scholarly journals Detection of mortality clusters associated with highly pathogenic avian influenza in poultry: a theoretical analysis

2008 ◽  
Vol 5 (29) ◽  
pp. 1409-1419 ◽  
Author(s):  
Nicholas J Savill ◽  
Suzanne G St. Rose ◽  
Mark E.J Woolhouse
Keyword(s):  
Avian Influenza ◽  
Highly Pathogenic Avian Influenza ◽  
Effective Control ◽  
False Alarms ◽  
Flock Size ◽  
Detection Thresholds ◽  
Highly Pathogenic ◽  
Pathogenic Avian Influenza ◽  
Background Mortality ◽  
Time To Detection

Rapid detection of infectious disease outbreaks is often crucial for their effective control. One example is highly pathogenic avian influenza (HPAI) such as H5N1 in commercial poultry flocks. There are no quantitative data, however, on how quickly the effects of HPAI infection in poultry flocks can be detected. Here, we study, using an individual-based mathematical model, time to detection in chicken flocks. Detection is triggered when mortality, food or water intake or egg production in layers pass recommended thresholds suggested from the experience of past HPAI outbreaks. We suggest a new threshold for caged flocks—the cage mortality detection threshold—as a more sensitive threshold than current ones. Time to detection is shown to depend nonlinearly on R 0 and is particularly sensitive for R 0 <10. It also depends logarithmically on flock size and number of birds per cage. We also examine how many false alarms occur in uninfected flocks when we vary detection thresholds owing to background mortality. The false alarm rate is shown to be sensitive to detection thresholds, dependent on flock size and background mortality and independent of the length of the production cycle. We suggest that current detection thresholds appear sufficient to rapidly detect the effects of a high R 0 HPAI strain such as H7N7 over a wide range of flock sizes. Time to detection of the effects of a low R 0 HPAI strain such as H5N1 can be significantly improved, particularly for large flocks, by lowering detection thresholds, and this can be accomplished without causing excessive false alarms in uninfected flocks. The results are discussed in terms of optimizing the design of disease surveillance programmes in general.

scholarly journals Genetic evolution and transmission dynamics of clade 2.3.2.1a highly pathogenic avian influenza A/H5N1 viruses in Bangladesh

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Jung-Hoon Kwon ◽  
Dong-Hun Lee ◽  
Miria Ferreira Criado ◽  
Lindsay Killmaster ◽  
Md Zulfekar Ali ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Avian Influenza ◽  
Influenza A ◽  
Highly Pathogenic Avian Influenza ◽  
Influenza Viruses ◽  
Effective Control ◽  
Highly Pathogenic ◽  
Pathogenic Avian Influenza ◽  
History Of ◽  
Genetic Sequences

Abstract Asian lineage A/H5N1 highly pathogenic avian influenza viruses (HPAIVs) have been responsible for continuous outbreaks in Bangladesh since 2007. Although clades 2.2.2 and 2.3.4.2 HPAIVs have disappeared since poultry vaccination was introduced in 2012, clade 2.3.2.1a viruses have continued to be detected in Bangladesh. In this study, we identified A/H9N2 (n = 15), A/H5N1 (n = 19), and A/H5N1-A/H9N2 (n = 18) mixed viruses from live bird markets, chicken farms, and wild house crows (Corvus splendens) in Bangladesh from 2016 to 2018. We analyzed the genetic sequences of the H5 HPAIVs, to better understand the evolutionary history of clade 2.3.2.1a viruses in Bangladesh. Although seven HA genetic subgroups (B1–B7) and six genotypes (G1, G1.1, G1.2, G2, G2.1, and G2.2) have been identified in Bangladesh, only subgroup B7 and genotypes G2, G2.1, and G2.2 were detected after 2016. The replacement of G1 genotype by G2 in Bangladesh was possibly due to vaccination and viral competition in duck populations. Initially, genetic diversity decreased after introduction of vaccination in 2012, but in 2015, genetic diversity increased and was associated with the emergence of genotype G2. Our phylodynamic analysis suggests that domestic Anseriformes, including ducks and geese, may have played a major role in persistence, spread, evolution, and genotype replacement of clade 2.3.2.1a HPAIVs in Bangladesh. Thus, improvements in biosecurity and monitoring of domestic Anseriformes are needed for more effective control of HPAI in Bangladesh.

scholarly journals Mortality Levels and Production Indicators for Suspicion of Highly Pathogenic Avian Influenza Virus Infection in Commercially Farmed Ducks

Pathogens ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1498
Author(s):  
Armin R. W. Elbers ◽  
José L. Gonzales
Keyword(s):  
Avian Influenza ◽  
Water Intake ◽  
Egg Production ◽  
Highly Pathogenic Avian Influenza ◽  
Severe Disease ◽  
Influenza Virus Infection ◽  
False Alarms ◽  
Daily Mortality ◽  
Highly Pathogenic ◽  
Pathogenic Avian Influenza

(1) Background: Highly pathogenic avian influenza (HPAI) is a viral infection characterized by inducing severe disease and high levels of mortality in gallinaceous poultry. Increased mortality, drop in egg production or decreased feed or water intake are used as indicators for notification of suspicions of HPAI outbreaks. However, infections in commercial duck flocks may result in mild disease with low mortality levels, thereby compromising notifications. (2) Methods: Data on daily mortality, egg production, feed intake and water intake from broiler and breeder duck flocks not infected (n = 56 and n = 11, respectively) and infected with HPAIV (n = 13, n = 4) were used for analyses. Data from negative flocks were used to assess the baseline (daily) levels of mortality and production parameters and to identify potential threshold values for triggering suspicions of HPAI infections and assess the specificity (Sp) of these thresholds. Data from infected flocks were used to assess the effect of infection on daily mortality and production and to evaluate the sensitivity (Se) of the thresholds for early detection of outbreaks. (3) Results: For broiler flocks, daily mortality > 0.3% (after the first week of production) or using a regression model for aberration detection would indicate infection with Se and Sp higher than 80%. Drops in mean daily feed or water intake larger than 7 g or 14 mL (after the first week of production), respectively, are sensitive indicators of infection but have poor Sp. For breeders, mortality thresholds are poor indicators of infection (low Se and Sp). However, a consecutive drop in egg production larger than 9% is an effective indicator of a HPAI outbreak. For both broiler and breeder duck flocks, cumulative average methods were also assessed, which had high Se but generated many false alarms (poor Sp). (4) Conclusions: The identified reporting thresholds can be used to update legislation and provide guidelines to farmers and veterinarians to notify suspicions of HPAI outbreaks in commercial duck flocks.

scholarly journals A metapopulation model for highly pathogenic avian influenza: implications for compartmentalization as a control measure

2013 ◽  
Vol 142 (9) ◽  
pp. 1813-1825 ◽  
Author(s):  
S. NICKBAKHSH ◽  
L. MATTHEWS ◽  
S. W. J. REID ◽  
R. R. KAO
Keyword(s):  
Avian Influenza ◽  
Highly Pathogenic Avian Influenza ◽  
Control Measure ◽  
Effective Control ◽  
Poultry Industry ◽  
Long Distance ◽  
Highly Pathogenic ◽  
Economic Implications ◽  
Pathogenic Avian Influenza ◽  
Network Links

SUMMARYAlthough the compartmentalization of poultry industry components has substantial economic implications, and is therefore a concept with huge significance to poultry industries worldwide, the current requirements for compartment status are generic to all OIE member countries. We examined the consequences for potential outbreaks of highly pathogenic avian influenza in the British poultry industry using a metapopulation modelling framework. This framework was used to assess the effectiveness of compartmentalization relative to zoning control, utilizing empirical data to inform the structure of potential epidemiological contacts within the British poultry industry via network links and spatial proximity. Conditions were identified where, despite the efficient isolation of poultry compartments through the removal of network-mediated links, spatially mediated airborne spread enabled spillover of infection with nearby premises making compartmentalization a more ‘risky’ option than zoning control. However, when zoning control did not effectively inhibit long-distance network links, compartmentalization became a relatively more effective control measure than zoning. With better knowledge of likely distance ranges for airborne spread, our approach could help define an appropriate minimum inter-farm distance to provide more specific guidelines for compartmentalization in Great Britain.

scholarly journals Glycosylation of the Hemagglutinin Protein of H5N1 Influenza Virus Increases Its Virulence in Mice by Exacerbating the Host Immune Response

2017 ◽  
Vol 91 (7) ◽  
Author(s):  
Dongming Zhao ◽  
Libin Liang ◽  
Shuai Wang ◽  
Tomomi Nakao ◽  
Yanbing Li ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Highly Pathogenic Avian Influenza ◽  
Influenza Viruses ◽  
Single Amino Acid ◽  
Effective Control ◽  
Highly Pathogenic ◽  
Pathogenic Avian Influenza ◽  
H5n1 Influenza ◽  
Hpai H5n1 ◽  
Ha Protein

ABSTRACT The highly pathogenic avian influenza (HPAI) H5N1 viruses continue to circulate in nature and threaten public health. Although several viral determinants and host factors that influence the virulence of HPAI H5N1 viruses in mammals have been identified, the detailed molecular mechanism remains poorly defined and requires further clarification. In our previous studies, we characterized two naturally isolated HPAI H5N1 viruses that had similar viral genomes but differed substantially in their lethality in mice. In this study, we explored the molecular determinants and potential mechanism for this difference in virulence. By using reverse genetics, we found that a single amino acid at position 158 of the hemagglutinin (HA) protein substantially affected the systemic replication and pathogenicity of these H5N1 influenza viruses in mice. We further found that the G158N mutation introduced an N-linked glycosylation at positions 158 to 160 of the HA protein and that this N-linked glycosylation enhanced viral productivity in infected mammalian cells and induced stronger host immune and inflammatory responses to viral infection. These findings further our understanding of the determinants of pathogenicity of H5N1 viruses in mammals. IMPORTANCE Highly pathogenic avian influenza (HPAI) H5N1 viruses continue to evolve in nature and threaten human health. Key mutations in the virus hemagglutinin (HA) protein or reassortment with other pandemic viruses endow HPAI H5N1 viruses with the potential for aerosol transmissibility in mammals. A thorough understanding of the pathogenic mechanisms of these viruses will help us to develop more effective control strategies; however, such mechanisms and virulent determinants for H5N1 influenza viruses have not been fully elucidated. In this study, we identified glycosylation at positions 158 to 160 of the HA protein of two naturally occurring H5N1 viruses as an important virulence determinant. This glycosylation event enhanced viral productivity, exacerbated the host response, and thereby contributed to the high pathogenicity of H5N1 virus in mice.

scholarly journals First detection of highly pathogenic avian influenza virus in Norway

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Knut Madslien ◽  
Torfinn Moldal ◽  
Britt Gjerset ◽  
Sveinn Gudmundsson ◽  
Arne Follestad ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Highly Pathogenic Avian Influenza ◽  
Wild Birds ◽  
Zoonotic Potential ◽  
Active Monitoring ◽  
Main Hypothesis ◽  
Highly Pathogenic ◽  
Pathogenic Avian Influenza ◽  
Poultry Farms

Abstract Background Several outbreaks of highly pathogenic avian influenza (HPAI) caused by influenza A virus of subtype H5N8 have been reported in wild birds and poultry in Europe during autumn 2020. Norway is one of the few countries in Europe that had not previously detected HPAI virus, despite widespread active monitoring of both domestic and wild birds since 2005. Results We report detection of HPAI virus subtype H5N8 in a wild pink-footed goose (Anser brachyrhynchus), and several other geese, ducks and a gull, from south-western Norway in November and December 2020. Despite previous reports of low pathogenic avian influenza (LPAI), this constitutes the first detections of HPAI in Norway. Conclusions The mode of introduction is unclear, but a northward migration of infected geese or gulls from Denmark or the Netherlands during the autumn of 2020 is currently our main hypothesis for the introduction of HPAI to Norway. The presence of HPAI in wild birds constitutes a new, and ongoing, threat to the Norwegian poultry industry, and compliance with the improved biosecurity measures on poultry farms should therefore be ensured. [MK1]Finally, although HPAI of subtype H5N8 has been reported to have very low zoonotic potential, this is a reminder that HPAI with greater zoonotic potential in wild birds may pose a threat in the future. [MK1]Updated with a sentence emphasizing the risk HPAI pose to poultry farms, both in the Abstract and in the Conclusion-section in main text, as suggested by Reviewer 1 (#7).

scholarly journals Differential Diagnosis for Highly Pathogenic Avian Influenza Virus Using Nanoparticles Expressing Chemiluminescence

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1274
Author(s):  
Jihee Kim ◽  
Jae-Yeon Park ◽  
Jihoon Ryu ◽  
Hyun-Jin Shin ◽  
Jung-Eun Park
Keyword(s):  
Avian Influenza ◽  
Fluorescent Protein ◽  
Highly Pathogenic Avian Influenza ◽  
Systemic Disease ◽  
Renilla Luciferase ◽  
Highly Pathogenic ◽  
Pathogenic Avian Influenza ◽  
Pathogenic Avian Influenza Virus ◽  
Green Fluorescent ◽  
Transmembrane Serine Protease

Highly pathogenic avian influenza (HPAI) virus is a causative agent of systemic disease in poultry, characterized by high mortality. Rapid diagnosis is crucial for the control of HPAI. In this study, we aimed to develop a differential diagnostic method that can distinguish HPAI from low pathogenic avian influenza (LPAI) viruses using dual split proteins (DSPs). DSPs are chimeras of an enzymatic split, Renilla luciferase (RL), and a non-enzymatic split green fluorescent protein (GFP). Nanoparticles expressing DSPs, sialic acid, and/or transmembrane serine protease 2 (TMPRSS2) were generated, and RL activity was determined in the presence of HPAI or LPAI pseudotyped viruses. The RL activity of nanoparticles containing both DSPs was approximately 2 × 106 RLU, indicating that DSPs can be successfully incorporated into nanoparticles. The RL activity of nanoparticles containing half of the DSPs was around 5 × 101 RLU. When nanoparticles containing half of the DSPs were incubated with HPAI pseudotyped viruses at low pH, RL activity was increased up to 1 × 103 RLU. However, LPAI pseudotyped viruses produced RL activity only in the presence of proteases (trypsin or TMPRSS2), and the average RL activity was around 7 × 102 RLU. We confirmed that nanoparticle fusion assay also diagnoses authentic viruses with specificity of 100% and sensitivity of 91.67%. The data indicated that the developed method distinguished HPAI and LPAI, and suggested that the diagnosis using DSPs could be used for the development of differential diagnostic kits for HPAI after further optimization.

scholarly journals Highly Pathogenic Avian Influenza Viruses at the Wild–Domestic Bird Interface in Europe: Future Directions for Research and Surveillance

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 212
Author(s):  
Josanne H. Verhagen ◽  
Ron A. M. Fouchier ◽  
Nicola Lewis
Keyword(s):  
Avian Influenza ◽  
Highly Pathogenic Avian Influenza ◽  
Wild Birds ◽  
Influenza Viruses ◽  
Highly Pathogenic ◽  
Future Directions ◽  
Pathogenic Avian Influenza ◽  
Domestic Bird ◽  
Hpai H5n1 ◽  
Host Identification

Highly pathogenic avian influenza (HPAI) outbreaks in wild birds and poultry are no longer a rare phenomenon in Europe. In the past 15 years, HPAI outbreaks—in particular those caused by H5 viruses derived from the A/Goose/Guangdong/1/1996 lineage that emerged in southeast Asia in 1996—have been occuring with increasing frequency in Europe. Between 2005 and 2020, at least ten HPAI H5 incursions were identified in Europe resulting in mass mortalities among poultry and wild birds. Until 2009, the HPAI H5 virus outbreaks in Europe were caused by HPAI H5N1 clade 2.2 viruses, while from 2014 onwards HPAI H5 clade 2.3.4.4 viruses dominated outbreaks, with abundant genetic reassortments yielding subtypes H5N1, H5N2, H5N3, H5N4, H5N5, H5N6 and H5N8. The majority of HPAI H5 virus detections in wild and domestic birds within Europe coincide with southwest/westward fall migration and large local waterbird aggregations during wintering. In this review we provide an overview of HPAI H5 virus epidemiology, ecology and evolution at the interface between poultry and wild birds based on 15 years of avian influenza virus surveillance in Europe, and assess future directions for HPAI virus research and surveillance, including the integration of whole genome sequencing, host identification and avian ecology into risk-based surveillance and analyses.

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