Abstract

PIP: In 1983 the total number of jungle yellow fever cases in the Americas was one of the lowest in recent years. There were 2 outstanding occurrences during the year, representing the end of an epidemic that had taken place in the Santa Cruz region of Bolivia in 1981 and 1982. The small number of cases, in contrast with previous epidemics, was the result of an increasing number of vaccinations in the affected regions. At a Pan American Health Organization Seminar on the treatment and laboratory diagnosis of yellow fever held in Brazil in 1984, participants reviewed the epidemiologic situation in places where yellow fever poses a serious and ongoing public health problem. At this time, the general yellow fever situation in each of the affected countries of the Americas--Bolivia, Brazil, Colombia, Ecuador, and Peru--is as follows. Yellow fever is endemic in 2/3 of Bolivia, primarily in the south. Males are affected more often (78%) than females (22%). Generally, the patients are adults, but during a recent epidemic in the Rincon del Tigre area 14.5% of the cases occurred in children under age 4 and 11.6% in children 5-9 years. In Brazil, the endemic zone comprises states in the northern, central, and western regions and also in the western strips of the State of Maranhao. The disease occurs rarely among children under age 11, and 70% of the victims are men ranging in age from 15-40 years who are working in the jungle; only 15% of the cases occur among women. Colombia's last urban yellow fever case occurred in 1929. At this time yellow fever is endemic in the eastern plains, which form part of the Amazone and Orinoco basins. It spreads in the form of epizootic and epidemic waves through the forests at the foot of the eastern cordillera. Yellow fever is endemo-epidemic in the northern and central jungle of Peru. Over 600 cases were reported from 1960-82. These cases occurred during the rainy season of January to May. Vaccination campaigns have been intensified during the last 3 years. Yellow fever is enzootic in the gallery forests of the tropical plain of the Orinoco Basin, Venezuela. The 15-55 age group is the group usually at risk, but 2% of the cases occur in children under age 5 and 2.8% in children under age 10. Between 1965-84, the countries of the Americas reported 2238 cases to the Pan American Health Organization, but this figure provides an incomplete idea of the real incidence of yellow fever.