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The Usutu virus has recently been detected for the first time in the Netherlands. The virus has been detected in captive great grey owls (Strix nebulosa) as well as in wild, dead and living, common blackbirds (Turdus merula). Various research organisations have reported this including the Dutch Wildlife Health Centre and Erasmus MC. The Usutu virus is an avian virus that has been present in Europe for a considerable time.

Since August more than 40 reports have been received by the Dutch Wildlife Health Centre about mortality among common blackbirds in the Netherlands. This increased mortality has mainly been observed in several areas in the provinces of North Brabant, Gelderland and Limburg. Captive great grey owls have also died and several of these birds have been investigated at the Veterinary Pathology Diagnostic Centre of the Faculty of Veterinary Medicine (Utrecht ľ¹Ï¸£ÀûÓ°ÊÓ). Samples from both the common blackbirds and the great grey owls were sent to Erasmus MC for research into the Usutu virus. It is known that this virus can cause increased mortality among these birds. Furthermore, the Usutu virus was recently also detected in the German state of North Rhine-Westphalia close to the Dutch border. An increased mortality among common blackbirds has also been reported in Belgium.

Usutu in living blackbirds

This virus has also been found in two living common blackbirds. These common blackbirds were captured for sampling as part of the study of Erasmus MC and the Dutch Centre for Avian Migration & Demography of the Netherlands Institute of Ecology in which the prevalence of zoonotic viruses in wild birds in the Netherlands is being investigated.

Five organisations (Dutch Wildlife Health Centre, Erasmus MC, Sovon, Dutch Centre for Avian Migration & Demography and Veterinary Pathology Diagnostic Centre) are working closely together so that unusual mortality and the presence of diseases in birds can be rapidly mapped. Reporting ill and dead wild birds to or the is important for being able to accurately follow the spread of this virus. Bird ringers affiliated with the Dutch Centre for Avian Migration & Demography will take extra samples from captured blackbirds in the coming weeks so that the spread of the Usutu virus can be established.

Background

The Usutu virus is a so-called arbovirus that occurs in birds. In recent decades this virus has been repeatedly detected in birds in Europe, especially in Spain, Italy, Croatia, Hungary, Austria, Switzerland, Czech Republic and Germany.

The Usutu virus causes mortality among songbirds and owls, with extensive mortality among common blackbirds, house sparrows (Passer domesticus) and great grey owls in particular. The virus might also be prevalent in other songbirds and owls.

People

It is very rare for people to become infected with this virus. The virus is transmitted by mosquitoes, especially from the genus Culex. Up until now there have been just five known cases of patients infected with the Usutu virus despite large-scale outbreaks among birds. In three of these patients the immune system was compromised.

The measures for dealing with living or dead infected birds have not changed. The standard hygienic measures apply (see ).