TY - JOUR

T1 - Vaccination of poultry against highly pathogenic avian influenza – Part 2. Surveillance and mitigation measures

AU - EFSA Panel on Animal Health and Animal Welfare, null

AU - European Union Reference Laboratory for Avian Influenza, null

AU - Nielsen, Søren Saxmose

AU - Alvarez, Julio

AU - Bicout, Dominique Joseph

AU - Calistri, Paolo

AU - Canali, Elisabetta

AU - Drewe, Julian Ashley

AU - Garin-Bastuji, Bruno

AU - Gortázar, Christian

AU - Herskin, Mette S.

AU - Michel, Virginie

AU - Miranda Chueca, Miguel Ángel

AU - Padalino, Barbara

AU - Roberts, Helen Clare

AU - Spoolder, Hans

AU - Stahl, Karl

AU - Velarde, Antonio

AU - Viltrop, Arvo

AU - Winckler, Christoph

AU - Bortolami, Alessio

AU - Guinat, Claire

AU - Harder, Timm

AU - Stegeman, Arjan

AU - Terregino, Calogero

AU - Lanfranchi, Barbara

AU - Preite, Ludovica

AU - Aznar, Inma

AU - Broglia, Alessandro

AU - Baldinelli, Francesca

AU - Gonzales Rojas, Jose Luis

PY - 2024/4/18

Y1 - 2024/4/18

N2 - Selecting appropriate diagnostic methods that take account of the type of vaccine used is important when implementing a vaccination programme against highly pathogenic avian influenza (HPAI). If vaccination is effective, a decreased viral load is expected in the samples used for diagnosis, making molecular methods with high sensitivity the best choice. Although serological methods can be reasonably sensitive, they may produce results that are difficult to interpret. In addition to routine molecular monitoring, it is recommended to conduct viral isolation, genetic sequencing and phenotypic characterisation of any HPAI virus detected in vaccinated flocks to detect escape mutants early. Following emergency vaccination, various surveillance options based on virological testing of dead birds (?bucket sampling?) at defined intervals were assessed to be effective for early detection of HPAIV and prove disease freedom in vaccinated populations. For ducks, virological or serological testing of live birds was assessed as an effective strategy. This surveillance could be also applied in the peri-vaccination zone on vaccinated establishments, while maintaining passive surveillance in unvaccinated chicken layers and turkeys, and weekly bucket sampling in unvaccinated ducks. To demonstrate disease freedom with >?99% confidence and to detect HPAI virus sufficiently early following preventive vaccination, monthly virological testing of all dead birds up to 15 per flock, coupled with passive surveillance in both vaccinated and unvaccinated flocks, is recommended. Reducing the sampling intervals increases the sensitivity of early detection up to 100%. To enable the safe movement of vaccinated poultry during emergency vaccination, laboratory examinations in the 72?h prior to the movement can be considered as a risk mitigation measure, in addition to clinical inspection; sampling results from existing surveillance activities carried out in these 72?h could be used. In this Opinion, several schemes are recommended to enable the safe movement of vaccinated poultry following preventive vaccination.

AB - Selecting appropriate diagnostic methods that take account of the type of vaccine used is important when implementing a vaccination programme against highly pathogenic avian influenza (HPAI). If vaccination is effective, a decreased viral load is expected in the samples used for diagnosis, making molecular methods with high sensitivity the best choice. Although serological methods can be reasonably sensitive, they may produce results that are difficult to interpret. In addition to routine molecular monitoring, it is recommended to conduct viral isolation, genetic sequencing and phenotypic characterisation of any HPAI virus detected in vaccinated flocks to detect escape mutants early. Following emergency vaccination, various surveillance options based on virological testing of dead birds (?bucket sampling?) at defined intervals were assessed to be effective for early detection of HPAIV and prove disease freedom in vaccinated populations. For ducks, virological or serological testing of live birds was assessed as an effective strategy. This surveillance could be also applied in the peri-vaccination zone on vaccinated establishments, while maintaining passive surveillance in unvaccinated chicken layers and turkeys, and weekly bucket sampling in unvaccinated ducks. To demonstrate disease freedom with >?99% confidence and to detect HPAI virus sufficiently early following preventive vaccination, monthly virological testing of all dead birds up to 15 per flock, coupled with passive surveillance in both vaccinated and unvaccinated flocks, is recommended. Reducing the sampling intervals increases the sensitivity of early detection up to 100%. To enable the safe movement of vaccinated poultry during emergency vaccination, laboratory examinations in the 72?h prior to the movement can be considered as a risk mitigation measure, in addition to clinical inspection; sampling results from existing surveillance activities carried out in these 72?h could be used. In this Opinion, several schemes are recommended to enable the safe movement of vaccinated poultry following preventive vaccination.

KW - avian influenza transmission

KW - highly pathogenic avian influenza (HPAI)

KW - poultry

KW - surveillance

KW - surveillance strategies

U2 - 10.2903/j.efsa.2024.8755

DO - 10.2903/j.efsa.2024.8755

M3 - Journal article

C2 - 38638555

VL - 22

SP - 1

EP - 70

JO - E F S A Journal

JF - E F S A Journal

SN - 1831-4732

IS - 4

M1 - e8755

ER -