Pathogenicity and transmission of H5N1 avian influenza viruses in different birds.
Yuan Runyu,Cui Jin,Zhang Shuo,Cao Lan,Liu Xiaoke,Kang Yinfeng,Song Yafen,Gong Lang,Jiao Peirong,Liao Ming
Veterinary microbiology
In this study, we selected three H5N1 highly pathogenic avian influenza viruses (HPAIVs), A/Goose/Guangdong/1/1996 (clades 0), A/Duck/Guangdong/E35/2012 (clade 2.3.2.1) and A/Chicken/Henan/B30/2012 (clade 7.2) isolated from different birds in China, to investigate the pathogenicity and transmission of the viruses in terrestrial birds and waterfowl. To observe the replication and shedding of the H5N1 HPAIVs in birds, the chickens were inoculated intranasally with 10(6) EID50 of GSGD/1/96, 10(3) EID50 of DkE35 and CkB30, and the ducks and geese were inoculated intranasally with 10(6) EID50 of each virus. Meanwhile, the naive contact groups were set up to detect the transmission of the viruses in tested birds. Our results showed that DkE35 was highly pathogenic to chickens and geese, but not fatal to ducks. It could be detected from all the tested organs, oropharyngeal and cloacal swabs, and could transmit to the naive contact birds. GSGD/1/96 could infect chickens, ducks and geese, but only caused death in chickens. It could transmit to the chickens and ducks, but was not transmittable to geese. CkB30 was highly pathogenic to chickens, low pathogenic to ducks and not pathogenic to geese. It could be transmitted to the naive contact chickens, but not to the ducks or geese. Our findings suggested that H5N1 HPAIVs from different birds show different host ranges and tissue tropisms. Therefore, we should enhance serological and virological surveillance of H5N1 HPAIVs, and pay more attention to the pathogenic and antigenic evolution of these viruses.
10.1016/j.vetmic.2013.10.013
Transmission dynamics between infected waterfowl and terrestrial poultry: Differences between the transmission and tropism of H5N8 highly pathogenic avian influenza virus (clade 2.3.4.4a) among ducks, chickens and turkeys.
Puranik Anita,Slomka Marek J,Warren Caroline J,Thomas Saumya S,Mahmood Sahar,Byrne Alexander M P,Ramsay Andrew M,Skinner Paul,Watson Samantha,Everett Helen E,Núñez Alejandro,Brown Ian H,Brookes Sharon M
Virology
H5N8 highly-pathogenic avian influenza viruses (HPAIVs, clade 2.3.4.4) have spread globally via migratory waterfowl. Pekin ducks infected with a UK virus (H5N8-2014) served as the donors of infection in three separate cohousing experiments to attempt onward transmission chains to sequentially introduced groups of contact ducks, chickens and turkeys. Efficient transmission occurred among ducks and turkeys up to the third contact stage, with all (100%) birds becoming infected. Introduction of an additional fourth contact group of ducks to the turkey transmission chain demonstrated retention of H5N8-2014's waterfowl-competent adaptation. However, onward transmission ceased in chickens at the second contact stage where only 13% became infected. Analysis of viral progeny at this contact stage revealed no emergent polymorphisms in the intra-species (duck) transmission chain, but both terrestrial species included changes in the polymerase and accessory genes. Typical HPAIV pathogenesis and mortality occurred in infected chickens and turkeys, contrasting with 5% mortality among ducks.
10.1016/j.virol.2019.10.014
Highly pathogenic avian influenza virus H5N6 (clade 2.3.4.4b) has a preferable host tropism for waterfowl reflected in its inefficient transmission to terrestrial poultry.
Seekings A H,Warren C J,Thomas S S,Mahmood S,James J,Byrne A M P,Watson S,Bianco C,Nunez A,Brown I H,Brookes S M,Slomka M J
Virology
Highly-pathogenic avian influenza virus (HPAIV) H5N6 (clade 2.3.4.4b) incurred into Europe in late 2017 and was predominantly detected in wild birds, with very few terrestrial poultry cases. Pekin ducks directly-infected with a UK virus (H5N6-2017) were donors of infection to investigate contact transmission to three recipient species: Ducks, chickens and turkeys. H5N6-2017 transmission to ducks was 100% efficient, but transmission to in-contact galliforme species was infrequent and unpredictable, thereby reflecting the European 2017-2018 H5N6 epidemiology. Although only two of 28 (7%) infected ducks died, the six turkeys and one chicken which became infected all died and displayed systemic H5N6-2017 dissemination, while pathogenesis in ducks was generally milder. Analysis of H5N6-2017 progeny in the contacts revealed no emergent polymorphisms in an infected duck, but the galliforme species included changes in the polymerase (PB2 A199T, PA D347A), matrix (M1 T218A) and neuraminidase genes (T88I). H5N6-2017 environmental contamination was associated with duck shedding.
10.1016/j.virol.2021.03.010
Characterizations of H4 avian influenza viruses isolated from ducks in live poultry markets and farm in Shanghai.
Shi Ying,Cui Hongrui,Wang Junheng,Chi Qiuyan,Li Xuesong,Teng Qiaoyang,Chen Hongjun,Yang Jianmei,Liu Qinfang,Li Zejun
Scientific reports
H4 avian influenza virus is one of the most prevalent influenza virus subtypes in birds. The evolution and pathogenicity of H4 AIV in domestic birds of China remain largely unclear. In the present study, a total of eight H4 AIV strains isolated in duck farm and live poultry markets (LPM) were characterized. Phylogenetic analysis indicated that these strains are divided into two groups in the Eurasian lineage. Eight genes of MH-2/H4N6 isolated from a duck farm were closely related to three H4N6 viruses from LPM, suggesting a potential AIV link between farms and LPMs. Additionally, the HA, NA, PB2, NP, and NS genes of two other H4N6 viruses isolated in LPM clustered with that of MH-2/H4N6. However, the remaining genes were more closely related to other sublineages, suggesting that MH-2/H4N6-originated viruses reassorted with other viruses in LPM. All H4 viruses replicated in mouse lungs without prior adaptation and all viruses replicated and transmitted among ducks. 29-1/H4N2, MH-2/H4N6, and 420-2/H4N6 viruses caused systemic infection in infected ducks. However, most of the viruses were not adapted in chickens. The present results indicate a potential correlation of AIV between LPMs and farms and suggest that active surveillance of AIV in LPM is warranted in China.
10.1038/srep37843
Farm biosecurity practices affecting avian influenza virus circulation in commercial chicken farms in Bangladesh.
One health (Amsterdam, Netherlands)
Avian influenza virus (AIV) is of major concern to livestock, wildlife, and human health. In many countries in the world, including Bangladesh, AIV is endemic in poultry, requiring improving biosecurity. In Bangladesh, we investigated how variation in biosecurity practices in commercial chicken farms affected their AIV infection status to help guide AIV mitigation strategies. We collected pooled fecal swabs from 225 farms and tested the samples for the AIV matrix gene followed by H5, H7, and H9 subtyping using rRT-PCR. We found that 39.6% of chicken farms were AIV positive, with 13% and 14% being positive for subtypes H5 and H9, respectively. Using a generalized linear mixed effects model, we identified as many as 12 significant AIV risk factors. Two major factors promoting AIV risk that cannot be easily addressed in the short term were farm size and the proximity of the farm to a live bird market. However, the other ten significant determinants of AIV risk can be more readily addressed, of which the most important ones were limiting access by visitors (reducing predicted AIV risk from 42 to 6%), isolation and treatment of sick birds (42 to 7%), prohibiting access of vehicles to poultry sheds (38 to 8%), improving hand hygiene (from 42 to 9%), not sharing farm workers across farms (37 to 8%), and limiting access by wild birds to poultry sheds (37 to 8%). Our findings can be applied to developing practical and cost-effective measures that significantly decrease the prevalence of AIV in chicken farms. Notably, in settings with limited resources, such as Bangladesh, these measures can help governments strengthen biosecurity practices in their poultry industry to limit and possibly prevent the spread of AIV.
10.1016/j.onehlt.2024.100681
The role of rodents in avian influenza outbreaks in poultry farms: a review.
Velkers Francisca C,Blokhuis Simon J,Veldhuis Kroeze Edwin J B,Burt Sara A
The veterinary quarterly
Wild migratory birds are associated with global avian influenza virus (AIV) spread. Although direct contact with wild birds and contaminated fomites is unlikely in modern non-free range poultry farms applying biosecurity measures, AIV outbreaks still occur. This suggests involvement of other intermediate factors for virus transmission between wild birds and poultry. This review describes current evidence of the potential role of rodents in AIV transmission from wild birds to poultry and between poultry houses. Rodents can be abundant around poultry houses, share their habitat with waterfowl and can readily enter poultry houses. Survival of AIV from waterfowl in poultry house surroundings and on the coat of rodents suggests that rodents are likely to act as mechanical vector. AIVs can replicate in rodents without adaptation, resulting in high viral titres in lungs and nasal turbinates, virus presence in nasal washes and saliva, and transmission to naïve contact animals. Therefore, active AIV shedding by infected rodents may play a role in transmission to poultry. Further field and experimental studies are needed to provide evidence for a role of rodents in AIV epidemiology. Making poultry houses rodent-proof and the immediate surroundings unattractive for rodents are recommended as preventive measures against possible AIV introduction.
10.1080/01652176.2017.1325537