A study, carried out by American researchers from the University of Iowa, the Texas Biomedical Research Institute and Boston University (United States) and published in the journal Science Advances, depicts the journey of the Ebola virus from inside the body to the surface of the skin. Indeed, until now, it was thought that Ebola, mainly present in West, Central and East African countries, was transmitted through bodily fluids (saliva, semen, urine, etc.) of the sick or the dead. However, the 2013 to 2016 epidemic in West Africa revealed that the virus could also be found on the skin of the most infected people.
Scientists have therefore sought to understand how the virus can pass from inside the body of the sufferers to the surface of their epidermis (the superficial layers of their skin). Once it reaches the body of the sick, the infection can then be transmitted by simple skin contact.
Ebola, a deadly virus
Ebola is a virus that causes high fevers and hemorrhages. The disease is often fatal to humans. According to thePasteur Institute, its lethality rate is between 30 and 90% depending on the epidemics.
Read also Ebola: Portrait of a Killer Virus
It only takes three days for the virus to cross the skin
To understand how Ebola passes through the different layers of the skin, the scientists used a sample of human skin taken from healthy people. The researchers then introduced the virus underneath this sample, via the deeper dermal layers, to mimic the path of Ebola from inside the body to the epidermis.
Using this method, they were able to identify macrophages and endothelial cells, both useful to the immune system, fibroblasts, which structure the different layers of skin, and keratinocytes, the majority cells of the epidermis, as cells targeted by Ebola and through which the virus travels to the surface of the patients' bodies.
A human skin sample infected with the Ebola virus, in green (seen by confocal microscopy). In red, keratinocytes and in blue, the nuclei of cells of the dermis and epidermis. Credits: University of Iowa
This study also shows that the disease moves very quickly through the different layers of skin. Thus, in just three days, traces of Ebola were detectable on the epidermis of the samples.
Read also Ebola virus creates tunnels to infect cells undetected
Unique cells in the epidermis
Some of these identified cells, present in other organs of the body, were already known as vectors of the virus. However, keratinocytes, only present in the upper layers of the skin, are here identified for the first time as being able to absorb it, the researchers explain in a press release. This discovery allows a better understanding of the path of Ebola through the body and therefore to adapt the antivirals developed to fight the infection.
Finally, this use of human skin samples proves to be an inexpensive and very effective means for research, particularly in order to develop new treatments against the Ebola virus.
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