Epidemiological Processes Research Articles

Phylodynamic Model Adequacy Using Posterior Predictive Simulations

Rapidly evolving pathogens, such as viruses and bacteria, accumulate genetic change at a similar timescale over which their epidemiological processes occur, such that, it is possible to make inferences about their infectious spread using phylogenetic time-trees. For this purpose it is necessary to choose a phylodynamic model. However, the resulting inferences are contingent on whether the model adequately describes key features of the data. Model adequacy methods allow formal rejection of a model if it cannot generate the main features of the data. We present TreeModelAdequacy, a package for the popular BEAST2 software that allows assessing the adequacy of phylodynamic models. We illustrate its utility by analyzing phylogenetic trees from two viral outbreaks of Ebola and H1N1 influenza. The main features of the Ebola data were adequately described by the coalescent exponential-growth model, whereas the H1N1 influenza data were best described by the birth–death susceptible-infected-recovered model.

Molecular evidence of the reservoir competence of water buffalo (Bubalus bubalis) for Anaplasma marginale in Cuba.

Water buffalo (Bubalus bubalis) is a potential reservoir for Anaplasma marginale in livestock ecosystems of tropical countries. However, their participation in the epidemiological process of bovine anaplasmosis in endemic areas remains unclear. In the present study, the reservoir competence of water buffalo for A. marginale was explored by focusing on the analysis of rickettsemia levels in carrier animals, and the genetic characterization of A. marginale strains from cattle and buffalo. Eight groups of cattle and water buffaloes were randomly selected from cohabiting herds in four livestock ecosystems of Cuba, together with two control groups from unrelated cattle and buffalo herds. A total of 180 adult animals (88 water buffalo and 92 cattle) were sampled. Rickettsemia in carrier animals was determined by quantitative real-time PCR. The rickettsemia (parasitemia) levels in cattle were higher than in buffaloes, however the rickettsemia in buffalo may be enough to infect R. microplus ticks. The genetic diversity of A. marginale was assessed by strain characterization and phylogenetic analysis of 27 msp1α gene sequences. The results showed genetic similarity among strains from cattle and water buffalo, suggesting the occurrence of cross-species transmission.

The Impact of Alcohol Consumption on Mortality Among Patients with Complex Cervical Trauma

Alcohol seems to be an important risk factor and a major cause of death for the patients with complex cervical trauma. The morbidity and mortality by complex cervical trauma is increasing all over the world, the most common mechanism of damage being a stab wound from violent attack, but also gunshot wounds, road traffic accidents or self-harm are noted. In addition to penetrating trauma, neck injuries can appear due to blunt trauma. We conducted a retrospective analysis on 289 deceased patients by complex cervical trauma. We aimed to focus on the relationship between alcohol blood level and cervical trauma mortality by various mechanisms. In our study, the alcohol blood level in deceased patients by complex cervical trauma is influenced by gender and socioeconomic background. Alcoholism was correlated with autolithic mechanism in 56.3% of the cases and aggression in 46.7%. Complex cervical trauma represents a pathology with multifaceted epidemiological, etiopathogenic and pathophysiological processes. Our results could bring new epidemiological data in order to improve public health policies, and from there to decrease alcohol related mortality on cervical trauma.

HmmIBD: software to infer pairwise identity by descent between haploid genotypes

BackgroundA number of recent malaria studies have used identity by descent (IBD) to study epidemiological processes relevant to malaria control. In this paper, a software package, hmmIBD, is introduced for estimating pairwise IBD between haploid genomes, such as those of the malaria parasite, sampled from one or two populations. Source code is freely available.MethodsThe performance of hmmIBD was verified using simulated data and benchmarked against an existing method for detecting IBD within populations. Code for all tests is freely available. The utility of hmmIBD for detecting IBD across populations was demonstrated using Plasmodium falciparum data from Cambodia and Ghana.ResultsAlongside an existing method, hmmIBD was highly accurate, sensitive and specific. It is fast, requiring only 70 s on average to analyse 50 whole genome sequences on a laptop computer, and scales linearly in the number of pairwise comparisons. Treatment of different populations under hmmIBD improves detection of IBD across populations.ConclusionFast and accurate software for detecting IBD in malaria parasite genetic data sampled from one or two populations is presented. The latter will likely be a useful feature for malaria elimination efforts, since it could facilitate identification of imported malaria cases. Software is robust to possible misspecification of the genotyping error and the recombination rate. However, exclusion of data in regions whose rates vary greatly from their genome-wide average is recommended.

Modeling epidemiological disturbances in LANDIS-II

Forest landscape simulation models (FLSMs) – often used to understand and project forest dynamics over space and time in response to environmental disturbance – have rarely included realistic epidemiological processes of plant disease transmission and impacts. Landscape epidemiological models, by contrast, frequently treat forest ecosystems as static or make simple assumptions regarding ecosystem change following disease. Here we present the Base Epidemiological Disturbance Agent (EDA) extension that allows users of the LANDIS-II FLSM to simulate forest pathogen spread and host mortality within a spatially explicit forest simulation. EDA enables users to investigate forest pathogen spread and impacts over large landscapes (> 105 ha) and long time periods. We evaluate the model extension using Phytophthora ramorum as a case study of an invasive plant pathogen causing emerging infectious disease and considerable tree mortality in California. EDA will advance the utility of LANDIS-II and forest disease modeling in general.

Особливості епідемічного процесу гепатиту а та його зв’язок із накопиченням побутових полімерних відходів у довкіллі

In this work a sanitary-hygienic assessment of the features of the epidemic process for hepatitis A disease among the population has been conducted and its connection with the accumulation of household waste in the environment has been established On the whole territory of Ukraine an unstable epidemic situation with hepatitis A disease is noted. It is connected with a change in the main factors that affect the transmission of infection. Therefore, the issue of establishing a link between the spread of hepatitis A in the environment and the processes that provide it are relevant. To this end, the epidemiological features of hepatitis A in the Ivano-Frankivsk region were studied for improving the system of preventive and anti-epidemic measures involving specialists and equipment of the SI “Ivano-Frankivsk Regional Laboratory Centre of the Ministry of Health of Ukraine”. Calculations were made according to the statistical record of morbidity (reporting form № 2 and № 40). It is established that the main way of transmission of viral hepatitis A remains water from decentralized sources. In addition, the incidence of hepatitis A is characterized by uneven distribution and predominates in mountainous areas. For the period from 2011 to 2016 there is an active involvement of working-age people in the epidemiological process, whose share on average is 73.5%. The morbidity is almost equally widespread, both among the urban population and among the rural population. The peaks of the disease coincide in time with floods, when sewage networks and wastewater treatment plants did not cope with this volume of wastewater due to their clogging with household waste, mainly polymeric packages. Therefore, the barrier role of communal treatment facilities and the sewage system, in relation to the hepatitis A virus, is insufficient and requires the improvement of the technology of water purification and preparation. It is necessary to develop infrastructure to provide centralized water supply to the population of the mountainous areas of the region, where it is hygienically and economically justified. A promising direction for further scientific research is the development and implementation at the state level of basic preventive measures aimed at optimizing social and hygienic living conditions of the population and in the fight against hepatitis A, there is a technical and technological update of: communal systems of water supply, drainage, sanitary cleaning of the territory; organization of catering and trade and the prohibition of street trade, as well as mass immunization of the most vulnerable groups of the population; control over the provision and compliance with sanitary and hygiene norms and rules; prohibition of the production, use, import and payment or free distribution of polymer packages in Ukrainian territory. Key words : hepatitis A , epidemiology , communal hygiene , polymeric waste

Inferring pathogen dynamics from temporal count data: the emergence of Xylella fastidiosa in France is probably not recent.

Summary Unravelling the ecological structure of emerging plant pathogens persisting in multi‐host systems is challenging. In such systems, observations are often heterogeneous with respect to time, space and host species, and may lead to biases of perception. The biased perception of pathogen ecology may be exacerbated by hidden fractions of the whole host population, which may act as infection reservoirs.We designed a mechanistic‐statistical approach to help understand the ecology of emerging pathogens by filtering out some biases of perception. This approach, based on SIR (Susceptible–Infected–Removed) models and a Bayesian framework, disentangles epidemiological and observational processes underlying temporal counting data.We applied our approach to French surveillance data on Xylella fastidiosa, a multi‐host pathogenic bacterium recently discovered in Corsica, France. A model selection led to two diverging scenarios: one scenario without a hidden compartment and an introduction around 2001, and the other with a hidden compartment and an introduction around 1985.Thus, Xylella fastidiosa was probably introduced into Corsica much earlier than its discovery, and its control could be arduous under the hidden compartment scenario. From a methodological perspective, our approach provides insights into the dynamics of emerging plant pathogens and, in particular, the potential existence of infection reservoirs.

Recurrent outbreaks caused by the same Salmonella enterica serovar Infantis clone in a German rehabilitation oncology clinic from 2002 to 2009

Repeated outbreaks of salmonellosis caused by Salmonella enterica serovar Infantis at a rehabilitation clinic in Germany were investigated microbiologically from August 2002 to August 2009. To identify the sources of transmission and characterize the S.enterica serovar Infantis isolates. Associated with these outbreaks, isolates from 98 patients, two kitchen staff, five food samples, four swabs of kitchen facilities, three samples of chicken faeces and one sample of sewage water were evaluated by phage typing. All S.enterica serovar Infantis isolates investigated (N=113) were related to phage type (PT) 29. Additionally, 44 of the 113 isolates were selected at random for typing by XbaI macrorestriction and pulsed-field gel electrophoresis (PFGE). Typing of the 44 isolates showed that the recurrent infections were caused by the single clone PT 29/XB27+44 (42/44, 95.5%). The most likely route of transmission was only identified in the last outbreak in 2009 within the present study. It was found to be cross-contamination in the kitchen facilities (emanating from a contaminated wooden panel), in combination with carriers among the kitchen staff. This study demonstrated important details of hospital-specific epidemiological processes, and alludes to a long-term reservoir of an epidemic clone of S.enterica serovar Infantis either in a backyard flock of poultry or in an inanimate kitchen reservoir.

Community Intervention In Elderly Population: A Fall Prevention Project

Objective: This article seeks to present a pilot project of community intervention that aims to prevent the occurrence of falls in the elderly in a community setting.
 Method: It is a prospective study in the temporal relationship, based on Health Planning, it was developed for 9 weeks in a Community Care Unit in the Northern Region of Portugal. Data collection and interventions were performed in the home of 6 of the 12 elderly being followed up at home by the nursing team. Elderly institutionalized and totally dependent were excluded. For the collection of data, an evaluation protocol was filled out using the Morse scale, validated for the Portuguese population, to assess the risk of falls. 
 Results: Of the elderly who underwent nursing interventions, 50% presented a high risk of falls. Epidemiological indicators show that the incidence rate of falls was 0% and the prevalence rate of falls, in the last year was, 37.5%. 
 Conclusion: The data collected was used for the production of epidemiological indicators, structure, process, and results. It is suggested to continue the project for one year, covering a larger sample and subsequent evaluation, and the creation of indicators for informal care providers.

Theoretical Background and Real Results: A Data Review on Vaccine Prevention of Pneumococcal Infection in the World

The article presents the review aimed at summarizing the opinions on the epidemiology of pneumococcal infection and the most effective measures for its prevention. The review combines the results of the trials conducted by Russian and international groups who analysed vaccine prophylaxis of pneumococcal infection. In the previous review on the most important indicators of the effectiveness of vaccination against pneumococcal infection, the main approaches to the assessment of the effectiveness of vaccination against pneumococcal infection were identified, and the academic data on the global experience of pneumococcal conjugate vaccination was systematized. This review results in cumulation of evidence for the efficacy and impact of pneumococcal conjugate vaccines on the key «end points» of the epidemiological process of pneumococcal infection.

Modelling the large-scale yellow fever outbreak in Luanda, Angola, and the impact of vaccination.

BackgroundYellow fever (YF), transmitted via bites of infected mosquitoes, is a life-threatening viral disease endemic to tropical and subtropical regions of Africa and South America. YF has largely been controlled by widespread national vaccination campaigns. Nevertheless, between December 2015 and August 2016, YF resurged in Angola, quickly spread and became the largest YF outbreak for the last 30 years. Recently, YF resurged again in Brazil (December 2016). Thus, there is an urgent need to gain better understanding of the transmission pattern of YF.ModelThe present study provides a refined mathematical model, combined with modern likelihood-based statistical inference techniques, to assess and reconstruct important epidemiological processes underlying Angola’s YF outbreak. This includes the outbreak’s attack rate, the reproduction number (), the role of the mosquito vector, the influence of climatic factors, and the unusual but noticeable appearance of two-waves in the YF outbreak. The model explores actual and hypothetical vaccination strategies, and the impacts of possible human reactive behaviors (e.g., response to media precautions).FindingsWhile there were 73 deaths reported over the study period, the model indicates that the vaccination campaign saved 5.1-fold more people from death and saved from illness 5.6-fold of the observed 941 cases. Delaying the availability of the vaccines further would have greatly worsened the epidemic in terms of increased cases and deaths. The analysis estimated a mean and an attack rate of 0.09-0.15% (proportion of population infected) over the whole period from December 2015 to August 2016. Our estimated lower and upper bounds of are in line with previous studies. Unusually, oscillated in a manner that was “delayed” with the reported deaths. High recent number of deaths were associated (followed) with periods of relatively low disease transmission and low , and vice-versa. The time-series of Luanda’s YF cases suggest the outbreak occurred in two waves, a feature that would have become far more prominent had there been no mass vaccination. The waves could possibly be due to protective reactive behavioral changes of the population affecting the mosquito population. The second wave could well be an outcome of the March-April rainfall patterns in the 2016 El Niño year by creating ideal conditions for the breeding of the mosquito vectors. The modelling framework is a powerful tool for studying future YF epidemic outbreaks, and provides a basis for future vaccination campaign evaluations.

When increasing population density can promote the evolution of metabolic cooperation.

Microbial cooperation drives ecological and epidemiological processes and is affected by the ecology and demography of populations. Population density influences the selection for cooperation, with spatial structure and the type of social dilemma, namely public-goods production or self-restraint, shaping the outcome. While existing theories predict that in spatially structured environments increasing population density can select either for or against cooperation, experimental studies with both public-goods production and self-restraint systems have only ever shown that increasing population density favours cheats. We suggest that the disparity between theory and empirical studies results from experimental procedures not capturing environmental conditions predicted by existing theories to influence the outcome. Our study resolves this issue and provides the first experimental evidence that high population density can favour cooperation in spatially structured environments for both self-restraint and public-goods production systems. Moreover, using a multi-trait mathematical model supported by laboratory experiments we extend this result to systems where the self-restraint and public-goods social dilemmas interact. We thus provide a systematic understanding of how the strength of interaction between the two social dilemmas and the degree of spatial structure within an environment affect selection for cooperation. These findings help to close the current gap between theory and experiments.

Technique of transformation of an epidemiological stochastic process

Technique of transformation of an epidemiological stochastic process

МНОЖЕСТВЕННАЯ ЛЕКАРСТВЕННАЯ УСТОЙЧИВОСТЬ У ВПЕРВЫЕ ВЫЯВЛЕННЫХ БОЛЬНЫХ ТУБЕРКУЛЁЗОМ В РЕСПУБЛИКЕ САХА (ЯКУТИЯ)

Epidemiological process of tuberculosis (TB) in the Sakha Republic (Yakutia) has been characterized by growing incidence of M. tuberculosis (MTB) multidrug-resistance (MDR). This study aimed to explore the incidence of primary MDR in patients with pulmonary TBin Yakutia from 2011 to 2016. Rates of primary MDR (including extensively drug resistant (XDR) cases) incidence were analyzed in new patients with sputum- and/or culture-positive pulmonary TB for Yakutia, Yakutsk, rural regions of Yakutia, and 5 major territorial zones of Yakutia, through theyears 2011 to 2016. We observed an increase from 23 % to 25 % in the proportion of pulmonary TB among primary MDR cases in Yakutia, for the study period. In 2016, this proportion was 1.1 times higher than in Russia (23.4 %), but lower than in the Far East Federal District (25.7 %). In Yakutsk, the same proportion has increased by half (from 24.2 to 35.4 %); in rural regions, on the contrary, it decreased by half (from 21.9 to 14.9 %). Primary MDR percentages among new cases of pulmonary TB decreased in South Yakutia and West Yakutia zones (by factors of 6.7 and 1.6, respectively); same proportions in the Arctic and Central Yakutia zones changed insignificantly. In East Yakutia zone, no case of primary MdR was detected in 2016. XDR cases among new pulmonary TB cases were solitary in 2011, detected only in Yakutsk. During the study period, incidence of XDR among new pulmonary TB cases increased from 0.5 % to 1.7 %, and cases with primary XDR were detected in Yakutsk and Arctic zone.

Genome-wide evolutionary dynamics of influenza B viruses on a global scale.

The global-scale epidemiology and genome-wide evolutionary dynamics of influenza B remain poorly understood compared with influenza A viruses. We compiled a spatio-temporally comprehensive dataset of influenza B viruses, comprising over 2,500 genomes sampled worldwide between 1987 and 2015, including 382 newly-sequenced genomes that fill substantial gaps in previous molecular surveillance studies. Our contributed data increase the number of available influenza B virus genomes in Europe, Africa and Central Asia, improving the global context to study influenza B viruses. We reveal Yamagata-lineage diversity results from co-circulation of two antigenically-distinct groups that also segregate genetically across the entire genome, without evidence of intra-lineage reassortment. In contrast, Victoria-lineage diversity stems from geographic segregation of different genetic clades, with variability in the degree of geographic spread among clades. Differences between the lineages are reflected in their antigenic dynamics, as Yamagata-lineage viruses show alternating dominance between antigenic groups, while Victoria-lineage viruses show antigenic drift of a single lineage. Structural mapping of amino acid substitutions on trunk branches of influenza B gene phylogenies further supports these antigenic differences and highlights two potential mechanisms of adaptation for polymerase activity. Our study provides new insights into the epidemiological and molecular processes shaping influenza B virus evolution globally.

Genotypic and Phylogenetic Insights on Prevention of the Spread of HIV-1 and Drug Resistance in "Real-World" Settings.

HIV continues to spread among vulnerable heterosexual (HET), Men-having-Sex with Men (MSM) and intravenous drug user (IDU) populations, influenced by a complex array of biological, behavioral and societal factors. Phylogenetics analyses of large sequence datasets from national drug resistance testing programs reveal the evolutionary interrelationships of viral strains implicated in the dynamic spread of HIV in different regional settings. Viral phylogenetics can be combined with demographic and behavioral information to gain insights on epidemiological processes shaping transmission networks at the population-level. Drug resistance testing programs also reveal emergent mutational pathways leading to resistance to the 23 antiretroviral drugs used in HIV-1 management in low-, middle- and high-income settings. This article describes how genotypic and phylogenetic information from Quebec and elsewhere provide critical information on HIV transmission and resistance, Cumulative findings can be used to optimize public health strategies to tackle the challenges of HIV in “real-world” settings.

Prior exposure to non-pathogenic calicivirus RCV-A1 reduces both infection rate and mortality from rabbit haemorrhagic disease in a population of wild rabbits in Australia.

Mortality caused by rabbit haemorrhagic disease virus (RHDV) in wild rabbits is reduced in parts of Australia where the related, non-pathogenic calicivirus RCV-A1 is endemic. Laboratory experiments previously showed that prior infection with RCV-A1 enabled rabbits to better withstand subsequent infection with highly virulent RHDV, and this was assumed to explain higher survival. Here, we analyse serological data from the field suggesting that reduced mortality rates among wild rabbits may also result from rabbits previously infected with RCV-A1 having a reduced likelihood of RHDV infection. We discuss the possible mechanisms underlying this finding and its implications. The methods we describe for analysing field data gave far greater insights into epidemiological processes and virus interactions than gained from reporting basic seroprevalence rates alone.

Twenty-Five Years of the Binary Power Law for Characterizing Heterogeneity of Disease Incidence.

Spatial pattern, an important epidemiological property of plant diseases, can be quantified at different scales using a range of methods. The spatial heterogeneity (or overdispersion) of disease incidence among sampling units is an especially important measure of small-scale pattern. As an alternative to Taylor's power law for the heterogeneity of counts with no upper bound, the binary power law (BPL) was proposed in 1992 as a model to represent the heterogeneity of disease incidence (number of plant units diseased out of n observed in each sampling unit, or the proportion diseased in each sampling unit). With the BPL, the log of the observed variance is a linear function of the log of the variance for a binomial (i.e., random) distribution. Over the last quarter century, the BPL has contributed to both theory and multiple applications in the study of heterogeneity of disease incidence. In this article, we discuss properties of the BPL and use it to develop a general conceptualization of the dynamics of spatial heterogeneity in epidemics; review the use of the BPL in empirical and theoretical studies; present a synthesis of parameter estimates from over 200 published BPL analyses from a wide range of diseases and crops; discuss model fitting methods, and applications in sampling, data analysis, and prediction; and make recommendations on reporting results to improve interpretation. In a review of the literature, the BPL provided a very good fit to heterogeneity data in most publications. Eighty percent of estimated slope (b) values from field studies were between 1.06 and 1.51, with b positively correlated with the BPL intercept parameter. Stochastic simulations show that the BPL is generally consistent with spatiotemporal epidemiological processes and holds whenever there is a positive correlation of disease status of individuals composing sampling units.

Estimating the fitness cost and benefit of cefixime resistance in Neisseria gonorrhoeae to inform prescription policy: A modelling study.

BackgroundGonorrhoea is one of the most common bacterial sexually transmitted infections in England. Over 41,000 cases were recorded in 2015, more than half of which occurred in men who have sex with men (MSM). As the bacterium has developed resistance to each first-line antibiotic in turn, we need an improved understanding of fitness benefits and costs of antibiotic resistance to inform control policy and planning. Cefixime was recommended as a single-dose treatment for gonorrhoea from 2005 to 2010, during which time resistance increased, and subsequently declined.Methods and findingsWe developed a stochastic compartmental model representing the natural history and transmission of cefixime-sensitive and cefixime-resistant strains of Neisseria gonorrhoeae in MSM in England, which was applied to data on diagnoses and prescriptions between 2008 and 2015. We estimated that asymptomatic carriers play a crucial role in overall transmission dynamics, with 37% (95% credible interval CrI 24%–52%) of infections remaining asymptomatic and untreated, accounting for 89% (95% CrI 82%–93%) of onward transmission. The fitness cost of cefixime resistance in the absence of cefixime usage was estimated to be such that the number of secondary infections caused by resistant strains is only about half as much as for the susceptible strains, which is insufficient to maintain persistence. However, we estimated that treatment of cefixime-resistant strains with cefixime was unsuccessful in 83% (95% CrI 53%–99%) of cases, representing a fitness benefit of resistance. This benefit was large enough to counterbalance the fitness cost when 31% (95% CrI 26%–36%) of cases were treated with cefixime, and when more than 55% (95% CrI 44%–66%) of cases were treated with cefixime, the resistant strain had a net fitness advantage over the susceptible strain. Limitations include sparse data leading to large intervals on key model parameters and necessary assumptions in the modelling of a complex epidemiological process.ConclusionsOur study provides, to our knowledge, the first estimates of the fitness cost and benefit associated with resistance of the gonococcus to a clinically relevant antibiotic. Our findings have important implications for antibiotic stewardship and public health policies and, in particular, suggest that a previously abandoned antibiotic could be used again to treat a minority of gonorrhoea cases without raising resistance levels.

Wildlife disease ecology from the individual to the population: Insights from a long-term study of a naturally infected European badger population.

Long-term individual-based datasets on host-pathogen systems are a rare and valuable resource for understanding the infectious disease dynamics in wildlife. A study of European badgers (Meles meles) naturally infected with bovine tuberculosis (bTB) at Woodchester Park in Gloucestershire (UK) has produced a unique dataset, facilitating investigation of a diverse range of epidemiological and ecological questions with implications for disease management. Since the 1970s, this badger population has been monitored with a systematic mark-recapture regime yielding a dataset of >15,000 captures of >3,000 individuals, providing detailed individual life-history, morphometric, genetic, reproductive and disease data. The annual prevalence of bTB in the Woodchester Park badger population exhibits no straightforward relationship with population density, and both the incidence and prevalence of Mycobacterium bovis show marked variation in space. The study has revealed phenotypic traits that are critical for understanding the social structure of badger populations along with mechanisms vital for understanding disease spread at different spatial resolutions. Woodchester-based studies have provided key insights into how host ecology can influence infection at different spatial and temporal scales. Specifically, it has revealed heterogeneity in epidemiological parameters; intrinsic and extrinsic factors affecting population dynamics; provided insights into senescence and individual life histories; and revealed consistent individual variation in foraging patterns, refuge use and social interactions. An improved understanding of ecological and epidemiological processes is imperative for effective disease management. Woodchester Park research has provided information of direct relevance to bTB management, and a better appreciation of the role of individual heterogeneity in disease transmission can contribute further in this regard. The Woodchester Park study system now offers a rare opportunity to seek a dynamic understanding of how individual-, group- and population-level processes interact. The wealth of existing data makes it possible to take a more integrative approach to examining how the consequences of individual heterogeneity scale to determine population-level pathogen dynamics and help advance our understanding of the ecological drivers of host-pathogen systems.