Biomedical subjects

I Kleinschmidt

Publications and source records attributed to I Kleinschmidt.

At least 19 recordsLinked to original sources

PubMed2004

Spatial patterns of infant mortality in Mali: the effect of malaria endemicity.

A spatial analysis was carried out to identify factors related to geographic differences in infant mortality risk in Mali by linking data from two spatially structured databases: the Demographic and Health Surveys of 1995-1996 and the Mapping Malaria Risk in Africa database for Mali. Socioeconomic factors measured directly at the individual level and site-specific malaria prevalence predicted for the Demographic and Health Surveys' locations by a spatial model fitted to the Mapping Malaria Risk in Africa database were examined as possible risk factors. The analysis was carried out by fitting a Bayesian hierarchical geostatistical logistic model to infant mortality risk, by Markov chain Monte Carlo simulation. It confirmed that mother's education, birth order and interval, infant's sex, residence, and mother's age at infant's birth had a strong impact on infant mortality risk in Mali. The residual spatial pattern of infant mortality showed a clear relation to well-known foci of malaria transmission, especially the inland delta of the Niger River. No effect of estimated parasite prevalence could be demonstrated. Possible explanations include confounding by unmeasured covariates and sparsity of the source malaria data. Spatial statistical models of malaria prevalence are useful for indicating approximate levels of endemicity over wide areas and, hence, for guiding intervention strategies. However, at points very remote from those sampled, it is important to consider prediction error.

Adult↗

PubMed2004

Exploring 30 years of malaria case data in KwaZulu-Natal, South Africa: part I. The impact of climatic factors.

Large parts of Africa are prone to malaria epidemics. Advance epidemic warning would give health services an opportunity to prepare. Because malaria transmission is largely limited by climate, climate-based epidemic warning systems are a real possibility. To develop and test such a system, good long-term malaria and climate data are needed. In KwaZulu-Natal (KZN), South Africa, 30 years of confirmed malaria case data provide a unique opportunity to examine short- and long-term trends. We analysed seasonal case totals and seasonal changes in cases (both log-transformed) against a range of climatic indicators obtained from three weather stations in the highest malaria incidence districts, using linear regression analysis. Seasonal changes in case numbers (delta log cases, dlc) were significantly associated with several climate variables. The two most significant ones were mean maximum daily temperatures from January to October of the preceding season (n=30, r2=0.364, P=0.0004) and total rainfall during the current summer months of November-March (n=30, r2=0.282, P=0.003). These two variables, when entered into the same regression model, together explained 49.7% of the total variation in dlc. We found no evidence of association between case totals and climate. In KZN, where malaria control operations are intense, climate appears to drive the interannual variation of malaria incidence, but not its overall level. The accompanying paper provides evidence that overall levels are associated with non-climatic factors such as drug resistance and possibly HIV prevalence.

Climate↗

PubMed2004

Exploring 30 years of malaria case data in KwaZulu-Natal, South Africa: part II. The impact of non-climatic factors.

Malaria transmission is a multifactorial phenomenon. Climate is a major limiting factor in the spatial and temporal distribution of malaria, but many non-climatic factors may alter or override the effect of climate. Thirty years of monthly malaria incidence data from KwaZulu-Natal province, South Africa, reveal strong medium and long-term trends, which were not present in the climate data. This paper explores various non-climatic factors that may have contributed towards the observed trends. The development of antimalarial drug resistance, available information on human immunodeficiency virus (HIV) prevalence, cross-border people movements, agricultural activities, emergence of insecticide resistance and the case reporting system are reviewed and their potential effect on malaria transmission examined. Single-variable linear regression analysis showed significant association between seasonal case totals (log-transformed) and the measured level of drug resistance (log-transformed) (r2=0.558, n=10, P=0.013) as well as relative measures of HIV infection since 1990 (r2=0.846, n=11, P=0.001). The other factors appear to have affected the level of malaria transmission at certain periods and to some degree. The importance of surveillance and inclusion of non-climatic variables in analysis of malaria data is demonstrated.

Agriculture↗

PubMed2003

Temperature-suitability maps for schistosomiasis in South Africa.

The results of parasitological surveys have shown that both urinary and intestinal schistosomiasis occur widely among the human residents of South Africa. The national data on both diseases have now been incorporated into a geographical information system, to develop new maps based on defined temperature constraints. The disease data, obtained from a 'hard-copy' atlas of schistosomiasis, were used as a template to select temperature regimes that were (1) suitable and (2) unsuitable for the transmission of schistosomes to humans in South Africa. The regimes were derived from the published results of investigations in which the biology of larval schistosomes (i.e. schistosome transmission) was related to temperature in South Africa. Those regimes that were based on the estimated temperature minima for transmission corresponded more closely to the disease-distribution data than those based on the corresponding maxima. An estimate of the number of children living in the climate-suitable areas was made but, within the context of the spatial methodology used and the limitations of the available disease data, it was not possible to predict the prevalences of schistosomiasis.

Adolescent↗

PubMed2003

An epidemiological perspective of substance use among high school pupils in rural KwaZulu-Natal.

OBJECTIVES: To investigate prevalence and the factors influencing substance use among rural high school pupils in KwaZulu-Natal in order to develop and implement intervention programmes. DESIGN: Cross-sectional study. SETTING: Twenty-eight high schools in southern KwaZulu-Natal. SUBJECTS: One thousand three hundred and eighteen grade 10 pupils. OUTCOME MEASURES: An anonymous self-reporting questionnaire was used to investigate the use of alcohol, tobacco (cigarettes), cannabis and solvents. RESULTS: Of the male scholars, 52.9% (95% confidence interval (CI): 45.4-60.3) reported ever using alcohol, 16.9% (CI: 11.5-24.0) reported using cannabis, and 13.1% (CI: 7.2-22.5) had smoked more than one cigarette daily. Among male pupils 45.5% (CI: 38.6-52.6) had inhaled benzine and 34.6% (CI: 28.0-41.8), thinners; 7.4% (CI: 3.4-15.2) had used cocaine and 4.1% (CI: 1.0-10.6), crack. Female pupils reported significantly less use of alcohol (25.5%, CI: 17.6-35.3), cannabis (2.3%, CI: 1.3-4.1), cigarettes (more than one daily) (2.0%, CI: 1.0-4.1), and inhalation of benzine (18.8%, CI: 13.8-25.2) and thinners (10.8%, CI: 7.2-16). Logistical regression indicated that the odds of smoking cigarettes increased significantly (p < 0.0005) with use of the other substances. CONCLUSION: The results of this study confirm the prevalence of multi-substance use among pupils at the majority of rural high schools in this district and the need for targeted interventions to reduce/prevent this.

Adolescent↗

PubMed2002

Prevalence, incidence, and mother-to-child transmission of HIV-1 in rural South Africa.

Simple, robust approaches are needed to monitor prevalence, incidence, and mother-to-child transmission of HIV-1 in rural Africa. We have designed a method that uses antibody and viral RNA testing of dried blood spots obtained from mother-infant pairs attending routine immunisation clinics. In our study, prevalence and incidence of HIV-1 was highest in young women in their late teens and early twenties. In children born to infected mothers, prevalence increased from 14% in infants younger than 6 weeks of age to 24% at 3-6 months. The blood-spot approach is an effective method for surveillance of HIV-1 in women and children, and for early identification of incidence of this infection in women of child-bearing age.

Adolescent↗

PubMed2002

The use of spatial analysis in mapping the distribution of bancroftian filariasis in four West African countries.

The geographical distribution of human infection with Wuchereria bancrofti was investigated in four West African countries (Benin, Burkina Faso, Ghana and Togo), using a commercial immunochromatographic test for filarial antigen. Efforts were made to cover each health-system implementation unit and to ensure no sampling point was >50 km from another, but otherwise the 401 study communities were selected at random. The aim was to enable spatial analysis of the data, to provide a prediction of the overall spatial relationships of the infection. The results, which were subjected to an independent random validation in Burkina Faso and Ghana, revealed that prevalence in the adult population of some communities exceeded 70% and that, over large areas of Burkina Faso, community prevalences were between 30% and 50%. Most of Togo, southern Benin and much of southern Ghana appeared completely free of the infection. Although there were foci on the Ghanaian coast with prevalences of 10%-30%, such high prevalences did not extend into coastal Togo or costal Benin. The prevalence map produced should be useful in prioritizing areas for filariasis control, identifying potential overlap with ivermectin-distribution activities undertaken by onchocerciasis-control programmes, and enabling inter-country and sub-regional planning to be initiated. The results indicate that bancroftian filariasis is more widely distributed in arid areas of Burkina Faso than hitherto recognized and that the prevalences of infection have remained fairly stable for at least 30 years. The campaign to eliminate lymphatic filariasis as a public-health problem in Africa will require significantly more resources (human, financial, and logistic) than previously anticipated.

Adolescent↗

PubMed2001

Use of generalized linear mixed models in the spatial analysis of small-area malaria incidence rates in Kwazulu Natal, South Africa.

Spatial statistical analysis of 1994-1995 small-area malaria incidence rates in the population of the northernmost districts of KwaZulu Natal, South Africa, was undertaken to identify factors that might explain very strong heterogeneity in the rates. In this paper, the authors describe a method of adjusting the regression analysis results for strong spatial correlation in the rates by using generalized linear mixed models and variograms. The results of the spatially adjusted, multiple regression analysis showed that malaria incidence was significantly positively associated with higher winter rainfall and a higher average maximum temperature and was significantly negatively associated with increasing distance from water bodies. The statistical model was used to produce a map of predicted malaria incidence in the area, taking into account local variation from the model prediction if this variation was supported by the data. The predictor variables showed that even small differences in climate can have very marked effects on the intensity of malaria transmission, even in areas subject to malaria control for many years. The results of this study have important implications for malaria control programs in the area.

Climate↗

PubMed2001

Structural integrity of the female condom after multiple uses, washing, drying, and re-lubrication.

Establishing the safety of re-using the female condom could significantly increase women's access to barrier methods especially in poorer countries. In this study, the structural integrity of female condoms was tested (n = 295) after multiple acts of vaginal intercourse. Fifty women were recruited to the study. Each woman re-used one condom up to eight times and washed, dried, and re-lubricated between each use. Structural integrity was measured using standard quality control testing; water-leakage, air-burst, and seam tensile strength. All results were compared to the United States Food and Drug Administration (US FDA) standards for an unused female condom. The results of the structural integrity tests for all cycles were above the FDA minimum standards for seam strength and burst tests. There was no deterioration detected in condoms used 8 times when compared to new female condoms in these tests. Five holes were detected by the water leakage test across all cycles, of which three were detected by the subjects themselves and reported to the investigators, therefore, giving a breakage rate of 1.7%. The holes were not associated with increased number of uses. This study provides further evidence that suggests the structural integrity of the female condom after multiple use is still within FDA minimum standards, although random holes resulting from handling occur infrequently with the re-use procedure.

Coitus↗

PubMed2001

An empirical malaria distribution map for West Africa.

The objective of this study was to produce a malaria distribution map that would constitute a useful tool for development and health planners in West Africa. The recently created continental database of malaria survey results (MARA/ARMA 1998) provides the opportunity for producing empirical models and maps of malaria distribution at a regional and eventually at a continental level. This paper reports on the mapping of malaria distribution for sub-Saharan West Africa based on these data. The strategy was to undertake a spatial statistical analysis of malaria parasite prevalence in relation to those potential bio-physical environmental factors involved in the distribution of malaria transmission intensity which are readily available at any map location. The resulting model was then used to predict parasite prevalence for the whole of West Africa. We also produced estimates of the proportion of population of each country in the region exposed to various categories of risk to show the impact that malaria is having on individual countries. The data represent a very large sample of children in West Africa. It constitutes a first attempt to produce a malaria risk map of the West African region, based entirely on malariometric data. We anticipate that it will provide useful additional guidance to control programme managers, and that it can be refined once sufficient additional data become available.

Adolescent↗

PubMed2001

Patterns in age-specific malaria incidence in a population exposed to low levels of malaria transmission intensity.

The population of the northern part of the province of KwaZulu Natal in South Africa has experienced low levels of malaria transmission intensity for many years. We investigated the widely held assumption that individuals in this population do not develop clinical tolerance to infection with Plasmodium falciparum. We calculated malaria incidence rates by 5-year age groups from a comprehensive small area malaria reporting system and from national census data for the period from mid-1990 to mid-1999. Incidence rates were plotted against age groups for each of the nine malaria seasons, and by quintile of crude incidence rate. These show that age-specific incidence varied considerably in areas of high incidence and in years of high incidence. In these areas malaria incidence rose with age until the late teens, and either remained constant or decreased in young adults. This finding appears to be consistent with results from settings of much higher transmission intensities which show that clinical tolerance to infection with P. falciparum in adults may be acquired as a result of a small number of infective bites in early childhood and implies that even in this relatively low transmission area, there is an asymptomatic reservoir of infection in older people. The results also show that in high incidence subregions the lowest incidences are reported for children under 5 years of age, which may be the result of greater protection offered to this age group by malaria vector control through indoor house spraying.

Adolescent↗

PubMed2001

Cyclin E immunoexpression in breast ductal carcinoma: pathologic correlations and prognostic implications.

Abnormalities of the cell cycle are present in all neoplasms. Cyclin E, which regulates the G1/S phase transition of the cell cycle, plays an important role in many different cancers. To further investigate the role of cyclin E in invasive breast ductal carcinomas in South African women, representative sections from 157 mastectomy and axillary clearance specimens were stained with the cyclin E antibody. The results were compared with known clinicopathologic prognostic factors, namely lymph node metastases, size, estrogen receptor status, and histologic grade. Positive (nuclear) cyclin E immunostaining strongly correlates with negative estrogen receptor status and high grade. These correlations may account for the observation that although cyclin E staining is associated with poor prognosis in univariate analysis, no prognostic significance remains after multivariate analysis.

Aged↗

PubMed2001

A randomised controlled trial of antibiotic prophylaxis in elective caesarean delivery.

OBJECTIVE: To determine whether prophylactic antibiotic administration using cefoxitin at the time of elective caesarean section significantly reduces infectious morbidity. SETTING: A tertiary teaching hospital in a large urban city in South Africa. PARTICIPANTS: Women undergoing elective caesarean section. DESIGN: A prospective, double-blind randomised placebo-controlled trial. METHODS: Four hundred and eighty women undergoing elective caesarean section had cefoxitin or placebo administration after umbilical cord clamping. Postpartum complications including febrile morbidity, wound infection, endometritis, urinary tract infection, pneumonia and transient postpartum fever were recorded, as were the duration of hospital stay and the need for therapeutic antibiotics. RESULTS: Wound infection was the most common complication occurring in 13.3% and 12.5% of women in the placebo and cefoxitin groups, respectively. Prophylactic antibiotics did not decrease febrile morbidity, wound infection, endometritis, urinary tract infection and pneumonia. Women who received cefoxitin stayed on average a day less in hospital than those who received placebo (6.9 vs 7.8 days, risk difference 0.94 CI 1.57 - 0.31 days). Eleven women (4.6%) in the placebo group and eight (3.4%) in the cefoxitin group had microbiological evidence of wound infection. Staphylococcus aureus was the most common pathogen (43%) isolated. Similar proportions in both groups (6.3% placebo and 5.1% cefoxitin) required a course of therapeutic antibiotics. CONCLUSION: Antibiotic prophylaxis with cefoxitin in elective caesarean section did not reduce post-operative infectious morbidity in this double-blind randomised placebo controlled trial.

Adult↗

PubMed2001

Prevalence of HIV and HIV-related diseases in the adult medical wards of a tertiary hospital in Durban, South Africa.

Our objective was to determine the prevalence of HIV and the distribution of HIV-related diseases among adult, medical inpatients. Consecutive admissions were recruited and a single ELISA assay was used to determine HIV infection. Demographic and clinical details were extracted from clinical records. Of 507 patients, 54% were infected with HIV of which 84% had AIDS. HIV-infected patients were significantly younger (34.9 years) than uninfected patients (47.1 years) and had significantly higher risks for oral/oesophageal candidiasis (risk ratio [RR] 18.6), generalized lymphadenopathy (RR 7.1), unexplained fever (RR 7.0), chronic diarrhoea (RR 6.2) and pulmonary tuberculosis (RR 3.1). Pulmonary tuberculosis was present in 56% of HIV cases. Mortality was 22% for HIV cases and 9% (P=0.016) for others. The mean length of hospital stay was the same for HIV-infected and uninfected patients. AIDS is the most common reason for admission to adult medical wards and will increasingly limit the number of beds available for non-AIDS patients.

AIDS-Related Opportunistic Infections↗

PubMed2001

Malaria control--two years' use of insecticide-treated bednets compared with insecticide house spraying in KwaZulu-Natal.

OBJECTIVES: The objective of this study was to produce data indicating whether insecticide-treated bednets should replace insecticide house spraying as a malaria control method in South Africa. We report 2 years of preliminary data on malaria incidence comparing areas receiving insecticide-treated bednets and those subjected to house spraying in northern KwaZulu-Natal. DESIGN, SETTING AND SUBJECTS: In order to measure significant reductions in malaria incidence between the two interventions, a geographical information system (GIS) was used to identify and create seven pairs of geographical blocks (areas) in the malaria high-risk areas of Ndumu and Makanis in Ingwavuma magisterial district, KwaZulu-Natal. Individual blocks were then randomly allocated to either insecticide-treated bednets or house spraying with deltamethrin. Malaria cases were either routinely recorded by surveillance agents at home or were reported to the nearest health facility. RESULTS AND CONCLUSIONS: The results show that 2 years' use of insecticide-treated bednets by communities in Ndumu and Makanis, KwaZulu-Natal, significantly reduced the malaria incidence both in 1997 (rate ratio (RR) = 0.879, 95% confidence interval (CI) 0.80-0.95, P = 0.04) and in 1998 (RR = 0.667, CI 0.61-0.72, P = 0.0001). Using a t-test, these significant reductions were further confirmed by an assessment of the rate of change between 1996 and 1998, showing a 16% reduction in malaria incidence in blocks using treated bednets and an increase of 45% in sprayed areas (t = 2.534, P = 0.026 (12 df)). In order to decide whether bednets should replace house spraying in South Africa, we need more data on the efficacy of treated bednets, their long-term acceptability and the cost of the two interventions.

Aerosols↗

PubMed2000

In vitro assessment of the structural integrity of the female condom after multiple wash, dry, and re-lubrication cycles.

Since the introduction of the female condom in the early 90s, there have been numerous reports of reuse of the device. In response to these reports, studies were undertaken to evaluate the safety of female condom reuse. If reuse were shown to be safe, then programmatic costs of introduction of the female condom would be reduced allowing it to be more widely available. This article outlines the results of in vitro structural integrity testing of the female condom after multiple wash, dry, and re-lubrication cycles. Devices were tested up to 10 washes using water leakage, burst, and tensile seam testing. All results were compared to the United States Food and Drug Administration (US FDA) standards for an unused female condom. The results of the structural integrity tests for all 6 washing procedures examined in this study were above the FDA minimum standards for seam strength and burst tests. For the water leakage test, 3 of 6 washing procedures tested passed the required FDA minimum standards (no holes detected). From the results of the study, it seems that washing, drying, and re-lubricating the female condom up to 10 times leads to some deterioration in the structural integrity of the device for specified washing procedures. Further studies are currently being conducted to establish the safety of female condom reuse with respect to microbial retention, structural integrity after in vivo use, and viral permeability.

Single-Use Internal Condom↗

PubMed2000

A spatial statistical approach to malaria mapping.

BACKGROUND: Good maps of malaria risk have long been recognized as an important tool for malaria control. The production of such maps relies on modelling to predict the risk for most of the map, with actual observations of malaria prevalence usually only known at a limited number of specific locations. Estimation is complicated by the fact that there is often local variation of risk that cannot be accounted for by the known covariates and because data points of measured malaria prevalence are not evenly or randomly spread across the area to be mapped. METHOD: We describe, by way of an example, a simple two-stage procedure for producing maps of predicted risk: we use logistic regression modelling to determine approximate risk on a larger scale and we employ geo-statistical ('kriging') approaches to improve prediction at a local level. Malaria prevalence in children under 10 was modelled using climatic, population and topographic variables as potential predictors. After the regression analysis, spatial dependence of the model residuals was investigated. Kriging on the residuals was used to model local variation in malaria risk over and above that which is predicted by the regression model. RESULTS: The method is illustrated by a map showing the improvement of risk prediction brought about by the second stage. The advantages and shortcomings of this approach are discussed in the context of the need for further development of methodology and software.

Child↗

PubMed2000

Mitral stenosis in pregnancy: a four-year experience at King Edward VIII Hospital, Durban, South Africa.

OBJECTIVE: To evaluate prospectively mitral stenosis in pregnancy with emphasis on women with persistent symptoms. SETTING: King Edward VIII Hospital, a tertiary referral obstetric unit. PARTICIPANTS: One hundred and twenty-eight consecutive women with mitral stenosis. DEMOGRAPHICS: The mean age was 27 years and 38 women (30%) were primigravidae. Seventy-eight (61%) women had their first cardiac evaluation in the third trimester. Fifty-four women (42%) of these women had mitral stenosis diagnosed for the first time in the index pregnancy. Twenty-nine (23%) had a previous mitral valvulotomy. Nineteen women (15%) developed hypertension during pregnancy, 10 of whom had pre-eclampsia. Sixty-three women (49%) had a mitral valve area of < or = 1.2 cm2 with 11 having critical mitral stenosis (mitral valve area < or = 0.8 cm2). Atrial fibrillation was present in 12 women. Most women (87%) required medical therapy to control the heart rate. OUTCOME IN PERSISTENT SYMPTOMATIC WOMEN: Intervention was considered in 37 women (29%) who remained symptomatic, 11 (9%) of whom had a calcified mitral valve. The remaining 26 women were scheduled for balloon mitral valvulotomy during pregnancy, 20 of whom had balloon mitral valvulotomy with good effect (16 antepartum; 4 postpartum). In seven women, scheduled balloon mitral valvulotomy was not performed because of advanced preterm labour (n = 5), fetal distress (n = 1) and preterm labour with fetal distress (n = 1). These seven, together with the 11 with calcific mitral stenosis, were managed conservatively with good outcome. MATERNAL COMPLICATIONS: Fifty-one percent had maternal complications, the majority occurring at their initial admission to hospital. Pulmonary oedema was the most frequent. Multiple logistic regression analysis showed that the severity of stenosis assessed by measurement of the mitral valve area by echo-Doppler was the most powerful predictor of maternal pulmonary oedema. The other factors were late antenatal presentation, presence of symptoms prior to the index pregnancy and diagnosis of cardiac disease for the first time in the index pregnancy. CONCLUSION: Despite serious disease, women with persistent symptoms treated either by balloon mitral valvulotomy where feasible, or conservatively with close noninvasive monitoring, had a satisfactory fetal and maternal outcome.

Adolescent↗