Adult Onchocerca volvulus from east and west Africa exhibit similar antigenicity with pooled sera from onchocerciasis patients.
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Africa, Eastern↗
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Cowpea flour: a potential ingredient in food products.
Cowpeas (Vigna unguiculata L. Walp) are an important grain legume in East and West African countries as well as in other developing countries. The U.S. is the only developed country producing large amounts of cowpeas. High protein (18 to 35%) and carbohydrate (50 to 65%) contents, together with an amino acid pattern complementary to that of cereal grains, make cowpeas potentially important to the human diet from a nutritional standpoint. Despite their potential as an inexpensive source of protein and energy, cowpeas are underutilized in the U.S. and other industrialized countries. A simple technology for preparing cowpea flour would stimulate increased consumption of this legume. This paper reviews the status of cowpea flour production technologies and uses of cowpea flour in various food products.
Africa, Eastern↗
Diagnostic evaluation of newly arrived asymptomatic refugees with eosinophilia.
BACKGROUND: Refugees may arrive for resettlement with asymptomatic parasitic infections, and eosinophilia may be the only clue to the presence of infection. Our aim was to determine the prevalence of eosinophilia and develop a standardized approach to the evaluation of asymptomatic refugees with eosinophilia. METHODS: We reviewed the medical records of refugees seen from October 1998 through May 2002 at Boston Medical Center. Data examined included age, country of origin, absolute eosinophil count, results of stool ova and parasite testing, and results of serological testing for Strongyloides stercoralis, Schistosoma species, and filaria. RESULTS: Eosinophilia--defined as an absolute eosinophil count of >or=450 cells/microL--was present in 266 (12%) of 2224 refugees. Patients with eosinophilia ranged in age from 2 months to 81 years and had arrived from Africa, Eastern Europe, Southeast Asia, South America, the Caribbean, and the Middle East. Absolute eosinophil counts ranged from 450 to 3224 cells/microL. Pathogens were identified in stool samples of 76 (29%) of 265 patients. Serological testing for S. stercoralis, Schistosoma species, and/or filaria was done for 120 (45%) of 266 patients. Results of serological testing were positive for S. stercoralis in 45 (39%) of 115 patients, for Schistosoma species in 15 (22%) of 67 patients, and for filaria in 18 (51%) of 35 patients. Serological evidence of parasitic infection was seen at all levels of eosinophilia and in patients with and without pathogens identified in their stool samples. CONCLUSIONS: Systematic evaluation for parasites in asymptomatic, newly arrived refugees with eosinophilia should include stool ova and parasite examination, serological examination for S. stercoralis for all patients, and serological examination for Schistosoma species and filaria in patients from regions where these organisms are endemic.
Adolescent↗
HIV type 1 strains from East and West Africa are intermixed in Sudan.
The genetic subtypes of HIV-1 in the Sudan epidemic have not been characterized. Here we report the partial sequencing and analysis of 30 strains collected from HIV-1-positive patients and blood donors in Khartoum in 1998 and 1999. From analysis of partial pol and env sequences, it was determined that 50% were subtype D and 30% were subtype C. Of interest, some subtype D clustered with those from East Africa whereas others joined subtype D from West Africa. Subtype A, subtype B, and three unique recombinants were also found, some partially unclassifiable. One unclassified strain matched another reported previously from the Democratic Republic of Congo. Sudan borders nine other African countries, and has suffered more than 20 years of civil strife with large population displacements. The intermixing of HIV-1 subtypes previously separated in Africa may be occurring there, with the potential to generate novel new strains by recombination.
Adult↗
Aflatoxin-albumin adducts in human sera from different regions of the world.
An immunoassay now permits the determination of human exposure to aflatoxin at an individual level and consequently allows a better assessment of the role of aflatoxin, and its interaction with hepatitis B virus infection, in the aetiology of liver cancer. Measurements of aflatoxin bound to serum albumin in children and adults from various African countries show that between 12 and 100% contain aflatoxin-albumin adducts, with levels up to 350 pg AFB1-lysine equivalent/mg albumin. In Thailand, lower levels and prevalence of this adduct were observed, while no positive sera were detected from France or Poland. Data are presented showing that exposure to this carcinogen can occur throughout life and the relevance of these observations to the understanding of the multifactorial aetiology of liver cancer in these countries is discussed.
Adult↗
Recent trends in the importation of malaria caused by Plasmodium falciparum into the United States from Africa.
National malaria surveillance data were reviewed in an analysis of the epidemiological impact of the transmission of chloroquine-resistant Plasmodium falciparum in Africa on malaria in the United States. Between 1975 and 1983, P. falciparum infections acquired by U.S. citizens who visited East Africa, especially Kenya, increased 21-fold. Estimated attack rates for P. falciparum per 100,000 U.S. travelers to Kenya rose from 21.2 cases in 1977 to 83.3 cases in 1982, a rise suggesting that the increase in imported malaria was not due to increased travel. The percentage of reported cases in U.S. citizens with P. falciparum infections acquired in East Africa who indicated having used chloroquine prophylaxis increased from 22.2% in 1978 to 75.8% in 1983; in contrast, no change in the reported use of chloroquine prophylaxis was observed in those infected in West Africa during the same period. These results suggest that chloroquine can no longer be considered a highly effective drug for prevention of malaria caused by P. falciparum in U.S. travelers to East Africa.
Africa, Eastern↗
Isolation and characterization of 115 street rabies virus isolates from Ethiopia by using monoclonal antibodies: identification of 2 isolates as Mokola and Lagos bat viruses.
There were 115 isolates of rabies viruses recovered by tissue culture technique from 119 animal brains collected in Ethiopia. By using 17 selected antinucleocapsid monoclonal antibodies (MAbs), 113 isolates were classic street rabies viruses (serotype 1). An isolate of feline origin (Eth-16) was a Mokola virus (serotype 3) and another isolate (Eth-58, obtained from a rabid dog) was serotype 2 (Lagos bat virus). None of the 16 antiglycoprotein MAbs used neutralized the Eth-16 isolate, whereas Eth-58 was neutralized by 1 (TERA543). Antirabies vaccines prepared from Pitman-Moore and Pasteur virus strains protected mice against homologous challenge, but neither was protective against the 2 rabies-related virus isolates. The isolation of Mokola and Lagos bat viruses from domestic animals in eastern Africa is of public and veterinary concern mainly due to lack of effective vaccines against these agents and the difficulty of proper diagnosis.
Animals↗
A biochemical key to adult members of the Anopheles gambiae group of species (Diptera: Culicidae).
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Africa, Eastern↗
Leishmaniasis in the Sudan Republic. 23. Sandflies (Phlebotomus) attracted to rodent-baited traps (Diptera: Psychodidae).
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Africa, Eastern↗
Chromosomal and protein evolution in morphologically similar species of Praomys sensu lato (Rodentia, Muridae).
Evidence of extensive chromosomal evolution in a biologically and economically important group of African murids of the Praomys/Mastomys complex was provided by examination of G- and C-band chromosomal data on P. coucha (2n = 32), P. fumatus (2n = 38), P. hildebrandti (2n = 32), P. jacksoni (2n = 28), P. misonnei (2n = 36), and P. cf. tullbergi (2n = 35). A coding system was developed for the chromosomal characters, and analyses were performed by a computer program to find the shortest tree with a minimum of 35 autosomal rearrangements (pericentric inversions, complex translocations, centric fusions, centric fissions, tandem fusions, euchromatic additions, and heterochromatic additions). The resulting phylogenetic hypothesis differs from traditionally accepted hypotheses regarding this complex group of rodents. The cytogenetic data show that 1) there is no support for the dichotomy of Mastomys/Praomys previously based on morphology, 2) the 2n = 32 species from eastern Africa (P. hildebrandti) is distinct from the 2n = 32 species from southern Africa (P. natalensis), and 3) there is a close association between P. jacksoni and P. cf. tullbergi. Polyacrylamide gel electrophoresis of liver membrane proteins demonstrated few differences in protein mobilities between species and even fewer between individuals of the same species taken from different habitats and localities in Kenya. Monoclonal antibodies produced against liver proteins of one species and tested for reactivity to other species confirmed the evolutionary similarity of species of this complex. This immunologic approach may provide a robust data set for future phylogenetic studies of muroid rodents.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Structure of African elephant populations.
The structure of elephant populations from east and south Africa has been analyzed by Georgiadis et al. (1994) on the basis of restriction site variation of mitochondrial DNA. They used F statistics based on identity by descent in tests for subdivision and reached the conclusion that there was a significant differentiation at the continental level, but that "populations were not significantly subdivided at the regional levels." The data were reanalyzed by Monte-Carlo permutation tests where population subdivision was tested by using F statistics based on partitioning the total haplotype diversity among populations. This resulted in identical conclusions at the continental level, but revealed in addition a significant subdivision at the regional level indicating haplotype frequency differences among the populations.
Africa, Eastern↗
Major-histocompatibility-complex variation in two species of cichlid fishes from Lake Malawi.
Lake Malawi in eastern Africa harbors > 500 endemic species of cichlid fishes, all of which are believed to have emerged from a single founding population in the past 2 Myr. Molecular characterization of differences among the species could provide important information about the nature of speciation in the period of adaptive radiation. Because of the close relationship, however, molecular variation among the species has been difficult to ascertain. In this communication, we provide evidence for extensive differences, in major-histocompatibility-complex (Mhc) class II genes, between two related species, Pseudotropheus zebra and Melanochromis auratus. We used specific primers to amplify and sequence intron 1 and exon 2 of the class II genes from 18 individuals. Although we found 20 different sequences among the 42 that we produced, there was not a single sequence shared by the two species. Thus the study suggests that different cichlid species of Lake Malawi have different profiles of class II alleles, presumably because the polymorphism present in the ancestral founding population segregated differentially into the various species. These results make Mhc genes an important tool for elucidating speciation.
Amino Acid Sequence↗
Estimating the rate of mother-to-child transmission of HIV. Report of a workshop on methodological issues Ghent (Belgium), 17-20 February 1992. The Working Group on Mother-to-Child Transmission of HIV.
PURPOSE: In the last 8 years, numerous cohort studies have been conducted to estimate the rate of mother-to-child transmission (MTCT) of HIV. Many of these have faced problems in data collection and analysis, making it difficult to compare transmission rates between studies. This workshop on methodological aspects of the study of MTCT of HIV-1 was held in Ghent (Belgium) in February 1992. STUDY SELECTION AND DATA EXTRACTION: Fourteen teams of investigators participated, representing studies from Central (five) and Eastern Africa (three), Europe (two), Haiti (one) and the United States (three). A critical evaluation of the projects was carried out, under four headings: (1) enrollment and follow-up procedures, (2) diagnostic criteria and case definitions, (3) measurement and comparison of MTCT rates and (4) determinants of transmission. RESULTS OF DATA ANALYSIS: Reported transmission rates ranged from 13 to 32% in industrialized countries and from 25 to 48% in developing countries. However, no direct comparisons could be made because methods of calculation differed from study to study. Based on this review, a common methodology was developed. Agreement was reached on definitions of HIV-related signs/symptoms, paediatric AIDS and HIV-related deaths. A classification system of children born to HIV-1-infected mothers according to their probable HIV infection status during the first 15 months of life, allowed the elaboration of a direct method of computation of the transmission rate and of an indirect method for studies with a comparison group of children born to HIV-seronegative mothers. This standardized approach was subsequently applied to selected data sets. CONCLUSIONS: The methodology can now be applied to all studies with sufficient follow-up and comparisons made between transmission rates. This step is essential for assessing determinants of transmission and for the development of a common approach for the evaluation of interventions aimed at reducing or interrupting MTCT of HIV.
Adult↗
Diversification and extinction patterns among Neogene perimediterranean mammals.
The best mammalian fossil record during the Neogene of Western Europe is that of the rodents, the most successful and diversified mammal order. The study of origination and extinction during the Neogene (24-3 Ma BP) in one of the best-documented areas, Spain and southern France, gives an insight into the dynamics of these communities and indicates the possible nature of the driving forces. Three main periods of time show a high rate of origination: the late Burdigalian (17.5 Ma BP), the early Vallesian (11.5-11 Ma BP) and the early Pliocene (4.2-3.8 Ma BP). Two of these high origination-rate periods are immediately followed by important extinction events during which all cohorts are deeply affected (11.5-11 Ma BP and 4.2-3.8 Ma BP). The most important extinction event seems to occur during the early Vallesian (11.5-11 Ma BP), which probably includes the middle/late Miocene boundary. At the Miocene/Pliocene boundary, and during the early Pliocene, the faunal turnover seems to become faster, inducing a strong decrease of the mean species duration. Whereas the main immigration event, which occurs at 17.5 Ma BP, can be related to other faunal migrations in terms of the closure of the Tethys, as it occurs also in eastern Africa and in southwest Asia, the middle/late Miocene boundary event may have been related to a period of ice growth in the Southern Hemisphere. The extinction event that affects the planktonic foraminifera at 12 Ma BP cannot be chronologically correlated to this southwestern European land-mammal extinction event, because the calibration of the marine fossil record during that time-span has to be precise. Some limited terrestrial faunal exchanges that occur during the Messinian between southwestern Europe and northwestern Africa do not deeply affect the general faunal dynamics. Both allochthonous cohorts of immigrants become rapidly extinct. Several endemic rodent faunas, indicating insular conditions, have been reported from the southern edge of the western European continent from the middle Miocene up to the Pliocene. All show low taxonomic diversity, strong endemism and short survival. Some of them, like those of the Gargano Islands during the late Miocene, underwent peculiar morphological changes and also speciation. The large number of rodent genera coevolving in the Gargano Islands is indicative of the large surface areas of these islands. The general geographic pattern of southwestern Europe during the Neogene may therefore correspond to a large continental province including Spain and southern France with some kind of fast-modifying archipelago on its southern rim.
Animals↗
Foot-and-mouth disease type O viruses exhibit genetically and geographically distinct evolutionary lineages (topotypes).
Serotype O is the most prevalent of the seven serotypes of foot-and-mouth disease (FMD) virus and occurs in many parts of the world. The UPGMA method was used to construct a phylogenetic tree based on nucleotide sequences at the 3' end of the VP1 gene from 105 FMD type O viruses obtained from samples submitted to the OIE/FAO World Reference Laboratory for FMD. This analysis identified eight major genotypes when a value of 15% nucleotide difference was used as a cut-off. The validity of these groupings was tested on the complete VP1 gene sequences of 23 of these viruses by bootstrap resampling and construction of a neighbour-joining tree. These eight genetic lineages fell within geographical boundaries and we have used the term topotype to describe them. Using a large sequence database, the distribution of viruses belonging to each of the eight topotypes has been determined. These phylogenetically based epidemiological studies have also been used to identify viruses that have transgressed their normal ecological niches. Despite the high rate of mutation during replication of the FMD virus genome, the topotypes appear to represent evolutionary cul-de-sacs.
Africa, Eastern↗
Genome analysis and phylogenetic relationships between east, central and west African isolates of Yellow fever virus.
Yellow fever virus (YFV), a reemerging disease agent in Africa and South America, is the prototype member of the genus Flavivirus. Based on examination of the prM/M, E and 3' non-coding regions of the YFV genome, previous studies have identified seven genotypes of YFV, including the Angolan, east/central African and east African genotypes, which are highly divergent from the prototype strain Asibi. In this study, full genome analysis was used to expand upon these genetic relationships as well as on the very limited full genome database for YFV. This study was the first to investigate genomic sequences of YFV strains from east and central Africa (Angola71, Uganda48a and Ethiopia61b). All three viruses had genomes of 10 823 nt in length. Compared with the prototype strain Asibi (from west Africa) they were approximately 25 % divergent in nucleotide sequence and 7 % divergent in amino acid sequence. Comparison of multiple flaviviruses in the N-terminal region of NS4B showed that amino acid sequences were variable and that west African strains of YFV had an amino acid deletion at residue 21. Additionally, N-linked glycosylation sites were conserved between viral genotypes, while codon usage varied between strains.
Africa, Central↗
Classification of the southern African sanga and east African shorthorned zebu.
Humped African cattle, which are differentiated into zebu and sanga types, have traditionally been classified as Bos indicus. This paper discusses existing evidence and presents new evidence supporting the classification of southern African sangas as Bos taurus and East African zebus as 'taurindicus'. Classification is based on karyotype, frequencies of DNA markers and protein polymorphisms. The Boran, an East African zebu, has an acrocentric Y chromosome typical of Bos indicus. The southern African sanga breeds have a submetacentric Y chromosome typical of Bos taurus. Frequencies of four DNA markers support the hypothesis that the Tuli, a southern African sanga, had taurine ancestors and the Boran had both taurine and indicine ancestors. Frequencies for several protein polymorphisms strongly suggest that southern African sangas have more in common with taurine than with indicine breeds, while East African zebus are an admixture of African taurine and Asian indicine breeds.
Africa, Eastern↗
Prevalence of dental fluorosis in Sudanese children from two villages with 0.25 and 2.56 ppm fluoride in the drinking water.
Dental fluorosis is endemic in Eastern Africa and a high prevalence has been found even in low-fluoride (approximately 0.5 ppm) areas. Substantial seasonal changes in the fluoride content of water have also been reported. The aim of the present study was to ascertain, through one year, the fluoride concentration in water from two underground reservoirs in Sudan, in Treit el Biga (TeB) and Abu Groon (AG), and to assess dental fluorosis in children aged 7-16 years who had been lifelong residents. The water in one of the reservoirs (TeB) was shown to have a low, very stable fluoride concentration (0.25 ppm SD 0.04) whereas the other (AG) had a tenfold higher, and slightly varying, fluoride concentration (2.56 ppm SD 0.26). Dental fluorosis was recorded on maxillary central incisors according to Dean's index. In TeB 91% of the children showed signs of dental fluorosis whereas in AG all children had fluorotic teeth. The Community Fluorosis Index in TeB and AG was 1.40 and 2.44, respectively. There was a significantly higher degree of fluorosis in boys than in girls in the low-fluoride area. In TeB, older boys tended to have more fluorosis than younger boys; the difference, however, was not statistically significant. No significant sex or age differences in fluorosis were found in AG. In both villages great inter-individual variations in dental fluorosis were recorded. The prevalence and severity of dental fluorosis in TeB was higher than that previously reported in areas with similar fluoride concentrations in the drinking water.
Adolescent↗