ILT and ART in poultry

Updated 18.06.2026

Infectious laryngotracheitis (ILT) has not been detected in Norwegian commercial poultry flocks since 1971, but is occasionally observed in backyard poultry flocks. Avian rhinotracheitis (ART), also known as turkey rhinotracheitis (TRT) in turkeys, has never been detected in Norwegian turkey flocks.

The purpose of the surveillance program is to document that Norwegian commercial poultry flocks of chickens are free from ILT and that commercial turkey flocks are free from ART, as well as to help maintain this status.

Background

ILT is a serious, contagious respiratory disease in chickens caused by a herpesvirus. The disease is widespread in many parts of the world, including most European countries. ILT has not been diagnosed in commercial poultry flocks in Norway since 1971, but is sporadically detected in backyard flocks.

ART is a viral disease affecting the upper respiratory tract in poultry. The disease is caused by avian metapneumovirus and is widespread globally and in most European countries. In the early 2000s, antibodies against the virus causing ART were detected in Norwegian broiler and layer flocks. The clinical significance of the infection was uncertain, and chickens were therefore excluded from the surveillance program for ART in 2005. ART, also known as TRT in turkeys, has never been detected in turkeys in Norway.

2025

Surveillance for infectious laryngotracheitis (ILT) in chickens in 2025 did not detect antibodies against gallid herpesvirus 1 (infectious laryngotracheitis virus, ILTV). Surveillance for avian rhinotracheitis (ART) in turkeys identified a limited number of samples with positive reactions for avian metapneumovirus (aMPV). However, follow-up testing and overall assessment indicated that these represented false positive or non-specific reactions. Consequently, all turkey flocks included in the surveillance programme were considered negative for ART.