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Industrial production, health and disease in sub-Saharan Africa.

Industrial development in Africa has carried with it significant health costs. These costs are normally defined rather narrowly by those concerned about occupational or industrial health and safety and refer only to the health consequences of worker exposure to specific hazardous processes, materials or environmental conditions associated with the workplace. A more comprehensive measurement of industrial health costs, however, must also include an assessment of the impact which industrial development and the creation of an industrial workforce has on ecological relationships, environmental conditions and patterns of sickness and health in the areas surrounding industrial centers. Traditional definitions of occupational health also tend to focus attention on the immediate causal linkages which exist between the development of particular industrial processes and specific health hazards. Yet any attempt to fully understand the causes of industrial health problems in Africa must look beyond these immediate causal linkages and examine the wider political and economic forces which determine the shape of industrial development and the extent to which the health costs of this development are borne by industrial workers and their families, as well as by people who may not be directly or even indirectly connected to industrial development, but may, nonetheless, be exposed to its health risks. The paper surveys the direct and indirect health costs of mining, large scale agriculture, and manufacturing in Africa and examines the economic and political interests which have determined the distribution of these costs.

Africa, Central↗

Isotypic distribution of HIV-1-specific antibodies in individuals from central Africa.

Individuals infected with human immunodeficiency virus type 1 (HIV-1) develop a humoral immune response to the virus's major structural gene products env, gag, and pol. The distribution of antibodies to env, gag, and pol proteins in Central African populations is of interest as they have a high level of immune system activation compared to non-African populations. Using the Western blot technique, we analyzed the isotypic distribution of anti-HIV antibodies in 45 HIV-1-infected individuals from Central Africa that were either symptomatic or asymptomatic. We observed two basic differences between the isotypic profile of individuals from Central Africa and non-African populations. Central African individuals had a strong polyisotypic response to gag and pol, which has only been observed for gag in American and European populations. In addition, individuals from Central Africa had a high frequency of IgG4 to gag and pol, 75 and 51%, respectively, as compared to 29 and 6% in a non-African population. The elevated IgG4 response may result from the high basal level of immune stimulation seen in Africans due to multiple and frequent exposures to viral, bacterial, and parasitic antigens.

Africa, Central↗

World Health Organization clinical case definition for AIDS in Africa: an analysis of evaluations.

In 1985 at a World Health Organization (WHO) workshop on AIDS in Bangui, Central African Republic, a clinical case definition of Acquired Immune Deficiency Syndrome (AIDS) was developed for developing countries, such as sub-Saharan Africa, where sophisticated diagnostic equipment is not widely available. A particular cachectic syndrome, the "slim disease", which is highly suggestive of AIDS in Africa, constitutes the substratum for the clinical definition for AIDS. The WHO/Bangui definition in adults has a sensitivity of 60%, a specificity of 90%, and a high predictive value especially in endemic areas. The WHO/Bangui clinical case definition for paediatric AIDS is less easy to use in practice. Its low sensitivity (about 35%) is in relation to its incapacity to diagnose many of the frequently observed secondary infection for paediatric AIDS according to the CDC criteria. The WHO/Bangui clinical definition for AIDS seems to be convenient for epidemiological surveillance of the HIV epidemic in Africa. Nevertheless, the low sensitivity and the low specificity result in the failure to detect some cases of full blown AIDS.

Acquired Immunodeficiency Syndrome↗

Is permanent contraception acceptable in sub-Saharan Africa?

Some authors contend that the low use of family planning in sub-Saharan Africa is due to a low demand for fertility regulation among African men and women. The present authors' experience in Africa has been that it is not the demand for family planning services, but the way services are delivered that accounts for low numbers of acceptors in Africa. The specific case of Kenya is mentioned, where improvements in the quality of sterilization services and increases in the number of institutions that can provide minilaparotomy under local anesthesia have led to an increase in the acceptance of sterilization. The authors maintain that the demand for all family planning methods does exist, and it is up to the donor agencies and family planning service providers to try to meet that demand by providing services that are efficient to providers while oriented to the clients' needs. In the case of voluntary surgical contraception, that means providing minilaparotomy under local anesthesia.

Africa↗

Coitus, the proximate determinant of conception: inter-country variance in sub-Saharan Africa.

There is a general consensus in the literature that fertility differences between populations can be accounted for by differences in just four key proximate determinants: nuptiality, the postpartum non-susceptible period, contraception and abortion. Natural fecundibility is generally assumed to be constant between populations. This paper puts the theoretical and empirical case for a re-evaluation of that assumption, drawing on the under-utilized data on sexual activity collected in the Demographic Health Surveys (DHSs). Using data for married women in nine African countries, the analysis finds substantial population level differences in mean monthly coital frequency, which, if accurate, suggest an important demographic effect. There is a clear regional patterning to these differences, with levels of activity considerably lower among women in the West African populations included in the study than those from East and southern Africa. For West Africa in particular the data indicate the normality of exceptionally long periods of very infrequent or no intercourse by married women outside the period of postpartum abstinence. The findings challenge prevailing presumptions concerning susceptibility to pregnancy in marriage on which statistics for unmet need for family planning are derived. While doubts are raised over the precision of the sexual activity data used, the paper argues for the need for a greater effort to operationalize the 'proximate determinant of conception', not only for more accurate fertility modelling, but also as a planning tool for a more sensitive provision of family planning services in Africa.

Adolescent↗

Estimating mortality, morbidity and disability due to malaria among Africa's non-pregnant population.

The contribution of malaria to morbidity and mortality among people in Africa has been a subject of academic interest, political advocacy, and speculation. National statistics for much of sub-Saharan Africa have proved to be an unreliable source of disease-specific morbidity and mortality data. Credible estimates of disease-specific burdens are required for setting global and national priorities for health in order to rationalize the use of limited resources and lobby for financial support. We have taken an empirical approach to defining the limits of Plasmodium falciparum transmission across the continent and interpolated the distributions of projected populations in 1995. By combining a review of the literature on malaria in Africa and models of acquired functional immunity, we have estimated the age-structured rates of the fatal, morbid and disabling sequelae following exposure to malaria infection under different epidemiological conditions.

Adolescent↗

Changing population rates, policies and attitudes in Africa, the Middle East and South Asia.

This paper explores the relationship between population growth rates, government policies, and social attitudes in 3 regions: Africa, the Middle East, and South Asia. The comparative success of family planning programs in certain countries of South Asia (most notably India and Sri Lanka) can be partly ascribed to their long tradition of government leadership. In addition, families in those countries have strong incentives to educate their children. On the other hand, in North Africa and the Middle East, high levels of urbanization have had antinatalist effects, which are offset by very low levels of girls' schooling and of female employment outside the home. In Sub-Saharan Africa, high fertility is sustained by the structure of the family, with its tendency to separate reproductive decision-making from responsibility for child-rearing. In addition, governments there have had a comparatively weaker tradition in areas such as family behavior.

Africa↗

A survey of Simulium control in Africa.

It has become possible to control or even eradicate the Simulium fly vectors of Onchocerca volvulus, the causative organism of onchocerciasis. There are two vectors in Africa-namely, S. damnosum, characteristic of the rivers of West Africa, and S. neavei, which breeds on the carapaces of crabs in the streams of East Africa. The use of DDT applied to the water at a concentration as low as 0.1 p.p.m. for 30 minutes eliminates the larvae of Simulium. Such larvicidal methods have eradicated S. neavei from western Kenya and virtually eradicated S. damnosum from the Victoria Nile in Uganda. Excellent control sufficient to render the transmission of onchocerciasis almost negligible has been obtained at Léopoldville (Republic of the Congo) and in circumscribed areas in southern Chad, Northern Nigeria, and Sierra Leone. The following survey describes operational research on Simulium control carried out in Kenya, Uganda, the Congo, Chad, Nigeria, Ghana, Upper Volta and Sierra Leone.

Africa↗

Population history of north Africa: evidence from classical genetic markers.

After an intensive bibliographic search, we compiled all the available data on allele frequencies for classical genetic polymorphisms referring to North African populations and synthesized the data in an attempt to reconstruct the populations' demographic history using two complementary methods: (1) principal components analysis and (2) genetic distances represented by neighbor-joining trees. In both analyses the main feature of the genetic landscape in northern Africa is an east-west pattern of variation pointing to the differentiation between the Berber and Arab population groups of the northwest and the populations of Libya and Egypt. Moreover, Libya and Egypt show the smallest genetic distances with the European populations, including the Iberian Peninsula. The most plausible interpretation of these results is that, although demic diffusion during the Neolithic could explain the genetic similarity between northeast Africa and Europe by a parallel process of gene flow from the Near East, a Mesolithic (or older) differentiation of the populations in the northwestern regions with later limited gene flow is needed to understand the genetic picture. The most isolated groups (Mauritanians, Tuaregs, and south Algerian Berbers) were the most differentiated and, although no clear structure can be discerned among the different Arab- and Berber-speaking groups, Arab speakers as a whole are closer to Egyptians and Libyans. By contrast, the genetic contribution of sub-Saharan Africa appears to be small.

Africa, Northern↗

Fertility and family planning in southern and central Africa.

Southern Africa comprises a zone where the total fertility rate is below 6 births per woman. To the north is a ring of countries with higher fertility and relatively low contraceptive prevalence rates. The experience of South Africa, Botswana, and Zimbabwe, which have successful family planning programs, is compared with that of neighboring countries.

Adult↗

Release from native root herbivores and biotic resistance by soil pathogens in a new habitat both affect the alien Ammophila arenaria in South Africa.

Many native communities contain exotic plants that pose a major threat to indigenous vegetation and ecosystem functioning. Therefore the enemy release hypothesis (ERH) and biotic resistance hypothesis (BRH) were examined in relation to the invasiveness of the introduced dune grass Ammophila arenaria in South Africa. To compare plant-soil feedback from the native habitat in Europe and the new habitat in South Africa, plants were grown in their own soil from both Europe and South Africa, as well as in sterilised and non-sterilised soils from a number of indigenous South African foredune plant species. While the soil feedback of most plant species supports the ERH, the feedback from Sporobolus virginicus soil demonstrates that this plant species may contribute to biotic resistance against the introduced A. arenaria, through negative feedback from the soil community. Not only the local plant species diversity, but also the type of plant species present seemed to be important in determining the potential for biotic resistance. As a result, biotic resistance against invasive plant species may depend not only on plant competition, but also on the presence of plant species that are hosts of potential soil pathogens that may negatively affect the invaders. In conclusion, exotic plant species such as A. arenaria in South Africa that do not become highly invasive, may experience the ERH and BRH simultaneously, with the balance between enemy escape versus biotic resistance determining the invasiveness of a species in a new habitat.

Animals↗

Mefloquine compared with other malaria chemoprophylactic regimens in tourists visiting east Africa.

There is much confusion over which malaria chemoprophylaxis should be used in areas such as East Africa. We did two consecutive studies between 1985 and 1991 to assess the efficacy and side-effects of malaria chemoprophylaxis in short-term travellers to East Africa. All passengers returning from Kenya to Europe received an in-flight questionnaire and a second one three months later. Any report of documented malaria or of admission to hospital for possible side-effects was verified with the physician. 145 003 travellers completed questionnaires. Among the 139 164 who stayed in East Africa for less than one year, 296 cases of confirmed malaria were reported (275 due to P falciparum). In people who used no chemoprophylaxis, the incidence of falciparum malaria was 1.2% per month. Prophylactic effectiveness was 91% (95% Cl 85 to 94) for mefloquine, 82% (71 to 89) for pyrimethamine and sulfadoxine, 72% (56 to 82) for chloroquine plus proguanil, and 10 to 42% for chloroquine at various doses. Rates of side-effects, which were usually mild, were 18.8% for mefloquine users, 17.1% and 18.6% for chloroquine 300 mg and 600 mg base per week, respectively, 30.1% for chloroquine plus proguanil, and 11.7% for sulfadoxine and pyrimethamine. Mefloquine is significantly more effective than chloroquine plus proguanil for malaria prophylaxis in short-term tourists visiting East Africa and has a tolerance similar to that of chloroquine used alone.

Adult↗

Epidemiologists, social scientists, and the structure of medical research on AIDS in Africa.

The development of medical research on AIDS in Africa resembles earlier efforts to understand the epidemiology of TB and syphilis in Africa. In all three cases early research focused on why these diseases exhibited different epidemiological patterns in Africa than in the west. Early explanations of these differences focused on the peculiarities of African behavior, while largely excluding from vision a range of environmental factors. These parallels provide a framework for examining how western ideas about AIDS in Africa developed, the role of social scientists in the formation of these ideas, and how these initial perceptions shaped the subsequent development of AIDS research, encouraging a premature narrowing of research questions. The paper warns that, as in the histories of TB and syphilis research, this early closure may generate inadequate and inappropriate responses to the African AIDS epidemic and limit our understanding of the disease.

Acquired Immunodeficiency Syndrome↗

The influence of urbanisation on measures of Plasmodium falciparum infection prevalence in East Africa.

There is a growing interest in the effects of urbanisation in Africa on Plasmodium falciparum risks and disease outcomes. We undertook a review of published and unpublished literature to identify parasite survey data from communities in East Africa. Data were selected to represent the most reliable and contemporary estimates of infection prevalence and were categorised by urban or rural status using a number of approaches. We identified 329 spatially distinct surveys undertaken since 1980 in the sub-region of which 37 were undertaken in urban settlements and 292 in rural settlements. Overall rural settlements reported significantly higher parasite prevalence among children aged 0-14 than urban settlements (on average 10% higher infection rates; p<0.05). No urban settlements recorded parasite prevalence in excess of 75%. In areas of East Africa where climatic conditions are likely to support higher parasite transmission, the rural-urban difference was most marked. There was a significant trend towards documenting higher classes of parasite prevalence in rural compared to urban settlements (p<0.05) and the mean difference between rural and urban samples was 18% (p<0.001). These results further highlight the need to better define urban extents in Africa in order to capture the non-climatic determinants of infection and disease risk and provide a more informed approach to describing the burden of disease across the continent.

Adolescent↗

Determinants of suicide in the Transkei sub-region of South Africa.

BACKGROUND: South Africa has a history of traumatized citizens and is a society in transition. Suicidal behavior among the black population group in South Africa appears to be on the increase. Under the post-apartheid dispensation they are undergoing a lot of stresses especially in relation to their as yet unmet expectations and demands from the government. OBJECTIVE: To identify the possible determinants of suicide in the Transkei sub-region of South Africa. METHODS: Interviews with relatives of suicide victims, and analysis of victims' demographic, socioeconomic, and psychosocial data. RESULTS: Rural people (> 90%) were much more likely to commit suicide than urban dwellers (< 10%). Suicide notes were left by 13% of the victims. Hanging was the method of choice in 57%, gunshot in 30%, and poisoning in 13%. Among those who died by hanging and by gunshot injuries, males far outnumbered the females (82% and 89%, respectively). By contrast, females constituted the greater proportion of deaths by poisoning (75%). Apparent precipitating factors included economic hardship (87%), alcohol abuse (23%), health related issues (17%), marital problems (13%), and social disputes (10%). The uneducated (70%) and unemployed (64%) used hanging as the method of choice. The highly educated 5 (17%) were all employed, and used a firearm in committing suicide. Family disputes 5 (17%) and separation of parents from teenage children were recorded in 17% of the cases. CONCLUSION: Financial hardship was the main underlying reason, identified in 87% victims of suicide. To break this vicious cycle of unemployment, alcohol abuse, and poor health, a comprehensive poverty alleviation program along with community education could be an important step towards reducing suicides in the Transkei sub-region of South Africa.

Journal Article↗

Otavipithecus namibiensis, first Miocene hominoid from southern Africa.

We report here the discovery of a Miocene hominoid from Berg Aukas, Namibia, the first known from the African continent south of equatorial East Africa. This represents a major range extension of Miocene Hominoidea in Africa to latitude 20 degrees S. The holotype, a right mandibular corpus preserving the crowns of the P4-M3, partial crown and root of the P3, partial root of the canine, alveoli for all four incisors, and partial alveolus for the left canine, was found during paleontological explorations of karst-fill breccias in the Otavi region of northern Namibia. The mandible has unique characteristics that differentiate it from other middle Miocene hominoids of Africa and Eurasia and represents the only fossil evidence documenting a pre-australopithecine stage of hominoid evolution in southern Africa. Faunal analyses indicate that the breccia block containing the specimen accumulated during the latter part of the middle Miocene, about 13 +/- 1 Myr. Fauna from other breccia blocks at Berg Aukas are of diverse ages, including the earlier part of the middle Miocene, the upper Miocene, Plio-Pleistocene and Holocene.

Animals↗

Out of Africa: the slow train to australasia.

We used mitochondrial DNA (mtDNA) sequences to test biogeographic hypotheses for Patiriella exigua (Asterinidae), one of the world's most widespread coastal sea stars. This small intertidal species has an entirely benthic life history and yet occurs in southern temperate waters of the Atlantic, Indian, and Pacific oceans. Despite its abundance around southern Africa, southeastern Australia, and several oceanic islands, P. exigua is absent from the shores of Western Australia, New Zealand, and South America. Phylogenetic analysis of mtDNA sequences (cytochrome oxidase I, control region) indicates that South Africa houses an assemblage of P. exigua that is not monophyletic (P = 0.04), whereas Australian and Lord Howe Island specimens form an interior monophyletic group. The placement of the root in Africa and small genetic divergences between eastern African and Australian haplotypes strongly suggest Pleistocene dispersal eastward across the Indian Ocean. Dispersal was probably achieved by rafting on wood or macroalgae, which was facilitated by the West Wind Drift. Genetic data also support Pleistocene colonization of oceanic islands (Lord Howe Island, Amsterdam Island, St. Helena). Although many biogeographers have speculated about the role of long-distance rafting, this study is one of the first to provide convincing evidence. The marked phylogeographic structure evident across small geographic scales in Australia and South Africa indicates that gene flow among populations may be generally insufficient to prevent the local evolution of monophyly. We suggest that P. exigua may rely on passive mechanisms of dispersal.

Animals↗

Mobility and the spread of human immunodeficiency virus into rural areas of West Africa.

BACKGROUND: In eastern and southern Africa, the human immunodeficiency virus (HIV) epidemic appeared first in urban centres and then spread to rural areas. Its overall prevalence is lower in West Africa, with the highest levels still found in cities. Rural areas are also threatened, however, because of the population's high mobility. We conducted a study in three different communities with contrasting infection levels to understand the epidemiology of HIV infection in rural West Africa. METHOD: A comparative cross-sectional study using a standardized questionnaire and biological tests was conducted among samples in two rural communities of Senegal (Niakhar and Bandafassi, 866 and 952 adults, respectively) and a rural community of Guinea-Bissau (Caio, 1416 adults). We compared the distribution of population characteristics and analysed risk factors for HIV infection in Caio at the individual level. RESULTS: The level of HIV infection was very low in Niakhar (0.3%) and Bandafassi (0.0%), but 10.5% of the adults in Caio were infected, mostly with HIV type 2 (HIV-2). Mobility was very prevalent in all sites. Short-term mobility was found to be a risk factor for HIV infection among men in Caio (adjusted odds ratio (aOR) = 2.06; 95% CI: 1.06-3.99). Women from Caio who reported casual sex in a city during the past 12 months were much more likely to be infected with HIV (aOR = 5.61 95% CI: 1.56-20.15). Short-term mobility was associated with risk behaviours at all sites. CONCLUSIONS: Mobility appears to be a key factor for HIV spread in rural areas of West Africa, because population movement enables the virus to disseminate and also because of the particularly risky behaviours of those who are mobile. More prevention efforts should be directed at migrants from rural areas who travel to cities with substantial levels of HIV infection.

Adolescent↗