South Africa's Louis Oothuizen has become the third former major champion to withdraw from the Rio 2016 Olympic golf tournament. Following in the footsteps of world number seven Adam Scott and former world number one Vijay Singh, Oosthuizen has pulled out of the event – the first to be staged in the summer Games since 1904 – after discussions with his family.

Three-time major winner Singh confirmed he would not be participating in Rio last week due to fears over the outbreak of Zika, a virus that is transmitted by mosquitoes and has been linked to birth defects in new-born children. Scott, who had previously labelled the tournament an "exhibition", followed the Fijian on Wednesday in order to focus on the PGA Tour.

The 2010 Open champion will be replaced by Charl Schwartzel as one of the two direct entrants from South Africa, alongside Branden Grace. The top 15 players in the world, with a maximum of four from each country, automatically win entry into the 60 player field for the stroke-play event. The remaining places go to the highest-ranked players whose countries do not already have two direct entrants.

"I have always represented South Africa with pride so didn't make my decision without a great deal of thought," said Oosthuizen in a statement. "I would like to wish our golfers and all other athletes competing in Brazil all the very best for success."

A third withdrawal from the men's competition will draw more criticism of the inclusion of a sport at the Rio Games, which is not regarded as the pinnacle of the calendar, with many questioning its role in a year with four major championships and the Ryder Cup. Scott has come in for significant criticism for pulling out, including from four-time Olympic swimming champion Dawn Fraser.

"My decision has been taken as a result of an extremely busy playing schedule around the time of the Olympics and other commitments, both personal and professional," said Scott. "I have informed the Australian team captain and relevant authorities, who are understanding of my position and I wish the Australian Olympic team the very best of luck in Rio."