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 $), qualityadjusted life-years, incremental cost-effectiveness ratio, and other outcomes over the period 2006 to 2106. Results: On average, universal routine hepatitis A vaccination prevented 259,776 additional infections, 167,094 outpatient visits, 4781 hospitalizations, and 228 deaths annually. Compared with the regional vaccination policy, universal routine hepatitis A vaccination was cost saving. In scenario analysis, universal vaccination prevented 94,957 infections, 46,179 outpatient visits, 1286 hospitalizations, and 15 deaths annually and had an incremental cost-effectiveness ratio of$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 Científicas 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, Físicas y Naturales. Cátedra de Diversidad Animal I; Argentina. Consejo Nacional de Investigaciones Científicas 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