SARS-Cov-2 viruses, the cause of Covid-19, infecting and degrading neurons (nerve cells), conceptual illustration. SARS-CoV-2 emerged in Wuhan, China, in December 2019 and spread throughout the world. The virus primarily causes a mild respiratory illness (Covid-19) that can develop into pneumonia and be fatal in some cases. In some cases the virus can also cause neurological symptoms including loss of smell (anosmia) and taste (ageusia) and inflammation of the brain (encephalitis).