Up to 100 of the world':s leading researchers into HIV/ Aids have lost their lives in the crash of the Malaysia Airlines crash in the Ukraine.
They were travelling from Amsterdam via Kuala Lumpur to Melbourne to attend the Aids 2014 conference which starts in the Australian city on Sunday.
Professor Richard Boyd, director of the Monash Immunology and Stem Cell Laboratories, told Guardian Australia he was "gutted" by the losses.
":There were some serious HIV leaders on that plane," he said. "This will have ramifications globally because whenever you lose a leader in any field, it has an impact. That knowledge is irreplaceable.
Trevor Stratton, an HIV/ Aids consultant, told the ABC: "The cure for Aids may have been on that plane, we just don't know. You can't just help but wonder about the kind of expertise on that plane."
Amongst the 298 people who died in the crash, which is believed to have been caused by a surface-to-air missile, was Professor Joep Lange (pictured above), Professor of Medicine at the Academic Medical Center, University of Amsterdam, a leader in his field and a former president of the International Aids Society, described by his colleagues as a "giant" of a man.
"Joep was a close colleague and friend of mine," Professor Peter Ries told the BBC. "Everyone here in Melbourne is in total shock at what happened.
"In the early eighties when this strange new disease hit Amsterdam, both Joep and I were training at the time and were confronted with this new disease which then went on to shape our scientific and medical careers.
"He's been really involved from the very beginning."
Officials confirmed that the conference will still go ahead in Melbourne on Sunday.
Pro-Russian rebels, the Ukraine and Russian governments have all denied shooting down the plane, which the UK and the USA claimed was hit by a surface-to-air missile over the town of Grabovo in eastern Ukraine.