Genetic analysis of type O viruses responsible for epidemics of foot-and-mouth disease in North Africa. (1/263)

The nucleotide sequences of the 3' end of the capsid-coding region were determined for 30 serotype O foot-and-mouth disease (FMD) viruses isolated between 1987 and 1994 from outbreaks in North Africa and the Middle East. These sequences were compared with the previously published sequences of 9 field virus isolates from the Middle East and 5 vaccine virus strains, 3 of which originated from the Middle East (O1/Turkey/Manisa/69, O1/Sharquia/Egypt/72 and O1/Israel/2/85) and 2 from Europe (O1/Lausanne/Switzerland/65 and O2/Brescia/Italy/47). Cluster analysis of these sequences using the unweighted pair group mean average (UPGMA) method showed: (i) that the FMD viruses isolated from North Africa and the Middle East were very different from the classical European vaccine strains; (ii) that all the viruses isolated during the 1989-92 North African epidemic formed a cluster differing by no more than 6% from each other; (iii) a virus isolated in Libya in 1988 was unrelated to the aforementioned epidemic; and (iv) viruses from a second, less extensive epidemic, occurring in 1994, fell into yet another cluster.  (+info)

Estimating mortality, morbidity and disability due to malaria among Africa's non-pregnant population. (2/263)

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.  (+info)

Deaths within 90 days from starting renal replacement therapy in the ERA-EDTA Registry between 1990 and 1992. (3/263)

BACKGROUND: Patients who die within 90 days of commencing renal replacement therapy (RRT) may be recorded by some centres and not others, and hence data on mortality and survival may not be comparable. However, it is essential to compare like with like when analysing differences between modalities, centres and registries. It was decided, therefore, to look at the incidence of deaths within 90 days in the ERA-EDTA Registry, and to try to define the characteristics of this group of patients. METHODS: Between 1 January 1990 and 31 December 1992, 78 534 new patients started RRT in 28 countries affiliated to the ERA-EDTA Registry. Their mean age was 54 years and 31% were over 65 years old. Eighty-two per cent of the patients received haemodialysis (HD), 16% peritoneal dialysis (PD) and 2% had preemptive transplantation as first mode of treatment. RESULTS: From January 1990 to March 1993 the overall incidence of deaths was 19% and 4% of all patients died within 90 days from the start of RRT. Among those dying within 90 days 59% were over 65 years compared to 53% over 65 years in those dying beyond this time (P<0.0001). The modality of RRT did not influence the distribution of deaths before and after 90 days. Vascular causes and malignancy were more common in those dying after 90 days, while there were more cardiac and social causes among the early deaths. Mortality from social causes was twice as common in the elderly, who had a significantly higher chance of dying from social causes within 90 days compared to those aged under 65 years. The overall incidence of deaths within 90 days was 3.9% but there was a wide variation between countries, from 1.8% to 11.4%. Finally, patient survival at 2 years was markedly influenced in different age groups when deaths within 90 days were taken into account. CONCLUSIONS: The incidence of deaths within 90 days from the start of RRT was 3.9%, with a marked variation between countries ranging from 1.8% to 11.4%, which probably reflects mainly differences in reporting these deaths, although variable selection criteria for RRT may contribute. Deaths within 90 days were significantly more frequent in elderly patients with more early deaths resulting from cardiac and social causes, while vascular causes of death and malignancy were more common in those dying after 90 days. Patient survival analyses should take into account deaths within 90 days from the start of RRT, particularly when comparing results between modalities, countries and registries.  (+info)

Variation in short tandem repeats is deeply structured by genetic background on the human Y chromosome. (4/263)

Eleven biallelic polymorphisms and seven short-tandem-repeat (STR) loci mapping on the nonrecombining portion of the human Y chromosome have been typed in men from northwestern Africa. Analysis of the biallelic markers, which represent probable unique events in human evolution, allowed us to characterize the stable backgrounds or haplogroups of Y chromosomes that prevail in this geographic region. Variation in the more rapidly mutating genetic markers (STRs) has been used both to estimate the time to the most recent common ancestor for STR variability within these stable backgrounds and to explore whether STR differentiation among haplogroups still retains information about their phylogeny. When analysis of molecular variance was used to study the apportionment of STR variation among both genetic backgrounds (i.e., those defined by haplogroups) and population backgrounds, we found STR variability to be clearly structured by haplogroups. More than 80% of the genetic variance was found among haplogroups, whereas only 3.72% of the genetic variation could be attributed to differences among populations-that is, genetic variability appears to be much more structured by lineage than by population. This was confirmed when two population samples from the Iberian Peninsula were added to the analysis. The deep structure of the genetic variation in old genealogical units (haplogroups) challenges a population-based perspective in the comprehension of human genome diversity. A population may be better understood as an association of lineages from a deep and population-independent gene genealogy, rather than as a complete evolutionary unit.  (+info)

Mortality differentials among Israeli men. (5/263)

OBJECTIVES: This study examined differentials in mortality among adult Israeli men with respect to ethnic origin, marital status, and several measures of social status. METHODS: Data were based on a linkage of records from a 20% sample of the 1983 census to records of deaths occurring before the end of 1992. The study population included 72,527 men, and the number of deaths was 17,378. RESULTS: Differentials is mortality by origin show that mortality was higher among individuals of North African origin than among those of Asian and European origin. After allowance for several socioeconomic indicators, the excess mortality among North African Jews was eliminated. Substantial and consistent differences in mortality were found according to education, occupation, income, possession of a car, housing, and household amenities. Differentials among the elderly were markedly narrower than those among men younger than 70 years. CONCLUSIONS: Some sectors of Israeli society have higher risks of death than others, including, among the male population, these who are poor, less educated, unmarried, unskilled, out of the labor force, and of North African origin.  (+info)

Frequent association between alteration of the rdxA gene and metronidazole resistance in French and North African isolates of Helicobacter pylori. (6/263)

Mutations in the rdxA gene have been associated with the acquisition of resistance to metronidazole in Helicobacter pylori. This gene encodes an NADPH nitroreductase whose expression is necessary for intracellular activation of the drug. We wished to examine whether mutations in rdxA were present in resistant H. pylori isolates infecting either French or North African patients. We determined the complete nucleotide sequences of the rdxA genes from seven French and six North African patients infected with paired resistant and sensitive strains. Genotyping by random amplified polymorphic DNA analysis confirmed the close genetic relatedness of the susceptible and resistant isolates from individual biopsies. Eight French and five North African individual resistant strains were also studied. For the French strains, an alteration in rdxA most probably implicated in resistance was found in 10 cases (seven frameshift mutations, two missense mutations, and one deletion of 211 bp). One to three putative missense mutations were identified in four cases, and a missense mutation possibly not implicated in resistance was discovered in the last case. For the North African strains, an alteration in rdxA was found in eight cases (three frameshift mutations, three missense mutations, one deletion of 6 bp, and one insertion of a variant of IS605). Two strains contained putative missense mutations, and no change was observed in rdxA of the last strain. Thus, inactivation of the rdxA gene is frequently, but not always, associated with resistance to metronidazole in French and North African clinical isolates of H. pylori. In addition, a variety of alterations of rdxA are associated with the resistant phenotype.  (+info)

The development of a continuous quality control programme for strict sperm morphology among sub-Saharan African laboratories. (7/263)

Inter-technician and between-laboratory differences, especially during the evaluation of sperm morphology, have been a major cause of concern. The study aimed to develop an intensive training programme with intervals of continuous quality control assessments for sperm morphology. Twenty andrology laboratories from sub-Saharan Africa were invited to participate in a World Health Organization Special Programme of Research, Development and Research Training in Human Reproduction semenology workshop. Following intensive training in strict sperm morphololgy evaluation, a continuous quality control programme was introduced on a quarterly basis. At baseline, the mean (+/- SD) percentage difference reported between the participants and the reference laboratory reading was 33.50 +/- 11%. After training, the mean percentage difference had decreased to 14.32 +/- 5% at 3 months and to 5.00 +/- 5% at 6 months. Pairwise comparison of the differences at each evaluation time revealed the following: Baseline differences (pre-training) differed significantly from the differences at 3 months (P = 0.0002) as well as at 6 months after training (P = 0.007). The differences at 6 months did not differ significantly from those at 3 months (P = 0.27). Training of andrology technicians as well as continuous proficiency testing can be conducted on a national and international level with the support of a referring laboratory. Global quality control measurements in andrology laboratories should become mandatory, since these results indicate that continuous quality control for laboratory technicians can be highly successful.  (+info)

Genetic structure of north-west Africa revealed by STR analysis. (8/263)

We have analysed a large set of autosomal short tandem repeat (STR) loci in several Arabic and Berber-speaking groups from north-west Africa (ie Moroccan Arabs, northern-central and southern Moroccan Berbers, Saharawis, and Mozabites). Two levels of analysis have been devised using two sets of 12STR loci, (D3S1358, vWA, FGA, THO1, TPOX, CSF1PO, D8S1179, D21S11, D18S51, D5S818, D13S317 and D7S820) and 21 (the former set plus D9S926, D11S2010, D13S767, D14S306, D18S848, D2S1328, D4S243, F13A1, and FES/FPS). For each set, data for a number of external reference populations were gathered from the literature. Several methods of analysis based on genetic distances (neighbour-joining trees, principal coordinate analysis, boundary detection), as well as AMOVA, showed that genetic differentiation among NW African populations was very low and devoid of any spatial pattern. When the NW African populations were grouped according to cultural or linguistic differences, the partition was not associated with genetic differentiation. Thus, it is likely that Arabisation was mainly a cultural process. A clear genetic difference was found between NW African populations and Iberians, which underscores the Gilbraltar Straits as a strong barrier to genetic exchange; nonetheless, some degree of gene flow into Southern Iberia may have existed. NW Africans were genetically closer to Iberians and to other Europeans than to African Americans.  (+info)

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