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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2006.03.019 Byline: Kian Febrer, Tracey A. Jones, Christl A. Donnelly, Marian Stamp Dawkins Abstract: We investigated the response of commercially farmed broiler (meat) chickens to their social environment at five stocking densities, using spatial distribution and behaviour. We used a computer model in which a 'social aversion/attraction' parameter was set at different values to give simulations in which the chickens were averse, indifferent or positively attracted to each other. We examined the spatial distribution of real chickens that were neither feeding nor drinking, using video records taken within commercial houses, to see which setting of the model best fitted the observed data. At all stocking densities, chickens were more clustered than indifferent (randomly distributed) chickens, and their distribution best fitted a social attraction model in which simulated birds rejected a potential position if their distance from other birds was too great. The parameter setting that best fitted the observed data was a model in which simulated chickens had a high probability of rejecting a position if the nearest chicken was more than an estimated 75cm away: they were socially attracted rather than socially averse. This result suggests that, even at high commercial stocking densities, real broiler chickens may find the close proximity of other birds more attractive than aversive. Except for jostling and number of strides per walking bout, behaviour did not change across the stocking densities studied, nor, except for gait, did the most obvious measures of bird health (mortality, culls, leg health). Author Affiliation: (a) Department of Zoology, University of Oxford, Oxford, UK (a ) Department of Infectious Disease Epidemiology, Imperial College, London, UK Article History: Received 19 July 2005; Revised 19 October 2005; Accepted 20 March 2006 Article Note: (miscellaneous) MS. number: 8613

• We estimate vaccination impact in the 2017/19 hepatitis A virus outbreak in Louisville. • Critical vaccination threshold among persons who experience homelessness or who use drugs was 77% assuming 90% vaccine efficacy. • Vaccination during the outbreak accounted for at least US$490000 in cost savings. • Earlier and faster vaccination would have led to greater impact. Between September 2017 and June 2019, an outbreak of hepatitis A virus (HAV) occurred in Louisville, Kentucky, resulting in 501 cases and 6 deaths, predominantly among persons who experience homelessness or who use drugs (PEH/PWUD). The critical vaccination threshold (V c) required to achieve herd immunity in this population is unknown. We investigated V c and vaccination impact using epidemic modeling. To determine which population subgroups had high infection risks, we employed a technique based on comparing the proportion of cases arising before and after the epidemic peak, across subgroups. We also developed a dynamic deterministic model of HAV transmission among PEH/PWUD to estimate the basic reproduction number (R 0), herd immunity threshold, V c and the effect of timing of the vaccination intervention on epidemic and economic outcomes. Of the 501 confirmed or probable cases, 385 (76.8%) were among PEH/PWUD. Among PEH/PWUD and within the general population, homelessness was a significant risk factor for infection in the initial stages of the outbreak (odds ratios for homeless versus not homeless: 2.62; 95% confidence interval (CI): 1.62–4.25 for PEH/PWUD and 2.39; 95% CI: 1.51–3.78 for all detected cases). Our estimate for R 0 ranges between 2.85 and 3.54, corresponding to an estimate of 69% (95% CI: 65–72) for herd immunity threshold and 76% (95% CI: 72%-80%) for V c , assuming a vaccine with 90% efficacy. The observed vaccination program was estimated to have averted 30 hospitalizations (95% CI: 19–43), associated with over US$490 000 (95% CI: $310 000–700 000) in hospitalization cost. Greater impact was observed with earlier and faster vaccination implementation. Vaccination coverage of at least 77% is likely required to prevent outbreaks of HAV among PEH/PWUD in Louisville, assuming a 90% vaccine efficacy. Proactive hepatitis A vaccination programs among PEH/PWUD will maximize health and economic benefits of these programs and reduce the likelihood of another outbreak. [ABSTRACT FROM AUTHOR]

Abstract: For infections that are typically asymptomatic, targeted surveillance systems (whereby individuals at increased risk are tested more frequently) will detect infections earlier on average than systems with random testing or in systems where all individuals are tested at the same intervals. However, estimating temporal trends in infection risk using data from such targeted surveillance systems can be challenging. This is similarly a problem for targeted surveillance to detect faults of individual industrial components. The incidence of bovine tuberculosis (TB) in British cattle has been generally increasing in the last thirty years. Cattle herds are routinely tested for evidence of exposure to the aetiological bacteria Mycobacterium bovis, in a targeted surveillance programme in which the testing interval is determined by past local TB incidence and local veterinary discretion. The UK Department for Environment, Food and Rural Affairs (Defra) report the monthly percentage of tests on officially TB-free (OTF) herds resulting in a confirmed positive test for M. bovis (i.e. the percentage of tested herds with OTF status withdrawn), which contains substantial fluctuations (three years apart) within the increasing trend. As the number of herds tested changes over time, this cyclic trend is difficult to interpret. Here we evaluate an alternative to the Defra method in which we distribute each incident event across the period at risk to infer the underlying trends in infection incidence using a stochastic model of cattle herd incidence and testing frequencies fitted to data on the monthly number of herds tested and number of these with OTF status withdrawn in 2003–2010. We show that for an increasing underlying incidence trend, the current Defra approach can produce artefactual fluctuations whereas the alternative method described provides more accurate descriptions of the underlying risks over time. [Copyright &y& Elsevier]

Summary: Background: Bovine tuberculosis (TB) has re-emerged as a major problem for British cattle farmers. Failure to control the infection has been linked to transmission from European badgers; badger culling has therefore formed a component of British TB control policy since 1973. Objectives and design: To investigate the impact of repeated widespread badger culling on cattle TB, the Randomised Badger Culling Trial compared TB incidence in cattle herds in and around ten culling areas (each 100km2) with those in and around ten matched unculled areas. Results: Overall, cattle TB incidence was 23.2% lower (95% confidence interval (CI) 12.4–32.7% lower) inside culled areas, but 24.5% (95% CI 0.6% lower–56.0% higher) higher on land ≤2km outside, relative to matched unculled areas. Inside the culling area boundary the beneficial effect of culling tended to increase with distance from the boundary (p =0.085) and to increase on successive annual culls (p =0.064). In adjoining areas, the detrimental effect tended to diminish on successive annual culls (p =0.17). On the basis of such linear trends, the estimated net effect per annum for culling areas similar to those in the trial was detrimental between the first and second culls, but beneficial after the fourth and later culls, for the range of analyses performed. Conclusions: Careful consideration is needed to determine in what settings systematic repeated culling might be reliably predicted to be beneficial, and in these cases whether the benefits of such culling warrant the costs involved. [Copyright &y& Elsevier]

Background The most advanced dengue vaccine candidate is a live-attenuated recombinant vaccine containing the four dengue viruses on the yellow fever vaccine backbone (CYD-TDV) developed by Sanofi Pasteur. Several analyses have been published on the safety and immunogenicity of the CYD-TDV vaccine from single trials but none modelled the heterogeneity observed in the antibody responses elicited by the vaccine. Methods We analyse the immunogenicity data collected in five phase-2 trials of the CYD-TDV vaccine. We provide a descriptive analysis of the aggregated datasets and fit the observed post-vaccination PRNT50 titres against the four dengue (DENV) serotypes using multivariate regression models. Results We find that the responses to CYD-TDV are principally predicted by the baseline immunological status against DENV, but the trial is also a significant predictor. We find that the CYD-TDV vaccine generates similar titres against all serotypes following the third dose, though DENV4 is immunodominant after the first dose. Conclusions This study contributes to a better understanding of the immunological responses elicited by CYD-TDV. The recent availability of phase-3 data is a unique opportunity to further investigate the immunogenicity and efficacy of the CYD-TDV vaccine, especially in subjects with different levels of pre-existing immunity against DENV. Modelling multiple immunological outcomes with a single multivariate model offers advantages over traditional approaches, capturing correlations between response variables, and the statistical method adopted in this study can be applied to a variety of infections with interacting strains. [ABSTRACT FROM AUTHOR]

Summary: Background: The effective control of human and livestock diseases is challenging where infection persists in wildlife populations. The Randomised Badger Culling Trial (RBCT) demonstrated that, while it was underway, proactive badger (Meles meles) culling reduced bovine tuberculosis (TB) incidence inside culled areas but increased incidence in neighboring areas, suggesting that the costs of such culling might outweigh the benefits. Objectives and design: The objective of this study was to investigate whether culling impacts persisted more than one year following the cessation of culling (the ‘post-trial’ period). We compared TB incidence in and around RBCT proactive culling areas with that in and around matched unculled areas. Results: : During the post-trial period, cattle TB incidence inside culled areas was reduced, to an extent significantly greater (p =0.002) than during culling. In neighboring areas, elevated risks observed during culling were not observed post-trial (p =0.038). However, the post-trial effects were comparable to those observed towards the end of the trial (inside RBCT areas: p =0.18 and neighboring areas: p =0.14). Conclusions: Although to-date the overall benefits of culling remain modest, they were greater than was apparent during the culling period alone. Continued monitoring will demonstrate how long beneficial effects last, indicating the overall capacity of such culling to reduce cattle TB incidence. [Copyright &y& Elsevier]

• Machine learning (Boosted Regression Trees) was used to predict case fatality ratios for Ebola virus disease. • The case fatality ratios for Ebola in the West Africa epidemic showed substantial spatiotemporal heterogeneity. • Analysis using geospatial techniques (kriging and semivariograms) revealed that unexplained variation in the case fatality ratio estimates showed spatial autocorrelation but no temporal autocorrelation. • In Ebola outbreaks, machine learning and geospatial analysis, coupled with key domain knowledge, could be used to inform the outbreak response. For the 2013–2016 Ebola epidemic in West Africa, the largest Ebola virus disease (EVD) epidemic to date, we aim to analyse the patient mix in detail to characterise key sources of spatiotemporal heterogeneity in the case fatality ratios (CFR). We applied a non-parametric Boosted Regression Trees (BRT) imputation approach for patients with missing survival outcomes and adjusted for model imperfection. Semivariogram analysis and kriging were used to investigate spatiotemporal heterogeneities. CFR estimates varied significantly between districts and over time over the course of the epidemic. BRT modelling accounted for most of the spatiotemporal variation and interactions in CFR, but moderate spatial autocorrelation remained for distances up to approximately 90 km. Combining district-level CFR estimates and kriged district-level residuals provided the best linear unbiased predicted map of CFR accounting for the both explained and unexplained spatial variation. Temporal autocorrelation was not observed in the district-level residuals from the BRT estimates. This study provides new insight into the epidemiology of the 2013–2016 West African Ebola epidemic with a view of informing future public health contingency planning, resource allocation and impact assessment. The analytical framework developed in this analysis, coupled with key domain knowledge, could be deployed in real time to support the response to ongoing and future outbreaks. [ABSTRACT FROM AUTHOR]

• Vaccination of badgers may reduce the spread of bovine tuberculosis to cattle. • The paper examines evidence of risk compensation and spillover behaviours amongst farmers. • Increased risk taking by farmers is associated with vaccination. • Risk compensation is linked to low self-efficacy amongst farmers. • Lack of spillover behaviour is due to low cultural saliency of vaccination. This paper analyses farmers' behavioural responses to Government attempts to reduce the risk of disease transmission from badgers to cattle through badger vaccination. Evidence for two opposing behavioural adaptions is examined in response to the vaccination of badgers to reduce the risk of transmission to farmed cattle. Risk compensation theory suggests that interventions that reduce risk, such as vaccination, are counterbalanced by negative behavioural adaptions. By contrast, the spillover effect suggests that interventions can prompt further positive behaviours. The paper uses data from a longitudinal mixed methods study of farmers' attitudes to badger vaccination to prevent the spread of bovine tuberculosis, their reports of biosecurity practices, and cattle movement data in 5 areas of England, one of which experienced badger vaccination. Analysis finds limited evidence of spillover behaviours following vaccination. Lack of spillover is attributed to farmers' beliefs in the effectiveness of biosecurity and the lack of similarity between badger vaccination and vaccination for other animal diseases. Risk compensation behaviours are associated with farmers' beliefs as to who should manage animal disease. Rather than farmers' belief in vaccine effectiveness, it is more likely that farmers' low sense of being able to do anything to prevent disease influences their apparent risk compensation behaviours. These findings address the gap in the literature relating to farmers' behavioural adaptions to vaccine use in the management of animal disease. [ABSTRACT FROM AUTHOR]

Summary: Background: The novel Middle East respiratory syndrome coronavirus (MERS-CoV) had, as of Aug 8, 2013, caused 111 virologically confirmed or probable human cases of infection worldwide. We analysed epidemiological and genetic data to assess the extent of human infection, the performance of case detection, and the transmission potential of MERS-CoV with and without control measures. Methods: We assembled a comprehensive database of all confirmed and probable cases from public sources and estimated the incubation period and generation time from case cluster data. Using data of numbers of visitors to the Middle East and their duration of stay, we estimated the number of symptomatic cases in the Middle East. We did independent analyses, looking at the growth in incident clusters, the growth in viral population, the reproduction number of cluster index cases, and cluster sizes to characterise the dynamical properties of the epidemic and the transmission scenario. Findings: The estimated number of symptomatic cases up to Aug 8, 2013, is 940 (95% CI 290–2200), indicating that at least 62% of human symptomatic cases have not been detected. We find that the case-fatality ratio of primary cases detected via routine surveillance (74%; 95% CI 49–91) is biased upwards because of detection bias; the case-fatality ratio of secondary cases was 20% (7–42). Detection of milder cases (or clinical management) seemed to have improved in recent months. Analysis of human clusters indicated that chains of transmission were not self-sustaining when infection control was implemented, but that R in the absence of controls was in the range 0·8–1·3. Three independent data sources provide evidence that R cannot be much above 1, with an upper bound of 1·2–1·5. Interpretation: By showing that a slowly growing epidemic is underway either in human beings or in an animal reservoir, quantification of uncertainty in transmissibility estimates, and provision of the first estimates of the scale of the epidemic and extent of case detection biases, we provide valuable information for more informed risk assessment. Funding: Medical Research Council, Bill & Melinda Gates Foundation, EU FP7, and National Institute of General Medical Sciences. [ABSTRACT FROM AUTHOR]

Abstract: Infectious diseases impact African wild dogs (Lycaon pictus), but the nature and magnitude of this threat likely varies among populations according to different factors, such as the presence and prevalence of pathogens and land-use characteristics. We systematically evaluated these factors to assist development of locally appropriate strategies to mitigate disease risk. Wild dogs from 16 sites representing five unconnected populations were examined for rabies virus, canine distemper virus (CDV), canine parvovirus, canine coronavirus, and Babesia spp. exposure. Analyses revealed widespread exposure to viral pathogens, but Babesia was never detected. Exposure to CDV was associated with unprotected and protected-unfenced areas where wild dogs likely have a high probability of domestic dog contact and, in the case of protected-unfenced areas, likely reside amongst high wildlife densities. Our findings also suggest that domestic dog contact may increase rabies and coronavirus exposure risk. Therefore, domestic dogs may be a source of CDV, rabies and coronavirus, while wildlife may also play an important role in CDV transmission dynamics. Relatively high parvovirus seroprevalence across land-use types suggests that it might persist in the absence of spillover from domestic dogs. Should intervention be needed to control pathogens in wild dogs, efforts to prevent rabies and coronavirus exposure might be directed at reducing infection in the presumed domestic dog reservoir through vaccination. If prevention of CDV and parvovirus infections were deemed a management necessity, control of disease in domestic dogs may be insufficient to reduce transmission risks, and vaccination of wild dogs themselves may be the optimal strategy. [Copyright &y& Elsevier]

Abstract: Schistosoma japonicum is an important parasite in terms of clinical, veterinary and socio-economic impacts, and rodents, a long neglected reservoir for the parasite, have recently been found to act as reservoir hosts in some endemic areas of China. Any difference in the host’s biological characteristics and/or associated living habitats among rodents may result in different environments for parasites, possibly resulting in a specific population structure of parasites within hosts. Therefore knowledge of the genetic structure of parasites within individual rodents could improve our understanding of transmission dynamics and hence our ability to develop effective control strategies. In this study, we aimed to describe a host-specific structure for S. japonicum and its potential influencing factors. The results showed a significant genetic differentiation among hosts. Two factors, including sampling seasons and the number of miracidia genotyped per host, showed an effect on the genetic diversity of an infrapopulation through a univariable analysis but not a multivariable analysis. A possible scenario of clustered infection foci and the fact of multiple definitive host species, the latter of which is unique to S. japonicum compared with other schistosomes, were proposed to explain the observed results and practical implications for control strategies are recommended. [Copyright &y& Elsevier]

Abstract: Schistosomiasis japonica is a disease of profound medical and veterinary importance which has remained endemic in many regions and has re-emerged where previously controlled in China. Although over 40 mammalian species are suspected as reservoirs for Schistosoma japonicum, their relative roles, particularly wildlife, remain to be ascertained. As cercarial emergence is a heritable trait shaped by the definitive hosts’ behaviour, three chronobiological trials of cercarial emergence from field-collected snails from two contrasting ecological regions within China were performed, followed by genetic analyses of the parasites. Two distinct modes were identified, with late afternoon emergence mainly found in the hill region, compatible with a nocturnal rodent reservoir, and early emergence within the marshland consistent with a diurnal cattle reservoir. Furthermore, genetic analyses pointed to a clear separation between cercariae with different biological traits. The phenotypic and genotypic differentiation of the parasites identified here between and within two regions may indicate a strain complex. Such parasite diversity could, in turn, provide an explanation for the different infection scenarios observed between the two regions, and hence have important applied implications in terms of targeted control of key reservoirs. [Copyright &y& Elsevier]

Summary: Objective: The 2009 pandemic of influenza A (H1N1) has disproportionately affected children and young adults, resulting in attention by public health officials and the news media on schools as important settings for disease transmission and spread. We aimed to characterize US schools affected by novel influenza A (H1N1) relative to other schools in the same communities. Methods: A database of US school-related cases was obtained by electronic news media monitoring for early reports of novel H1N1 influenza between April 23 and June 8, 2009. We performed a matched case–control study of 32 public primary and secondary schools that had one or more confirmed cases of H1N1 influenza and 6815 control schools located in the same 23 counties as case schools. Results: Compared with controls from the same county, schools with reports of confirmed cases of H1N1 influenza were less likely to have a high proportion of economically disadvantaged students (adjusted odds ratio (aOR) 0.385; 95% confidence interval (CI) 0.166–0.894) and less likely to have older students (aOR 0.792; 95% CI 0.670–0.938). Conclusions: We conclude that public schools with younger, more affluent students may be considered sentinels of the epidemic and may have played a role in its initial spread. [ABSTRACT FROM AUTHOR]