The Swiss researcher who gained international recognition for discovering the bacteria that causes Lyme disease has died in the US.

A spokesman at the Daly-Leach Chapel in Montana said Wilhelm ‘Willy’ Burgdorfer died from complications of Parkinson’s disease. He was 89.

Burgdorfer was educated in Switzerland. He later went to the Rocky Mountain Laboratory in Montana as a research fellow in 1951 and joined the staff as a medical entomologist six years later.

He spent decades resear-ching 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.

His previous work on relapsing fever helped him recognise the cause of Lyme disease, said colleague and friend Tom Schwan. The latter said Burgdorfer called his most famous discovery “serendipity”. It was made while looking for something totally different and is a testament to Burgdorfer’s abilities as a scientist, he said.

The infection caused children living near Lyme, Connecticut, to develop rheumatoid arthritis. It also causes heart and neurological problems. The spirochete later was named Borrelia burgdorferi, after Burgdorfer.

Burgdorfer’s research opened doors to diagnose and treat the disease, Schwan said.

He retired in 1986 after authoring more than 225 scientific papers and travelling the world giving lectures and working with fellow scientists.

Burgdorfer won numerous awards, including the Robert Koch Gold Medal for excellence in biomedical sciences in 1988, and received an honorary medical degree from the University of Marseille in France in 1991.