Minimizing the vulnerability of poultry production chains for avian influenza

Highly pathogenic avian influenza viruses (HPAIV) emerge from low pathogenic avian influenza viruses (LPAIV) through the introduction of basic amino acids at the hemagglutinin (HA) cleavage site. Following viral evolution, the newly formed HPAIV likely represents a minority variant within the index host, predominantly infected with the LPAIV precursor. Using reverse-genetics engineered H5N8 viruses differing solely at the HA cleavage, we tested the hypothesis that the interaction between the minority HPAIV and the majority LPAIV could modulate the risk of HPAIV emergence and that the nature of the interaction could depend on the host species. In chickens, we observed that the H5N8 LP increased H5N8 HP replication and pathogenesis. By contrast, the H5N8 LP antagonized H5N8 HP replication and pathogenesis in ducks. Ducks mounted a more potent antiviral innate immune response than chickens against the H5N8 LP , which correlated with H5N8 HP inhibition. These data provide experimental evidence that HPAIV may be more likely to emerge in chickens than in ducks and underscore the importance of within-host viral variants interactions in viral evolution. IMPORTANCE Highly pathogenic avian influenza viruses represent a threat to poultry production systems and to human health because of their impact on food security and because of their zoonotic potential. It is therefore crucial to better understand how these viruses emerge. Using a within-host competition model between highly and low pathogenic avian influenza viruses, we provide evidence that highly pathogenic avian influenza viruses could be more likely to emerge in chickens than in ducks. These results have important implications for highly pathogenic avian influenza virus emergence prevention and they underscore the importance of within-host viral variants interactions in virus evolution.

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1438Dynamics of inter-farm transmission of highly pathogenic avian influenza integrating vehicle movements and phylogenetic information

International Journal of Epidemiology ◽

10.1093/ije/dyab168.736 ◽

2021 ◽

Vol 50 (Supplement_1) ◽

Author(s):

Dae-sung Yoo ◽

Chun Byung Chul

Keyword(s):

Network Analysis ◽

Avian Influenza ◽

Highly Pathogenic Avian Influenza ◽

Control Strategies ◽

Poultry Production ◽

Movement Restriction ◽

Phylogenetic Information ◽

Highly Pathogenic ◽

Pathogenic Avian Influenza ◽

And Control

Abstract Background Highly pathogenic avian influenza (HPAI), a zoonotic infectious disease, has been considered a severe threat to public health. The fundamental prevention and control strategy against HPAI includes minimizing the outbreaks of poultry holdings where the virus primarily spreads through animal trade and poultry production associated vehicle movement (PPVM). However, very few attempts have been made to elucidate the association between PPVM and HPAI transmission compared to studies on poultry trade. Therefore, our study aimed to elucidate the role of PPVM on HPAI transmission. Methods We performed network analysis using PPVM data based on a global positioning system (GPS), with phylogenetic information of the HPAI virus for reliable estimation. Moreover, the contribution of PPVM to HPAI infection was estimated by Bayesian inference. Results The network analysis revealed that the connection via PPVM between the same genetic group of infected premises (IPs) was more prevalent than that of different genotype IPs. Moreover, the similarity of farm poultry species and the overlapped integrators between inter-linked IPs was associated with potential transmission route formation. Additionally, the contribution of PPVM among phylogenetically clustered IPs was estimated to have 28.25% of HPAI infections in IPs on average. Conclusions HPAI control strategies including targeted movement restriction and standstill should be established against the HPAI transmission via PPVM. Key messages This is a solid and novel study depicting the need for combining epidemiological analysis with data regarding molecular epidemiology of pathogens.

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Sero-Detection of Avian Influenza A/H7 in Nigerian Live-Bird Markets in Plateau State

Nigerian Veterinary Journal ◽

10.4314/nvj.v41i2.7 ◽

2021 ◽

Vol 41 (2) ◽

pp. 161-174

Author(s):

C.N. Chinyere ◽

E.C. Okwor ◽

C.A. Meseko ◽

W.S. Ezema ◽

N.D. Choji ◽

...

Keyword(s):

Influenza Virus ◽

Avian Influenza ◽

Influenza A ◽

Haemagglutination Inhibition ◽

Poultry Production ◽

Live Bird Market ◽

Live Bird Markets ◽

Plateau State ◽

Keywords Influenza ◽

Live Bird

Avian influenza has been reported in domestic birds in Nigeria since 2006 and subtype H5 of the Gs/Gg lineage has continued to be detected up till date. It has been suggested that waterfowls and local birds sold in live-bird markets may be natural reservoir and source of reinfection of different subtype of avian influenza in poultry farms. This study aims at serodetection of avian influenza virus in waterfowls and local birds at live-bird markets in Plateau State, Nigeria. A total of three hundred and nine (309) blood samples were collected over a period of three months and two hundred and ninety-two (292) sera were analysed by c-ELISA for influenza A nucleoprotein using standard protocols. Haemagglutination Inhibition (HI) specific for subtypes H5, H9, and H7 was also carried out using standard protocols on ELISA positive samples. The results showed seroprevalence of 5.14% (n=15) for influenza A. Serotype H7 was thereafter detected by HI in 5 of the 15 influenza A positive samples. The H7 positive sera also reacted with H7N3, H7N4, H7N1 and H7N7 virus strains with HI titre ranging between 1:32 to 1:512. This investigation for the first time showed serological evidence of influenza A subtype H7 in local birds and waterfowls sold at the live bird market in Nigeria. Further virological surveillance to isolate the virus is important in order to better understand influenza virus epidemiology in Nigeria and the potential risk that other subtypesof influenza poses to poultry production and public health. Keywords: Influenza A, subtype H7, serological detection, live bird market, Nigeria.

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Controlling Avian Influenza Virus in Bangladesh: Challenges and Recommendations

Viruses ◽

10.3390/v12070751 ◽

2020 ◽

Vol 12 (7) ◽

pp. 751

Author(s):

Rokshana Parvin ◽

Mohammed Nooruzzaman ◽

Congriev Kumar Kabiraj ◽

Jahan Ara Begum ◽

Emdadul Haque Chowdhury ◽

...

Keyword(s):

Influenza Virus ◽

Avian Influenza ◽

Avian Influenza Virus ◽

Control Strategies ◽

Poultry Production ◽

New Host ◽

Multiple Virus ◽

Virus Spreading ◽

Virus Strains ◽

New Host Species

Avian influenza virus (AIV) remains a huge challenge for poultry production with negative repercussions for micro- and macro-economy and public health in Bangladesh. High (HP) H5N1 and low pathogenicity (LP) H9N2 AIV are currently endemic in poultry, and both have been reported to infect humans sporadically. Multiple virus introductions of different clades of HPAIV H5N1, reassorted genotypes, and on-going diversification of LPAIV H9N2 create a highly volatile virological environment which potentially implicates increased virulence, adaptation to new host species, and subsequent zoonotic transmission. Allotropy of poultry rearing systems and supply chains further increase the risk of virus spreading, which leads to human exposure and fosters the emergence of new potentially pre-pandemic virus strains. Here, we review the epidemiology, focusing on (i) risk factors for virus spreading, (ii) viral genetic evolution, and (iii) options for AIV control in Bangladesh. It is concluded that improved control strategies would profit from the integration of various intervention tools, including effective vaccination, enhanced biosecurity practice, and improved awareness of producers and traders, although widespread household poultry rearing significantly interferes with any such strategies. Nevertheless, continuous surveillance associated with rapid diagnosis and thorough virus characterization is the basis of such strategies.

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Mortality and Pathology Associated with Highly Pathogenic Avian Influenza H5N1 Outbreaks in Commercial Poultry Production Systems in Nigeria

International Scholarly Research Notices ◽

10.1155/2014/415418 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 5

Author(s):

Olatunde Babatunde Akanbi ◽

Victor Olusegun Taiwo

Keyword(s):

Avian Influenza ◽

Production Systems ◽

Highly Pathogenic Avian Influenza ◽

Poultry Production ◽

Highly Pathogenic ◽

Pathogenic Avian Influenza ◽

Hpai H5n1 ◽

Commercial Poultry ◽

The One ◽

Influenza H5n1

Commercial layer-type, pullet, cockerel, and broiler chicken flocks infected with highly pathogenic avian influenza (HPAI) H5N1 in Nigeria between 2006 and 2008 were investigated for morbidity, mortality, and pathology. Of the one hundred and fifty-three (153) farms confirmed with HPAI infection, one hundred and twenty-seven (127) were layer-type farms, nine (9) were pullet and broiler farms each, and eight (8) were cockerel rearing farms. This study revealed the morbidity and mortality of a total of 939,620 commercial layer chickens, 16,421 pullets, 3,109 cockerels, and 6,433 broilers. Mortality rates were 11.11% in commercial layers, 26.84% in pullets, 45.51% in cockerels, and 73.92% in broilers in a total of eighteen (18) states and the Federal Capital Territory, Abuja. A total of 316 carcasses were examined of which 248 were commercial layer, 25 were pullet, 14 were cockerel, and 29 were broiler. Main clinical and pathologic findings were observed in the nervous, circulatory, respiratory, integumentary, musculoskeletal, hemopoietic, gastrointestinal, and reproductive systems and, occasionally, lesions were generally nonspecific and multisystemic. Lesions occurred more frequently, severely, and in most of the carcasses examined, irrespective of chicken type.

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Characteristics of Diagnostic Tests Used in the 2002 Low-Pathogenicity Avian Influenza H7N2 Outbreak in Virginia

Journal of Veterinary Diagnostic Investigation ◽

10.1177/104063870701900401 ◽

2007 ◽

Vol 19 (4) ◽

pp. 341-348 ◽

Cited By ~ 18

Author(s):

François Elvinger ◽

Bruce L. Akey ◽

Dennis A. Senne ◽

F. William Pierson ◽

Barbara A. Porter-Spalding ◽

...

Keyword(s):

Avian Influenza ◽

Diagnostic Tests ◽

Low Cost ◽

Clinical Signs ◽

Poultry Production ◽

Production Region ◽

Bayesian Techniques ◽

Shenandoah Valley ◽

Virus Rna ◽

Rapid Control

An outbreak of low-pathogenicity avian influenza (LPAI) H7N2 occurred in 2002 in the Shenandoah Valley, a high-density poultry production region in Virginia. Infected flocks were identified through a combination of observation of clinical signs and laboratory diagnostic tests designed to detect avian influenza (AI) antibodies, virus, or H7-specific RNA. In this report, fitness for purpose of 3 virus/RNA detection assays used during the outbreak was examined: 1) antigen capture enzyme immunoassay (AC-EIA), 2) real-time reverse transcription polymerase chain reaction (RRT-PCR), and 3) virus isolation (VI). Results from testing 762 turkey and 2,216 chicken tracheal swab pooled specimens were analyzed to determine diagnostic sensitivities and specificities of these tests under field conditions using Bayesian techniques for validation of diagnostic tests in the absence of a “gold standard.” Diagnostic sensitivities (with 95% probability intervals) in turkeys of AC-EIA and RRT-PCR, in reference to VI, were 65.9 (50.6; 81.3)% and 85.1 (71.9; 95.7)% and of VI 92.9 (78.0; 98.8)% in reference to AC-EIA or 88.7 (76.0; 97.2)% in reference to RRT-PCR; in chickens, diagnostic sensitivities were 75.1 (45.6; 94.2)%, 86.3 (65.9; 97.1)%, and 86.2 (65.8; 97.1)% or 86.3 (66.4; 97.2)%, respectively. Specificities were 99.1 (97.9; 99.8)%, 98.9 (98.0; 99.5)%, and 98.6 (97.4; 99.4)% or 98.8 (97.8; 99.5)% in turkeys and between 99.25% and 99.27% with probability intervals of approximately ±0.4% for all tests in chickens. Simultaneous use of AC-EIA and RRT-PCR contributed significantly to the rapid control of the outbreak, but the AI RRT-PCR assay with >85% sensitivity and ∼99% specificity, combined with relatively low cost and fast turnaround, could be used as the sole diagnostic test in outbreaks of LPAI.

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Effect of Avian Influenza H9N2 Subtype Virus Infection on Backyard Poultry Production

Science Letters ◽

10.47262/sl/9.1.132021005 ◽

2021 ◽

Vol 9 (1) ◽

pp. 19-23

Keyword(s):

Avian Influenza ◽

Influenza Viruses ◽

Economic Losses ◽

Poultry Production ◽

Poultry Industry ◽

Backyard Poultry ◽

H9n2 Subtype ◽

Pathogenic Avian Influenza ◽

The World ◽

Avian Influenza H9n2

Avian influenza is a viral pandemic disease of humans and birds, including commercial and house poultry. Avian influenza is a major concern around the world, which causes serious economic losses in the poultry industry, mainly in home backyard poultry. The backyard poultry is the potential source of income for rural people and indirectly contributes to decreasing the poverty of household women. Besides, in many developing countries, villagers full fill a part of their food demand by the backyard poultry; however, this sector is directly affected by biosecurity risks, including high and low pathogenic avian influenza infections like avian influenza H9N2 subtype. Avian influenza H9N2 subtype has low pathogenic zoonotic importance but still causes serious threats to the poultry industry. The backyard poultry industry is directly affected by this infection due to direct contact with wild migratory birds locating in different regions of the world. Antigenic drift and shift are one of the major conflicts of this infection resulting from a few days to a few months up to many years and also the main reason for the uncontrollable mutation in this infection. All over the world, there is no serious action taken to prevent the H9N2 subtype infection in backyard poultry. This situation has become severe because of the widespread of highly pathogenic avian influenza viruses in the past few years.

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Dynamics of inter-farm transmission of highly pathogenic avian influenza H5N6 integrating vehicle movements and phylogenetic information

Scientific Reports ◽

10.1038/s41598-021-03284-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Dae-Sung Yoo ◽

Byung chul Chun ◽

Younjung Kim ◽

Kwang-Nyeong Lee ◽

Oun-Kyoung Moon

Keyword(s):

Network Analysis ◽

Avian Influenza ◽

Highly Pathogenic Avian Influenza ◽

Control Strategies ◽

Scientific Basis ◽

Contact Network ◽

Poultry Production ◽

Phylogenetic Information ◽

Highly Pathogenic ◽

Pathogenic Avian Influenza

AbstractHighly pathogenic avian influenza (HPAI) in poultry holdings commonly spreads through animal trade, and poultry production and health-associated vehicle (PPHaV) movement. To effectively control the spread of disease, it is essential that the contact structure via those movements among farms is thoroughly explored. However, few attempts have been made to scrutinize PPHaV movement compared to poultry trade. Therefore, our study aimed to elucidate the role of PPHaV movement on HPAI transmission. We performed network analysis using PPHaV movement data based on a global positioning system, with phylogenetic information of the isolates during the 2016–2017 HPAI H5N6 epidemic in the Republic of Korea. Moreover, the contribution of PPHaV movement to the spread of HPAI was estimated by Bayesian modeling. The network analysis revealed that there was the relationship between phylogenetic clusters and the contact network via PPHaV movement. Furthermore, the similarity of farm poultry species and the shared integrators between inter-linked infected premises (IPs) were associated with ties within the same phylogenetic clusters. Additionally, PPHaV movement among phylogenetically clustered IPs was estimated to contribute to approximately 30% of HPAI H5N6 infections in IPs on average. This study provides insight into how HPAI spread via PPHaV movement and scientific basis for control strategies.

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Contribution of Segment 3 to the Acquisition of Virulence in Contemporary H9N2 Avian Influenza Viruses

Journal of Virology ◽

10.1128/jvi.01173-20 ◽

2020 ◽

Vol 94 (20) ◽

Author(s):

Anabel L. Clements ◽

Joshua E. Sealy ◽

Thomas P. Peacock ◽

Jean-Remy Sadeyen ◽

Saira Hussain ◽

...

Keyword(s):

Middle East ◽

Avian Influenza ◽

Mortality Rates ◽

Influenza Viruses ◽

H9n2 Virus ◽

Morbidity And Mortality ◽

Single Amino Acid ◽

Economic Damage ◽

Poultry Production ◽

Avian Influenza Viruses

ABSTRACT H9N2 avian influenza viruses (AIVs) circulate in poultry throughout much of Asia, the Middle East, and Africa. These viruses cause huge economic damage to poultry production systems and pose a zoonotic threat both in their own right and in the generation of novel zoonotic viruses, for example, H7N9. In recent years, it has been observed that H9N2 viruses have further adapted to gallinaceous poultry, becoming more highly transmissible and causing higher morbidity and mortality. Here, we investigate the molecular basis for this increased virulence, comparing a virus from the 1990s and a contemporary field strain. The modern virus replicated to higher titers in various systems, and this difference mapped to a single amino acid polymorphism at position 26 of the endonuclease domain shared by the PA and PA-X proteins. This change was responsible for increased replication and higher morbidity and mortality rates along with extended tissue tropism seen in chickens. Although the PA K26E change correlated with increased host cell shutoff activity of the PA-X protein in vitro, it could not be overridden by frameshift site mutations that block PA-X expression and therefore increased PA-X activity could not explain the differences in replication phenotype. Instead, this indicates that these differences are due to subtle effects on PA function. This work gives insight into the ongoing evolution and poultry adaptation of H9N2 and other avian influenza viruses and helps us understand the striking morbidity and mortality rates in the field, as well as the rapidly expanding geographical range seen in these viruses. IMPORTANCE Avian influenza viruses, such as H9N2, cause huge economic damage to poultry production worldwide and are additionally considered potential pandemic threats. Understanding how these viruses evolve in their natural hosts is key to effective control strategies. In the Middle East and South Asia, an older H9N2 virus strain has been replaced by a new reassortant strain with greater fitness. Here, we take representative viruses and investigate the genetic basis for this “fitness.” A single mutation in the virus was responsible for greater fitness, enabling high growth of the contemporary H9N2 virus in cells, as well as in chickens. The genetic mutation that modulates this change is within the viral PA protein, a part of the virus polymerase gene that contributes to viral replication as well as to virus accessory functions—however, we find that the fitness effect is specifically due to changes in the protein polymerase activity.

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