Yellow fever known as "mosquito inspectors" fiercely worked to combat yellow fever throughout Rio by spraying, exterminating rats, improving drainage, and destroying unsanitary housing. Ultimately, the city's sanitation and renovation campaigns reshaped Rio de Janeiro's neighborhoods. Its poor residents were pushed from city centers to Rio's suburbs, or to towns found in the outskirts of the city. In later years, Rio's most impoverished inhabitants would come to reside in "favelas". During 1920–23, the Rockefeller Foundation’s International Health Board undertook an expensive and successful yellow fever eradication campaign in Mexico. The IHB gained the respect of Mexico’s federal government because of the success.
Yellow fever in Buenos Aires made of wood or clay and straw. In addition to the epidemic of yellow fever that we have mentioned, there were outbreaks of cholera in 1867 and 1868, which killed hundreds of people. On 27 January 1871, three cases of yellow fever were diagnosed in Buenos Aires. They were all in the San Telmo neighbourhood, which is full of tenements. From this date on, many more cases were registered, mostly in that neighbourhood. The doctors Tamini, Salvador Larrosa and Montes de Oca warned the City Commission of the outbreak of an epidemic. But the Commission, under the leadership of Narciso