Search

Objectives: The contribution of African authors to the biomedical literature is small. We evaluated the African and non‐African scientific production published in the international literature on the COVID‐19 in Africa during the first year of the epidemic (2020). Methods: Papers on COVID‐19 in Africa were extracted from the Medline (PubMed) database for bibliometric analysis including the proportions of three leading and last authors by study type, study country, authors' and laboratories/institutions' countries of affiliation and journal ranking. Results: A total of 160 articles fulfilling the inclusion criteria were analysed. The majority (91.3%) was produced by half (53.7%) of African countries, with important regional disparities, and generally without sources of funding mentioned. The majority (>85.0) of authors in lead positions (first, second, third and last authors) were Africans. Only a small number (8.7%) of studies on COVID‐19 in Africa were carried out by laboratories not on the African continent (mainly Europe, USA and China) and generally received funding. The last and first authors were more frequently of non‐African origin in journals with an Impact Factor ranking ≥1, and more frequently of African origin in journals with a lower ranking (< 1). The first and last non‐African authors tended to report their studies in high ranking ≥1 journals. Conclusions: Our study demonstrates that the emergence of promising African research capable of publishing in indexed but low‐impact factor medical journals and reveals the persistence of a North‐South asymmetry in international cooperation in biomedical research with Africa. [ABSTRACT FROM AUTHOR]

Objective: To review the findings of studies of pharyngeal carriage of Neisseria meningitidis and related species conducted in the African meningitis belt since a previous review published in 2007.Methods: PubMed and Web of Science were searched in July 2018 using the terms 'meningococcal OR Neisseria meningitidis OR lactamica AND carriage AND Africa', with the search limited to papers published on or after 1st January 2007. We conducted a narrative review of these publications.Results: One hundred and thirteen papers were identified using the search terms described above, 20 of which reported new data from surveys conducted in an African meningitis belt country. These papers described 40 surveys conducted before the introduction of the group A meningococcal conjugate vaccine (MenAfriVacR ) during which 66 707 pharyngeal swabs were obtained. Carriage prevalence of N. meningitidis varied substantially by time and place, ranging from <1% to 24%. The mean pharyngeal carriage prevalence of N. meningitidis across all surveys was 4.5% [95% CI: 3.4%, 6.8%] and that of capsulated N. meningitidis was 2.8% [95% CI: 1.9%; 5.2%]. A study of households provided strong evidence for meningococcal transmission within and outside households. The introduction of MenAfriVac® led to marked reductions in carriage of the serogroup A meningococcus in Burkina Faso and Chad.Conclusions: Recent studies employing standardised methods confirm the findings of older studies that carriage of N. meningitidis in the African meningitis belt is highly variable over time and place, but generally occurs with a lower prevalence and shorter duration than reported from industrialised countries. [ABSTRACT FROM AUTHOR]

Efforts to control malaria have been boosted in the past few years with increased international funding and greater political commitment. Consequently, the reported malaria burden is being reduced in a number of countries throughout the world, including in some countries in tropical Africa where the burden of malaria is greatest. These achievements have raised new hopes of eradicating malaria. This paper summarizes the outcomes of a World Health Organization’s expert meeting on the feasibility of such a goal. Given the hindsight and experience of the Global Malaria Eradication Programme of the 1950s and 1960s, and current knowledge of the effectiveness of antimalarial tools and interventions, it would be feasible to effectively control malaria in all parts of the world and greatly reduce the enormous morbidity and mortality of malaria. It would also be entirely feasible to eliminate malaria from countries and regions where the intensity of transmission is low to moderate, and where health systems are strong. Elimination of malaria requires a re-orientation of control activity, moving away from a population-based coverage of interventions, to one based on a programme of effective surveillance and response. Sustained efforts will be required to prevent the resurgence of malaria from where it is eliminated. Eliminating malaria from countries where the intensity of transmission is high and stable such as in tropical Africa will require more potent tools and stronger health systems than are available today. When such countries have effectively reduced the burden of malaria, the achievements will need to be consolidated before a programme re-orientation towards malaria elimination is contemplated. Malaria control and elimination are under the constant threat of the parasite and vector mosquito developing resistance to medicines and insecticides, which are the cornerstones of current antimalarial interventions. The prospects of malaria eradication, therefore, rest heavily on the outcomes of research and development for new and improved tools. Malaria control and elimination are complementary objectives in the global fight against malaria. [ABSTRACT FROM AUTHOR]

Objectives: Malaria risk maps have re-emerged as an important tool for appropriately targeting the limited resources available for malaria control. In Sub-Saharan Africa empirically derived maps using standardized criteria are few and this paper considers the development of a model of malaria risk for East Africa.Methods: Statistical techniques were applied to high spatial resolution remotely sensed, human settlement and land-use data to predict the intensity of malaria transmission as defined according to the childhood parasite ratio (PR) in East Africa. Discriminant analysis was used to train environmental and human settlement predictor variables to distinguish between four classes of PR risk shown to relate to disease outcomes in the region.Results: Independent empirical estimates of the PR were identified from Kenya, Tanzania and Uganda (n = 330). Surrogate markers of climate recorded on-board earth orbiting satellites, population settlement, elevation and water bodies all contributed significantly to the predictive models of malaria transmission intensity in the sub-region. The accuracy of the model was increased by stratifying East Africa into two ecological zones. In addition, the inclusion of urbanization as a predictor of malaria prevalence, whilst reducing formal accuracy statistics, nevertheless improved the consistency of the predictive map with expert opinion malaria maps. The overall accuracy achieved with ecological zone and urban stratification was 62% with surrogates of precipitation and temperature being among the most discriminating predictors of the PR.Conclusions: It is possible to achieve a high degree of predictive accuracy for Plasmodium falciparum parasite prevalence in East Africa using high-spatial resolution environmental data. However, discrepancies were evident from mapped outputs from the models which were largely due to poor coverage of malaria training data and the comparable spatial resolution of predictor data. These deficiencies will only be addressed by more random, intensive small areas studies of empirical estimates of PR. [ABSTRACT FROM AUTHOR]

Widespread coverage of vulnerable populations with insecticide-treated nets (ITNs) constitutes an important component of the Roll Back Malaria (RBM) strategy to control malaria. The Abuja Targets call for 60% coverage of children under 5 years of age and pregnant women by 2005; but current coverage in Africa is unacceptably low. The RBM‘Strategic Framework for Coordinated National Action in Scaling-up Insecticide-Treated Netting Programmes in Africa’ promotes coordinated national action and advocates sustained public provision of targeted subsidies to maximise public health benefits, alongside support and stimulation of the private sector. Several countries have already planned or initiated targeted subsidy schemes either on a pilot scale or on a national scale, and have valuable experience which can inform future interventions. The WHO RBM‘Workshop on mapping models for delivering ITNs through targeted subsidies’ held in Zambia in 2003 provided an opportunity to share and document these country experiences. This paper brings together experiences presented at the workshop with other information on experiences of targeting subsidies on ITNs, net treatment kits and retreatment services (ITN products) in order to describe alternative approaches, highlight their similarities and differences, outline lessons learnt, and identify gaps in knowledge. We find that while there is a growing body of knowledge on different approaches to targeting ITN subsidies, there are significant gaps in knowledge in crucial areas. Key questions regarding how best to target, how much it will cost and what outcomes (levels of coverage) to expect remain unanswered. High quality, well-funded monitoring and evaluation of alternative approaches to targeting ITN subsidies is vital to develop a knowledge base so that countries can design and implement effective strategies to target ITN subsidies. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

East Coast fever (ECF) is the most important tick-borne disease in eastern, central and southern Africa and caused an estimated loss of US $186 million in 1989 in the 11 countries where it occurs. It was brought to southern Africa with cattle from Tanzania in 1901 and, over the next 3 years, devastated the cattle that had survived the rinderpest pandemic of the 1890s. Chemical control of ticks using arsenical compounds was introduced in the early 1900s and became the main control measure for both ticks and the diseases they transmit. This method of control has become less reliable over the last 30 years for many reasons, including reduced government spending on livestock and extension, the cost of acaricides, acaricide resistance, poor management of dips and spray races, and poor application of cattle movement control and quarantine. Significant advances in immunization and treatment have been made in the last 30 years, and more robust integrated strategies combining immunization, reduced frequency of chemical control and treatment are being adopted or considered. Throughout its history, ECF has been a source of great anxiety and cost to farmers, and of intense interest to research workers. Many dogmas and misconceptions have become established, some of which still flourish while others took years to demolish. This paper briefly reviews these as well as the history of the disease and explores recent epidemiological findings and their relevance to applying effective control. [ABSTRACT FROM AUTHOR]

This paper presents the results of an investigation into the utility of remote sensing (RS) using meteorological satellites sensors and spatial interpolation (SI) of data from meteorological stations, for the prediction of spatial variation in monthly climate across continental Africa in 1990. Information from the Advanced Very High Resolution Radiometer (AVHRR) of the National Oceanic and Atmospheric Administration's (NOAA) polar-orbiting meteorological satellites was used to estimate land surface temperature (LST) and atmospheric moisture. Cold cloud duration (CCD) data derived from the High Resolution Radiometer (HRR) on-board the European Meteorological Satellite programme's (EUMETSAT) Meteosat satellite series were also used as a RS proxy measurement of rainfall. Temperature, atmospheric moisture and rainfall surfaces were independently derived from SI of measurements from the World Meteorological Organization (WMO) member stations of Africa. These meteorological station data were then used to test the accuracy of each methodology, so that the appropriateness of the two techniques for epidemiological research could be compared. SI was a more accurate predictor of temperature, whereas RS provided a better surrogate for rainfall; both were equally accurate at predicting atmospheric moisture. The implications of these results for mapping short and long-term climate change and hence their potential for the study and control of disease vectors are considered. Taking into account logistic and analytical problems, there were no clear conclusions regarding the optimality of either technique, but there was considerable potential for synergy. [ABSTRACT FROM AUTHOR]

Summary. background Verbal autopsy (VA) has been widely used to ascertain causes of child deaths, but little is known about the usefulness of VA for adult deaths. This paper describes the process used to develop a VA tool for adult deaths and the results of a multicentre validation of this tool. methods A mortality classification was developed by including causes of death that might be arrived at by VAs and causes that are responsive to public health interventions. An algorithm was designed for each cause in the classification, based on classifying symptoms into essential, supportive and differential. A structured questionnaire designed to elicit information on these symptoms was developed in English translated into the local languages. The tool was validated on deaths occurring at hospitals in Tanzania (315 deaths), Ethiopia (249) and Ghana (232). Hospital records of all adult deaths occurring at the study hospitals from June 1993 to April 1995 were collected prospectively. Non-medical interviewers with at least 12 years of formal education conducted VA interviews. Causes of death were diagnosed by a panel of physicians and by a computerized algorithm. The validity of the VA was assessed by comparing the VA diagnoses with hospital diagnoses. results Specificity of VAs by physicians fell below 95% only for acute febrile illness (AFI) and TB/AIDS. Sensitivity and positive predictive value (PPV), however, varied widely both across the sites and between causes. Sensitivity was > 75% for tetanus, rabies, direct maternal causes, injuries and TB/AIDS and ranged between 60% and 74% for diarrhoea, acute abdominal conditions and AFI. The PPV was > 75% for tetanus, rabies, hepatitis and injuries and ranged between 60 and 74% for meningitis, AFI, TB/AIDS and direct maternal causes. When the communicable diseases were combined in a single group, the sensitivity was 82%, specificity 78% and PPV 85%. For the group of noncommunicable diseases the corresponding sensitivit... [ABSTRACT FROM AUTHOR]

Very little research has been devoted to the design of epidemiological tools for the monitoring and evaluation of National Human African Trypanosomiasis (HAT) Control Programmes and daily management decisions are made in the absence of accurate knowledge of the situation. This paper identifies key indicators necessary to make decisions in the field and constantly adjust control activities to changing situations. Examples are derived from the Médecins Sans Frontières (MSF) HAT Control Programme in Adjumani, Uganda. Based on the principles of quality assurance, the focus is placed on process indicators. A conceptual framework derived from a system view/planning cycle perspective is also described for the construction of indicators. Finally, some specific challenging aspects of the epidemiology of HAT are presented and the limitations of the interpretation of the indicators discussed. [ABSTRACT FROM AUTHOR]