A team of virologists from Germany, France, Belgium and the United States, based on a study of a museum preparation a century ago, found that measles has been accompanying humanity for more than 2500 years.
The study was based on the almost completely reconstructed genome of the measles virus, extracted from the lung tissue of a girl who died of the disease in 1912. The drug was kept in the medical history museum of the Berlin clinic "Charite".
According to scientists, the genome sequenced by them has become the oldest in the world - and not only for the measles virus, but in general for RNA viruses infecting humans. “We were delighted that our experiment was a success the first time, and that we were able to obtain viral RNA from such an old sample,” says Sebastien Calvinjak-Spencer of the German Robert Koch Institute.
The resulting genome was compared by virologists with later and modern samples of the measles virus, as well as the related rinderpest virus. In doing so, they used the molecular clock method, which allows, based on mutations, to determine the time of divergence of taxa, and, accordingly, their age.
The calculations showed that the measles virus appeared around the sixth century BC, that is, almost one and a half millennia earlier than previously thought. Previous ideas that measles originated in the Middle Ages were also based on the method of molecular clocks, but, as the authors of the study note, when conducting those previous calculations, it was not possible to study the evolutionary dynamics of the virus over a long period of time - there were no such old samples as they managed to get now.
As with many viruses, measles appears to have been transmitted to humans from animals, and it is likely that this pathogen and rinderpest virus share the same ancestor. At the same time, scientists suggest that the appearance of the disease was also associated with social factors - the measles virus requires a fairly high population density to spread, and such conditions just arose around the sixth century BC along with the growth of population and the development of large cities in Europe and Asia. The authors of the study consider this version to be at least reasonable.