Dr. Wolfred David Emelius Nelson was born on April 10, 1846, in Montreal, Quebec, grandson of Wolfred Nelson (1791-1863), a Montreal doctor and politician.

He was a physician, sanitation expert, and author. He was educated at McGill University and began his practice in Canada. In 1880, he moved to Panama for 5 years. He also spent years in South and Central America where he was collecting data on climatology and tropical diseases. In 1899, he moved to New York to practice. Dr. Nelson made yellow fever his special study and wrote exhaustively on this and other tropical diseases. In 1904, he went to Cuba as a special sanitary commissioner and for his work in the prevention of tropical diseases, Queen Isabella of Spain bestowed upon him the title of Commander of the Order. He was a member of the New York State Medical Society, the Natural History Society of Montreal, and was elected a fellow of the Royal Geographic Society in 1894. He was a founder of the Canadian Society of New York and a founder and president of the New York Graduates Society of McGill University.

In 1875, he married Frederika Woodbridge De Long (1853–). He died on January 15, 1913, in New York, New York.