Rare Borna virus infection in Bavaria: what you need to know about the pathogen

In Bavaria, infection with a virus is very rare Borna virus been proven. As the county office announced on Tuesday, a person from the Mühldorf am Inn district was infected. There is no other information yet. The disease, which is usually fatal, occurs only in a few isolated cases in humans in Germany.

From two to six diseases infected with Borna virus annually in Germany

Two other cases of Borna virus infection have spread to the region during the past three years. The so-called classic Borna virus causes inflammation of the brain that ends fatal in almost all cases. Those who survive usually retain severe collateral damage. On average, two infections are reported in Germany each year. However, scientists assume that the number of unreported cases is higher – up to six per year, which is still very rare.

But what is the cause of this lethal factor? How is it transmitted? Overview.

What is Borna virus?

Borna virus is also known as Borna Disease 1 (BoDV-1), “classic Borna” and “Pferdeborna” and has been an animal disease for more than 250 years. In 2018, BoDV-1 was first identified as the cause of acute encephalitis in humans.

To date, the pathogen has not been adequately investigated. In order to learn more about Bornavirus in humans, two research groups on the pathogen, Bornavirus Focal Point Bayern and ZooBoCo, have been established over the past five years. Among other things, they investigate transmission routes, risk factors, virus vectors, and other possible forms of infection.

BoDV-1 is clearly distinguishable from the so-called spotted squirrel bornovirus. The virus can also be transmitted to humans and can cause severe meningitis.

How is the pathogen transmitted?

The shrew is the only known reservoir of the virus to date. The pathogen of infected animals is usually excreted in saliva, urine or feces. Scientists currently hypothesize that horses and sheep come into contact with shrews and their excrement when eating, for example.

The mouse does not have to be touched. Bornaviruses can, for example, be ingested through food or water contaminated with feces and transmitted to humans. In addition, bite injuries and inhalation of contaminated dust can transmit the pathogen to humans. It is conceivable that other animals such as pet cats that hunt mice are a link in the chain of transmission, according to a Robert Koch Institute (RKI) report. It is currently being investigated whether other closely related shrew species such as garden shrews can transmit the virus.

So far, scientists consider person-to-person transmission unlikely.

In what areas can it be found?

The field shrew where the pathogen host is found is mainly found in Central and Southeast Europe. In Germany also, it increasingly occurs in the eastern half of Germany, especially in Bavaria, Thuringia and Saxony-Anhalt. In addition, the virus has been detected in animals in Switzerland, Liechtenstein and Austria.

What are the typical symptoms?

According to the RKI, the following symptoms are known so far:

  • Initial stage: headache, fever, general malaise
  • Other course: Neurological symptoms, eg behavioral problems, speech and gait disturbances
  • Advanced stage: coma

So far, all but one of the known cases have been fatal. There is currently no specific treatment against infection with pathogens.

How likely is infection?

Currently, only a few cases of the disease in humans are known. According to the Bavarian State Office for Health and Food Safety, the number of infections has been in a double-digit average range since 1996. In 2021, seven infections spread across Germany, five of which were in Bavaria. Individual cases have also been reported in Brandenburg, Saxony-Anhalt, Thuringia and North Rhine-Westphalia.

Where March 1, 2020 There is a requirement to report a bornavirus infection. Accordingly, direct detection of Bornaviruses in humans should be reported to the Department of Health for Laboratories.

How can you protect yourself?

At the moment, Borna virus infections are very rare. The risk of infection is correspondingly low. To date, for example, there is no available vaccination against the pathogen.

In order to protect yourself however, RKI summarized the following precautionary measures:

  • Avoid contact with the shrew.
  • Shrews are not suitable as pets.
  • Live or dead shrews should not be touched with their hands.

What should you do if you find a tiger in your home or work environment?

  • If shrews are identified in the home or work environment, it is important to identify their food source and remove it from them. Outside, this can be dog and cat food, piles of manure or other droppings.
  • If the animal is already dead, you should remove the carcass and carefully clean the contaminated surfaces with household cleaners. Spray dead shrews and droppings well with a commercial cleaning agent first to prevent virus-laden dust from forming. Wear rubber gloves when removing the carcass and wear a tight-fitting mouth mask when dust forms.
  • To remove the carcass, place it in a plastic bag placed over your hand, seal it and dispose of it in household waste.
  • In dusty areas, take a shower immediately and wash used work clothes.

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