Nevada health officials have confirmed the state’s first known case of a coronavirus variant that was originally identified in South Africa. The Nevada State Public Health Laboratory said Thursday the mutated version of the virus was confirmed a day earlier in a sample traced to a person who traveled from South Africa and began showing symptoms of COVID-19 when arriving in Reno. Experts say it’s another reason Nevadans need to be sure to keep their masks on and not to let their guard down as the state relaxes restrictions on businesses and public gatherings.