Biosecurity and geospatial analysis of mycoplasma infections in poultry farms at Al-Jabal Al-Gharbi region of Libya

Geospatial database of farm locations and biosecurity measures are essential to control disease outbreaks. A study was conducted to establish geospatial database on poultry farms in Al-Jabal Al-Gharbi region of Libya, to evaluate the biosecurity level of each farm and to determine the seroprevalence of mycoplasma and its relation to biosecurity level. A field team of 7 Veterinarians belongs to the National Center of Animal Health was assigned for data recording and collection of blood samples. Personal information of the producers, geographical locations, biosecurity measures and description of the poultry farms were recorded. The total number of poultry farms in Al-Jabal Al-Gharbi Region is 461 farms distributed in 13 cities. Out of these, 102 broiler farms and one broiler breeder farm (10 houses) which were in operation during team visit were included in this study. Following collection of blood, sera were separated and tested by Enzyme-linked immunosorbent assay (ELISA) for the presence of antibodies against Mycoplasma (General antigen for M. gallisepticum and M. synoviae). The seroprevalence of Mycoplasma in the region was 28% (29 poultry farms out of 103 were infected). About 50% (23 out of 47) of poultry farms located in Garian city were infected with Mycoplasma and one significant cluster of Mycoplasma infection in the city was identified. Low level of biosecurity was found in poultry farms of the region. Out of the 103 farms included, 63% of poultry houses has a ground of soil and 44% of them has uncoated walls which may influence the proper cleaning and disinfection. Almost 100% of the farms are at risk of exposure to diseases transmitted by wild birds such as avian influenza and Newcastle disease due to absence of wild birds control program. Although, 81% of the farms have entry restrictions, only 20% have disinfectants at entry which increase the risk of exposure to pathogens. The results of this study highlight the weakness points of biosecurity measures in poultry farms of Al-Jabal Al-Gharbi region and high seroprevalence of mycoplasma. Data collected in this study will assist the Veterinary authorities to apply effective disease control strategies.Keywords: Biosecurity, Geospatial analysis, Mycoplasma, Poultry

Spatiotemporal reconstruction and transmission dynamics during the 2016-17 H5N8 highly pathogenic avian influenza epidemic in Italy

Effective control of avian diseases in domestic populations requires understanding of the transmission dynamics facilitating viral emergence and spread. In 2016–17, Italy experienced a significant avian influenza epidemic caused by a highly pathogenic A(H5N8) virus, which affected domestic premises housing around 2.7 million birds, primarily in the north‐eastern regions with the highest density of poultry farms (Lombardy, Emilia‐Romagna and Veneto). We perform integrated analyses of genetic, spatiotemporal and host data within a Bayesian phylogenetic framework. Using continuous and discrete phylogeography, we estimate the locations of movements responsible for the spread and persistence of the epidemic. The information derived from these analyses on rates of transmission between regions through time can be used to assess the success of control measures. Using an approach based on phylogenetic–temporal distances between domestic cases, we infer the presence of cryptic wild bird‐mediated transmission, information that can be used to complement existing epidemiological methods for distinguishing transmission within the domestic population from incursions across the wildlife–domestic interface, a common challenge in veterinary epidemiology. Spatiotemporal reconstruction of the epidemic reveals a highly skewed distribution of virus movements with a high proportion of shorter distance local movements interspersed with occasional long‐distance dispersal events associated with wild birds. We also show how such inference be used to identify possible instances of human‐mediated movements where distances between phylogenetically linked domestic cases are unusually high

GeoCREV: veterinary geographical information system and the development of a practical sub-national spatial data infrastructure

This paper illustrates and discusses the key issues of the geographical information system (GIS) developed by the Unit of Veterinary Epidemiology of the Veneto region (CREV), defined according to user needs, spatial data (availability, accessibility and applicability), development, technical aspects, inter-institutional relationships, constraints and policies. GeoCREV, the support system for decision-making, was designed to integrate geographic information and veterinary laboratory data with the main aim to develop a sub-national, spatial data infrastructure (SDI) for the veterinary services of the Veneto region in north-eastern Italy. Its implementation required (i) collection of data and information; (ii) building a geodatabase; and (iii) development of a WebGIS application. Tools for the management, collection, validation and dissemination of the results (public access and limited access) were developed. The modular concept facilitates the updating and development of the system according to user needs and data availability. The GIS management practices that were followed to develop the system are outlined, followed by a detailed discussion of the key elements of the GIS implementation process (data model, technical aspects, inter-institutional relationship, user dimension and institutional framework). Problems encountered in organising the non-spatial data and the future work directions are also described

Different environmental gradients associated to the spatiotemporal and genetic pattern of the H5N8 highly pathogenic avian influenza outbreaks in poultry in Italy

Comprehensive understanding of the patterns and drivers of avian influenza outbreaks is pivotal to inform surveillance systems and heighten nations’ ability to quickly detect and respond to the emergence of novel viruses. Starting in early 2017, the Italian poultry sector has been involved in the massive H5N8 highly pathogenic avian influenza epidemic that spread in the majority of the European countries in 2016/2017. Eighty‐three outbreaks were recorded in north‐eastern Italy, where a densely populated poultry area stretches along the Lombardy, Emilia‐Romagna and Veneto regions. The confirmed cases, affecting both the rural and industrial sectors, depicted two distinct epidemic waves. We adopted a combination of multivariate statistics techniques and multi‐model regression selection and inference, to investigate how environmental factors relate to the pattern of outbreaks diversity with respect to their spatiotemporal and genetic diversity. Results showed that a combination of eco‐climatic and host density predictors were associated with the outbreaks pattern, and variation along gradients was noticeable among genetically and geographically distinct groups of avian influenza cases. These regional contrasts may be indicative of a different mechanism driving the introduction and spreading routes of the influenza virus in the domestic poultry population. This methodological approach may be extended to different spatiotemporal scale to foster site‐specific, ecologically informed risk mitigating strategies

Impact of emergency oral rabies vaccination of foxes in northeastern Italy, 28 December 2009-20 January 2010: preliminary evaluation.

Fox rabies re-emerged in northeastern Italy in 2008, in an area bordering Slovenia. In 2009, the infection spread westward to Veneto region and in 2010 to the provinces of Trento and Bolzano. Aerial emergency oral fox vaccination was implemented in the winter 2009-10. Since this vaccination was performed at altitudes below the freezing level, a statistical analysis was conducted to evaluate its impact. Of the foxes sampled following the vaccination campaign, 77% showed a rabies antibody titre of ≥0.5 IU/ml

Epidemiology-driven approaches to surveillance in HPAI-vaccinated poultry flocks aiming to demonstrate freedom from circulating HPAIV

Incursion pressure of high pathogenicity avian influenza viruses (HPAIV) by secondary spread among poultry holdings and/or from infected migratory wild bird populations increases worldwide. Vaccination as an additional layer of protection of poultry holdings using appropriately matched vaccines aims at reducing clinical sequelae of HPAIV infection, disrupting HPAIV transmission, curtailing economic losses and animal welfare problems and cutting exposure risks of zoonotic HPAIV at the avian-human interface. Products derived from HPAIV-vaccinated poultry should not impose any risk of virus spread or exposure. Vaccination can be carried out with zero-tolerance for infection in vaccinated herds and must then be flanked by appropriate surveillance which requires tailoring at several levels: (i) Controlling appropriate vaccination coverage and adequate population immunity in individual flocks and across vaccinated populations; (ii) assessing HPAI-infection trends in unvaccinated and vaccinated parts of the poultry population to provide early detection of new/re-emerged HPAIV outbreaks; and (iii) proving absence of HPAIV circulation in vaccinated flocks ideally by real time-monitoring. Surveillance strategies, i.e. selecting targets, tools and random sample sizes, must be accommodated to the specific epidemiologic and socio-economic background. Methodological approaches and practical examples from three countries or territories applying AI vaccination under different circumstances are reviewed here

Modelling the impact of co-circulating low pathogenic avian influenza viruses on epidemics of highly pathogenic avian influenza in poultry

It is well known that highly pathogenic avian influenza (HPAI) viruses emerge through mutation of precursor low pathogenic avian influenza (LPAI) viruses in domestic poultry populations. The potential for immunological cross-protection between these pathogenic variants is recognised but the epidemiological impact during co-circulation is not well understood. Here we use mathematical models to investigate whether altered flock infection parameters consequent to primary LPAI infections can impact on the spread of HPAI at the population level. First we used mechanistic models reflecting the co-circulatory dynamics of LPAI and HPAI within a single commercial poultry flock. We found that primary infections with LPAI led to HPAI prevalence being maximised under a scenario of high but partial cross-protection. We then tested the population impact in spatially-explicit simulations motivated by a major avian influenza A(H7N1) epidemic that afflicted the Italian poultry industry in 1999-2001. We found that partial cross-protection can lead to a prolongation of HPAI epidemic duration. Our findings have implications for the control of HPAI in poultry particularly for settings in which LPAI and HPAI frequently co-circulate

Geographical information systems in the management of the 2009-2010 emergency oral anti-rabies vaccination of foxes in north-eastern Italy

Emergency oral fox vaccination campaigns, targeting a recent rabies epidemic in wild foxes (Vulpes vulpes) in north-eastern Italy, were implemented twice, first in the winter of 2009 and then in the spring of 2010. Following on an unsuccessful manual bait distribution campaign, vaccine baits were aerially distributed by helicopters using a satellite-navigated, computer-supported, automatic bait drop system. The flight paths were traced with distance of 500-1,000 m from one another to optimise helicopter missions and guarantee homogeneous coverage of the vaccination area. The vaccine distribution was evaluated by superimposing a 1 km-step grid and weighing the number of baits per cell. The implementation of a geographical information system for the management of vaccine distribution proved to be useful, both for the planning and execution phases, of the campaigns. It supported effective management of the flights and allowed near real-time monitoring of the campaigns. In addition, it facilitated the identification of areas with suboptimal bait density that would require additional flights or supplementary, manual distributio