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This progress report describes the first transmission study in a series of four studies. This long-term study aims to determine whether vaccination under field circumstances can protect layer flocks long term against HPAI H5N1 virus (clade 2.3.4.4b) and reducing within flock transmission (R<1). This transmission study was performed at 8-weeks post vaccination with layer hens which were housed under field circumstances. In addition to the main output, which is assessment of the level of transmission, other variables such as chicken survival, virus shedding, humoral and cellular immune responses were studied to assess the effectiveness of vaccination with VAXXITEK HVT+IBD+H5 vaccine in poultry against HPAI H5N1 virus infection. The estimated R for the control group was 1.3 (95% CI 0.58–2.87) and transmission in the VAXXITEK HVT+IBD+H5 could not be quantified as none of the inoculated chickens became infected. For the analysis, a chicken is considered infected when the following parameters applied: • Virus shedding: when virus was detected for 2 days or longer (≥2 days) with a minimum equivalent titer of ≥Log 101.7 eqEID50/ml by PCR in swabs collected from either choana or cloaca. and • If the chicken survived the challenge, additional parameters were: o a positive NP-ELISA result (after 21 days) and/or o showed an increase of ≥3 log2 in the heterologous HI-titer. This definition is consistent with the definition used in our previous study [1]. In the control groups 9/10 inoculated chickens and 7/10 contact chickens met these criteria and were considered infected. The non-infected inoculated chicken in control group A, was positive for virus shedding, but had no positive serological response. After vaccination with the VAXXITEK HVT+IBD+H5 vaccine, none of the chickens became infected (although 2/10 inoculated chickens were positive for virus shedding). No positive serological results were obtained. In addition, prior to inoculation, the vaccinated chickens had a signif

This progress report describes the first transmission study in a series of four studies. This long-term study aims to determine whether vaccination under field circumstances can protect layer flocks long term against HPAI H5N1 virus (clade 2.3.4.4b) and reducing within flock transmission (R<1). This transmission study was performed at 8-weeks post vaccination with layer hens which were housed under field circumstances. In addition to the main output, which is assessment of the level of transmission, other variables such as chicken survival, virus shedding, humoral and cellular immune responses were studied to assess the effectiveness of vaccination with VECTORMUNE® AI vaccine in poultry against HPAI H5N1 virus infection. The estimated R for the control group was 1.3 (95% CI 0.58–2.87) and transmission in the VECTORMUNE® AI could not be quantified as none of the inoculated chickens became infected. For the analysis, a chicken is considered infected when the following parameters applied: • Virus shedding: when virus was detected for 2 days or longer (≥2 days) with a minimum equivalent titer of ≥Log 101.7 eqEID50/ml by PCR in swabs collected from either choana or cloaca. and • If the chicken survived the challenge, additional parameters were: o a positive NP-ELISA result (after 21 days) and/or o showed an increase of ≥3 log2 in the heterologous HI-titer. This definition is consistent with the definition used in our previous study [1]. In the control groups 9/10 inoculated chickens and 7/10 contact chickens met these criteria and were considered infected. The non-infected inoculated chicken in control group A, was positive for virus shedding, but had no positive serological response. After vaccination with the VECTORMUNE® AI vaccine, none of the chickens became infected (although two inoculated chickens were positive for virus shedding). No positive serological results were obtained, (except an increased HI-titer of log2 ≥3 for 2 chickens). In addition, prior to inocula

In het afgelopen decennium zijn er in Nederland een groot aantal uitbraken geweest van vogelgriep (aviaire influenza, AI) op pluimveebedrijven. Bij een verdenking van vogelgriep in pluimvee worden monsters door de NVWA op locatie genomen en vervolgens door het nationaal referentielaboratorium in Lelystad getest met PCR. Als er veel gelijktijdige verdenkingen zijn, kan een eenvoudige sneltest op locatie helpen om prioriteiten te stellen en zo beschikbare middelen efficiënt in te zetten. Er zijn commerciële sneltesten verkrijgbaar voor de detectie van het influenzavirus in monsters afgenomen bij mensen en pluimvee. Een aantal van deze sneltesten is in de voorgaande studie ‘Inventarisatie van sneltesten voor vogelgriep’ onderzocht op gevoeligheid en gebruiksgemak. In de huidige studie zijn een aantal prestatiekenmerken van drie sneltesten (Clungene, Anigen en Biopanda) uitgebreider onderzocht. De resultaten laten het volgende zien. Voor luchtpijp- en cloaca-monsters van kippen geïnfecteerd met AI (n=16) komt de Clungene sneltest voor 93% overeen met de PCR-resultaten. Voor met vogelgriep geïnfecteerde vleeseenden (n=8) is dat 100% voor luchtpijp-monsters, maar slechts 50% voor cloaca-monsters. Voor de sneltesten van Anigen en Biopanda, die beiden getest zijn met een kleiner aantal geïnfecteerde kippen (n=8) en vleeseenden (n=4), variëren de overeenkomsten met PCR van 71% tot 100% voor kippen, en resp. 100% en 0% voor luchtpijp- en cloaca-swabs van vleeseenden. Aanvullend is voor de Clungene sneltest berekend dat 90% van de PCR-positieve veldmonsters van de afgelopen twee jaar correct als positief zouden zijn geïdentificeerd. Voor keel- en cloaca-swabs van vogelgriep-negatief pluimvee (20 kippen en 20 vleeseenden) is de Clungene sneltest in 94% van de gevallen correct negatief. De Biopanda en Anigen sneltesten, beiden getest met 4 kippen en 4 vleeseenden, zijn correct negatief met 100% van de geteste monsters. Onder laboratoriumcondities tonen alle drie de snelte