Oswaldo Cruz

As Director-General of Public Health, led Rio de Janeiro's campaigns against yellow fever, plague and smallpox, acting on the mosquito theory with brigades that removed breeding sites; recorded yellow fever cases fell from 39 in 1906 to none in 1908.

Directed the Manguinhos serum institute from 1902, turning it from a plague-serum producer into a centre for vaccine production, research and training that was later renamed for him and became Fiocruz.

Won the gold medal at the 1907 International Congress on Hygiene and Demography in Berlin for Rio's sanitation work, and later directed expeditions and sanitation campaigns in the Amazon and on the Madeira-Mamoré railway.

At the height of the November 1904 unrest against compulsory smallpox vaccination, Cruz offered his resignation, but President Rodrigues Alves replied that the measures were wanted, and the sanitation work continued.

This is consistent with a professional who stayed with his public-health measures under intense hostility, with the government's backing playing a large part. Persistence

For the yellow-fever campaign Cruz divided Rio into ten districts, sent brigades to inspect building by building and record cases, and combined fines and demolition orders with explanatory leaflets, although his hoped-for 1,200 agents became only 85.

This is consistent with a methodical, structured approach to public health whose coercive style carried social costs. Planning Orientation

In 1909 Cruz left the Director-Generalship of Public Health to concentrate on the Manguinhos institute, which was renamed for him, and from there launched expeditions that documented health conditions in the country's interior.

This is consistent with a shift from managing city campaigns toward building research capacity and investigating national health problems. Impact Motivation