in 1976 I discovered Ebola - now I fear an unimaginable tragedy

guardian |  Yes, and our first thought was: "What the hell is that?" The virus that we had spent so much time searching for was very big, very long and worm-like. It had no similarities with yellow fever. Rather, it looked like the extremely dangerous Marburg virus which, like ebola, causes a haemorrhagic fever. In the 1960s the virus killed several laboratory workers in Marburg, Germany.

Were you afraid at that point?

I knew almost nothing about the Marburg virus at the time. When I tell my students about it today, they think I must come from the stone age. But I actually had to go the library and look it up in an atlas of virology. It was the American Centres for Disease Control which determined a short time later that it wasn't the Marburg virus, but a related, unknown virus. We had also learned in the meantime that hundreds of people had already succumbed to the virus in Yambuku and the area around it.

A few days later, you became one of the first scientists to fly to Zaire.

Yes. The nun who had died and her fellow sisters were all from Belgium. In Yambuku, which had been part of the Belgian Congo, they operated a small mission hospital. When the Belgian government decided to send someone, I volunteered immediately. I was 27 and felt a bit like my childhood hero, Tintin. And, I have to admit, I was intoxicated by the chance to track down something totally new.

In the end, you discovered that the Belgian nuns had unwittingly spread the virus. How did that happen?

In their hospital they regularly gave pregnant women vitamin injections using unsterilised needles. By doing so, they infected many young women in Yambuku with the virus. We told the nuns about the terrible mistake they had made, but looking back I would say that we were much too careful in our choice of words. Clinics that failed to observe this and other rules of hygiene functioned as catalysts in all additional Ebola outbreaks. They drastically sped up the spread of the virus or made the spread possible in the first place. Even in the current Ebola outbreak in west Africa, hospitals unfortunately played this ignominious role in the beginning.

After Yambuku, you spent the next 30 years of your professional life devoted to combating Aids. But now Ebola has caught up to you again. American scientists fear that hundreds of thousands of people could ultimately become infected. Was such an epidemic to be expected?