Risk factors for avian influenza in Danish poultry and wild birds during the epidemic from June 2020 to May 2021
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ABSTRACT:
SUBMITTER: Liu Y
PROVIDER: S-EPMC10914952 | biostudies-literature | 2024 Jan
REPOSITORIES: biostudies-literature
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Project description:Avian influenza (AI) is a contagious disease of birds with zoonotic potential. AI virus (AIV) can infect most bird species, but clinical signs and mortality vary. Assessing the distribution and factors affecting AI presence can direct targeted surveillance to areas at risk of disease outbreaks, or help identify disease hotspots or areas with inadequate surveillance. Using virus surveillance data from passive and active AIV wild bird surveillance, 2006-2020, we investigated the association between the presence of AIV and a range of landscape factors and game bird release. Furthermore, we assessed potential bias in the passive AIV surveillance data submitted by the public, via factors related to public accessibility. Lastly, we tested the AIV data for possible hot- and cold spots within Denmark. The passive surveillance data was biased regarding accessibility to areas (distance to roads, cities and coast) compared to random locations within Denmark. For both the passive and active AIV surveillance data, we found significant (p < .01) associations with variables related to coast, wetlands and cities, but not game bird release. We used these variables to predict the risk of AIV presence throughout Denmark, and found high-risk areas concentrated along the coast and fjords. For both passive and active surveillance data, low-risk clusters were mainly seen in Jutland and northern Zealand, whereas high-risk clusters were found in Jutland, Zealand, Funen and the southern Isles such as Lolland and Falster. Our results suggest that landscape affects AIV presence, as coastal areas and wetlands attract waterfowl and migrating birds and therefore might increase the potential for AIV transmission. Our findings have enabled us to create risk maps of AIV presence in wild birds and pinpoint high-risk clusters within Denmark. This will aid targeted surveillance efforts within Denmark and potentially aid in planning the location of future poultry farms.
| S-EPMC9291307 | biostudies-literature
Project description:Highly pathogenic avian influenza (HPAI, Gs/Gd lineage) was introduced to Europe in 2005 and has since caused numerous outbreaks in birds. The 2020-2021 season was the hitherto most devastating when considering bird numbers and duration in Europe. Surveillance data, virologic results and epidemiologic investigations from the 2020-2021 outbreaks in Sweden were analysed. Subtypes H5N8 and H5N5 were detected on 24 farms with poultry or other captive birds. In wild birds, subtypes H5N8, H5N5, H5N1, H5N4, H5Nx were detected in 130 out of 811 sampled birds. There was a spatiotemporal association between cases in wild birds and poultry. Based on phylogeny and epidemiology, most of the introductions of HPAI to commercial poultry were likely a result of indirect contact with wild birds. A definite route of introduction to poultry could not be established although some biosecurity breaches were observed. No spread between farms was identified but airborne spread between flocks on the same farm was suspected. Our findings exemplify the challenges posed by the continuously changing influenza viruses that seem to adapt to a broader species spectrum. This points to the importance of wild bird surveillance, compliance to biosecurity, and identification of risk factors for introduction on poultry farms.
| S-EPMC9318561 | biostudies-literature
Project description:Highly pathogenic avian influenza (HPAI) viruses of subtype H5Nx caused outbreaks in poultry, captive birds, and wild birds in the Netherlands between October 2020 and June 2021. The full genome sequences of 143 viruses were analyzed. HPAI viruses were mainly of subtype H5N8, followed by H5N1, but also viruses of subtypes H5N3, H5N4, and H5N5 were detected. At least seven distinct genotypes were found, carrying closely related H5 segments belonging to clade 2.3.4.4b. Molecular clock analysis suggests that the reassortments of the NA gene segments likely occurred before the introduction of these viruses into the Netherlands. Genetic analysis suggested that multiple independent introductions of HPAI H5N8 viruses occurred in the Netherlands, likely followed by local spread resulting in at least two clusters of related viruses. The analysis provided evidence for independent introductions from wild birds at 10 poultry farms, whereas for two outbreaks transmission between farms could not be excluded. HPAI H5Nx viruses were detected in dead wild birds of 33 species, but mostly infected geese and swans were found. The pathogenicity of the H5N8 virus was determined for chickens and Pekin ducks, showing reduced mortality for ducks. This study provides more insight into the genetic diversity of HPAI H5Nx viruses generated by reassortment and evolution, and the spread of these viruses between wild birds and poultry. The fast and continuing evolution of H5 clade 2.3.4.4b may provide opportunities for these viruses to adapt to specific bird species, or possibly mammalian species and humans. IMPORTANCE Highly pathogenic avian influenza (HPAI) viruses are spread by migratory wild birds. Viruses causing outbreaks in wild birds and poultry in the Netherlands in 2020-2021 were genetically analyzed, which suggested that multiple virus incursions occurred. The outbreaks in poultry were likely caused by independent introductions from wild birds; only in one case virus spread between farms could not be excluded. Viruses of subtype H5N8 were mainly observed, but also other subtypes were detected that likely evolved by exchange of genetic information before these viruses were introduced into the Netherlands. Viruses were detected in many species of dead wild birds, but mostly in geese and swans. We showed that the H5N8 virus causes a higher mortality in chickens compared to ducks. This is consistent with the fact that not many wild ducks were found dead. This study provides more insight in the evolution and spread of HPAI viruses in wild birds and poultry.
| S-EPMC9045216 | biostudies-literature
Project description:BackgroundWild birds are the major reservoir hosts for influenza A viruses, occasionally transmitting to other species such as domesticated poultry. Despite an abundance of genomic data from avian influenza virus (AIV), little is known about whether AIV evolves differently in wild birds and poultry, although this is critical to revealing the dynamics and time-scale of viral evolution. In particular, because environmental (water-borne) transmission is more common in wild birds, which may reduce the number of replications per unit time, it is possible that evolutionary rates are systematically lower in wild birds than in poultry.ResultsWe estimated rates of nucleotide substitution in two AIV subtypes that are strongly associated with infections in wild birds - H4 and H6 - and compared these to rates in the H5N1 subtype that has circulated in poultry for almost two decades. Our analyses of three internal genes confirm that H4 and H6 viruses are evolving significantly more slowly than H5N1 viruses, suggesting that evolutionary rates of AIV are reduced in wild birds. This result was verified by the analysis of a poultry-associated H6 lineage that exhibited a markedly higher substitution rate than those H6 viruses circulating in wild birds. Interestingly, we also observed a significant difference in evolutionary rate between H4 and H6, despite frequent reassortment rate among them.ConclusionsAIV experiences markedly different evolutionary dynamics between wild birds and poultry. These results suggest that rate heterogeneity among viral subtypes and ecological groupings should be taken into account when estimating evolutionary rates and divergence times.
| S-EPMC4481119 | biostudies-literature
Project description:The number of highly pathogenic avian influenza (HPAI) H5-related infections and deaths of wild birds in Europe was high during October 1, 2020-September 30, 2022. To quantify deaths among wild species groups with known susceptibility for HPAI H5 during those epidemics, we collected and recorded mortality data of wild birds in the Netherlands. HPAI virus infection was reported in 51 bird species. The species with the highest numbers of reported dead and infected birds varied per epidemic year; in 2020-21, they were within the Anatidae family, in particular barnacle geese (Branta leucopsis) and in 2021-22, they were within the sea bird group, particularly Sandwich terns (Thalasseus sandvicensis) and northern gannet (Morus bassanus). Because of the difficulty of anticipating and modeling the future trends of HPAI among wild birds, we recommend monitoring live and dead wild birds as a tool for surveillance of the changing dynamics of HPAI.
| S-EPMC10756359 | biostudies-literature
Project description:Avian influenza viruses (AIV) are of great socioeconomic and health concern, notably in Southeast Asia where highly pathogenic strains, such as highly pathogenic avian influenza (HPAI) H5N1 and other H5 and H7 AIVs, continue to occur. Wild bird migrants are often implicated in the maintenance and spread of AIV. However, little systematic surveillance of wild birds has been conducted in Southeast Asia to evaluate whether the prevalence of AIV in wild birds is higher than in other parts of the world where HPAI outbreaks occur less frequently. Across Bangladesh, we randomly sampled a total of 3585 wild and domestic birds to assess the prevalence of AIV and antibodies against AIV and compared these with prevalence levels found in other endemic and non-endemic countries. Our study showed that both resident and migratory wild birds in Bangladesh do not have a particularly elevated AIV prevalence and AIV sero-prevalence compared to wild birds from regions in the world where H5N1 is not endemic and fewer AIV outbreaks in poultry occur. Like elsewhere, notably wild birds of the orders Anseriformes were identified as the main wild bird reservoir, although we found exceptionally high sero-prevalence in one representative of the order Passeriformes, the house crow (Corvus splendens), importantly living on offal from live bird markets. This finding, together with high sero- and viral prevalence levels of AIV in domestic birds, suggests that wild birds are not at the base of the perpetuation of AIV problems in the local poultry sector, but may easily become victim to AIV spill back from poultry into some species of wild birds, potentially assisting in further spread of the virus.
| S-EPMC5662684 | biostudies-literature
Project description:We identified highly pathogenic avian influenza A(H5N1) virus clade 2.3.4.4b in wild birds, poultry, and a lion in Peru during November 2022-February 2023 and markers associated with transmission adaptation and antiviral drug resistance. Continuous genomic surveillance is needed to inform public health measures and avoid mass animal deaths.
| S-EPMC10683826 | biostudies-literature
Project description:Highly pathogenic avian influenza (H5N1) among wild birds emerged simultaneously with outbreaks in domestic poultry in South Korea during November 2010-May 2011. Phylogenetic analysis showed that these viruses belonged to clade 2.3.2, as did viruses found in Mongolia, the People's Republic of China, and Russia in 2009 and 2010.
| S-EPMC3309593 | biostudies-literature
Project description:European Union (EU) Member States (MSs) are required to carry out surveillance for avian influenza (AI) in poultry and wild birds and notify the results to the responsible authority. In addition, Iceland, Norway, Switzerland and the United Kingdom (Northern Ireland) also implement ongoing surveillance programmes to monitor incursions of avian influenza viruses (AIVs) in poultry and wild birds. EFSA received a mandate from the European Commission to collate, validate, analyse and summarise the data resulting from these AI surveillance programmes in an annual report. The present report summarises the results of the surveillance activities carried out in MSs and the aforementioned countries in 2021. Overall, 24,290 poultry establishments (PEs) were sampled, of which 27 were seropositive for influenza A(H5) and 4 for A(H7) viruses. Seropositive PEs were found in 10 MSs and, as per previous years, the highest percentages of seropositive PEs were found in establishments raising waterfowl game birds and breeding geese. Out of these 31 seropositive PEs, 3 tested positive by polymerase chain reaction (PCR) for influenza A(H5) viruses: 1 for highly pathogenic avian influenza virus (HPAIV), 1 for low pathogenic avian influenza virus (LPAIV) and 1 with unknown virus pathogenicity. In addition, 16 countries reported PCR test results from 1,858 PEs which did not correspond to the follow-up testing of a positive serology event (e.g. in some PEs, PCR tests were used for screening). Sixty-five of these PEs in 10 MSs were found positive for AIVs. Apart from poultry, 31,382 wild birds were sampled, with 2,314 wild birds testing positive for HPAIVs by PCR. Twenty-two countries reported HPAIV-positive wild birds and most positive samples were identified as highly pathogenic avian influenza (HPAI) A(H5N8) virus. In addition, 328 wild birds tested positive for LPAIVs of the A(H5/H7) subtypes and 362 wild birds tested positive for non-A(H5/H7) subtype AIVs.
| S-EPMC9475399 | biostudies-literature
Project description:In 2020, Council Directive 2005/94/EC required EU Member States (MSs) to carry out surveillance for avian influenza (AI) in poultry and wild birds and notify the results to the responsible authority. Based on this, MSs, Iceland, Norway, Switzerland and the United Kingdom implemented ongoing surveillance programmes to monitor incursions of AI viruses in poultry and wild birds. EFSA received a mandate from the European Commission to collate, validate, analyse and summarise the data resulting from the avian influenza surveillance programmes in an annual report. This is the second such report produced using data directly submitted to EFSA by MSs. This report summarises the results of the surveillance activities carried out in poultry and wild birds in 2020. Overall, 24,768 poultry establishments (PEs) were sampled, of which 46 were seropositive for H5 virus strains and seven for H7 strains. Seropositive PEs were found in nine MSs (Belgium, Denmark, Finland, France, Italy, the Netherlands, Poland, Spain and Sweden) and the United Kingdom. As per previous years, the highest percentages of seropositive PEs were found in establishments raising waterfowl game birds and breeding geese. Out of the 53 PEs with positive serological tests for H5/H7, seven tested positive in polymerase chain reaction (PCR) or virology for H5/H7 virus strains: six for Low Pathogenic Avian Influenza (LPAI) and one for Highly Pathogenic Avian Influenza (HPAI). In addition, 13 countries also reported PCR results from 748 PEs which did not correspond to the follow-up testing of a positive serology event (e.g. in some PEs, PCR tests were used for screening). Twenty-five of these PEs were found positive for AI viral RNA. These positive PEs were located in Bulgaria, Estonia, Germany, Romania and Slovakia. A total of 18,968 wild birds were sampled, with 878 birds testing positive to HPAI virus. Fourteen countries reported HPAI-positive wild birds, with all HPAI strains identified as H5. Most positive birds were infected with H5N8, with a smaller number of N1, N3, N5 and unidentified NA subtypes. In addition, there were 317 birds testing positive for LPAI H5 or H7 virus and 429 birds testing positive for non-H5/H7 AI virus, reported by 31 countries. The surveillance findings for poultry and wild birds for 2020 are discussed in relation to the current knowledge of the epidemiology of AI in Europe, in particular the H5N8 epidemic which has been identified late 2020.
| S-EPMC8647014 | biostudies-literature