The novel coronavirus may perhaps enter the brain of people today by way of the nose, according to a study published on Monday that may perhaps aid clarify some of the neurological symptoms observed in COVID-19 individuals, and inform diagnosis and measures to avert infection.
The investigation, published in the journal Nature Neuroscience, noted that SARS-CoV-2 not only impacts the respiratory tract but also impacts the central nervous program (CNS), resulting in neurological symptoms such as loss of smell, taste, headache, fatigue and nausea.
Although current investigation has described the presence of viral RNA in the brain and cerebrospinal fluid, it remains unclear exactly where the virus enters and how it is distributed inside the brain.
The researchers from Charite Universitatsmedizin Berlin, Germany examined the nasopharnyx — the upper element of the throat that connects to the nasal cavity — a most likely initial internet site of viral infection and replication, and the brains of 33 individuals — 22 males and 11 females — who died with COVID-19.
The median age at the time of death was 71.6 years, and the time from onset of COVID-19 symptoms to death was a median of 31 days, they stated.
The researchers stated that they located the presence of SARS-CoV-2 RNA, the genetic material of the virus, and protein in the brain and nasopharynx, adding intact virus particles have been also detected in the nasopharynx.
The highest levels of viral RNA have been located in the olfactory mucous membrane, they stated.
According to the researchers, the illness duration was inversely correlated with the quantity of detectable virus, indicating that greater SARS-CoV-2 RNA levels have been located in instances with shorter illness duration.
The group also located SARS-CoV-2 spike protein in particular kinds of cells inside the olfactory mucous layer, exactly where it may perhaps exploit the proximity of endothelial and nervous tissue to get entry to the brain.
In some individuals, SARS-CoV-2 spike protein was located in cells expressing markers of neurons, suggesting that olfactory sensory neurons may perhaps be infected, as properly as in the brain locations that get smell and taste signals, the researchers stated.
SARS-CoV-2 was also located in other locations of the nervous program, like the medulla oblongata — the major respiratory and cardiovascular handle centre of the brain, they stated.
The researchers noted that additional COVID-19 autopsy research that consist of a broad variety of sampling are necessary to recognize the precise mechanisms that mediate the virus’s entry into the brain, and examine other prospective ports of entry.