Joshua Arthur Nunn, army veterinary surgeon, qualified (MRCVS, London) in 1877 and that same year also acquired a Certificate in Cattle Pathology from the Royal Agricultural Society. He joined the British Army Veterinary Division in 1877 and enjoyed a distinguished career in Afghanistan and India. From 1880 to 1885 he did veterinary work as a civil servant on special duty to the Punjab government, during which he wrote valuable reports on animal diseases in various districts and also lectured at Lahore Veterinary College. In 1886 he was elected a Fellow of the Royal College of Veterinary Surgeons (FRCVS).
After completing short courses in bacteriology in Cambridge and Paris Nunn was sent to South Africa from January 1887 to October 1888 to study African horse-sickness, mainly in Natal. He returned to India in January 1889 to become principal of the Punjab Veterinary College for six years. In 1895 he proceeded to England and became a Companion of the Order of the Indian Empire (CIE). In England he studied law and after being called to the Bar in November 1899 worked as an advocate of the supreme court in the Transvaal during part of the Anglo-Boer War (1899-1902). From 1901 to 1904 he was deputy director of the Army Veterinary Department in England. From August 1905 to June 1906 he returned to South Africa as principal (military) veterinary officer, and then once again proceeded to India for a short time.
Nunn published three reports in the Veterinary Journal relating to horsesickness, the first two stating that he could not confirm the popular belief that Anthrax and African horsesickness are the same disease. In his third report he reverted to Rutherford's idea that the two disease are the same but that there are four distinct manifestations thereof. Two other reports, published as pamphlets, were based on his first tour of duty in South Africa: Notes on horsebreeding in South Africa (Cape Town, 1888), and Reports on the horse supply of South Africa (London, 1888). Among his other publications were Notes on stable management in India (1896), Lectures on saddlery and harness (1902), Veterinary first aid in cases of accident or sudden illness (1903), diseases of the mammary gland of the domestic animals (1904), and Veterinary toxicology (1907). He was joint editor of the Veterinary Journal from 1893 to 1906.