Climate change and infectious diseases in Europe

The Complexity of Zoonotic Filariasis Episystem and Its Consequences: A Multidisciplinary View

Vector-borne transmitted helminthic zoonosis affects the health and economy of both developing and developed countries. The concept of episystem includes the set of biological, environmental, and epidemiological elements of these diseases in defined geographic and temporal scales. Dirofilariasis caused by different species of the genus Dirofilaria is a disease affecting domestic and wild canines and felines and man, transmitted by different species of culicid mosquitoes. This complexity is increased because Dirofilaria species harbor intracellular symbiont Wolbachia bacteriae, which play a key role in the embryogenesis and development of dirofilariae and in the inflammatory pathology of the disease. In addition, the vector transmission makes the dirofilariasis susceptible to the influence of the climate and its variations. The present review addresses the analysis of dirofilariasis from the point of view of the episystem, analyzing the complex network of interactions established between biological components, climate, and factors related to human activity, as well as the different problems they pose. The progress of knowledge on human and animal dirofilariasis is largely due to the multidisciplinary approach. Nevertheless, different aspects of the disease need to continue being investigated and cooperation between countries and specialists involved should be intensified.

What is a vector?

Many important and rapidly emerging pathogens of humans, livestock and wildlife are 'vector-borne'. However, the term 'vector' has been applied to diverse agents in a broad range of epidemiological systems. In this perspective, we briefly review some common definitions, identify the strengths and weaknesses of each and consider the functional differences between vectors and other hosts from a range of ecological, evolutionary and public health perspectives. We then consider how the use of designations can afford insights into our understanding of epidemiological and evolutionary processes that are not otherwise apparent. We conclude that from a medical and veterinary perspective, a combination of the 'haematophagous arthropod' and 'mobility' definitions is most useful because it offers important insights into contact structure and control and emphasizes the opportunities for pathogen shifts among taxonomically similar species with similar feeding modes and internal environments. From a population dynamics and evolutionary perspective, we suggest that a combination of the 'micropredator' and 'sequential' definition is most appropriate because it captures the key aspects of transmission biology and fitness consequences for the pathogen and vector itself. However, we explicitly recognize that the value of a definition always depends on the research question under study.This article is part of the themed issue 'Opening the black box: re-examining the ecology and evolution of parasite transmission'.

Climate variability and infectious diseases nexus: Evidence from Sweden

Many studies on the link between climate variability and infectious diseases are based on biophysical experiments, do not account for socio-economic factors and with little focus on developed countries. This study examines the effect of climate variability and socio-economic variables on infectious diseases using data from all 21 Swedish counties. Employing static and dynamic modelling frameworks, we observe that temperature has a linear negative effect on the number of patients. The relationship between winter temperature and the number of patients is non-linear and "U" shaped in the static model. Conversely, a positive effect of precipitation on the number of patients is found, with modest heterogeneity in the effect of climate variables on the number of patients across disease classifications observed. The effect of education and number of health personnel explain the number of patients in a similar direction (negative), while population density and immigration drive up reported cases. Income explains this phenomenon non-linearly. In the dynamic setting, we found significant persistence in the number of infectious and parasitic-diseased patients, with temperature and income observed as the only significant drivers.

Association between meteorological factors and hepatitis A in Spain 2010-2014

BACKGROUND

There is growing concern of how climate change could affect public health, due to the increase number of extreme climate events. Hence, the study of the role that climate events play on the distribution of waterborne diseases, like Hepatitis A, could be key for developing new prevention approaches.

OBJECTIVE

To investigate the association between climate factors and Hepatitis A in Spain between 2010 and 2014.

METHODS

Weekly Hepatitis A cases between 2010 and 2014 were obtained from the Spanish Epidemiology Surveillance Network. Climate variables (weekly cumulative rainfall, rainy days, storm days and snow days) were obtained from National Climatic Data Center (NOAA satellite and information Service of USA). Each municipality was assigned to the nearest weather station (N=73). A Mixed-Effects Poisson regression was performed to estimate Incidence Rate Ratios (IRR), including a time lag of 2, 3 and 4weeks (most probable incubation period for Hepatitis A).

RESULTS

Rainfall higher than 90th percentile (extreme precipitation) was associated with increased number of Hepatitis A cases 2weeks (IRR=1.24 CI 95%=1.09-1.40) and 4weeks after the event (IRR=1.15 CI 95%=1.01-1.30). An extra rainy day increased the risk of Hepatitis A two weeks after (IRR=1.03 CI 95%=1.01-1.05). We found higher risk of Hepatitis A two weeks after each extra storm day (IRR=1.06 CI 95%=1.00-1.12), and lower risk with 3 and 4weeks' lag (IRR=0.93 CI 95%=0.88-0.99 for lag3; IRR=0.94 CI 95%=0.88-0.99 for lag 4).

CONCLUSIONS

There is an increased risk of Hepatitis A 2weeks after water-related climate events. Including meteorological information in surveillance systems might improve to develop early prevention strategies for waterborne diseases.

Detection of Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum in questing ticks Ixodes ricinus from the Czech Republic

The aim of the present study is to compare the prevalence of Borrelia burgdorferi sensu lato (s.l.) and Anaplasma phagocytophilum in questing ticks by using molecular methods from spring to autumn 2007. A total of 526 Ixodes ricinus ticks were collected from vegetation in three different sampling sites, representing an urban area (city park), a suburban area (village) and a natural montane habitat. The prevalence of B. burgdorferi s.l. was 17.3% (7.5% in males, 18.7% in females and 20.2% in nymphs), while 4.4% of ticks (13.1% of males, 3.7% of females and 1.6% of nymphs) tested positive for A. phagocytophilum. We found higher rates of Anaplasma infection in ticks from the urban area (8.6%) than from the suburban (0.8%) and natural (1.6%) habitats in the spring months. The prevalence of Borrelia infection in the urban park increased significantly from spring (14% in March) to autumn (50% in October). The Anaplasma positivity in the urban area in the autumn months (2.2%) was significantly lower than in the spring and summer months (9.6%). The prevalence of A. phagocytophilum was significantly higher in male ticks than in females and nymphs. For B. burgdorferi s.l., the inverse was true. We conclude that infection risks associated with the presence of Anaplasma and Borrelia in ticks in cities may be comparable to those in natural ecosystems or may be even higher. Our results indicate the need for the surveillance of tick-borne pathogens in urban areas.

Establishment of Aedes aegypti (L.) in mountainous regions in Mexico: Increasing number of population at risk of mosquito-borne disease and future climate conditions

The study was conducted in the central region of Veracruz Mexico, in the metropolitan area of Xalapa. It is a mountainous area where Aedes aegypti (L.) is not currently endemic. An entomological survey was done along an elevation gradient using the Ae. aegypti occurrences at different life cycle stages. Seven sites were sampled and a total of 24 mosquito species were recorded: 9 species were found in urban areas, 18 in non-urban areas with remnant vegetation, and 3 occurred in both environments. Ae. aegypti was found only in the urban areas, usually below 1200m a.s.l., but in this study was recorded for the first time at 1420m a.s.l. These occurrences, together with additional distribution data in the state of Veracruz were used to developed species distribution models using Maxlike software in R to identify the current projected suitable areas for the establishment of this vector and the human populations that might be affected by dengue transmission at higher elevations. Its emergence in previously unsuitable places appears to be driven by both habitat destruction and biodiversity loss associated with biotic homogenization. A border study using data from the edges of the vector's distribution might allow sensitive monitoring to detect any changes in this mosquito's distribution pattern, and any changes in the anthropic drivers or climate that could increase transmission risk.

Waterborne Diseases and Climate Change: Impact and Implications

Waterborne diseases are caused by a multitude of pathogens and associated with a significant burden in both developed and developing countries. While the assessment of the adverse impacts of climate change on human heath from infectious diseases has mainly focused on vector-borne diseases, waterborne diseases prevalence and transmission patterns are also likely to be impacted by environmental change. This chapter will outline relevant waterborne pathogens, summarise the impact of climate change on disease transmission and explore climate change adaptation options in order to reduce the increased burden of waterborne diseases.

Development of a browser application to foster research on linking climate and health datasets: Challenges and opportunities

BACKGROUND

Improved data linkages between diverse environment and health datasets have the potential to provide new insights into the health impacts of environmental exposures, including complex climate change processes. Initiatives that link and explore big data in the environment and health arenas are now being established.

OBJECTIVES

To encourage advances in this nascent field, this article documents the development of a web browser application to facilitate such future research, the challenges encountered to date, and how they were addressed.

METHODS

A 'storyboard approach' was used to aid the initial design and development of the application. The application followed a 3-tier architecture: a spatial database server for storing and querying data, server-side code for processing and running models, and client-side browser code for user interaction and for displaying data and results. The browser was validated by reproducing previously published results from a regression analysis of time-series datasets of daily mortality, air pollution and temperature in London.

RESULTS

Data visualisation and analysis options of the application are presented. The main factors that shaped the development of the browser were: accessibility, open-source software, flexibility, efficiency, user-friendliness, licensing restrictions and data confidentiality, visualisation limitations, cost-effectiveness, and sustainability.

CONCLUSIONS

Creating dedicated data and analysis resources, such as the one described here, will become an increasingly vital step in improving understanding of the complex interconnections between the environment and human health and wellbeing, whilst still ensuring appropriate confidentiality safeguards. The issues raised in this paper can inform the future development of similar tools by other researchers working in this field.

Components of Population Vulnerability and Their Relationship With Climate-Sensitive Health Threats

Climate change is increasingly being framed as risks that will impact the poorest and most vulnerable communities among us. This has led to more efforts to estimate climate change risks across populations and in the context of human health and health equity. We describe the public health dimensions of climate vulnerability-exposure, population sensitivity, and adaptive capacity-and explore how these dimensions can modify population health impacts and their distribution. An overview of health disparities associated with specific climate risks is presented, and we offer potential solutions grounded in equitable urban development and improved characterization of climate vulnerabilities.

Leishmaniasis in solid organ and hematopoietic stem cell transplant recipients

Leishmaniasis occurs in <1% of solid organ and hematopoietic stem cell transplant recipients in endemic countries in which transplants are performed. Visceral leishmaniasis (VL) makes up the bulk of reported cases. The onset generally occurs months after transplantation and the mode of acquisition is often impossible to determine, but de novo vector-borne infection and reactivation of inapparent infection are thought to be the principal means. The potential role of clinically inapparent donor infection is uncertain and screening is not currently recommended, nor is it recommended for recipients from endemic areas, some of whom may have detectable circulating protozoan nucleic acid. While transplant recipients with VL often present with the non-specific findings of fever and cytopenia, the additional presence of hepatosplenomegaly in patients from endemic areas should lead to a directed diagnostic evaluation with bone marrow examination and PCR testing of marrow and peripheral blood having a high yield. Management may often be complicated by the presence of concomitant infections. A lipid formulation of amphotericin B is the preferred treatment, especially for VL, but the relapse rate in transplant recipients is approximately 25%. PCR monitoring of blood for either secondary prophylaxis or preemptive therapy requires further study.

Projections of hepatitis A virus infection associated with flood events by 2020 and 2030 in Anhui Province, China

Assessing and responding to health risk of climate change is important because of its impact on the natural and societal ecosystems. More frequent and severe flood events will occur in China due to climate change. Given that population is projected to increase, more people will be vulnerable to flood events, which may lead to an increased incidence of HAV infection in the future. This population-based study is going to project the future health burden of HAV infection associated with flood events in Huai River Basin of China. The study area covered four cities of Anhui province in China, where flood events were frequent. Time-series adjusted Poisson regression model was developed to quantify the risks of flood events on HAV infection based on the number of daily cases during summer seasons from 2005 to 2010, controlling for other meteorological variables. Projections of HAV infection in 2020 and 2030 were estimated based on the scenarios of flood events and demographic data. Poisson regression model suggested that compared with the periods without flood events, the risks of severe flood events for HAV infection were significant (OR = 1.28, 95 % CI 1.05-1.55), while risks were not significant from moderate flood events (OR = 1.16, 95 % CI 0.72-1.87) and mild flood events (OR = 1.14, 95 % CI 0.87-1.48). Using the 2010 baseline data and the flood event scenarios (one severe flood event), increased incidence of HAV infection were estimated to be between 0.126/10⁵ and 0.127/10⁵ for 2020. Similarly, the increased HAV infection incidence for 2030 was projected to be between 0.382/10⁵ and 0.399/10⁵. Our study has, for the first time, quantified the increased incidence of HAV infection that will result from flood events in Anhui, China, in 2020 and 2030. The results have implications for public health preparation for developing public health responses to reduce HAV infection during future flood events.

Global warming and the possible globalization of vector-borne diseases: a call for increased awareness and action

Human activities such as burning of fossil fuels play a role in upsetting a previously more balanced and harmonious ecosystem. Climate change—a significant variation in the usual pattern of Earth’s average weather conditions is a product of this ecosystem imbalance, and the rise in the Earth’s average temperature (global warming) is a prominent evidence. There is a correlation between global warming and the ease of transmission of infectious diseases. Therefore, with global health in focus, we herein opine a stepping-up of research activities regarding global warming and infectious diseases globally.

The Arrival of the Northern House Mosquito Culex pipiens (Diptera: Culicidae) on Newfoundland's Avalon Peninsula

Culex pipiens L., the northern house mosquito, is the primary vector of West Nile virus to humans along the east coast of North America and thus the focus of much study. This species is an urban container-breeding mosquito whose close contact with humans and flexibility in host choice has led to its classification as a "bridge vector"; that is, it is thought to move zoonotic diseases to humans from vertebrate reservoirs. While this invasive species is now well documented in its established range, which expanded in 2001 to include Canada, the existence of populations of this species along the fringes of its range are less well known. Here we report, using morphological and genetic techniques, the existence of two locations where Cx. pipiens exists in Newfoundland in both expected and unexpected sites based on projected habitat suitability on the island.

Impact of El Niño Southern Oscillation on infectious disease hospitalization risk in the United States

Although the global climate is changing at an unprecedented rate, links between weather and infectious disease have received little attention in high income countries. The "El Niño Southern Oscillation" (ENSO) occurs irregularly and is associated with changing temperature and precipitation patterns. We studied the impact of ENSO on infectious diseases in four census regions in the United States. We evaluated infectious diseases requiring hospitalization using the US National Hospital Discharge Survey (1970-2010) and five disease groupings that may undergo epidemiological shifts with changing climate: (i) vector-borne diseases, (ii) pneumonia and influenza, (iii) enteric disease, (iv) zoonotic bacterial disease, and (v) fungal disease. ENSO exposure was based on the Multivariate ENSO Index. Distributed lag models, with adjustment for seasonal oscillation and long-term trends, were used to evaluate the impact of ENSO on disease incidence over lags of up to 12 mo. ENSO was associated more with vector-borne disease [relative risk (RR) 2.96, 95% confidence interval (CI) 1.03-8.48] and less with enteric disease (0.73, 95% CI 0.62-0.87) in the Western region; the increase in vector-borne disease was attributable to increased risk of rickettsioses and tick-borne infectious diseases. By contrast, ENSO was associated with more enteric disease in non-Western regions (RR 1.12, 95% CI 1.02-1.15). The periodic nature of ENSO may make it a useful natural experiment for evaluation of the impact of climatic shifts on infectious disease risk. The impact of ENSO suggests that warmer temperatures and extreme variation in precipitation events influence risks of vector-borne and enteric disease in the United States.

Climate-driven longitudinal trends in pasture-borne helminth infections of dairy cattle

Helminth parasites of grazing ruminants are highly prevalent globally and impact negatively on animal productivity and food security. There is a growing concern that climate change increases helminth disease frequency and intensity. In Europe, these concerns stem from case reports and theoretical life cycle models assessing the effects of climate change scenarios on helminth epidemiology. We believe this study is the first to investigate climate-driven trends in helminth infections of cattle on a cohort of randomly selected farms. One thousand, six hundred and eighty dairy farms were monitored over an 8year period for the two major helminth infections in temperate climate regions and climate-driven trends were investigated by multivariable linear mixed models. The general levels of exposure to Fasciola hepatica decreased over the study period while those to Ostertagia ostertagi increased, and this could at least be partially explained by meteorological factors (i.e. the number of rainy (precipitation >1mm) and warm days (average daily temperature >10°C) in a year). The longitudinal trends varied according to the altitude and the agricultural region of the farm. This study shows that longitudinal epidemiological data from sentinel farms combined with meteorological datasets can significantly contribute to understanding the effects of climate on infectious disease dynamics. When local environmental conditions are taken into account, the effects of climate change on disease dynamics can also be understood at more local scales. We recommend setting up a longitudinal sampling strategy across Europe in order to monitor climate-driven changes in helminth disease risk to inform adaptation strategies to promote animal health and productivity.

Observed and projected drivers of emerging infectious diseases in Europe

Emerging infectious diseases are of international concern because of the potential for, and impact of, pandemics; however, they are difficult to predict. To identify the drivers of disease emergence, we analyzed infectious disease threat events (IDTEs) detected through epidemic intelligence collected at the European Centre for Disease Prevention and Control (ECDC) between 2008 and 2013, and compared the observed results with a 2008 ECDC foresight study of projected drivers of future IDTEs in Europe. Among 10 categories of IDTEs, foodborne and waterborne IDTEs were the most common, vaccine-preventable IDTEs caused the highest number of cases, and airborne IDTEs caused the most deaths. Observed drivers for each IDTE were sorted into three main groups: globalization and environmental drivers contributed to 61% of all IDTEs, public health system drivers contributed to 21%, and social and demographic drivers to 18%. A multiple logistic regression analysis showed that four of the top five drivers for observed IDTEs were in the globalization and environment group. In the observational study, the globalization and environment group was related to all IDTE categories, but only to five of eight categories in the foresight study. Directly targeting these drivers with public health interventions may diminish the chances of IDTE occurrence from the outset.

Identification of Climatic Factors Affecting the Epidemiology of Human West Nile Virus Infections in Northern Greece

Climate can affect the geographic and seasonal patterns of vector-borne disease incidence such as West Nile Virus (WNV) infections. We explore the association between climatic factors and the occurrence of West Nile fever (WNF) or West Nile neuro-invasive disease (WNND) in humans in Northern Greece over the years 2010–2014. Time series over a period of 30 years (1979–2008) of climatic data of air temperature, relative humidity, soil temperature, volumetric soil water content, wind speed, and precipitation representing average climate were obtained utilising the ECMWF’s (European Centre for Medium-Range Weather Forecasts) Re-Analysis (ERA-Interim) system allowing for a homogeneous set of data in time and space. We analysed data of reported human cases of WNF/WNND and Culex mosquitoes in Northern Greece. Quantitative assessment resulted in identifying associations between the above climatic variables and reported human cases of WNF/WNND. A substantial fraction of the cases was linked to the upper percentiles of the distribution of air and soil temperature for the period 1979–2008 and the lower percentiles of relative humidity and soil water content. A statistically relevant relationship between the mean weekly value climatic anomalies of wind speed (negative association), relative humidity (negative association) and air temperature (positive association) over 30 years, and reported human cases of WNF/WNND during the period 2010–2014 could be shown. A negative association between the presence of WNV infected Culex mosquitoes and wind speed could be identified. The statistically significant associations could also be confirmed for the week the WNF/WNND human cases appear and when a time lag of up to three weeks was considered. Similar statistically significant associations were identified with the weekly anomalies of the maximum and minimum values of the above climatic factors. Utilising the ERA-Interim re-analysis methodology it could be shown that besides air temperature, climatic factors such as soil temperature, relative humidity, soil water content and wind speed may affect the epidemiology of WNV.

A Clinical Study of Acute Kidney Injury in Tropical Acute Febrile Illness

INTRODUCTION

Tropical Acute Febrile Illness (TAFI) is one of the most common causes of morbidity within the community. Acute Kidney Injury (AKI) due to infective and non infective causes is a major complication. Presence of AKI is a major cause of mortality among patients with TAFI.

AIM

To study the spectrum of tropical acute febrile illness; the proportion, spectrum and staging of acute kidney injury; Renal Replacement Therapy (RRT) initiation and in-hospital mortality.

MATERIALS AND METHODS

A total of 600 TAFI patients were prospectively studied at a tertiary care centre in coastal Karnataka between September 2012 and September 2014 for the aetiology of TAFI; the development and staging of AKI based on Kidney disease: Improving global outcomes (KDIGO) guidelines; the initiation of RRT and in-hospital mortality.

STATISTICAL ANALYSIS

Data analysis was done using SPSS version 17.0 with statistical significance calculated using chi-square and Fisher's exact t-test for which p-value <0.05 was considered significant.

RESULTS

The spectrum of TAFI, in decreasing order, was vivax malaria, leptospirosis, dengue fever, falciparum malaria, mixed malaria, enteric fever, scrub typhus and the most common aetiology was malaria. The proportion of AKI was 54%. The most common cause of AKI, its stages 2 and 3, RRT initiation and in-hospital mortality was leptospirosis; and AKI stage 1 was dengue fever. KDIGO AKI stage 1, 2 and 3 was seen in 46.9%, 31.2% and 21.9% of AKI patients, respectively. RRT initiation was required in 10.2% of AKI patients and in-hospital mortality was 3% among all patients. AKI, RRT initiationand in-hospital mortality were significantly associated with older age, fever duration and other presenting complaints, examination findings, renal function and other parameters, leptospirosis, dengue fever, falciparum malaria.

CONCLUSION

The aetiology in about half of TAFI patients in coastal Karnataka was malaria. More than 50% develop AKI with greater than one-fifth of them progressing to AKI stage 3 and one-tenth requiring RRT. The most common cause of AKI, AKI stage 2, 3, RRT initiation and in-hospital mortality was leptospirosis. AKI was present in almost all patients with leptospirosis. Therefore leptospirosis was the most nephrotoxic acute febrile illness in the present study population. Dengue fever was the most common cause of AKI stage 1. Vivax malaria was the third most common cause of AKI. The factors like age, presenting complaints, examination findings, renal function and other parameters, aetiology and RRT initiation may be used to predict AKI and in-hospital mortality.

Extreme precipitation events and increased risk of campylobacteriosis in Maryland, U.S.A

Consumption of contaminated poultry, raw milk and water are significant risk factors for Campylobacter infection. Previous studies also have investigated the association between weather (temperature and precipitation) and increased risk of campylobacteriosis, but limited information exists regarding the impacts of extreme heat and precipitation events on campylobacteriosis risk, and how such risk may differentially impact coastal communities. We obtained Campylobacter case data 2002-2012; n=4804) from the Maryland Foodborne Diseases Active Surveillance Network (FoodNet). We identified extreme heat and extreme precipitation events during this time (2002-2012) using location and calendar day specific thresholds (95th percentile for extreme heat and 90th percentile for extreme precipitation) that were computed based on a 30-year baseline (1960-1989). We linked these datasets using GIS and used negative binomial generalized estimating equations adjusted for demographic confounders to calculate the association between exposure to extreme events and risk of campylobacteriosis in Maryland. We observed that a one-day increase in exposure to extreme precipitation events was associated with a 3% increase in risk of campylobacteriosis in coastal areas of Maryland (Incidence Rate Ratio (IRR): 1.03, 95% confidence interval (CI): 1.01, 1.05), but such an association was not observed in noncoastal areas. Furthermore, the risk associated with extreme precipitation events was considerably higher during La Niña periods (IRR: 1.09, 95% CI: 1.05, 1.13), while there was no evidence of elevated risk during El Niño or ENSO Neutral periods. Exposure to extreme heat events was not associated with an increased risk of campylobacteriosis, except during La Niña periods (IRR: 1.04, 95% CI: 1.01, 1.08). Extreme precipitation events could result in flooding within coastal areas that may bring water contaminated with bacterial pathogens (originating from sources such as septic systems, municipal wastewater treatment plants and concentrated animal feeding operations) into close proximity with individuals, where frequency of contact may be higher.

Global Health Solidarity

For much of the 20th century, vulnerability to deprivations of health has often been defined by geographical and economic factors. Those in wealthy, usually ‘Northern’ and ‘Western’, parts of the world have benefited from infrastructures, and accidents of geography and climate, which insulate them from many serious threats to health. Conversely, poorer people are typically exposed to more threats to health, and have lesser access to the infrastructures needed to safeguard them against the worst consequences of such exposure. However, in recent years the increasingly globalized nature of the world’s economy, society and culture, combined with anthropogenic climate change and the evolution of antibiotic resistance, has begun to shift the boundaries that previously defined the categories of person threatened by many exogenous threats to health. In doing so, these factors expose both new and forgotten similarities between persons, and highlight the need for global cooperative responses to the existential threats posed by climate change and the evolution of antimicrobial resistance. In this article, we argue that these emerging health threats, in demonstrating the similarities that exist between even distant persons, provides a catalyst for global solidarity, which justifies, and provides motivation for, the establishment of solidaristic, cooperative global health infrastructures.

Gastrointestinal, influenza-like illness and dermatological complaints following exposure to floodwater: a cross-sectional survey in The Netherlands

Extreme rainfall events may cause pluvial flooding, increasing the transmission of several waterborne pathogens. However, the risk of experiencing clinically overt infections following exposure to pluvial floodwater is poorly estimated. A retrospective cross-sectional survey was performed to quantify the occurrence of self-reported gastrointestinal, influenza-like illness (ILI) and dermatological complaints, and the frequency of visits to the general practitioner (GP), during a 4-week observation period following pluvial flooding at seven locations in The Netherlands. Questionnaires were sent to 817 flooded households, 149 (17%) of which returned the questionnaire reporting information for 199 participants. Contact with floodwater was significantly associated with increased occurrence of gastrointestinal [odds ratio (OR 4·44)], ILI (OR 2·75) and dermatological (OR 6·67) complaints, and GP visits (OR 2·72). Having hand contact with floodwater was associated with gastrointestinal and dermatological complaints, whereas ILI complaints were associated with being engaged in post-flooding cleaning operations and having walked/cycled through floodwater. This study shows that floodwater-associated diseases occur in urban settings following extreme rainfall events in a high-income country. As pluvial floods are expected to escalate in the future due to global climate change, further research is warranted to determine the disease burden of pluvial flooding and to assess the effect of different interventions, including raising awareness among stakeholders.

Climate change effects on airborne pathogenic bioaerosol concentrations: a scenario analysis

The most recent IPCC report presented further scientific evidence for global climate change in the twenty-first century. Important secondary effects of climate change include those on water resource availability, agricultural yields, urban healthy living, biodiversity, ecosystems, food security, and public health. The aim of this explorative study was to determine the range of expected airborne pathogen concentrations during a single outbreak or release in a future climate compared to a historical climatic period (1981-2010). We used five climate scenarios for the periods 2016-2045 and 2036-2065 defined by the Royal Netherlands Meteorological Institute and two conversion tools to create hourly future meteorological data sets. We modelled season-averaged airborne pathogen concentrations by means of an atmospheric dispersion model and compared these data to historical (1981-2010) modelled concentrations. Our results showed that modelled concentrations were modified several percentage points on average as a result of climate change. On average, concentrations were reduced in four out of five scenarios. Wind speed and global radiation were of critical importance, which determine horizontal and vertical dilution. Modelled concentrations decreased on average, but large positive and negative hourly averaged effects were calculated (from -67 to +639 %). This explorative study shows that further research should include pathogen inactivation and more detailed probability functions on precipitation, snow, and large-scale circulation.

Quantitative analysis of burden of bacillary dysentery associated with floods in Hunan, China

BACKGROUND

Jishou and Huaihua, two cities in the west of Hunan Province, had suffered from severe floods because of long-lasting and heavy rainfall during the end of June and July 2012. However, the Disability Adjusted of Life Years (DALYs) of bacillary dysentery caused by the floods have not been examined before. The study aimed to quantify the impact of the floods on the burden of bacillary dysentery in Hunan, China.

METHODS

A unidirectional case-crossover study was firstly conducted to determine the relationship between daily cases of bacillary dysentery and the floods in Jishou and Huaihua of Hunan Province in 2012. Odds ratios (ORs) estimated by conditional logistic regression were used to quantify the risk of the floods on the disease. The years lived with disability (YLDs) of bacillary dysentery attributable to floods were then estimated based on the WHO framework to calculate potential impact fraction in the Burden of Disease study.

RESULTS

Multivariable analysis showed that floods were significantly associated with an increased risk of the number of cases of bacillary dysentery (OR=3.270, 95% CI: 1.299-8.228 in Jishou; OR=2.212, 95% CI: 1.052-4.650 in Huaihua). The strongest effect was shown with a 1-day lag in Jishou and a 4-day lag in Huaihua. Attributable YLD per 1000 of bacillary dysentery due to the floods was 0.0296 in Jishou and 0.0157 in Huaihua.

CONCLUSIONS

Our study confirms that floods have significantly increased the risks of bacillary dysentery in the study areas. In addition, a sudden and severe flooding with a shorter duration may cause more burdens of bacillary dysentery than a persistent and moderate flooding. Public health preparation and intervention programs should be taken to reduce and prevent a potential risk of bacillary dysentery epidemics after floods.

Epidemiological Implications of Host Biodiversity and Vector Biology: Key Insights from Simple Models

Models used to investigate the relationship between biodiversity change and vector-borne disease risk often do not explicitly include the vector; they instead rely on a frequency-dependent transmission function to represent vector dynamics. However, differences between classes of vector (e.g., ticks and insects) can cause discrepancies in epidemiological responses to environmental change. Using a pair of disease models (mosquito- and tick-borne), we simulated substitutive and additive biodiversity change (where noncompetent hosts replaced or were added to competent hosts, respectively), while considering different relationships between vector and host densities. We found important differences between classes of vector, including an increased likelihood of amplified disease risk under additive biodiversity change in mosquito models, driven by higher vector biting rates. We also draw attention to more general phenomena, such as a negative relationship between initial infection prevalence in vectors and likelihood of dilution, and the potential for a rise in density of infected vectors to occur simultaneously with a decline in proportion of infected hosts. This has important implications; the density of infected vectors is the most valid metric for primarily zoonotic infections, while the proportion of infected hosts is more relevant for infections where humans are a primary host.

Innocuity of a commercial live attenuated vaccine for epizootic hemorrhagic disease virus serotype 2 in late-term pregnant cows

Epizootic hemorrhagic disease (EHD) is an arthropod-borne infectious viral disease sustained by the epizootic hemorrhagic disease virus (EHDV). The only commercially available and currently used vaccines are manufactured for EHDV-2 in Japan, either live or inactivated vaccines. In this study we tested the innocuity for fetuses of the live attenuated EHDV-2 vaccine in five late-term pregnant cows. Whole blood and serum samples were collected from dams and screened for the presence of EHDV-2 RNA, infectious virus and antibodies. After calving, whole blood and serum samples collected from calves, before and after colostrum intake, were also tested for antibodies and for virus detection. In dams, neither fever nor clinical signs were observed. All of them seroconverted and a strong humoral response was detected throughout the sampling period. All blood samples tested negative for EHDV-2 except for one sample collected from a dam 11 days post-vaccination which tested positive at virus isolation at the third cell passage following two rounds of blind passages. Although they had free access to colostrum, calves tested serologically negative for EHDV-2 during the entire course of the experiment. Overall, the tested live attenuated vaccine can be safely administered to late-term pregnant cows as it was not demonstrated to cross the placental barrier. The safety of the live-attenuated vaccine is further confirmed by the emergence of Ibaraki virus in 2013 in Japan which is apparently not related to the spread of the vaccine strain currently used in Japan.

The impact of meteorology on the occurrence of waterborne outbreaks of vero cytotoxin-producing Escherichia coli (VTEC): a logistic regression approach

This study analyses the relationship between meteorological phenomena and outbreaks of waterborne-transmitted vero cytotoxin-producing Escherichia coli (VTEC) in the Republic of Ireland over an 8-year period (2005-2012). Data pertaining to the notification of waterborne VTEC outbreaks were extracted from the Computerised Infectious Disease Reporting system, which is administered through the national Health Protection Surveillance Centre as part of the Health Service Executive. Rainfall and temperature data were obtained from the national meteorological office and categorised as cumulative rainfall, heavy rainfall events in the previous 7 days, and mean temperature. Regression analysis was performed using logistic regression (LR) analysis. The LR model was significant (p < 0.001), with all independent variables: cumulative rainfall, heavy rainfall and mean temperature making a statistically significant contribution to the model. The study has found that rainfall, particularly heavy rainfall in the preceding 7 days of an outbreak, is a strong statistical indicator of a waterborne outbreak and that temperature also impacts waterborne VTEC outbreak occurrence.

Impacts of Climate and Management Variables on the Contamination of Preharvest Leafy Greens with Escherichia coli

The observed seasonality of foodborne disease suggests that climatic conditions play a role and that changes in the climate may affect the presence of pathogens. However, it is hard to determine whether this effect is direct or whether it works indirectly through other factors, such as farm management. This study aimed to identify the climate and management variables that are associated with the contamination (presence and concentration) of leafy green vegetables with E. coli. This study used data about E. coli contamination from 562 leafy green vegetables (lettuce and spinach) samples taken between 2011 and 2013 from 23 open-field farms in Belgium, Brazil, Egypt, Norway, and Spain. Mixed-effect logistic and linear regression models were used to study the statistical relationship between the dependent and independent variables. Climate variables and agricultural management practices together had a systematic influence on E. coli presence and concentration. The variables important for E. coli presence included the minimum temperature of the sampling day (odds ratio = 1.47), region, and application of inorganic fertilizer. The variables important for concentration (R(2) = 0.75) were the maximum temperature during the 3 days before sampling and the region. Temperature had a stronger influence (had a significant parameter estimate and the highest R(2)) than did management practices on E. coli presence and concentration. Region was a variable that masked many management variables, including rainwater, surface water, manure, inorganic fertilizer, and spray irrigation. Climate variables had a positive relationship with E. coli presence and concentration. Temperature, irrigation water type, fertilizer type, and irrigation method should be systematically considered in future studies of fresh produce safety.

Impact of climate change on human infectious diseases: Empirical evidence and human adaptation

Climate change refers to long-term shifts in weather conditions and patterns of extreme weather events. It may lead to changes in health threat to human beings, multiplying existing health problems. This review examines the scientific evidences on the impact of climate change on human infectious diseases. It identifies research progress and gaps on how human society may respond to, adapt to, and prepare for the related changes. Based on a survey of related publications between 1990 and 2015, the terms used for literature selection reflect three aspects--the components of infectious diseases, climate variables, and selected infectious diseases. Humans' vulnerability to the potential health impacts by climate change is evident in literature. As an active agent, human beings may control the related health effects that may be effectively controlled through adopting proactive measures, including better understanding of the climate change patterns and of the compound disease-specific health effects, and effective allocation of technologies and resources to promote healthy lifestyles and public awareness. The following adaptation measures are recommended: 1) to go beyond empirical observations of the association between climate change and infectious diseases and develop more scientific explanations, 2) to improve the prediction of spatial-temporal process of climate change and the associated shifts in infectious diseases at various spatial and temporal scales, and 3) to establish locally effective early warning systems for the health effects of predicated climate change.

Public Health Adaptation to Climate Change in Large Cities: A Global Baseline

Climate change will have significant impacts on human health, and urban populations are expected to be highly sensitive. The health risks from climate change in cities are compounded by rapid urbanization, high population density, and climate-sensitive built environments. Local governments are positioned to protect populations from climate health risks, but it is unclear whether municipalities are producing climate-adaptive policies. In this article, we develop and apply systematic methods to assess the state of public health adaptation in 401 urban areas globally with more than 1 million people, creating the first global baseline for urban public health adaptation. We find that only 10% of the sampled urban areas report any public health adaptation initiatives. The initiatives identified most frequently address risks posed by extreme weather events and involve direct changes in management or behavior rather than capacity building, research, or long-term investments in infrastructure. Based on our characterization of the current urban health adaptation landscape, we identify several gaps: limited evidence of reporting of institutional adaptation at the municipal level in urban areas in the Global South; lack of information-based adaptation initiatives; limited focus on initiatives addressing infectious disease risks; and absence of monitoring, reporting, and evaluation.

Global emergence of Alphaviruses that cause arthritis in humans

Arthropod-borne viruses (arboviruses) may cause severe emerging and re-emerging infectious diseases, which pose a significant threat to human and animal health in the world today. These infectious diseases range from mild febrile illnesses, arthritis, and encephalitis to haemorrhagic fevers. It is postulated that certain environmental factors, vector competence, and host susceptibility have a major impact on the ecology of arboviral diseases. Presently, there is a great interest in the emergence of Alphaviruses because these viruses, including Chikungunya virus, O'nyong'nyong virus, Sindbis virus, Ross River virus, and Mayaro virus, have caused outbreaks in Africa, Asia, Australia, Europe, and America. Some of these viruses are more common in the tropics, whereas others are also found in temperate regions, but the actual factors driving Alphavirus emergence and re-emergence remain unresolved. Furthermore, little is known about the transmission dynamics, pathophysiology, genetic diversity, and evolution of circulating viral strains. In addition, the clinical presentation of Alphaviruses may be similar to other diseases such as dengue, malaria, and typhoid, hence leading to misdiagnosis. However, the typical presence of arthritis may distinguish between Alphaviruses and other differential diagnoses. The absence of validated diagnostic kits for Alphaviruses makes even routine surveillance less feasible. For that purpose, this review describes the occurrence, genetic diversity, clinical characteristics, and the mechanisms involving Alphaviruses causing arthritis in humans. This information may serve as a basis for better awareness and detection of Alphavirus-caused diseases during outbreaks and in establishing appropriate prevention and control measures.

Future Challenges for Vaccinologists

Vaccination is one of the cheapest health-care interventions that have saved more lives than any other drugs or therapies. Due to successful immunization programs we rarely hear about some of the common diseases of the early twentieth century including small pox and polio. Vaccination programs have also helped to increase food production notably poultry, cattle, and milk production due to lower incidence of infectious diseases in farm animals. Though vaccination programs have eradicated several diseases and increased the quality of life there are several diseases that have no effective vaccines. Currently there are no vaccines for cancer, neurodegenerative diseases, autoimmune diseases, as well as infectious diseases like tuberculosis, AIDS, and parasitic diseases including malaria. Abuse of antibiotics has resulted in the generation of several antibiotic-resistant bacterial strains; hence there is a need to develop novel vaccines for antibiotic-resistant microorganisms. Changes in climate is another concern for vaccinologists. Climate change could lead to generation of new strains of infectious microorganisms that would require development of novel vaccines. Use of conventional vaccination strategies to develop vaccines has severe limitations; hence innovative strategies are essential in the development of novel and effective vaccines.

A positive association between cryptosporidiosis notifications and ambient temperature, Victoria, Australia, 2001-2009

Increased temperatures provide optimal conditions for pathogen survival, virulence and replication as well as increased opportunities for human-pathogen interaction. This paper examined the relationship between notifications of cryptosporidiosis and temperature in metropolitan and rural areas of Victoria, Australia between 2001 and 2009. A negative binomial regression model was used to analyse monthly average maximum and minimum temperatures, rainfall and the monthly count of cryptosporidiosis notifications. In the metropolitan area, a 1 °C increase in monthly average minimum temperature of the current month was associated with a 22% increase in cryptosporidiosis notifications (incident rate ratio (IRR) 1.22; 95% confidence interval (CI) 1.13-1.31). In the rural area, a 1 °C increase in monthly average minimum temperature, lagged by 3 months, was associated with a 9% decrease in cryptosporidiosis notifications (IRR 0.91; 95% CI 0.86-0.97). Rainfall was not associated with notifications in either area. These relationships should be considered when planning public health response to ecological risks as well as when developing policies involving climate change. Rising ambient temperature may be an early warning signal for intensifying prevention efforts, including appropriate education for pool users about cryptosporidiosis infection and management, which might become more important as temperatures are projected to increase as a result of climate change.

GIS and Remote Sensing Use in the Exploration of Lyme Disease Epidemiology

Given the relatively recent recognition of Lyme disease (LD) by CDC in 1990 as a nationally notifiable infectious condition, the rise of reported human cases every year argues for a better understanding of its geographic scope. The aim of this inquiry was to explore research conducted on spatiotemporal patterns of Lyme disease in order to identify strategies for implementing vector and reservoir-targeted interventions. The focus of this review is on the use of GIS-based methods to study populations of the reservoir hosts, vectors and humans in addition to the spatiotemporal interactions between these populations. New GIS-based studies are monitoring occurrence at the macro-level, and helping pinpoint areas of occurrence at the micro-level, where spread within populations of reservoir hosts, clusters of infected ticks and tick to human transmission may be better understood.

Recent study on canine vector-borne zoonoses in southern Slovakia - serologic survey

Over the last decade a significant spread of Canine Vector Borne Diseases has been recorded in Central Europe. The aim of the study described here, was to collect current data on the occurrence and distribution of three major canine vector-borne pathogens in the veterinary clinical practice by a newly-developed commercial ELISA test for the detection of Dirofilaria immitis antigen as well as specific circulating antibodies to Anaplasma phagocytophilum and Borrelia burgdorferi sensu lato. Circulating D. immitis antigen was detected in five of 180 investigated sera samples. Two of D. immitis seropositive dogs revealed also microfilariae of D. repens in the blood and three of them were negative for the presence of microfilariae in the Knott's test. From the practical point of view, the finding of D. immitis occult infections might influence existing knowledge about distribution of this species among dogs in Central European countries. In 11.7% of the tested dogs the presence of specific antibodies against A. phagocytophilum was confirmed. Antibodies against B. burgdorferi s.l. were detected in 2.8% of tested sera samples. Coinfection with A. phagocytophilum and B. burgdorferi s.l. was observed in two dogs from Košice district in south-eastern Slovakia. Our data point toward the presence of Canine Vector Borne Diseases in the studied area. Therefore, veterinarians should include these diseases in their differential diagnosis and higher awareness should be focused also on prophylactic measures to prevent the pathogens transmission by arthropod vectors.

Larval and adult environmental temperatures influence the adult reproductive traits of Anopheles gambiae s.s

Background

Anopheles mosquito life-history parameters and population dynamics strongly influence malaria transmission, and environmental factors, particularly temperature, strongly affect these parameters. There are currently some studies on how temperature affects Anopheles gambiae s.s. survival but very few exist examining other life-history traits. We investigate here the effect of temperature on population dynamics parameters.

Methods

Anopheles gambiae s.s. immatures were reared individually at 23 ± 1 °C, 27 ± 1 °C, 31 ± 1 °C, and 35 ± 1 °C, and adults were held at their larval temperature or at one of the other temperatures. Larvae were checked every 24 h for development to the next stage and measured for size; wing length was measured as a proxy for adult size. Females were blood fed three times, and the number of females feeding and laying eggs was counted. The numbers of eggs and percentage of eggs hatched were recorded.

Results

Increasing temperatures during the larval stages resulted in significantly smaller larvae (p = 0.005) and smaller adults (p < 0.001). Adult temperature had no effect on the time to egg laying, and the larval temperature of adults only affected the incubation period of the first egg batch. Temperature influenced the time to hatching of eggs, as well as the time to development at every stage. The number of eggs laid was highest when adults were kept at 27 °C, and lowest at 31 °C, and higher adult temperatures decreased the proportion of eggs hatching after the second and third blood meal. Higher adult temperatures significantly decreased the probability of blood feeding, but the larval temperature of adults had no influence on the probability of taking a blood meal. Differences were observed between the first, second, and third blood meal in the times to egg laying and hatching, number of eggs laid, and probabilities of feeding and laying eggs.

Conclusions

Our study shows that environmental temperature during the larval stages as well as during the adult stages affects Anopheles life-history parameters. Data on how temperature and other climatic factors affect vector life-history parameters are necessary to parameterise more reliably models predicting how global warming may influence malaria transmission.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-015-1053-5) contains supplementary material, which is available to authorized users.

Epidemiology and ecology of tularemia in Sweden, 1984-2012

Geographic distribution of cases was correlated with the locations of lakes and rivers.

The zoonotic disease tularemia is endemic in large areas of the Northern Hemisphere, but research is lacking on patterns of spatial distribution and connections with ecologic factors. To describe the spatial epidemiology of and identify ecologic risk factors for tularemia incidence in Sweden, we analyzed surveillance data collected over 29 years (1984–2012). A total of 4,830 cases were notified, of which 3,524 met all study inclusion criteria. From the first to the second half of the study period, mean incidence increased 10-fold, from 0.26/100,000 persons during 1984–1998 to 2.47/100,000 persons during 1999–2012 (p<0.001). The incidence of tularemia was higher than expected in the boreal and alpine ecologic regions (p<0.001), and incidence was positively correlated with the presence of lakes and rivers (p<0.001). These results provide a comprehensive epidemiologic description of tularemia in Sweden and illustrate that incidence is higher in locations near lakes and rivers.

In situ adaptive response to climate and habitat quality variation: spatial and temporal variation in European badger (Meles meles) body weight

Variation in climatic and habitat conditions can affect populations through a variety of mechanisms, and these relationships can act at different temporal and spatial scales. Using post-mortem badger body weight records from 15 878 individuals captured across the Republic of Ireland (7224 setts across ca. 15 000 km(2) ; 2009-2012), we employed a hierarchical multilevel mixed model to evaluate the effects of climate (rainfall and temperature) and habitat quality (landscape suitability), while controlling for local abundance (unique badgers caught/sett/year). Body weight was affected strongly by temperature across a number of temporal scales (preceding month or season), with badgers being heavier if preceding temperatures (particularly during winter/spring) were warmer than the long-term seasonal mean. There was less support for rainfall across different temporal scales, although badgers did exhibit heavier weights when greater rainfall occurred one or 2 months prior to capture. Badgers were also heavier in areas with higher landscape habitat quality, modulated by the number of individuals captured per sett, consistent with density-dependent effects reducing weights. Overall, the mean badger body weight of culled individuals rose during the study period (2009-2012), more so for males than for females. With predicted increases in temperature, and rainfall, augmented by ongoing agricultural land conversion in this region, we project heavier individual badger body weights in the future. Increased body weight has been associated with higher fecundity, recruitment and survival rates in badgers, due to improved food availability and energetic budgets. We thus predict that climate change could increase the badger population across the Republic of Ireland. Nevertheless, we emphasize that, locally, populations could still be vulnerable to extreme weather variability coupled with detrimental agricultural practice, including population management.

Climate Change and Infectious Disease Risk in Western Europe: A Survey of Dutch Expert Opinion on Adaptation Responses and Actors

There is growing evidence of climate change affecting infectious disease risk in Western Europe. The call for effective adaptation to this challenge becomes increasingly stronger. This paper presents the results of a survey exploring Dutch expert perspectives on adaptation responses to climate change impacts on infectious disease risk in Western Europe. Additionally, the survey explores the expert sample's prioritization of mitigation and adaptation, and expert views on the willingness and capacity of relevant actors to respond to climate change. An integrated view on the causation of infectious disease risk is employed, including multiple (climatic and non-climatic) factors. The results show that the experts consider some adaptation responses as relatively more cost-effective, like fostering interagency and community partnerships, or beneficial to health, such as outbreak investigation and response. Expert opinions converge and diverge for different adaptation responses. Regarding the prioritization of mitigation and adaptation responses expert perspectives converge towards a 50/50 budgetary allocation. The experts consider the national government/health authority as the most capable actor to respond to climate change-induced infectious disease risk. Divergence and consensus among expert opinions can influence adaptation policy processes. Further research is necessary to uncover prevailing expert perspectives and their roots, and compare these.

Spatial and temporal variation in the association between temperature and salmonellosis in NZ

OBJECTIVE

Modelling the relationship between weather, climate and infectious diseases can help identify high-risk periods and provide understanding of the determinants of longer-term trends. We provide a detailed examination of the non-linear and delayed association between temperature and salmonellosis in three New Zealand cities (Auckland, Wellington and Christchurch).

METHODS

Salmonella notifications were geocoded to the city of residence for the reported case. City-specific associations between weekly maximum temperature and the onset date for reported salmonella infections (1997-2007) were modelled using non-linear distributed lag models, while controlling for season and long-term trends.

RESULTS

Relatively high temperatures were positively associated with infection risk in Auckland (n=3,073) and Christchurch (n=880), although the former showed evidence of a more immediate relationship with exposure to high temperatures. There was no significant association between temperature and salmonellosis risk in Wellington.

CONCLUSIONS

Projected increases in temperature with climate change may have localised health impacts, suggesting that preventative measures will need to be region-specific. This evidence contributes to the increasing concern over the public health impacts of climate change.

Climate change and adaptation of the health sector: The case of infectious diseases

Infectious diseases form a group of health problems highly susceptible to the influences of climate. Adaptation to protect human population health from the changes in infectious disease epidemiology expected to occur as a consequence of climate change involve actions in the health systems as well as in other non-health sectors. In the health sector strategies such as enhanced and targeted epidemiological and entomological surveillance and the development of epidemic early warning systems informed by climate scenarios are needed. Measures in other sectors such as meteorology, civil defense and environmental sanitation will also contribute to a reduction in the risk of infection under climate change.

Effects of climate change on Salmonella infections

BACKGROUND

Climate change and global warming have been reported to increase spread of foodborne pathogens. To understand these effects on Salmonella infections, modeling approaches such as regression analysis and neural network (NN) were used.

METHODS

Monthly data for Salmonella outbreaks in Mississippi (MS), Tennessee (TN), and Alabama (AL) were analyzed from 2002 to 2011 using analysis of variance and time series analysis. Meteorological data were collected and the correlation with salmonellosis was examined using regression analysis and NN.

RESULTS

A seasonal trend in Salmonella infections was observed (p<0.001). Strong positive correlation was found between high temperature and Salmonella infections in MS and for the combined states (MS, TN, AL) models (R(2)=0.554; R(2)=0.415, respectively). NN models showed a strong effect of rise in temperature on the Salmonella outbreaks. In this study, an increase of 1°F was shown to result in four cases increase of Salmonella in MS. However, no correlation between monthly average precipitation rate and Salmonella infections was observed.

CONCLUSION

There is consistent evidence that gastrointestinal infection with bacterial pathogens is positively correlated with ambient temperature, as warmer temperatures enable more rapid replication. Warming trends in the United States and specifically in the southern states may increase rates of Salmonella infections.

Big data for health

This paper provides an overview of recent developments in big data in the context of biomedical and health informatics. It outlines the key characteristics of big data and how medical and health informatics, translational bioinformatics, sensor informatics, and imaging informatics will benefit from an integrated approach of piecing together different aspects of personalized information from a diverse range of data sources, both structured and unstructured, covering genomics, proteomics, metabolomics, as well as imaging, clinical diagnosis, and long-term continuous physiological sensing of an individual. It is expected that recent advances in big data will expand our knowledge for testing new hypotheses about disease management from diagnosis to prevention to personalized treatment. The rise of big data, however, also raises challenges in terms of privacy, security, data ownership, data stewardship, and governance. This paper discusses some of the existing activities and future opportunities related to big data for health, outlining some of the key underlying issues that need to be tackled.

Arboviral infections diagnosed in a European area colonized by Aedes albopictus (2009-2013, Catalonia, Spain)

BACKGROUND

The invasive mosquito Aedes albopictus, with proven vectorial ability to transmit European autochthonous cycles of dengue and chikungunya virus, has currently colonized every coastal department of Eastern Spain. The main objective of the study was to define the epidemiological and clinical characteristics as well as the trends of these two arboviral diseases in a European area heavily colonized by Ae. albopictus.

METHOD

A voluntarily-based, prospective and multicenter surveillance study was performed in all medical units of the North Metropolitan area of Barcelona (406,000 inhabitants, Catalonia; Spain) with diagnostic capability from 2009 to 2013. Since any possible increase in arboviral cases could be justified by changes in traveling behaviors along the study period (especially longer trips) the trend showed by these two arboviral diseases was compared with that displayed by malaria cases during the same period.

RESULTS

38 out of 52 (73.1%) suspected cases could be serologically confirmed (IgM+): dengue 34/38 (89.5%) and chikungunya 4/38 (11.5%). No autochthonous cases were identified. The overall incidence of both arboviruses was 0.19 cases/10,000 inhabitants-year (95% CI: 0.07-0.3); dengue = 0.17 cases/10,000 inhabitants-year (95% CI: 0.05-0.3), and chikungunya = 0.02 cases/10,000 inhabitants-year (95% CI: 0.001-0.03). The Incidence Relative Risk of arboviral disease between 2009 and 2013 shown a significant trend (IRR = 1.27. IC 95%: 1.01-1.59; p = 0.043) when compared with that displayed by malaria (IRR = 1.04. IC 95%: 0.924-1.192). If no unexpected circumstances concur, the arboviral disease incidence tax would equal that of malaria about 2021-2022.

CONCLUSIONS

The incidence of dengue and chikungunya is steadily increasing in the North Metropolitan area of Barcelona, a region densely colonized by Ae. albopictus, at the entire expense of imported cases (especially Visiting Friends and Relatives travelers). To date, no secondary autochthonous cases have been identified and, thus, they have not taken part in this rise.