Blood samples sent to the department also show cause for suspicion of ILT at another farm located in Sarpsborg. There are no reports of contact between the two herds.

However, in both cases, samples were submitted to the National Veterinary Institute because respiratory symptoms were detected in chickens.

Last Monday (8 April), the Institute noted significant inflammatory changes in the trachea of two dead birds. On 12 April, the Department of Pathology detected microscopic abnormalities in the mucosa of the respiratory tract characteristic of ILT.

Through microscopic examination, an acute phase of ILT showed characteristic changes. These can be difficult to detect in later stages.

On 10 April, a hobby flock in Sarpsborg sent blood samples to the National Veterinary Institute due to respiratory symptoms. The samples showed antibodies against the ILT virus and also against the virus that causes infectious bronchitis (IB).

The presence of the antibodies in the blood proved that the birds had been exposed to ILT virus earlier in life. However, it is not possible to determine whether the bird was infected at the time the blood sample was taken.

Both ILT and IB are infectious respiratory diseases in poultry. In Norway, it is mainly hobby flocks that are affected, but there have been cases of IB in laying hens.

Chickens and pheasants are regarded as the only poultry species susceptible to ILT, while IB affects only hens. ILT has no known impact on public health.