Willy Burgdorfer was a Swiss-born medical entomologist who gained international recognition for discovering the bacteria that causes Lyme disease. He spent decades researching the connections between animal and human diseases caused by the bites of fleas, ticks and mosquitoes.
In 1982, while he and another researcher were studying deer ticks in the hope of uncovering the cause of a spotted fever outbreak in New York, Burgdorfer found the micro-organisms called spirochetes which would prove to be the cause of Lyme disease.
The infection caused children living near Lyme, Connecticut, to develop rheumatoid arthritis. It also causes heart and neurological problems. Burgdorfer's research opened doors to diagnose and treat the disease and the spirochete later was named Borrelia burgdorferi in his honour.
His previous work on relapsing fever helped him recognise the cause of Lyme disease, his colleague and friend, Dr Tom Schwan, said, adding that Burgdorfer called his most famous discovery "serendipity". It was made, he said, while looking for something totally different and remains a testament to Burgdorfer's abilities as a scientist.
"It was a 'What in the hell? What's in that smear?' moment," he said. "And then my work on relapsing fever as a Swiss student came back. I said to myself, 'Willy, these are spirochetes!'"
Wilhelm Burgdorfer was born in Basel in 1925 and gained a PhD in zoology, parasitology, and bacteriology from the University and the Swiss Tropical Institute there. He also served in the Swiss Army for three years.
In 1951 he moved to the Rocky Mountain Laboratory in Montana as a research fellow in 1951. He joined the staff there as a medical entomologist six years later, when he also became an American citizen.
He retired in 1986 after writing more than 225 scientific papers on subjects such as relapsing fevers, plague, tularemia, Colorado tick fever, Rocky Mountain spotted fever and other bacterial and viral diseases. He also travelling the world giving lectures.
He won numerous awards, including the Robert Koch Gold Medal for excellence in biomedical sciences in 1988, and he received an honorary medical degree from the University of Marseille in 1991.
Wilhelm Burgdorfer, medical entomologist: born Basel 27 June 1925; married 1953 Dale See (died 2005; two sons), secondly Lois Rohr; died Hamilton, Montana 17 November 2014.Reuse content