In addition to causing serious neurological damage to the fetus, Zika virus can also infect the adult brain, continue to reproduce there and affect the central nervous system, according to a study by Brazilian researchers, published in Nature Communications.
Although in the beginning it was considered that in adults the Zika virus caused only a febrile state, muscle pain and skin rashes, the infection was recently related to the development, in some cases, of neurological complications that include acute myelitis, encephalitis and meningoencephalitis.
In adults, some studies had detected the presence of the virus in the fluid that bathes the brain and spinal cord and in the lymph nodes, but it remained to be determined whether mature neural cells and adult human brain tissue were susceptible to Zika infection.
“Based on previous work demonstrating that the virus preferentially infected immature neurons [as in the developing brain of fetuses], we sought to investigate whether the virus infected adult neural cells and how it would do it,” said neuroscientist Claudia Pinto Figueiredo, coordinator of the Postgraduate Program in Pharmaceutical Sciences of the Federal University of Rio de Janeiro (UFRJ) and one of the coordinators of the study.
Scientists first discovered that the virus, incubated in fragments of brain tissue from uninfected adult patients, not only caused infection but continued to replicate and produce new viral particles capable of infecting other cells.
Then, to assess the consequences of the infection, the researchers inoculated the virus isolated from an infected patient in the brain of adult mice and observed that Zika produced new viruses and multiplied especially in areas of the brain related to motor control and memory.
“Our results indicate that neurons are the main cell type infected by Zika in the adult mouse and the human brain. The current findings contrast with those reported in the developing brain, when Zika infects both neurons and glia, suggesting that the virus can target different cell populations at different stages of brain development,” the authors explained.
“Few studies have addressed whether the virus can affect mature cells, hence the contribution of the study, which responded that the virus is not only capable of infecting but can replicate and damage mature neurons,” said Fernando Bozza, a researcher at the National Institute of Infectious Diseases of the Oswaldo Cruz Foundation, which was not involved in the research. However, Bozza stressed that the study was conducted in mice as an experimental model and notes that adult humans with Zika rarely develop complications of the central nervous system.
Source: Agencia ID