Discovered in Salzburg

Virus causes meningitis in chamois

A tick-borne virus discovered in Salzburg causes brain inflammation in chamois (symbolic image).

(Bild: stock.adobe.com/makara stock.adobe.com )

A virus discovered in Salzburg affects chamois and causes severe encephalitis. It is unclear whether this could also be dangerous for humans. What is known so far about the "Alpine chamois encephalitis virus" and how great the danger really is.

In 2017, a hunter in a side valley of the Salzach (Salzburg) shot a chamois buck that was staggering and holding its head at an unnatural angle. The animal had an inflammation of the brain, reports Viennese virologist Norbert Nowotny in the journal "Viruses". Together with colleagues, he identified the genetic material of a previously unknown tick virus in the animal's brain. It is unclear whether this "Alpine chamois encephalitis virus" is also dangerous for humans, he told the APA.

After the animal shot in Salzburg, such pathogens were also found in the brains of two chamois in the Italian Alps. One of them was found dead in Piedmont in 2023, the other was found dying with movement disorders and muscle twitches in Lombardy. Both still had ticks attached, in which the previously unknown virus was detectable. It is obviously already widespread in the Alps, as the sites in Italy and Austria are up to 390 kilometers apart as the crow flies, according to the researchers.

"Alpine chamois encephalitis virus - ACEV"
The team led by Nowotny from the Center for Pathobiology at the University of Veterinary Medicine Vienna discovered that the virus belongs to the so-called flaviviruses. The researchers named it "Alpine chamois encephalitis virus - ACEV". "Until now, only one tick-borne flavivirus was known in Central Europe that can lead to neurological symptoms in humans and animals," says Nowotny: "Namely the European subtype of the TBE (tick-borne encephalitis, note) virus". This is notorious for causing meningitis in humans, but a vaccination protects against this.

Norbert Nowotny, virologist

(Bild: Jöchl Martin)

"The virus-positive ticks on the chamois were 'Ixodes ricinus' ticks, also known as 'common wood tick', which are the main carriers of the TBE virus," he explained. These common ticks could also potentially transmit ACEV to humans if they are bitten by an infected tick. "As chamois are closely related to goats, and somewhat more closely related to sheep, the possibility of infection via raw milk products from these animal species is probably higher," Nowotny said. We know from the TBE virus that there are many viruses in the raw milk of affected animals. However, they are completely destroyed during pasteurization.

Transmissibility to humans questionable
"We don't yet know whether humans are at all susceptible to this viral infection and show clinical symptoms," says Nowotny. The "host spectrum" and "zoonotic potential", i.e. the extent to which the disease can be transmitted from animals to humans, must therefore "definitely be investigated further", he says. 

"Since human TBE cases are almost never detected by PCR and subsequent sequencing, we do not know whether there have already been human infections with this new virus we have discovered," Nowotny explained: "But I can reassure you in this respect: It is more closely related to the Louping Ill virus, which is particularly widespread in the British Isles, than to the European subtype of the TBE virus, and the Louping Ill virus only very rarely causes disease in humans."