Assessing the probability of introduction and spread of avian influenza (AI) virus in commercial Australian poultry operations using an expert opinion elicitation

Singh, Mini; Toribio, Jenny‐Ann L.M.L.; Scott, Angela Bullanday; Groves, Peter J.; Barnes, Belinda; Glass, Kathryn; Moloney, Barbara; Hernández‐Jover, Marta

doi:10.1371/journal.pone.0193730

Cited by 15 publications

(24 citation statements)

References 57 publications

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“…environmental conditions, climate, presence of wild animals, etc.) 16,23 . Based on these premises, the presence of segregated poultry companies should represent an effective obstacle to viral shedding and the obtained results partially confirm these evidence.…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, the co-circulation of field and live attenuated vaccines could enhance the likelihood of recombination and the vaccine induced immunity could promote and/or guide viral evolution 8,9 . Biosecurity measures and the proper understanding of the factors influencing viral spread are thus of primary importance. The risk factors of virus introduction in a farm have been investigated in several studies, and include transport of live poultry, species and productive category, dominant winds 10,11 , sharing of personnel, fomites and means of transportation [12][13][14][15][16] . Other routes of transmission are summarized under the umbrella of 'contiguous spread' .…”

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confidence: 99%

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Phylodynamic analysis and evaluation of the balance between anthropic and environmental factors affecting IBV spreading among Italian poultry farms

Franzo

Tucciarone

Moreno

et al. 2020

Sci Rep

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Infectious bronchitis virus (IBV) control is mainly based on wide vaccine administration.Although effective, its efficacy is not absolute, the viral circulation is not prevented and some side effects cannot be denied. Despite this, the determinants of IBV epidemiology and the factors affecting its circulation are still largely unknown and poorly investigated. In the present study, 361 IBV QX (the most relevant field genotype in Italy) sequences were obtained between 2012 and 2016 from the two main Italian integrated poultry companies. Several biostatistical and bioinformatics approaches were used to reconstruct the history of the QX genotype in Italy and to assess the effect of different environmental, climatic and social factors on its spreading patterns. Moreover, two structured coalescent models were considered in order to investigate if an actual compartmentalization occurs between the two integrated poultry companies and the role of a third "ghost" deme, representative of minor industrial poultry companies and the rural sector. The obtained results suggest that the integration of the poultry companies is an effective barrier against IBV spreading, since the strains sampled from the two companies formed two essentially-independent clades. Remarkably, the only exceptions were represented by farms located in the high densely populated poultry area of Northern Italy. The inclusion of a third deme in the model revealed the likely role of other poultry companies and rural farms (particularly concentrated in Northern Italy) as sources of strain introduction into one of the major poultry companies, whose farms are mainly located in the high densely populated poultry area of Northern Italy. Accordingly, when the effect of different environmental and urban parameters on IBV geographic spreading was investigated, no factor seems to contribute to IBV dispersal velocity, being poultry population density the only exception. Finally, the different viral population pattern observed in the two companies over the same time period supports the pivotal role of management and control strategies on IBV epidemiology. Overall, the present study results stress the crucial relevance of human action rather than environmental factors, highlighting the direct benefits that could derive from improved management and organization of the poultry sector on a larger scale. Infectious bronchitis virus (IBV)is currently classified in the species Avian coronavirus, genus Gammacoronavirus, family Coronaviridae (https://talk.ictvonline.org/). The viral genome is about 27Kb long and encodes different non-structural, accessory and structural proteins. Among those, the structural spike protein is by far the most extensively studied, because of its role in viral attachment, cell tropism and immunity 1 . Additionally, the current

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Phylodynamic analysis and evaluation of the balance between anthropic and environmental factors affecting IBV spreading among Italian poultry farms

Franzo

Tucciarone

Moreno

et al. 2020

Sci Rep

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“…In addition, input values were also obtained from scientific literature. An expert opinion workshop was also held to obtain input values that were largely unknown or undescribed in the scientific literature ( 22 ).…”

Section: Methodsmentioning

confidence: 99%

“…The second round of estimates for each question for all experts was then combined using a weighting factor depending on their respective level of expertise relevant to each question, in a discrete distribution. More details on the expert elicitation process and the outcomes of the study can be found in the study by Singh et al ( 22 ).…”

Section: Methodsmentioning

confidence: 99%

Low- and High-Pathogenic Avian Influenza H5 and H7 Spread Risk Assessment Within and Between Australian Commercial Chicken Farms

et al. 2018

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This study quantified and compared the probability of avian influenza (AI) spread within and between Australian commercial chicken farms via specified spread pathways using scenario tree mathematical modeling. Input values for the models were sourced from scientific literature, expert opinion, and a farm survey conducted during 2015 and 2016 on Australian commercial chicken farms located in New South Wales (NSW) and Queensland. Outputs from the models indicate that the probability of no establishment of infection in a shed is the most likely end-point after exposure and infection of low-pathogenic avian influenza (LPAI) in one chicken for all farm types (non-free range meat chicken, free range meat chicken, cage layer, barn layer, and free range layer farms). If LPAI infection is established in a shed, LPAI is more likely to spread to other sheds and beyond the index farm due to a relatively low probability of detection and reporting during LPAI infection compared to high-pathogenic avian influenza (HPAI) infection. Among farm types, the median probability for HPAI spread between sheds and between farms is higher for layer farms (0.0019, 0.0016, and 0.0031 for cage, barn, and free range layer, respectively) than meat chicken farms (0.00025 and 0.00043 for barn and free range meat chicken, respectively) due to a higher probability of mutation in layer birds, which relates to their longer production cycle. The pathway of LPAI spread between sheds with the highest average median probability was spread via equipment (0.015; 5–95%, 0.0058–0.036) and for HPAI spread between farms, the pathway with the highest average median probability was spread via egg trays (3.70 × 10−5; 5–95%, 1.47 × 10−6–0.00034). As the spread model did not explicitly consider volume and frequency of the spread pathways, these results provide a comparison of spread probabilities per pathway. These findings highlight the importance of performing biosecurity practices to limit spread of the AI virus. The models can be updated as new information on the mechanisms of the AI virus and on the volume and frequency of movements shed-to-shed and of movements between commercial chicken farms becomes available.

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“…Experts have estimated the probability of LPAI introduction to free range and conventional meat chicken and layer flocks by contact with wild birds directly and indirectly [17] without the benefit of objective data.…”

Section: Australia Is a Relatively Isolated Island Continent And Not mentioning

confidence: 99%

Identifying and managing pathways of AI transmission by wild birds on meat chicken farms in eastern Australia

Atzeni¹,

Fielder²,

Dunlop

et al. 2020

Preprint

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Conjecture surrounds the reservoir and bridge species potentially involved in introducing, maintaining and transmitting avian influenza (AI) on Australian meat chicken farms. This is mainly due to a lack of AI prevalence data and in-depth understanding of wild bird ecology on farms and across regions. For risk assessment purposes, we identified candidate species likely to be involved in AI maintenance and transmission during 68 bird surveys conducted across ten commercial meat chicken farms from Winter 2016 to Summer 2018 in southeastern Queensland. Using an AI-risk classification processes described in this paper, we speculate that 57 of the 139 species recorded in and around production facilities and nearby water bodies pose a medium to high risk, particularly on free range farms. On the farms with permanent waterbodies, resident and semi-resident dabbling ducks (Genus Anas ) could maintain AI indefinitely on-site, creating opportunities for these species and several bridge species to potentially infect poultry by being a vector between the dam/water habitat and poultry facilities. We suggest that other types of wild birds that may be involved in AI transmission including nomadic waterfowl, grazing ducks (Australian Wood Ducks and Plumed Whistling-duck), Waterhens, Lapwings, resident scavengers (corvids, ibis), birds of prey and mud nests builders (e.g. Fairy Martins). Disrupting AI maintenance cycles on farm dams would reduce the chances of transmission of environmental AI by potential bridge species. This may be achievable by proactively preventing higher risk waterfowl becoming resident and habituated on farms and deterring potential bridge species from accessing poultry houses. Targeted AI surveillance of suspected bridge species is required to determine the real risk. Ideally, this should occur on non-commercial poultry farms where AI transmission to poultry can be objectively investigated.

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Assessing the probability of introduction and spread of avian influenza (AI) virus in commercial Australian poultry operations using an expert opinion elicitation

Cited by 15 publications

References 57 publications

Phylodynamic analysis and evaluation of the balance between anthropic and environmental factors affecting IBV spreading among Italian poultry farms

Phylodynamic analysis and evaluation of the balance between anthropic and environmental factors affecting IBV spreading among Italian poultry farms

Low- and High-Pathogenic Avian Influenza H5 and H7 Spread Risk Assessment Within and Between Australian Commercial Chicken Farms

Identifying and managing pathways of AI transmission by wild birds on meat chicken farms in eastern Australia

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