The U.S. has a larger population of Chinese than Brazil. Many went to the city of Wuhan to celebrate the Chinese New Year and brought back the virus. I don’t think as many brought back the virus to Brazil. New York City contains the largest ethnic Chinese population outside of Asia, totaling 682,265. New York has been described as the epicenter of the virus infection in the U.S. Los Angeles has more than 66,782 ethnic Chinese and San Jose has 63,434 ethnic Chinese. The Seattle-Tacoma area has 45,000 ethnic Chinese population. Brazil has about 350,000 ethnic Chinese. Do you think this has something to do with the degree of infection in the U.S.?
Another difference is the exceptional mobility of the US population.