Zoonotic diseases affect resource-poor tropical communities disproportionately, and are linked to human use and modification of ecosystems. Disentangling the socio-ecological mechanisms by which ecosystem change precipitates impacts of pathogens is critical for predicting disease risk and designing effective intervention strategies. Despite the global "One Health" initiative, predictive models for tropical zoonotic diseases often focus on narrow ranges of risk factors and are rarely scaled to intervention programs and ecosystem use. This study uses a participatory, co-production approach to address this disconnect between science, policy and implementation, by developing more informative disease models for a fatal tick-borne viral haemorrhagic disease, Kyasanur Forest Disease (KFD), that is spreading across degraded forest ecosystems in India. We integrated knowledge across disciplines to identify key risk factors and needs with actors and beneficiaries across the relevant policy sectors, to understand disease patterns and develop decision support tools. Human case locations (2014-2018) and spatial machine learning quantified the relative role of risk factors, including forest cover and loss, host densities and public health access, in driving landscape-scale disease patterns in a long-affected district (Shivamogga, Karnataka State). Models combining forest metrics, livestock densities and elevation accurately predicted spatial patterns in human KFD cases (2014-2018). Consistent with suggestions that KFD is an "ecotonal" disease, landscapes at higher risk for human KFD contained diverse forest-plantation mosaics with high coverage of moist evergreen forest and plantation, high PLOS NEGLECTED TROPICAL DISEASES

Background There is a strong policy impetus for the One Health cross-sectoral approach to address the complex challenge of zoonotic diseases, particularly in low/lower middle income countries (LMICs). Yet the implementation of this approach in LMIC contexts such as India has proven challenging, due partly to the relatively limited practical guidance and understanding on how to foster and sustain cross-sector collaborations. This study addresses this gap by exploring the facilitators of and barriers to successful convergence between the human, animal and environmental health sectors in India. Methods A mixed methods study was conducted using a detailed content review of national policy documents and in-depth semi-structured interview data on zoonotic disease management in India. In total, 29 policy documents were reviewed and 15 key informant interviews were undertaken with national and state level policymakers, disease managers and experts operating within the human-animal-environment interface of zoonotic disease control. Results Our findings suggest that there is limited policy visibility of zoonotic diseases, although global zoonoses, especially those identified to be of pandemic potential by international organisations (e.g. CDC, WHO and OIE) rather than local, high burden endemic diseases, have high recognition in the existing policy agenda setting. Despite the widespread acknowledgement of the importance of cross-sectoral collaboration, a myriad of factors operated to either constrain or facilitate the success of cross-sectoral convergence at different stages (i.e. information-sharing, undertaking common activities and merging resources and infrastructure) of cross-sectoral action. Importantly, participants identified the lack of supportive policies, conflicting departmental priorities and limited institutional capacities as major barriers that hamper effective cross-sectoral collaboration on zoonotic disease control. Building on existing informal inter-personal relationships and collaboration platforms were suggested by participants as the way forward. Conclusion Our findings point to the importance of strengthening existing national policy frameworks as a first step for leveraging cross-sectoral capacity for improved disease surveillance and interventions. This requires the contextual adaptation of the One Health approach in a manner that is sensitive to the underlying socio-political, institutional and cultural context that determines and shapes outcomes of cross-sector collaborative arrangements.

Zoonoses disproportionately affect tropical communities and are associated with human modification and use of ecosystems. Effective management is hampered by poor ecological understanding of disease transmission and often focuses on human vaccination or treatment. Better ecological understanding of multi-vector and multi-host transmission, social and environmental factors altering human exposure, might enable a broader suite of management options. Options may include “ecological interventions” that target vectors or hosts and require good knowledge of underlying transmission processes, which may be more effective, economical, and long lasting than conventional approaches. New frameworks identify the hierarchical series of barriers that a pathogen needs to overcome before human spillover occurs and demonstrate how ecological interventions may strengthen these barriers and complement human-focused disease control. We extend these frameworks for vector-borne zoonoses, focusing on Kyasanur Forest Disease Virus (KFDV), a tick-borne, neglected zoonosis affecting poor forest communities in India, involving complex communities of tick and host species. We identify the hierarchical barriers to pathogen transmission targeted by existing management. We show that existing interventions mainly focus on human barriers (via personal protection and vaccination) or at barriers relating to Kyasanur Forest Disease (KFD) vectors (tick control on cattle and at the sites of host (monkey) deaths). We review the validity of existing management guidance for KFD through literature review and interviews with disease managers. Efficacy of interventions was difficult to quantify due to poor empirical understanding of KFDV–vector–host ecology, particularly the role of cattle and monkeys in the disease transmission cycle. Cattle are hypothesised to amplify tick populations. Monkeys may act as sentinels of human infection or are hypothesised to act as amplifying hosts for KFDV, but the spatial scale of risk arising from ticks infected via monkeys versus small mammal reservoirs is unclear. We identified 19 urgent research priorities for refinement of current management strategies or development of ecological interventions targeting vectors and host barriers to prevent disease spillover in the future.

Background Zoonotic diseases disproportionately affect poor tropical communities. Transmission dynamics of zoonoses are complex, involving communities of vector and animal hosts, with human behaviour and ecosystem use altering exposure to infected vectors and hosts. This complexity means that efforts to manage and prevent human spillover are often hampered by a poor ecological evidence base and intervention strategies tend to focus on humans (e.g. vaccination, preventative drug treatment). However, integrating ecological and evolutionary understanding of multi-vector and host transmission, human and environmental factors into disease control policy is essential. Recent frameworks have been developed to guide appropriate design of “ecological interventions” which have the potential for being more long-term, effective and economical approaches to managing human disease.Results We extended new frameworks to identify the hierarchical series of barriers that need to be overcome by a vector-borne pathogen to facilitate human spillover, focusing on an emerging, tick-borne zoonotic pathogen in India, Kyasanur Forest Disease Virus (KFDV). Current management recommendations focus on human barriers, through personal protection and vaccination, as well as targeting vector control on cattle and at the sites of monkey deaths. Assessment of the validity of current management practices for KFD through literature review and interviews with disease managers found the efficacy of interventions difficult to quantify, due to poor empirical evidence and a lack of understanding of KFDV-vector-host ecology, particularly regarding the role of cattle in amplifying tick populations and the spatial scale of risk arising from ticks infected via monkeys, which are considered to be amplifying hosts for KFDV. The spraying of malathion around dead monkeys and the burning of vegetation to reduce tick abundance were particularly unfounded interventions. The need for community guidance and education in best practice for tick-prevention and improved vaccine efficacy and surveillance were also identified. We highlight 18 urgent research priorities and identify those which could refine current management strategies or facilitate ecological interventions targeting vectors and host barriers to spillover in the future. Conclusions We emphasise that inter-disciplinary One Health approaches involving collaboration across diverse disciplines including ecology, epidemiology, animal and public health, health systems and social sciences, and with meaningful involvement of local communities, are necessary to refine predictive models of spillover, develop new interventions and target vaccination strategies and surveillance more effectively. Applying such approaches to understand the complex ecological systems involved in zoonotic spillover, and refine and develop appropriate management interventions, including ecological interventions targeting non-human barriers, will ultimately lead to more sustainable and long-term reductions in human cases of neglected zoonoses in the future.

Summary Bluetongue is endemic in India and has been reported from most Indian states. Of late, the clinical disease is most frequently seen in the states of Andhra Pradesh, Telangana (erstwhile Andhra Pradesh state), Tamil Nadu and Karnataka. Our analysis of diagnostic samples from bluetongue outbreaks during 2010–2011 from the state of Karnataka identified bluetongue virus (BTV) serotype 5 (BTV‐5) for the first time in India. One of the diagnostic samples (CH1) and subsequent virus isolate (IND2010/02) contained both BTV‐2 and BTV‐5. Segment 2 (seg‐2) sequence data (400 bp: nucleotides 2538–2921) for IND2010/02‐BTV5, showed 94.3% nucleotide identity to BTV‐5 from South Africa (Accession no. AJ585126), confirming the virus serotype and also indicating that Seg‐2 was derived from a Western topotype, which is in contrast to serotype 2, that belongs to an Eastern topotype. BTV‐5 has been recently reported from Africa, China, French islands and the Americas. Although the exact source of the Indian BTV‐5 isolate is still to be confirmed, recent identification of additional exotic serotypes in India is of real concern and might add to the severity of the disease seen in these outbreaks.