On May 29, 1855, Scottish pathologist and microbiologist Sir David Bruce was born. Bruce investigated Malta fever (later called brucellosis in his honour) and African trypanosomiasis (sleeping sickness in humans and nagana in animals). He discovered the first protozoan parasite transmitted by insects, which was later named Trypanosoma brucei after him.
David Bruce was born in Melbourne, Australia, to David Bruce, a Scottish engineer and his wife Jane Russell Hamilton, who had emigrated to Australia in the gold rush of 1850. He was an only child. He returned with his family to Scotland at the age of five, where they lived in Stirling, Central Scotland. After visiting Stirling High School, in 1869 he began an apprenticeship for a warehouse firm in Manchester. However, after a bout of pneumonia he re-assessed his career and decided to study zoology but later changed to medicine at the University of Edinburgh in 1876, where he graduated M.B., C.M. in 1881.
After a brief period as a general practitioner in Reigate, Surrey, where he met and married his wife Mary, he entered the Army Medical School in Hampshire at the Royal Victoria Hospital, Netley, where he qualified the military examination in 1883 and joined the Army Medical Services. For his first post he joined the Royal Army Medical Corps in 1884 and was stationed in Valletta, Malta, where he and his wife were quartered in the Valetta Hospital, which had no facilities for research.
Impressed by Robert Koch’s discovery of the tubercle bacillus, Bruce decided to investigate Malta fever, which annually hospitalized many soldiers of the British garrison.  Altogether Malta fever was responsible for approximately 120,000 days of disease each year. Investigations showed that the disease was scattered across many different districts of the three islands. The density of the population was one of the highest anywhere in the world, and most families were crowded together in tiny houses. Contaminated water and poor hygiene were blamed for the disease.
Bruce purchased a microscope, and late in 1886 he found “enormous numbers of single micrococci” in the spleen of a fatally ill patient. Splenic pulp from four later patients, inoculated into Koch’s nutrient agar, yielded cultures of a slowly growing “micrococcus.” Bruce reported these findings about the organism, for which he proposed the name Micrococcus melitensis, first in 1887. Its bacillary morphology was unrecognized until Bang isolated Bacillus abortus in 1897. In 1920, on the suggestion of Feusier and Meyer, the generic term Brucella was adopted for these closely related microorganisms. The epidemiology of the disease remained a mystery until 1905, when Themistokles Zammit, a Maltese member of the Commission for the Investigation of Mediterranean Fever, the twelve-man team of experts headed by Bruce, implicated goat’s milk as the disseminating vehicle. The disease was conquered when goat’s milk was eliminated from the diet of the Malta garrison. The eponymous term “brucellosis” has now replaced such names as Malta, Mediterranean, and undulant fever.
In 1889 Bruce returned to England on leave, spending time discoursing in Koch’s laboratory while his wife acquired the latest techniques in microscopy, staining, and media making. Bruce was appointed Assistant Professor of pathology at the Army Medical School in Netley in 1889, and served there for five years. He returned to military field service in 1894 and was posted to Pietermaritzburg, Natal, South Africa. There, he was assigned to investigate the case of cattle and horse sickness (called nagana) in Zululand. In 1900, he joined the army commission investigating dysentery in military camps, at the same time working for the Royal Society’s sleeping sickness expedition.. In 1903, he identified the causative protozoa, and tsetse fly as the vector, of African trypanosomiasis (“sleeping sickness”).
Bruce served as a member of the Army Medical Service Advisory Board from 1902 to 1911. In 1914 he became Commander of the Royal Army Medical College, Netley, the position he held until his retirement as a Major-General in 1919. His closest collaborator was his wife, whose name appears on at least 30 of his 172 published papers.
David Bruce died four days after his wife in 1931, during her memorial service.
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