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At least 19 recordsLinked to original sources

PubMed2001

Dental caries trends in 5 to 6 year-old and 11 to 13 year-old children in two UNICEF designated regions: Sub-Saharan Africa, and Middle East and North Africa, 1970-2000.

The purpose of this study was to do a systematic review of published caries epidemiology studies in two UNICEF defined regions, Sub-Sahara Africa, and the Middle-East and North Africa that contain 63 developing countries. On-line searches were made of articles listed in Medline using PubMed to investigate trends in dental caries in 5 to 6 year-old, and 11 to 13-year-old children using defined inclusion criteria. Of 493 listed publications, 70 fulfilled the inclusion criteria. The percentage caries rates and mean dmft, as well as mean DMFT scores, were plotted against study year. Non-significant percentage caries prevalence trends were downward in Sub-Saharan Africa for both 5-6 year-olds and 11-13 year-olds while in Middle-East and North Africa caries prevalence remained constant over the 30-year review period in both age groups. Mean dmft scores significantly diminished in 5-6 year-olds during the study period (y = 200-0.1x, P = 0.05) in Sub-Saharan Africa but the scores remained constant in the Middle-East and North Africa. Mean DMFT scores remained constant in 11-13 year-olds in both Sub-Saharan Africa and the Middle-East and North Africa. When the mean dmft and DMFT scores per carious mouth were calculated both age groups in Sub-Saharan Africa showed clear reductions, that for 11 to 13 year-olds was statistically significant (y = 170-0.084x, P = 0.014). In the Middle-East and North Africa the trends in the two age groups remained unchanged.

Adolescent↗

PubMed2001

Rickettsia africae, a tick-borne pathogen in travelers to sub-Saharan Africa.

BACKGROUND: African tick-bite fever occurs after contact with ticks that carry Rickettsia africae and that parasitize cattle and game. Sporadic reports suggest that this infection has specific clinical and epidemiologic features. METHODS: We studied patients who were tested for a rickettsial disease after returning from a visit to Africa or Guadeloupe. To assess the value of the microimmunofluorescence assay, Western blotting, and cross-adsorption assays, we compared the results of these tests in 39 patients in whom African tick-bite fever had been confirmed by the polymerase-chain reaction assay, cell culture, or both; 50 patients with documented R. conorii infection; and 50 blood donors. These diagnostic criteria were then applied to 376 additional patients who had returned from southern Africa and 2 who had returned from Guadeloupe and whose serum was being tested for rickettsial disease. RESULTS: In the 39 patients with direct evidence of R. africae infection, the combination of microimmunofluorescence assay, Western blotting, and cross-adsorption assays showing antibodies specific for R. africae had a sensitivity of 0.56; however, each test had a positive predictive value and a specificity of 1.0. An additional 80 patients were found to have an R. africae infection on the basis of these serologic criteria. Infections with R. africae were acquired by visitors to 11 African countries and Guadeloupe. The illness was generally mild and was characterized by a rash in 46 percent of the patients; the rash was usually maculopapular or vesicular and rarely purpuric. Ninety-five percent of patients had an inoculation eschar or eschars, and 54 percent of these patients had multiple eschars, a finding that is unusual in patients with rickettsial infection. CONCLUSIONS: In this series, R. africae was the cause of nearly all cases of tick-bite rickettsiosis in patients who became ill after a trip to sub-Saharan Africa.

Adolescent↗

PubMed2002

Seroepidemiology of Rickettsia africae infection in Norwegian travellers to rural Africa.

Rickettsia africae is the causative agent of African tick bite fever (ATBF), an acute febrile illness frequently accompanied by inoculation eschars, regional lymphadenitis, myalgia and severe headache. Recently, ATBF has been recognized as an emerging health problem for international travellers to rural sub-Saharan Africa. To estimate the incidence, risk factors for and proportion of symptomatic cases of travel-associated R. africae infection, we performed a seroepidemiological study of 152 first-time Norwegian travellers to rural areas in sub-Equatorial Africa. Seropositivity was based on the detection of specific antibodies to R. africae in microimmunofluorescence and/or Western blotting assays. Thirteen (8.6%) travellers were seropositive to R. africae. Eight (62%) seropositive travellers reported symptoms consistent with ATBF; of these, 2 had received antirickettsial therapy. Using multiple logistic regression, the following factors were found to be significantly associated with seropositivity: hunting as the purpose of travel [odds ratio (OR) 10.1; 95% confidence interval (CI) 1.5-69; p=0.019] and stay in rural areas of > 7 d (OR 6.0; 95% CI 1.5-24; p=0.012). This first seroepidemiological study on travel-associated R. africae infection suggests that the infection may be common in international travellers to rural sub-Saharan Africa but that most cases are asymptomatic or clinically mild and self-limited.

Adolescent↗

PubMed1998

Outbreak of Rickettsia africae infections in participants of an adventure race in South Africa.

African tick-bite fever, caused by Rickettsia africae and transmitted by Amblyomma ticks, is an emerging rickettsiosis in southern Africa. Because of increased tourism to this area, several cases in tourists have been reported recently. We report 13 cases of R. africae infection diagnosed in France that occurred in competitors returning from an adventure race in South Africa and compare our data with previously reported findings. Most of our patients presented with fever, headache, multiple inoculation eschars, and regional lymphadenopathies, but only 15.4% had a cutaneous rash. Diagnosis was confirmed either by isolation of R. africae from an eschar biopsy specimen or by serological methods, including cross-adsorption between R. africae and Rickettsia conorii. The purpose of this study was to raise physicians' awareness of R. africae infections in an attempt to facilitate the rapid diagnosis and treatment of imported African tick-bite fever in developed countries.

Adult↗

PubMed2005

Trichinella britovi etiological agent of sylvatic trichinellosis in the Republic of Guinea (West Africa) and a re-evaluation of geographical distribution for encapsulated species in Africa.

In West Africa, Trichinella infection was documented in humans and animals from Senegal in the 1960s, and the biological characters of one isolate showed a lower infectivity to domestic pigs and rodents when compared with that of a Trichinella spiralis pig isolate from Europe. To identify the Trichinella species present in West Africa, a survey was conducted in a total of 160 wild animals in the Republic of Guinea. Three Viverridae, one true civet (Viverra civetta) and two African palm civets (Nandinia binotata) from the Fouta Djallon Massif, Pilimini Subprefecture, were found positive by artificial digestion of muscle samples. Trichinella larvae from these three viverrids were identified as Trichinella britovi and no difference was detected in three examined sequences from these African isolates and the reference strain of T. britovi from Europe, indicating common ancestry, an historically continuous geographic distribution, and recent isolation for African and European populations. The detection of T. britovi in West Africa modifies our knowledge about the distribution of encapsulated species of Trichinella in Africa. Thus, Trichinella nelsoni is now considered to have a distribution limited to the Eastern part of the Afrotropical region from Kenya to South Africa. This provides a plausible explanation for the presence of Trichinella T8 in Namibia and South Africa, and further suggests that T. britovi could be the Trichinella species circulating among wild animals of Northern Africa.

Animals↗

PubMed1999

Genetic evidence of an early exit of Homo sapiens sapiens from Africa through eastern Africa.

The out-of-Africa scenario has hitherto provided little evidence for the precise route by which modern humans left Africa. Two major routes of dispersal have been hypothesized: one through North Africa into the Levant, documented by fossil remains, and one through Ethiopia along South Asia, for which little, if any, evidence exists. Mitochondrial DNA (mtDNA) can be used to trace maternal ancestry. The geographic distribution and variation of mtDNAs can be highly informative in defining potential range expansions and migration routes in the distant past. The mitochondrial haplogroup M, first regarded as an ancient marker of East-Asian origin, has been found at high frequency in India and Ethiopia, raising the question of its origin. (A haplogroup is a group of haplotypes that share some sequence variations.) Its variation and geographical distribution suggest that Asian haplogroup M separated from eastern-African haplogroup M more than 50,000 years ago. Two other variants (489C and 10873C) also support a single origin of haplogroup M in Africa. These findings, together with the virtual absence of haplogroup M in the Levant and its high frequency in the South-Arabian peninsula, render M the first genetic indicator for the hypothesized exit route from Africa through eastern Africa/western India. This was possibly the only successful early dispersal event of modern humans out of Africa.

Africa↗

PubMed2004

Prevalence of stroke survivors in rural South Africa: results from the Southern Africa Stroke Prevention Initiative (SASPI) Agincourt field site.

BACKGROUND AND PURPOSE: The importance of stroke in low-income regions such as sub-Saharan Africa has recently been emphasized. However, little is known about the burden of stroke in sub-Saharan Africa. We investigated the prevalence of stroke survivors in the Agincourt Health and Population Unit, a demographic surveillance site in the rural northeast of South Africa. METHODS: Census workers asked household informants 2 screening questions for stroke during the annual census. If either question was answered positively, a clinician visited individuals aged > or =15 years to confirm the likely diagnosis of stroke. We performed a detailed assessment and defined stroke according to the World Health Organization criteria. RESULTS: A total of 42 378 individuals were aged > or =15 years. There were 982 positive responses to the questionnaire, and we examined 724 individuals (74%). We identified 103 strokes (crude prevalence, 243/100 000). After adjustment for those we did not examine, the prevalence was 300/100 000 (95% CI, 250 to 357). Sixty-six percent of stroke survivors needed help with at least 1 activity of daily living (Segi age-standardized prevalence, 200/100 000). CONCLUSIONS: Stroke prevalence in rural South Africa is higher than previously documented in Africa but lower than in high-income countries. However, the prevalence of stroke survivors requiring help with at least 1 activity of daily living is already at high-income country levels. South Africa suffers from a huge burden of HIV/AIDS and diseases of poverty and violence and now faces the challenge of adapting its health systems to face the coming epidemic of vascular disease.

Adolescent↗

PubMed1987

Mental health in Africa: I. The extent of mental health problems in Africa today. An update of epidemiological knowledge.

This paper is concerned with steadily developing knowledge of the epidemiology of some psychiatric disorders in sub-Saharan Africa. The diversity of 'Black Africa' is noted, and preconceptions about African psychiatry briefly discussed. Problems of sociological versus clinical philosophies are also mentioned. Early estimates of prevalence of psychiatric disorder in black Africa were universally low, being based on hospital data. More recent studies, sampling diverse populations, suggest a burden of psychiatric morbidity in black Africa which is not dissimilar to that found in more developed countries, and some studies suggest that rates in Africa may even be higher than in developed countries.

Africa↗

PubMed2005

Molecular biodiversity of cassava begomoviruses in Tanzania: evolution of cassava geminiviruses in Africa and evidence for East Africa being a center of diversity of cassava geminiviruses.

Cassava is infected by numerous geminiviruses in Africa and India that cause devastating losses to poor farmers. We here describe the molecular diversity of seven representative cassava mosaic geminiviruses (CMGs) infecting cassava from multiple locations in Tanzania. We report for the first time the presence of two isolates in East Africa: (EACMCV-[TZ1] and EACMCV-[TZ7]) of the species East African cassava mosaic Cameroon virus, originally described in West Africa. The complete nucleotide sequence of EACMCV-[TZ1] DNA-A and DNA-B components shared a high overall sequence identity to EACMCV-[CM] components (92% and 84%). The EACMCV-[TZ1] and -[TZ7] genomic components have recombinations in the same genome regions reported in EACMCV-[CM], but they also have additional recombinations in both components. Evidence from sequence analysis suggests that the two strains have the same ancient origin and are not recent introductions. EACMCV-[TZ1] occurred widely in the southern part of the country. Four other CMG isolates were identified: two were close to the EACMV-Kenya strain (named EACMV-[KE/TZT] and EACMV-[KE/TZM] with 96% sequence identity); one isolate, TZ10, had 98% homology to EACMV-UG2Svr and was named EACMV-UG2 [TZ10]; and finally one isolate was 95% identical to EACMV-[TZ] and named EACMV-[TZ/YV]. One isolate of African cassava mosaic virus with 97% sequence identity with other isolates of ACMV was named ACMV-[TZ]. It represents the first ACMV isolate from Tanzania to be sequenced. The molecular variability of CMGs was also evaluated using partial B component nucleotide sequences of 13 EACMV isolates from Tanzania. Using the sequences of all CMGs currently available, we have shown the presence of a number of putative recombination fragments that are more prominent in all components of EACMV than in ACMV. This new knowledge about the molecular CMG diversity in East Africa, and in Tanzania in particular, has led us to hypothesize about the probable importance of this part of Africa as a source of diversity and evolutionary change both during the early stages of the relationship between CMGs and cassava and in more recent times. The existence of multiple CMG isolates with high DNA genome diversity in Tanzania and the molecular forces behind this diversity pose a threat to cassava production throughout the African continent.

Base Sequence↗

PubMed2005

Repellent efficacy of four commercial DEET lotions against Amblyomma hebraeum (Acari: Ixodidae), the principal vector of Rickettsia africae in southern Africa.

African tick bite fever, caused by Rickettsia africae, is an emerging zoonotic infection in rural sub-Saharan Africa and the French West Indies. We tested the repellent efficacy of four commercial diethyl-3-methylbenzamide (DEET) lotions against Amblyomma hebraeum Koch, the principal vector of R. africae in southern Africa, by using a human bioassay in which repellent-treated fingers were presented to questing tick nymphs hourly for 4h. Three lotions with 19.5, 31.6 and 80% DEET concentrations, respectively, had a repellent efficacy of > or =90% at 1h post-application, of > or =77% at 2h post-application and of <70% during the rest of the experiment. By contrast, a lotion with 2% DEET plus 1% citronella oil provided only a 59% repellency at 1h post-application, with a drop to <22% during the following hours. Hourly negative control trials repelled <5% of tick attacks. Our results suggest that commercial repellents containing > or =19.5% DEET provide a significant but short-lasting protection against questing A. hebraeum ticks.

Administration, Topical↗

PubMed1995

Comparative population structuring of molecular and allozyme variation of Drosophila melanogaster Adh between Europe, west Africa and east Africa.

Restriction enzyme molecular variation in Drosophila melanogaster Adh was compared between three natural populations from Europe, West Africa and East Africa. The frequency distribution of silent variation in the slow allele was compatible with the neutral model in all three samples. The number of haplotypes in East Africa was significantly higher than in the other two populations. The largest divergence, as measured by Fst, was between the East African population and a group made up from the West African, the European, and previously studied American populations. We suggest that a split first occurred within African populations at least 44000 years ago. European populations separated from West Africa more recently, between the last glacial maximum and the post-glacial optimum, 18,000 to 8,000 years ago. We suggest that this species was domesticated recently relative to human evolution, possibly with the advent of agriculture. Population differentiation with respect to the two allozymes, fast and slow, does not follow the geographical pattern of silent variation. It opposes European to both African populations, and probably results from selection for adaptation to alcohol in recent temperate populations.

Africa↗

PubMed1996

The epidemiology and prophylaxis of hepatitis B in sub-Saharan Africa: a view from tropical and subtropical Africa.

There are approximately 50 million chronic carriers of hepatitis B virus (HBV) in Africa, with a 25% mortality risk. In sub-Saharan Africa, carrier rates range from 9-20%. Many studies have suggested that HBV transmission in Africa occurs predominantly in childhood, by the horizontal rather than the perinatal route. The exact mode of transmission is uncertain but probably involves percutaneous infection through saliva or traces of blood, as well through unsterile needles, tribal scarification, and other possible vehicles. Compared with adult HBsAg carriers in the Far East, those in Africa have a low rate of HBeAg positivity, which may account for the relatively low rates of perinatal infection. It is also possible that African infants are less susceptible to perinatal HBV infection compared with their Asian counterparts. Alternatively, it may be that African infants are indeed infected with HBV at birth but, for genetically determined reasons, have persistently negative tests for a number of years until the virus is reactivated. In view of the high HBV carrier rates in the general population, universal immunisation of all infants is recommended. Ways of incorporating the hepatitis B vaccine into the Expanded Programme on Immunisation in each country are being evaluated.

Africa South of the Sahara↗

PubMed1987

[Malaria and pregnancy. Comparative study of Central Africa and Western Africa].

The transmission of malaria occurs mainly in and following the rainy season (intermittent transmission) in the Sahelian zone of Africa. On the other hand in rainy Equatorial Africa the transmission of malaria is continuous so that it is stable and can give rise to continuous antigenic stimulation in pregnant women which in turn gives rise to passive early high level immunity in the infant. 150 couples of mother and cord blood and 206 placentae were studied. We found 12.1% of carriers of blood parasites in the blood as compared with 1.6% in the cord bloods (exclusively P. falciparum). Where there were medium quantities of fluorescent antibodies in the mothers 74% could be found in the cord serum. Two methods were used to measure antimalarial antibodies as evidence of infection and also partly protective: the first method was indirect immunofluorescence, and the second was co-electrosyneresis. There was a narrow correlation between the level of precipitant antibodies in the mothers who were infected and in the fetal cord bloods. Anatomo-pathological examination of the placenta showed that 2 out of the 206 had parasites in them, 9 out of the 206 had fibrin deposits around the villi and 6.8% of the placentae showed lesions of malaria. On the other hand, in West Africa there was very little maternal morbidity as evidence by fever and anaemia, or of fetal morbidity. There was no single case of congenital malaria. The levels of the plasma indices in the towns could be explained because of prophylaxis which was both controlled and uncontrolled.

Africa, Central↗

PubMed2003

Diabetes in Africa. Epidemiology of type 1 and type 2 diabetes in Africa.

Until recently, there was a paucity of data on the epidemiology of diabetes mellitus in Africa. Over the past decade, information on the prevalence of type 2 diabetes has increased, albeit still limited, but there is still a lack of adequate data on type 1 diabetes in sub-Saharan Africa (SSA). For type 2 diabetes, although the prevalence is low in some rural populations, moderate and even high rates have been reported from other countries. In low diabetes prevalence populations, the moderate to high rates of impaired glucose tolerance is a possible indicator of the early stage of a diabetes epidemic. Diabetes prevalence is higher in urban, migrant and African-origin populations living abroad. There is evidence for a significant association with preventable and modifiable risk factors viz. adiposity, known diabetes, physical activity; but a dearth of data on the impact of dietary and genetic factors. For type 1 diabetes, the limited available data suggest that in SSA the frequency is low and that age of onset occurs later than in the western world. There is evidence for the role of genetic and immunological factors in its pathogenesis. The impact of HIV/AIDS on projected estimates for diabetes prevalence in Africa needs to be established.

Africa↗

PubMed1995

Guidelines for the management of hypertension at primary health care level. Hypertension Society of Southern Africa, endorsed by the Medical Association of South Africa and the Medical Research Council.

OBJECTIVE: To outline rational and cost-effective comprehensive management of hypertension by health care professionals in a primary care setting. OUTCOMES: Control of hypertension with a target blood pressure (BP) of systolic 140 - 159 mmHg, diastolic 90 - 94 mmHg, with minimal or no drug side-effects. Reduce BP in the elderly and those with severe hypertension gradually. Stricter BP control is required for patients with end-organ damage, coexisting risk factors, diabetes mellitus. Extensive data including many randomised controlled trials showed the benefit of controlling hypertension. This evidence is reported in Opie L. H. and Steyn K., Rationale for the hypertension guidelines for primary care in South Africa, S Afr Med J 1995; 85: 1325-1338. VALUES: To treat as many of the untreated hypertensive patients as possible, using rational and cost-effective care. Cost-effectiveness and access to therapy are major issues. BENEFITS, HARMS AND COSTS: Reduction in stroke, cardiac failure, renal failure and coronary artery disease. The major precautions and contraindications to each antihypertensive drug recommended are listed. The financial costs of the drugs are considered. RECOMMENDATIONS: Correct BP measurement procedure. identification of blood pressure levels for appropriate management. Evaluation of other cardiovascular risk factors and their influence on when to treat hypertension. Lifestyle modification and patient education for all patients. Drug therapy: first line--low-dose diuretics; second line--reserpine or beta-blockers or ACE inhibitors or calcium channel blockers; third line--hydralazine or prazosin or another second-line drug. Drug treatment and referral or specific cases (pregnancy, diabetes mellitus, severe hypertension). VALIDATION: Developed by the Hypertension Society of Southern Africa Executive Committee and co-opted persons during 1995, with added input from HSSA members at the National Congress. Endorsed by the Medical Association of South Africa.

Adult↗

PubMed1989

Dental educational trends in Africa with special reference to southern Africa.

Sub-Saharan Africa is experiencing a population growth unparalleled in the rest of the world. This is placing severe constraints on health care education and especially on dental education. The 16 or so dental schools in this part of the continent cannot train sufficient dentists for Africa's needs. In consequence, many states are developing training programmes for auxiliaries in an endeavour to meet their oral health care needs. Emphasis is placed on community involvement in the various dental curricula and it has been suggested that the African dentist should also be equipped to render basic medical care. At most schools the dental course is a 5-5 1/2 year programme with considerable emphasis on the basic medical sciences so that a student can easily be trained to act in a dual capacity as dentist and basic physician. This will, however, require the availability of more operating auxiliaries to meet the basic oral care demands of the population. In the dental course at South African schools the major portion of curriculum time in the clinical years is occupied by restorative and prosthetic dentistry. Although this is still appropriate, caries prevention and the availability of operating auxiliaries may soon make this approach redundant. Integrated courses in which the advanced disciplines of dentistry receive more emphasis seem to offer exciting prospects for the future, especially if the benefits of such integrated courses are fully exploited.

Africa↗

PubMed1993

A host-parasite list of the haematozoa of domestic poultry in sub-Saharan Africa and the isolation of Plasmodium durae Herman from turkeys and francolins in South Africa.

An annotated host-parasite list of the blood parasites of domestic poultry in sub-Saharan Africa is presented. This list contains the haematozoa found in domestic waterfowl (ducks, geese and muscovies) and phasianids (turkey, fowl and peafowl). In South Africa Plasmodium durae was isolated from 4 out of 8 backyard turkeys, from 3 out of 26 Swainson's francolins and from 1 redwing francolin, but not from 20 helmeted guineafowls and 9 greywing francolins. This points at Swainson's and redwing francolins as being the main natural hosts of P. durae in South Africa. The increase in the period of prepatency after intramuscular subinoculation as compared with the intravenous route was found to correspond to that of a 1,000 fold dilution of an intravenous inoculum of parasitized blood. This delay was not due to an intervening cycle of exoerythrocytic schizogony, but to large numbers of the injected erythrocytes apparently not finding their way into the circulation of the new host.

Animals↗

PubMedDate not supplied

PVO / NGO initiatives, Africa. Society for Women and AIDS in Africa (SWAA), Mauritania.

Society for Women and AIDS in Africa (SWAA), Mauritania, uses a multi-sectoral approach to raise awareness of the HIV/AIDS pandemic and provide assistance when needed. SWAA believes that in order to have an impact on women and development in their country they must address issues of health, education, and society. To these ends they have created a special center to provide health care and counseling to HIV-positive women and their children; they conduct health and general education sessions geared towards women; and they have formed local chapters of SWAA throughout Mauritania to provide support and information to women within their own communities. SWAA has also taken on a mass education campaign which includes the production of flyers, educational materials, and public service announcements for radio and television. For more information, please contact Mme. Sana Mint Abass, President, SWAA/Mauritanie, BP 118, Nouakchott, Mauritanie; tel: +222 564 69 (office), +222 524 04 (home); fax: +222 599 26.

Adolescent↗