Scientific News

Borna virus transmitted by shrews – fatal cases identified in Germany

A team of German researchers identified eight cases of Borna virus (Bornaviridae family), a virus transmitted by shrews, in eight patients hospitalized between 1999 and 2019 for encephalitis. As reported in the study in The Lancet Infectious Diseases, these cases were all recorded in southern Germany. In particular, cases would have spread mainly among people in rural areas.

The virus is transmitted by the shrew (family of soricides), a rat-like mammal that is spread a little bit around the globe. It is considered one of the smallest mammals in existence. According to the researchers, these animals transmitted the virus to domestic cats, which in turn transmitted it to their owners or humans.

Symptoms of the infection include headaches, confusion, fever, convulsions and memory loss as well as, in the most serious cases, loss of consciousness. All eight patients examined by the researchers died between 16 and 57 days after admission.

This is precisely why the researchers believe that Borna virus infection should be considered a serious and potentially lethal disease for humans, as Barbara Schmidt of the University of Regensburg reports. Moreover, it is not known why, it seems to have gone completely unnoticed as far as infections in humans are concerned.

Although rare, this virus could still be the cause of unexplained cases of serious encephalitis, as Martin Beer of the Friedrich-Loeffler Institute, another author of the study, points out.

Scientific News

Expansion of the universe: what if we were in a giant bubble of different density?

A new study of the speed at which the universe is expanding seems to resolve, at least in part, the divergences that physicists and cosmologists have achieved by trying to measure it. The new study, published in Physics Letters B, does so without resorting to any “new physics”.

Currently there are two methods used to measure this speed: the first is based on the cosmic microwave background and the data provided in particular by the Planck space mission. According to this first method we obtain a value for the so-called “Hubble constant” of 67.4 (km/s)/Mpc. That is, the universe is expanding 67.4 km/s faster every 3.26 million light years.

The second method is based on supernovae that appear sporadically in distant galaxies. Measuring these strong light events gives a Hubble constant value of 74.
Lucas Lombriser, researcher at UNIGE’s Faculty of Science, says: “These two values have continued to become more precise for many years while remaining different from each other. It didn’t take much to trigger a scientific controversy and even raise the exciting hope that perhaps we were facing a ‘new physics'”.

According to Lombriser, perhaps these differences are due to the fact that in the end the universe is not as homogeneous as it has always been claimed. It has always been difficult to imagine, for example, fluctuations in the average density of matter calculated on volumes thousands of times larger than a galaxy.

This is precisely why Lombriser, in his new study, theorized the existence of a gigantic bubble, 250 million light years in diameter, in which our galaxy is also present and in which the density of matter is significantly lower than the density known for the entire universe.

Such a thing would have an impact on the calculation of Hubble’s constant because this same bubble would include the galaxies that are usually referred to when measuring distances.

So, by establishing that this huge bubble exists and establishing that the density of matter inside it can be 50% lower than that of the rest of the universe, we would obtain a value for the Hubble constant that would converge with the one obtained using the first method, that of the cosmic microwave background: “The probability that there is such a fluctuation on this scale ranges from 1 in 20 to 1 in 5, which means that this is not the imagination of a theorist. There are many regions like ours in the vast universe”.