New studies dispute the assertion that the rats were the ones who transmitted the Black Death, but in any case it turns out that they could be a storehouse of viruses from the corona family
For many years, researchers blamed the rats for the outbreak of the Black Death. They believed that the rats were responsible for the death of about 25 million people between the years 1347-1351, but recent studies show that the epidemic spread very quickly which is not possible thanks to the rats, and that it is possible that other and more likely pests are involved. Today, it is widely accepted that parasites such as fleas and body lice are the main causes of the spread of the Black Death and, in fact, of a series of spreads of the same bacteria that caused it - Yersinia pestis - until the 19th century.
But to say that the rats are innocent would be a kind of deviation from the truth; After all, these mammals are still vulnerable to pathogens that also harm us, such as the bacterium Yersinia pestis. Pests such as fleas may suck blood from a sick rat, and once the rat dies, the fleas leave the carcass and may transmit bacteria and viruses to humans by biting. In fact, it is known that epidemics that spread after the 19th century - including the epidemic that occurred in Madagascar in 2017 - were "helped" by rats and other rodents in such a way.
Why are rats apparently not responsible for the Black Death?
Since rats do play a significant role in modern plagues, and in light of the fact that genetic evidence indicates that victims of the Black Death from the Middle Ages died from the bacterium Yersinia pestis, it was clear to the researchers that rats were the main source of the spread of the Black Death. But many historians believe that there are two reasons that make this idea improbable:
1. The Black Death spread in Europe at a much faster rate than any modern plague.
2. In modern plagues you can see evidence of death in large quantities of rats before the spread of the disease in humans, but there is no documentation from the Middle Ages that shows such a phenomenon.
For this reason, researchers have toyed with the idea that parasites such as fleas and body lice are responsible for the spread of the Black Death, regardless of rats, since once they reach one person, it is very easy for them to jump on another person and transmit the disease.
Mathematically, the pattern in which diseases spread among a population is different in each of the cases that can cause it: rats get sick with fleas or parasites in humans. According to models created by researchers for the patterns of disease spread in 9 different cities in Europe during the Middle Ages, it was found that 7 of them were more suited to the pattern of a disease that spreads due to parasites in humans. In fact, it appears that even if there were operations throughout Europe Rat extermination inclusive, the Black Death was still spreading throughout her.
Can rats be responsible for the spread of the corona virus?
Make no mistake - although the rats were probably not the ones that spread the Black Death across Europe, they could still be an influential factor in the spread of other plagues. In a study published on November 17, 2021 in PLOS Computational Biology By Sean King and Mona Singh of Princeton University, it was found that rats that had been infected with SARS and similar viruses for many generations - such as Corona - developed resistance or resistance to these pathogens.
SARS-CoV-2, the virus that causes infection with COVID-19, has a zoonotic origin, meaning it is transmitted from a non-human being to humans. Previous studies show that Chinese psittacine bats are carriers of several SARS-like viruses, but they do not suffer from severe symptoms. That is why it is so important that researchers also identify other animals that have developed mechanisms that made them resistant to Corona, this is so that we can increase awareness regarding the viral potential of the disease to spread to humans.
In the current study, King and Synge conducted an evolutionary analysis among different species of mammals and tested the ACE2 receptors, through which SARS viruses enter cells. In primates (frozens), essentially identical amino acid chains were found in the regions where the SARS viruses usually bind to ACE2. In rats, on the other hand, there was more diversity and even an accelerated evolutionary process in these areas.
The results suggest that viral infections such as SARS have not greatly affected the evolution of primates throughout history, but certain rat species have been repeatedly exposed to SARS-like viruses over long evolutionary periods and have been affected by it. The authors of the study say that the rats actually developed a type of resistance or resistance to these viruses as a result of the infections they suffered in their evolutionary history, and this raises the suspicion that modern rats may be asymptomatic carriers of corona-like viruses and even viruses for diseases that have not yet been discovered.
So should we start fearing rats?
Despite the findings, this does not mean that you should fear rats too much - at least not when it comes to Corona. Yes, it is recommended to hire a professional mouse catcher to help you get rid of a rodent that has appeared in your home, but that rodent will most likely not infect you with COVID19. There are many different types of SARS-like viruses, and COVID19 is just one of them, and for now it has been found that the danger of it passing from rats to humans is very low, and even if it is possible, it is only under extremely extreme conditions.
Nevertheless, and as mentioned earlier, rats can certainly be carriers of diseases that have not yet been discovered, and throughout history they have indeed been a factor that helps the spread of diseases and epidemics - even if not directly. So how can the danger be reduced? The answer is to exterminate mice and rats if necessary - when they invade your private space. Of course, this is not what will stop an entire epidemic, but the rats always put you at risk of exposure to various bacteria and viruses, among other things due to the feces they leave in the areas where they find their food, i.e. in your kitchen. The recommendation is to simply remove any unwanted rodent from the house - even before it starts doing damage that will harm your health, among other things.
The article is promoted content for site surfers, courtesy The catcher - a professional mouse catcher.
