A review of estimated transmission parameters for the spread of avian influenza viruses

Kirkeby, Carsten; Ward, Michael P.

doi:10.1111/tbed.14675

Cited by 6 publications

(20 citation statements)

References 39 publications

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“…We simulated the following scenarios, using the estimates described above: (1) turkeys with LPAI; (2) turkeys with HPAI; (3) chickens with LPAI; (4) chickens with HPAI; (5) chickens with H5N1; (6) chickens with H5N2; and for H7; (7) chickens with H7N1; (8) chickens with H7N3; and (9) chickens with H7N7 (summarized in Figures 2 and 3). For scenarios with chickens and H5N2, H7N3 and H7N7, no estimates for the period of latency were available (Kirkeby & Ward, 2022), and the default fixed latency period of 1 day was used in these simulations. The predicted numbers of infected birds, days of peak infection and days of disease fadeout for each scenario are shown in Table 1.…”

Section: Resultsmentioning

confidence: 99%

“…Estimates for the transmission rate (β), latency and duration of infection were obtained from the data cited in a previous study (Kirkeby & Ward, 2022). We only included estimates from experiments in which the numbers of animals and the 95% CI for each of the variables were reported.…”

Section: Methodsmentioning

confidence: 99%

“…All other subtypes are regarded as LPAIVs. HPAIVs are associated with high mortality and a reduced basic reproduction rate (R 0 ), because infected animals have a shorter lifespan (and therefore a reduced period of infectiousness) compared to LPAI (Kirkeby & Ward, 2022).…”

Section: Introductionmentioning

confidence: 99%

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Are all avian influenza outbreaks in poultry the same? The predicted impact of poultry species and virus subtype

Kirkeby,

Boklund,

Larsen

et al. 2024

Zoonoses and Public Health

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AimsOutbreaks of avian influenza in poultry farms are currently increasing in frequency, with devastating consequences for animal welfare, farmers and supply chains. Some studies have documented the direct spread of the avian influenza virus between farms. Prevention of spread between farms relies on biosecurity surveillance and control measures. However, the evolution of an outbreak on a farm might vary depending on the virus strain and poultry species involved; this would have important implications for surveillance systems, epidemiological investigations and control measures.Methods and ResultsIn this study, we utilized existing parameter estimates from the literature to evaluate the predicted course of an epidemic in a standard poultry flock with 10,000 birds. We used a stochastic SEIR simulation model to simulate outbreaks in different species and with different virus subtypes. The simulations predicted large differences in the duration and severity of outbreaks, depending on the virus subtypes. For both turkeys and chickens, outbreaks with HPAI were of shorter duration than outbreaks with LPAI. In outbreaks involving the infection of chickens with different virus subtypes, the shortest epidemic involved H7N7 and HPAIV H5N1 (median duration of 9 and 17 days, respectively) and the longest involved H5N2 (median duration of 68 days). The most severe outbreaks (number of chickens infected) were predicted for H5N1, H7N1 and H7N3 virus subtypes, and the least severe for H5N2 and H7N7, in which outbreaks for the latter subtype were predicted to develop most slowly.ConclusionsThese simulation results suggest that surveillance of certain subtypes of avian influenza virus, in chicken flocks in particular, needs to be sensitive and timely if infection is to be detected with sufficient time to implement control measures. The variability in the predictions highlights that avian influenza outbreaks are different in severity, speed and duration, so surveillance and disease response need to be nuanced and fit the specific context of poultry species and virus subtypes.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Are all avian influenza outbreaks in poultry the same? The predicted impact of poultry species and virus subtype

Kirkeby,

Boklund,

Larsen

et al. 2024

Zoonoses and Public Health

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“…Indeed, previous efforts have demonstrated that Anatidae are competent vectors for avian influenza due to their high shedding rates [31,32], long duration of infection [33,34], and comparatively high prevalence in the wild [35,36]. However, while previous studies have provided us with valuable information on the general response to infection for Anseriformes, the importance of these species to the transmission of AIVs both across space [30,37] and across the wild waterfowl – domestic poultry interface [18,38] suggests that future work with these species could aim to develop better estimates of parameters needed for transmission risk modeling [39] such as minimum infectious dose which is currently only rarely included [40,41]. Similarly, the continued high representation of Anatidae in mortality events and surveillance sampling [20] emphasizes the importance of studies focused on including emerging viral strains to inform possible outcomes prior to outbreak events and to maintain current data.…”

Section: Discussionmentioning

confidence: 99%

A systematic review of laboratory investigations into the pathogenesis of avian influenza viruses in wild avifauna of North America

Gonnerman,

Leyson,

Sullivan

et al. 2024

Preprint

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The lack of consolidated information regarding response of wild bird species to infection with avian influenza virus (AIV) is a challenge to both conservation managers and researchers alike, with related sectors also impacted, such as public health and commercial poultry. Using two independent searches, we reviewed published literature for studies describing wild bird species experimentally infected with avian influenza to assess host species' relative susceptibility to AIVs. Additionally, we summarize broad scale parameters for elements such as shedding duration and minimum infectious dose that can be used in transmission modeling efforts. Our synthesis shows that waterfowl (i.e., Anatidae) comprise the vast majority of published AIV pathobiology studies, whereas gulls and passerines were less represented in research despite evidence that they also are susceptible and contribute to highly pathogenic avian influenza disease dynamics. This study represents the first comprehensive effort to compile available literature regarding the pathobiology of AIVs in all wild birds in over a decade. This database can now serve as a tool to all researchers, providing generalized estimates of pathobiology parameters for a variety of wild avian families and an opportunity to critically examine and assess what is known and identify where further insight is needed.

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“…Reviews conducted so far on avian influenza have focused on virological and clinical aspects [ 24 , 25 ] or on risk factors [ 26 – 28 ], including transmission routes [ 29 , 30 ]. Two recent studies reviewed transmission parameter values based on experimental studies [ 31 ] and on both experimental and field studies [ 32 ], but to the best of our knowledge no comprehensive analysis of mechanistic models has been undertaken. To fill this gap, we conducted a systematic review of mechanistic models applied to avian influenza in poultry to (i) describe the mechanistic models used and their epidemiological context, (ii) list AIV transmission parameters, and (iii) provide insights on avian influenza transmission and the impact of control measures.…”

Section: Introductionmentioning

confidence: 99%

A systematic review of mechanistic models used to study avian influenza virus transmission and control

Lambert,

Bauzile,

Mugnier

et al. 2023

Vet Res

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The global spread of avian influenza A viruses in domestic birds is causing increasing socioeconomic devastation. Various mechanistic models have been developed to better understand avian influenza transmission and evaluate the effectiveness of control measures in mitigating the socioeconomic losses caused by these viruses. However, the results of models of avian influenza transmission and control have not yet been subject to a comprehensive review. Such a review could help inform policy makers and guide future modeling work. To help fill this gap, we conducted a systematic review of the mechanistic models that have been applied to field outbreaks. Our three objectives were to: (1) describe the type of models and their epidemiological context, (2) list estimates of commonly used parameters of low pathogenicity and highly pathogenic avian influenza transmission, and (3) review the characteristics of avian influenza transmission and the efficacy of control strategies according to the mechanistic models. We reviewed a total of 46 articles. Of these, 26 articles estimated parameters by fitting the model to data, one evaluated the effectiveness of control strategies, and 19 did both. Values of the between-individual reproduction number ranged widely: from 2.18 to 86 for highly pathogenic avian influenza viruses, and from 4.7 to 45.9 for low pathogenicity avian influenza viruses, depending on epidemiological settings, virus subtypes and host species. Other parameters, such as the durations of the latent and infectious periods, were often taken from the literature, limiting the models’ potential insights. Concerning control strategies, many models evaluated culling (n = 15), while vaccination received less attention (n = 6). According to the articles reviewed, optimal control strategies varied between virus subtypes and local conditions, and depended on the overall objective of the intervention. For instance, vaccination was optimal when the objective was to limit the overall number of culled flocks. In contrast, pre-emptive culling was preferred for reducing the size and duration of an epidemic. Early implementation consistently improved the overall efficacy of interventions, highlighting the need for effective surveillance and epidemic preparedness.

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A review of estimated transmission parameters for the spread of avian influenza viruses

Cited by 6 publications

References 39 publications

Are all avian influenza outbreaks in poultry the same? The predicted impact of poultry species and virus subtype

Are all avian influenza outbreaks in poultry the same? The predicted impact of poultry species and virus subtype

A systematic review of laboratory investigations into the pathogenesis of avian influenza viruses in wild avifauna of North America

A systematic review of mechanistic models used to study avian influenza virus transmission and control

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