A study of the distribution and abundance of the adult malaria vector in western Kenya highlands

Background  

A sharp rise in the malaria mortality rate has been observed recently in western Kenya. Malaria is transmitted by mosquito vectors. Malaria control strategies can be more successful if the distribution and abundance of mosquito vectors is predicted. However, how mosquito vectors are distributed in space remain poor understood, and this question is rarely studied using spatial methods. This study aims to provide a better understanding of the distribution and abundance of mosquito vectors. To achieve this objective, spatial and non-spatial methods were employed. The data on the distribution of adult mosquitoes, and mosquito breeding habitats in a study area in western Kenya, and environmental variables were analyzed.     

Temporal and spatial stability of Anopheles gambiae larval habitat distribution in Western Kenya highlands

Background  

Localized mosquito larval habitat management and the use of larvicides have been proposed as important control tools in integrated malaria vector management programs. In order to optimize the utility of these tools, detailed knowledge of the spatial distribution patterns of mosquito larval habitats is crucial. However, the spatial and temporal changes of habitat distribution patterns under different climatic conditions are rarely quantified and their implications to larval control are unknown.     

Estimating the regional distribution of men who have sex with men (MSM) based on Internet surveys

Background  

Measurement of prevalence and incidence of infections in a hard to reach population like men who have sex with men (MSM) is hampered by its unknown size and regional distribution. Population-based surveys have recently been used to estimate the total number of MSM, but these surveys are usually not large enough to measure regional differences in the proportion of MSM in the population. We explored the use of the proportional regional distribution of participants of large internet-based surveys among MSM from Germany to estimate the regional distribution of MSM in Germany.     

Geostatistical evaluation of integrated marsh management impact on mosquito vectors using before-after-control-impact (BACI) design

Background  

In many parts of the world, salt marshes play a key ecological role as the interface between the marine and the terrestrial environments. Salt marshes are also exceedingly important for public health as larval habitat for mosquitoes that are vectors of disease and significant biting pests. Although grid ditching and pesticides have been effective in salt marsh mosquito control, marsh degradation and other environmental considerations compel a different approach. Targeted habitat modification and biological control methods known as Open Marsh Water Management (OMWM) had been proposed as a viable alternative to marsh-wide physical alterations and chemical control. However, traditional larval sampling techniques may not adequately assess the impacts of marsh management on mosquito larvae. To assess the effectiveness of integrated OMWM and marsh restoration techniques for mosquito control, we analyzed the results of a 5-year OMWM/marsh restoration project to determine changes in mosquito larval production using GIS and geostatistical methods.     

Rationale,design, and analysis of combined Brazilian household budget survey and food intake individual data

Background  

Data on food intake at the individual level and its statistical distribution in population groups defined by age, gender, or geographic areas are important in planning public health and nutrition programs. However, individual-based surveys in representative population samples are expensive to perform.     

Predicting outbreaks: a spatial risk assessment of West Nile virus in British Columbia

Background  

West Nile virus (WNv) has recently emerged as a health threat to the North American population. After the initial disease outbreak in New York City in 1999, WNv has spread widely and quickly across North America to every contiguous American state and Canadian province, with the exceptions of British Columbia (BC), Prince Edward Island and Newfoundland. In this study we develop models of mosquito population dynamics for Culex tarsalis and C. pipiens, and create a spatial risk assessment of WNv prior to its arrival in BC by creating a raster-based mosquito abundance model using basic geographic and temperature data. Among the parameters included in the model are spatial factors determined from the locations of BC Centre for Disease Control mosquito traps (e.g., distance of the trap from the closest wetland or lake), while other parameters were obtained from the literature. Factors not considered in the current assessment but which could influence the results are also discussed.     

Breast and cervical cancer screening among women in metropolitan areas of the United States by county-level commuting time to work and use of public transportation, 2004 and 2006

Background  

Commuting times and behaviors have been associated with a variety of chronic disease outcomes and health behaviors. We examined the relationships between ecologic measures of commuting time and use of public transportation in relation to breast and cervical cancer screening among women in U.S. metropolitan areas who participated in the 2004 and 2006 Behavioral Risk Factor Surveillance System (BRFSS) surveys.     

Smoking and mental illness: results from population surveys in Australia and the United States

Background  

Smoking has been associated with a range of mental disorders including schizophrenia, anxiety disorders and depression. People with mental illness have high rates of morbidity and mortality from smoking related illnesses such as cardiovascular disease, respiratory diseases and cancer. As many people who meet diagnostic criteria for mental disorders do not seek treatment for these conditions, we sought to investigate the relationship between mental illness and smoking in recent population-wide surveys.     

Eco-bio-social determinants of dengue vector breeding: a?multicountry study in urban and periurban Asia

Objective

To study dengue vector breeding patterns under a variety of conditions in public and private spaces; to explore the ecological, biological and social (eco-bio-social) factors involved in vector breeding and viral transmission, and to define the main implications for vector control.

Methods

In each of six Asian cities or periurban areas, a team randomly selected urban clusters for conducting standardized household surveys, neighbourhood background surveys and entomological surveys. They collected information on vector breeding sites, people’s knowledge, attitudes and practices surrounding dengue, and the characteristics of the study areas. All premises were inspected; larval indices were used to quantify vector breeding sites, and pupal counts were used to identify productive water container types and as a proxy measure for adult vector abundance.

Findings

The most productive vector breeding sites were outdoor water containers, particularly if uncovered, beneath shrubbery and unused for at least one week. Peridomestic and intradomestic areas were much more important for pupal production than commercial and public spaces other than schools and religious facilities. A complex but non-significant association was found between water supply and pupal counts, and lack of waste disposal services was associated with higher vector abundance in only one site. Greater knowledge about dengue and its transmission was associated with lower mosquito breeding and production. Vector control measures (mainly larviciding in one site) substantially reduced larval and pupal counts and “pushed” mosquito breeding to alternative containers.

Conclusion

Vector breeding and the production of adult Aedes aegypti are influenced by a complex interplay of factors. Thus, to achieve effective vector management, a public health response beyond routine larviciding or focal spraying is essential.     

Statistical modeling of volume of alcohol exposure for epidemiological studies of population health: the US example

Background  

Alcohol consumption is a major risk factor in the global burden of disease, with overall volume of exposure as the principal underlying dimension. Two main sources of data on volume of alcohol exposure are available: surveys and per capita consumption derived from routine statistics such as taxation. As both sources have significant problems, this paper presents an approach that triangulates information from both sources into disaggregated estimates in line with the overall level of per capita consumption.     

Health-related quality of life in inflammatory bowel disease measured with the generic 15D instrument

Objectives  

In many surveys, inflammatory bowel disease (IBD) has been shown to have a negative impact on health-related quality of life (HRQoL), especially when the disease is active. The purpose of this study was to compare a disease-specific HRQoL tool (Inflammatory Bowel Disease Questionnaire, IBDQ) and a generic HRQoL tool (15D) in a large cohort of IBD patients, to assess the ability of the 15D to detect differences in HRQoL between disease states and to compare the HRQoL of IBD patients with that of the general population.     

Identification and characterization of larval and adult anopheline mosquito habitats in the Republic of Korea: potential use of remotely sensed data to estimate mosquito distributions

Background  

Plasmodium vivax malaria reemerged in the Republic of Korea in 1993, with more than 2,000 cases reported in the northwestern part of the country over the last 10 years. To better assess the risk of malaria transmission we conducted a surveillance study to identify and characterize the habitats that produce potential Anopheles vector mosquitoes. Immature and adult mosquito collection data were incorporated into a Geographic Information System (GIS) along with remotely sensed satellite imagery, and imagery classified to land use to determine if remote sensing data could be used to estimate mosquito habitats.     

Measuring the health of the Indian elderly: evidence from National Sample Survey data

Background  

Comparable health measures across different sets of populations are essential for describing the distribution of health outcomes and assessing the impact of interventions on these outcomes. Self-reported health (SRH) is a commonly used indicator of health in household surveys and has been shown to be predictive of future mortality. However, the susceptibility of SRH to influence by individuals' expectations complicates its interpretation and undermines its usefulness.     

Establishing a follow-up of the Swiss MONICA participants (1984-1993): record linkage with census and mortality data

Background  

To assess the feasibility and quality of an anonymous linkage of 1) MONICA (MONItoring of trends and determinants in CArdiovscular disease, three waves between 1984 and 1993) data with 2) census and mortality records of the Swiss National Cohort in order to establish a mortality follow-up until 2008. Many countries feature the defect of lacking general population cohorts because they have missed to provide for follow-up information of health surveys.     

Do postage stamps versus pre-paid envelopes increase responses to patient mail surveys? A randomised controlled trial

Background  

Studies largely from the market research field suggest that the inclusion of a stamped addressed envelope, rather than a pre-paid business reply, increases the response rate to mail surveys. The evidence that this is also the case regarding patient mail surveys is limited.     

A quantitative analysis of the socio-economic determinants of health seeking behaviour related to bancroftian filariasis and its impact on elimination: a case-control study in Pondicherry,India

Aim  Knowledge, belief, attitude and values shape the health behaviour and all these can help in deciding whether to behave in one way or the other. Therefore, the underlying relationship between knowledge, attitude and practice (KAP) regarding causation, prevention and treatment of filarial disease is studied separately for affected and normal individuals. Methods  KAP aspects of the disease were measured using a structured questionnaire and methods were designed to quantify all the variables for which data were collected. A salient feature of the method is the judicious assignment of scores to individual items and summing the scores across items for appropriate standardization. Results  Multiple regression analyses indicate that the knowledge on disease treatment, mode of transmission, prevention and income explain about 29% of variation that occurs in knowledge on mosquito breeding and control. Standard of living, knowledge on disease transmission and knowledge on mosquito breeding and control explain 23% of variation in practice measures against mosquito biting. Knowledge gained on disease treatment, prevention, diagnosis and knowledge on mosquito breeding and control is greatly improving the prevention practices against mosquito breeding and control. Interpretation  The results reveal that through imparting health education on disease prevention, diagnosis and treatment, awareness about mosquito breeding and control can be achieved.

Geographical variation of cerebrovascular disease in New York State: the correlation with income

Background  

Income is known to be associated with cerebrovascular disease; however, little is known about the more detailed relationship between cerebrovascular disease and income. We examined the hypothesis that the geographical distribution of cerebrovascular disease in New York State may be predicted by a nonlinear model using income as a surrogate socioeconomic risk factor.     

Malaria mosquito control using edible fish in western Kenya: preliminary findings of a controlled study

Background  

Biological control methods are once again being given much research focus for malaria vector control. This is largely due to the emerging threat of strong resistance to pesticides. Larvivorous fish have been used for over 100 years in mosquito control and many species have proved effective. In the western Kenyan highlands the larvivorous fish Oreochromis niloticus L. (Perciformes: Cichlidae) (formerly Tilapia nilotica) is commonly farmed and eaten but has not been previously tested in the field for malaria mosquito control.     

Participatory mapping of target areas to enable operational larval source management to suppress malaria vector mosquitoes in Dar es Salaam,Tanzania

Background  

Half of the population of Africa will soon live in towns and cities where it can be protected from malaria by controlling aquatic stages of mosquitoes. Rigorous but affordable and scaleable methods for mapping and managing mosquito habitats are required to enable effective larval control in urban Africa.     

Accuracy of responses from postal surveys about continuing medical education and information behavior: experiences from a survey among German diabetologists

Background  

Postal surveys are a popular instrument for studies about continuing medical education habits. But little is known about the accuracy of responses in such surveys. The objective of this study was to quantify the magnitude of inaccurate responses in a postal survey among physicians.