Loss of Fitness of Mexican H7N3 Highly Pathogenic Avian Influenza Virus in Mallards after Circulating in Chickens

Youk, Sungsu; Lee, Donghun; Leyson, Christina M.; Smith, Diane; Criado, Miriã Ferreira; DeJesus, Eric; Swayne, David E.; Pantin‐Jackwood, Mary J.

doi:10.1128/jvi.00543-19

Cited by 14 publications

(16 citation statements)

References 80 publications

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“…H7N3 viruses isolated from Mexico have been further analyzed for protection in chickens and for their fitness in chickens and mallards. Variations in protection and fitness have been found between viruses isolated from different years as shown in recent reports [7,8].…”

Section: Introductionmentioning

confidence: 77%

Maternally-Derived Antibodies Protect against Challenge with Highly Pathogenic Avian Influenza Virus of the H7N3 Subtype

et al. 2019

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Vaccination of hens against influenza leads to the transfer of protective maternally-derived antibodies (MDA) to hatchlings. However, little is known about the transfer of H7N3 vaccine-induced MDA. Here, we evaluated transfer, duration, and protective effect of MDA in chickens against H7N3 HPAIV. To generate chickens with MDA (MDA (+)), 15-week-old White Leghorn hens were vaccinated and boosted twice with an inactivated H7N3 low pathogenic avian influenza virus vaccine, adjuvanted with Montanide ISA 71 VG. One week after the final boost, eggs were hatched. Eggs from non-vaccinated hens were hatched for chickens without MDA (MDA (−)). Both MDA (+) and MDA (−) hatchlings were monitored weekly for antibody levels. Anti-HA MDA were detected by hemagglutination inhibition assay mostly until day 7 post-hatch. However, anti-nucleoprotein MDA were still detected three weeks post-hatch. Three weeks post-hatch, chickens were challenged with 106 EID50/bird of Mexican-origin H7N3 HPAIV. Interestingly, while 0% of the MDA (−) chickens survived the challenge, 95% of the MDA (+) chickens survived. Furthermore, virus shedding was significantly reduced by day 5 post-challenge in the MDA (+) group. In conclusion, MDA confers partial protection against mortality upon challenge with H7N3 HPAIV, as far as three weeks post-hatch, even in the absence of detectable anti-HA antibodies, and reduce virus shedding after challenge.

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Section: Introductionmentioning

confidence: 77%

Maternally-Derived Antibodies Protect against Challenge with Highly Pathogenic Avian Influenza Virus of the H7N3 Subtype

et al. 2019

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“…The layer chickens used in this study were 35-week-old and had brown feathers, which are recognized as exhibiting reduced virulence against HPAI 24 . Additionally, the pathogenesis of avian influenza might be showed in the difference of susceptibility depending on age in various reports [25][26][27][28][29] although it was recently reported that age is not a determinant factor in susceptibility to H5N2 HPAIv 30 . Our results are not consistent with a previous study showing that commercial chickens experienced less immunization than laboratory chickens due to maternal antibodies, immunosuppressive viruses, and the use of a lower vaccine dose 31 .…”

Section: Discussionmentioning

confidence: 99%

Protection of layers and breeders against homologous or heterologous HPAIv by vaccines from Korean national antigen bank

Kang

Cho

Kim

et al. 2020

Sci Rep

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Korean government has selected and stocked five type antigens of two clades as Korean national antigen bank having high possibility of introduction to Korea. We aimed to evaluate the efficacy of the clade 2.3.2.1c and 2.3.4.4c H5Nx vaccines from the Korean avian influenza (AI) national antigen bank for emergency preparedness for their potency and protective efficacy against lethal homologous and heterologous viruses in layer and breeder chickens practically. The PD 50 (dose of vaccine that protects 50% of chickens from viral challenge) of all vaccinated groups was >50, which was satisfied with minimum antigen requirement of oie, and the pD 50 levels of the two vaccines differed depending on strain and chicken breed. In homologous challenge, all vaccinated groups exhibited 100% survival with no clinical symptoms and high levels of pre-challenge protective immunity (7.2-8.5 log 2), although they did not completely prevent virus shedding. On the other hand, against heterologous virus challenge, vaccinated animals exhibited 62.5-80% survival with lower antibody titers (2.3-3.4 log 2) and a longer period of virus shedding (14 days post infection [dpi]). Our results suggest that the clade 2.3.2.1c and 2.3.4.4c H5Nx vaccines are good candidates for emergency vaccination of commercial chickens and support the idea that close genetic matching between vaccine and challenge virus provides the best protection. An H5N1 highly pathogenic avian influenza (HPAI) A virus (A/Goose/Guangdong/1/96; Gs/GD/96) was first detected in China in 1996 and subsequently spread into Hong Kong in 1997, causing massive economic losses to the poultry industry 1,2. Since 1997, multiple clades have evolved and spread across Asia, Africa, and Europe 3. In Korea, H5Nx HPAI have been detected in both poultry farms and wild birds since 2003, including clades 2.5, 2.2, 2.3.2, 2.3.2.1, 2.3.4.4a, 2.3.4.4c, and 2.3.4.4b 4-8. In particular, HPAI outbreaks of two subtypes (H5N6 and H5N8) were reported in 343 and 76 poultry farms in 2016 and 2017, respectively. This period was associated with an unprecedented level of damage to the poultry industry in Korea: 38 million animals were culled, resulting in huge financial losses (approximately $312 million). AI vaccination in conjunction with surveillance and depopulation was required by some poultry producers and animal-welfare organizations. Accordingly, the Korean government has selected and stocked five types of antigens corresponding to two clades with a high risk of introduction into Korea, 2.3.2.1c and 2.3.4.4a, b, c and d (H5Nx), as a national AI antigen bank 9. Laboratory experiments related to inactivated vaccine development, using oil adjuvant in SPF (specific pathogen-free) chickens, have been conducted to assess correlates of vaccine efficacy such as prevention of mortality, reduction of infection rate, and reduction of viral shedding 10-12. However, some studies reported that commercial poultry in the field do not achieve the same levels of vaccine efficacy as SPF chickens in the laboratory, due to m...

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“…The numbers of sequences used for phylogenetic analysis are as follow: PB2 (n = 393), PB1 (n = 350), PA (n = 376), HA (n = 372), NP (= 358), NA (n = 398), M (n = 343), and NS (n = 305). In addition to the viruses sequenced in this study, full genome sequences of 18 viruses available in the Influenza Research Database, including viruses previously sequenced in our laboratory were retrieved (access date: July 2018) for full genome analysis of the Mexican H7N3 viruses from 2012 to 2017 [15]. For the estimations of substitution rate using the Bayesian analyses, the wild bird AI sequences clustering with the initial Mexican H7N3 sequences were extracted from the Maximum-likelihood phylogenetic trees, with bootstrap value (n > 70).…”

Section: Methodsmentioning

confidence: 99%

“…In previous studies, we demonstrated phenotypic and antigenic changes in recent Mexican lineage H7N3 viruses. A H7N3 HPAI virus isolated in 2016 was less adapted to mallards than the index virus from 2012, and increase in N-glycosylation on the HA was associated with escape of a field virus from a older vaccine [15, 16]. However, detailed information on the evolutionary history of the Mexican lineage H7N3 HPAI virus is lacking.…”

Section: Introductionmentioning

confidence: 99%

Rapid evolution of Mexican H7N3 highly pathogenic avian influenza viruses in poultry

et al. 2019

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Highly pathogenic avian influenza (HPAI) virus subtype H7N3 has been circulating in poultry in Mexico since 2012 and vaccination has been used to control the disease. In this study, eight Mexican H7N3 HPAI viruses from 2015–2017 were isolated and fully sequenced. No evidence of reassortment was detected with other avian influenza (AI) viruses, but phylogenetic analyses show divergence of all eight gene segments into three genetic clusters by 2015, with 94.94 to 98.78 percent nucleotide homology of the HA genes when compared to the index virus from 2012. The HA protein of viruses from each cluster showed a different number of basic amino acids (n = 5–7) in the cleavage site, and six different patterns at the predicted N-glycosylation sites. Comparison of the sequences of the Mexican lineage H7N3 HPAI viruses and American ancestral wild bird AI viruses to characterize the virus evolutionary dynamics showed that the nucleotide substitution rates in PB2, PB1, PA, HA, NP, and NS genes greatly increased once the virus was introduced into poultry. The global nonsynonymous and synonymous ratios imply strong purifying selection driving the evolution of the virus. Forty-nine positively selected sites out of 171 nonsynonymous mutations were identified in the Mexican H7N3 HPAI viruses, including 7 amino acid changes observed in higher proportion in North American poultry origin AI viruses isolates than in wild bird-origin viruses. Continuous monitoring and molecular characterization of the H7N3 HPAI virus is important for better understanding of the virus evolutionary dynamics and further improving control measures including vaccination.

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Loss of Fitness of Mexican H7N3 Highly Pathogenic Avian Influenza Virus in Mallards after Circulating in Chickens

Cited by 14 publications

References 80 publications

Maternally-Derived Antibodies Protect against Challenge with Highly Pathogenic Avian Influenza Virus of the H7N3 Subtype

Maternally-Derived Antibodies Protect against Challenge with Highly Pathogenic Avian Influenza Virus of the H7N3 Subtype

Protection of layers and breeders against homologous or heterologous HPAIv by vaccines from Korean national antigen bank

Rapid evolution of Mexican H7N3 highly pathogenic avian influenza viruses in poultry

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