These isolated cases of infection were contained immediately as they were recognized prior to mutation into full Influenza H1. 2, there have been 3 documented infections of Zombie Flu, worldwide. 2 to release this information without being in violation of our confidentiality agreement. “It’s quite possible that you’ll see a combination of both.It is imperative that this information be freely available to the public for safety reasons and we are authorized under EE: 2. Zandi said.īut in some people, he added, it may be low blood oxygen from infected brain cells that leads to strokes: “Different groups of patients may be affected in different ways,” he said. “There’s no need for the brain cells themselves to be infected for that to occur,” Dr. They may be the result of pervasive inflammation throughout the body.įor example, inflammation in the lungs can release molecules that make the blood sticky and clog up blood vessels, leading to strokes. But the symptoms may not all stem from the virus’s invasion of brain cells. Robert Stevens, a neurologist at Johns Hopkins University. Researchers will need to analyze many autopsy samples to estimate how common brain infection is and whether it is present in people with milder disease or in so-called long-haulers, many of whom have a host of neurological symptoms.įorty percent to 60 percent of hospitalized Covid-19 patients experience neurological and psychiatric symptoms, said Dr. “I think this is a case where the scientific data is ahead of the clinical evidence,” Dr. It’s unclear which route the pathogen is taking, and whether it does so often enough to explain the symptoms seen in people. The virus may get to the brain through the olfactory bulb - which regulates smell - through the eyes or even from the bloodstream. The lung-infected mice did neither.ĭespite the caveats attached to mouse studies, the results still suggest that virus infection in the brain may be more lethal than respiratory infection, Dr. When researchers introduced the virus into these mice, the brain-infected mice rapidly lost weight and died within six days. Her team then looked at two sets of mice - one with the ACE2 receptor expressed only in the brain, and the other with the receptor only in the lungs. “It’s pretty clear that it is expressed in the neurons and it’s required for entry,” Dr. Iwasaki and her colleagues looked more closely and found that the virus could indeed enter brain cells using this doorway. Previous studies have suggested, based on a proxy for protein levels, that the brain has very little ACE2 and is likely to be spared. That protein appears throughout the body and especially in the lungs, explaining why they are favored targets of the virus. The virus infects a cell via a protein on its surface called ACE2. “We don’t know yet if that is reversible or not.” “Days after infection, and we already see a dramatic reduction in the amount of synapses,” Dr. The coronavirus seems to rapidly decrease the number of synapses, the connections between neurons. These findings are consistent with other observations in organoids infected with the coronavirus, said Alysson Muotri, a neuroscientist at the University of California, San Diego, who has also studied the Zika virus. “This virus has a lot of evasion mechanisms.” The researchers didn’t find any evidence of an immune response to remedy this problem. Instead, it chokes off oxygen to adjacent cells, causing them to wither and die. The coronavirus is much stealthier: It exploits the brain cells’ machinery to multiply, but doesn’t destroy them. Immune cells then flood the damaged sites, trying to cleanse the brain by destroying infected cells. Other pathogens - including the Zika virus - are known to infect brain cells. Iwasaki and her colleagues documented brain infection in three ways: in brain tissue from a person who died of Covid-19, in a mouse model and in organoids - clusters of brain cells in a lab dish meant to mimic the brain’s three-dimensional structure. Zandi and his colleagues published research in July showing that some patients with Covid-19, the illness caused by the coronavirus, develop serious neurological complications, including nerve damage. “This data just provides a little bit more evidence that it certainly can.”ĭr. Michael Zandi, consultant neurologist at the National Hospital for Neurology and Neurosurgery in Britain. Scientists have had to rely on brain imaging and patient symptoms to infer effects on the brain, but “we hadn’t really seen much evidence that the virus can infect the brain, even though we knew it was a potential possibility,” said Dr. But several researchers said it was careful and elegant, showing in multiple ways that the virus can infect brain cells. The study was posted online on Wednesday and has not yet been vetted by experts for publication.
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