A preliminary analysis of emigration determinants in Mexico, Central America, northern South America and the Caribbean.
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Americas↗
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Results for “Northern America”
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[World health-related indicators].
Many of the statistics given in this report are estimates based on tentative data and on that extent are not reliable in a strict sense. But the picture they present of gross differences in demographic and social characteristics, in vital statistics, and in resources of medical manpower and hospital beds between major areas of the world is real. More than half of the people of the world live in South Asia and East Asia; population density is highest in Western Europe; and highest rates of population growth are in Middle America and Tropical South America. In Europe less than one-third of the population are aged under 20 years, whereas more than half the population are aged under 20 im Middle and Tropical South America and the Carribbean, in Africa and in South Asia. Urbanization is high in Temperate South America, Northern America, Northern and Western Europe, and Oceania. The daily dietary energy supply per person is 50% higher in Northern America, Europe, USSR, and Ocenia than in Africa (excluding Southern Africa, South and East Asia. The Gross National Product in Northern America is 10 times higher than in Tropical South America and 30 to 40 times higher than in Western Middle and Eastern Africa and in Middle South and South East Asia. Crude birth rates are close to three times higher in Africa, Middle America and South Asia than in Europe, North America and USSR. Differences in crude death rates are less--rates in Western, Middle and Eastern Africa are double these of America Europe, USSR and Oceania. The Expectation of Life is over 70 years for Northern America, Europe, USSR and Oceania. It is under 50 years for Western, Middle and Eastern Africa. In all areas the expectation of life at birth has increased--by up to 10 years--in the past quarter century. Infant mortality is less than 20 per 1 000 in Northern and Western Europe and Northern America. It is over 100 in Africa and South Asia. Number of physicians range from 25 per 10 000 population in USSR to less than 1 per 10 000 in Western, Middle and Eastern Africa. There are over 100 hospital beds per 10 000 population in USSR and in Northern and Western Europe, less than 10 per 10 000 in Western Africa, Middle South Asia and South East Asia.
Age Factors↗
[Ethnicity and pluralism in Northern America: a comparison of Canadian and U.S. perspectives].
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Americas↗
Population structure.
This paper reviews recent new trends in population structure in the world and its major regions in order to access the determinants of those trends and explore issues regarding the recent and projected changes in the age structure of population and the relationships of those changes to social and economic development. In particular, the paper compares the change in age structure projected by the Population Division of the UN Secretariat in its most recent 3 series--namely, those completed in 1984, 1986, and 1988. By and large, the most recent UN assessment projects that a larger proportion of the world population will be aged 60 and over in 2000 and 2025 than was previously estimated. Those changes in projections can be observed for the world and for the more developed countries as a whole, and for the regions of Africa, Latin America, Northern America, East Asia, Europe, and Oceania. While the recommendations of the International Conference on Population called attention to the importance of changes in population structure, this paper recommends urgent government action in planning social programs for the aged because of the greater eminence of population aging in many settings. The case of Japan is used to illustrate the growing importance of increases in life expectancy as a determinant of age structure changes (in relation to fertility decline), a point that is reinforced through a cruder decomposition of UN estimates and projections for several European countries.
Africa↗
Profile of the foreign-born population in the United States.
"This report profiles the growth of the foreign-born population in the United States during the 1980s. The socioeconomic and demographic characteristics of this changing population and the fertility differences found among the various immigrant groups are highlighted. This paper will also show the similarities and differences between the foreign-born and native-born population for various demographic and economic indicators.... The data presented here are from the 1980 census and the April 1983, June 1986, and June 1988 Current Population Surveys (CPS). Detailed tabulations are shown for five major regions contributing most of the immigrants to the United States--Asia, Latin America, Europe, Northern America, and the Soviet Union."
Americas↗
The origin and diversification of Galapagos mockingbirds.
Evolutionary radiations of colonists on archipelagos provide valuable insight into mechanisms and modes of speciation. The apparent diversification of Galapagos mockingbirds (Nesomimus) provoked Darwin's initial conception of adaptive radiation, but the monophyly of this historically important exemplar has not been evaluated with molecular data. Additionally, as with most Galapagos organisms, we have a poor understanding of the temporal pattern of diversification of the mockingbirds following colonization(s) from source populations. Here we present a molecular phylogeny of Galapagos and other mockingbird populations based on mitochondrial sequence data. Monophyly of Galapagos mockingbirds was supported, suggesting a single colonization of the archipelago followed by diversification. Our analyses also indicate that Nesomimus is nested within the traditional genus Mimus, making the latter paraphyletic, and that the closest living relatives of Galapagos mockingbirds appear to be those currently found in North America, northern South America, and the Caribbean, rather than the geographically nearest species in continental Ecuador. Thus, propensity for over-water dispersal may have played a more important role than geographic proximity in the colonization of Galapagos by mockingbirds. Within Galapagos, four distinct mitochondrial DNA clades were identified. These four clades differ from current taxonomy in several important respects. In particular, mockingbirds in the eastern islands of the archipelago (Española, San Cristóbal, and Genovesa) have very similar mitochondrial DNA sequences, despite belonging to three different nominal species, and mockingbirds from Isabela, in the west of the archipelago, are more phylogenetically divergent than previously recognized. Consistent with current taxonomy is the phylogenetic distinctiveness of the Floreana mockingbird (N. trifasciatus) and close relationships among most mockingbirds from the central and northern region of the archipelago (currently considered conspecific populations of N. parvulus). Overall, phylogeographic patterns are consistent with a model of wind-based dispersal within Galapagos, with colonization of more northerly islands by birds from more southern populations, but not the reverse. Further radiation in Galapagos would require coexistence of multiple species on individual islands, but this may be prevented by relatively limited morphological divergence among mockingbirds and by lack of sufficient habitat diversity in the archipelago to support more than one omnivorous mimid.
Animals↗
Molecular phylogeny of Coriaria, with special emphasis on the disjunct distribution.
Coriaria, which has the most conspicuously disjunct distribution of the flowering plants, is distributed in four separate areas of the world. The phylogenetic relationships of 12 Coriaria species collected from the representative disjunct areas were inferred by comparing 2416 bp of the combined data set of rbcL (a large subunit of ribulose 1,5-bisphosphate carboxylase/oxygenase) and matK (maturase K) genes. The phylogenetic tree shows that the Chile-Papua New Guinea-New Zealand-Pacific islands species and the Central America-northern South America species form a sister group, and the Eurasian clade is more basal to them. The divergence time between the Eurasian group and the other species was estimated as 63 or 59 million years ago using rbcL and matK molecular clocks, respectively. These results do not support previously proposed hypotheses which explain the disjunct distribution on the basis of continental drift but suggest that the distribution pattern was formed by several geographical migrations and separations in the Cenozoic.
Cucurbitaceae↗
Socio-demographic determinants of stopping smoking from Italian population-based surveys.
Frequency and determinants of smoking cessation were analysed using data from two Italian National Health Surveys, conducted in 1983 and 1986-87 on samples of 89,753 and 77,155 individuals respectively, randomly selected within strata of region of residence, size of the municipality and of the household, in order to be representative of the general Italian population. Overall stopping ratios or "quit ratios" (i.e., ratios between ex- and ever-smokers) were 20.5% for males and 9.0% for females in the 1983 survey, and rose to 23.2 and 11.9% respectively in 1986-87. With reference to age, stopping rates were slightly higher for females than for males below age 35, but considerably higher for males in each subsequent age group, particularly in middle age. Ratios were apparently higher for the most recent survey for both sexes and each subsequent age group. After standardisation for age, "quit ratios" in both sexes were directly related with education. Cessation of smoking was more common in northern (and richer) areas of the country, and positively associated with the prevalence of smoking-related chronic diseases. The major, and most discouraging, finding from these analyses is the absolute low rate of stopping in Italy as compared to northern America or northern Europe, although some positive tendency towards increasing cessation was evident between the early and the late 1980s. These tendencies, together with some recent drops in smoking prevalence in younger women, first observed after decades of increase, indicate a change at least in attitudes towards reporting smoking, and hence social acceptance of the habit.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Frequency of a mutated CCR-5 allele (delta32) among Italian healthy donors and individuals at risk of parenteral HIV infection.
The aim of this study was to assess the frequency of a truncated allele of the CCR-5 gene (delta32) in Italy, and address its possible role in parenteral HIV transmission, as well as its influence in HIV-associated disease progression. In 371 unrelated seronegative healthy blood donors the delta32 allele frequency was 0.047; this figure was significantly different from those reported in northern America and northern Europe populations. However, delta32 allele frequency in healthy individuals did not differ significantly from that found in 54 seronegative drug users (0.065), 98 seronegative hemophiliacs (0.051), and 81 seropositive hemophiliacs (0.049). Although in seropositive hemophiliacs the wt/delta32 heterozygous genotype was associated with a trend to a slower decline in CD4+ cell counts, its presence did not seem to influence disease progression, as comparable delta32 allele frequency frequencies were found among progressing (0.042) and nonprogressing (0.111) patients. These data do not seem to support a protective role of the delta32 allele in preventing HIV infection through the parenteral route, or in influencing the natural history of the disease in this particular risk category, although the delta32 heterozygous state was associated with lower plasma viremia levels. On the other hand, the finding of non-syncytium-inducing HIV strains in the majority of delta32 heterozygous seropositive patients suggests that its presence could not be a major factor in driving a switch toward more cytopathic, T-tropic HIV strains through selective pressure in coreceptor usage.
Alleles↗
Antigenic variants of the Soldado virus (Nairovirus, Bunyaviridae) isolated in different parts of the world.
Antigenic analysis of 9 strains of the Soldado virus, originating from seven different countries of Central and Northern America, Africa, Northern Europe and of the Pacific area was carried out by means of complement fixation (CF) and immunodiffusion (ID) tests. Three strains isolated from Ornithodoros (A.) capensis, including the reference Trinidad strain, were found to be related within the same relatively heterogeneous sub-group C, being characteristic for the New World. Five other strains isolated from Ornithodoros (A.) maritimus were classified to form an another, much more homogeneous subgroup M, characteristic for the Old World (related to the Ireland strain). The South Africa strain, isolated form Ornithodoros (A.), probably capensis, could not be classified in either of the above two subgroups. Thus, the Soldado virus in fact represents a complex of more or less closely related strains, but not a single virus.
Antigens, Viral↗
[Re-emergence of Venezuelan equine encephalitis virus in French Guiana. Apropos of 1 confirmed case].
Venezuelan equine encephalitis (VEE) is a mosquito-borne viral disease that occurs in equine species and in man. The strains can be grouped epidemiologically into two major categories: enzootic and epizootic. Enzootic strains cause sporadic human disease and are not associated with disease among equines. These strains are found throughout Florida. Central America, northern South America and Brazil. Epizootic strains are associated with enormous morbidity and mortality in equine species. In man, VEE virus infections are largely asymptomatic and in children and young adults there is an increased risk of encephalitis and dead. We report the first case in French Guiana of Venezuelan equine encephalitis. Clinical examination and biological studies showed encephalitis, interstitial pneumonia and acute liver failure. Despite an adequate symptomatic treatment, the young patient died five days after her admission in multiple organ dysfunction syndrome. Diagnosis is establishing by virologic test: VEE virus is isolated from the blood. These example of re-emerging infectious disease vividly illustrate that we remains vulnerable and emphasizes the need for an active surveillance system.
Blood↗
A genotype of hepatitis D virus that occurs in northern South America.
Hepatitis D virus (HDV) is the cause of an unusually severe form of liver disease with distinct histologic features (morula cell) that occurs throughout northern South America and certain other areas of the world. Clinical studies of HDV disease worldwide indicate that there is, in fact, a wide variation in pathogenesis, and the reasons for these differences are presently unknown. One possible explanation is that factors associated with the viral genotype are determinants of HDV pathogenesis. In this study, nucleic acid sequences were determined for three different northern South American HDV isolates which were obtained from individuals with severe disease or a family history of severe disease, in areas that are hyperendemic for this disease pattern. The sequences of these three isolates are very similar to one another but only distantly related to other published HDV sequences. Comparison of the sequence of a semiconserved region from a total of 14 isolates indicates that there are at least three HDV genotypes. Most published HDV sequences, including those from North America, Europe, the Middle East, the South Pacific, and Asia, belong to a single genotype which may have some geographically based subtypes. A single Japanese isolate is the sole representative of a second HDV genotype. The South American sequences reported here constitute a third genotype. The association of a particular genotype with the severe form of type D hepatitis that occurs in northern South America supports the hypothesis that HDV genetic factors are important determinants in the pathogenesis of type D hepatitis.
Adolescent↗
A new species of arboreal pitviper from the Atlantic versant of northern Central America.
A new species of green, prehensile-tailed pitviper of the genus Bothriechis is described from the Atlantic slopes of eastern Guatemala and western Honduras. This species appears to be most closely related to B. bicolor of the Pacific versant of Chiapas (Mexico) and Guatemala. Several other species of Bothriechis occur on the Atlantic versant of northern Central America, including two montane species, B. aurifer and B. marchi but, with one possible exception, these are not known to be sympatric with the new species and occur in different mountain ranges. The widespread B. schlegelii occurs up to at least 900 m on the Sierra de Caral, where the lowest elevation recorded for the new species is 885 m.
Animals↗
Aspects of Northern Irish migration to America: definitions and directions.
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Americas↗
Comparison of stomach cancer incidence and survival in four continents.
The aim of this study was to compare stomach cancer incidence and survival rates between four very distinct areas: Campinas (Brasil), Latin America, Iowa (USA), Northern America, Varese (Italy), Europe and Osaka (Japan) in Asia, and determine which of the differences are due to variations in the case mix and which are due to the care received. A proportional hazards regression method was applied to the relative survival rates to obtain geographical differences that were adjusted for age, gender, period of diagnosis, sub-site and stage. Age, gender, period and stage explained most of the variability between the areas (50-100% excess risk of death with respect to Osaka) in the survival rates for stomach cancer patients. In Iowa and Varese, information on the sub-site fully explained the remaining variability. The large survival differences between the four areas were almost totally due to the different case mixes of the stomach cancer patients. The importance of stage indicates that diagnostic delay may be a major clinical factor affecting survival.
Adolescent↗
[The world is free of pox - Implementation and success of a grandiose program].
At the beginning of this century the compulsory vaccination and revaccination which was legally founded after the introduction of the vaccination by Jenner (1796) led to the removal of the smallpox in Europe and Northern America. However, up to the sixties in the developing countries of Asia, Africa as well as of Southern America and Middle America still fell ill and died of small-pox millions of people. Between 1953 and 1973 importations into countries of Europe and Northern America took place in 51 cases. In 1959 on the motion of the USSR the WHO decided performance of a world-wide eradication programme of small-pox which could be led to success with comprehensive personal, material and financial support of many countries. Flanking scientific, technological and methodical measures were of essential importance. In May 1980 the World Health Assembly in Geneva announced in solemn form the world-wide eradication of the small-pox and gave recommendations to the member countries for concluding measures concerning the small-pox vaccination, the foundation of vaccine reserves and the control of the epidemiological situation in the world. Also in the GDR the small-pox vaccination in childhood could be abolished.
Developing Countries↗
A revertant of the major founder Native American haplogroup C common in populations from northern South America.
We examined the mtDNA RFLP diversity of 17 Native American populations from Colombia. Five of the populations studied were found to have variable frequencies of a mtDNA type lacking the characteristic changes of haplogroups A-D. Sequencing of mtDNA HVS-I and II showed that this "null" RFLP type carries all the substitutions characteristic of Native American founder lineage C. A back mutation has therefore recreated the +13,259 HincII/-13,262 AluI restriction sites that tipify RFLP haplogroup C. This revertant C lineage is further characterized by three changes in HVS-II sequence: C/T transitions at positions 115 and 152, and the deletion of an A residue at position 116. This lineage is observed at high frequency mostly in populations from Greenberg's Equatorial-Tucano linguistic family. Genetic structure analyses are consistent with the reversion mutation occurring at an early stage during the tribalization process.
Colombia↗
Specific histologic features of Santa Marta hepatitis: a severe form of hepatitis delta-virus infection in northern South America.
Stimulated by observations in an outbreak of hepatitis delta-virus infection among Yucpa Indians in Venezuela, in which unusual histologic features were found, we studied 100 cases of fatal hepatitis from Colombia, South America, which had been obtained by autopsy or viscerotomy. These cases were considered to be "Santa Marta hepatitis," or "hepatitis of the Sierra Nevada de Santa Marta," which has been observed in this region for more than 40 years. Of the 100 cases, 19 had a variety of histologic lesions or were normal, and hepatitis delta-virus antigen was not demonstrated immunocytochemically in any of them. By contrast, 81 cases had a characteristic histologic picture with intense microvesicular steatosis associated with conspicuous eosinophilic necrosis of the hepatocytes, which apparently were sluggishly removed by cytolysis. Hepatitis delta-virus antigen was detected in 70% of the 81 cases, and the absence of detection of this antigen was often associated with poor tissue preservation and more extensive hepatocyte necrosis. A smaller percentage of patients had hepatitis B virus antigens detectable in liver tissue. The characteristic lesion in these 81 cases could be distinguished from other causes of microvesicular steatosis by the extensive eosinophilic necrosis. Other variable accompanying features included intraacinar, mainly macrophagic, scavenger cell inflammation, intense portal inflammation, a parenchymal regeneration, and ductular and arteriolar proliferation. Santa Marta hepatitis as a severe form of hepatitis delta-virus infection differs markedly from fulminant delta-hepatitis in Europe and the United States in which the microsteatosis with marked eosinophilic degeneration is not found. The causes for these differences are unknown but may relate to nutritional factors or environmental toxins.(ABSTRACT TRUNCATED AT 250 WORDS)
Antigens, Viral↗