"Sadio Mane has tested positive for COVID-19 and is currently self-isolating according to the necessary guidelines," Liverpool said in a statement.
"The forward, who started and scored in Monday's 3-1 victory over Arsenal, has displayed minor symptoms of the virus but feels in good health overall.
"However, like with Thiago Alcantara, Liverpool Football Club are -- and will continue to -- follow all protocols relating to COVID-19 and Mane will self-isolate for the required period of time."
Liverpool had announced on Tuesday that summer signing Thiago tested positive for the virus after the midfielder did not feature in the club's 3-1 Premier League victory over Arsenal the previous day.
Liverpool's website had previously reported that his absence was due to a "minor fitness issue."
Liverpool will travel to Aston Villa for a Premier League match on Saturday before heading club football halts for the international break.