discovery led others to further investigate and describe Pneumocystis as a distinct genus, which is now known to be a fungus. Chagas followed the literature closely and quickly confirmed the distinction, whereupon he again adopted the name Trypanosoma cruzi that he had originally coined. Pneumocystis is now linked to another disease, pneumocystis pneumonia, caused by one species (P. jirovecii), but the original Pneumocystis species seen by Chagas in guinea pigs has not yet been named as a separate species. Later life After the death of his mentor in 1917, Chagas accepted Cruz's directorship of the institute, a post he held until his death in 1934. From 1920 to 1924, he became the director of the Department of Health in Brazil. Chagas was very active in organizing special health-care and prevention services and campaigns for the Spanish flu epidemics, sexually transmitted diseases, leprosy, pediatrics, tuberculosis, and rural endemic diseases. He created a nursing school and was the founder of the concept of sanitary medicine, the first chairman of tropical medicine and the graduate study of hygiene. Chagas died in Rio de Janeiro from a heart attack in 1934 at 55 years of age. One of his sons, Carlos Chagas Filho (1910–2000), became an eminent and internationally recognized scientist in the field of neurophysiology and president of the Pontifical Academy of Sciences. Another son, Evandro Chagas (1905–1940), was also a physician and researcher in tropical medicine, who died in a plane crash at 35 years of age. His name is honoured by the important biomedical institution Instituto Evandro Chagas, in Belém, state of Pará. Nobel Prize controversy Chagas' discovery was recognized at home and abroad as one of the most important achievements in parasitology. He was twice nominated for the Nobel Prize in Physiology or Medicine (in 1913 and 1921), each time by only a single Brazilian nominator, but he never received the award. In 1913, 63 scientists were nominated for the Nobel Prize in Physiology or Medicine, the top two nominees having received nine and eight nominations, respectively. In 1921, 42 scientists were nominated for the award, the top four nominees having received 11, nine, seven, and seven nominations, respectively. A hundred years after the discovery of the disease, speculation still remains regarding the two official nominations of Carlos Chagas for the Nobel Prize. The reason why the prize was not awarded to Chagas may have been the strong opposition that