To prepare the vaccine the team used irradiated larvae of the lungworm parasite (Dictyocaulus viviparus). The parasite is a major cause of lung disease (known as parasitic bronchitis) in cattle in temperate countries of the world. This group of Glasgow scientists showed that if the larvae of the parasite were damaged (attenuated) by exposure to X-rays a powerful and long lasting immunity could be induced.

The clinical trials of the vaccine were undertaken across Scotland by the Glasgow scientists and in the final stages involved 8,000 calves on 204 farms.

Dictol is the commercial name of the vaccine and it went into production in the 1960s and has been in continuous production since then. Over the past 50 years, millions of cattle have been successfully vaccinated throughout Europe. It remains the only successful vaccine of its kind in the world.

The research in Glasgow not only led to a major veterinary breakthrough but greatly stimulated attempts in many countries to produce vaccines against other parasitic infections of animals and man.