Large blackbird death by exotic Usutu virus in several German cities

Usutu virus is killing more and more blackbirds in Germany

The exotic Usutu virus, which was first detected in this country in 2011, provides again and again for regional bird deaths. Now Hamburg is affected for the first time. Blackbirds fall victim to the pathogen. People can also become infected - but that only happens in very rare cases.

Hamburg will be affected for the first time this year

In 2011, the tropical Usutu virus, which is transmitted by mosquitoes to birds, especially in late summer, was first recorded in Germany. In the following years, the pathogen repeatedly caused regional bird deaths. This year Hamburg is affected for the first time. The Bernhard Nocht Institute for Tropical Medicine (BNITM) and the Nature Conservation Union (NABU) ask the population to report sick or dead animals under "www.nabu.de/usutu-melden" and if possible submit them for examination.

The death of birds by the tropical Usutu virus continues this year and now also affects Hamburg for the first time. Especially blackbirds are affected. (Image: Bernd Wolter / fotolia.com)

Warm summer has favored spread of the exotic virus

"We have already received 55 telephone reports of Usutu suspected cases in Hamburg since the beginning of August," explained Marco Sommerfeld, bird protection officer at the NABU Hamburg in a joint press release.

"I assume that the warm summer has favored the spread of the original exotic virus."

According to the experts, since 2011 the Usutu virus is increasingly spreading through Germany.

Whereas in the first years only heat-favored regions along the Rhine Valley and the Lower Main were affected, since the year 2016 a spread over North Rhine-Westphalia to the north as well as a separate outbreak in the area Leipzig and Berlin could be determined.

For the first time, the regions around Nuremberg and between Bremen and Hamburg seem to be affected for the first time this year.

Significantly more reported cases

"The cases reported so far in 2018 clearly exceed the figures from previous years, which speaks for a particularly strong appearance and for a spread of the virus," said Lars Lachmann, bird expert from the NABU Federal Association.

Since 2011, ornithologists and tropical medicine specialists have been able to find that many birds die when the virus first appears in a region such as Hamburg. In the following years, the number of deaths then usually sink to a lower level.

In order to document the actual spread of the virus, it was important to be able to confirm as many suspected cases in the laboratory. Appropriate investigations are carried out by the BNITM and some veterinary examination offices.

According to the information, over 200 dead birds from all over Germany have been sent to BNITM this year, of which 132 have been examined so far. In 33 percent of the animals already examined, the BNITM has detected the Usutu virus.

"The highest activity is to be observed in Hamburg this year", Dr. Renke Lühken from the Bernhard Nocht Institute for Tropical Medicine. "Here we were able to detect the virus in 12 birds sent in."

Pathogens can cause mass bird dying

As explained by the Friedrich-Loeffler-Institute (FLI) (Federal Research Institute for Animal Health) on its website, the Usutu virus, which originated in Africa, was first diagnosed in Europe at the beginning of the millennium.

The main hosts for the pathogen are wild birds, which usually do not fall ill. However, also very sensitive bird species are known, for example black birds, which are very easily infected.

Infected birds often show apathy and central nervous system disorders such as tumbling or twisting the head. It can come to mass bird death.

According to the experts, infections occur mainly during the mosquito season from May to September.

According to BNITM, infected birds cease to flee and usually die within a few days. Almost always it is blackbirds that are diagnosed with this disease, which is why the Usutu epidemic also became known as "blackbird dying".

However, other species of birds are also affected by the pathogen and can die from it.

Infection can not be treated

"Unfortunately, you can neither prevent nor treat Usutu infections," Lachmann explained.

"All that remains is to take the unique opportunity to document the effects of a bird disease new to Germany on wild birds and to estimate their consequences," says the bird expert.

"The aim is to be able to compare and assess novel sources of danger for bird species with other threats such as climate change and habitat loss."

Dead birds should only be used with protective gloves or a plastic bag that has been turned upside down.

There is also a risk of infection for humans.

"Humans can be infected by the Usutu virus, but - as with most mosquito-borne viruses - it's very rare to have serious illnesses," Dr. Renke Lühken. (Ad)