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PubMed2003

Evolution and diversity of HIV-1 in Africa--a review.

The HIV/AIDS pandemic represents a major development crisis for the African continent, which is the worst affected region in the world. Currently, almost 30 of the 42 million people infected with HIV worldwide live in Africa. AIDS in humans is caused by two lentiviruses, HIV-1 and HIV-2, which entered the human population by zoonotic transmissions from at least two different African primate species. Extensive phylogenetic analyses of partial and full-length genome sequences have helped to gain insights into the evolutionary biology and population dynamics of HIV. One of the major characteristics of HIV is its rapid evolution, which has resulted in substantial genetic diversity amongst different isolates, the majority of which are represented in Africa. Genetic variability of HIV and any consequent phenotypic variation poses a significant challenge to disease control and surveillance in different geographic regions of Africa. This review focuses on the origins and evolution of HIV, current classification and diversity of HIV isolates in Africa and provides an extensive account of the geographic distribution of HIV types, groups, and subtypes in each of the 49 African countries. Numerous epidemiological studies have provided a picture of HIV distribution patterns in most countries in Africa, and these show increasing evidence of the importance of HIV-1 recombinants. In particular, this review highlights that our current understanding of HIV distribution in Africa is incomplete and inadequately represents the diversity of the virus, and underscores the need for ongoing surveillance.

Africa, Central↗
PubMed1993

Maternal mortality in Africa: 1980-87.

African women of reproductive age have the highest death risk from maternal causes of any women in the world. The lifetime chance of maternal death is 1 in 21 in Africa as compared to 1 in 54 in Asia, which ranks second. Using published data, this paper examines the level and correlates of maternal mortality ratio (MMR) in Africa. The data indicates that MMR greatly differs among the countries of Africa. High MMR is found in most countries of sub-Saharan Africa, while countries of Northern Africa are characterized by relatively low maternal death. Reasons for high MMR in sub-Saharan Africa are explored in detail. Analysis using multiple regression suggests that the MMR in Africa is strongly influenced by population size, crude birth rate (CBR), crude death rate (CDR), calorie supply as a percentage of requirements, access to safe water, and percentage of urban population. Some cultural and behavioral factors, such as female circumcision and infibulation, are also associated with a high MMR. Future programs aimed at reducing the maternal mortality in African countries may benefit from the findings of this study.

Adolescent↗
PubMed2006

Improving street food vending in South Africa: achievements and lessons learned.

Until the late 1990s there were limited scientific data on the microbiological quality and safety of street-vended foods in South Africa, while information was already available in other developing countries, including those within the African region. At that time street-vended foods were perceived as unsafe and street food vending in South Africa was regarded as a practice, which should be outlawed. The first comprehensively documented scientific research into the safety of street-vended foods in South Africa was carried out through university-based research. This research found that street food vendors in South Africa were capable of producing relatively safe foods, with low bacterial counts, although there was still a need for proper hygiene conditions and access to basic sanitary facilities. The Department of Health of South Africa, when coordinating an FAO Technical Cooperation Programme (TCP) project on Improving Street Foods in South Africa, drew similar conclusions. This article provides information of the efforts by universities and health authorities in South Africa towards improving the safety and promoting the sale of street-vended foods. It is shown that a successful transition from street food vending being perceived as a nuisance by health authorities can be made to these authorities promoting and improving street food vending instead.

Commerce↗
PubMed2001

Voluntary counseling and testing for couples: a high-leverage intervention for HIV/AIDS prevention in sub-Saharan Africa.

Most HIV infections in sub-Saharan Africa occur during heterosexual intercourse between persons in couple relationships. Women who are infected by HIV seropositive partners risk infecting their infants in turn. Despite their salience as social contexts for sexual activity and HIV infection, couple relationships have not been given adequate attention by social/behavioral research in sub-Saharan Africa. Increasingly studies point to the value of voluntary HIV counseling and testing (VCT) as a HIV prevention tool. Studies in Africa frequently report that VCT is associated with reduced risk behaviors and lower rates of seroconversion among HIV serodiscordant couples. Many of these studies point out that VCT has considerable potential for HIV prevention among other heterosexual couples, and recommend that VCT for couples be practiced more widely in Africa. However, follow-up in the area of VCT for couples has been extremely limited. Thus, current understandings from social/behavioral research on how couples in sub-Saharan Africa manage HIV risks as well as HIV prevention interventions to support couples' HIV prevention efforts have remained underdeveloped. It appears that important opportunities are being missed for preventing HIV infection, be it by heterosexual transmission or mother-to-child HIV transmission by mothers who have been infected by their partners. Based on an overview of documentation on VCT in sub-Saharan Africa, this paper proposes that increased attention to couples-focused VCT provides a high-leverage HIV prevention intervention for African countries. The second half of the paper indicates areas where VCT needs to be strengthened, particularly with respect to couples. It also identifies areas where applied social/behavioral research is needed to improve knowledge about how couples in sub-Saharan Africa deal with the risks of HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed2002

The epidemiology of yellow fever in Africa.

Yellow fever (YF) is still a major public heath problem, particularly in Africa, despite the availability of a very efficacious vaccine. The World Health Organization estimates that there are 200,000 cases of YF annually, including 30,000 deaths, of which over 90% occur in Africa. In the past 15 years, the number of YF cases has increased tremendously, with most of the YF activity in West Africa. This increase in YF activity is in part due to a breakdown in YF vaccination and mosquito control programs. Five genotypes of YF virus have been found in Africa, and each genotype circulates in a distinct geographical region. West Africa genotype I, found in Nigeria and surrounding areas, is associated with frequent epidemics, whereas the three genotypes in East and Central Africa are in regions where YF outbreaks are rare. Other factors, including genetic and behavioral variation among vector species, are also thought to play a role in the epidemiology of YF in Africa.

Aedes↗
PubMed1991

Theileria parva: influence of vector, parasite and host relationships on the epidemiology of theileriosis in southern Africa.

The protozoan parasite Theileria parva, transmitted by the ixodid tick Rhipicephalus appendiculatus, is the cause of East Coast fever (ECF) and the related syndromes of Corridor disease and January disease in cattle of eastern, central and southern Africa. It is likely that buffalo (syncerus caffer) are the natural host of T. parva. In eastern and southern Africa, there exists both buffalo-adapted and cattle-adapted T. parva. Disease caused by buffalo-adapted parasites is called Corridor disease, and that caused by cattle-adapted parasites is termed East Coast fever. In eastern Africa, it has been shown experimentally that buffalo-adapted T. parva can, after serial passage in cattle, become adapted to cattle, in which it can then be maintained and cause ECF. This adaptation has been termed transformation. The transformation of buffalo-adapted T. parva to a cattle-adapted parasite has not been reported in southern Africa, and ECF, eradicated from South Africa, Swaziland and southern Mozambique by 1960, has not reappeared in the subcontinent. This paper discusses the possible reasons for this, and hypothesizes that vector population dynamics and the susceptibility of the vector population to infection with T. parva are among the most important factors which influence the expression of ECF as a disease entity, and the likelihood of transformation occurring. It also considers the possibility that disappearance of ECF from southern Africa resulted from the extinction, as a result of vigorous control measures and unfavourable climatic conditions, of non-diapausing populations of R. appendiculatus that may have been introduced from eastern Africa with cattle imported in 1901.

Africa, Southern↗
PubMed1997

Molecular epidemiology of type 1 polioviruses from Africa.

The genetic relationships between type 1 polioviruses circulating in sub-Saharan Africa during the past decade have been investigated by partial genomic sequencing across the VP1/2A region of the polioviral genome. Sequencing templates were generated by single-step reverse transcription PCR amplification of the viral RNA using poliovirus-specific primers. Seven poliovirus genotypes, circulating in different geographical regions during different periods, were identified. Considerable genetic variation was exhibited by strains within several of these genotypes, indicative of sustained endemic transmission within individual countries. Two genotypes appear to be circulating in Africa at present; one major genotype, which has been in circulation since at least 1980, covers a wide geographical region and includes countries in western, central and southern Africa. Within this genotype are several smaller clusters, possibly representing strains in the process of evolving into new genotypes. The second genotype presently in circulation has been found only in Tanzania and Zambia to date, associated with a relatively small number of cases. Imported genotypes, introduced from the Middle East and the Indian subcontinent, have also recently been in circulation in eastern and central Africa. In South Africa, three genotypes, one unique to the country and the others imported from west Africa and the Middle East, co-circulated endemically between 1980 and 1985. A fourth genotype, introduced from countries to the north, displaced the endemic strains and continued to circulate until 1989. This study has generated a meaningful overview of the endemic circulation and regional transmission of type 1 polioviruses throughout sub-Saharan Africa.

Africa South of the Sahara↗
PubMed1999

Risk to tourists posed by wild mammals in South Africa.

BACKGROUND: One of South Africa's principal tourist attractions is the opportunity to encounter Africa's large mammals in the wild. Attacks by these mammals can be exceptionally newsworthy with potentially deleterious effects on tourism. Little is known about the risk of injury and death caused by wild mammals to visitors to South Africa's nature reserves. The aim of this study was to determine the incidence of fatal and nonfatal attacks on tourists by wild mammals in South Africa and to ascertain avoidable factors, if any. METHODS: Commercial press records covering all South African Newspapers archived at the Independent Newspapers' central library were systematically reviewed for a 10-year period, January 1988 to December 1997 inclusive, to identify all deaths and injuries to domestic and international tourists resulting from encounters with wild mammals in South Africa. All of these incidents were analyzed to ascertain avoidable factors. RESULTS: During the review period seven tourists, including two students from Thailand and a German traveler, were killed by wild mammals in South Africa. Three of the four deaths ascribed to lions resulted from tourists carelessly approaching prides on foot in lion reserves. A judicial inquiry found that the management of a KwaZulu-Natal Reserve was culpable for the remaining death. Tourist ignorance of animal behavior and flagrant disregard of rules contributed to the two fatalities involving hippopotami. The unusual behavior manifested by the bull elephant responsible for the final death, resulted from discomfort caused by a dental problem to this pachyderm. During the same period there were 14 nonfatal attacks on tourists, including five by hippo, three by buffalo, two by rhino, and one each by a lion, leopard, zebra and musth elephant. Only the latter occurred while the visitor was in a motor vehicle. Tourist ethological naivete and failure to determine the experience of trail guides prior to travel, resulted in inadvertent agonistic behavior, unnecessary risk-taking and avoidable injury. CONCLUSIONS: This retrospective study has shown that attacks on tourists by wild mammals in South Africa are an uncommon cause of injury and death. Sensible precautions to minimize this risk include remaining in a secure motor vehicle or adequately fenced precincts while in the vicinity of large mammals, rigidly observing nature reserve instructions, never approaching animals that appear ill, malnourished, displaying aggressive behavior traits or female wild mammals with young, and demanding adequately trained and experienced game rangers when embarking on walking trails. Any behavior that might be construed as antagonistic and which could provoke an attack by large mammals should be avoided (e.g., driving directly at a lion). Visitors need to be informed of classic signs of aggression, in particular in elephants, which will allow timely avoidance measures to be taken. The risk-enhancing effect of excessive alcohol intake is undesirable in the game reserve setting, as is driving at high speed after dusk in areas where hippos graze. Local advice on personal safety in wildlife reserves and the credentials of trail guides should be obtained from lodge or reserve management, tourism authorities or the travel industry prior to travel to game reserves.

Adolescent↗
PubMed2005

Diagnoses of HIV-1 and HIV-2 in England, Wales, and Northern Ireland associated with west Africa.

OBJECTIVES: To describe HIV diagnoses, including those of HIV-2 infection, made in England, Wales, and Northern Ireland (E,W&NI) among those probably infected in west Africa, and to consider whether there is evidence for ongoing heterosexual transmission within the United Kingdom. METHODS: Reports of new HIV diagnoses received at the Communicable Disease Surveillance Centre were analysed. Individuals probably infected in west Africa and those infected through heterosexual intercourse within the United Kingdom by a heterosexual partner infected in west Africa were included. RESULTS: Between 1985 and 2003 inclusive, 1324 individuals diagnosed and reported with HIV had probably been infected in west Africa, with 222 diagnoses made in 2003. 917 (69%) were HIV-1 infected and 52 (6%) HIV-2 or HIV-1/HIV-2 co-infected. For 355 (27%) the HIV type was not reported. The proportion of HIV-2 and HIV-1/HIV-2 infections varied by country of infection (p<0.001): ranging from the Gambia (11.7%-15.2%) to Nigeria (0.7%-1.0%). A further 130 individuals were probably infected through heterosexual intercourse within the United Kingdom by a heterosexual partner infected in west Africa. 89 (68%) were HIV-1 infected and three (2%) HIV-2 infected or HIV-1/HIV-2 co-infected. For 38 (29%) HIV type was not reported. CONCLUSION: The number of people infected with HIV in west Africa and diagnosed in E,W&NI has increased in recent years, and there is evidence of heterosexual transmission within the United Kingdom from people infected in west Africa. While numbers of HIV-2 diagnoses remain relatively low, an appreciable proportion of people infected in some west African countries and diagnosed in the United Kingdom may be HIV-2 positive, with implications for prognosis and treatment.

Adolescent↗
PubMed2005

[The tobacco problem in French-speaking Africa and regional perspectives of the French-speaking African tobacco observatory].

The tobacco problem is one which is both global and political. The epidemic and the growing smoking crisis in Africa is a menace to the health of our continent, with significant socio-economic repercussions to follow in the coming years. Approximately 1.1 billion people around the world smoke, and between now and the year 2025, this number will most likely increase to 1.6 billion. By 2030, 10 million tobacco-related deaths will have occurred, and for the most part those deaths will be concentrated in developing countries. The tobacco industry clearly lies at the heart of the development of the tobacco pandemic in the 20th century. Specifically, cigarettes have made tobacco a massively consumed product, constantly expanding and opening up new markets; the day before yesterday it was men, yesterday it was women and youth, and today it is the developing world. The strategy is identical: increase sales, and do goat a price which puts a heavy burden on the population's health. The industries turn themselves towards developing countries, and namely Africa, in order to compensate for their losses in the markets of the Northern Hemisphere at a time when the demand in these countries is decreasing. The industry's cynical strategy targets Africa as its strongest potential market for development, counting on an estimated increase in consumption of 16% over the next decade, according to WHO's recent World Tobacco Atlas. The illegal importation of cigarettes is a practice which is growing more and more within African countries, with a well-structured African network for smuggling. Smuggled cigarettes are even more toxic with very elevated levels of nicotine and tar. Sponsorship as well as direct and indirect advertising are rapidly developing in all kinds of formats, with a proliferation of aggressive advertising messages targeting African populations with cynicism, manipulation, the complicity of smuggling in broad daylight, and disrespect for the law, while exploiting all of the themes which promote tobacco use to the target audiences (youth, women, the poorest groups). Everyday the tobacco industry recruits new African smokers to replace those who die. The future of the industry is represented by about 8 out of 10 people who began smoking before the age of 18 years old. It was imperative to establish a Tobacco Observatory in Francophone Africa (OTAF) in order to resituate the African tobacco situation, contribute to the development of the French-speaking nations in Africa, and to make known and increase awareness of its needs, its initiatives, and its actions across the world, and finally to effectively fight against tobacco and the industry's practices. One year after OTAF was established in Bamako thanks to the consolidated efforts of all its members and support of the French League against Cancer and the International Union against Cancer, OTAF OTAF is an independent entity whose mission is to gather, analyse and disseminate information on all aspects of tobacco with the objective of soliciting and supporting public health activities and interventions. It is a reference centre for Francophone Africa and a technical advisory group for the public authorities on tobacco issues. OTAF's work is counted upon to inform the public authorities on the most effective measures to use in the fight against tobacco. OTAF's duty is to promote activities which protect the health of young people and non-smokers, and communicate on the harmful effects of tobacco and the tobacco industry's practices. The goal is to organise a fight against tobacco based on solid, scientific data of the highest level of quality. OTAF is the only Francophone African surveillance organisation for monitoring the tobacco epidemic, and the practices, schemes and methods of the tobacco industry which are known to be dishonest Today, OTAF is a unique reference centre as far as the fight against tobacco is concerned in Francophone Africa. It is a partner in a number of projects with the French League against Cancer, the International Union against Cancer, and the International Union for Health Promotion and Education, among others. The success of OTAF has been crowned by a trophee having been awarded by WHO and an honorary degree signed by WHO's Director General.

Africa, Northern↗
PubMed2005

Vitamin A deficiency and child survival in sub-Saharan Africa: a reappraisal of challenges and opportunities.

BACKGROUND: Children with vitamin A deficiency have higher risk of morbidity and mortality than vitamin A-sufficient children. Estimates on the potential child survival benefits of vitamin A deficiency control are needed for policy and program advocacy. OBJECTIVE: To determine the current prevalence of children at risk for vitamin A deficiency in sub-Saharan Africa in order to estimate the potential child-survival benefits of effective and sustained policies and programs for the control of vitamin A deficiency in this region. METHODS: Estimates of the prevalence of vitamin A deficiency generated in 1998, data from 11 nationally representative vitamin A deficiency surveys conducted in sub-Saharan Africa between 1997 and 2003, and the measured effects of vitamin A deficiency on child mortality were combined to estimate the prevalence of children at risk for vitamin A deficiency in sub-Saharan Africa and the potential child-survival benefits of effective and sustained policies and programs for the control of vitamin A deficiency in this region. RESULTS: Our analysis shows that in the absence of effective and sustained policies and programs for the control of vitamin A deficiency, an estimated 42.4% of children 0 to 59 months of age in sub-Saharan Africa (43.2 million children) are at risk for vitamin A deficiency. Such effective and sustained policy and program action for the control of vitamin A deficiency can bring about a potential 25% reduction in mortality in children 0 to 59 months with respect to 1995 mortality levels (i.e., before the onset of large-scale vitamin A supplementation programs in sub-Saharan Africa). CONCLUSIONS: Effective and sustained control of vitamin A deficiency has the potential to be among the most cost-effective and high-impact child-survival interventions in sub-Saharan Africa. A stronger political commitment and a more appropriate level of investment in the effective control of vitamin A deficiency could make a large contribution toward the attainment of the Millennium Development Goal for the reduction of child mortality rates by two-thirds between 1990 and 2015. Among the many challenges that Africa will need to face in the coming years, vitamin A deficiency is one that can be overcome. The need is urgent, and the solutions are known, effective, and affordable.

Africa South of the Sahara↗
PubMed1988

Seroepidemiology of human immunodeficiency viruses in Africa.

The first generation of serological tests for anti-HIV-1 gave so many false positives with African sera that it was wrongly postulated that the virus was endemic in Africa. As there is no simian or other virus sufficiently closely related to HIV-1 as to suggest a recent common ancestor, the evolution of HIV-1 is obscure and there is no current evidence to support the hypothesis of an African origin. However, the similarity of HIV-2 to SIV and its geographical distribution do suggest an evolution of this virus in west Africa. The earliest anti-HIV-1 positive serum was from a subject in Kinshasa in 1959. Seroprevalence rose in pregnant women in Kinshasa from 0.25% in 1970, to 3.0% in 1980 and 5.7% in 1986. When two sexually promiscuous groups are compared, seropositivity rose sharply in female prostitutes in Nairobi from 4% in 1981, to 59% in 1984 and 64% in 1986, a curve which is approximately parallel to, but three years later than that of homosexual males in San Francisco. In central and east Africa, HIV-1 is now epidemic from Congo to Kenya and from Uganda to Zimbabwe. In west Africa, both HIV-2 and HIV-1 are epidemic: seroprevalence of HIV-2 is highest in southern Senegal, Guinea-Bissau and Côte d'Ivoire: HIV-1 has the highest frequency in Côte d'Ivoire and Ghana. HIV-2 has not been reported, and HIV-1 is pre-epidemic in Africa north of the Sahara, Nigeria, Angola, Mozambique and southern Africa, being found at significant frequency only in female prostitutes, patients with STD, or, in Morocco and South Africa only, in male homosexuals. Seroprevalence is greatest in female prostitutes and patients with STD: infection is more frequent in urban than in rural populations, except in Uganda. The peak frequency is at 30-34 yr in males and 20-24 yr in females. Other groups at risk are infants born to infected mothers, and those requiring blood transfusions, especially pre-school children, patients with sickle-cell disease and pregnant women. The doubling time for seropositivity is about one year in the sexually active age range in some populations. Even at existing seroprevalence, decimation or worse of the most productive age groups is inevitable during the next few years in certain countries.(ABSTRACT TRUNCATED AT 400 WORDS)

AIDS Serodiagnosis↗
PubMed1984

Virus-associated lymphomas, leukaemias and immunodeficiencies in Africa.

The relationship between viruses and naturally occurring cancers, such as hepatocellular carcinoma and genital cancers, is of great importance to Africa. On the other hand, lymphomas, leukaemias and immunodeficiencies, although of less immediate public health importance, constitute an area of outstanding interest for research and their association with the Epstein-Barr virus (EBV) and the newly discovered human retroviruses merits world-wide attention. EBV-related malignancies in Africa include both Burkitt's lymphoma (BL) and nasopharyngeal carcinoma (NPC). Whether X-linked polyclonal lymphoproliferations exist in Africa remains an open question. The interrelationship between EBV, holoendemic malaria and genetic factors (oncogenes) has been deciphered in recent years, to make BL a kind of Rosetta stone for the understanding of multistage carcinogenesis. Although the role of EBV in the causation of NPC is not well understood, the viral capsid antigen (VCA) IgA test already allows both early detection of NPC in high-incidence areas and differential diagnosis in low-incidence areas. The question whether an EBV vaccine would be of value in African countries, in relation to EBV-associated malignancies, remains an open one. The diseases associated with the recently discovered human retroviruses (human T-lymphocyte leukaemia viruses: HTLVs) represent a new area for both research and public health assessment. Limited information is available today on the geographical distribution, age prevalence and association with disease in Africa of the different members of the retrovirus family (HTLV-1, HTLV-2, LAV/HTLV-3). The proportion of HTLV-related T-cell malignancies in different parts of Africa as well as the importance of immunodeficiencies caused by the different members of the retrovirus family remain to be determined. Typical acquired immunodeficiency syndrome (AIDS) appears to exist in Central Africa, especially Zaire, and HTLVs could be of public health importance if they cause severe forms of viral, bacterial or parasitic diseases through impairment of cell-mediated immunity. Africa, is and will long remain a continent of crucial importance with regard to the role of viruses in human malignancies and especially in haematopoietic proliferative disorders.

Africa↗
PubMed1998

The early history of tuberculosis in central East Africa: insights from the clinical records of the first twenty years of Mengo Hospital and review of relevant literature.

SETTING: Mengo Hospital, in present day Kampala, Uganda, 100 years ago. OBJECTIVE: To determine the presence of tuberculosis in the Bagandan population of central East Africa and elsewhere in Africa at the time of early explorations by Europeans. DESIGN: The case records kept by Albert Cook for two decades beginning in 1897, 35 years after the first visit of Speke to this region, were reviewed for evidence of tuberculosis among Bagandans. Writings of other contemporary medical observers were reviewed for evidence of tuberculosis in pre- and early-colonial Africa. RESULTS: Well documented cases of tuberculosis were observed by Cook beginning in 1897. A minimum total of 93 cases of tuberculosis were included in 26 806 admissions to Mengo Hospital from 1897 through 1916. No secular trend in the prevalence of tuberculosis among patients admitted was apparent. A review of the prior literature concerning tuberculosis in precolonial Africa suggests that tuberculosis may have been present in several regions prior to European exploration, but was probably absent elsewhere. CONCLUSIONS: The concept of all of Africa and all of the people of Africa as virgin soil for tuberculosis is rooted in an archaic Eurocentric view of Africa, and cannot be supported today by available data.

Africa↗
PubMed1985

Hematologically and genetically distinct forms of sickle cell anemia in Africa. The Senegal type and the Benin type.

Patients with sickle cell anemia vary in the hematologic and clinical features of their disease, in part because of variability in the presence of linked and unlinked genes that modify the expression of the disease. The hemoglobin S gene is strongly linked to three different haplotypes of polymorphic endonuclease-restriction sites of the beta-like gene cluster (genes in the vicinity of the beta-globin gene)--one prevalent in Atlantic West Africa, another in central West Africa, and yet another in Bantu-speaking Africa (equatorial, East, and southern Africa). We have studied the differences in the hematologic characteristics of patients with sickle cell anemia from the first two geographical areas. We find that the Senegalese (Atlantic West Africa) patients have higher levels of hemoglobin F, a preponderance of G gamma chains in hemoglobin F, a lower proportion of very dense red cells, and a lower percentage of irreversibly sickled cells than those from Benin (central West Africa). We interpret these data to mean that the gamma-chain composition and the hemoglobin F level are haplotype linked and that the decrease in the percentage of dense cells and irreversibly sickled cells is secondary to the elevation in the hemoglobin F level. Patients with sickle cell anemia in the New World probably correspond to various combinations of these types, in addition to the still hematologically undefined haplotype associated with sickle cell anemia in the Bantu-speaking areas of Africa.

Adult↗
PubMed2004

The migration of physicians from sub-Saharan Africa to the United States of America: measures of the African brain drain.

BACKGROUND: The objective of this paper is to describe the numbers, characteristics, and trends in the migration to the United States of physicians trained in sub-Saharan Africa. METHODS: We used the American Medical Association 2002 Masterfile to identify and describe physicians who received their medical training in sub-Saharan Africa and are currently practicing in the USA. RESULTS: More than 23% of America's 771 491 physicians received their medical training outside the USA, the majority (64%) in low-income or lower middle-income countries. A total of 5334 physicians from sub-Saharan Africa are in that group, a number that represents more than 6% of the physicians practicing in sub-Saharan Africa now. Nearly 86% of these Africans practicing in the USA originate from only three countries: Nigeria, South Africa and Ghana. Furthermore, 79% were trained at only 10 medical schools. CONCLUSIONS: Physician migration from poor countries to rich ones contributes to worldwide health workforce imbalances that may be detrimental to the health systems of source countries. The migration of over 5000 doctors from sub-Saharan Africa to the USA has had a significantly negative effect on the doctor-to-population ratio of Africa. The finding that the bulk of migration occurs from only a few countries and medical schools suggests policy interventions in only a few locations could be effective in stemming the brain drain.

Journal Article↗
PubMed2006

Increased levels of soluble CD40L in African tick bite fever: possible involvement of TLRs in the pathogenic interaction between Rickettsia africae, endothelial cells, and platelets.

The pathophysiological hallmark of spotted fever group rickettsioses comprises infection of endothelial cells with subsequent infiltration of inflammatory cells. Based on its ability to promote inflammation and endothelial cell activation, we investigated the role of CD40L in African tick bite fever (ATBF), caused by Rickettsia africae, using different experimental approaches. Several significant findings were revealed. 1) Patients with ATBF (n = 15) had increased serum levels of soluble CD40 ligand (sCD40L), which decreased during follow-up. 2) These enhanced sCD40L levels seem to reflect both direct and indirect (through endothelial cell activation involving CX3CL1-related mechanisms) effects of R. africae on platelets. 3) In combination with sCD40L, R. africae promoted a procoagulant state in endothelial cells by up-regulating tissue factor and down-regulating thrombomodulin expression. 4) Although the R. africae-mediated activation of platelets involved TLR2, the combined procoagulant effects of R. africae and sCD40L on endothelial cells involved TLR4. 5) Doxycycline counteracted the combined procoagulant effects of R. africae and sCD40L on endothelial cells. Our findings suggest an inflammatory interaction between platelets and endothelial cells in ATBF, involving TLR-related mechanisms. This interaction, which includes additive effects between sCD40L and R. africae, may contribute to endothelial inflammation and hypercoagulation in this disorder.

Adult↗
PubMed2006

The potential impact of male circumcision on HIV in Sub-Saharan Africa.

BACKGROUND: A randomized controlled trial (RCT) has shown that male circumcision (MC) reduces sexual transmission of HIV from women to men by 60% (32%-76%; 95% CI) offering an intervention of proven efficacy for reducing the sexual spread of HIV. We explore the implications of this finding for the promotion of MC as a public health intervention to control HIV in sub-Saharan Africa. METHODS AND FINDINGS: Using dynamical simulation models we consider the impact of MC on the relative prevalence of HIV in men and women and in circumcised and uncircumcised men. Using country level data on HIV prevalence and MC, we estimate the impact of increasing MC coverage on HIV incidence, HIV prevalence, and HIV-related deaths over the next ten, twenty, and thirty years in sub-Saharan Africa. Assuming that full coverage of MC is achieved over the next ten years, we consider three scenarios in which the reduction in transmission is given by the best estimate and the upper and lower 95% confidence limits of the reduction in transmission observed in the RCT. MC could avert 2.0 (1.1-3.8) million new HIV infections and 0.3 (0.1-0.5) million deaths over the next ten years in sub-Saharan Africa. In the ten years after that, it could avert a further 3.7 (1.9-7.5) million new HIV infections and 2.7 (1.5-5.3) million deaths, with about one quarter of all the incident cases prevented and the deaths averted occurring in South Africa. We show that a) MC will increase the proportion of infected people who are women from about 52% to 58%; b) where there is homogenous mixing but not all men are circumcised, the prevalence of infection in circumcised men is likely to be about 80% of that in uncircumcised men; c) MC is equivalent to an intervention, such as a vaccine or increased condom use, that reduces transmission in both directions by 37%. CONCLUSIONS: This analysis is based on the result of just one RCT, but if the results of that trial are confirmed we suggest that MC could substantially reduce the burden of HIV in Africa, especially in southern Africa where the prevalence of MC is low and the prevalence of HIV is high. While the protective benefit to HIV-negative men will be immediate, the full impact of MC on HIV-related illness and death will only be apparent in ten to twenty years.

Africa South of the Sahara↗