Modeling highly pathogenic avian influenza transmission in wild birds and poultry in West Bengal, India.

Wild birds are suspected to have played a role in highly pathogenic avian influenza (HPAI) H5N1 outbreaks in West Bengal. Cluster analysis showed that H5N1 was introduced in West Bengal at least 3 times between 2008 and 2010. We simulated the introduction of H5N1 by wild birds and their contact with poultry through a stochastic continuous-time mathematical model. Results showed that reducing contact between wild birds and domestic poultry, and increasing the culling rate of infected domestic poultry communities will reduce the probability of outbreaks. Poultry communities that shared habitat with wild birds or those indistricts with previous outbreaks were more likely to suffer an outbreak. These results indicate that wild birds can introduce HPAI to domestic poultry and that limiting their contact at shared habitats together with swift culling of infected domestic poultry can greatly reduce the likelihood of HPAI outbreaks

A model to control the epidemic of H5N1 influenza at the source

<p>Abstract</p> <p>Background</p> <p>No country is fully prepared for a 1918-like pandemic influenza. Averting a pandemic of H5N1 influenza virus depends on the successful control of its endemicity, outbreaks in poultry and occasional spillage into human which carries a case-fatality rate of over 50%. The use of perimetric depopulation and vaccination has failed to halt the spread of the epidemic. Blanket vaccination for all poultry over a large geographical area is difficult. A combination of moratorium, segregation of water fowls from chickens and vaccination have been proved to be effective in the Hong Kong Special Administrative Region (HKSAR) since 2002 despite endemicity and outbreaks in neighbouring regions. Systematic surveillance in southern China showed that ducks and geese are the primary reservoirs which transmit the virus to chickens, minor poultry and even migratory birds.</p> <p>Presentation of the hypothesis</p> <p>We hypothesize that this combination of moratorium, poultry segregation and targeted vaccination if successfully adapted to an affected district or province in any geographical region with high endemicity would set an example for the control in other regions.</p> <p>Testing the hypothesis</p> <p>A planned one-off moratorium of 3 weeks at the hottest month of the year should decrease the environmental burden as a source of re-infection. Backyard farms will then be re-populated by hatchlings from virus-free chickens and minor poultry only. Targeted immunization of the ducks and geese present only in the industrial farms and also the chickens would be strictly implemented as blanket immunization of all backyard poultry is almost impossible. Freely grazing ducks and geese would not be allowed until neutralizing antibodies of H5 subtype virus is achieved. As a proof of concept, a simple mathematical model with susceptible-infected-recovered (SIR) structure of coupled epidemics between aquatic birds (mainly ducks and geese) and chickens was used to estimate transmissibility within and between these two poultry populations. In the field the hypothesis is tested by prospective surveillance of poultry and immunocompetent patients hospitalized for severe pneumonia for the virus before and after the institution of these measures.</p> <p>Implications of the Hypothesis</p> <p>A combination of targeted immunization with the correct vaccine, segregation of poultry species and moratorium of poultry in addition to the present surveillance, biosecurity and hygienic measures at the farm, market and personal levels could be important in the successful control of the H5N1 virus in poultry and human for an extensive geographical region with continuing outbreaks. Alternatively a lesser scale of intervention at the district level can be considered if there is virus detection without evidence of excess poultry deaths since asymptomatic shedding is common in waterfowls.</p

Model-Based Evaluation of Highly and Low Pathogenic Avian Influenza Dynamics in Wild Birds

There is growing interest in avian influenza (AI) epidemiology to predict disease risk in wild and domestic birds, and prevent transmission to humans. However, understanding the epidemic dynamics of highly pathogenic (HPAI) viruses remains challenging because they have rarely been detected in wild birds. We used modeling to integrate available scientific information from laboratory and field studies, evaluate AI dynamics in individual hosts and waterfowl populations, and identify key areas for future research. We developed a Susceptible-Exposed-Infectious-Recovered (SEIR) model and used published laboratory challenge studies to estimate epidemiological parameters (rate of infection, latency period, recovery and mortality rates), considering the importance of age classes, and virus pathogenicity. Infectious contact leads to infection and virus shedding within 1–2 days, followed by relatively slower period for recovery or mortality. We found a shorter infectious period for HPAI than low pathogenic (LP) AI, which may explain that HPAI has been much harder to detect than LPAI during surveillance programs. Our model predicted a rapid LPAI epidemic curve, with a median duration of infection of 50–60 days and no fatalities. In contrast, HPAI dynamics had lower prevalence and higher mortality, especially in young birds. Based on field data from LPAI studies, our model suggests to increase surveillance for HPAI in post-breeding areas, because the presence of immunologically naïve young birds is predicted to cause higher HPAI prevalence and bird losses during this season. Our results indicate a better understanding of the transmission, infection, and immunity-related processes is required to refine predictions of AI risk and spread, improve surveillance for HPAI in wild birds, and develop disease control strategies to reduce potential transmission to domestic birds and/or humans

Connecting the study of wild influenza with the potential for pandemic disease

Continuing outbreaks of pathogenic (H5N1) and pandemic (SOIVH1N1) influenza have underscored the need to understand the origin, characteristics, and evolution of novel influenza A virus (IAV) variants that pose a threat to human health. In the last 4–5 years, focus has been placed on the organization of large-scale surveillance programs to examine the phylogenetics of avian influenza virus (AIV) and host–virus relationships in domestic and wild animals. Here we review the current gaps in wild animal and environmental surveillance and the current understanding of genetic signatures in potentially pandemic strains.National Institute of Allergy and Infectious Diseases (U.S.) (Contract HHSN266200700010C)Massachusetts Institute of Technolog

The Pattern of Highly Pathogenic Avian Influenza H5N1 Outbreaks in South Asia

ighly pathogenic avian influenza (HPAI) H5N1 has caused severe illnesses in poultry and in humans. More than 15,000 outbreaks in domestic birds from 2005 to 2018 and 861 human cases from 2003 to 2019 were reported across the world to OIE (Office International des Epizooties) and WHO (World Health Organization), respectively. We reviewed and summarized the spatial and temporal distribution of HPAI outbreaks in South Asia. During January 2006 to June 2019, a total of 1063 H5N1 outbreaks in birds and 12 human cases for H5N1 infection were reported to OIE and WHO, respectively. H5N1 outbreaks were detected more in the winter season than the summer season and PubMed to collect data from published articles using the followin

Food risks and consumer trust : European governance of Avian influenza

During the 1990s, many European countries faced one or more food crises, such as bovine spongiform encephalopathy (BSE), E. coli, dioxin residues, and foot-and-mouth disease. These crises were marked by a growing public recognition of food-related risks and the changing nature of these risks, and tended to undermine citizen-consumer trust in the practices and institutions that managed food safety. To restore and retain trust in food throughout Europe, the European food policy framework was substantially renewed at the turn of the century. Conventional food governance was the domain of scientific experts, state agents and actors higher in the food supply chain, who decided on policy measures based on scientific data, and subsequently conveyed them to the general public. In the renewed framework for governing food, other social actors, including (individual and organised) citizen-consumers, were to be more actively involved through innovative roles. While this innovative position for citizen-consumers represents a definite discursive shift, it remains rather elusive how citizen-consumers should be included in food risk governance practices, and what effects such inclusion has on consumer trust. This study aims to further the understanding of whether and how citizen-consumer involvement in European food risk governance (re)establishes trust in the handling of food risks. It investigates consumer involvement within the conventional policy institutions (at the EU and Member State levels), as well as outside of these institutions (at shopping floors and in mass-media). The study focuses empirically on a major risk to Europe that emerged after the renewed policy framework had largely been implemented: highly pathogenic avian influenza H5N1. In August 2005, this avian influenza virus strain entered European public arenas as the next food and agricultural risk. As the virus was detected close to Europe, questions arose whether measures were required to protect human health and secure European food supply. Chapter 2 analyses the public debates on the characteristics of the risk and on the interventions needed. The mass media in two EU Member States, the UK and the Netherlands, were studied for this purpose. With the help of qualitative analysis the debates were analysed as they unfolded in selected national newspapers. Arguing that risks are socially mediated realities, this chapter discusses how struggles on risk definitions relate to different policy decisions. Moreover, it analyses how these political dynamics are informed by the involvement of state, market, science, and civil society actors, and discerns their implications for the functioning of the EU food governance framework. Chapter 3 explores consumer perspectives on food safety governance by expounding the results of an explorative study among Dutch consumers. Moving away from the ‘knowledge deficit’ model, which entails that consumers should be better educated to avoid ‘irrational’ responses, we investigate what consumers consider at the place and time they actually have to deal with food risks. To give ample room for the construction of contextual knowledge, consumers of poultry meat were questioned at various retailers by applying a qualitative interviewing method. From this research, it is concluded that multiple consumer rationalities about food safety governance exist. As a consequence of the existence of these multiple consumer rationalities, a differentiated governance approach to restore or retain consumer confidence is more likely to be pertinent than a ‘one-size-fits-all’ approach. Chapter 4 starts from the observation that, irrespective of the major food crises that occurred during the 2000s, consumer trust in food seems to remain high in Western Europe. Information provision to consumers on food risks is a central strategy of the EU, its Member States and private food providers to build food trust among consumers. But can the interpretation of such information by consumers explain these high levels of trust? Following recent outbreaks of avian influenza in the UK, this paper investigates the constitution of food trust among UK poultry consumers by focusing on the place where relevant consumer decisions are made: the shopping floor. In-store qualitative interviews with consumers of a variety of poultry products at different shops are used to reveal the role of information in constructing trust. It is concluded that besides on knowledge inducted from information provided, trust depends as much on consumer strategies to handle non-knowing of food risks. Three main forms of trust relations are distinguished, which together result in high levels of consumer trust at a system level. Chapter 5 studies the institutional incorporation of social interests and values in EU and Member State food risk governance. The study is based on qualitative analyses of key official publications and press releases from Member State and EU level bodies, as well as from scientists, NGOs and food supply chain actors. These analyses are combined with 40 in-depth interviews with relevant food system actors. The chapter reviews how and which social interests and values are incorporated in food risk governance in the Netherlands, France and the UK, and at the EU level. It concludes that predominantly through state-level political (and to a lesser extent: scientific) domains social interests and values were articulated on the EU agenda, while at the EU level food risk governance remained principally justified on the basis of scientific evidence. The chapter finishes with discerning the effects of this inclusion of social interest and values on public trust and the functioning of the internal market. The sixth and final chapter draws conclusions on the changing positions of, and relations between, scientists, policy makers, market actors and citizen-consumers. First, while natural scientists have lost their position as the a priori trustworthy source of risk information, they still maintain a central position in legitimating risk definitions. Yet, in this position scientists have become more transparent than in the past concerning their internal disagreements, and are (more overtly) incorporating wider social, economic and political arguments in their policy advice. Herewith, these scientists become more susceptible to public contestation, and risk assessment opens up for non-scientific actors aiming to publicly legitimate their own perspectives. In essence, this changing public character of risk assessments entails the conflation of two previously segregated risk governance phases: those of risk assessment and communication. With such communication, citizen-consumers are ‘invited’ or even ‘forced’ to conduct micro-level assessments and judgements of conflicting risk characterisations. Second, due to the dissolution of science as the uncontested source of risk characterisation, risk managers can no longer assume that they can legitimate their decisions by referring to scientific risk assessments, and the cost-benefit analyses based on them. Instead, policy makers are urged to base decisions also (more explicitly) on wider social interests and values and legitimate their handling of risks in view of scientific non-knowing. This is especially the case when risk knowledge bases are subject to public contestation, and when wider social perspectives on the appropriateness of different risk governance options diverge. In such situations, different risk perspectives may become dominant in different countries, as risks are mediated through different culturally-embedded and socially contextualised sense-making frames. Due to this differentiation, European Member States (re-)emerge as pivotal governance actors: while EU level food risk governance remains grounded in scientific-rational and technically-based justification which safeguards a minimum level of European policy harmonisation, more room has to be opened for the Member States to incorporate country-specific social interests and values in their decisions. Third, the possibilities for Member States to differentiate from a harmonised European food risk governance arrangement entailed increased room for private actors to become—legitimately—involved. By refusing to retail products whose characteristics were co-determined by Member State-specific measures, supermarkets became strongly involved in food risk governance—and were decisive in the success of such measures. Supermarkets legitimated their involvement with the argument of retaining their consumers’ trust in food. Fourth, citizen-consumers take on roles as micro-level assessors of conflicting risk characterisations, which ‘materialises’ in consumers’ co-governance of food risks through their consumption practices. With such consumer co-governance, consumption turns political, marking a partial shift of risk management practices towards places where consumers stand in ‘direct’ relation to the risk governors in the food supply and management systems: the shopping floors. On shopping floors, consumers differ in their perspectives on risks and on how to govern these. Hence, providing room for Member State-based differentiation in risk management does not necessarily mean one addresses all consumer rationalities, as for groups of consumers such management decisions may lack congruence with their perspectives and concerns. Moreover, political and policy institutions encounter difficulties to address in their risk management decisions the socio-contextual embeddedness of consumers, consumption practices and trust. Significant groups of consumers do not regard themselves merely as passive recipients of food products, information flows and governance outcomes. They are self-defined co-governors of the safety of food through their acts of buying food and relating to the relevant actor networks. Within these relations and co-constructions consumer trust is being built. As such, European and national policy institutions may contribute to the make-up of the constraining and enabling environment of the shopping floor, but these institutions cannot fully construct and determine consumer trust. Hence, we observed an increased involvement of (interests and values of) citizen-consumer in institutional risk assessment and management practices—particularly through Member State-level political domains. At the same time, risk assessment and management dynamics shift for an important part to contexts and practices outside of conventional, political and policy institutions: to the mass-media and shopping floors. Besides policy challenges, these dynamics entail opportunities for improving the European food risk governance process, which are set out in policy recommendations for different groups of governance actors. The study finishes with making some recommendations for further research. <br/

Pathogen dynamics in wild bird species: circulation of avian influenza viruses in natural vs. anthropic ecosystems and concurrent infections with other agents in waterbirds

170 p.El virus influenza A (Influenzavirus A) es el agente etiológico de la influenza aviar. Los virus de la influenza aviar (VIA) circulan de forma natural entre las aves acuáticas de todo el mundo y pueden infectar a las aves de domésticas y a los mamíferos, incluido el ser humano, aunque en este último las infecciones no son frecuentes. Las aves acuáticas silvestres se consideran los reservorios naturales del virus aunque la infección rara vez transcurre con signos clínicos. El virus se replica tanto en el tracto intestinal como en el respiratorio de las aves infectadas y se puede mantener en los ecosistemas acuáticos durante largos periodos de tiempo. Los VIA se transmiten fácilmente entre las aves y algunos subtipos pueden hacer enfermar o incluso matar a ciertas especies, siendo especialmente susceptibles algunas especies de aves domésticas, como los pollos, los pavos o las codornices. Los VIAs se clasifican en VIA de baja patogenicidad y VIA altamente patógenos en función de sus características moleculares y de la capacidad que tienen de causar enfermedad o mortalidad en pollos. Esta Tesis Doctoral la componen cuatro capítulos en los que se estudia la epidemiologia de los VIA desde diferentes abordajes. Además, para profundizar en el conocimiento de la epidemiología de los VIA se ha llevado a cabo una revisión de la bibliografía existente.En primer lugar y debido a que la epidemiología de los VIA es compleja y afecta a hospedadores de diversas especies, se ha llevado a cabo un estudio de larga duración en un humedal de pequeñas dimensiones. En este humedal se ha profundizado, mediante el uso de técnicas no invasivas, en la epidemiologia del VIA en relación con la ecología y la composición de la comunidad de aves presentes en el humedal y las condiciones meteorológicas. Los resultados revelaron diferencias estacionales en la prevalencia de VIA, observándose las prevalencias más altas en la época de cría. El modelo matemático realizado indicó que las fluctuaciones a largo plazo en la prevalencia de VIA y potencialmente la diversidad de subtipos, se encontraban moduladas por el número de parejas Anseriformes reproductoras en el humedal. En el segundo estudio se abordó la epidemiología de VIA en los paseriformes, debido a la ubicuidad de este orden y a la diversidad de características ecológicas de las especies que lo integran. Gracias a este trabajo se pudo comprobar que las especies más frecuentemente infectadas con VIA procedían de la vertiente Atlántica y mostraban una mayor tolerancia a cambios en la altitud geográfica. Este trabajo refuerza la importancia del entorno y de las características intrínsecas de cada especie en la detección de los VIA.En el tercer estudio se monitorizó, mediante técnicas no invasivas, la prevalencia de los VIA en un ambiente humanizado, como son los vertederos de residuos urbanos, estudiando las especies de aves acuáticas que se agregan en ellos durante la invernada. Las aves estudiadas mostraron una prevalencia baja de VIA, pero el hallazgo de los mismos subtipos en especies diferentes sugiere que los vertederos podrían ser importantes lugares de transmisión de los VIA.Estos tres capítulos ponen en evidencia tres escenarios clave en la epidemiología de los VIA; un estudio longitudinal en un ecosistema natural con una presencia importante de reservorios, un estudio en un orden menos conocido desde el punto de la epidemiología de los VIA, pero que frecuentan una gran diversidad de ambientes naturales y humanizados y por último un estudio en un ecosistema artificial, como son los vertederos de residuos urbanos, con agregación temporal de aves acuáticas.El núcleo de la tesis culmina con un cuarto estudio cuyo objetivo es verificar si la excreción de los VIA está relacionada con la presencia de otros microorganismos que coinfectan a las aves acuáticas. En este estudio se observó que la infección con VIA incrementaba la posibilidad de detectar otras agentes en las muestras estudiadas. Además, la circulación concomitante de varios de los agentes seleccionados se produjo únicamente en las muestras positivas a VIA, lo que sugiere que la infección con VIA podría facilitar la infección con otros agentes. De forma más concreta, se comprobó que la prevalencia de Mycobacterium sp. y Salmonella sp. era más alta en los animales infectados con VIA, frente a los que no lo estaban. Por todo lo anteriormente mencionado esta Tesis aporta información nueva y relevante en relación con la epidemiología de los virus influenza aviar en relación con la ecología de los hospedadores silvestres y de los ecosistemas naturales o artificiales en los que viven.Neiker Tecnali

Influenza A H5N1 and H7N9 in China: A spatial risk analysis

abstract: Background Zoonotic avian influenza poses a major risk to China, and other parts of the world. H5N1 has remained endemic in China and globally for nearly two decades, and in 2013, a novel zoonotic influenza A subtype H7N9 emerged in China. This study aimed to improve upon our current understanding of the spreading mechanisms of H7N9 and H5N1 by generating spatial risk profiles for each of the two virus subtypes across mainland China. Methods and findings In this study, we (i) developed a refined data set of H5N1 and H7N9 locations with consideration of animal/animal environment case data, as well as spatial accuracy and precision; (ii) used this data set along with environmental variables to build species distribution models (SDMs) for each virus subtype in high resolution spatial units of 1km[superscript 2] cells using Maxent; (iii) developed a risk modelling framework which integrated the results from the SDMs with human and chicken population variables, which was done to quantify the risk of zoonotic transmission; and (iv) identified areas at high risk of H5N1 and H7N9 transmission. We produced high performing SDMs (6 of 8 models with AUC > 0.9) for both H5N1 and H7N9. In all our SDMs, H7N9 consistently showed higher AUC results compared to H5N1, suggesting H7N9 suitability could be better explained by environmental variables. For both subtypes, high risk areas were primarily located in south-eastern China, with H5N1 distributions found to be more diffuse and extending more inland compared to H7N9. Conclusions We provide projections of our risk models to public health policy makers so that specific high risk areas can be targeted for control measures. We recommend comparing H5N1 and H7N9 prevalence rates and survivability in the natural environment to better understand the role of animal and environmental transmission in human infections.The article is published at http://journals.plos.org/plosone/article?id=10.1371/journal.pone.017498

Chapter 3: One Health, One Medicine

In recognition that the health of humans, animals, and the environment is linked, One Health seeks to increase communication and collaboration across the disciplines in order to promote, improve, and defend the health of all species on the planet. This strategy may seem simple, but unfortunately it will not be easy to implement. The explosion of medical knowledge in the 20th century led to academic, governmental, and industrial silos of specialization; these silos fostered a compartmentalized approach to health and disease. Building bridges across these silos will require leadership, joint educational programs, financial support, and other strategies that promote transdisciplinary efforts. Before the 20th century, physicians typically worked with veterinary medical colleagues and others to improve the health of humans and animals. This chapter will describe the historical developments in medicine and veterinary medicine leading to the current status quo. It will provide examples of why the status quo is problematic and will highlight the challenges in changing the present paradigm. It will conclude with recommendations on how to implement a One Health approach in the future

Ecohealth research in Southeast Asia : past, present and the way forward

Ecohealth is a comprehensive approach to understanding health at its human, animal and environmental interface in a socio-ecological systems context. This approach was introduced widely in Southeast Asia (SEA) by the Canadian International Development Research Centre (IDRC) in the late 2000s. Aimed at addressing the problem of emerging infectious diseases (EIDs), numerous such projects and activities have been generated throughout the region. Ecohealth is increasingly converging with the One Health approach, as both movements emphasise a holistic understanding to health. We conducted a scoping review by considering all of the Ecohealth programmes, initiatives and projects that have been implemented in SEA since the introduction of the approach, and also gathered information from peer-reviewed literature. The objective of this paper is to review Ecohealth activities within SEA over the last 10 years to address the lessons learned, challenges faced and the way forward for Ecohealth in the region. Activities range from those focusing purely on capacity, projects focusing on research and projects covering both. Achievements to date include, for example, research contributing to the field of infectious diseases in relation to social ecological factors and associated urbanisation and agricultural intensification. Challenges remain at the project design and implementation level, in the available capacity and coordination to develop Ecohealth research teams in the countries, gauging teams' assimilation of Ecohealth's underlying tenets and their translation into sustainable disease prevention and control, as well as in the ability to scale up Ecohealth projects. We suggest that the way forward for Ecohealth should be from a regional perspective in terms of research, training and policy translation using Ecohealth in combination with the One Health approach