Bird flu (H5N1) detected in a fox with neurological symptoms

January 7, 2022

Wageningen Bioveterinary Research (WBVR) has identified avian influenza in a fox from Dorst (in the province of Brabant). The virus has been identified as highly pathogenic type H5N1 avian influenza. The fox was found in early December and showed neurological symptoms such as walking in circles and falling over. The animal was probably blind as well. The fox was taken in by an animal shelter and was euthanised there due to the severe symptoms.

WBVR subsequently conducted further research into the genetic composition of the fox virus. The virus was found to be very similar to those found in infected wild birds in the Netherlands. It is therefore plausible that the fox became infected by eating wild birds infected with avian influenza. The virus found in the fox is not related to the highly pathogenic zoonotic avian influenza (HPAI) H5N1 strains that have also infected humans in Asia.

Mammals with avian influenza

Infection of foxes with H5N1 virus was previously shown in two fox pups found in the Netherlands in May 2021. Several H5N1-infected foxes, seals and an otter have also been found elsewhere in Europe. The genetic analysis of the fox virus has also shown that it contains an important marker for virus infection of mammals. Similar genetic markers were also found in some viruses from infected mammals in other countries. However, more genetic changes are needed before an avian influenza virus can spread between humans.

Low risk for humans

The chance that people will become infected with avian influenza is very small; the National Institute for Public Health and the Environment (RIVM) still estimates the risk to public health as low. Nevertheless, it is important to be aware of foxes and other mammals with neurological symptoms that may be caused by avian influenza. Contact with sick and dead birds or other animals should also be avoided. Dead birds and other wild animals can be reported to the Netherlands Food and Consumer Product Safety Authority (NVWA) or Dutch Wildlife Health Centre (DWHC).