RESUMO
OBJECTIVE: Unprecedented SARS-CoV-2 infections in farmed minks raised immediate concerns regarding transmission to humans and initiated intensive environmental investigations to assess occupational and environmental exposure. METHODS: Air sampling was performed at infected Dutch mink farms, at farm premises and at nearby residential sites. A range of other environmental samples were collected from minks' housing units, including bedding materials. SARS-CoV-2 RNA was analysed in all samples by quantitative PCR. RESULTS: Inside the farms, considerable levels of SARS-CoV-2 RNA were found in airborne dust, especially in personal inhalable dust samples (approximately 1000-10 000 copies/m3). Most of the settling dust samples tested positive for SARS-CoV-2 RNA (82%, 75 of 92). SARS-CoV-2 RNA was not detected in outdoor air samples, except for those collected near the entrance of the most recently infected farm. Many samples of minks' housing units and surfaces contained SARS-CoV-2 RNA. CONCLUSIONS: Infected mink farms can be highly contaminated with SARS-CoV-2 RNA. This warns of occupational exposure, which was substantiated by considerable SARS-CoV-2 RNA concentrations in personal air samples. Dispersion of SARS-CoV-2 to outdoor air was found to be limited and SARS-CoV-2 RNA was not detected in air samples collected beyond farm premises, implying a negligible risk of environmental exposure to nearby communities. Our occupational and environmental risk assessment is in line with whole genome sequencing analyses showing mink-to-human transmission among farm workers, but no indications of direct zoonotic transmission events to nearby communities.
Assuntos
Poeira/análise , Exposição Ambiental , Fazendas , Vison/virologia , Exposição Ocupacional , RNA Viral/isolamento & purificação , SARS-CoV-2/isolamento & purificação , Animais , Humanos , Países Baixos/epidemiologiaRESUMO
No recent information is available on the specificity of current M. synoviae (Ms) and M. gallisepticum (Mg) serological tests. In this study the performance of a currently available Mg and Ms Rapid Plate Agglutination (RPA) test, and three Mg, three Ms and three Mg/Ms combination ELISAs were evaluated on SPF sera that were obtained from days (D) 0-28 after M. gallinarum, M. imitans or M. gallinaceum inoculation, after sham inoculation and without inoculation. Tracheal swabs for mycoplasma culture were obtained before inoculation (D0), 7 and 28 days post inoculation (d.p.i.) in all groups except the sham inoculated group. The different mycoplasma species colonized well. In the early stage after inoculation (7-14 d.p.i.) with heterologous mycoplasma species, the specificity varied from 85% to 100% in the Mg RPA test and from 70% to 85% in the Ms RPA test. The specificity of both Mg and Ms RPA test was 100% in the sham inoculated samples and ruled out the effect of sham medium. In the late stage (21-28 d.p.i.) specificity was 100% for both RPA tests. The test specificity was 100% for seven ELISAs except for two combination ELISAs where a specificity of 95% was found in the late stage after inoculation. However, this was not significantly different from the specificity of all other tests in the late stage of these groups. These results show that it is not advisable to establish Mg and Ms seromonitoring programmes on the Mg and Ms RPA test alone as other mycoplasma species frequently occur in poultry.
Assuntos
Galinhas , Infecções por Mycoplasma/veterinária , Mycoplasma gallisepticum/isolamento & purificação , Mycoplasma synoviae/isolamento & purificação , Doenças das Aves Domésticas/microbiologia , Testes Sorológicos/veterinária , Animais , Reações Falso-Positivas , Infecções por Mycoplasma/diagnóstico , Infecções por Mycoplasma/microbiologia , Mycoplasma gallisepticum/genética , Mycoplasma synoviae/genética , Doenças das Aves Domésticas/diagnóstico , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Especificidade da Espécie , Organismos Livres de Patógenos EspecíficosRESUMO
SARS-CoV-2, the causative agent of COVID-19, caused respiratory disease outbreaks with increased mortality in 4 mink farms in the Netherlands. The most striking postmortem finding was an acute interstitial pneumonia, which was found in nearly all examined mink that died at the peak of the outbreaks. Acute alveolar damage was a consistent histopathological finding in mink that died with pneumonia. SARS-CoV-2 infections were confirmed by detection of viral RNA in throat swabs and by immunohistochemical detection of viral antigen in nasal conchae, trachea, and lung. Clinically, the outbreaks lasted for about 4 weeks but some animals were still polymerase chain reaction-positive for SARS-CoV-2 in throat swabs after clinical signs had disappeared. This is the first report of the clinical and pathological characteristics of SARS-CoV-2 outbreaks in mink farms.
Assuntos
Betacoronavirus , Infecções por Coronavirus/veterinária , Vison/virologia , Pandemias/veterinária , Pneumonia Viral/veterinária , Animais , COVID-19 , Infecções por Coronavirus/patologia , Surtos de Doenças/veterinária , Feminino , Pulmão/patologia , Pulmão/virologia , Masculino , Países Baixos/epidemiologia , Pneumonia Viral/patologia , SARS-CoV-2RESUMO
Respiratory disease and increased mortality occurred in minks on two farms in the Netherlands, with interstitial pneumonia and SARS-CoV-2 RNA in organ and swab samples. On both farms, at least one worker had coronavirus disease-associated symptoms before the outbreak. Variations in mink-derived viral genomes showed between-mink transmission and no infection link between the farms. Inhalable dust contained viral RNA, indicating possible exposure of workers. One worker is assumed to have attracted the virus from mink.
Assuntos
Infecções por Coronavirus/diagnóstico , Coronavirus/isolamento & purificação , Surtos de Doenças/prevenção & controle , Fazendas , Vison , Pneumonia Viral/diagnóstico , RNA Viral/genética , Análise de Sequência de RNA/veterinária , Animais , Anticorpos Antivirais/imunologia , Betacoronavirus/imunologia , COVID-19 , Coronavirus/genética , Infecções por Coronavirus/transmissão , Infecções por Coronavirus/veterinária , Surtos de Doenças/veterinária , Genoma Viral , Países Baixos , Pandemias/veterinária , Pneumonia Viral/transmissão , Pneumonia Viral/veterinária , SARS-CoV-2 , Síndrome Respiratória Aguda Grave/epidemiologiaRESUMO
This study reports the results of diagnostic and molecular typing methods for 18 Avibacterium paragallinarum isolates obtained from outbreaks of infectious coryza in commercial layer flocks in the Netherlands. Isolation, biochemical identification, species-specific PCR tests and classical serotyping were performed. In addition, molecular typing by Enterobacterial Repetitive Intergenic Consensus-Based Polymerase Chain Reaction (ERIC-PCR) and sequence analysis of the partial HPG2 region of A. paragallinarum were applied and results of both techniques were compared. Moreover, the pathogenicity of an isolate of the most common genotype detected in the Netherlands was determined in an animal experiment. All 18 Avibacterium isolates were nicotinamide adenine dinucleotide-dependent. All isolates were detected by the species-specific conventional PCR while 33% of the isolates were missed by the species-specific real-time PCR. Sequence analysis showed a probe mismatch as a result of a single nucleotide polymorphism (G1516A). Modification of the probe of the real-time PCR was necessary to overcome false negative results. Molecular typing showed that sequence analysis of the partial HPG2 region was in concordance with ERIC-PCR results and indicated the presence of two major genotypes. Serotyping showed the presence of serovars A-1, A-2 and B-1. There was no correlation between genotyping results and serotyping results. Inoculation of an isolate of the most prevalent genotype, and belonging to serovar A-1, into brown layer hens demonstrated the pathogenicity of this isolate.
Assuntos
Galinhas/microbiologia , Enterobacteriaceae/genética , Infecções por Pasteurellaceae/veterinária , Pasteurellaceae/genética , Doenças das Aves Domésticas/microbiologia , Animais , Surtos de Doenças/veterinária , Enterobacteriaceae/isolamento & purificação , Feminino , Tipagem Molecular/veterinária , Países Baixos/epidemiologia , Pasteurellaceae/isolamento & purificação , Pasteurellaceae/patogenicidade , Infecções por Pasteurellaceae/epidemiologia , Infecções por Pasteurellaceae/microbiologia , Reação em Cadeia da Polimerase/veterinária , Doenças das Aves Domésticas/diagnóstico , Doenças das Aves Domésticas/epidemiologia , Sorogrupo , Sorotipagem/veterinária , Especificidade da Espécie , VirulênciaRESUMO
Using annual serologic surveillance data from all poultry farms in the Netherlands during 2007-2013, we quantified the risk for the introduction of low pathogenicity avian influenza virus (LPAIV) in different types of poultry production farms and putative spatial-environmental risk factors: distance from poultry farms to clay soil, waterways, and wild waterfowl areas. Outdoor-layer, turkey (meat and breeder), and duck (meat and breeder) farms had a significantly higher risk for LPAIV introduction than did indoor-layer farms. Except for outdoor-layer, all poultry types (i.e., broilers, chicken breeders, ducks, and turkeys) are kept indoors. For all production types, LPAIV risk decreased significantly with increasing distance to medium-sized waterways and with increasing distance to areas with defined wild waterfowl, but only for outdoor-layer and turkey farms. Future research should focus not only on production types but also on distance to waterways and wild bird areas. In addition, settlement of new poultry farms in high-risk areas should be discouraged.
Assuntos
Surtos de Doenças , Virus da Influenza A Subtipo H5N1/genética , Vírus da Influenza A Subtipo H7N1/genética , Vírus da Influenza A/classificação , Influenza Aviária/epidemiologia , Carne/virologia , Doenças das Aves Domésticas/epidemiologia , Animais , Animais Selvagens/virologia , Galinhas , Patos , Monitoramento Epidemiológico , Fazendas/organização & administração , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Virus da Influenza A Subtipo H5N1/patogenicidade , Vírus da Influenza A Subtipo H7N1/isolamento & purificação , Vírus da Influenza A Subtipo H7N1/patogenicidade , Vírus da Influenza A/genética , Vírus da Influenza A/isolamento & purificação , Vírus da Influenza A/patogenicidade , Influenza Aviária/virologia , Países Baixos/epidemiologia , Aves Domésticas , Doenças das Aves Domésticas/virologia , Risco , Perus , VirulênciaRESUMO
Introduction of highly pathogenic avian influenza (HPAI) virus A(H5N8) into Europe prompted animal and human health experts to implement protective measures to prevent transmission to humans. We describe the situation in 2016 and list public health measures and recommendations in place. We summarise critical interfaces identified during the A(H5N1) and A(H5N8) outbreaks in 2014/15. Rapid exchange of information between the animal and human health sectors is critical for a timely, effective and efficient response.
Assuntos
Surtos de Doenças/prevenção & controle , Vírus da Influenza A Subtipo H5N8/isolamento & purificação , Vírus da Influenza A Subtipo H5N8/patogenicidade , Influenza Aviária/virologia , Influenza Humana/virologia , Zoonoses/prevenção & controle , Animais , Aves , Europa (Continente)/epidemiologia , Humanos , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Virus da Influenza A Subtipo H5N1/patogenicidade , Influenza Aviária/epidemiologia , Influenza Aviária/transmissão , Influenza Humana/epidemiologia , Influenza Humana/transmissão , Vigilância da População , Aves Domésticas , Doenças das Aves Domésticas/epidemiologia , Saúde Pública , Virulência , Zoonoses/transmissão , Zoonoses/virologiaRESUMO
Genetic analyses of highly pathogenic avian influenza A(H5N8) virus from the Netherlands, and comparison with strains from Europe, South Korea, and Japan, showed a close relation. Data suggest the strains were probably carried to the Netherlands by migratory wild birds from Asia, possibly through overlapping flyways and common breeding sites in Siberia.
Assuntos
Genoma Viral , Vírus da Influenza A/classificação , Vírus da Influenza A/genética , Influenza Aviária/epidemiologia , Influenza Aviária/virologia , Aves Domésticas , Animais , Animais Selvagens , Ásia/epidemiologia , Surtos de Doenças , História do Século XXI , Influenza Aviária/história , Países Baixos/epidemiologia , Filogenia , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/virologia , RNA Viral , Análise de Sequência de DNARESUMO
The emergence of Schmallenberg virus (SBV), a novel orthobunyavirus, in ruminants in Europe triggered a joint veterinary and public health response to address the possible consequences to human health. Use of a risk profiling algorithm enabled the conclusion that the risk for zoonotic transmission of SBV could not be excluded completely. Self-reported health problems were monitored, and a serologic study was initiated among persons living and/or working on SBV-affected farms. In the study set-up, we addressed the vector and direct transmission routes for putative zoonotic transfer. In total, 69 sheep farms, 4 goat farms, and 50 cattle farms were included. No evidence for SBV-neutralizing antibodies was found in serum of 301 participants. The lack of evidence for zoonotic transmission from either syndromic illness monitoring or serologic testing of presumably highly exposed persons suggests that the public health risk for SBV, given the current situation, is absent or extremely low.
Assuntos
Infecções por Bunyaviridae/transmissão , Doenças Transmissíveis Emergentes/transmissão , Orthobunyavirus/isolamento & purificação , Zoonoses/transmissão , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Infecções por Bunyaviridae/epidemiologia , Infecções por Bunyaviridae/veterinária , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/transmissão , Doenças Transmissíveis Emergentes/epidemiologia , Europa (Continente)/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Orthobunyavirus/classificação , Vigilância da População , Risco , Ruminantes , Estudos Soroepidemiológicos , Adulto Jovem , Zoonoses/epidemiologiaRESUMO
Infections with Schmallenberg virus (SBV) are associated with congenital malformations in ruminants. Because reporting of suspected cases only could underestimate the true rate of infection, we conducted a seroprevalence study in the Netherlands to detect past exposure to SBV among dairy cattle. A total of 1,123 serum samples collected from cattle during November 2011-January 2012 were tested for antibodies against SBV by using a virus neutralization test; seroprevalence was 72.5%. Seroprevalence was significantly higher in the central-eastern part of the Netherlands than in the northern and southern regions (p<0.001). In addition, high (70%-100%) within-herd seroprevalence was observed in 2 SBV-infected dairy herds and 2 SBV-infected sheep herds. No significant differences were found in age-specific prevalence of antibodies against SBV, which is an indication that SBV is newly arrived in the country.
Assuntos
Anticorpos Antivirais/sangue , Infecções por Bunyaviridae/veterinária , Doenças dos Bovinos/epidemiologia , Doenças Transmissíveis Emergentes/veterinária , Orthobunyavirus/imunologia , Animais , Infecções por Bunyaviridae/epidemiologia , Infecções por Bunyaviridae/virologia , Bovinos , Doenças dos Bovinos/virologia , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/virologia , Indústria de Laticínios , Países Baixos/epidemiologia , Estações do Ano , Estudos SoroepidemiológicosRESUMO
Poultry can become infected with avian influenza viruses (AIV) via (in) direct contact with infected wild birds. Free-range chicken farms in the Netherlands were shown to have a higher risk for introduction of low pathogenic avian influenza (LPAI) virus than indoor chicken farms. Therefore, during outbreaks of highly pathogenic avian influenza (HPAI), free-range layers are confined indoors as a risk mitigation measure. In this study, we characterized the seasonal patterns of AIV introductions into free-range layer farms, to determine the high-risk period. Data from the LPAI serological surveillance programme for the period 2013-2016 were used to first estimate the time of virus introduction into affected farms and then assess seasonal patterns in the risk of introduction. Time of introduction was estimated by fitting a mathematical model to seroprevalence data collected longitudinally from infected farms. For the period 2015-2016, longitudinal follow-up included monthly collections of eggs for serological testing from a cohort of 261 farms. Information on the time of introduction was then used to estimate the monthly incidence and seasonality by fitting harmonic and Poisson regression models. A significant yearly seasonal risk of introduction that lasted around 4 months (November to February) was identified with the highest risk observed in January. The risk for introduction of LPAI viruses in this period was on average four times significantly higher than the period of low risk around the summer months. Although the data for HPAI infections were limited in the period 2014-2018, a similar risk period for introduction of HPAI viruses was observed. The results of this study can be used to optimize risk-based surveillance and inform decisions on timing and duration of indoor confinement when HPAI viruses are known to circulate in the wild bird population.
Assuntos
Galinhas , Fazendas , Vírus da Influenza A/fisiologia , Influenza Aviária/epidemiologia , Doenças das Aves Domésticas/epidemiologia , Animais , Surtos de Doenças/veterinária , Influenza Aviária/virologia , Países Baixos/epidemiologia , Óvulo/virologia , Doenças das Aves Domésticas/virologia , Prevalência , Fatores de Risco , Estações do Ano , Estudos SoroepidemiológicosRESUMO
In recent years, different subtypes of highly pathogenic avian influenza (HPAI) viruses caused outbreaks in several poultry types worldwide. Early detection of HPAI virus infection is crucial to reduce virus spread. Previously, the use of a mortality ratio threshold to expedite notification of suspicion in layer farms was proposed. The purpose of this study was to describe the clinical signs reported in the early stages of HPAI H5N8 and H5N6 outbreaks on chicken and Pekin duck farms between 2014 and 2018 in the Netherlands and compare them with the onset of an increased mortality ratio (MR). Data on daily mortality and clinical signs from nine egg-producing chicken farms and seven Pekin duck farms infected with HPAI H5N8 (2014 and 2016) and H5N6 (2017-2018) in the Netherlands were analysed. In 12 out of 15 outbreaks for which a MR was available, MR increase preceded or coincided with the first observation of clinical signs by the farmer. In one chicken and two Pekin duck outbreaks, clinical signs were observed prior to MR increase. On all farms, veterinarians observed clinical signs of general disease. Nervous or locomotor signs were reported in all Pekin duck outbreaks, but only in two chicken outbreaks. Other clinical signs were observed less frequently in both chickens and Pekin ducks. Compared to veterinarians, farmers observed and reported clinical signs, especially respiratory and gastrointestinal signs, less frequently. This case series suggests that a MR with a set threshold could be an objective parameter to detect HPAI infection on chicken and Pekin duck farms at an early stage. Observation of clinical signs may provide additional indication for farmers and veterinarians for notifying a clinical suspicion of HPAI infection. Further assessment and validation of a MR threshold in Pekin ducks are important as it could serve as an important tool in HPAI surveillance programs.
Assuntos
Galinhas , Surtos de Doenças/veterinária , Patos , Vírus da Influenza A/fisiologia , Influenza Aviária/epidemiologia , Doenças das Aves Domésticas/epidemiologia , Animais , Vírus da Influenza A Subtipo H5N8/fisiologia , Vírus da Influenza A/classificação , Influenza Aviária/virologia , Países Baixos/epidemiologia , Doenças das Aves Domésticas/virologiaRESUMO
Animal experiments have shown that nonhuman primates, cats, ferrets, hamsters, rabbits, and bats can be infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In addition, SARS-CoV-2 RNA has been detected in felids, mink, and dogs in the field. Here, we describe an in-depth investigation using whole-genome sequencing of outbreaks on 16 mink farms and the humans living or working on these farms. We conclude that the virus was initially introduced by humans and has since evolved, most likely reflecting widespread circulation among mink in the beginning of the infection period, several weeks before detection. Despite enhanced biosecurity, early warning surveillance, and immediate culling of animals in affected farms, transmission occurred between mink farms in three large transmission clusters with unknown modes of transmission. Of the tested mink farm residents, employees, and/or individuals with whom they had been in contact, 68% had evidence of SARS-CoV-2 infection. Individuals for which whole genomes were available were shown to have been infected with strains with an animal sequence signature, providing evidence of animal-to-human transmission of SARS-CoV-2 within mink farms.
Assuntos
COVID-19/transmissão , COVID-19/virologia , Vison , SARS-CoV-2/genética , SARS-CoV-2/isolamento & purificação , Zoonoses , Animais , COVID-19/epidemiologia , COVID-19/veterinária , Surtos de Doenças , Fazendas , Humanos , Funções Verossimilhança , Mutação , Países Baixos/epidemiologia , Filogenia , RNA Viral/análise , RNA Viral/genética , SARS-CoV-2/classificação , SARS-CoV-2/fisiologia , Sequenciamento Completo do Genoma , Zoonoses/transmissão , Zoonoses/virologiaRESUMO
Associations between animal health and performance, and the host's microbiota have been recently established. In poultry, changes in the intestinal microbiota have been linked to housing conditions and host development, but how the intestinal microbiota respond to environmental changes under farm conditions is less well understood. To gain insight into the microbial responses following a change in the host's immediate environment, we monitored four indoor flocks of adult laying chickens three times over 16 weeks, during which two flocks were given access to an outdoor range, and two were kept indoors. To assess changes in the chickens' microbiota over time, we collected cloacal swabs of 10 hens per flock and performed 16S rRNA gene amplicon sequencing. The poultry house (i.e., the stable in which flocks were housed) and sampling time explained 9.2 and 4.4% of the variation in the microbial community composition of the flocks, respectively. Remarkably, access to an outdoor range had no detectable effect on microbial community composition, the variability of microbiota among chickens of the same flock, or microbiota richness, but the microbiota of outdoor flocks became more even over time. Fluctuations in the composition of the microbiota over time within each poultry house were mainly driven by turnover in rare, rather than dominant, taxa and were unique for each flock. We identified 16 amplicon sequence variants that were differentially abundant over time between indoor and outdoor housed chickens, however none were consistently higher or lower across all chickens of one housing type over time. Our study shows that cloacal microbiota community composition in adult layers is stable following a sudden change in environment, and that temporal fluctuations are unique to each flock. By exploring microbiota of adult poultry flocks within commercial settings, our study sheds light on how the chickens' immediate environment affects the microbiota composition.
RESUMO
BACKGROUND: Laying hens with access to outdoor ranges are exposed to additional environmental factors and microorganisms, including potential pathogens. Differences in composition of the cloacal microbial community between indoor- and outdoor-housed layers may serve as an indicator for exposure to the outdoor environment, including its pathogens, and may yield insights into factors affecting the chickens' microbiota community dynamics. However, little is known about the influence of outdoor housing on microbiota community composition in commercial layer flocks. We performed a cross-sectional field study to evaluate differences in the cloacal microbiota of indoor- vs outdoor-layers across farms. Eight layer flocks (four indoor, four outdoor) from five commercial poultry farms were sampled. Indoor and outdoor flocks with the same rearing flock of origin, age, and breed were selected. In each flock, cloacal swabs were taken from ten layers, and microbiota were analysed with 16S rRNA gene amplicon sequencing. RESULTS: Housing type (indoor vs outdoor), rearing farm, farm and poultry house within the farm all significantly contributed to bacterial community composition. Poultry house explained most of the variation (20.9%), while housing type only explained 0.2% of the variation in community composition. Bacterial diversity was higher in indoor-layers than in outdoor-layers, and indoor-layers also had more variation in their bacterial community composition. No phyla or genera were found to be differentially abundant between indoor and outdoor poultry houses. One amplicon sequence variant was exclusively present in outdoor-layers across all outdoor poultry houses, and was identified as Dietzia maris. CONCLUSIONS: This study shows that exposure to an outdoor environment is responsible for a relatively small proportion of the community variation in the microbiota of layers. The poultry house, farm, and rearing flock play a much greater role in determining the cloacal microbiota composition of adult laying hens. Overall, measuring differences in cloacal microbiota of layers as an indicator for the level of exposure to potential pathogens and biosecurity seems of limited practical use. To gain more insight into environmental drivers of the gut microbiota, future research should aim at investigating community composition of commercial layer flocks over time.
RESUMO
Poultry can become infected with low pathogenic avian influenza (LPAI) viruses via (in)direct contact with infected wild birds or by transmission of the virus between farms. This study combines routinely collected surveillance data with genetic analysis to assess the contribution of between-farm transmission to the overall incidence of LPAI virus infections in poultry. Over a 10-year surveillance period, we identified 35 potential cases of between-farm transmission in the Netherlands, of which 10 formed geographical clusters. A total of 21 LPAI viruses were isolated from nine potential between-farm transmission cases, which were further studied by genetic and epidemiological analysis. Whole genome sequence analysis identified close genetic links between infected farms in seven cases. The presence of identical deletions in the neuraminidase stalk region and minority variants provided additional indications of between-farm transmission. Spatiotemporal analysis demonstrated that genetically closely related viruses were detected within a median time interval of 8 days, and the median distance between the infected farms was significantly shorter compared to farms infected with genetically distinct viruses (6.3 versus 69.0 km; p < 0.05). The results further suggest that between-farm transmission was not restricted to holdings of the same poultry type and not related to the housing system. Although separate introductions from the wild bird reservoir cannot be excluded, our study indicates that between-farm transmission occurred in seven of nine virologically analysed cases. Based on these findings, it is likely that between-farm transmission contributes considerably to the incidence of LPAI virus infections in poultry.
Assuntos
Galinhas , Patos , Vírus da Influenza A/fisiologia , Influenza Aviária/epidemiologia , Doenças das Aves Domésticas/epidemiologia , Perus , Criação de Animais Domésticos , Animais , Monitoramento Epidemiológico , Fazendas , Feminino , Incidência , Influenza Aviária/transmissão , Influenza Aviária/virologia , Países Baixos/epidemiologia , Doenças das Aves Domésticas/transmissão , Doenças das Aves Domésticas/virologiaRESUMO
Analysis of low pathogenic avian influenza (LPAI) viruses circulating in the Netherlands in a previous study revealed associations of specific hemagglutinin (HA) and neuraminidase (NA) subtypes with wild bird or poultry hosts. In this study, we identified putative host associations in LPAI virus internal proteins. We show that LPAI viruses isolated from poultry more frequently carried the allele A variant of the nonstructural protein (NS) gene, compared to wild bird viruses. We determined the susceptibility of chickens to wild bird-associated subtypes H3N8 and H4N6 and poultry-associated subtypes H8N4 and H9N2, carrying either NS allele A or B, in an infection experiment. We observed variations in virus shedding and replication patterns, however, these did not correlate with the predicted wild bird- or poultry-associations of the viruses. The experiment demonstrated that LPAI viruses of wild bird-associated subtypes can replicate in chickens after experimental infection, despite their infrequent detection in poultry. Although the NS1 protein is known to play a role in immune modulation, no differences were detected in the limited innate immune response to LPAI virus infection. This study contributes to a better understanding of the infection dynamics of LPAI viruses in chickens.
Assuntos
Aves/virologia , Suscetibilidade a Doenças/veterinária , Influenza Aviária/transmissão , Aves Domésticas/virologia , Animais , Animais Selvagens/virologia , Suscetibilidade a Doenças/virologia , Genes Virais , Imunidade Inata/genética , Vírus da Influenza A Subtipo H3N8 , Vírus da Influenza A Subtipo H9N2 , Vírus da Influenza A , Influenza Aviária/virologia , Doenças das Aves Domésticas/virologia , Proteínas não Estruturais Virais/genética , Replicação Viral , Eliminação de Partículas ViraisRESUMO
Interspecies transmission of fecal microbiota can serve as an indicator for (indirect) contact between domestic and wild animals to assess risks of pathogen transmission, e.g., avian influenza. Here, we investigated whether oral inoculation of laying hens with feces of wild ducks (mallards, Anas platyrhynchos) resulted in a hen fecal microbiome that was detectably altered on community parameters or relative abundances of individual genera. To distinguish between effects of the duck inoculum and effects of the inoculation procedure, we compared the fecal microbiomes of adult laying hens resulting from 3 treatments: inoculation with wild duck feces (duck), inoculation with chicken feces (auto), and a negative control group with no treatment. We collected cloacal swabs from 7 hens per treatment before (day 0), and 2 and 7 D after inoculation, and performed 16S rRNA amplicon sequencing. No distinguishable effect of inoculation with duck feces on microbiome community (alpha and beta diversity) was found compared to auto or control treatments. At the individual taxonomic level, the relative abundance of the genus Alistipes (phylum Bacteroidetes) was significantly higher in the inoculated treatments (auto and duck) compared to the control 2 D after inoculation. Seven days after inoculation, the relative abundance of Alistipes had increased in the control and no effect was found anymore across treatments. These effects might be explained by the perturbation of the hen's microbiome caused by the inoculation procedure itself, or by intrinsic temporal variation in the hen's microbiome. This experiment shows that a single inoculation of fecal microbiota from duck feces to laying hens did not cause a measurable alteration of the gut microbiome community. Furthermore, the temporary change in relative abundance for Alistipes could not be attributed to the duck feces inoculation. These outcomes suggest that the fecal microbiome of adult laying hens may not be a useful indicator for detection of single oral exposure to wild duck feces.
Assuntos
Galinhas/microbiologia , Patos/microbiologia , Fezes/microbiologia , Microbiota , Vacinação/veterinária , Animais , Animais Selvagens/microbiologia , Feminino , RNA Ribossômico 16S/análiseRESUMO
In this study, we explore the circulation of low pathogenic avian influenza (LPAI) viruses in wild birds and poultry in the Netherlands. Surveillance data collected between 2006 and 2016 was used to evaluate subtype diversity, spatiotemporal distribution and genetic relationships between wild bird and poultry viruses. We observed close species-dependent associations among hemagglutinin and neuraminidase subtypes. Not all subtypes detected in wild birds were found in poultry, suggesting transmission to poultry is selective and likely depends on viral factors that determine host range restriction. Subtypes commonly detected in poultry were in wild birds most frequently detected in mallards and geese. Different temporal patterns in virus prevalence were observed between wild bird species. Virus detections in domestic ducks coincided with the prevalence peak in wild ducks, whereas virus detections in other poultry types were made throughout the year. Genetic analysis of the surface genes demonstrated that most poultry viruses were related to locally circulating wild bird viruses, but no direct spatiotemporal link was observed. Results indicate prolonged undetected virus circulation and frequent reassortment events with local and newly introduced viruses within the wild bird population. Increased knowledge on LPAI virus circulation can be used to improve surveillance strategies.
Assuntos
Animais Selvagens/virologia , Aves/virologia , Influenza Aviária/virologia , Animais , Países Baixos , Vigilância da População , Aves Domésticas/virologiaRESUMO
BACKGROUND: At the end of 2011, a new orthobunyavirus, tentatively named Schmallenberg virus (SBV), was discovered in Germany. This virus has since been associated with clinical signs of decreased milk production, watery diarrhoea and fever in dairy cows, and subsequently also with congenital malformations in calves, lambs and goat kids. In affected countries, initial surveillance for the infection was based on examination of malformed progeny. These suspicions were followed up by real-time reverse transcription polymerase chain reaction (RT-PCR) on brain tissue. For epidemiological purposes, a serological assay was, however, needed. RESULTS: A virus neutralisation test (VNT) was developed and optimized, and subsequently evaluated. This VNT has a specificity of >99% and the sensitivity is likely also very close to 100%. The assay is highly repeatable and reproducible. The final assay was used to test for antibodies in cows, ewes and does from herds known to be infected or suspected to be so. Targets for sampling in these herds were the mothers of malformed offspring. In herds with an RT-PCR confirmed SBV infection, more than 94% (190 out of 201) of the ewes and 99% (145 out of 146) of the cows were seropositive. In herds with suspicion of SBV infection based on birth of malformed offspring only (no or negative RT-PCR), more than 90% (231 out of 255) of the ewes and 95% (795 out of 834) of the cows were seropositive. In goats, on the other hand, only a low number of seropositives was found: overall 36.4%, being 16 out of 44 goats tested. CONCLUSIONS: Given the characteristics of this VNT, it can be used at a relative high throughput for testing of animals for export, surveillance, screening and research purposes, but can also be used as a confirmation test for commercially available enzyme-linked immunosorbent assays (ELISA's) and for (relative) quantification of antibodies.Suspicions of SBV infections that were confirmed by RT-PCR were almost always confirmed by serology in cows. Due to individual registration and identification of cows and calves, affected offspring could almost always be traced back to the mother. Ewes on the other hand were not always the mothers of affected lambs, but were in many cases herd mates with unaffected lambs. This indicated a high within-herd seroprevalence of antibodies against SBV.