1,985 research outputs found
Use of satellite imagery in constructing a household GIS database for health studies in Karachi, Pakistan
BACKGROUND: Household-level geographic information systems (GIS) database are usually constructed using the geographic positioning system (GPS). In some research settings, GPS receivers may fail to capture accurate readings due to structural barriers such as tall buildings. We faced this problem when constructing a household GIS database for research sites in Karachi, Pakistan because the sites are comprised of congested groups of multi-storied building and narrow lanes. In order to overcome this problem, we used high resolution satellite imagery (IKONOS) to extract relevant geographic information. RESULTS: The use of IKONOS satellite imagery allowed us to construct an accurate household GIS database, which included the size and orientation of the houses. The GIS database was then merged with health data, and spatial analysis of health was possible. CONCLUSIONS: The methodological issues introduced in this paper provide solutions to the technical barriers in constructing household GIS database in a heavily populated urban setting
Comparisons of predictors for typhoid and paratyphoid fever in Kolkata, India
BACKGROUND: Exposure of the individual to contaminated food or water correlates closely with the risk for enteric fever. Since public health interventions such as water improvement or vaccination campaigns are implemented for groups of individuals we were interested whether risk factors not only for the individual but for households, neighbourhoods and larger areas can be recognised? METHODS: We conducted a large enteric fever surveillance study and analyzed factors which correlate with enteric fever on an individual level and factors associated with high and low risk areas with enteric fever incidence. Individual level data were linked to a population based geographic information systems. Individual and household level variables were fitted in Generalized Estimating Equations (GEE) with the logit link function to take into account the likelihood that household factors correlated within household members. RESULTS: Over a 12-month period 80 typhoid fever cases and 47 paratyphoid fever cases were detected among 56,946 residents in two bustees (slums) of Kolkata, India. The incidence of paratyphoid fever was lower (0.8/1000/year), and the mean age of paratyphoid patients was older (17.1 years) than for typhoid fever (incidence 1.4/1000/year, mean age 14.7 years). Residents in areas with a high risk for typhoid fever had lower literacy rates and economic status, bigger household size, and resided closer to waterbodies and study treatment centers than residents in low risk areas. CONCLUSION: There was a close correlation between the characteristics detected based on individual cases and characteristics associated with high incidence areas. Because the comparison of risk factors of populations living in high versus low risk areas is statistically very powerful this methodology holds promise to detect risk factors associated with diseases using geographic information systems
A Cost-Benefit Analysis of Typhoid Fever Immunization Programmes in an Indian Urban Slum Community
Many economic analyses of immunization programmes focus on the benefits
in terms of public-sector cost savings, but do not incorporate
estimates of the private cost savings that individuals receive from
vaccination. This paper considers the implications of Bahl et al.'s
cost-of-illness estimates for typhoid immunization policy by examining
how community-level incidence estimates and information on distribution
of costs of illness among patients and the public-health sector can be
used in the economic analysis of vaccination-programme options. The
findings illustrate why typhoid vaccination programmes may often appear
to be unattractive to public-health officials who adopt a public
budgetary perspective. Under many plausible sets of assumptions,
public-sector expenditure on typhoid vaccination does not yield
comparable public-sector cost savings. If public-health officials adopt
a societal perspective on the economic benefits of vaccination, there
are many situations in which different vaccination programmes will make
economic sense. The findings show that this is especially true when
public decision-makers recognize that (a) the incidence of typhoid
fever is underestimated by blood culture-positive cases and (b) avoided
costs of illness represent a significant underestimate of the actual
economic benefits to individuals of vaccination
Immune responses to Vi capsular polysaccharide typhoid vaccine in children 2 to 16 years old in Karachi, Pakistan, and Kolkata, India
The geometric mean concentration (GMC) and the proportion maintaining a protective level (150 enzyme-linked immunosorbent assay (ELISA) units [ELU]/ml) 2 years following a single dose of 25 μg of injectable Vi capsular polysaccharide typhoid vaccine was measured against that of the control hepatitis A vaccine in children 2 to 16 years old in cluster randomized trials in Karachi and Kolkata. The GMC for the Vi group (1,428 ELU/ml) was statistically significantly different from the GMC of the control hepatitis A vaccine group (86 ELU/ml) after 6 weeks. A total of 117 children (95.1%) in the Vi group and 9 (7.5%) in the hepatitis A group showed a 4-fold rise in Vi IgG antibody concentrations at 6 weeks (P \u3c 0.01). Protective antibody levels remained significantly different between the two groups at 2 years (38% in the Vi vaccine groups and 6% in the hepatitis A group [P \u3c 0.01]). A very small proportion of younger children (2 to 5 years old) maintained protective Vi IgG antibody levels at 2 years, a result that was not statistically significantly different compared to that for the hepatitis A group (38.1% versus 10.5%). The GMCs of the Vi IgG antibody after 2 years were 133 ELU/ml for children 2 t
Costs of Illness Due to Typhoid Fever in an Indian Urban Slum Community: Implications for Vaccination Policy
Data on the burden of disease, costs of illness, and cost-effectiveness
of vaccines are needed to facilitate the use of available anti-typhoid
vaccines in developing countries. This one-year prospective
surveillance was carried out in an urban slum community in Delhi,
India, to estimate the costs of illness for cases of typhoid fever.
Ninety-eight culture-positive typhoid, 31 culture-positive paratyphoid,
and 94 culture-negative cases with clinical typhoid syndrome were
identified during the surveillance. Estimates of costs of illness were
based on data collected through weekly interviews conducted at home for
three months following diagnosis. Private costs included the sum of
direct medical, direct non-medical, and indirect costs. Non-patient
(public) costs included costs of outpatient visits, hospitalizations,
laboratory tests, and medicines provided free of charge to the
families. The mean cost per episode of blood culture-confirmed typhoid
fever was 3,597 Indian Rupees (US$ 1=INR 35.5) (SD 5,833);
hospitalization increased the costs by several folds (INR 18,131, SD
11,218, p<0.0001). The private and non-patient costs of illness were
similar (INR 1,732, SD 1,589, and INR 1,865, SD 5,154 respectively,
p=0.8095). The total private and non-patient ex-ante costs, i.e.
expected annual losses for each individual, were higher for children
aged 2-5 years (INR 154) than for those aged 5-19 years (INR 32), 0-2
year(s) (INR 25), and 19-40 years (INR 2). The study highlights the
need for affordable typhoid vaccines efficacious at 2-5 years of age.
Currently-available Vi vaccine is affordable but is unlikely to be
efficacious in the first two years of life. Ways must be found to make
Vi-conjugate vaccine, which is efficacious at this age, available to
children of developing-countries
Organizational aspects and implementation of data systems in large-scale epidemiological studies in less developed countries
BACKGROUND: In the conduct of epidemiological studies in less developed countries, while great emphasis is placed on study design, data collection, and analysis, often little attention is paid to data management. As a consequence, investigators working in these countries frequently face challenges in cleaning, analyzing and interpreting data. In most research settings, the data management team is formed with temporary and unskilled persons. A proper working environment and training or guidance in constructing a reliable database is rarely available. There is little information available that describes data management problems and solutions to those problems. Usually a line or two can be obtained in the methods section of research papers stating that the data are doubly-entered and that outliers and inconsistencies were removed from the data. Such information provides little assurance that the data are reliable. There are several issues in data management that if not properly practiced may create an unreliable database, and outcomes of this database will be spurious. RESULTS: We have outlined the data management practices for epidemiological studies that we have modeled for our research sites in seven Asian countries and one African country. CONCLUSION: Information from this model data management structure may help others construct reliable databases for large-scale epidemiological studies in less developed countries
Public Health Impact and Cost-Effectiveness of Hepatitis A Vaccination in the United States: A Disease Transmission Dynamic Modeling Approach
Objective: To assess the population-level impact and costeffectiveness of hepatitis A vaccination programs in the United States. Methods: We developed an age-structured population model of hepatitis A transmission dynamics to evaluate two policies of administering a twodose hepatitis A vaccine to children aged 12 to 18 months: 1) universal routine vaccination as recommended by the Advisory Committee on Immunization Practices in 2006 and 2) Advisory Committee on Immunization Practices's previous regional policy of routine vaccination of children living in states with high hepatitis A incidence. Inputs were obtained from the published literature, public sources, and clinical trial data. The model was fitted to hepatitis A seroprevalence (National Health and Nutrition Examination Survey II and III) and reported incidence from the National Notifiable Diseases Surveillance System (1980)(1981)(1982)(1983)(1984)(1985)(1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995). We used a societal perspective and projected costs (in 2013 US 21,223/quality-adjusted life-year when herd protection was ignored. Conclusions: Our model predicted that universal childhood hepatitis A vaccination led to significant reductions in hepatitis A mortality and morbidity. Consequently, universal vaccination was cost saving compared with a regional vaccination policy. Herd protection effects of hepatitis A vaccination programs had a significant impact on hepatitis A mortality, morbidity, and cost-effectiveness ratios
The Role of Epidemiology in the Introduction of Vi Polysaccharide Typhoid Fever Vaccines in Asia
Despite the availability of at least two licensed typhoid fever
vaccines-injectable sub-unit Vi polysaccharide vaccine and live, oral
Ty21a vaccine-for the last decade, these vaccines have not been widely
introduced in public-health programmes in countries endemic for typhoid
fever. The goal of the multidisciplinary DOMI (Diseases of the Most
Impoverished) typhoid fever programme is to generate policy-relevant
data to support public decision-making regarding the introduction of Vi
polysaccharide typhoid fever immunization programmes in China, Viet
Nam, Pakistan, India, Bangladesh, and Indonesia. Through
epidemiological studies, the DOMI Programme is generating these data
and is offering a model for the accelerated, rational introduction of
new vaccines into health programmes in low-income countries. Practical
and specific examples of the role of epidemiology are described in this
paper. These examples cover: (a) selection of available typhoid fever
vaccines to be introduced in the programme, (b) generation of
policy-relevant data, (c) providing the 'backbone' for the
implementation of other multidisciplinary projects, and (d) generation
of unexpected but useful information relevant for the introduction of
vaccines. Epidemiological studies contribute to all stages of
development of vaccine evaluation and introduction
Rumikiru, n. gen. (Scorpiones: Bothriuridae), a new scorpion genus from the Atacama Desert
Rumikiru, n. gen., a new bothriurid scorpion genus from the coastal Atacama Desert, Chile, is described. This is the first scorpion genus endemic to northern Chile. It is most closely related to Pachakutej Ochoa, 2004, from the inter-Andean valleys of Peru. Orobothriurus lourencoi Ojanguren-Affilastro, 2003, is transferred to the new genus and redescribed, creating Rumikiru lourencoi (Ojanguren-Affilastro, 2003), n. comb., and a second species of the genus, Rumikiru atacama, n. sp., is described.Fil: Ojanguren Affilastro, Andres Alejandro. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Mattoni, Camilo Ivan. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, FÃsicas y Naturales. Cátedra de Diversidad Animal I; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Ochoa, José A.. Universidade de Sao Paulo; Brasil. Universidad Nacional de San Antonio Abad del Cusco. Museo de Historia Natural; PerúFil: Prendini, Lorenzo. American Museum Of Natural History; Estados Unido
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