Epidemiology and control of low pathogenicity avian influenza infections in rural poultry in Italy.
ABSTRACT We analyzed the involvement of the rural poultry sector in outbreaks of low pathogenicity avian influenza (AI) in Italy in 2007-2009 and discuss possible measures for improving monitoring and control. A description of how the rural poultry sector is organized also is provided. Data were obtained by the AI surveillance system established in the areas affected by the outbreaks. The surveillance activities identified two H7N3 epidemics, in 2007 and 2009, both of which mainly involved the rural sector, yet these activities did not allow for the prompt eradication of the disease. Additional strategies could be adopted to avoid the persistence of AI within the rural sector, based on the regulation and control of poultry holdings at the top of the production chain.
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ABSTRACT: Italy has experienced recurrent incursions of H5N2 avian influenza (AI) viruses in different geographical areas and varying sectors of the domestic poultry industry. Considering outbreak heterogeneity rather than treating all outbreaks of low pathogenicity AI (LPAI) viruses equally is important given their interactions with the environment and potential to spread, evolve and increase pathogenicity. This study aims at identifying potential environmental drivers of H5N2 LPAI outbreak occurrence in time, space and poultry populations. Thirty-four environmental variables were tested for association with the characteristics of 27 H5N2 LPAI outbreaks (i.e. time, place, flock type, number and species of birds affected) occurred among domestic poultry flocks in Italy in 2010-2012. This was done by applying a recently proposed analytical approach based on a combined non-metric multidimensional scaling, clustering and regression analysis. Results indicated that the pattern of (dis)similarities among the outbreaks entailed an underlying structure that may be the outcome of large-scale, environmental interactions in ecological dimension. Increased densities of poultry breeders, and increased land coverage by industrial, commercial and transport units were associated with increased heterogeneity in outbreak characteristics. In areas with high breeder densities and with many infrastructures, outbreaks affected mainly industrial turkey/layer flocks. Outbreaks affecting ornamental, commercial and rural multi-species flocks occurred mainly in lowly infrastructured areas of northern Italy. Outbreaks affecting rural layer flocks occurred mainly in areas with low breeder densities in south-central Italy. In savannah-like environments, outbreaks affected mainly commercial flocks of galliformes. Suggestive evidence that ecological ordination makes sense genetically was also provided, as virus strains showing high genetic similarity clustered into ecologically similar outbreaks. Findings were informed by hypotheses about how ecological interactions among poultry populations, viruses and their environments can be related to the observed patterns of H5N2 LPAI occurrence. This may prove useful in enhancing future interventions by developing site-specific, ecologically-grounded strategies.PLoS ONE 01/2014; 9(1):e86788. · 3.53 Impact Factor
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ABSTRACT: Backyard poultry farms infected with highly pathogenic avian influenza (HPAI) H5N1 virus in Nigeria between 2006 and 2008 were investigated for morbidity, mortality and Pathology. Affected farms raised local chickens, duck, turkey, guinea fowl and geese and were already confirmed to be infected with HPAI virus by virus isolation and reverse transcriptase polymerase chain reaction at the National Veterinary Research Institute, Vom Nigeria. Backyard local chickens recorded the highest number of death with 89.4% of the total flock size while the duck had the highest mortality rate at 87.1%. Mortality rate was least in guinea fowls (20.55%), and above average in geese (54.64%). For Pathology, submitted carcasses comprised of sixty (60) chickens, twenty-nine (29) ducks, thirty-seven (37) turkeys, fourteen (14) guinea fowls and twelve (12) geese which were examined for gross morphological changes and histopathology. Though lesions sparingly occurred in these village poultry, main pathologic findings were associated with the nervous, circulatory, respiratory, and gastro-intestinal systems and occasionally lesions were general unspecific and multi-systemic. It was observed that mortality rate was highest in duck, then chicken and turkey compared to guinea fowl and geese while lesions were milder and mortality were acute in these flocks. Key words: backyard poultry, morbidity, mortality, pathologyIOSR Journal of Agriculture and Veterinary Science (IOSR-JAVS). 09/2014; Volume 7(Volume 7, Issue 9 Ver. II (Sep. 2014)):PP 23-27.
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ABSTRACT: SUMMARY Transmission experiments are useful for investigating the mechanisms of low pathogenic notifiable avian influenza virus (LPNAI) transmission. In this study, the hypothesis that inoculation-infected chickens are more infectious than contact-infected chickens was tested. To this end, extended transmission experiments with one H5N2 and one H7N1 LPAIV which had previously been characterized in a series of standard transmission experiments were conducted in specific pathogen-free (SPF) chickens. For the H5N2 LPAIV, the infectivity of contact-infected chickens was similar to the infectivity of inoculated chickens. Despite results from a previous study suggesting the H7N1 LPAIV strain to be similarly infectious to SPF chickens as the H5N2 LPAIV strain, the acquisition of contact-infected chickens proved more difficult for H7N1 LPAIV. It was assumed that this might have been a consequence of the length and timing of the exposure period. In conclusion, for LPNAIVs that first seemed equally infectious, short-term transmissibility may vary considerably.Epidemiology and infection. 06/2014;