It has long been noted that COVID-19 patients can suffer from a wide range of neurological symptoms such as headaches, confusion and loss of taste and smell.
They are often the first symptoms of SARS-CoV-2 infection to arise and can be severe and long-lasting. They also occur indiscriminately in patients regardless of age or the presence of other medical conditions. But little is known about exactly how the disease affects the brain and central nervous system.
Now, a group of researchers at Tulane University in New Orleans, USA have published the first comprehensive study investigating the effects of the COVID-19 in the brains of non-human primates.
They found that subjects infected with SARS-CoV-2 showed signed of severe inflammation and injury indicating a reduction in blood or oxygen flow into the brain, neuron damage and small areas of bleeding.
Moreover, this type of damage was also seen in subjects that did not show signs of severe respiratory disease following infection from the virus, which may provide insight into the range of neurological symptoms associated with long COVID, the researchers say.
“Because the subjects didn’t experience significant respiratory symptoms, no one expected them to have the severity of disease that we found in the brain,” said lead author Tracy Fischer, PhD, lead investigator and associate professor of microbiology and immunology at the Tulane National Primate Research Center.
“But the findings were distinct and profound, and undeniably a result of the infection.”
The study was launched in the spring of 2020 and saw the researchers studying brain tissue samples taken from four rhesus macaques and four African green monkeys that had been infected with SARS-CoV-2, along with samples from two uninfected animals of each species that were used as controls.
The findings also mirror those of autopsy studies carried out in humans who have died of COVID-19 suggesting that rhesus macaques and African green monkeys can accurately act as a model for studying how humans experience the disease, the researchers say.
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