The Miami-Dade medical examiner has determined that renowned AIDS researcher Dr. Mark Wainberg died from acute asthma exacerbation.

Dr. Wainberg was at a beach in suburban Miami on Tuesday when he had trouble swimming, and was pulled out of the water by his son. He died in hospital.

Now friends and colleagues are trying to absorb the shock of the loss of a man known around the world who took part in an international conference just last week.

Dr. Wainberg was the director of the Lady Davis research institute at the Jewish General Hospital, and Dr. Gerald Batist is taking over on an interim basis.

"Everyone feels an absence, there's a real deep hole in all of us both personally and scientifically, we're hearing globally from people around the world," said Dr. Batist.

The McGill University flag in front of the hospital was lowered to half-mast Friday in recognition of Dr. Wainberg's tireless work for decades.

Immunologist Dr. Mark Weiss calls Wainberg a historic figure in the world of HIV/AIDS who promoted acceptance.

"Even in the medical community, when at the beginning not everybody was really willing to treat people with AIDS and people were scared, but he taught us very quickly that we need to treat AIDS like any other condition. He was right and that I think was a major contribution," said Dr. Weiss.

Dr. Christos Tsoukas, director of Clinical Immunology at the MUHC, was on the front lines of HIV research with Wainberg in the 1980s.

"We spent a lot of time together over the next 35 years," said Dr. Tsoukas.

They launched the McGill AIDS Centre, with Wainberg in the lab and Tsoukas conducting clinical trials.

Their work accumulated accolades and honours as they developed successful treatments, but Tsoukas remembers Wainberg for his compassion.

"He had a sense of ethics that went beyond what most other people have. He always seemed to do the right thing, he never criticized everyone, he had a vision and pursued it and he was a pleasure to be around and to work with him and to try and make the world a better place," said Dr. Tsoukas.

Batist says that Wainberg's research continued to generate sparks through the decades.

"If the scope of our ingenuity tends to, for most people, decline with age and we focus on a couple of things... that was not Mark. His scope of ingenuity kept expanding."

Weiss agreed that Wainberg was never short of ideas.

"When you have something sad and dark like this you always try to remember the good part - and the good part is that he's going to be with us everyday when we practice medicine and we treat people with HIV," said Weiss.

Funeral services for Dr. Wainberg take place Friday at 1 p.m. at Tifereth Beth David Jerusalem Congregation in Cote Saint Luc.

Due to Passover, the traditional Jewish period of mourning, shiva, will begin on Wednesday April 19.