Bornavirus study in Maitenbeth: 157 mice examined - and good news

Created: 11/30/2022, 7:01 am

By: Katrin Woitsch

Two children from the small town of Maitenbeth died of the Borna virus, which has not yet been researched much.

A large-scale study should bring clarification.

The researchers presented their results on Tuesday.

Many questions are still open - but there is at least one piece of good news for the citizens.

Maitenbeth – The tree shrew is rare and harmless looking.

But she is a carrier of the highly dangerous Borna virus - that is one of the results of the study that the scientists presented yesterday in Mühldorf.

For the investigation, the Maitenbether had been asked to send dead shrews to the Friedrich Loeffler Institute (FLI).

A total of 157 shrews arrived at the researchers.

"16 of them were field shrews," reported FLI veterinarian Viola Haring.

"Of these 16, the Borna virus was detected in six." All other mice were virus-free.

The good news is that the animals are a relatively rare species.

Field shrews are not rodents, but are insectivores.

So far, they are the only known carriers of the virus.

336 ticks from the region were also examined – the virus was not found in them.

Large-scale search for the Borna virus in Maitenbeth

One piece of good news from the study is that infections with the Borna virus do not go undetected.

Three people were ill in the Mühldorf district, two of them were children from Maitenbeth.

In all three cases, the infection was fatal.

The researchers had asked the citizens of Maitenbeth for blood samples in July.

679 citizens took part in the study - that is 41 percent of the residents.

Antibodies against the virus were not detected in any of the blood samples, reported Merle Böhmer, infection epidemiologist at the State Office for Health and Food Safety.

There is no evidence of any other course of the infection.

And that means the condition is very rare.

Merle Böhmer, infection epidemiologist at the LGL

All nasal swabs were also negative.

This means that nobody in Maitenbeth was infected with the virus without realizing it.

"There is no indication of other forms of the infection," emphasized Böhmer.

"And that means the disease is very rare."

Taking blood for research: Maitenbether Mayor Thomas Stark was one of 679 residents of the community who took part in the study.

© Richterstetter

Borna infections in Maitenbeth probably a coincidence – location not a hotspot

One of the mysteries the researchers want to solve is why there were so many cases in the Mühldorf region.

Nationwide, only around 40 infections with the Borna virus are known.

To do this, the researchers analyzed the variants of the virus.

Two Bornavirus lines overlap around Mühldorf.

The two children from Maitenbeth were infected with different variants.

"There is no evidence that Maitenbeth is a hotspot from which further infections could emanate," explained Dennis Rubbenstroth from the FLI.

The children were probably infected in different places in the community.

It's more of a coincidence.

Most Borna infections are found in rural areas.

It looks harmless: the field shrew is considered a carrier of the Borna virus.

© Frank Rumpenhorst

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It is still unclear how the virus is transmitted to humans.

The soil samples taken by the scientists in Maitenbeth yielded no clues.

It is assumed that the field shrews transmit the virus via feces, urine or saliva.

20 percent of the study participants stated that they had had contact with shrews.

38 percent had seen shrews in the immediate vicinity.

It is unclear whether there are other carriers.

(By the way: Our Bayern newsletter informs you about all the important stories from Bavaria. Register here.)

The uncertainty in Maitenbeth is still there

The researchers presented the results to the Maitenbethern on Monday evening.

The interest was very high, reports Mayor Thomas Stark.

"The uncertainty is still there" - even if the virus is no longer a daily topic in town.

"The citizens are now above all relieved that no further cases have been detected." Mühldorf District Administrator Max Heimerl emphasized that the research work must not end now.

The interdisciplinary cooperation is to be continued, the money for this has already been promised.

The scientists want to continue taking targeted soil samples and examining field shrews.