The Transmission of Yellow Fever

On the Possibility of Immunity in Stegomyia Mosquitoes

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  • Yellow Fever Laboratory of the International Health Division of the Rockefeller Foundation, Bahia, Brazil


  1. 1.Stegomyia mosquitoes captured in houses in São Salvador, Bahia, Brazil, did not produce yellow fever when injected into Macacus rhesus.
  2. 2.Mosquitoes which had already digested a meal of immune blood, gave rise to no immunity when injected into or fed upon rhesus monkeys.
  3. 3.Mosquitoes which had already digested one or more meals of immune blood became infective after feeding on an animal with yellow fever.
  4. 4.In mosquitoes which had already digested a meal of infectious blood, the ingestion of immune blood had no influence on the subsequent development of infectivity.
  5. 5.Two batches of mosquitoes which fed on a mixture of infectious blood and immune serum did not become infective. The mixture itself produced yellow fever when injected directly into a monkey. A similar blood mixture with saline solution substituted for the immune serum proved infectious upon direct inoculation and gave rise to infectivity upon ingestion by two batches of mosquitoes.
  6. 6.Mosquitoes which took an interrupted meal, first upon an immune monkey and immediately afterward on an infected monkey, developed infectivity. A similar lot, which fed first on the infected and secondly on the immune animal, produced no disease when injected into a rhesus monkey. However, the latter was subsequently immune to a test dose of virus.