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2.
Coron Artery Dis ; 31(8): 733-738, 2020 12.
Article in English | MEDLINE | ID: mdl-32404592

ABSTRACT

BACKGROUND: It remains unclear whether cardiovascular risk factors and access to healthcare for veterans with cardiovascular disease (CVD) vary among US regions. This study sought to determine the extent of regional variations in cardiovascular risk factors and access to medical care in a cohort of veterans with CVD in the USA. METHODS: The 2016 Centers for Disease Control Behavioral Risk Factor Surveillance Survey was utilized to identify a cohort of veteran patients with CVD. Participants were classified based on four US regions: (1) Northeast, (2) Midwest, (3) South, and (4) West. We compared demographic data, medical history, and access to care for veterans of each US region. The outcomes of interest included financial barriers to medical care and annual medical checkup. RESULTS: Among the 13 835 veterans, 18.3% were from the Northeast, while 23.5, 37.1, and 21.1% were from the Midwest, South, and West, respectively. Veterans of each region differed significantly with respect to demographic characteristics, prior medical history, and access to care. Rates of financial barriers to medical care were similar across the four regions (7.3 vs. 7.1 vs. 8.0 vs. 6.9%, P = 0.203). Veterans from the West had the lowest rates of medical checkup within the past year (91.7 vs. 89.5 vs. 91.4 vs. 86.6%). On multivariate analysis, the Midwest [odds ratio (OR) 0.69; 95% CI, 0.53-0.89] and West (OR 0.53; 95% CI 0.41-0.68) regions were independently associated with lower rates of medical checkup within the past year compared to the Northeast. CONCLUSIONS: In this observational study involving US veterans with CVD, cardiovascular risk factors and frequency of annual medical checkup differed amongst each US region. Further large-scale studies examining the prevalence of impaired access to care and quality of care in US veterans with CVD are warranted.


Subject(s)
Cardiovascular Diseases , Health Services Accessibility , Veterans Health Services , Cardiovascular Diseases/epidemiology , Cardiovascular Diseases/therapy , Demography , Female , Health Services Accessibility/standards , Health Services Accessibility/statistics & numerical data , Health Services Needs and Demand , Heart Disease Risk Factors , Humans , Male , Middle Aged , Prevalence , Quality Improvement/organization & administration , Topography, Medical/statistics & numerical data , United States/epidemiology , Veterans Health Services/standards , Veterans Health Services/statistics & numerical data
3.
Alcohol Clin Exp Res ; 43(8): 1714-1726, 2019 08.
Article in English | MEDLINE | ID: mdl-31157919

ABSTRACT

BACKGROUND: The objective of this analysis was to compare measurement methods-counts, proximity, mean distance, and spatial access-of calculating alcohol outlet density and violent crime using data from Baltimore, Maryland. METHODS: Violent crime data (n = 11,815) were obtained from the Baltimore City Police Department and included homicides, aggravated assaults, rapes, and robberies in 2016. We calculated alcohol outlet density and violent crime at the census block (CB) level (n = 13,016). We then weighted these CB-level measures to the census tract level (n = 197) and conducted a series of regressions. Negative binomial regression was used for count outcomes and linear regression for proximity and spatial access outcomes. Choropleth maps, partial R2 , Akaike's Information Criterion, and root mean squared error guided determination of which models yielded lower error and better fit. RESULTS: The inference depended on the measurement methods used. Eight models that used a count of alcohol outlets and/or violent crimes failed to detect an association between outlets and crime, and 3 other count-based models detected an association in the opposite direction. Proximity, mean distance, and spatial access methods consistently detected an association between outlets and crime and produced comparable model fits. CONCLUSIONS: Proximity, mean distance, and spatial access methods yielded the best model fits and had the lowest levels of error in this urban setting. Spatial access methods may offer conceptual strengths over proximity and mean distance. Conflicting findings in the field may be in part due to error in the way that researchers measure alcohol outlet density.


Subject(s)
Alcoholic Beverages/adverse effects , Commerce/statistics & numerical data , Crime/statistics & numerical data , Data Analysis , Topography, Medical/statistics & numerical data , Violence/statistics & numerical data , Baltimore , Humans , Models, Statistical , Regression Analysis , Topography, Medical/methods
4.
Spat Spatiotemporal Epidemiol ; 27: 37-45, 2018 11.
Article in English | MEDLINE | ID: mdl-30409375

ABSTRACT

When agencies release public-use data, they must be cognizant of the potential risk of disclosure associated with making their data publicly available. This issue is particularly pertinent in disease mapping, where small counts pose both inferential challenges and potential disclosure risks. While the small area estimation, disease mapping, and statistical disclosure limitation literatures are individually robust, there have been few intersections between them. Here, we formally propose the use of spatiotemporal data analysis methods to generate synthetic data for public use. Specifically, we analyze ten years of county-level heart disease death counts for multiple age-groups using a Bayesian model that accounts for dependence spatially, temporally, and between age-groups; generating synthetic data from the resulting posterior predictive distribution will preserve these dependencies. After demonstrating the synthetic data's privacy-preserving features, we illustrate their utility by comparing estimates of urban/rural disparities from the synthetic data to those from data with small counts suppressed.


Subject(s)
Confidentiality/standards , Spatio-Temporal Analysis , Topography, Medical , Bayes Theorem , Disclosure , Geographic Mapping , Humans , Models, Statistical , Risk , Topography, Medical/ethics , Topography, Medical/methods , Topography, Medical/statistics & numerical data
5.
Z Gastroenterol ; 53(6): 553-61, 2015 Jun.
Article in German | MEDLINE | ID: mdl-26075366

ABSTRACT

Obesity is a chronic disease whose origin is determined by genetic factors as well as environmental influences. The prevalence has rapidly increased worldwide in the recent decades. This paper evaluated the research on obesity in the period of 1900 - 2009 in the ISI "Web of Science" by Thomson Reuters. For this purpose scientometric methods were used and the results were graphically illustrated by "Density Equalizing Map Projections". From 1900 till 2009 94.987 published items are the basis for the present qualitative and quantitative data analysis. The publication rates show an exponential growth indicating a pronounced research activity. Concerning the country comparison the United States has the highest number of publications and citations, the highest modified h-index and most academic institutions. This manuscript shows the first comprehensive scientometric data on obesity. In this research area, the United States is a leader and is located at the center of global collaborations.


Subject(s)
Bibliometrics , Biomedical Research/statistics & numerical data , Biomedical Research/trends , Disease Outbreaks/statistics & numerical data , Obesity/epidemiology , Periodicals as Topic/statistics & numerical data , Global Health/statistics & numerical data , Global Health/trends , Humans , Prevalence , Risk Factors , Topography, Medical/statistics & numerical data , Topography, Medical/trends
6.
Health Aff (Millwood) ; 34(5): 836-43, 2015 May.
Article in English | MEDLINE | ID: mdl-25941286

ABSTRACT

Potentially avoidable hospitalizations are studied as an indirect measure of access to primary care. Understanding the determinants of these hospitalizations can help improve the quality, efficiency, and equity of health care delivery. Few studies have tackled the issue of potentially avoidable hospitalizations in France, and none has done so at the national level. We assessed disparities in potentially avoidable hospitalizations in France in 2012 and analyzed their determinants. The standardized rate of potentially avoidable hospitalizations ranged from 0.1 to 44.4 cases per 1,000 inhabitants, at the ZIP code level. Increased potentially avoidable hospitalizations were associated with higher mortality, lower density of acute care beds and ambulatory care nurses, lower median income, and lower education levels. This study unveils considerable variation in the rate of potentially avoidable hospitalizations in spite of France's mandatory, publicly funded health insurance system. In addition to epidemiological and sociodemographic factors, this study suggests that primary care organization plays a role in geographic disparities in potentially avoidable hospitalizations that might be addressed by increasing the number of nurses and enhancing team work in primary care. Policy makers should consider measuring potentially avoidable hospitalizations in France as an indicator of primary care organization.


Subject(s)
Health Services Misuse/statistics & numerical data , Hospitalization/statistics & numerical data , Topography, Medical/statistics & numerical data , France , Health Services Accessibility/statistics & numerical data , Mortality , Primary Health Care/statistics & numerical data , Socioeconomic Factors
8.
Demography ; 50(4): 1217-41, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23319207

ABSTRACT

The question of whether environmental conditions influence human migration has recently gained considerable attention, driven by claims that global environmental change will displace large populations. Despite this high level of interest, few quantitative studies have investigated the potential effects of environmental factors on migration, particularly in the developing world and for gradual but pervasive forms of environmental change. To address this, a retrospective migration survey was conducted in rural Ecuador and linked to data on topography, climate, and weather shocks. These data were used to estimate multivariate event history models of alternative forms of mobility (local mobility, internal migration, and international migration), controlling for a large number of covariates. This approach is generalizable to other study areas and responds to calls for the development of more rigorous methods in this field. The results indicate that adverse environmental conditions do not consistently increase rural out-migration and, in some cases, reduce migration. Instead, households respond to environmental factors in diverse ways, resulting in complex migratory responses. Overall, the results support an alternative narrative of environmentally induced migration that recognizes the adaptability of rural households in responding to environmental change.


Subject(s)
Emigration and Immigration/statistics & numerical data , Environment , Rural Population/statistics & numerical data , Adolescent , Adult , Climate , Data Collection/methods , Developing Countries/statistics & numerical data , Ecuador , Humans , Retrospective Studies , Socioeconomic Factors , Topography, Medical/statistics & numerical data , Weather , Young Adult
9.
J Neurol Sci ; 320(1-2): 79-84, 2012 Sep 15.
Article in English | MEDLINE | ID: mdl-22800767

ABSTRACT

BACKGROUND: Angiotensinogen (AGT) M235T and angiotensin-converting enzyme (ACE) Insertion/Deletion polymorphisms have been reported to be significantly associated with ischemic stroke. However, the results have been inconsistent. Therefore, we performed a comprehensive meta-analysis to evaluate the role of the AGT M235T and ACE I/D polymorphisms as risk factors for ischemic stroke in Han Chinese population. METHODS: We performed a comprehensive search in MEDLINE (PubMed), the China National Knowledge Infrastructure (CNKI) platforms and WANFANG databases, to identify the studies evaluating the association between the AGT M235T or ACE I/D polymorphisms and ischemic stroke, up to August 2011, in Chinese and English languages. The combined effects were estimated by fixed effects model or random effects model depending on the between-study heterogeneity, which was analyzed using the heterogeneity Q statistic test. Publication bias was evaluated using Begg's test, Egger's test and funnel plot. RESULTS: A total of 58 studies were selected for the final meta-analysis, including 7168 ischemic stroke cases and 5944 controls. Among them, 11 studies evaluated the effect of AGT M235T as a risk factor for ischemic stroke, while the remaining evaluated the ACE I/D polymorphism. Overall, a significant association was identified for both the AGT M235T and ACE I/D polymorphisms, under pair wise comparisons, dominant, recessive and additive models, however, there was significant heterogeneity among the ACE I/D polymorphism studies (P<0.10). On meta-regression analyses, geographic region was identified as a significant source of between-study heterogeneity for both the polymorphisms. The stratified analysis by geographic distribution indicated that the AGT T allele could increase the risk of ischemic stroke in northern Chinese (OR=2.029, 95% CI: 1.714-2.401, P<0.001) as compared to southern Chinese individuals (OR=1.821, 95% CI: 1.586-2.090, P=0.002). In contrast, the ACE D allele could increase the susceptibility of ischemic stroke in southern Chinese (OR=1.692, 95% CI: 1.455-1.966, P<0.001) as compared to northern Chinese individuals (OR=1.297, 95% CI: 1.089-1.545, P=0.004). There was a possibility of publication bias for ACE I/D (P<0.001), but not for AGT M235T (P>0.05). CONCLUSIONS: Our meta-analysis strongly suggested that the AGT M235T and ACE I/D polymorphisms significantly contribute to the risk of ischemic stroke in Han Chinese population. Also, the stratified analysis showed that the effects of these two polymorphisms differ by the geographic region. Further studies with more specific common information and large sample size are needed to understand the genetic mechanism of ischemic stroke.


Subject(s)
Angiotensinogen/genetics , Asian People/genetics , Peptidyl-Dipeptidase A/genetics , Stroke/epidemiology , Stroke/genetics , China/epidemiology , Genetic Predisposition to Disease/genetics , Humans , Polymorphism, Genetic/genetics , Publication Bias/statistics & numerical data , Regression Analysis , Risk Factors , Topography, Medical/statistics & numerical data
10.
PLoS Negl Trop Dis ; 6(4): e1620, 2012.
Article in English | MEDLINE | ID: mdl-22530073

ABSTRACT

BACKGROUND: The World Bank Loan Project (WBLP) for controlling schistosomiasis in China was implemented during 1992-2001. Its short-term impact has been assessed from non-spatial perspective, but its long-term impact remains unclear and a spatial evaluation has not previously been conducted. Here we compared the spatial distribution of schistosomiasis risk using national datasets in the lake and marshland regions from 1999-2001 and 2007-2008 to evaluate the long-term impact of WBLP strategy on China's schistosomiasis burden. METHODOLOGY/PRINCIPAL FINDINGS: A hierarchical Poisson regression model was developed in a Bayesian framework with spatially correlated and uncorrelated heterogeneities at the county-level, modeled using a conditional autoregressive prior structure and a spatially unstructured Gaussian distribution, respectively. There were two important findings from this study. The WBLP strategy was found to have a good short-term impact on schistosomiasis control, but its long-term impact was not ideal. It has successfully reduced the morbidity of schistosomiasis to a low level, but can not contribute further to China's schistosomiasis control because of the current low endemic level. A second finding is that the WBLP strategy could not effectively compress the spatial distribution of schistosomiasis risk. To achieve further reductions in schistosomiasis-affected areas, and for sustainable control, focusing on the intermediate host snail should become the next step to interrupt schistosomiasis transmission within the two most affected regions surrounding the Dongting and Poyang Lakes. Furthermore, in the lower reaches of the Yangtze River, the WBLP's morbidity control strategy may need to continue for some time until snails in the upriver provinces have been well controlled. CONCLUSION: It is difficult to further reduce morbidity due to schistosomiasis using a chemotherapy-based control strategy in the lake and marshland regions of China because of the current low endemic levels of infection. The future control strategy for schistosomiasis should instead focus on a snail-based integrated control strategy to maintain the program achievements and sustainably reduce the burden of schistosomiasis in China.


Subject(s)
Communicable Disease Control/methods , Schistosomiasis/epidemiology , Schistosomiasis/prevention & control , Topography, Medical/statistics & numerical data , Adolescent , Adult , Aged , Animals , Child , Child, Preschool , China/epidemiology , Communicable Disease Control/economics , Endemic Diseases , Female , Humans , Male , Middle Aged , Prevalence , Risk Assessment , Topography, Medical/economics , United Nations , Young Adult
11.
Transfusion ; 52(11): 2329-38, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22414141

ABSTRACT

BACKGROUND: Many studies on factors that can affect the frequency of blood donation have shown the influence of several individual characteristics. However, few studies have analyzed regional variations in blood donation frequency. The objective of this article is to verify to what extent individual and geographic variables influence blood donation in the Province of Québec, Canada. STUDY DESIGN AND METHODS: This article used a database provided by Héma-Québec (the organization in charge of blood collection in Québec), which included 426,247 donors, who made 1.4 million donations over a period of 5 years. Using the donors' residential postal codes and those of the blood collection sites, we created two geographic variables: the distance between the donor's place of residence and his or her collection site and each donor's region of residence. We subsequently modeled the frequency of blood donation and the different donor categories (based on the number of blood donations) using both a negative binomial regression model and an ordinal logistic regression model. RESULTS: The results indicate that, once the individual characteristics have been taken into account, the geographic variables, including proximity to the collection site, have a significant impact on the frequency of blood donation. Likewise, according to the results of the negative binomial model, among the 17 regions in the Province of Québec, there are five regions where blood donation incidence rate ratios (IRRs) are very high, that is, Abitibi-Témiscamingue (IRR, 1.77; 95% confidence interval [CI], 1.61-1.95); Bas-Saint-Laurent (IRR, 1.75; 95% CI, 1.59-1.93); Saguenay-Lac-Saint-Jean (IRR, 1.68; 95% CI, 1.53-1.84); Centre-du-Québec (IRR, 1.66; 95% CI, 1.51-1.83); and Chaudière-Appalaches (IRR, 1.62; 95% CI, 1.48-1.78). CONCLUSION: Such knowledge of the geography of blood donations makes it possible to better target certain regions when planning new blood drives, to ensure a constant blood supply.


Subject(s)
Blood Banks/statistics & numerical data , Blood Donors/statistics & numerical data , Databases, Factual/statistics & numerical data , Models, Statistical , Adolescent , Adult , Age Distribution , Aged , Female , Humans , Logistic Models , Male , Middle Aged , Quebec/epidemiology , Sex Distribution , Topography, Medical/statistics & numerical data , Young Adult
12.
Mem Inst Oswaldo Cruz ; 106 Suppl 1: 114-22, 2011 Aug.
Article in English | MEDLINE | ID: mdl-21881765

ABSTRACT

Malaria is currently one of the most serious public health problems in Colombia with an endemic/epidemic transmission pattern that has maintained endemic levels and an average of 105,000 annual clinical cases being reported over the last five years. Plasmodium vivax accounts for approximately 70% of reported cases with the remainder attributed almost exclusively to Plasmodium falciparum. A limited number of severe and complicated cases have resulted in mortality, which is a downward trend that has been maintained over the last few years. More than 90% of the malaria cases in Colombia are confined to 70 municipalities (about 7% of the total municipalities of Colombia), with high predominance (85%) in rural areas. The purpose of this paper is to review the progress of malaria-eradication activities and control measures over the past century within the eco-epidemiologic context of malaria transmission together with official consolidated morbidity and mortality reports. This review may contribute to the formulation of new antimalarial strategies and policies intended to achieve malaria elimination/eradication in Colombia and in the region.


Subject(s)
Endemic Diseases/prevention & control , Malaria, Falciparum/epidemiology , Malaria, Vivax/epidemiology , Age Distribution , Colombia/epidemiology , Endemic Diseases/statistics & numerical data , Geography , Humans , Incidence , Malaria, Falciparum/mortality , Malaria, Falciparum/prevention & control , Malaria, Vivax/mortality , Malaria, Vivax/prevention & control , Topography, Medical/statistics & numerical data
13.
Mem. Inst. Oswaldo Cruz ; 106(supl.1): 114-122, Aug. 2011. graf, mapas
Article in English | LILACS | ID: lil-597252

ABSTRACT

Malaria is currently one of the most serious public health problems in Colombia with an endemic/epidemic transmission pattern that has maintained endemic levels and an average of 105,000 annual clinical cases being reported over the last five years. Plasmodium vivax accounts for approximately 70 percent of reported cases with the remainder attributed almost exclusively to Plasmodium falciparum. A limited number of severe and complicated cases have resulted in mortality, which is a downward trend that has been maintained over the last few years. More than 90 percent of the malaria cases in Colombia are confined to 70 municipalities (about 7 percent of the total municipalities of Colombia), with high predominance (85 percent) in rural areas. The purpose of this paper is to review the progress of malaria-eradication activities and control measures over the past century within the eco-epidemiologic context of malaria transmission together with official consolidated morbidity and mortality reports. This review may contribute to the formulation of new antimalarial strategies and policies intended to achieve malaria elimination/eradication in Colombia and in the region.


Subject(s)
Humans , Endemic Diseases , Malaria, Falciparum , Malaria, Vivax , Age Distribution , Colombia , Endemic Diseases/statistics & numerical data , Geography , Incidence , Malaria, Falciparum/mortality , Malaria, Falciparum , Malaria, Vivax/mortality , Malaria, Vivax , Topography, Medical/statistics & numerical data
15.
Pediatr Blood Cancer ; 56(1): 58-64, 2011 Jan.
Article in English | MEDLINE | ID: mdl-21108440

ABSTRACT

BACKGROUND: Resource-rich countries tend to have a higher incidence of childhood acute lymphoblastic leukemia (ALL), whereas lower rates are seen in more deprived countries. This study describes the incidence of childhood acute leukemia in Brazil, an upper middle-income country, based on data from 16 population-based cancer registries (PBCRs). PROCEDURE: Data were examined from 16 PBCRs in Brazilian cities located in five geographical regions during the period from 1997 to 2004. Incidence rates were analyzed according to gender, age, and type of leukemia. The Wilcoxon test was performed to evaluate for gender-age based difference between by leukemia type. RESULTS: The median age-adjusted incidence rate (AAIR) of leukemia in children aged 0-14 years old was 53.3 per million. A different AAIR was found regarding ALL and myeloproliferative disorders (MPD) that ranged from 24.8 to 76.84 per 1,000,000 children. Manaus, although located in a poor area of Brazil, exhibited the highest AAIR (56.6 per million) of ALL. Goiania had the highest AAIR (24.5 per million) of MPD. The median age-specific incidence rate (ASIR) for the 16 Brazilian PBCRs demonstrated a marked peak in incidence of ALL at age 3 years old, in both genders. CONCLUSIONS: This population-based study of childhood leukemia demonstrates that substantial regional differences exist regarding the incidence of acute leukemia in Brazil, which warrants further ecological study.


Subject(s)
Precursor Cell Lymphoblastic Leukemia-Lymphoma/epidemiology , Topography, Medical/statistics & numerical data , Adolescent , Age Factors , Brazil/epidemiology , Child , Child, Preschool , Data Collection , Female , Humans , Incidence , Infant , Infant, Newborn , Male , Precursor Cell Lymphoblastic Leukemia-Lymphoma/etiology , Registries , Sex Factors , Socioeconomic Factors
16.
Geospat Health ; 4(2): 257-65, 2010 May.
Article in English | MEDLINE | ID: mdl-20503193

ABSTRACT

There is an increasing interest in the relationship between area-based disadvantage and obesity but the extent to which the poverty-obesity relationship remains constant across geographical areas remains unclear. We examined geographical variations in the relationship between poverty and obesity in Taiwan using geographically weighted regression (GWR). A representative sample of 27,293 Taiwanese adults (21 to 64 years old) from 262 townships was obtained from the 2001 Social Development Trend Survey on Health and Safety (SDSHS) in Taiwan. GWR revealed that there were local variations in the poverty-obesity relationship and that poverty was only significantly associated with obesity in less-developed areas. Significant relationship between poverty and obesity was found only in less-developed areas, suggesting that the impact of poverty on obesity is area-specific.


Subject(s)
Obesity/epidemiology , Poverty/statistics & numerical data , Topography, Medical/statistics & numerical data , Adult , Body Mass Index , Female , Health Status Disparities , Health Surveys , Humans , Linear Models , Male , Middle Aged , Models, Statistical , Prevalence , Regression Analysis , Risk Factors , Socioeconomic Factors , Statistics as Topic , Taiwan/epidemiology , Young Adult
17.
Europace ; 11(10): 1308-12, 2009 Oct.
Article in English | MEDLINE | ID: mdl-19797146

ABSTRACT

AIMS: There is marked geographical variation in implantable cardioverter defibrillator (ICD) implantation rates in England. This study examined factors which might explain this variation. METHODS AND RESULTS: Detailed data relating to 1510 patients who received an implanted defibrillator and who were reported to a national pacemaker and implantable defibrillator registry in 2002 were examined and correlated with factors which have been suggested as affecting ICD implantation. None of the factors examined, which included factors related both to the need for ICD implantation and service provision, in addition to socio-economic deprivation, was found to correlate with regional ICD implantation rates. CONCLUSION: There appears to have been no systematic planning of ICD services. Whether this has led to the marked regional variation and in inequity of service provision is not clear.


Subject(s)
Arrhythmias, Cardiac/mortality , Arrhythmias, Cardiac/prevention & control , Defibrillators, Implantable/supply & distribution , Defibrillators, Implantable/statistics & numerical data , Health Services Accessibility/statistics & numerical data , Healthcare Disparities/statistics & numerical data , Topography, Medical/statistics & numerical data , Age Distribution , Aged , Aged, 80 and over , Employment , England/epidemiology , Female , Humans , Male , Middle Aged , Practice Patterns, Physicians'/statistics & numerical data , Prevalence , Sex Distribution , Social Class
19.
Int J Health Geogr ; 7: 66, 2008 Dec 18.
Article in English | MEDLINE | ID: mdl-19094221

ABSTRACT

BACKGROUND: This study developed a multi-temporal analysis on the relationship between West Nile Virus (WNV) dissemination and environmental variables by using an integrated approach of remote sensing, GIS, and statistical techniques. WNV mosquito cases in seven months (April-October) of the six years (2002-2007) were collected in Indianapolis, USA. Epidemic curves were plotted to identify the temporal outbreaks of WNV. Spatial-temporal analysis and k-mean cluster analysis were further applied to determine the high-risk areas. Finally, the relationship between environmental variables and WNV outbreaks were examined by using Discriminant Analysis. RESULTS: The results show that the WNV epidemic curve reached its peak in August for all years in the study area except in 2007, where the peak was reached in July. WNV dissemination started from the central longitudinal corridor of the city and spread out to the east and west. Different years and seasons had different high-risk areas, but the southwest and southeast corners show the highest risk for WNV infection due to their high percentages of agriculture and water sources. CONCLUSION: Major environmental factors contributing to the outbreak of WNV in Indianapolis were the percentages of agriculture and water, total length of streams, and total size of wetlands. This study provides important information for urban public health prevention and management. It also contributes to the optimization of mosquito control and arrangement of future sampling efforts.


Subject(s)
Demography , Environmental Exposure/statistics & numerical data , Topography, Medical/statistics & numerical data , West Nile Fever/epidemiology , West Nile virus , Animals , Cluster Analysis , Environmental Exposure/prevention & control , Humans , Indiana/epidemiology , Mosquito Control/trends , Risk Factors , Time Factors , West Nile Fever/etiology , West Nile Fever/prevention & control
20.
Trans R Soc Trop Med Hyg ; 102(5): 471-9, 2008 May.
Article in English | MEDLINE | ID: mdl-18343470

ABSTRACT

The emerging virus strain termed highly pathogenic H5N1 avian influenza (HP-H5N1) has spread widely in the past decade and is now the focus of considerable concern in several sectors. We tested the hypothesis that spatial distributions of veterinary and human HP-H5N1 cases are related to coarse-scale environmental features in West Africa. We used ecological niche models to associate Nigerian HP-H5N1 occurrences with 1 km resolution digital data layers summarizing parameters of surface reflectance and landform. Predictive challenges included anticipating the spatial distribution of (i) random subsamples and (ii) spatially and temporally stratified subsamples of Nigerian occurrence data, and (iii) more limited occurrence data from across West Africa. In almost all tests, we found that HP-H5N1 cases were occurring under predictable environmental conditions, suggesting that elements of the transmission cycle have some form of ecological determination, here measured as differences in land-surface reflectance and plant phenology through the year. Considerable additional work is needed to establish how these differences affect HP-H5N1 transmission.


Subject(s)
Anseriformes/virology , Communicable Diseases, Emerging/transmission , Influenza A Virus, H5N1 Subtype , Influenza in Birds/transmission , Influenza, Human/transmission , Africa, Western/epidemiology , Algorithms , Animals , Communicable Diseases, Emerging/epidemiology , Ecosystem , Humans , Influenza in Birds/epidemiology , Influenza, Human/epidemiology , Nigeria/epidemiology , Predictive Value of Tests , Topography, Medical/statistics & numerical data
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