AIDS researchers and advocates are used to dealing with death, they say, but that hasn't made the last 48 hours any easier.
An estimated 12,000 scientists, medical workers, advocates and policymakers are traveling to the 20th International AIDS Conference in Melbourne, Australia — a "mega event" for their field — amid the grim news that dozens of their colleagues, including a top researcher, were killed in the downing of Malaysia Airlines Flight 17 over Ukraine.
The loss is certain to cast a shadow over the conference, members of the community said, calling the blow immeasurable and tragic.
"It's like a train has gone off the track," said Terri Ford, chief of global advocacy and policy for the AIDS Healthcare Foundation, who arrived in Melbourne on Thursday. "It's hard to absorb what has happened."
Confirmation of the names of the dead rolled in slowly, but by Friday, the conference attendees knew they had lost at least one superstar.
Joep Lange, a former president of the International AIDS Society and a professor of infectious diseases at the University of Amsterdam whose leadership spanned the history of the epidemic, was confirmed among the dead.
In addition to Lange, a colleague, Jacqueline van Tongeren of the Amsterdam Institute for Global Health and Development, was confirmed among those who perished; as was Glenn Thomas, 49, a spokesman for the World Health Organization. Both were headed to the AIDS conference.
The International AIDS Society late Friday confirmed the names of three more colleagues who were aboard Flight 17: Pim de Kuijer of Stop AIDS Now, and Lucie van Mens and Maria Adriana de Schutter, both of AIDS Action Europe.
Investigators were still sorting through lists to identify all 298 passengers and crew members who died when the Boeing 777 was shot down Thursday over eastern Ukraine en route from Amsterdam to Malaysia. The U.S. has said it appears pro-Russia Ukrainian separatists were responsible.
More than half of the victims were identified as Dutch, and one had dual American-Dutch citizenship.
They came from 10 countries and included scientists, amateur athletes, tourists and passengers heading home.
President Obama on Friday identified the only known American citizen on the downed plane as Quinn Lucas Schansman, who also had Dutch citizenship. Another passenger with American connections, Karlijn Keijzer, 25, of Amsterdam, was a doctoral student in chemistry at Indiana University and an avid rower.
Obama singled out the AIDS group as a special loss.
"On board Malaysian Airlines Flight MH17, there were apparently nearly 100 researchers and advocates traveling to an international conference in Australia dedicated to combating AIDS/HIV," he said.
"These were men and women who had dedicated their own lives to saving the lives of others, and they were taken from us in a senseless act of violence."
"In this world today, we shouldn't forget that in the midst of conflict and killing, there are people like these — people who are focused on what can be built rather than what can be destroyed; people who are focused on how they can help people that they've never met; people who define themselves not by what makes them different from other people but by the humanity that we hold in common," Obama said. "It's important for us to lift them up and to affirm their lives. And it's time for us to heed their example."
AIDS researchers and advocates echoed his sentiments, calling the impact on their field "unquantifiable" and the loss of Lange particularly so.
Lange was best known for participating in work in the 1990s that helped discover the effect of combination therapy, the uses of multiple drugs to suppress HIV, which causes AIDS.
Today, millions of people around the world take a variety of antiretroviral medications in such drug cocktails to help keep the virus at bay.
Before such therapies were available, "AIDS was a death sentence," said Thomas Coates, an expert on HIV prevention who directs the UCLA Center for World Health.
More recently, Lange's work had focused on improving access to HIV medication to disadvantaged populations around the world.
"His loss is more than just a summary of his efforts and his papers," said Columbia University professor of medicine Scott Hammer, an advisor to several of Lange's projects. "He was not shy about speaking truth to power. He spoke softly and carried a lot of moral heft. He was equally compassionate, and driven for his mission."
Hammer and other scientists said, however, that until it becomes clear who else was on the plane, it would be hard to assess the incident's broader impacts.
"It's hard to know what it means for the field," said Dr. H. Clifford Lane, deputy director for clinical research and special projects for the National Institutes of Health's National Institute of Allergy and Infectious Diseases. "But typically at these meetings, we try to have the senior leaders and the leaders of the next generation. If some of the members of that next generation were on that plane, it's extraordinarily devastating."
He added that he believed the tragedy would inspire remaining researchers, health workers and advocates to reexamine their goals, "remember what they've lost, and do their best to honor [colleagues'] memories."
AIDS researchers and advocates who knew Lange said they remained anxious, awaiting further word on other colleagues who might have been on the flight.
Harvard School of Public Health professor Richard Marlink said he had spoken by phone with associates who were in Melbourne for the conference. They reported that "everyone is shocked and saddened, and the air is quiet, and small memorial signs are starting to appear," he said.