Why Scientists Worried About Pandemic Respiratory Syndrome in the Middle East

Scientists are concerned about the transmission of another virus related to the coronavirus that has generated the pandemic since late 2019. It is the Middle East respiratory syndrome coronavirus, better known as MERS, and it may infect humans, bats and camels. It was first detected in 2012 and generated an epidemic that affected people in 21 countries until 2015. It was limited at the time, but MERS could be the cause of future outbreaks, according to the World Health Organization.

This month, the magazine PNAS of the US Academy of Sciences published a study that draws attention to MERS. The head of the work was the Sri Lankan-born virologist and pathologist Malik Peiris, a researcher at the University of Hong Kong, who was the first to describe the SARS coronavirus that caused the 2003 outbreak.

“The study that Peiris carried out with his team looked at variants of the MERS viruses in the Arabian Peninsula, Asia and Africa. Los resultados sirven para plantear la necesidad de hacer vigilancia y detección del MERS en las regiones donde occurs interacción entre el hombre y dromedarios, sobre todo en personas con síntomas de enfermedad tipo influenza o enfermedad respiratoria severa, como fiebre, tos y dificultad para respirar in Africa, where the presence of this virus is not sought, ”he commented to Infobae Dr Lucía Cavallaro, President of the Argentine Society of Virology.

In 2012, MERS first isolated the virus from a 60-year-old Saudi patient with acute pneumonia and severe kidney failure. From 2012 to July 2017, 2,040 cases were reported. It affected more men than women and had a death rate of around 30%, which is higher than that of COVID-19.

Peiris’ team focused on dromedaries, which are slightly smaller than camels. Until now, it was known that between 70% and 80% of camels had antibodies against the MERS virus. This meant that they had passed the disease or had it at the time of the analysis. In addition, It was known that up to 70% of infected animals do not live in the Arabian Peninsula, but in Africa. But what has drawn attention is that virtually no human case of MERS has been detected in Africa.

Scientists wanted to know why. They collected more than a dozen African variants of the virus, from Morocco to Egypt, via Nigeria or Kenya. They compared the data with that of the human variant that caused the outbreak in South Korea in 2015 and the dominant variant in Saudi Arabia.

They discovered that from a genetic standpoint, African MERS (technically called MERS-CoV) are grouped together separately and are distinct from current clade viruses circulating in the Middle East. But they share a similarity at the nucleotide level. By testing the different viruses in human lung cells and in genetically engineered mice, they found that the human and Arab variants easily infected and reproduced. However, African women were up to 100 times less capable of efficient replication.

The difference between the MERS variants of the two continents appears to lie in the S protein, which is the key with which coronaviruses enter cells. In most MERS in Africa, there are two changes in the amino acids of this protein which could explain its lower pathogenicity, although they do not exclude the existence of other variations of influence. They had the definitive proof of this thanks to the technique of reverse genetics: they modified the African coronaviruses so that they contain the protein of the Arab variants. In this way, observed that it increased its ability to squeeze into cultures of human bronchial cells.

“We show that the geographically and genetically distinct viruses from Africa have a low capacity for replication in the human lung, providing a possible explanation for the absence of severe MERS disease in Africa,” the scientists wrote. The results suggest that MERS, now located in the Arabian Peninsula, it has acquired a greater pathogenic potential for humans. We show that the “Spike” protein contributes to this phenotypic difference, they described.

The Peiris team left their alert: “If pathogenic viruses of clade B from the Arabian Peninsula are introduced to Africa, they are likely to become dominant, as they did in the Arabian Peninsula, and will be associated with adverse health effects in Africa and increased threat of pandemic. “.

Three months ago, the same researcher had already made another publication on a study with people working with camels. In this case, they were workers from a slaughterhouse in Kano, a town in Nigeria. None tested positive for MERS, but 30% had antibodies against the MERS-CoV virus. This study found that MERS has already reached humans in Africa, but not with the virulence of epidemics in Saudi Arabia or South Korea.

Among the potential solutions, Quim Segalés is a researcher at the Food Research and Technology Institute in Spain, working on the development of a vaccine against MERS-CoV for camels. Besides dromedaries and camels, alpacas, llamas or vicuñas are also susceptible to the virus. It only gives animals a cold. Since it does nothing to animals, there is no commercial interest in the private sector to develop an immunization that can be used to protect human health.

WHO has already included MERS “among the seven most dangerous emerging diseases”. It would take the Saudi variant to cross the Strait of Suez to become dominant among African dromedaries, and that would make human jumping easier and more serious. So far, a path has been drawn in the other direction. Saudi Arabia and the rest of the Gulf countries buy the camels sold by African countries. The risk is summed up by Peiris: “It has been able to protect us so far. But we have to make sure that this reverse trade is avoided, ”he told the newspaper. The country.

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