Showing papers by "University of Zimbabwe published in 2008"

Validation of the alcohol, smoking and substance involvement screening test (ASSIST)

Abstract: Aim The concurrent, construct and discriminative validity of the World Health Organization's Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) were examined in a multi-site international study. Participants One thousand and 47 participants, recruited from drug treatment (n = 350) and primary health care (PHC) settings (n = 697), were administered a battery of instruments. Measurements Measures included the ASSIST; the Addiction Severity Index-Lite (ASI-Lite); the Severity of Dependence Scale (SDS); the MINI International Neuropsychiatric Interview (MINI-Plus); the Rating of Injection Site Condition (RISC); the Drug Abuse Screening Test (DAST); the Alcohol Use Disorders Identification Test (AUDIT); the Revised Fagerstrom Tolerance Questionnaire (RTQ); and the Maudsley Addiction Profile (MAP). Findings Concurrent validity was demonstrated by significant correlations between ASSIST scores and scores from the ASI-Lite (r = 0.76–0.88), SDS (r = 0.59), AUDIT (r = 0.82) and RTQ (r = 0.78); and significantly greater ASSIST scores for those with MINI-Plus diagnoses of abuse or dependence (P < 0.001). Construct validity was established by significant correlations between ASSIST scores and measures of risk factors for the development of drug and alcohol problems (r = 0.48–0.76). Discriminative validity was established by the capacity of the ASSIST to discriminate between substance use, abuse and dependence. Receiver operating characteristic (ROC) analysis was used to establish cut-off scores with suitable specificities (50–96%) and sensitivities (54–97%) for most substances. Conclusions The findings demonstrated that the ASSIST is a valid screening test for identifying psychoactive substance use in individuals who use a number of substances and have varying degrees of substance use.

Dietary Patterns and the Risk of Acute Myocardial Infarction in 52 Countries Results of the INTERHEART Study

Abstract: Background— Diet is a major modifiable risk factor for cardiovascular disease, but it varies markedly in different regions of the world. The objectives of the present study were to assess the association between dietary patterns and acute myocardial infarction (AMI) globally. Methods and Results— INTERHEART is a standardized case-control study involving participants from 52 countries. The present analysis included 5761 cases and 10 646 control subjects. We identified 3 major dietary patterns using factor analysis: Oriental (high intake of tofu and soy and other sauces), Western (high in fried foods, salty snacks, eggs, and meat), and prudent (high in fruit and vegetables). We observed an inverse association between the prudent pattern and AMI, with higher levels being protective. Compared with the first quartile, the adjusted ORs were 0.78 (95% CI 0.69 to 0.88) for the second quartile, 0.66 (95% CI 0.59 to 0.75) for the third, and 0.70 (95% CI 0.61 to 0.80) for the fourth (P for trend <0.001). The Western...

Trichomonas vaginalis Infection and Human Immunodeficiency Virus Acquisition in African Women

Abstract: Trichomoniasis vaginalis is the most common nonviral sexually transmitted infection (STI) worldwide with a particularly high prevalence in regions of human immunodeficiency virus (HIV) endemicity. However its impact as a cofactor for HIV acquisition is poorly understood. Samples from 213 women who experienced HIV seroconversion (cases) during a longitudinal study involving 4450 women in Uganda and Zimbabwe were matched with samples from HIV-uninfected women (controls). All samples underwent polymerase chain reaction (PCR) analysis for Trichomonas vaginalis DNA. For cases analyzed samples were from the visit in which HIV seroconversion was detected and the visit preceding detection of seroconversion; for controls one analyzed sample was from the visit matched by follow-up duration to the cases seroconversion visit and the other sample was from the visit immediately preceding the matched visit. The prevalence of T. vaginalis infection before HIV infection was 11.3% in cases and 4.5% in controls (P = .002). In multivariable analysis controlling for hormonal contraception other STIs behavioral and demographic factors the adjusted odds ratio for HIV acquisition was 2.74 (95% confidence interval 1.25-6.00) for T. vaginalis-positive cases. The presence of behavioral risk factors for HIV infection study recruitment from a referral population at high-risk for HIV primary sex partner-associated risk for HIV infection and herpes simplex virus type 2 seropositivity were also predictive of incident HIV infection. T. vaginalis infection is strongly associated with an increased risk for HIV infection in this general population of African women. Given the high prevalence of T. vaginalis infection in HIV-endemic areas T. vaginalis control may have a substantial impact on preventing HIV acquisition among women. (authors)

Energy production from agricultural residues: High methane yields in pilot-scale two-stage anaerobic digestion

Abstract: There is a large, unutilised energy potential in agricultural waste fractions. In this pilot-scale study, the efficiency of a simple two-stage anaerobic digestion process was investigated for stabilisation and biomethanation of solid potato waste and sugar beet leaves, both separately and in co-digestion. A good phase separation between hydrolysis/acidification and methanogenesis was achieved, as indicated by the high carbon dioxide production, high volatile fatty acid concentration and low pH in the acidogenic reactors. Digestion of the individual substrates gave gross energy yields of 2.1–3.4 kWh/kg VS in the form of methane. Co-digestion, however, gave up to 60% higher methane yield, indicating that co-digestion resulted in improved methane production due to the positive synergism established in the digestion liquor. The integrity of the methane filters (MFs) was maintained throughout the period of operation, producing biogas with 60–78% methane content. A stable effluent pH showed that the methanogenic reactors had good ability to withstand the variations in load and volatile fatty acid concentrations that occurred in the two-stage process. The results of this pilot-scale study show that the two-stage anaerobic digestion system is suitable for effective conversion of semi-solid agricultural residues as potato waste and sugar beet leaves.

High prevalence of the CYP2B6 516G→T(*6) variant and effect on the population pharmacokinetics of efavirenz in HIV/AIDS outpatients in Zimbabwe

Abstract: The study sought to investigate the relationship between efavirenz exposure and the CYP2B6 516G→T(*6) genotype in HIV/AIDS outpatients, using pharmacokinetic modelling and simulation. Blood samples where obtained from 74 outpatients treated with a combination regimen including 600 mg efavirenz daily for a duration of at least 3 weeks at clinics in Harare, Zimbabwe. The subjects were genotyped for the major CYP2B6 variant, CYP2B6*6, associated with reduced enzyme activity, using a PCR-RFLP method. Efavirenz plasma concentrations were determined by HPLC-UV. Population pharmacokinetic modelling and simulation of the data were performed in NONMEM VI. A high allele frequency of the CYP2B6*6 allele of 49% was observed. Efavirenz plasma concentrations were above 4 mg/L in 50% of the patients. Genotype and sex were identified as predictive covariates of efavirenz disposition. Pharmacokinetic parameter estimates indicate that a dose reduction to 400 mg efavirenz per day is possible in patients homozygous for the CYP2B6*6 genotype without compromising therapeutic efficacy. The CYP2B6*6 allele occurs at a high frequency in people of African origin and is associated with high efavirenz concentrations. Simulations indicate that an a priori 35% dose reduction in homozygous CYP2B6*6 patients would maintain drug exposure within the therapeutic range in this group of patients. Our preliminary results suggest the conduct of a prospective clinical dose optimization study to evaluate the utility of genotype-driven dose adjustment in this population.

Assessing HIV/AIDS Stigma and Discrimination in Developing Countries

Abstract: HIV/AIDS-related stigma and discrimination are barriers to HIV prevention effectiveness, voluntary counseling and testing uptake, and accessing care in many international settings. Most published stigma scales are not comprehensive and have been primarily tested in developed countries. We sought to draw on existing literature to develop a scale with strong psychometric properties that could easily be used in developing countries. From 82 compiled questions, we tested a 50-item scale which yielded 3 dimensions with 22 items in pilot testing in rural northern Thailand (n = 200) and urban and peri-urban Zimbabwe (n = 221). The three factors (shame, blame and social isolation; perceived discrimination; equity) had high internal consistency reliability and good divergent validity in both research settings. Systematic and significant differences in stigmatizing attitudes were found across countries, with few differences by age or sex noted within sites. This short, comprehensive and standardized measure can be easily incorporated into questionnaires in international research settings.

Multiple benefits of manure: The key to maintenance of soil fertility and restoration of depleted sandy soils on African smallholder farms

Abstract: Manure is a key nutrient resource on smallholder farms in the tropics, especially on poorly buffered sandy soils, due to its multiple benefits for soil fertility. Farmers preferentially apply manure to fields closest to homesteads (homefields), which are more fertile than fields further away (outfields). A three-year experiment was established on homefields and outfields on sandy and clayey soils to assess the effects of mineral nitrogen (N) fertilizer application in combination with manure or mineral phosphorus (P) on maize yields and soil chemical properties. Significant maize responses to application of N and manure were observed on all fields except the depleted sandy outfield. Large amounts of manure (17 t ha−1 year−1) were required to significantly increase soil organic carbon (SOC), pH, available P, and base saturation, and restore productivity of the depleted sandy outfield. Sole N as ammonium nitrate (100 kg N ha−1) or in combination with single superphosphate led to acidification of the sandy soils, with a decrease of up to 0.8 pH units after three seasons. In a greenhouse experiment, N and calcium (Ca) were identified as deficient in the sandy homefield, while N, P, Ca, and zinc (Zn) were deficient or low on the sandy outfield. The deficiencies of Ca and Zn were alleviated by the addition of manure. This study highlights the essential role of manure in sustaining and replenishing soil fertility on smallholder farms through its multiple effects, although it should be used in combination with N mineral fertilizers due to its low capacity to supply N.

Improved HIV-1 incidence estimates using the BED capture enzyme immunoassay.

Abstract: OBJECTIVE: To validate the BED capture enzyme immunoassay for HIV-1 subtype C and to derive adjustments facilitating estimation of HIV-1 incidence from cross-sectional surveys. DESIGN: Laboratory analysis of archived plasma samples collected in Zimbabwe. METHODS: Serial plasma samples from 85 women who seroconverted to HIV-1 during the postpartum year were assayed by BED and used to estimate the window period between seroconversion and the attainment of a specified BED absorbance. HIV-1 incidences for the year prior to recruitment and for the postpartum year were calculated by applying the BED technique to HIV-1-positive samples collected at baseline and at 12 months. RESULTS: The mean window for an absorbance cut-off of 0.8 was 187 days. Among women who were HIV-1 positive at baseline and retested at 12 months, a proportion (epsilon) 5.2% (142/2749) had a BED absorbance < 0.8 at 12 months and were falsely identified as recent seroconverters. Consequently, the estimated BED annual incidence at 12 months postpartum (7.6%) was 2.2 times the contemporary prospective estimate. BED incidence adjusted for epsilon was 3.5% [95% confidence interval (CI), 2.6-4.5], close to the 3.4% estimated prospectively. Adjusted BED incidence at baseline was 6.0% (95% CI, 5.2-6.9) and, like the prospective estimates, declined with maternal age. Unadjusted BED incidence estimates were largely independent of age; the pooled estimate was 58% higher than adjusted incidence. CONCLUSION: The BED method can be used in an African setting, but further estimates of epsilon and of the window period are required, using large samples in a variety of circumstances, before its general utility can be gauged.

Severe Renal Dysfunction and Risk Factors Associated with Renal Impairment in HIV-Infected Adults in Africa Initiating Antiretroviral Therapy

Abstract: BACKGROUND: We sought to investigate renal function in previously untreated symptomatic human immunodeficiency virus (HIV)-infected adults with CD4(+) cell counts of or =60 but or =30 but <60 mL/min/1.73 m(2)) impairments in eGFR. First-line ART regimens included zidovudine-lamivudine plus tenofovir disoproxil fumarate (for 74% of patients), nevirapine (16%), and abacavir (9%) (mostly nonrandomized allocation). After ART initiation, the median eGFR was 89-91 mL/min/1.73 m(2) for the period from week 4 through week 96. Fifty-two participants (1.6%) developed severe reductions in eGFR by week 96; there was no statistically significant difference between these patients and others with respect to first-line ART regimen received (P = .94). Lower baseline eGFR or hemoglobin level, lower body mass index, younger age, higher baseline CD4(+) cell count, and female sex were associated with greater increases in eGFR over baseline, with small but statistically significant differences between regimens (P < .001 for all). CONCLUSIONS: Despite screening, mild-to-moderate baseline renal impairment was relatively common, but these participants had greatest increases in eGFR after starting ART. Severe eGFR impairment was infrequent regardless of ART regimen and was generally related to intercurrent disease. Differences between ART regimens with respect to changes in eGFR through 96 weeks were of marginal clinical relevance, but investigating longer-term nephrotoxicity remains important.

Project Accept (HPTN 043): a community-based intervention to reduce HIV incidence in populations at risk for HIV in sub-Saharan Africa and Thailand.

Abstract: Conclusions: The provision of mobile services, combined with appropriate support activities, may have significant effects on utilization of voluntary counseling and testing. These findings also provide early support for community mobilization as a strategy for increasing testing rates.

Estimating incidence from prevalence in generalised HIV epidemics: methods and validation.

Abstract: Background HIV surveillance of generalised epidemics in Africa primarily relies on prevalence at antenatal clinics, but estimates of incidence in the general population would be more useful. Repeated cross-sectional measures of HIV prevalence are now becoming available for general populations in many countries, and we aim to develop and validate methods that use these data to estimate HIV incidence. Methods and Findings Two methods were developed that decompose observed changes in prevalence between two serosurveys into the contributions of new infections and mortality. Method 1 uses cohort mortality rates, and method 2 uses information on survival after infection. The performance of these two methods was assessed using simulated data from a mathematical model and actual data from three community-based cohort studies in Africa. Comparison with simulated data indicated that these methods can accurately estimates incidence rates and changes in incidence in a variety of epidemic conditions. Method 1 is simple to implement but relies on locally appropriate mortality data, whilst method 2 can make use of the same survival distribution in a wide range of scenarios. The estimates from both methods are within the 95% confidence intervals of almost all actual measurements of HIV incidence in adults and young people, and the patterns of incidence over age are correctly captured.

Bacterial vaginosis and vaginal yeast, but not vaginal cleansing, increase HIV-1 acquisition in African women.

Abstract: Objective To evaluate interrelationships between bacterial vaginosis (BV), vaginal yeast, vaginal practices (cleansing and drying/tightening), mucosal inflammation, and HIV acquisition. Methods A multicenter, prospective, observational cohort study was conducted, enrolling 4531 HIV-negative women aged 18 to 35 years attending family planning clinics in Zimbabwe and Uganda. Participants were tested for HIV and reproductive tract infections and were interviewed about vaginal practices every 3 months for 15 to 24 months. BV was measured by Gram stain Nugent scoring, vaginal yeast by wet mount, and mucosal inflammation by white blood cells on Gram stain. Results HIV incidence was 4.12 and 1.53 per 100 woman-years of follow-up in Zimbabwe and Uganda, respectively (a total of 213 incident infections). Women with BV or vaginal yeast were more likely to acquire HIV, especially if the condition was present at the same visit as the new HIV infection and the visit preceding it (hazard ratio [HR] = 2.50, 95% confidence interval [CI]: 1.68 to 3.72 and HR = 2.97, 95% CI: 1.67 to 5.28 for BV and yeast, respectively). These relationships did not seem to be mediated by mucosal inflammation. Vaginal drying/tightening was associated with HIV acquisition in univariate (HR = 1.49, 95% CI: 1.03 to 2.15) but not multivariate models. Vaginal cleansing was not associated with HIV acquisition. Conclusions BV and yeast may contribute more to the HIV epidemic than previously thought.

Comprehensive analysis and differentiated assessment of food safety control systems: a diagnostic instrument

Abstract: In this article, an instrument is presented to diagnose microbial safety control activities in a food safety management system. The need of such a tool is derived from the importance of microbial safety control and the need for improvement of existing control systems. Careful diagnosis of these systems provides the basis for their improvement. The diagnostic instrument provides a comprehensive checklist of crucial control activities, addressing major technology-dependent and managerial activities in design and operation of preventive measures, intervention processes, and monitoring systems. Secondly, it provides detailed grids describing three levels of execution for each safety control activity to enable a differentiated assessment of ones food safety control system situation. The basic assumption underlying the diagnostic instrument is that activities on a higher level are more predictable and better able to achieve a desired safety outcome, due to more insight in underlying mechanisms and more accurate information. Finally, we discuss that using the instrument may contribute in finding effective types and levels of control activities within given contextual dependencies.

Pyrethroid resistance in the major malaria vector Anopheles arabiensis from Gwave, a malaria-endemic area in Zimbabwe.

Abstract: Background Insecticide resistance can present a major obstacle to malaria control programmes. Following the recent detection of DDT resistance in Anopheles arabiensis in Gokwe, Zimbabwe, the underlying resistance mechanisms in this population were studied.

The Regai Dzive Shiri Project: a cluster randomised controlled trial to determine the effectiveness of a multi-component community-based HIV prevention intervention for rural youth in Zimbabwe – study design and baseline results

Abstract: OBJECTIVE To assess the effectiveness of a community-based HIV prevention intervention for adolescents in terms of its impact on (1) HIV and Herpes simplex virus type 2 (HSV-2) incidence and on rates of unintended pregnancy and (2) reported sexual behaviour, knowledge and attitudes. METHODS Cluster randomised trial of a multi-component HIV prevention intervention for adolescents based in rural Zimbabwe. Thirty communities were selected and randomised in 2003 to early or deferred intervention implementation. A baseline bio-behavioural survey was conducted among 6791 secondary school pupils (86% of eligibles) prior to intervention implementation. RESULTS Baseline prevalences were 0.8% (95% CI: 0.6-1.0) for HIV and 0.2% (95% CI: 0.1-0.3%) for HSV-2. Four girls (0.12%) were pregnant. There was excellent balance between study arms. Orphans who made up 35% of the cohort were at increased risk of HIV [age-sex adjusted odds ratio 3.4 (95% CI: 1.7-6.5)]. 11.9% of young men and 2.9% of young women reported that they were sexually active (P < 0.001); however, there were inconsistencies in the sexual behaviour data. Girls were less likely to know about reproductive health issues than boys (P < 0.001) and were less likely to have used and to be able to access condoms (P < 0.001). CONCLUSION This is one of the first rigorous evaluations of a community-based HIV prevention intervention for young people in southern Africa. The low rates of HIV suggest that the intervention was started before this population became sexually active. Inconsistency and under-reporting of sexual behaviour re-emphasise the importance of using externally validated measures of sexual risk reduction in behavioural intervention studies.

Female genital schistosomiasis – a differential diagnosis to sexually transmitted disease: genital itch and vaginal discharge as indicators of genital Schistosoma haematobium morbidity in a cross‐sectional study in endemic rural Zimbabwe

Abstract: OBJECTIVE To examine the association between schistosomiasis and reproductive tract symptoms. METHOD A cross-sectional study was conducted in a Schistosoma haematobium-endemic area of rural Zimbabwe. A total of 483 permanently resident adult women of Mupfure Ward aged 20-49 were interviewed and examined clinically, each providing three consecutive urine samples. Logistic regression analysis was used to control for sexually transmitted diseases (STDs). RESULTS Women with genital sandy patches had significantly more genital itch (P = 0.009) and perceived their discharge as abnormal (P = 0.003). Eighty percent of the women who had genital itch, yellow discharge, and childhood or current waterbody contact had sandy patches. Fifty-two percent of the women with genital sandy patches did not have detectable S. haematobium ova in urine. Genital schistosomiasis was associated with stress incontinence and pollakisuria, but not with menstrual irregularities, current or previous ulcers, or tumours. CONCLUSION Genital schistosomiasis may be a differential diagnosis to the STDs in women who have been exposed to fresh water in endemic areas. Because of the chronic nature of the disease in adults, we suggest to pay special attention to the prevention of morbidity.

The burden of polyparasitism among primary schoolchildren in rural and farming areas in Zimbabwe.

Abstract: A cross-sectional study was conducted in Zimbabwe among 1303 primary schoolchildren from a rural (53.3%) and a commercial farming area (46.7%) to determine the prevalence of co-infection by helminths and Plasmodium falciparum. Urine was examined on three successive days using the filtration method. Two stool specimens were processed using the Kato-Katz method and a third specimen was processed using the sedimentation method. Plasmodium falciparum was diagnosed from thick blood films. The prevalence of Schistosoma haematobium in the rural and farming areas was 66.8% and 52.3%, respectively, and for S. mansoni the prevalence was 12.4% and 22.7%, respectively. Plasmodium falciparum, hookworms, Ascaris lumbricoides and Trichuris trichiura occurred only in the farming area, with a prevalence of 27.9%, 23.7%, 2.1%, 2.3%, respectively. Co-infection and triple infection with schistosomes, P. falciparum and soil-transmitted helminths occurred in the commercial farming area only. Hookworm and S. mansoni infections were associated with P. falciparum malaria (P<0.001, OR=2.48, 95% CI 1.56-3.93 and P=0.005, OR=1.85, 95% CI 1.20-2.87, respectively). Overlap of helminths with malaria is a concern among primary schoolchildren and incorporating helminth control in programmes aiming to control malaria will improve funding and increase the efficiency of control for neglected tropical diseases in identified co-endemic settings.

Local therapy of cancer with free IL-2

Abstract: This is a position paper about the therapeutic effects of locally applied free IL-2 in the treatment of cancer. Local therapy: IL-2 therapy of cancer was originally introduced as a systemic therapy. This therapy led to about 20% objective responses. Systemic therapy however was very toxic due to the vascular leakage syndrome. Nevertheless, this treatment was a break-through in cancer immunotherapy and stimulated some interesting questions: Supposing that the mechanism of IL-2 treatment is both proliferation and tumoricidal activity of the tumor infiltrating cells, then locally applied IL-2 should result in a much higher local IL-2 concentration than systemic IL-2 application. Consequently a greater beneficial effect could be expected after local IL-2 application (peritumoral = juxtatumoral, intratumoral, intra-arterial, intracavitary, or intratracheal = inhalation). Free IL-2: Many groups have tried to prepare a more effective IL-2 formulation than free IL-2. Examples are slow release systems, insertion of the IL-2 gene into a tumor cell causing prolonged IL-2 release. However, logistically free IL-2 is much easier to apply; hence we concentrated in this review and in most of our experiments on the use of free IL-2. Local therapy with free IL-2 may be effective against transplanted tumors in experimental animals, and against various spontaneous carcinomas, sarcomas, and melanoma in veterinary and human cancer patients. It may induce rejection of very large, metastasized tumor loads, for instance advanced clinical tumors. The effects of even a single IL-2 application may be impressive. Not each tumor or tumor type is sensitive to local IL-2 application. For instance transplanted EL4 lymphoma or TLX9 lymphoma were not sensitive in our hands. Also the extent of sensitivity differs: In Bovine Ocular Squamous Cell Carcinoma (BOSCC) often a complete regression is obtained, whereas with the Bovine Vulval Papilloma and Carcinoma Complex (BVPCC) mainly stable disease is attained. Analysis of the results of local IL-2 therapy in 288 cases of cancer in human patients shows that there were 27% Complete Regressions (CR), 23% Partial Regressions (PR), 18% Stable Disease (SD), and 32% Progressive Disease (PD). In all tumors analyzed, local IL-2 therapy was more effective than systemic IL-2 treatment. Intratumoral IL-2 applications are more effective than peritumoral application or application at a distant site. Tumor regression induced by intratumoral IL-2 application may be a fast process (requiring about a week) in the case of a highly vascular tumor since IL-2 induces vascular leakage/edema and consequently massive tumor necrosis. The latter then stimulates an immune response. In less vascular tumors or less vascular tumor sites, regression may require 9–20 months; this regression is mainly caused by a cytotoxic leukocyte reaction. Hence the disadvantageous vascular leakage syndrome complicating systemic treatment is however advantageous in local treatment, since local edema may initiate tumor necrosis. Thus the therapeutic effect of local IL-2 treatment is not primarily based on tumor immunity, but tumor immunity seems to be useful as a secondary component of the IL-2 induced local processes. If local IL-2 is combined with surgery, radiotherapy or local chemotherapy the therapeutic effect is usually greater than with either therapy alone. Hence local free IL-2 application can be recommended as an addition to standard treatment protocols. Local treatment with free IL-2 is straightforward and can readily be applied even during surgical interventions. Local IL-2 treatment is usually without serious side effects and besides minor complaints it is generally well supported. Only small quantities of IL-2 are required. Hence the therapy is relatively cheap. A single IL-2 application of 4.5 million U IL-2 costs about 70 Euros. Thus combined local treatment may offer an alternative in those circumstances when more expensive forms of treatment are not available, for instance in resource poor countries.

Efficacy and side effects of praziquantel treatment against Schistosoma haematobium infection among primary school children in Zimbabwe

Abstract: We examined the efficacy of praziquantel against Schistosoma haematobium among primary school children during a school-based deworming programme in the Burma Valley commercial farming area and the Nyamaropa rural areas in Zimbabwe, where the disease is highly endemic. Among 767 individuals infected with S. haematobium, 675 (88.0%) received treatment. Two single oral doses of 40mg/kg praziquantel were given 6 weeks apart. Of the 675 participants, heavy infection intensity was more common in males than females (chi(2)=6.61, P=0.010). Six weeks later, 624 participants (92.4%) were successfully followed up. The overall cure rate was 88.5% and the egg reduction rate was 98.2%. The highest cure rate was among those individuals with light infection. Seventy-two individuals remained infected at 6 weeks post treatment, among which 3 and 69 individuals had heavy and light infection, respectively. Forty-six of these children resolved following a second round of treatment at 6 weeks follow-up. Of the remaining children successfully followed-up, 22 resolved after a third round of treatment 6 months later. A wide range of observed mild and transient side effects were not associated with egg intensity. The parasitological cure rate was not associated with gender or age. Our study demonstrates that praziquantel is efficacious against S. haematobium in Zimbabwe, although low levels of persistent infection warrant further investigation.

Maternal versus paternal orphans and HIV/STI risk among adolescent girls in Zimbabwe.

Abstract: The AIDS epidemic has contributed to a drastic increase in the number of orphans in Zimbabwe. Orphans (whether orphaned by AIDS or other causes) have been shown to have economic and educational disadvantages as well as poor reproductive health outcomes. We recruited a convenience sample of 200 girls in a peri-urban area of Zimbabwe to examine the impact of orphan status (compared to non-orphans) on household composition, education, risk behaviour, pregnancy and prevalent HIV and HSV-2 infection. In our population, maternal orphans were more likely to be in households headed by themselves or a sibling, to be sexually active, to have had an STI, to have been pregnant and to be infected with HIV. Paternal orphans were more likely to have ever been homeless and to be out of school. Our findings suggest that maternal care and support is important for HIV prevention. This finding corroborates previous research in Zimbabwe and has implications for intervention strategies among orphan girls.

Hydrograph separation using hydrochemical tracers in the Makanya catchment, Tanzania

Abstract: Hydrochemical tracers were used to separate and quantify different runoff components in the semi-arid Makanya catchment in the South Pare Mountains of Tanzania. One flood event was investigated during the rainy season of October–December 2005 and analysed for electrical conductivity, dissolved silica and major anions and cations. The event on 9 November 2005 showed two peaks, each originating from one of two sub-catchments, upper-Vudee and Ndolwa, each with a distinct water quality signature. Hydrograph separation indicated that the two peaks in the hydrograph originated from a delay in response between the two catchments. The hydrograph separation indicated that, for this event, over 95% of the discharge could be attributed to sub-surface runoff, while the remainder was due to faster surface runoff processes. The dominance of sub-surface processes was also indicated by the lack of suspended sediments in the samples, which is a clear indication that no surface runoff took place.

Herd dynamics and contribution of indigenous pigs to the livelihoods of rural farmers in a semi-arid area of Zimbabwe

Abstract: Herd dynamics of indigenous pigs were determined in a semi-arid farming area of Chirumanzu, Zimbabwe. Thirty-two pig herds were monitored once every month for 12 months. Consequently, pig production potential (PPP) and pig production efficiency (PPE) were computed for each month. Incidences of farrowing were higher in times of pig confinement (57%) than in times when the pigs were free ranging (43%). About 23% of the farmers interviewed had access to irrigation. The mean pig herd size per household was 3.3. The average litter size per farrowing was 7.7. Pigs were free ranging for most of the year and penned during the rainy season. Herd sizes changed with month (P 0.05). It can be concluded that pig production efficiencies were low and intervention strategies to improve them need to be developed.

Age-Related and Infection Intensity-Related Shifts in Antibody Recognition of Defined Protein Antigens in a Schistosome-Exposed Population

Abstract: Background: This study compared patterns of recognition of defined Schistosoma haematobium adult worm antigens by serum antibodies from schistosome-exposed Zimbabweans aged 5–18 years. Methods: The population was stratified by age and infection intensity into 9 groups within which serum specimens were pooled and used to screen for protein recognition by 2-dimensional Western blotting. Recognized proteins were identified by electrospray ionizing tandem mass spectrometry. Results: A total of 71 antigens were recognized by ≥1 of the serum pools. The recognition varied distinctly with host age and infection intensity, with some isoform-specific responses. The repertoire of antigens recognized increased with age, peaking in the oldest participants whose had no or mild-to-moderate infection intensity. The intensity of antigen recognition also increased with age, peaking in the oldest participants with the heaviest infection intensity. Conclusions: The recognition of specific schistosome antigens, both in terms of the diversity of antigens recognized and the intensity of antigen recognition, increased with duration of exposure to infection, supporting the hypothesis that the slow development of schistosome-acquired immunity is due to the slow accumulation of responsiveness to relevant parasite antigens.

HIV incidence in 3 years of follow-up of a Zimbabwe cohort—1998–2000 to 2001–03: contributions of proximate and underlying determinants to transmission

Abstract: In recent years HIV prevalence has begun to decline in Zimbabwe which has been associated with reductions in sexual risk behaviour. Here we analyse the determinants of HIV incidence in this period of decline and estimate the population-level impact of identified risk factors. A population-based cohort of 1672 HIV-negative adult males and 2465 HIV-negative adult females was recruited between 1998 and 2000. Each individual was then followed-up 3 years later. The influence and inter-relationship of social behavioural and demographic variables were examined using a proximate determinants framework. To explore the population-level influence of a variable methods were developed for estimating a risk factors contribution to the reproductive number (CRN). HIV incidence was 19.9 [95% confidence interval (CI) 16.3-24.2] per 1000 person years in men and 15.7 (95% CI 13.0-18.9) in women. Multiple sexual partners having an unwell partner and reporting another sexually transmitted disease were risk factors that captured the main aspects of the proximate determinants framework: individual behaviour partnership characteristics and the probability of transmission respectively. If the proximate determinants fully captured risk of HIV infection underlying factors would not influence a fully parameterized model. However a number of underlying social and demographic determinants remained important in regression models after including the proximate determinants. For both sexes having multiple sexual partners made a substantial CRN but for women no behaviour explained more than 10% of new infections. The proximate determinants did not explain the majority of new infections at the population level. This may be because we have been unable to measure some risks but identifying risk factors assumes that those acquiring infections are somehow different from others who do not acquire infections. That they are not suggests that in this generalized epidemic there is little difference in readily identifiable characteristics of the individual between those who acquire infection and those who do not. (authors)

Help-seeking behaviour for sexual-health concerns: A qualitative study of men in Zimbabwe.

Abstract: Using data collected through semi-structured interviews and focus group discussions with adult men in Zimbabwe, this paper explores the decision-making process associated with help-seeking for sexual-health concerns. Help-seeking is located in the complex and dynamic socio-cultural contexts around men's sexualities, masculinities and reproductive health. Pathways to help-seeking include identifying symptoms and the condition, seeking information and advice, and seeking and accessing treatment. Health is grounded in the cultural, spiritual and religious context of Zimbabwean men's lives. Men interpreted sexual-health concerns as due to either natural (disease, psychological stress) or supernatural (displeased ancestral and religious spirits, witchcraft) causes. These interpretations influence their choice of treatment and health service provider. Dominant gender norms of resilience and self-reliance, together with shyness and embarrassment, can delay men's treatment-seeking. The HIV epidemic has made sexual health a more prominent issue in society. However, HIV-related stigma can hinder men's help-seeking for sexual-health concerns (particularly for sexually transmitted infections). Understanding and taking account of these issues in research, health promotion and healthcare services should benefit the sexual health of both men and women.

Selection in the Making: A Worldwide Survey of Haplotypic Diversity Around a Causative Mutation in Porcine IGF2

Abstract: Domestic species allow us to study dramatic evolutionary changes at an accelerated rate due to the effectiveness of modern breeding techniques and the availability of breeds that have undergone distinct selection pressures. We present a worldwide survey of haplotype variability around a known causative mutation in porcine gene IGF2, which increases lean content. We genotyped 34 SNPs spanning 27 kb in 237 domestic pigs and 162 wild boars. Although the selective process had wiped out variability for at least 27 kb in the haplotypes carrying the mutation, there was no indication of an overall reduction in genetic variability of international vs. European local breeds; there was also no evidence of a reduction in variability caused by domestication. The haplotype structure and a plot of Tajima's D against the frequency of the causative mutation across breeds suggested a temporal pattern, where each breed corresponded to a different selective stage. This was observed comparing the haplotype neighbor-joining (NJ) trees of breeds that have undergone increasing selection pressures for leanness, e.g., European local breeds vs. Pietrain. These results anticipate that comparing current domestic breeds will decisively help to recover the genetic history of domestication and contemporary selective processes.

The Diaphragm and Lubricant Gel for Prevention of Cervical Sexually Transmitted Infections: Results of a Randomized Controlled Trial

Abstract: BACKGROUND: We evaluated the effectiveness of the Ortho All-Flex Diaphragm lubricant gel (Replens) and condoms compared to condoms alone on the incidence of chlamydial and gonococcal infections in an open-label randomized controlled trial among women at risk of HIV/STI infections. METHODS: We randomized 5045 sexually-active women at three sites in Southern Africa. Participants who tested positive for curable STIs were treated prior to enrollment as per local guidelines. Women were followed quarterly and tested for Chlamydia trachomatis (CT) or Neisseria gonorrhoeae (GC) infection by nucleic-acid amplification testing (Roche Amplicor) using first-catch urine specimens. STIs detected at follow-up visits were treated. We compared the incidence of first infection after randomization between study arms in both intent-to-treat (ITT) and per-protocol populations. FINDINGS: Baseline demographic behavioral and clinical characteristics were balanced across study arms. Nearly 80% of participants were under35 years of age. Median follow-up time was 21 months and the retention rate was over 93%. There were 471 first chlamydia infections 247 in the intervention arm and 224 in the control arm with an overall incidence of 6.2/100 woman-years (wy) (relative hazard (RH) 1.11 95% Confidence Interval (CI): 0.93-1.33; p = 0.25) and 192 first gonococcal infections 95 in the intervention arm and 97 in the control arm with an overall incidence of 2.4/100wy (RH 0.98 95%CI: 0.74-1.30; p = 0.90). Per protocol results indicated that when diaphragm adherence was defined as "always use" since the last visit there was a significant reduction in the incidence of GC infection among women randomized to the intervention arm (RH 0.61 95%CI: 0.41-0.91 P = 0.02). INTERPRETATION: There was no difference by study arm in the rate of acquisition of CT or GC. However our per-protocol results suggest that consistent use of the diaphragm may reduce acquisition of GC. TRIAL REGISTRATION: ClinicalTrials.gov NCT00121459.