Malaria in travelers: a review of the GeoSentinel surveillance network.
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BACKGROUND: Malaria is a common and important infection in travelers. METHODS: We have examined data reported to the GeoSentinel surveillance network to highlight characteristics of malaria in travelers. RESULTS: A total of 1140 malaria cases were reported (60% of cases were due to Plasmodium falciparum, 24% were due to Plasmodium vivax). Male subjects constituted 69% of the study population. The median duration of travel was 34 days; however, 37% of subjects had a travel duration of < or =4 weeks. The majority of travellers did not have a pretravel encounter with a health care provider. Most cases occurred in travelers (39%) or immigrants/refugees (38%). The most common reasons for travel were to visit friends/relatives (35%) or for tourism (26%). Three-quarters of infections were acquired in sub-Saharan Africa. Severe and/or complicated malaria occurred in 33 cases, with 3 deaths. Compared with others in the GeoSentinel database, patients with malaria had traveled to sub-Saharan Africa more often, were more commonly visiting friends/relatives, had traveled for longer periods, presented sooner after return, were more likely to have a fever at presentation, and were less likely to have had a pretravel encounter. In contrast to immigrants and visitors of friends or relatives, a higher proportion (73%) of the missionary/volunteer group who developed malaria had a pretravel encounter with a health care provider. Travel to sub-Saharan Africa and Oceania was associated with the greatest relative risk of acquiring malaria. CONCLUSIONS: We have used a global database to identify patient and travel characteristics associated with malaria acquisition and characterized differences in patient type, destinations visited, travel duration, and malaria species acquired. (+info)
Origin of the amphibian chytrid fungus.
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The sudden appearance of chytridiomycosis, the cause of amphibian deaths and population declines in several continents, suggests that its etiologic agent, the amphibian chytrid Batrachochytrium dendrobatidis, was introduced into the affected regions. However, the origin of this virulent pathogen is unknown. A survey was conducted of 697 archived specimens of 3 species of Xenopus collected from 1879 to 1999 in southern Africa in which the histologic features of the interdigital webbing were analyzed. The earliest case of chytridiomycosis found was in a Xenopus laevis frog in 1938, and overall prevalence was 2.7%. The prevalence showed no significant differences between species, regions, season, or time period. Chytridiomycosis was a stable endemic infection in southern Africa for 23 years before any positive specimen was found outside Africa. We propose that Africa is the origin of the amphibian chytrid and that the international trade in X. laevis that began in the mid-1930s was the means of dissemination. (+info)
Global trends in breast cancer incidence and mortality 1973-1997.
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BACKGROUND: Worldwide, breast cancer is the most common cancer and is the leading cause of cancer death among women. METHODS: To describe global trends, we compared age-adjusted incidence and mortality rates over three decades (from 1973-77 to 1993-97) and across several continents. RESULTS: Both breast cancer incidence and mortality rates varied 4-fold by geographic location between countries with the highest and lowest rates. Recent (1993-1997) incidence rates ranged from 27/100,000 in Asian countries to 97/100,000 among US white women. Overall, North American and northern European countries had the highest incidence rates of breast cancer; intermediate levels were reported in Western Europe, Oceania, Scandinavia, and Israel; and Eastern Europe, South and Latin America, and Asia had the lowest levels. Breast cancer incidence rose 30-40% from the 1970s to the 1990s in most countries, with the most marked increases among women aged > or =50 years. Mortality from breast cancer paralleled incidence: it was highest in the countries with the highest incidence rates (between 17/100,000 and 27/100,000), lowest in Latin America and Asia (7-14/100,000), and rose most rapidly in countries with the lowest rates. CONCLUSIONS: Breast cancer incidence and mortality rates remain highest in developed countries compared with developing countries, as a result of differential use of screening mammograms and disparities in lifestyle and hereditary factors. Future studies assessing the combined contributions of both environmental and hereditary factors may provide explanations for worldwide differences in incidence and mortality rates. (+info)
Traces of archaic mitochondrial lineages persist in Austronesian-speaking Formosan populations.
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Genetic affinities between aboriginal Taiwanese and populations from Oceania and Southeast Asia have previously been explored through analyses of mitochondrial DNA (mtDNA), Y chromosomal DNA, and human leukocyte antigen loci. Recent genetic studies have supported the "slow boat" and "entangled bank" models according to which the Polynesian migration can be seen as an expansion from Melanesia without any major direct genetic thread leading back to its initiation from Taiwan. We assessed mtDNA variation in 640 individuals from nine tribes of the central mountain ranges and east coast regions of Taiwan. In contrast to the Han populations, the tribes showed a low frequency of haplogroups D4 and G, and an absence of haplogroups A, C, Z, M9, and M10. Also, more than 85% of the maternal lineages were nested within haplogroups B4, B5a, F1a, F3b, E, and M7. Although indicating a common origin of the populations of insular Southeast Asia and Oceania, most mtDNA lineages in Taiwanese aboriginal populations are grouped separately from those found in China and the Taiwan general (Han) population, suggesting a prevalence in the Taiwanese aboriginal gene pool of its initial late Pleistocene settlers. Interestingly, from complete mtDNA sequencing information, most B4a lineages were associated with three coding region substitutions, defining a new subclade, B4a1a, that endorses the origin of Polynesian migration from Taiwan. Coalescence times of B4a1a were 13.2 +/- 3.8 thousand years (or 9.3 +/- 2.5 thousand years in Papuans and Polynesians). Considering the lack of a common specific Y chromosomal element shared by the Taiwanese aboriginals and Polynesians, the mtDNA evidence provided here is also consistent with the suggestion that the proto-Oceanic societies would have been mainly matrilocal. (+info)
Clinical characteristics of imported malaria in Japan: analysis at a referral hospital.
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Imported malaria remains an important problem in Japan. We have reviewed the medical records of 170 cases of malaria in our hospital, which corresponds to 14.9% of the total cases in Japan. The predominant malarial species was Plasmodium falciparum (52.3%), and the most frequent area of acquisition was Africa (54.2%), followed by Asia (20.9%) and Oceania (19.6%). The most common reason for travel among Japanese patients was business. A significant proportion (22.2%) of vivax malaria cases experienced relapse despite standard primaquine therapy. Most primaquine failures were from Oceania. We also found that a substantial number of Japanese patients contracted malaria without chemoprophylaxis and consulted medical facilities with an unfavorably long delay from initial symptoms (median: 3.0 days). Direct education of travelers and travel companies, in addition to health care providers, is likely necessary to improve outcomes of imported malaria. (+info)
Research contribution of different world regions in the top 50 biomedical journals (1995-2002).
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We evaluated all articles published by different world regions in the top 50 biomedical journals in the database of the Journal Citation Reports-Institute for Scientific Information for the period between 1995 and 2002. The world was divided into 9 regions [United States of America (the U.S.), Western Europe, Japan, Canada, Asia, Oceania, Latin America, and the Caribbean, Eastern Europe, and Africa] based on a combination of geographic, economic and scientific criteria. The number of articles published by each region, the mean impact factor, and the product of the above two parameters were our main indicators. The above numbers were also adjusted for population size, gross national income per capita of each region, and other factors. Articles published from the U.S. made up about two-thirds of all scientific papers published in the top 50 biomedical journals between 1995 and 2002. Western Europe contributed approximately a quarter of the published papers while the remaining one-tenth of articles came from the rest of the world. Canada, however, ranked second when number of articles was adjusted for population size. The U.S. is by far the highest-ranking country/region in publications in the top 50 biomedical journals even after adjusting for population size, gross national product, and other factors. Canada and Western Europe share the second place while the rest of the world is far behind. (+info)
Web-based surveillance and global Salmonella distribution, 2000-2002.
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Salmonellae are a common cause of foodborne disease worldwide. The World Health Organization (WHO) supports international foodborne disease surveillance through WHO Global Salm-Surv and other activities. WHO Global Salm-Surv members annually report the 15 most frequently isolated Salmonella serotypes to a Web-based country databank. We describe the global distribution of reported Salmonella serotypes from human and nonhuman sources from 2000 to 2002. Among human isolates, S. Enteritidis was the most common serotype, accounting for 65% of all isolates. Among nonhuman isolates, although no serotype predominated, Salmonella enterica serovar Typhimurium was reported most frequently. Several serotypes were reported from only 1 region of the world. The WHO Global Salm-Surv country databank is a valuable public health resource; it is a publicly accessible, Web-based tool that can be used by health professionals to explore hypotheses related to the sources and distribution of salmonellae worldwide. (+info)
Deciphering past human population movements in Oceania: provably optimal trees of 127 mtDNA genomes.
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The settlement of the many island groups of Remote Oceania occurred relatively late in prehistory, beginning approximately 3,000 years ago when people sailed eastwards into the Pacific from Near Oceania, where evidence of human settlement dates from as early as 40,000 years ago. Archeological and linguistic analyses have suggested the settlers of Remote Oceania had ancestry in Taiwan, as descendants of a proposed Neolithic expansion that began approximately 5,500 years ago. Other researchers have suggested that the settlers were descendants of peoples from Island Southeast Asia or the existing inhabitants of Near Oceania alone. To explore patterns of maternal descent in Oceania, we have assembled and analyzed a data set of 137 mitochondrial DNA (mtDNA) genomes from Oceania, Australia, Island Southeast Asia, and Taiwan that includes 19 sequences generated for this project. Using the MinMax Squeeze Approach (MMS), we report the consensus network of 165 most parsimonious trees for the Oceanic data set, increasing by many orders of magnitude the numbers of trees for which a provable minimal solution has been found. The new mtDNA sequences highlight the limitations of partial sequencing for assigning sequences to haplogroups and dating recent divergence events. The provably optimal trees found for the entire mtDNA sequences using the MMS method provide a reliable and robust framework for the interpretation of evolutionary relationships and confirm that the female settlers of Remote Oceania descended from both the existing inhabitants of Near Oceania and more recent migrants into the region. (+info)