Yellow fever: The present situation (October 1938) with special reference to South America

Abstract

The Rockefeller Foundation embarked, in 1915, on a programme of eradicating yellow fever from the Americas, by collaborating in the organization of anti- Aëdes aegypti measures in the few remaining seed-beds of infection. This programme, apparently gave expected results for many years in various countries, but failed to eradicate yellow fever from Brazil, where two previously unrecognized epidemiological types, rural yellow fever transmitted by Aëdes aegypti and jungle yellow fever occurring in the absence of this mosquito, were found to be responsible for maintaining non-urban endemicity. The problem of rural aegypti-transmitted yellow fever has been solved by extension of anti-aegypti measures to the rural areas of north-east Brazil, the only region in South America where this type has been found. Jungle yellow fever is not limited to Brazil, but also occurs in Paraguay, Bolivia, Peru, and Colombia and almost surely in Ecuador, Venezuela, Panama, British Guiana and Dutch Guiana. Jungle yellow fever has been observed in South Brazil as a wavelike phenomenon involving many of Brazil's richest districts in the years 1934 to 1938. The control of yellow fever in Brazil is based on viscerotomy, anti-aegypti measures and vaccination. As a result of viscerotomy over 140,000 liver tissues have been examined for lesions of yellow fever since 1930. Costs of anti-aegypti measures have been greatly reduced in recent years. Over 800,000 persons have been vaccinated during the first nine months of 1938 with satisfactory results and without serious complications of any kind. The threat of extension of yellow fever from present endemic regions of Africa to the ports of East Africa and to the Orient is sufficiently important to call for a consideration of viscerotomy, anti-aegypti measures and vaccination to meet it.