The fetal brain is not the only one affected by Zika. Research on mice has shown the effect the virus can have on adults.
Studies on the Zika virus are multiplying and so are fears. Already known to attack the brain of fetuses (risk of microcephaly), this virus would not be without consequences on that of adults. In any case, this is shown by a study published a few days ago in the journal Cell Stem Cell.
Conducted on mice at La Jolla Institute for Allergy & Immunology (California), this work reveals that adult cells involved in learning and memory can be destroyed by this virus. “It is proven that Zika can penetrate the adult brain and wreak havoc,” says Prof Sujan Shresta, one of the co-authors of the research.
Effects that are difficult to predict
This team focused on cells destined to become neurons. These have been shown to be particularly susceptible to the virus but only in two parts of the brain, including the hippocampus.
To reassure, these scientists specify all the same that “apart from the fact that the models established on mice are not necessarily transposable to humans, the long-term effects on the adult brain are difficult to predict. “They are undoubtedly more subtle, but now we know what to expect”, writes Professor Shresta.
The suspicions are confirmed
And this is also what Professor Daniel Camus of the Institut Pasteur de Lille thinks. Head of a working group on Zika at the High Council for Public Health (HCSP), he confided to Why actor that “it was suspected from the start that the Zika virus causes neurological disorders. That this happens in adults is no wonder. There is a neurotropism of this virus for nervous tissue. Clinically, it is a logical deduction ”.
The latter explains, however, that more detailed studies will be needed to confirm it “because neurological disorders at the start of development are often major and therefore easily detectable. It is the opposite in adults where there are few evolutionary phenomena, ”he emphasizes.
Fears about Guillain-Barré syndrome
For his part, Professor Shresta indicates that the sensitivity of this type of cell to the virus could explain the appearance of Guillain-Barré syndrome (GBS) in certain patients infected with Zika, once the virus has disappeared. GBS strikes the peripheral nervous system and manifests itself in general weakening or even progressive paralysis.
There again, nothing surprising for Professor Camus “still because of the very clear neurotropism of this virus”. However, he indicates that as SGF is also involved in an inflammatory phenomenon, “we must be very careful before alerting on this subject”.
In the end, the infectious disease specialist therefore wants to be reassuring: “there are many other diseases for which there are cerebral lesions, but they are often minimal and clinically not very visible”. “We just have to stay vigilant. It is a disease that we discover every day, ”he concludes.
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