patterns, Mechanisms, and Feedbacks

Abstract: Assistant professor in the Department of Biology at Western Washington University, Bellingham, Washington 98225-9160 10: Professor at the Laboratoire d'Ecologie de Sols Tropicaux, ORSTOM/Universite Paris VI, 32 Avenue Henri Varagnat, 93143 Bondy, France 11: Senior scientist at the Centre for Terrestrial Ecology, Netherlands Institute of Ecology, 6666 ZG Heteren, Netherlands Utrecht, Netherlands 12: Professor at the Department of Environmental Studies, University of Utrecht, Utrecht, Netherlands 13: Professor at the Institute of Soil Biology, Academy of Sciences of the Czech Republic, Na sadkach 7, 370 05 Ceske Budejovice, Czech Republic 14: Professor at the Department of Environmental Science, Policy,and Management, University of California, Berkeley, California 94720-3110 15: Professor at the Center for Microbial Ecology, Michigan State University, 540 Plant and Soil Science Building, East Lansing, Michigan 48824-1325 16: Professor at the Department of Animal Ecology, Justus Liebig University of Giessen, Heinrich-Buff-Ring 26-32 (IFZ), D-35392 Giessen, Germany 2: Professor at the Queen Mary and Westfield College, School of Biological Sciences, University of London, London E1 4NS, United Kingdom 3: Research professor and the director of the Centre for Agri-Environmental Research, Department of Agriculture, University of Reading, Earley Gate, Reading RG6 6AT, United Kingdom 4: Professor of Soil Biology and Biological Soil Quality and director of the Department of Environmental Sciences, Wageningen University, 6700 EC Wageningen, Netherlands 5: Professor at the Centre for Biodiversity and Bioresources, School of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia 6: Chair, SCOPE Committee on Soil and Sediment Biodiversity and Ecosystem Functioning, and professor and director, Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, Colorado 80523 7: Scientist at Landcare Research, Lincoln, New Zealand 8: Research professor in the Institute of Ecology at the University of Georgia, 102 Ecology Annex, Athens, Georgia 30602-2360 9: Professor at the Department of Soil Science and Agricultural Engineering, University of Zimbabwe, Mount Pleasant, Harare, Zimbabwe

Impact of HIV infection on meningitis in Harare, Zimbabwe: a prospective study of 406 predominantly adult patients.

Abstract: In Zimbabwe meningitis is among the most serious infections occurring in individuals with HIV infection. In order to determine the causative organisms and characteristics of patients presenting with features of meningitis a prospective cross sectional study was conducted in two tertiary university-affiliated hospitals. 406 predominantly adult (95% were aged 18 years or older) patients were suspected to have meningitis. Overall patients suspected to have meningitis had a high HIV seropositivity irrespective of whether they were later confirmed to have meningitis or not. In addition in-hospital mortality was high irrespective of the cause of meningitis. It is noted that cryptococcal meningitis and tuberculous meningitis have increased as a direct consequence of HIV infection. Findings demonstrate the enormous problem posed by HIV infection and meningitis co-morbidity. Hence appropriate diagnostic procedures especially examination of cerebrospinal fluid are recommended early in individuals presenting with headache even if it is the sole symptom.

Double blind randomised placebo controlled trial of adjunctive prednisolone in the treatment of effusive tuberculous pericarditis in HIV seropositive patients

Abstract: OBJECTIVE—To determine the effect of adjunctive prednisolone on morbidity, pericardial fluid resolution, and mortality in HIV seropositive patients with effusive tuberculous pericarditis. DESIGN—Double blind randomised placebo controlled trial. SETTING—Two medical school affiliated referral hospitals in Harare, Zimbabwe. PATIENTS—58 HIV seropositive patients aged 18-55 years with tuberculous pericarditis. INTERVENTIONS—All patients received standard short course antituberculous chemotherapy and were randomly assigned to receive prednisolone or placebo for six weeks. MAIN OUTCOME MEASURES—Clinical improvement, echocardiographic and radiologic pericardial fluid resolution, and death. RESULTS—29 patients were assigned to prednisolone and 29 to placebo. After 18 months of follow up there were five deaths in the prednisolone treated group and 10 deaths in the placebo group. Mortality was significantly lower in the prednisolone group (log rank χ2 = 8.19, df = 1, p = 0.004). Resolution of raised jugular venous pressure (p = 0.017), hepatomegaly (p = 0.007), and ascites (p = 0.015), and improvement in physical activity (p = 0.02), were significantly more rapid in the prednisolone treated patients. However, there was no difference in the rate of radiologic and echocardiographic resolution of pericardial effusion. CONCLUSIONS—Adjunctive prednisolone for effusive tuberculous pericarditis produced a pronounced reduction in mortality. It is suggested prednisolone should be added to standard short course chemotherapy to treat HIV related effusive tuberculous pericarditis. Keywords: tuberculous pericarditis; HIV infection; echocardiography; prednisolone

Climate change impacts and human settlements in Africa: prospects for adaptation.

Abstract: Climate change impacts on African human settlements arise from a number of climate change-related causes, notably sea level changes, impacts on water resources, extreme weather events, food security, increased health risks from vector home diseases, and temperature-related morbidity in urban environments. Some coastlines and river deltas of Africa have densely populated low-lying areas, which would be affected by a rise in sea level. Other coastal settlements will be subjected to increased coastal erosion. Recent flooding in East Africa highlighted the vulnerability of flood plain settlements and the need to develop adaptive strategies for extreme weather events management and mitigation. In the semi arid and arid zones many settlements are associated with inland drainage water sources. Increases in drought will enhance water supply related vulnerabilities. Inter-basin and international water transfers raise the need for adequate legal frameworks that ensure equity among participating nations. Similarly, water supply and irrigation reservoirs in seasonal river catchments might fail, leading to poor sanitation in urban areas as well as food shortage. Hydroelectric power generation could be restricted in drought periods, and where it is a major contributor to the energy budget, reduced power generation could lead to a multiplicity of other impacts. States are advised to develop other sources of renewable energy. Temperature changes will lead to altered distribution of disease vectors such as mosquitoes, making settlements currently free of vector borne diseases vulnerable. Rapid breeding of the housefly could create a menace associated with enteric disorders, especially in conditions of poor sanitation. The dry savannahs of Africa are projected as possible future food deficit areas. Recurrent crop failures would lead to transmigration into urban areas. Pastoralists are likely to undertake more trans-boundary migrations and probably come into conflict with settled communities. Adaptive measures will involve methods of coastal defences (where applicable), a critical review of the energy sector, both regionally and nationally, a rigorous adherence to city hygiene procedures, an informed agricultural industry that is capable of adapting to changing climate in terms of cropping strategies, and innovations in environment design to maximise human comfort at minimum energy expenditure. In the savannah and arid areas water resource management systems will be needed to optimise water resource use and interstate co-operation where such resources are shared. Climate change issues discussed here raise the need for state support for more research and education in impacts of climate change on human settlements in Africa.

Revisiting Forever Gained: Income Dynamics in the Resettlement Areas of Zimbabwe, 1983-96.

Abstract: This study examines income dynamics for a panel of households resettled on former white‐owned farms in the aftermath of Zimbabwe's independence. There are four core findings: (i) over a 13‐year period (1983–96) there has been an impressive accumulation of assets and a dramatic increase of crop incomes; (ii) the rise of crop incomes is partly due to asset accumulation but largely to increased asset returns; (Hi) differences between households in initial conditions, such as previous farming experience, have few persistent effects; and (iv) income growth has been widely shared, income inequality has fallen sharply and the largest percentage increases in incomes are recorded by households that initially had the lowest incomes.

Intravaginal Practices, Vaginal Flora Disturbances, and Acquisition of Sexually Transmitted Diseases in Zimbabwean Women

Abstract: One hundred sixty-nine Zimbabwean women were studied to determine whether the use of intravaginal practices (cleaning with the fingers, wiping the vagina, and inserting traditional substances) are associated with disturbances of vaginal flora and acquisition of sexually transmitted diseases (STDs). Subjects were interviewed and received counseling and a pelvic examination at enrollment, 1 month, and 6 months, and vaginal specimens were collected at enrollment and at 6 months. Users were more likely than nonusers to have vaginal flora disturbances but were not more likely to acquire an STD (relative risk [RR], 2.15; P=.188). Certain vaginal flora disturbances were associated with increased STD incidence and HIV prevalence. The absence of lactobacilli from the vaginal flora was associated with being positive for human immunodeficiency virus in baseline (odds ratio [OR], 0.24; P=.001) and 6-month transition multivariate models (OR, 0.39; P=.025). The presence of clue cells at baseline was associated with a higher incidence of STDs (RR, 1. 94; P=.025).

HPV-based cervical cancer screening in a population at high risk for HIV infection.

Abstract: We determined the utility of an assay for 13 cancer-associated HPV types in primary cervical cancer screening of Zimbabwe women at high risk of HIV infection. HIV antibody status was determined by ELISA of oral mucosal specimens, and HPV DNA in the genital tract was identified by hybridization of cervical scrapes with probe B of Hybrid Capture II. Among the 466 women investigated, the prevalence of HPV, low-grade squamous intraepithelial lesions (LGSIL) and high-grade SIL (HGSIL) were 47.2%, 13.9% and 12%. Fifty-three and one-half percent of the women were HIV-seropositive. As compared with HIV-seronegative women, HIV-infected women had a greater than 2-fold HPV prevalence (64.3% vs. 27.6%), a greater than 7-fold amount of HPV DNA (RLU of 82.6 vs. 10.7) in HPV(+) women assessed as normal on the reference standard, and a nearly 3-fold greater HGSIL prevalence (17.3% vs. 5.9%). The strong link between HGSIL and HPV DNA positivity was seen in both HIV-infected and HIV-seronegative women. The amount of HPV DNA increased with disease severity in both HIV-seronegative and HIV-infected women. The sensitivity and specificity of the HPV test for HGSIL were, respectively, 90.7% (95% confidence limit 77.9-97.4%) and 41.3% (34.5-48.3%) in HIV-infected women and 61.5% (31.6-86.1%) and 74.5% (68.0-80.3%), respectively, in HIV(-) women. The usefulness of the HPV test as a screening test for cervical cancer in areas of high HPV prevalence will depend upon local health resource availability, disease priorities and policies regarding clinical case management.

Is audio computer-assisted self-interviewing a feasible method of surveying in Zimbabwe?

Abstract: BACKGROUND: Research into reproductive health is dependent on participants accurately reporting sensitive behaviours. We examined whether audio computer-assisted self-interviewing (ACASI), which increased sensitive behaviour reporting in the US, is a feasible method of surveying in developing countries. METHODS: Zimbabwean women in three educational groups were surveyed about demographics and family planning using interviewer and ACASI modes. An exit survey was administered to elicit information about the participants' opinions and experiences using ACASI. RESULTS: The majority of women (86%) preferred ACASI to interviewer mode. The reasons mentioned were always related to increased confidentiality and privacy. Ability to use ACASI and user preferences varied with educational level. More women with primary school or less education (53%) reported problems with computer use than women in the higher educational groups (10-12%). The percentage of women having perfect response concordance between ACASI and interviewer modes increased significantly with education (64%, 81%, and 84% respectively; P(trend) <0.001). CONCLUSIONS: Use of ACASI may be more feasible in Zimbabwe and other developing countries than was originally thought, but ACASI programs should continue to be improved and tested in various countries and population groups

Orally administered, insulin-loaded amidated pectin hydrogel beads sustain plasma concentrations of insulin in streptozotocin-diabetic rats.

Abstract: We report successful oral administration of insulin entrapped in amidated pectin hydrogel beads in streptozotocin (STZ)-diabetic rats, with a concomitant reduction in plasma glucose concentration. The pectin-insulin (PI) beads were prepared by the gelation of humilin-pectin solutions in the presence of calcium. Separate groups of STZ-diabetic rats were orally administered two PI beads (30 micrograms insulin) once or twice daily or three beads (46 micrograms) once daily for 2 weeks. Control non-diabetic and STZ-diabetic rats were orally administered pectin hydrogel drug-free beads. By comparison with control non-diabetic rats, untreated STZ-diabetic rats exhibited significantly low plasma insulin concentration (0.32+/-0. 03 ng/ml, n=6, compared with 2.60+/-0.44 ng/ml in controls, n=6) and increased plasma glucose concentrations (25.84+/-1.44 mmol/l compared with 10.72+/- 0.52 mmol/l in controls). Administration of two PI beads twice daily (60 micrograms active insulin) or three beads (46 micrograms) once a day to STZ-diabetic rats increased plasma insulin concentrations (0.89+/-0.09 ng/ml and 1.85+/- 0.26 ng/ml, respectively), with a concomitant reduction in plasma glucose concentration (15.45+/-1.63 mmol/l and 10.56+/-0.26 mmol/l, respectively). However, a single dose of PI beads (30 micrograms) did not affect plasma insulin concentrations, although plasma glucose concentrations (17.82+/-2.98 mmol/l) were significantly reduced compared with those in untreated STZ-diabetic rats. Pharmacokinetic parameters in STZ-diabetic rats show that the orally administered PI beads (30 micrograms insulin) were more effective in sustaining plasma insulin concentrations than was s.c. insulin (30 micrograms). The data from this study suggest that this insulin-loaded amidated pectin hydrogel bead formulation not only produces sustained release of insulin, but may also reduce plasma glucose concentration in diabetes mellitus.

Delta Scuti Network observations of XX Pyx: detection of 22 pulsation modes and of short-term amplitude and frequency variations

Abstract: We report multisite observations devoted to the main-sequence δ Scuti star XX Pyx, conducted as the 17th run of the Delta Scuti Network. Over 125 nights a total of 550 h of usable time-series photometric B- and V-filter data were acquired involving both photoelectric and CCD measurements at eight observatories spread around the world, which represents the most extensive single time-series for any pulsating star other than the Sun obtained so far. We describe our observations and reduction methods, and present the frequency analysis of our new data. First, we detect six new pulsation and five new combination frequencies in the star's light curves. We also discover evidence for amplitude and/or frequency variations of some of the modes during the observations. These can occur on time-scales as short as 20 d and show quite diverse behaviour. To take them into account in the frequency analysis, a so-called non-linear frequency analysis method was developed, allowing us to quantify the temporal variability of the modes and to compensate for it. Following that we continue the frequency search and we also incorporate published multisite observations. In this way, we reveal three more pulsation and two more combination frequencies. In the end, we report a total of 30 significant frequencies – 22 of which correspond to independent pulsation modes. This is the largest number of independent modes ever detected in the light curves of a δ Scuti star. The frequencies of the modes show preferred separations as already suggested by previous work on this star; they are also arranged in clear patterns. These results lead to a refinement of the stellar mean density and to a new constraint on the rotation rate of XX Pyx (νrot=1.1±0.3 d−1). However, our attempts to identify the modes by pattern recognition failed. Moreover, mode identification from multicolour photometry failed as well because the high pulsation frequencies make this method unfavourable. The diverse behaviour of the amplitude and frequency variations of some of the modes leaves resonances as the only presently known possibility for their explanation.

Communication of the musculocutaneous nerve with the median nerve.

Abstract: Objective To study the frequency of occurrence as well as the course and variations in the communicating branch of the musculocutaneous nerve and the relationship of the communicating branch to other structures in the upper arms of Zimbabwean subjects. Design Cross sectional anatomical dissections. Setting Department of Anatomy,University of Zimbabwe Medical School, Harare, Zimbabwe. Subjects Twenty four upper limbs from twelve preserved cadavers of both sexes. Results Eight instances of communication from musculocutaneous nerve to the median nerve were observed. Bilateral communication was observed in two cadavers. The communicating branch arose either before or after it pierced the coracobrachialis muscle. In one instance the whole musculocutaneous nerve joined the median nerve. In two instances, the musculocutaneous nerve did not pierce the coracobrachialis muscle. In two instances the communicating branch arose after the origin of the muscular branch to the biceps brachii. Conclusions The communicating branch was present in 33% of the cases. The communicating branch when present varied considerably in respect of its origin and its union with the median nerve. In one extreme case, the whole musculocutaneous nerve joined the median nerve and the muscular branches to the biceps brachii and brachilis arose from the median nerve. The clinician or surgeon should be aware of the presence of communicating branch and its variations in origin, course and relationships in the upper arm.

Decomposition and nutrient release from mango and miombo woodland litter in Zimbabwe

Abstract: Litter inputs from trees are potentially important in agroforestry systems as sources of nutrients and organic matter. In the smallholder farming areas of Zimbabwe, litter from trees in natural woodlands (miombo) is applied to croplands as a soil amendment. Soils in smallholder areas are generally sandy and contain low amounts of C, N, P and S. Mango trees are planted widely on smallholder farms, but miombo litter is a preferred soil amendment to mango litter. Leaf litter from mango (Mangifera indica L.) and miombo woodland were assessed as soil amendments through decomposition and nutrient release studies in Zimbabwe. Mass loss was assessed in 7 mm mesh litter bags. Changes in lignin, cellulose, hemicellulose, polyphenols and nutrient release were also assessed. Miombo litter had higher initial concentrations of N, P, S, Mg and lignin, and lower polyphenol contents than mango litter. Mass loss was faster in miombo than mango litter, with miombo litter losing 72% of the initial mass over 18 months in comparison with a 55% mass loss for mango litter under the same conditions. Initial litter N, lignin content, and Lignin–N ratios were correlated strongly with mass loss. The rate of lignin loss was higher in miombo than in mango litter. Total polyphenols could not be detected in either litter type after 2 months. There was less N immobilization in miombo litter than in mango during the 18-month study. Net N mobilization in miombo litter accounted for 66% of the initial nitrogen. N immobilization and release correlated strongly with initial litter N, lignin content and Lignin–N. Miombo litter also released more P and S than mango litter over 18 months. More rapid nutrient release by miombo litter may be the reason for its being a preferred soil amendment to mango litter, but mango litter could be used to maintain or enhance soil C.

Detection of Kaposi's sarcoma-associated herpesvirus in oral and genital secretions of Zimbabwean women.

Abstract: Kaposi's sarcoma-associated herpesvirus (KSHV) in oral and genital secretions of women may be involved in horizontal and vertical transmission in endemic regions. Nested polymerase chain reaction assays were used to detect KSHV DNA sequences in one-third of oral, vaginal, and cervical specimens and in 42% of peripheral blood mononuclear cell (PBMC) specimens collected from 41 women infected with human immunodeficiency virus type 1 who had Kaposi's sarcoma (KS). KSHV DNA was not detected in specimens from 100 women without KS, 9 of whom were seropositive for KSHV. A positive association was observed between KSHV DNA detection in oral and genital mucosa, neither of which was associated with KSHV DNA detection in PBMC. These data suggest that KSHV replicates in preferred anatomic sites at levels independent of PBMC viremia. Detection of genital-tract KSHV only among relatively immunosuppressed women may provide an explanation for infrequent perinatal transmission of KSHV.

Guess who's coming to dinner : Migration from Lesotho, Mozambique and Zimbabwe to South Africa

Abstract: Although a more balanced debate about cross-border migration in South Africa is starting to take place xenophobic stereotypes about migrants of African origin are still all too common. Allusions to a "flood of illegal aliens" who bring disease and crime to the country and who are seen to be a threat to the social and fiscal stability of South Africa are unfortunately still rife in the mainstream press in South Africa. This article is an attempt to challenge some of these stereotypes. Drawing on national surveys recently conducted by the Southern African Migration Project in Lesotho Mozambique and Zimbabwe it will be argued that much of the negative stereotyping around cross-border migration from these three countries in particular in unfounded. A profile of migration histories of those interviewed is followed by a discussion of peoples attitudes towards cross-border movement and immigration policy as well as an analysis of possible future migration trends. The article concludes with a discussion of the policy relevance of the research and makes some general policy recommendations. (authors)