Analysis of social epidemiology research on infectious diseases: historical patterns and future opportunities

Population Neuroscience: Principles and Advances

In population neuroscience, three disciplines come together to advance our knowledge of factors that shape the human brain: neuroscience, genetics, and epidemiology (Paus, Human Brain Mapping 31:891-903, 2010). Here, I will come back to some of the background material reviewed in more detail in our previous book (Paus, Population Neuroscience, 2013), followed by a brief overview of current advances and challenges faced by this integrative approach.

Exposure, Susceptibility, and Recovery: A Framework for Examining the Intersection of the Social and Physical Environments and Infectious Disease Risk

Despite well-documented evidence that structurally disadvantaged populations are disproportionately affected by infectious diseases, our understanding of the pathways that connect structural disadvantage to the burden of infectious diseases is limited. We propose a conceptual framework to facilitate more rigorous examination and testing of hypothesized mechanisms through which social and environmental factors shape the burden of infectious diseases and lead to persistent inequities. Drawing upon the principles laid out by Link and Phelan in their landmark paper on social conditions (J Health Soc Behav. 1995;(spec no.):80-94), we offer an explication of potential pathways through which structural disadvantage (e.g., racism, sexism, and economic deprivation) operates to produce infectious disease inequities. Specifically, we describe how the social environment affects an individual's risk of infectious disease by 1) increasing exposure to infectious pathogens and 2) increasing susceptibility to infection. This framework will facilitate both the systematic examination of the ways in which structural disadvantage shapes the burden of infectious disease and the design of interventions that can disrupt these pathways.

Interventions on Socioeconomic and Racial Inequities in Respiratory Pandemics: a Rapid Systematic Review

Purpose of Review

Racial and socioeconomic inequities in respiratory pandemics have been consistently documented, but little official guidance exists on effective action to prevent these. We systematically reviewed quantitative evaluations of (real or simulated) interventions targeting racial and socioeconomic inequities in respiratory pandemic outcomes.

Recent Findings

Our systematic search returned 10,208 records, of which 5 met inclusion criteria, including observational (n = 1), randomized trial (n = 1), and simulation (n = 3) studies. Interventions studied included vaccination parity, antiviral distribution, school closure, disinfection, personal protective equipment, and paid sick leave, with a focus on Black (n = 3) and/or Latinx (n = 4) or low-SES (n = 2) communities. Results are suggestive that these interventions might be effective at reducing racial and/or SES disparities in pandemics.

Summary

There is a dearth of research on strategies to reduce pandemic disparities. We provide theory-driven, concrete suggestions for incorporating equity into intervention research for pandemic preparedness, including a focus on social and economic policies.

Exploring for Municipality-Level Socioeconomic Variables Related to Zika Virus Incidence in Colombia

Colombia experienced an outbreak of Zika virus infection during September 2015 until July 2016. This study aimed to identify the socioeconomic factors that at the municipality level correlate with this outbreak and therefore could have influenced its incidence. An analysis of publicly available, municipality-aggregated data related to eight potential explanatory socioeconomic variables was conducted. These variables are school dropout, low energy strata, social security system, savings capacity, tax, resources, investment, and debt. The response variable of interest in this study is the number of reported cases of Zika virus infection per people (projected) per square kilometer. Binomial regression models were performed. Results show that the best predictor variables of Zika virus occurrence, assuming an expected inverse relationship with socioeconomic status, are "school", "energy", and "savings". Contrary to expectations, proxies of socioeconomic status such as "investment", "tax", and "resources" were associated with an increase in the occurrence of Zika virus infection, while no association was detected for "social security" and "debt". Energy stratification, school dropout rate, and the percentage of the municipality's income that is saved conformed to the hypothesized inverse relationship between socioeconomic standing and Zika occurrence. As such, this study suggests these factors should be considered in Zika risk modeling.

Determinants of Preventive Behaviors in Response to the COVID-19 Pandemic in France: Comparing the Sociocultural, Psychosocial, and Social Cognitive Explanations

In absence of effective pharmaceutical treatments, the individual's compliance with a series of behavioral recommendations provided by the public health authorities play a critical role in the control and prevention of SARS-CoV2 infection. However, we still do not know much about the rate and determinants of adoption of the recommended health behaviors. This paper examines the compliance with the main behavioral recommendations, and compares sociocultural, psychosocial, and social cognitive explanations for its variation in the French population. Based on the current literature, these 3 categories of factors were identified as potential determinants of individual differences in the health preventive behaviors. The data used for these analyses are drawn from 2 cross-sectional studies (N = 2,000 in survey 1 and 2,003 in survey 2) conducted after the lockdown and before the peak of the COVID-19 epidemic in France. The participants were drawn from a larger internet consumer panel where recruitment was stratified to generate a socio-demographically representative sample of the French adult population. Overall, the results show a very high rate of compliance with the behavioral recommendations among the participants. A hierarchical regression analysis was then performed to assess the potential explanatory power of these approaches in complying with these recommendations by successively entering sociocultural factors, psychosocial factors, social cognitive factors in the model. Only the inclusion of the cognitive variables substantially increased the explained variance of the self-reported adoption of preventive behaviors (R 2 change = 23% in survey 1 and 2), providing better support for the social cognitive than the sociocultural and psychosocial explanations.

Social patterning of acute respiratory illnesses in the Household Influenza Vaccine Evaluation (HIVE) Study 2014-2015

Social patterning of infectious diseases is increasingly recognised. Previous studies of social determinants of acute respiratory illness (ARI) have found that highly educated and lower income families experience more illnesses. Subjective social status (SSS) has also been linked to symptomatic ARI, but the association may be confounded by household composition. We examined SSS and ARI in the Household Influenza Vaccine Evaluation (HIVE) Study in 2014–2015. We used SSS as a marker of social disadvantage and created a workplace disadvantage score for working adults. We examined the association between these measures and ARI incidence using mixed-effects Poisson regression models with random intercepts to account for household clustering. In univariate analyses, mean ARI was higher among children <5 years old (P < 0.001), and females (P = 0.004) at the individual level. At the household level, mean ARI was higher for households with at least one child <5 years than for those without (P = 0.002). In adjusted models, individuals in the lowest tertile of SSS had borderline significantly higher rates of ARI than those in the highest tertile (incidence rate ratio (IRR) 1.34, 95% confidence interval (CI) 0.98–1.92). Households in the lowest tertile of SSS had significantly higher ARI incidence in household-level models (IRR 1.46, 95% CI 1.05–2.03). We observed no association between workplace disadvantage and ARI. We detected an increase in the incidence of ARI for households with low SSS compared with those with high SSS, suggesting that socio-economic position has a meaningful impact on ARI incidence.

Mind your Language: Discursive Practices Produce Unequal Power and Control Over Infectious Disease: A Critical Discourse Analysis

BACKGROUND

Power, socioeconomic inequalities, and poverty are recognized as some of the fundamental determinants of differences in vulnerability of societies to infectious disease threats. The economic south is carrying a higher burden than those in the economic north. This raises questions about whether social preventions and biomedical preventions for infectious disease are given equal consideration, and about social institutions and structures that frame the debate about infectious disease. This article examines how institutionalized ways of talking about infectious disease reinforces, creates, and sustains health inequalities.

METHODS

Critical discourse analysis was considered to be epistemologically and ontologically consistent with the aims and context of this study.

RESULTS

The study examined three types of infectious disease: • Emerging infectious diseases/pathogens • Neglected tropical diseases • Vector-borne infections. Examination revealed that poverty is the most common determinant of all three.

CONCLUSIONS

A sustainable reduction in infectious disease in the southern countries is most likely to be achieved through tackling socioeconomic determinants. There is a need for a change in the discourse on infectious disease, and adopt a discourse that promotes self-determination, rather than one that reinforces the hero-victim scenario and power inequalities.

A Spatial Analysis of Health Disparities Associated with Antibiotic Resistant Infections in Children Living in Atlanta (2002-2010)

Background

Antibiotic resistant bacteria like community-onset methicillin resistant Staphylococcus aureus (CO-MRSA) have continued to cause infections in children at alarming rates and are associated with health disparities. Geospatial analyses of individual and area level data can enhance disease surveillance and identify socio-demographic and geographic indicators to explain CO-MRSA disease transmission patterns and risks.

Methods

A case control epidemiology approach was undertaken to compare children with CO-MRSA to a noninfectious condition (unintentional traumatic brain injury (uTBI)). In order to better understand the impact of place based risks in developing these types of infections, data from electronic health records (EHR) were obtained from CO-MRSA cases and compared to EHR data from controls (uTBI). US Census data was used to determine area level data. Multi-level statistical models were performed using risk factors determined a priori and geospatial analyses were conducted and mapped.

Results

From 2002-2010, 4,613 with CO-MRSA and 34,758 with uTBI were seen from two pediatric hospitals in Atlanta, Georgia. Hispanic children had reduced odds of infection; females and public health insurance were more likely to have CO-MRSA. Spatial analyses indicate significant 'hot spots' for CO-MRSA and the overall spatial cluster locations, differed between CO-MRSA cases and uTBI controls.

Conclusions

Differences exist in race, age, and type of health insurance between CO-MRSA cases compared to noninfectious control group. Geographic clustering of cases is distinct from controls, suggesting placed based factors impact risk for CO-MRSA infection.

Sociodemographic variation in the oral microbiome

PURPOSE

Variations in the oral microbiome are potentially implicated in social inequalities in oral disease, cancers, and metabolic disease. We describe sociodemographic variation of oral microbiomes in a diverse sample.

METHODS

We performed 16S rRNA sequencing on mouthwash specimens in a subsample (n = 282) of the 2013-2014 population-based New York City Health and Nutrition Examination Study. We examined differential abundance of 216 operational taxonomic units, and alpha and beta diversity by age, sex, income, education, nativity, and race/ethnicity. For comparison, we examined differential abundance by diet, smoking status, and oral health behaviors.

RESULTS

Sixty-nine operational taxonomic units were differentially abundant by any sociodemographic variable (false discovery rate < 0.01), including 27 by race/ethnicity, 21 by family income, 19 by education, 3 by sex. We found 49 differentially abundant by smoking status, 23 by diet, 12 by oral health behaviors. Genera differing for multiple sociodemographic characteristics included Lactobacillus, Prevotella, Porphyromonas, Fusobacterium.

CONCLUSIONS

We identified oral microbiome variation consistent with health inequalities, more taxa differing by race/ethnicity than diet, and more by SES variables than oral health behaviors. Investigation is warranted into possible mediating effects of the oral microbiome in social disparities in oral and metabolic diseases and cancers.

Neighbourhood influence on the fourth dose of diphtheria-tetanus-pertussis vaccination

OBJECTIVES

Using 542,159 vaccination records from children born between April 1, 2007, and March 31, 2012, in the Michigan Care Improvement Registry and data from the American Community Survey, we determine if neighbourhood-level characteristics at the Census tract level and block level are associated with low uptake of the fourth dose of diphtheria-tetanus-acellular pertussis vaccine (DTaP4).

STUDY DESIGN

This study was a cross-sectional study.

METHODS

We used exploratory factor analysis to determine important socio-economic factors at the Census block level and tract level. We then used generalised estimating equations to test the relationship between block- and tract-level socio-economic factors and DTaP4 uptake.

RESULTS

DTaP4 coverage was 88.6% (95% confidence interval [CI]: 88.4%-88.7%) in Michigan. At the Census tract level, two factors surfaced as important for DTaP4 vaccination: 'affluence' (Cronbach's alpha = 0.88) and 'socio-economic disadvantage' (Cronbach's alpha = 0.89). At the Census block level, one factor was important: 'affluence' (Cronbach's alpha = 0.90). Affluence may relate to knowledge about medical exemptions and antivaccination sentiment, while socio-economic disadvantage may indicate limited access to healthcare resources. Children in high-affluence tracts had 1.08% lower vaccination coverage (95% CI: -1.62% to -0.55%) than children in low affluence tracts. Children in low socio-economic disadvantage tracts had 2.92% higher coverage than children in high socio-economic disadvantage tracts (95% CI: 2.58%-3.26%).

CONCLUSIONS

This study articulates the need to further understand the contribution of neighbourhood-level characteristics, from both affluent and socioeconomically disadvantaged areas to low vaccination rates. Developing a better understanding of these social environmental factors will help determine useful community-level interventions to improve vaccination rates and reduce disease burden.

General contextual effects on neglected tropical disease risk in rural Kenya

The neglected tropical diseases (NTDs) are characterized by their tendency to cluster within groups of people, typically the poorest and most marginalized. Despite this, measures of clustering, such as within-group correlation or between-group heterogeneity, are rarely reported from community-based studies of NTD risk. We describe a general contextual analysis that uses multi-level models to partition and quantify variation in individual NTD risk at multiple grouping levels in rural Kenya. The importance of general contextual effects (GCE) in structuring variation in individual infection with Schistosoma mansoni, the soil-transmitted helminths, Taenia species, and Entamoeba histolytica/dispar was examined at the household-, sublocation- and constituency-levels using variance partition/intra-class correlation co-efficients and median odds ratios. These were compared with GCE for HIV, Plasmodium falciparum and Mycobacterium tuberculosis. The role of place of residence in shaping infection risk was further assessed using the spatial scan statistic. Individuals from the same household showed correlation in infection for all pathogens, and this was consistently highest for the gastrointestinal helminths. The lowest levels of household clustering were observed for E. histolytica/dispar, P. falciparum and M. tuberculosis. Substantial heterogeneity in individual infection risk was observed between sublocations for S. mansoni and Taenia solium cysticercosis and between constituencies for infection with S. mansoni, Trichuris trichiura and Ascaris lumbricoides. Large overlapping spatial clusters were detected for S. mansoni, T. trichiura, A. lumbricoides, and Taenia spp., which overlapped a large cluster of elevated HIV risk. Important place-based heterogeneities in infection risk exist in this community, and these GCEs are greater for the NTDs and HIV than for TB and malaria. Our findings suggest that broad-scale contextual drivers shape infectious disease risk in this population, but these effects operate at different grouping-levels for different pathogens. A general contextual analysis can provide a foundation for understanding the complex ecology of NTDs and contribute to the targeting of interventions.

A quantitative exploration of nomadic pastoralists' knowledge and practices towards Rift Valley fever in Niger State, North-central Nigeria: The associated socio-cultural drivers

Rift Valley fever (RVF) is a vector-borne re-emerging viral zoonosis that mainly affects poor and marginalized populations in Africa and the Middle East. The study assessed pastoralists' knowledge/awareness and preventive measures towards RVF in Fulani nomadic pastoral communities of Niger State, North-central Nigeria. An interview questionnaire-based cross-sectional survey was conducted in randomly selected 403 Fulani nomadic pastoral households. Descriptive and analytical statistical analyses were performed. About 97% (389/403) of the pastoralists responded. Majority (74.0%) of them was males and 26.0% was females, while most (65.3%) did not possess formal education. About 85% and 77% of respondents mentioned high mortality in newborns and abortions in pregnant cows, respectively, as signs of RVF in cattle. Also, 50.6% of respondents mentioned high fever as RVF symptoms in humans, while 36.5% reported headache. Pastoralists in age group 70-99 years (OR: 2.69; 95% CI: 1.14, 6.33) and those with tertiary education (OR: 2.53; 95% CI: 1.06, 5.99) were more likely to possess satisfactory knowledge about RVF than others. Extensive husbandry system (OR: 6.16; 95% CI: 3.46, 10.97) as well as culture of borrowing and loaning of cattle (OR: 27.00; 95% CI: 12.67, 57.52) were more likely to influenced RVF occurrence in herds compared to other factors. The survey revealed gaps in levels of knowledge and practices regarding RVF among pastoralists. Socio-cultural activities were key social drivers for RVF occurrence in pastoral herds. The gaps, influenced by socio-demographic and cultural factors, necessitate the need for multidisciplinary approach including anthropologists in RVF preventive education for the pastoralists. Also, cross-disciplinary studies that would increase understanding of social determinants of re-emerging zoonotic diseases are encouraged.

Towards a critical epidemiology approach for applied sexual health research

Critical approaches may benefit epidemiological studies of sexual health. This article proposes a critical approach, reconcilable with social epidemiological enquiry. Key aims of critical epidemiology for sexual health are identified, from which three criticisms of practice emerge: (1) lack of attention to socio-cultural contexts, (2) construction of ‘risk’ as residing in the individual and (3) enactment of public health agendas which privilege and pathologise certain behaviours. These reflect and construct an apolitical understanding of population health. This article proposes features of a critical epidemiology that represent a morally driven re-envisioning of the focus, analysis and interpretation of epidemiological studies of sexual health.

The Modern Profile of Tuberculosis: Developing the TB Social Survey to understand contemporary social patterns in tuberculosis

Social disparities in tuberculosis have been documented for decades, yet to date there has not been a comprehensive study to examine the contemporary causes of these disparities. Local public health departments, and particularly public health nursing staff are charged with delivering directly observed therapy to individuals with tuberculosis disease. As a result of the frequency and duration of treatment, practitioners delivering therapy are often well-acquainted with the lives and challenges of their constituents. Thus, through these practitioners there exists a deep repository of knowledge on the drivers of social disparities in tuberculosis disease. Partnering with local public health departments, we developed a survey instrument aimed at understanding the social profile of individuals with tuberculosis disease in metropolitan Detroit, Michigan. We discuss the development and implementation of the survey instrument as well as challenges in developing partnerships between academic researchers and local public health practitioners. This study can serve as a framework for both academic researchers and public health practitioners interested in addressing social disparities in infectious disease.

Race and nativity are major determinants of tuberculosis in the U.S.: evidence of health disparities in tuberculosis incidence in Michigan, 2004-2012

Background

The incidence of TB in Michigan was 1.5 per 100,000 people in 2012, roughly half the U.S. incidence. Despite successes in TB control, disparities in TB still exist in Michigan, particularly by race, age, and nativity. A major challenge in understanding disparities in TB burden is distinguishing between TB cases resulting from recent transmission and those resulting from reactivation of latent TB infection, information critical to tailoring control strategies. We examined nine-year trends in tuberculosis (TB) incidence patterns for the entire population of Michigan, and within demographic subgroups.

Methods

Using a cross-sectional study of TB surveillance data, we analyzed 1254 TB cases reported in Michigan during 2004–2012. Cases included were those for whom both spoligotyping and 12-locus-MIRU-VNTR results were available. Using a combination of the genotyping information and time of diagnosis, we then classified cases as resulting from either recent transmission or reactivation of latent TB infection. We used multivariable negative binomial regression models to study trends in the TB incidence rate for the entire population and by race, nativity, gender, and age.

Results

Overall, the incidence rate of TB declined by an average of 8% per year—11% among recently transmitted cases, and 9% among reactivation cases. For recently transmitted disease, Blacks had an average incidence rate 25 times greater than Whites, after controlling for nativity, gender, and age. For disease resulting from latent TB infection Asians had an average incidence rate 24 times greater than Whites, after controlling for nativity, gender, and age.

Conclusions

Disparities in incidence persist despite ongoing TB control efforts. Greater disparities were observed by race and nativity demonstrating some of the ways that TB incidence is socially patterned. Reducing these disparities will require a multi-faceted approach encompassing the social and environmental contexts of high-risk populations.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-017-4461-y) contains supplementary material, which is available to authorized users.

Area-Level Deprivation and Adverse Consequences in People With Substance Use Disorders: Findings From the Psychiatric and Addictive Dual Disorder in Italy (PADDI) Study

BACKGROUND

Environmental factors may operate with individual ones to influence the risk of substance use. Research has focused on severe adverse consequences influenced by contextual variables. However, the literature on community level factors influencing substance use behaviors is relatively limited across Europe so far.

OBJECTIVE

We capitalized on data from a National survey, exploring individual and contextual characteristics, to study adverse consequences among people with substance use disorders.

METHODS

The impact of area-level deprivation on nonfatal overdose, hepatitis C or B infections, and major involvement with the criminal justice system, was explored. Logistic regression models with cluster-robust errors, modeling subject-level and area-level effects, were used.

RESULTS

Living in deprived and intermediate areas, as compared with affluent ones, was associated with greater likelihood of both nonfatal overdose and jail sentences longer than 6 months, though not of active viral hepatitis.

CONCLUSIONS

Area-level deprivation may play an important role in determining adverse consequences in people with substance use disorders, also after controlling for individual-level characteristics. More research is needed to understand the aspects of social and physical environments that matter for drug outcomes before effective policy and research interventions can be developed.

Analyses of infectious disease patterns and drivers largely lack insights from social epidemiology: contemporary patterns and future opportunities

BACKGROUND

Infectious disease epidemiologists have long recognised the importance of social variables as drivers of epidemics and disease risk, yet few apply analytic approaches from social epidemiology. We quantified and evaluated the extent to which recent infectious disease research is employing the perspectives and methods of social epidemiology by replicating the methodology used by Cohen et al in a 2007 study.

METHODS

2 search strategies were used to identify and review articles published from 1 January 2005 to 31 December 2013. First, we performed a keyword search of 'social epidemiology' in the title/abstract/text of published studies identified in PubMed, PsychInfo and ISI Web of Science, and classified each study as pertaining to infectious, non-infectious or other outcomes. A second PubMed search identified articles that were cross-referenced under non-infectious or infectious, and search terms relating to social variables. The abstracts of all articles were read, classified and examined to identify patterns over time.

RESULTS

Findings suggest that infectious disease research publications that explicitly or implicitly incorporate social epidemiological approaches have stagnated in recent years. While the number of publications that were explicitly self-classified as 'social epidemiology' has risen, the proportion that investigated infectious disease outcomes has declined. Furthermore, infectious diseases accounted for the smallest proportion of articles that were cross-referenced with Medical Subject Headings (MeSH) terms related to social factors, and most of these involved sexually transmitted diseases.

CONCLUSIONS

The current landscape of infectious disease epidemiology could benefit from new approaches to understanding how the social and biophysical environment sustains transmission and exacerbates disparities. The framework of social epidemiology provides infectious disease researchers with such a perspective and research opportunity.

Sociocultural and economic dimensions of Rift Valley fever

Health researchers have advocated for a cross-disciplinary approach to the study and prevention of infectious zoonotic diseases, such as Rift Valley Fever. It is believed that this approach can help bring out the social determinants and effects of the zoonotic diseases for the design of appropriate interventions and public health policy. A comprehensive literature review using a systematic search strategy was undertaken to explore the sociocultural and economic factors that influence the transmission and spread of Rift Valley Fever. Although the findings reveal a paucity of social research on Rift Valley Fever, they suggest that livestock sacrificial rituals, food preparation and consumption practices, gender roles, and inadequate resource base for public institutions are the key factors that influence the transmission. It is concluded that there is need for cross-disciplinary studies to increase the understanding of Rift Valley Fever and facilitate appropriate and timely response and mitigation measures.

Eco-social determinants of Schistosoma japonicum infection supported by multi-level modelling in Eryuan county, People's Republic of China

Schistosomiasis remains of considerable public health concern in many tropical and subtropical regions of the world, including the People's Republic of China (P.R. China). The effectiveness of schistosomiasis control interventions are, among other factors, governed by the social-ecological context. However, eco-social determinants of schistosomiasis are poorly understood, particularly at the household or village levels. In the current study, residents in 26 villages of Eryuan county, Yunnan province, P.R. China, were screened for Schistosoma japonicum infection with a serological assay that was followed by stool examination for sero-positive individuals. Bayesian multilevel models with spatial random effects were employed to profile the S. japonicum infection risk based on known transmission sites of S. japonicum that are scattered across individual land parcels in this part of the country. The key risk factors identified with this approach were the absence of a sanitary stall house for livestock and presence of living and infected intermediate host snails in close proximity. We conclude that a spatially explicit Bayesian multilevel approach can deepen our understanding of eco-social determinants that govern schistosomiasis transmission at a small geographical scale.

Forecasting high-priority infectious disease surveillance regions: a socioeconomic model

BACKGROUND

Few researchers have assessed the relationships between socioeconomic inequality and infectious disease outbreaks at the population level globally. We use a socioeconomic model to forecast national annual rates of infectious disease outbreaks.

METHODS

We constructed a multivariate mixed-effects Poisson model of the number of times a given country was the origin of an outbreak in a given year. The dataset included 389 outbreaks of international concern reported in the World Health Organization's Disease Outbreak News from 1996 to 2008. The initial full model included 9 socioeconomic variables related to education, poverty, population health, urbanization, health infrastructure, gender equality, communication, transportation, and democracy, and 1 composite index. Population, latitude, and elevation were included as potential confounders. The initial model was pared down to a final model by a backwards elimination procedure. The dependent and independent variables were lagged by 2 years to allow for forecasting future rates.

RESULTS

Among the socioeconomic variables tested, the final model included child measles immunization rate and telephone line density. The Democratic Republic of Congo, China, and Brazil were predicted to be at the highest risk for outbreaks in 2010, and Colombia and Indonesia were predicted to have the highest percentage of increase in their risk compared to their average over 1996-2008.

CONCLUSIONS

Understanding socioeconomic factors could help improve the understanding of outbreak risk. The inclusion of the measles immunization variable suggests that there is a fundamental basis in ensuring adequate public health capacity. Increased vigilance and expanding public health capacity should be prioritized in the projected high-risk regions.

Social connectedness and disease transmission: social organization, cohesion, village context, and infection risk in rural Ecuador

Social networks are typically seen as conduits for the spread of disease and disease risk factors. However, social relationships also reduce the incidence of chronic disease and potentially infectious diseases. Seldom are these opposing effects considered simultaneously. We have shown how and why diarrheal disease spreads more slowly to and in rural Ecuadorian villages that are more remote from the area's population center. Reduced contact with outside individuals partially accounts for remote villages' relatively lower prevalence of diarrheal disease. But equally or more important is the greater density of social ties between individuals in remote communities, which facilitates the spread of individual and collective practices that reduce the transmission of diarrheal disease.

Social epidemiology of a large outbreak of chickenpox in the Colombian sugar cane producer region: a set theory-based analysis

There are few social epidemiologic studies on chickenpox outbreaks, although previous findings suggested the important role of social determinants. This study describes the context of a large outbreak of chickenpox in the Cauca Valley region, Colombia (2003 to 2007), with an emphasis on macro-determinants. We explored the temporal trends in chickenpox incidence in 42 municipalities to identify the places with higher occurrences. We analyzed municipal characteristics (education quality, vaccination coverage, performance of health care services, violence-related immigration, and area size of planted sugar cane) through analyses based on set theory. Edwards-Venn diagrams were used to present the main findings. The results indicated that three municipalities had higher incidences and that poor quality education was the attribute most prone to a higher incidence. Potential use of set theory for exploratory outbreak analyses is discussed. It is a tool potentially useful to contrast units when only small sample sizes are available.

Bayesian spatiotemporal analysis of socio-ecologic drivers of Ross River virus transmission in Queensland, Australia

This study aims to examine the impact of socio-ecologic factors on the transmission of Ross River virus (RRV) infection and to identify areas prone to social and ecologic-driven epidemics in Queensland, Australia. We used a Bayesian spatiotemporal conditional autoregressive model to quantify the relationship between monthly variation of RRV incidence and socio-ecologic factors and to determine spatiotemporal patterns. Our results show that the average increase in monthly RRV incidence was 2.4% (95% credible interval (CrI): 0.1-4.5%) and 2.0% (95% CrI: 1.6-2.3%) for a 1 degrees C increase in monthly average maximum temperature and a 10 mm increase in monthly average rainfall, respectively. A significant spatiotemporal variation and interactive effect between temperature and rainfall on RRV incidence were found. No association between Socio-economic Index for Areas (SEIFA) and RRV was observed. The transmission of RRV in Queensland, Australia appeared to be primarily driven by ecologic variables rather than social factors.

Climate change and highland malaria: fresh air for a hot debate

In recent decades, malaria has become established in zones at the margin of its previous distribution, especially in the highlands of East Africa. Studies in this region have sparked a heated debate over the importance of climate change in the territorial expansion of malaria, where positions range from its neglect to the reification of correlations as causes. Here, we review studies supporting and rebutting the role of climatic change as a driving force for highland invasion by malaria. We assessed the conclusions from both sides of the argument and found that evidence for the role of climate in these dynamics is robust. However, we also argue that over-emphasizing the importance of climate is misleading for setting a research agenda, even one which attempts to understand climate change impacts on emerging malaria patterns. We review alternative drivers for the emergence of this disease and highlight the problems still calling for research if the multidimensional nature of malaria is to be adequately tackled. We also contextualize highland malaria as an ongoing evolutionary process. Finally, we present Schmalhausen's law, which explains the lack of resilience in stressed systems, as a biological principle that unifies the importance of climatic and other environmental factors in driving malaria patterns across different spatio-temporal scales.

Rationale and methodological options for assessing infectious disease and related measures in social science surveys

Infectious disease is an important, but often overlooked, component of population health in high-income nations. Common, everyday infections exact significant costs, including school and work absenteeism, reduced productivity, and substantial health care expenditures. Infectious disease also shapes trajectories of biological risk and health and may be causally linked to chronic disease risk later in life. The size, diversity, and representativeness of samples typically employed in survey-based studies of health present exceptional opportunities for advancing scientific knowledge on the social and economic determinants of infectious disease in childhood and adulthood and to investigate the long-term consequences of infectious disease for well-being and attainment across multiple domains. A wide range of interview-based, anthropometric, and biomarker measurement options are currently available for assessing infectious exposures, inflammation, and immune function in nonclinical settings. These methods afford opportunities for innovative, transdisciplinary research on the causes and consequences of infectious disease across the life course that can address questions of interest to social, life, and biomedical scientists.