Newcastle Disease: Overview and Current Spread in Europe

European veterinary authorities are mobilizing to contain a significant wave of Newcastle Disease Virus (NDV) outbreaks, with Poland identified as the current epicenter of the spread.

Since the beginning of 2026, Polish officials have confirmed 28 distinct outbreak sites. The severity of the situation led authorities to cull more than 500,000 birds following the detection of the virus at two major commercial broiler farms.

Vaccination Gaps and Viral Spread

Diagnostic reports have highlighted a critical vulnerability in flocks that had reportedly undergone full vaccination protocols. Serological testing on broiler farms in Poland revealed antibody titers that were significantly below the threshold required for clinical protection.

Reports indicate the primary cause of this vulnerability is suboptimal vaccine administration rather than primary vaccine failure. This execution gap has left large avian populations immunologically naive despite official vaccination records.

Outbreaks Across Europe

The spread of the virus has extended across several European nations. In Germany, 10 outbreaks were documented as of mid-March 2026, involving nine laying hen operations and one turkey flock.

Spain confirmed a new outbreak on March 9, 2026, at a laying hen farm in Terrateig, located in the Vall d’Albaida region of Valencia. The infection affected one building housing approximately 27,000 birds, all 23 weeks old. This event marked the sixth outbreak in Spain for the season and occurred in a surveillance area where restrictions had been lifted in February 2026.

In the United Kingdom, the Department for Environment, Food & Rural Affairs (DEFRA) and the National Farmers’ Union (NFU) issued an urgent risk assessment in response to the escalating viral pressure in Continental Europe.

Medical and Scientific Overview of Newcastle Disease

Newcastle disease (ND) is a highly contagious and severe worldwide disease affecting birds, caused by virulent strains of avian paramyxovirus type 1. In its highly pathogenic form, We see a listed disease by the World Organisation for Animal Health (WOAH) and must be reported.

The disease manifests in five distinct forms:

• Velogenic viscerotrophic
• Velogenic neutrotropic
• Mesogenic
• Lentogenic
• Asymptomatic enteric

Lentogenic strains are widespread but typically remain asymptomatic and do not cause poultry outbreaks. However, highly pathogenic strains typically manifest as severe respiratory disease, depression, nervousness, and diarrhea.

Because the clinical picture of Newcastle disease is very similar to bird flu, laboratory tests are required to confirm a diagnosis.

Human Health Implications

While primarily an avian disease, Newcastle disease is a mild zoonosis. In humans, the infection can cause conjunctivitis, though the condition is usually mild and self-limiting.