Yellow fever has been an important and serious disease problem in Bolivia. Records exist of epidemics probably due to yellow fever as far back as 1867. Since the establishment of the Yellow Fever Service, which introduced modern methods of diagnosis and control in 1932, records have been obtained of 9,635 cases; of these 5,144 occurred in the presence of A. aegypti and 4,491 were due to jungle yellow fever.
A. aegypti was found in 65 localities in Bolivia, of which 45 were in a small area around the city of Santa Cruz and the rest at river ports or at isolated places along travel routes. The highest altitude at which these mosquitoes were found was 580 meters.
The last epidemic transmitted by A. aegypti occurred in 1936 at Terevinto, which is west of the city of Santa Cruz, following some cases of jungle yellow fever outside the town. Aegypti were eliminated from Bolivian territory by 1943, but reinfestations of frontier localities and of one inland place occurred until 1948. No aegypti have been found since that time.
Jungle yellow fever cases occur periodically in five endemic areas, of which one is in La Paz and four in the Department of Santa Cruz. Isolated cases discovered by viscerotomy, or small epidemics, have occurred in various places outside the well-known endemic areas. A serious outbreak occurred in a new epidemic area in Chuquisaca early in 1950, with yellow fever occurring in most of the endemic areas at the same time.
The disease was widespread and unusually serious in 1935–36 and again in 1949–50, whereas in the interim the incidence of yellow fever in human beings was much lower, suggesting a possible cycle in prevalence.
Jungle yellow fever epidemics are invariably associated with notably increased Haemagogus populations. Three species of Haemagogus have been identified from Bolivia and it is expected that another species will be found.
A systematic program is under way for vaccinating during the next four or five years the population in that part of the country lying below an altitude of 1,600 meters. The permanent maintenance of an efficient yellow fever service is the only means, at present, of keeping the disease in abeyance.
Supported jointly by the Ministry of Health of Bolivia and The Rockefeller Foundation.