14 November 2026
Researchers at the Friedrich-Loeffler-Institut (FLI) report that Newcastle disease virus (NDV) of genotype VII.1.1 has infected vaccinated commercial poultry in Germany for the first time in decades. Since 2012, genotype VII viruses have driven a panzootic across Asia and the Middle East. More recently, subgenotype VII.1.1 has spread across the Russian Federation and into Eastern Europe, reaching Poland by 2024. Within the European Union, Newcastle disease (ND) is classified as a Category A disease, meaning that outbreaks trigger mandatory culling of infected holdings and the establishment of strict restriction zones. In Germany, which had been considered free of ND for more than 30 years, vaccination against the disease is legally mandated for all chicken and turkey flocks as a preventive measure.
Between February and May 2026, Germany recorded 65 outbreaks involving the VII.1.1 subgenotype. Of these, 55 occurred in commercial holdings (28 layer, 17 broiler, 7 breeder, and 3 turkey flocks), while the remaining 10 affected non-commercial backyard flocks.
An epidemiological analysis led by the FLI revealed that the outbreaks were concentrated primarily in the German states of Brandenburg and Bavaria. Genomic sequencing confirmed that the viruses possessed a polybasic F protein cleavage site and were closely related to strains circulating in Eastern Europe.
All 55 affected commercial holdings had been vaccinated against ND, in compliance with German legislation. Even broiler flocks that had received booster vaccinations just days or weeks before the initial suspicion of infection were successfully infected. Clinical manifestations varied considerably. While some birds exhibited classical neurological signs, such as torticollis, others showed gastrointestinal or respiratory signs, while some flocks remained largely asymptomatic. Mortality rates recorded before official culling did not reflect the presence of a highly virulent virus. Median pre-culling mortality was exceptionally low: just 0.98% in broilers (with rates reaching up to 6.67%) and only 0.11% in layers. Production records indicated that the earliest warning signs in layer flocks were a sudden decline in egg production accompanied by a slight increase in mortality.
Although genotype II ND vaccines are highly effective at preventing severe clinical disease and high mortality, they do not induce "sterile immunity." Consequently, they cannot completely prevent infection or viral shedding, allowing genotype VII.1.1 viruses to circulate and spread into the environment. Vaccination also does not necessarily prevent declines in egg production. Thus, highly virulent NDV can circulate subclinically within vaccinated flocks, potentially delaying detection and facilitating further spread. Of particular concern, 33% of infected commercial holdings (18 out of 55) were not identified through farmers' clinical suspicion but were detected through active surveillance in restriction zones, contact tracing, or routine monitoring.
These findings highlight the need to evaluate homologous Newcastle disease vaccines targeting the emerging genotype VII.1.1 viruses circulating in Europe.
Bergmann, H., Rudovsky, A., Grund, C., et al. (2026). Outbreaks of Newcastle Disease Virus Genotype VII.1.1 in Vaccinated Commercial Poultry, Germany, 2026. bioRxiv. Preprint.
