Prominent AIDS expert Joep Lange was among up to 100 scientists, activists, researchers and health workers who died in the Malaysia Airlines MH17 crash in Ukraine.
They are thought to have been heading to this year’s international AIDS conference in Australia.
Prof. Joep Lange was a prominent and popular researcher and a former president of the International AIDS Society (IAS).
The IAS representatives said they would have “truly lost a giant”.
Delegates, who have already arrived at the conference in Australia said they were in “total shock”.
More than 14,000 scientists, campaigners and politicians are meeting at the AIDS 2014 conference, which starts in Melbourne at the weekend.
Joep Lange, was a professor of medicine at the University of Amsterdam, and has been involved in HIV research since the virus first emerged in the 1980s.
He trialed antiretroviral therapies, which have now transformed HIV into a manageable disease.
Prof. Joep Lange also worked on preventing the virus passing from mother to child during pregnancy and labor.
He is described as a leader in his field, and between 2002 and 2004 was the president of the IAS.
Malaysia Airlines plane, carrying 298 people, crashed in rebel-held territory in eastern Ukraine on Thursday.
Prof. Joep Lange’s partner, Jacqueline van Tongeren, was also reportedly on board.
The IAS said the conference would go ahead with “opportunities to reflect and remember those we have lost”.
It added: “The IAS is hearing unconfirmed reports that some of our friends and colleagues were on board the flight and if that is the case this is a truly sad day.
“The IAS has also heard reports that among the passengers was a former IAS president Joep Lange and if that is the case then the HIV/Aids movement has truly lost a giant.”
Another delegate, Glenn Thomas, a media spokesman from the World Health Organization (WHO), was also on board.
WHO spokeswoman Fadela Chaib said: “For the time being we would like to give his family time to grieve.
“We have lost a wonderful person and a great professional. Our hearts are broken. We are all in shock.”
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