Recent epidemics seem linked to contamination from one person to another, particularly during sexual intercourse.
The different mpox epidemics in Africa respond to different logics, shows a study published Thursday October 24, finding that the new variant of the virus is transmitted mainly between humans while contamination by animals remains the majority for the older version. “Human cases of mpox in the Democratic Republic of Congo (DRC) are driven by two transmission patterns”summarizes this study, published in the journal Cell.
Several epidemics of mpox, also known as “monkey pox”, are underway in the DRC and, to a lesser extent, in neighboring countries. They are fueled by two different versions of the virus, clade 1 which has been circulating for decades, and clade 1b, a new variant. The latter was notably identified in a patient in Germany, one of the very rare cases where this version has been spotted outside the African continent.
A global epidemic of mpox, a disease which results in multiple skin lesions, has also continued since 2022 but involves an even different version of the virus, called clade 2. This complex situation, which has led the World Health Organization (WHO) to declare mpox as a global emergency, pushes researchers to question the specificities of these different versions, whether in terms of dangerousness, contagiousness or modes of transmission.
Two logics are at work
It is on this last point that the Cell study focused. Historically, mpox is in fact best known for being transmitted through contact with animals, particularly through the consumption of contaminated flesh. But recent epidemics also seem linked to contamination from one human to another, in particular during sexual intercourse.
The study, which is based on the genetic analysis of viruses taken from several hundred patients, concludes that both logics are at work. The cases linked to version 1a seem mainly to come from contamination by different animals, while variant 1b much more often presents a mutation typical of its adaptation to humans. This therefore suggests that it is first transmitted from one human to another.
