RESUMO
Brucellosis, a zoonotic disease, was made statutorily notifiable in China in 1955. We analyzed the incidence and spatial-temporal distribution of human brucellosis during 1955-2014 in China using notifiable surveillance data: aggregated data for 1955-2003 and individual case data for 2004-2014. A total of 513,034 brucellosis cases were recorded, of which 99.3% were reported in northern China during 1955-2014, and 69.1% (258, 462/374, 141) occurred during February-July in 1990-2014. Incidence remained high during 1955-1978 (interquartile range 0.42-1.0 cases/100,000 residents), then decreased dramatically in 1979-1994. However, brucellosis has reemerged since 1995 (interquartile range 0.11-0.23 in 1995-2003 and 1.48-2.89 in 2004-2014); the historical high occurred in 2014, and the affected area expanded from northern pastureland provinces to the adjacent grassland and agricultural areas, then to southern coastal and southwestern areas. Control strategies in China should be adjusted to account for these changes by adopting a One Health approach.
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Brucelose/epidemiologia , Adolescente , Adulto , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Animais , Brucelose/história , Brucelose/microbiologia , Brucelose/transmissão , Criança , Pré-Escolar , China/epidemiologia , Notificação de Doenças , Reservatórios de Doenças , Feminino , Mapeamento Geográfico , História do Século XX , História do Século XXI , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Vigilância da População , Estações do Ano , Análise Espaço-Temporal , Adulto Jovem , Zoonoses/epidemiologiaRESUMO
OBJECTIVE: To ascertain the trends and burden of malaria in China and the costs of interventions for 2011-2015. METHODS: We analysed the spatiotemporal and demographic features of locally transmitted and imported malaria cases using disaggregated surveillance data on malaria from 2011 to 2015, covering the range of dominant malaria vectors in China. The total and mean costs for malaria elimination were calculated by funding sources, interventions and population at risk. FINDINGS: A total of 17 745 malaria cases, including 123 deaths (0.7%), were reported in mainland China, with 15 840 (89%) being imported cases, mainly from Africa and south-east Asia. Almost all counties of China (2855/2858) had achieved their elimination goals by 2015, and locally transmitted cases dropped from 1469 cases in 2011 to 43 cases in 2015, mainly occurring in the regions bordering Myanmar where Anopheles minimus and An. dirus are the dominant vector species. A total of United States dollars (US$) 134.6 million was spent in efforts to eliminate malaria during 2011-2015, with US$ 57.2 million (43%) from the Global Fund to Fight AIDS, Tuberculosis and Malaria and US$ 77.3 million (57%) from the Chinese central government. The mean annual investment (US$ 27 million) per person at risk (574 million) was US$ 0.05 (standard deviation: 0.03). CONCLUSION: The locally transmitted malaria burden in China has decreased. The key challenge is to address the remaining local transmission, as well as to reduce imported cases from Africa and south-east Asia. Continued efforts and appropriate levels of investment are needed in the 2016-2020 period to achieve elimination.
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Controle de Doenças Transmissíveis/organização & administração , Malária/epidemiologia , Malária/prevenção & controle , Animais , Anopheles , Antimaláricos/uso terapêutico , China/epidemiologia , Controle de Doenças Transmissíveis/economia , Humanos , Insetos Vetores , Mosquiteiros Tratados com Inseticida/economia , Inseticidas/administração & dosagem , Inseticidas/economia , Malária/tratamento farmacológico , Plasmodium/classificação , Análise Espaço-TemporalRESUMO
INTRODUCTION: The precise trigger of podoconiosis - endemic non-filarial elephantiasis of the lower legs - is unknown. Epidemiological and ecological studies have linked the disease with barefoot exposure to red clay soils of volcanic origin. Histopathology investigations have demonstrated that silicon, aluminium, magnesium and iron are present in the lower limb lymph node macrophages of both patients and non-patients living barefoot on these clays. We studied the spatial variation (variations across an area) in podoconiosis prevalence and the associated environmental factors with a goal to better understanding the pathogenesis of podoconiosis. METHODS: Fieldwork was conducted from June 2011 to February 2013 in 12 kebeles (administrative units) in northern Ethiopia. Geo-located prevalence data and soil samples were collected and analysed along with secondary geological, topographic, meteorological and elevation data. Soil data were analysed for chemical composition, mineralogy and particle size, and were interpolated to provide spatially continuous information. Exploratory, spatial, univariate and multivariate regression analyses of podoconiosis prevalence were conducted in relation to primary (soil) and secondary (elevation, precipitation, and geology) covariates. RESULTS: Podoconiosis distribution showed spatial correlation with variation in elevation and precipitation. Exploratory analysis identified that phyllosilicate minerals, particularly clay (smectite and kaolinite) and mica groups, quartz (crystalline silica), iron oxide, and zirconium were associated with podoconiosis prevalence. The final multivariate model showed that the quantities of smectite (RR = 2.76, 95% CI: 1.35, 5.73; p = 0.007), quartz (RR = 1.16, 95% CI: 1.06, 1.26; p = 0.001) and mica (RR = 1.09, 95% CI: 1.05, 1.13; p < 0.001) in the soil had positive associations with podoconiosis prevalence. CONCLUSIONS: More quantities of smectite, mica and quartz within the soil were associated with podoconiosis prevalence. Together with previous work indicating that these minerals may influence water absorption, potentiate infection and be toxic to human cells, the present findings suggest that these particles may play a role in the pathogenesis of podoconiosis and acute adenolymphangitis, a common cause of morbidity in podoconiosis patients.
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Elefantíase/epidemiologia , Monitoramento Ambiental/métodos , Mapeamento Geográfico , Poluentes do Solo/análise , Elefantíase/diagnóstico , Etiópia/epidemiologia , Humanos , Fatores de RiscoRESUMO
BACKGROUND: Transmission of Plasmodium vivax malaria is dependent on vector availability, biting rates and parasite development. In turn, each of these is influenced by climatic conditions. Correlations have previously been detected between seasonal rainfall, temperature and malaria incidence patterns in various settings. An understanding of seasonal patterns of malaria, and their weather drivers, can provide vital information for control and elimination activities. This research aimed to describe temporal patterns in malaria, rainfall and temperature, and to examine the relationships between these variables within four counties of Yunnan Province, China. METHODS: Plasmodium vivax malaria surveillance data (1991-2006), and average monthly temperature and rainfall were acquired. Seasonal trend decomposition was used to examine secular trends and seasonal patterns in malaria. Distributed lag non-linear models were used to estimate the weather drivers of malaria seasonality, including the lag periods between weather conditions and malaria incidence. RESULTS: There was a declining trend in malaria incidence in all four counties. Increasing temperature resulted in increased malaria risk in all four areas and increasing rainfall resulted in increased malaria risk in one area and decreased malaria risk in one area. The lag times for these associations varied between areas. CONCLUSIONS: The differences detected between the four counties highlight the need for local understanding of seasonal patterns of malaria and its climatic drivers.
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Malária Vivax/epidemiologia , China/epidemiologia , Humanos , Incidência , Distribuição de Poisson , Chuva , Estações do Ano , TemperaturaRESUMO
BACKGROUND: Specific land cover types and activities have been correlated with Trypanosoma brucei rhodesiense distributions, indicating the importance of landscape for epidemiological risk. However, methods proposed to identify specific areas with elevated epidemiological risk (i.e. where transmission is more likely to occur) tend to be costly and time consuming. This paper proposes an exploratory spatial analysis using geo-referenced human African trypanosomiasis (HAT) cases and matched controls from Serere hospital, Uganda (December 1998 to November 2002) to identify areas with an elevated epidemiological risk of HAT. METHODS: Buffers 3 km from each case and control were used to represent areas in which village inhabitants would carry out their daily activities. It was hypothesised that the selection of areas where several case village buffers overlapped would enable the identification of locations with increased risk of HAT transmission, as these areas were more likely to be frequented by HAT cases in several surrounding villages. The landscape within these overlap areas should more closely relate to the environment in which transmission occurs as opposed to using the full buffer areas. The analysis was carried out for each of four annual periods, for both cases and controls, using a series of threshold values (number of overlapping buffers), including a threshold of one, which represented the benchmark (e.g. use of the full buffer area as opposed to the overlap areas). RESULTS: A greater proportion of the overlap areas for cases consisted of seasonally flooding grassland and lake fringe swamp, than the control overlap areas, correlating well with the preferred habitat of the predominant tsetse species within the study area (Glossina fuscipes fuscipes). The use of overlap areas also resulted in a greater difference between case and control landscapes, when compared with the benchmark (using the full buffer area). CONCLUSIONS: These results indicate that the overlap analysis has enabled the selection of areas more likely to represent epidemiological risk zones than similar analyses using full buffer areas. The identification of potential epidemiological risk zones using this method requires fewer data than other proposed methods and further development may provide vital information for the targeting of control measures.
Assuntos
Sistemas de Informação Geográfica , Topografia Médica , Trypanosoma brucei rhodesiense/isolamento & purificação , Tripanossomíase Africana/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Medição de Risco , Uganda/epidemiologia , Adulto JovemRESUMO
Water point mapping databases, generated through surveys of water sources such as wells and boreholes, are now available in many low and middle income countries, but often suffer from incomplete coverage. To address the partial coverage in such databases and gain insights into spatial patterns of water resource use, this study investigated the use of a maximum entropy (MaxEnt) approach to predict the geospatial distribution of drinking-water sources, using two types of unimproved sources in Kenya as illustration. Geographic locations of unprotected dug wells and surface water sources derived from the Water Point Data Exchange (WPDx) database were used as inputs to the MaxEnt model alongside geological/hydrogeological and socio-economic covariates. Predictive performance of the MaxEnt models was high (all > 0.9) based on Area Under the Receiver Operator Curve (AUC), and the predicted spatial distribution of water point was broadly consistent with household use of these unimproved drinking-water sources reported in household survey and census data. In developing countries where geospatial datasets concerning drinking-water sources often have necessarily limited resolution or incomplete spatial coverage, the modelled surface can provide an initial indication of the geography of unimproved drinking-water sources to target unserved populations and assess water source vulnerability to contamination and hazards.
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Censos , Bases de Dados Factuais , Água Potável , Poços de Água , Humanos , QuêniaRESUMO
BACKGROUND: Current priorities for diarrhoeal disease prevention include use of sanitation and safe water. There have been few attempts to quantify the importance of animal faeces in drinking-water contamination, despite the presence of potentially water-borne zoonotic pathogens in animal faeces. OBJECTIVES: This study aimed to quantify the relationship between livestock ownership and point-of-consumption drinking-water contamination. METHODS: Data from nationally representative household surveys in Nepal, Bangladesh, and Ghana, each with associated water quality assessments, were used. Multinomial regression adjusting for confounders was applied to assess the relationship between livestock ownership and the level of drinking-water contamination with E. coli. RESULTS: Ownership of five or more large livestock (e.g. cattle) was significantly associated with drinking-water contamination in Ghana (RRR=7.9, 95% CI=1.6 to 38.9 for medium levels of contamination with 1-31cfu/100ml; RRR=5.2, 95% CI=1.1-24.5 for high levels of contamination with >31cfu/100ml) and Bangladesh (RRR=2.4, 95% CI=1.3-4.5 for medium levels of contamination; non-significant for high levels of contamination). Ownership of eight or more poultry (chickens, guinea fowl, ducks or turkeys) was associated with drinking-water contamination in Bangladesh (RRR=1.5, 95% CI=1.1-2.0 for medium levels of contamination, non-significant for high levels of contamination). CONCLUSIONS: These results suggest that livestock ownership is a significant risk factor for the contamination of drinking-water at the point of consumption. This indicates that addressing human sanitation without consideration of faecal contamination from livestock sources will not be sufficient to prevent drinking-water contamination.
Assuntos
Criação de Animais Domésticos/estatística & dados numéricos , Água Potável/microbiologia , Animais , Bangladesh , Características da Família/etnologia , Gana , Nepal , Inquéritos e Questionários , Microbiologia da ÁguaRESUMO
Due to worldwide increased human mobility, air-transportation data and mathematical models have been widely used to measure risks of global dispersal of pathogens. However, the seasonal and interannual risks of pathogens importation and onward transmission from endemic countries have rarely been quantified and validated. We constructed a modelling framework, integrating air travel, epidemiological, demographical, entomological and meteorological data, to measure the seasonal probability of dengue introduction from endemic countries. This framework has been applied retrospectively to elucidate spatiotemporal patterns and increasing seasonal risk of dengue importation from South-East Asia into China via air travel in multiple populations, Chinese travelers and local residents, over a decade of 2005-15. We found that the volume of airline travelers from South-East Asia into China has quadrupled from 2005 to 2015 with Chinese travelers increased rapidly. Following the growth of air traffic, the probability of dengue importation from South-East Asia into China has increased dramatically from 2005 to 2015. This study also revealed seasonal asymmetries of transmission routes: Sri Lanka and Maldives have emerged as origins; neglected cities at central and coastal China have been increasingly vulnerable to dengue importation and onward transmission. Compared to the monthly occurrence of dengue reported in China, our model performed robustly for importation and onward transmission risk estimates. The approach and evidence could facilitate to understand and mitigate the changing seasonal threat of arbovirus from endemic regions.
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Dengue/epidemiologia , Dengue/transmissão , Aedes/fisiologia , Aedes/virologia , Animais , Sudeste Asiático , China/epidemiologia , Dengue/virologia , Vírus da Dengue/fisiologia , Humanos , Mosquitos Vetores/fisiologia , Mosquitos Vetores/virologia , Estudos Retrospectivos , Estações do Ano , ViagemRESUMO
Sustainable Development Goal (SDG) 6 has expanded the Millennium Development Goals' focus from improved drinking-water to safely managed water services. This expanded focus to include issues such as water quality requires richer monitoring data and potentially integration of datasets from different sources. Relevant data sets include water point mapping (WPM), the survey of boreholes, wells and other water points, census and household survey data. This study examined inconsistencies between population census and WPM datasets for Cambodia, Liberia and Tanzania, and identified potential barriers to integrating the two datasets to meet monitoring needs. Literatures on numbers of people served per water point were used to convert WPM data to population served by water source type per area and compared with census reports. For Cambodia and Tanzania, discrepancies with census data suggested incomplete WPM coverage. In Liberia, where the data sets were consistent, WPM-derived data on functionality, quantity and quality of drinking water were further combined with census area statistics to generate an enhanced drinking-water access measure for protected wells and springs. The process revealed barriers to integrating census and WPM data, including exclusion of water points not used for drinking by households, matching of census and WPM source types; temporal mismatches between data sources; data quality issues such as missing or implausible data values, and underlying assumptions about population served by different water point technologies. However, integration of these two data sets could be used to identify and rectify gaps in WPM coverage. If WPM databases become more complete and the above barriers are addressed, it could also be used to develop more realistic measures of household drinking-water access for monitoring.
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Censos , Abastecimento de Água , Camboja , Humanos , Libéria , TanzâniaRESUMO
The pork tapeworm, Taenia solium, causes an important economic and health burden, mainly in rural or marginalized communities of sub-Saharan Africa, Asia, and Latin-America. Although improved pig rearing conditions seem to have eliminated the parasite in most Western European countries, little is known about the true endemicity status of T. solium throughout Europe. Three recent reviews indicate that autochthonous human T. solium taeniasis/cysticercosis may be possible in Europe, but that current peer-reviewed literature is biased towards Western Europe. Officially reported data on porcine cysticercosis are highly insufficient. Favourable conditions for local T. solium transmission still exist in eastern parts of Europe, although the ongoing integration of the European Union is speeding up modernisation and intensification of the pig sector. Further evidence is urgently needed to fill the gaps on the European T. solium endemicity map. We urge to make human cysticercosis notifiable and to improve the reporting of porcine cysticercosis.
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Doenças Transmissíveis Emergentes/veterinária , Carne Vermelha/parasitologia , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/parasitologia , Suínos/parasitologia , Taenia solium/isolamento & purificação , Teníase/veterinária , Criação de Animais Domésticos , Animais , Anticestoides/uso terapêutico , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/prevenção & controle , Doenças Transmissíveis Emergentes/transmissão , Europa (Continente)/epidemiologia , Humanos , Prevalência , Saúde Pública , Fatores de Risco , Saúde da População Rural , População Rural , Doenças dos Suínos/transmissão , Teníase/epidemiologia , Teníase/parasitologia , Teníase/transmissão , ZoonosesRESUMO
The development and application of interventions for the control of vector-borne zoonoses requires broad understanding of epidemiological linkages between vector, animal infection and human infection. However, there are significant gaps in our understanding of these linkages and a lack of appropriate data poses a considerable barrier to addressing this issue. A move towards strengthened surveillance of vectors and disease in both animal and human hosts, in combination with linked human-animal surveys, could form the backbone for epidemiological integration, enabling explicit assessment of the animal-human (and vector) interface, and subsequent implications for spill-over to human populations. Currently available data on the spatial distribution of human African trypanosomiasis allow an illustrative example.
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Tripanossomíase Africana/epidemiologia , Moscas Tsé-Tsé/parasitologia , Zoonoses/epidemiologia , Animais , Prioridades em Saúde , Humanos , Insetos Vetores , Vigilância de Evento Sentinela , Tripanossomíase Africana/prevenção & controleRESUMO
There remain few nationally representative studies of drinking water quality at the point of consumption in developing countries. This study aimed to examine factors associated with E. coli contamination in Ghana. It drew on a nationally representative household survey, the 2012-2013 Living Standards Survey 6, which incorporated a novel water quality module. E. coli contamination in 3096 point-of-consumption samples was examined using multinomial regression. Surface water use was the strongest risk factor for high E. coli contamination (relative risk ratio (RRR) = 32.3, p < 0.001), whilst packaged (sachet or bottled) water use had the greatest protective effect (RRR = 0.06, p < 0.001), compared to water piped to premises. E. coli contamination followed plausible patterns with digit preference (tendency to report values ending in zero) in bacteria counts. The analysis suggests packaged drinking water use provides some protection against point-of-consumption E. coli contamination and may therefore benefit public health. It also suggests viable water quality data can be collected alongside household surveys, but field protocols require further revision.
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Água Potável/microbiologia , Exposição Ambiental/estatística & dados numéricos , Escherichia coli/isolamento & purificação , Microbiologia da Água , Poluição da Água/estatística & dados numéricos , Qualidade da Água , Estudos Transversais , Exposição Ambiental/análise , Gana , Humanos , Fatores de Risco , Inquéritos e Questionários , Poluição da Água/análiseRESUMO
Following the recent expiry of the United Nations' 2015 Millennium Development Goals (MDGs), new international development agenda covering 2030 water, sanitation and hygiene (WASH) targets have been proposed, which imply new demands on data sources for monitoring relevant progress. This study evaluates drinking-water and sanitation classification systems from national census questionnaire content, based upon the most recent international policy changes, to examine national population census's ability to capture drinking-water and sanitation availability, safety, accessibility, and sustainability. In total, 247 censuses from 83 low income and lower-middle income countries were assessed using a scoring system, intended to assess harmonised water supply and sanitation classification systems for each census relative to the typology needed to monitor the proposed post-2015 indicators of WASH targets. The results signal a lack of international harmonisation and standardisation in census categorisation systems, especially concerning safety, accessibility, and sustainability of services in current census content. This suggests further refinements and harmonisation of future census content may be necessary to reflect ambitions for post-2015 monitoring.
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Água Potável/normas , Saneamento/classificação , Censos , Países em Desenvolvimento/estatística & dados numéricos , Saúde Global/classificação , Saúde Global/normas , Programas Gente Saudável/normas , Humanos , Saneamento/normas , Inquéritos e Questionários , Banheiros/normas , Banheiros/estatística & dados numéricosRESUMO
Use of drinking water sold in plastic bags (sachet water) is growing rapidly in west Africa. The impact on water consumption and child health remains unclear, and a debate on the taxation and regulation of sachet water is ongoing. This study assessed the feasibility of providing subsidized sachet water to low-income urban households in Accra and measured the resultant changes in water consumption. A total of 86 children, 6-36 months of age in neighborhoods lacking indoor piped water, were randomized to three study arms. The control group received education about diarrhea. The second arm received vouchers for 15 L/week/child of free water sachets (value: $0.63/week) plus education. The third arm received vouchers for the same water sachet volume at half price plus education. Water consumption was measured at baseline and followed for 4 months thereafter. At baseline, 66 of 81 children (82%) drank only sachet water. When given one voucher/child/week, households redeemed an average 0.94 vouchers/week/child in the free-sachet-voucher arm and 0.82 vouchers/week/child in the half-price arm. No change in water consumption was observed in the half-price arm, although the study was not powered to detect such differences. In the free-sachet-voucher arm, estimated sachet water consumption increased by 0.27 L/child/day (P = 0.03). The increase in sachet water consumption by children in the free-sachet-voucher arm shows that provision of fully subsidized water sachets might improve the quality of drinking water consumed by children. Further research is needed to quantify this and any related child health impacts.
Assuntos
Diarreia/economia , Diarreia/prevenção & controle , Água Potável/normas , Financiamento Governamental/economia , Abastecimento de Água/economia , Pré-Escolar , Estudos Transversais , Estudos de Viabilidade , Feminino , Gana , Humanos , Lactente , Masculino , Microbiologia da Água/normasRESUMO
Evidence suggests that the intracellular bacterial pathogen Coxiella burnetii (which causes Q fever) is widespread, with a near global distribution. While there has been increasing attention to Q fever epidemiology in high-income settings, a recent systematic review highlighted significant gaps in our understanding of the prevalence, spatial distribution and risk factors for Q fever infection across Africa. This research aimed to provide a One Health assessment of Q fever epidemiology in parts of Western and Nyanza Provinces, Western Kenya, in cattle and humans. A cross-sectional survey was conducted: serum samples from 2049 humans and 955 cattle in 416 homesteads were analysed for C. burnetii antibodies. Questionnaires covering demographic, socio-economic and husbandry information were also administered. These data were linked to environmental datasets based on geographical locations (e.g., land cover). Correlation and spatial-cross correlation analyses were applied to assess the potential link between cattle and human seroprevalence. Multilevel regression analysis was used to assess the relationships between a range of socio-economic, demographic and environmental factors and sero-positivity in both humans and animals. The overall sero-prevalence of C. burnetii was 2.5% in humans and 10.5% in cattle, but we found no evidence of correlation between cattle and human seroprevalence either within households, or when incorporating spatial proximity to other households in the survey. Multilevel modelling indicated the importance of several factors for exposure to the organism. Cattle obtained from market (as opposed to those bred in their homestead) and those residing in areas with lower precipitation levels had the highest sero-prevalence. For humans, the youngest age group had the highest odds of seropositivity, variations were observed between ethnic groups, and frequent livestock contact (specifically grazing and dealing with abortion material) was also a risk factor. These results illustrate endemicity of C. burnetii in western Kenya, although prevalence is relatively low. The analysis indicates that while environmental factors may play a role in cattle exposure patterns, human exposure patterns are likely to be driven more strongly by livestock contacts. The implication of livestock markets in cattle exposure risks suggests these may be a suitable target for interventions.
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Anticorpos Antibacterianos/sangue , Doenças dos Bovinos/sangue , Coxiella burnetii/isolamento & purificação , Febre Q/sangue , Adolescente , Adulto , Animais , Bovinos , Doenças dos Bovinos/enzimologia , Doenças dos Bovinos/imunologia , Doenças dos Bovinos/microbiologia , Criança , Pré-Escolar , Coxiella burnetii/genética , Coxiella burnetii/imunologia , Estudos Transversais , Feminino , Humanos , Lactente , Quênia/epidemiologia , Gado , Masculino , Pessoa de Meia-Idade , Prevalência , Febre Q/epidemiologia , Febre Q/imunologia , Febre Q/microbiologia , Estudos Soroepidemiológicos , Adulto Jovem , Zoonoses/sangue , Zoonoses/epidemiologia , Zoonoses/imunologia , Zoonoses/microbiologiaRESUMO
Plasmodium falciparum malaria importation from Africa to China is rising with increasing Chinese overseas investment and international travel. Identifying networks and drivers of this phenomenon as well as the contributors to high case-fatality rate is a growing public health concern to enable efficient response. From 2011-2015, 8653 P. falciparum cases leading to 98 deaths (11.3 per 1000 cases) were imported from 41 sub-Saharan countries into China, with most cases (91.3%) occurring in labour-related Chinese travellers. Four strongly connected groupings of origin African countries with destination Chinese provinces were identified, and the number of imported cases was significantly associated with the volume of air passengers to China (P = 0.006), parasite prevalence in Africa (P < 0.001), and the amount of official development assistance from China (P < 0.001) with investment in resource extraction having the strongest relationship with parasite importation. Risk factors for deaths from imported cases were related to the capacity of malaria diagnosis and diverse socioeconomic factors. The spatial heterogeneity uncovered, principal drivers explored, and risk factors for mortality found in the rising rates of P. falciparum malaria importation to China can serve to refine malaria elimination strategies and the management of cases, and high risk groups and regions should be targeted.
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Malária Falciparum/epidemiologia , Malária Falciparum/mortalidade , Malária Falciparum/transmissão , Plasmodium falciparum , Adulto , África/epidemiologia , China/epidemiologia , Bases de Dados Factuais , Feminino , Geografia , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Saúde Pública , Fatores de Risco , ViagemRESUMO
[This corrects the article DOI: 10.1371/journal.pntd.0004223.].
RESUMO
Avian influenza A H5N1 viruses have caused many, typically severe, human infections since the first human case was reported in 1997. However, no comprehensive epidemiological analysis of global human cases of H5N1 from 1997 to 2015 exists. Moreover, few studies have examined in detail the changing epidemiology of human H5N1 cases in Egypt, especially given the outbreaks since November, 2014, which have the highest number of cases ever reported worldwide in a similar period. Data on individual patients were collated from different sources using a systematic approach to describe the global epidemiology of 907 human H5N1 cases between May, 1997, and April, 2015. The number of affected countries rose between 2003 and 2008, with expansion from east and southeast Asia, then to west Asia and Africa. Most cases (67·2%) occurred from December to March, and the overall case-fatality risk was 483 (53·5%) of 903 cases which varied across geographical regions. Although the incidence in Egypt has increased dramatically since November, 2014, compared with the cases beforehand, there were no significant differences in the fatality risk, history of exposure to poultry, history of patient contact, and time from onset to hospital admission in the recent cases.
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Influenza Aviária/epidemiologia , Influenza Humana/epidemiologia , Animais , Surtos de Doenças , Saúde Global , Humanos , Incidência , Virus da Influenza A Subtipo H5N1/patogenicidade , Influenza Aviária/transmissão , Aves Domésticas/virologiaRESUMO
Tsetse flies transmit trypanosomes, the causative agent of human and animal African trypanosomiasis. The tsetse vector is extensively distributed across sub-Saharan Africa. Trypanosomiasis maintenance is determined by the interrelationship of three elements: vertebrate host, parasite and the vector responsible for transmission. Mapping the distribution and abundance of tsetse flies assists in predicting trypanosomiasis distributions and developing rational strategies for disease and vector control. Given scarce resources to carry out regular full scale field tsetse surveys to up-date existing tsetse maps, there is a need to devise inexpensive means for regularly obtaining dependable area-wide tsetse data to guide control activities. In this study we used spatial epidemiological modelling techniques (logistic regression) involving 5000 field-based tsetse-data (G. f. fuscipes) points over an area of 40,000 km2, with satellite-derived environmental surrogates composed of precipitation, temperature, land cover, normalised difference vegetation index (NDVI) and elevation at the sub-national level. We used these extensive tsetse data to analyse the relationships between presence of tsetse (G. f. fuscipes) and environmental variables. The strength of the results was enhanced through the application of a spatial autologistic regression model (SARM). Using the SARM we showed that the probability of tsetse presence increased with proportion of forest cover and riverine vegetation. The key outputs are a predictive tsetse distribution map for the Lake Victoria basin of Uganda and an improved understanding of the association between tsetse presence and environmental variables. The predicted spatial distribution of tsetse in the Lake Victoria basin of Uganda will provide significant new information to assist with the spatial targeting of tsetse and trypanosomiasis control.
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Distribuição Animal/fisiologia , Moscas Tsé-Tsé/parasitologia , Animais , Ecossistema , Humanos , Lagos , Moscas Tsé-Tsé/fisiologia , UgandaRESUMO
BACKGROUND: Previous analyses have shown the individual correlations between poverty, health and satellite-derived vegetation indices such as the normalized difference vegetation index (NDVI). However, generally these analyses did not explore the statistical interconnections between poverty, health outcomes and NDVI. METHODS: In this research aspatial methods (principal component analysis) and spatial models (variography, factorial kriging and cokriging) were applied to investigate the correlations and spatial relationships between intensity of poverty, health (expressed as child mortality and undernutrition), and NDVI for a large area of West Africa. RESULTS: This research showed that the intensity of poverty (and hence child mortality and nutrition) varies inversely with NDVI. From the spatial point-of-view, similarities in the spatial variation of intensity of poverty and NDVI were found. CONCLUSIONS: These results highlight the utility of satellite-based metrics for poverty models including health and ecological components and, in general for large scale analysis, estimation and optimisation of multidimensional poverty metrics. However, it also stresses the need for further studies on the causes of the association between NDVI, health and poverty. Once these relationships are confirmed and better understood, the presence of this ecological component in poverty metrics has the potential to facilitate the analysis of the impacts of climate change on the rural populations afflicted by poverty and child mortality.