Alexandre Yersin (1863-1943): discoverer of the plague bacillus, explorer and agronomist.

Alexandre Yersin was born in French Switzerland and later took French nationality. While a medical student he worked in Paris with Emile Roux to discover the exotoxin produced by the diphtheria bacillus. Two years after graduation, he left Paris for French Indochina where he was the first European to explore and map the central highlands of Vietnam. As a member of the French Colonial Health Service he was sent to Hong Kong in 1894 to investigate the outbreak of bubonic plague. He isolated from buboes the causative bacillus that later was named Yersinia pestis in his honour. In Vietnam, Yersin established a Pasteur Institute at the coastal village of Nha Trang where he lived for the rest of his life. He developed vaccines and antisera for both men and animals and, as an agronomist, he introduced the Brazilian rubber tree and Peruvian cinchona tree (for quinine) into the country. In Vietnam, as in France, the name of Yersin continues to be venerated.