Estimating the introduction time of highly pathogenic avian influenza into poultry flocks

Abstract

The estimation of farm-specific time windows for the introduction of highly-pathogenic avian influenza (HPAI) virus can be used to increase the efficiency of disease control measures such as contact tracing and may help to identify risk factors for virus introduction. The aims of this research are to (1) develop and test an accurate approach for estimating farm-specific virus introduction windows and (2) evaluate this approach by applying it to 11 outbreaks of HPAI (H5N8) on Dutch commercial poultry farms during the years 2014 and 2016. We used a stochastic simulation model with susceptible, infectious and recovered/removed disease stages to generate distributions for the period from virus introduction to detection. The model was parameterized using data from the literature, except for the within-flock transmission rate, which was estimated from disease-induced mortality data using two newly developed methods that describe HPAI outbreaks using either a deterministic model (A) or a stochastic approach (B). Model testing using simulated outbreaks showed that both method A and B performed well. Application to field data showed that method A could be successfully applied to 8 out of 11 HPAI H5N8 outbreaks and is the most generally applicable one, when data on disease-induced mortality is scarce.

Investigation into a Superspreading Event of the German 2020–2021 Avian Influenza Epidemic

“…Data of [ 12 ] referring to the year 2016 imply, however, that the latent period may be as short as one day. The time span from infection to death was chosen as 4.5 days, i.e., the latent period plus an infectious period of 2.5 days based on a literature review of [ 13 ] concerning the situation in the year 2014. The investigations of [ 12 ] in the year 2016 suggest a markedly shorter infectious period.…”

Exploiting Pan Influenza A and Pan Influenza B Pseudotype Libraries for Efficient Vaccine Antigen Selection

“…Only influenza A (IAV) and influenza B (IBV) viruses are endemic in the global human population, rapidly spreading around the world in seasonal epidemics, imposing considerable economic burden and death [7,8]. From its wild bird reservoir, IAV is able to transmit from domestic poultry [9], which is the gateway to infection of mammals, most notably, swine and humans [10]. IBV's natural reservoir is humans, however there have been reports of infection in seals [11][12][13], alluding to its potential to cause disease in other species.…”

“…Whilst antigenic divergence both within and across HA subtypes exists, the HA stem domain is more conserved and, although not as immunogenic as the head domain [ 17 , 22 ], is increasingly being explored as a candidate for universal influenza vaccines [ 22 , 41 ]. As such, the importance of studying HA structure and function and monitoring antigenic changes within HA is critical to understanding antigenic evolution, defining the most antigenically relevant antigens for annual human vaccination programs [ 42 , 43 ], determining potent universal vaccine targets [ 44 , 45 ], developing vaccines for veterinary use [ 9 , 46 ], and improving influenza diagnosis and therapeutic interventions [ 47 , 48 , 49 , 50 ].…”

Establishment of pan-Influenza A (H1-H18) and pan-Influenza B (pre-split, Vic/Yam) Pseudotype Libraries for efficient vaccine antigen selection

“…Only influenza A (IAV) and influenza B (IBV) viruses are endemic in the global human population, rapidly spreading around the world in seasonal epidemics; imposing considerable economic burden and death [6, 7]. From its wild bird reservoir, IAV is able to transmit from domestic poultry [8], which is the gateway to infection of mammals, most notably, swine and humans [9]. IBV’s natural reservoir is humans, however there have been reports of infection in seals [10, 11], alluding to its potential to cause disease in other species.…”

“…Whilst antigenic divergence both within and across HA subtypes exists,the HA stem domain is more conserved and although not as immunogenic as the head domain [15, 20], is increasingly being explored as a candidate for universal influenza vaccines [20, 39]. As such, the importance of studying HA structure and function and monitoring antigenic changes within HA is critical to: understanding antigenic evolution; defining the most antigenically relevant antigens for annual human vaccination programs [40, 41], determining potent universal vaccine targets [42, 43], developing vaccines for veterinary use [8, 44], and improving influenza diagnosis and therapeutic interventions [45-48].…”