In recent years, coronaviruses of all stripes have received increased interest from scientists. After all, SARS-Cov-2, which caused a pandemic in 2020, is not the first member of this family to cause disease in humans. In 2003, there was an outbreak of the much more lethal SARS-1 in the world, which, fortunately, did not spread. And in 2012, MERS entered the arena with severe symptoms and high mortality, which was transmitted to people from camels.
A global catastrophe did not happen even then. However, a group of international researchers, having carefully studied MERS-CoV, came to a disappointing conclusion: it is only a couple of steps away from becoming another pandemic version of the coronavirus. A scientific article on this topic was published in the scientific journal Biological Sciences.
Recall that cases of MERS-CoV began to be detected in the world since September 2012. In the first two years, about 1.5 thousand infected people were registered in different countries; every third infected person died. Then, isolated cases of the disease were detected in the world: in total, from 2012 to 2022, 2601 cases of the disease were registered, with 935 deaths (36%). Most of these cases have been reported in Saudi Arabia. People have also been infected in Asia, a large outbreak, for example, happened in 2015 in South Korea. Then a resident of this country visited 4 countries of the Middle East at once and fell ill after returning to his homeland. Waiting in a crowded emergency room led to superspreading – 184 people were infected, 35 of them died. And although the incidence was recorded only in one Korean village, thousands of tourists then canceled their planned trips to South Korea, as well as Saudi Arabia, Qatar and the United Arab Emirates, where cases of MERS were recorded.
Camel flu, as this coronavirus was then called, began as an ordinary SARS (with fever, sore throat, sneezing and runny nose), but the further course was unpredictable. The latent period after infection can be 14 days. “The most common symptoms of MERS are: fever, sore throat, dry cough and shortness of breath. Symptoms of gastrointestinal upset are quite often observed: abdominal pain, nausea, diarrhea,” says laboratory diagnostics doctor Alexander Solovyov.
Mortality in coronovirus MERS reaches, according to various sources, from 10 to 50%. The disease is most often difficult to tolerate – they cause pneumonia, often kidney failure. Back then, it was believed that people with weakened immune systems, chronic lung disease, diabetes, and kidney failure were most at risk of contracting camel flu.
We were saved from a pandemic by the fact that the virus turned out to be low-contagious. With regard to transmission routes, the airborne route was not ruled out, however, the most likely way to get MERS-CoV was considered to be the consumption of raw camel milk or poorly cooked camel meat. “Studies conducted several years ago at Columbia University showed that the coronavirus is present in the body of 76% of camels in Saudi Arabia, and in some regions of the country almost all camels are infected with it. In fact, one could get sick only by visiting this country and having contact with camels. Therefore, back then, the virus was not widespread on the planet,” explains molecular biologist Konstantin Chernyakovsky.
However, 10 years have passed and the situation has changed. Just a few mutations – and the MERS-CoV virus will blow up the world with a new pandemic, in comparison with which the current one will seem like flowers, the authors of a new study say.
The MERS-CoV virus is now thought to be enzootic (i.e., geographically found) in camels in the Arabian Peninsula and the Middle East. It is curious that on the African continent, zoonotic (that is, capable of being transmitted from animal to person) MERS-CoV is not detected in camels, although there are a lot of dromedaries (one-humped camels) that are infected with MERS-CoV. More precisely, in Africa, 70% of dromedaries are infected with the camel flu virus, as in the Arabian Peninsula. But in Africa, camels do not infect humans.
Why the African version of the virus is not transmitted from camels to humans, while in Saudi Arabia the situation is fundamentally different is a mystery. “Geographically and genetically distinct viruses from Africa have a low ability to replicate in human and bat lungs, which provides a possible explanation for the absence of severe MERS disease in Africa. However, the findings suggest that MERS-CoV, now entrenched in the Arabian Peninsula, “has acquired increased human pathogenic potential. If pathogenic viruses from the Arabian Peninsula are brought to Africa, they are likely to become dominant, as they did in the Arabian Peninsula, and will be associated with adverse human health effects in Africa and an increased threat of a pandemic.” scientists note.
“The fears associated with MERS-CoV are not groundless,” continues Konstantin Chernyakovsky. “The fact is that many seasonal viruses were once common only among camels, and then, having mutated over several centuries, became zoonotic and endemic in the human population The first SARS came to us from bats and caused an outbreak in 2003. MERS-CoV, which can be transmitted to humans, is found only in camels in Saudi Arabia so far, but the virus mutates, and new work has shown that only a few mutations are left to change the situation. In our favor”.
Another concern of scientists is related to the assumption of a possible exchange of genetic information between MERS-CoV and pandemic SARS-CoV-2, which could lead to an increase in the epidemic potential of MERS-CoV. Scientists note that there is no better bioterrorist in the world than nature – and which way evolution will go, we can only wait.
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