Salah initially tested positive for coronavirus last Friday and did not play for Egypt in their Africa Cup of Nations qualifiers against Togo on Saturday and Tuesday.
The 28-year-old has tested positive again on Wednesday, according to a statement from the Egyptian FA.
“Today, Mohamed Salah, the star of the national team and the English club Liverpool, made a new swab to detect the Covid-19 virus, but its result was positive,” a statement from the Egyptian FA read.
This means that Salah will miss Liverpool’s Premier League game against Leicester City this weekend.
The defending English champions will take on the Foxes at Anfield on Sunday evening.
Jurgen Klopps side are third in the Premier League table at the moment with 17 points from eight matches, just a point behind leaders Leicester.
Salah has scored eight goals in eight Premier League matches and has scored two goals and provided one assist in three Champions League games so far this season.