The Usutu virus originated in Africa and is named after the Usutu river in Swaziland. It can cause disease in birds and is transmitted by midges. The virus rarely causes disease in humans.
The first case of Usutu virus was reported in the Netherlands in 2016. Whenever a virus first enters a population the death count is high. It is not known how long it will take for the population to develop sufficient immunity to the virus which will result in fewer deaths. Furthermore, it is not yet clear as to how long the virus will persist in the Netherlands and, therefore, what the overall affect on bird poluations will be.
The virus originates from Southern Africa. The first outbreak in birds in Europe was seen in Italy in 1996 and was followed by an outbreak in Austria in 2001. The virus has subsequently been found in birds in Spain, Croatia, Hungary, Switzerland, Chechnya, Germany and Belgium. These countries reported mass die-offs of blackbirds. The virus was first seen in birds in the Netherlands in 2016.
Birds infected with Usutu virus may show one or more of the following signs:
General illness, apathy, puffed-up feathers, gasping for breath, stopping drinking, general weakness (i.e. not flying, flying low over short distances and resting frequently), drooping head and / or wings and loss of balance. The range of signs depends on which organs (e.g. heart, brain, peripheral nerves) are affected. These signs are not unique to Usutu virus and diagnosis must be based on further testing.
Usutu virus is an avian virus; in European countries where infected birds have been found, cats and dogs did not become sick, suggesting that the virus does not pose a risk to these animals.
The best way to protect birds is to minimize their exposure to infected mosquitos and midges.
There is no specific medicine for Usutu virus infection; care of infected birds consists of treating the symptoms.
The virus is transmitted by biting midges, particularly those belonging to the genus Culex. Human infection is rare but not impossible. Despite several large Usutu virus outbreaks in bird populations in Europe, only several people are reported to have become ill due to infection; the majority of these were immunosuppressed. Nonetheless, researchers have suggested that Usutu virus infection be considered in patients with meningitis or central nervous system symptoms1.
There are no specific measures for handling birds infected with Usutu virus. However, when handling sick or dead birds you should always follow the general hygiene guidelines outlined on the DWHC FAQ pages.