Jungle yellow fever was first recognized in eastern Colombia in the Intendencia del Meta in August of 1934, when an outbreak began in the vicinity of the town of Restrepo and continued through February, 1935. In the latter half of 1935, the disease appeared near the towns of Villavicencio and Acacías; and during the last eight months of 1936, cases occurred in all three regions. The year 1937 saw a few cases in the lower reaches of the rivers draining the previously involved areas and following these cases, no further ones were recognized in the Acacías-Villavicencio-Restrepo area proper up to the period covered by this report (July 1940).
The details of these outbreaks have been reported in a previous publication (1). A study of the findings led to the decision to initiate intensive investigations of the region, especially with respect to the arthropod and vertebrate fauna, to determine the relationships of these various forms of life to the epidemiology of the disease in man.