Naturally Acquired Yellow Fever in Wild Monkeys of Costa Rica

Abstract

Summary The acquisition of liver specimens for histopathologic examination from monkeys during the activity of the current epizoötic of yellow fever in Costa Rica has demonstrated that the progress of a wave of the sylvan (jungle) form of the disease can be traced in this manner as well as by similar studies on human fatalities. Out of 35 specimens obtained in Costa Rica, 24 are considered to exhibit the typical liver lesion. It was possible to secure satisfactory specimens in only about 10 per cent of the investigations of the reports of the presence of dead monkeys in the localities involved. An analysis of this experience will be applied to the formulation of a project designed to attempt to check the movement of the wave in the vicinity of La Ceiba, Honduras, in order to prevent involvement of northern Guatemala and Yucatan. The histopathologic features of yellow fever in the livers and kidneys of the arboreal primates closely parallel those found in man. The Councilman necrosis in the liver, as well as the heme casts, basophilic concretions and colloid material (“lime casts”) in the kidney tubules are highly resistant to postmortem autolysis. Intranuclear acidophilic inclusions (Torres bodies) were found in a large percentage of the monkey livers, and an evaluation of their diagnostic significance is now in progress.