Low‐pathogenic notifiable avian influenza serosurveillance and the risk of infection in poultry – a critical review of the European Union active surveillance programme (2005–2007)

Abstract

Please cite this paper as: Gonzales et al. (2010) Low‐pathogenic notifiable avian influenza serosurveillance and the risk of infection in poultry – a critical review of the European Union active surveillance programme (2005–2007). Influenza and Other Respiratory Viruses 4(2), 91–99. Background Since 2003, Member States (MS) of the European Union (EU) have implemented serosurveillance programmes for low pathogenic notifiable avian influenza (LPNAI) in poultry. To date, there is the need to evaluate the surveillance activity in order to optimize the programme’s surveillance design. Objectives To evaluate MS sampling operations [sample size and targeted poultry types (PTs)] and its relation with the probability of detection and to estimate the PTs relative risk (RR) of being infected. Methods Reported data of the surveillance carried out from 2005 to 2007 were analyzed using: (i) descriptive indicators to characterize both MS sampling operations and its relation with the probability of detection and the LPNAI epidemiological situation, and (ii) multivariable methods to estimate each PTs RR of being infected. Results Member States sampling a higher sample size than that recommended by the EU had a significantly higher probability of detection. Poultry types with ducks & geese, game‐birds, ratites and “others” had a significant higher RR of being seropositive than chicken categories. The seroprevalence in duck & geese and game‐bird holdings appears to be higher than 5%, which is the EU‐recommended design prevalence (DP), while in chicken and turkey categories the seroprevalence was considerably lower than 5% and with that there is the risk of missing LPNAI seropositive holdings. Conclusion It is recommended that the European Commission discusses with its MS whether the results of our evaluation calls for refinement of the surveillance characteristics such as sampling frequency, the between‐holding DP and MS sampling operation strategies.

Risk based surveillance for early detection of low pathogenic avian influenza outbreaks in layer chickens

“…Outbreaks caused by these LPAIV are notifiable to the World Organisation for Animal Health (OIE). Therefore, Member States (MS) of the European Union (EU) have implemented surveillance programmes (Gonzales et al, 2010), and in the event of detection of a LPAIV, eradication measures are implemented (European Council, 2005). Nevertheless, mutations from LPAI to HPAI virus have occurred (DEFRA, 2008;San Miguel and Sanchez, 2010).…”

“…Current surveillance programmes for LPAI, in the EU, are designed to serologically detect infected flocks while assuming a design prevalence (Gonzales et al, 2010). It is expected that infection is present at a level equal or greater than this intuitively chosen design prevalence (Cannon, 2002).…”

“…However, because of both the assumption that prevalence in an infected flock will always exceed the design prevalence and that the rate of virus introduction is unknown, optimal sampling frequency is not obvious. Since new introductions of LPAIV in poultry in the EU occur on regular basis (Gonzales et al, 2010), sampling frequency is an important variable in surveillance. Hence, a method that could estimate the optimal sampling frequency would help to improve current surveillance regulations.…”

Evolutionary consequences of a decade of vaccination against subtype H6N2 influenza

“…Live bird markets are largely absent and the region is water-scarce (reviewed in Cumming et al, 2015). Other regions, including the European member states and North America but East Asia in particular occasionally report new transmissions of into commercial and backyard gallinaceous poultry of various LPAI strains, including the potentially pathogenic H5 and H7 subtypes (Cheung et al 2007;Gonzales et al 2010;Corrand et al 2012;Krauss et al 2015), but countries have varying levels of competence in preventing these events from becoming established in poultry.…”

Evaluation of ELISA and haemagglutination inhibition as screening tests in serosurveillance for H5/H7 avian influenza in commercial chicken flocks

“…A range of diverse poultry production practices with perceived risks of H5/H7 AIV incursions is considered in different EU countries. These differences influence the extent of flock sampling in national surveillance programmes [17]. The results are published annually [18,19].…”