​Lesser known effects of Covid ● Mice are really annoying. Now they destroy fish too ● What did prehistoric people smell like, sir?

Less well known are the effects of Covid

Officially, at the end of last year, the UN reported more than 650 cases of infection with the COVID virus. Unofficially, the number is much higher, so you don’t even want to think about where the infection has reached.

The symptoms are already well known: headache, fever, cough, difficulty breathing, loss of smell and/or taste, etc., not to mention the so-called “long-term COVID” and its consequences. Well, scientists just discovered some you didn’t know were created by COVID.

For example, a 2021 study of 3,000 infected people found that about 80% of them had sleep disorders. The most common of them… insomnia. At the same time, another study, which included subjects from 14 countries, showed that infected people were much more likely to have nightmares. Obviously, from here you face other ailments and problems, but for now we will limit ourselves to the main ones.

The problem is that no one knows exactly why this is happening. The virus can affect the central nervous system or affect the blood supply to the brain. Anxiety, depression, stress and others were also taken into account. As I said, so far only the link between Covid and the mentioned problems has been found. It will be a while before we know the whole story.

Mice are really annoying. Now they are also destroying fish

It’s not like the mice went diving or fishing. But they still wreak havoc, even indirectly. Scientists are just beginning to understand the relationship between cause and effect. Please, it would seem that it is quite simple to draw a conclusion, but this is how science works, you need research, evidence, confirmation.

These studies were recently conducted on several islands in the Indian Ocean, and the results were published in the journal Nature Ecology and Evolution. In particular, the situation on five islands infested with mice and five islands infested with mice was analyzed. It turned out that the fish population around the mouse islands fell sharply. Well, now we have an answer to this situation as well.

It appears that the mice that arrived there by ship around 1700 found ideal prey in the native birds and their nests. As a result, in some areas the density of birds decreased by as much as 720 times. Huge! Fewer birds, less waste they leave behind. Less trash enters the water, less nutrients for marine vegetation. Less vegetation, goodbye fish. It was. Like I said, they are really annoying.

What did prehistoric people smell like, sir?

Not how they smell, but how they perceive the smells around them. This is exactly what the study of the iScience magazine is about, so as not to create confusion among readers. Well, as difficult as it may seem to figure out, or even impossible from the point of view of some, it seems that we have some pretty clear clues.

This happened thanks to the efforts of a Franco-Japanese group of geneticists, who removed the genes responsible for smell from the genomes of modern humans, as well as from the genomes of extinct species, such as Neanderthals and Denisovans.

Comparing them, they were able to find out that Denisovans, for example, were somewhat less sensitive to floral smells, but they perceived the smell of sulfur four times better, and balsamic three times stronger. It seems they had an olfactory sensor that responded very well to the smell of honey.

In contrast, in the case of Neanderthals, the sense of smell seems to have been relatively the same as that of modern humans. They still had some small changes, we couldn’t be identical, but one difference to note is that they were less sensitive to the smell of urine and sweat. Which was very good in those harsh times, when there were no showers, and precipitation usually came in the form of sleet.

Overall, the study authors say they also have a general conclusion. In particular, the sense of smell evolved in the human species, with certain receptors being allocated on a case-by-case basis precisely so that these individuals could smell the odors of potential food sources. And it worked when you didn’t have too many different sources.

In our case, in the modern case, these sensations have started to fade, in the sense that we have multiple sources of food, we no longer need to feel them hundreds of meters from a store, so the evolutionary pressures are not really there anymore. That’s all. No luck! Basically, that’s how evolution works.

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