Infectious Diseases in Latin America and the Caribbean: Are They Really Emerging and Increasing? During 1995, infectious disease epidemics in Latin America and the Caribbean received wide publicity: dengue throughout the region, Venezue- lan equine encephalitis (VEE) in Venezuela and Colombia, and hemorrhagic fever in Nicaragua. Increased awareness of these diseases followed extensive reports in the scientific community about the threat of emerging infections (1,2). Are infectious diseases increasing in the region or are we simply seeing the results of better reporting of persistent problems? Analysis suggests that both factors are at work. Dengue and Dengue Hemorrhagic Fever During the 1950s and 1960s, under the leader- ship of the Pan American Health Organization (PAHO), most countries in the Americas success- fully reduced or eliminated infestation with Aedes aegypti, the principal vector of dengue and urban yellow fever. As a result, much of the Americas became free of dengue. Dengue transmission, however, persisted in many Caribbean islands and in some countries of northern South America that failed to control the vector; therefore, several out- breaks occurred during the 1960s and in sub- sequent decades (3). Ae. aegypti eradication programs, however, were not sustained and the mosquito reinfested all Latin American countries except Chile and Uruguay. As a consequence, dengue spread throughout the region, causing severe epidemics or even pandemics during the 1970s and 1980s. Currently, dengue is endemic in virtually all coun- tries with Ae. aegypti, and epidemics occur peri- odically. Between 1968 and 1980, only 60 suspected or confirmed cases of dengue hemorrhagic fever (DHF) were reported, all by five countries in and around the Caribbean. After the 1981 DHF out- break in Cuba, reports of DHF in the Americas markedly increased. The Cuban epidemic was the most notable event in the history of dengue in the Americas: almost 400,000 cases of dengue, over 10,000 cases of DHF, and 158 deaths were re- ported. The Cuban authorities implemented a successful vector control program and the country is still virtually free of Ae. aegypti. After this outbreak, cases of DHF continued to occur in the Americas, although at relatively low levels, until 1989 when another large epidemic with 2,500 cases of DHF occurred in Venezuela. Since then, Venezuela has reported large numbers of DHF cases every year, and in 1995 the country reported the largest outbreak of dengue/DHF in its history: almost 30,000 dengue cases and 5,000 DHF cases. Since 1968, 25 countries of the Americas have reported more than 35,000 confirmed or suspected DHF cases and approximately 500 deaths. In 1995, dengue and DHF activity in the region was higher than in any year except 1981. As of November, countries in the Americas had reported more than 200,000 dengue cases and 6,000 DHF cases, and approximately 90 deaths. Brazil has had the largest number of dengue cases, but more than 80% of the DHF cases occurred in Venezuela. The reinvasion of the Americas by dengue virus type 3, which had been absent for 16 years, has increased the threat of large epidemics and conse- quent risk for DHF (4). This serotype was isolated in Panama and Nicaragua at the end of 1994, and in 1995 it spread to other Central American coun- tries (except Belize) and Mexico, causing severe outbreaks. High levels of infestation with Ae. aegypti are common from the United States to Argentina, making it likely that dengue epidemics will increase in frequency and severity. Cholera Another disease reemerging in the Americas is epidemic cholera, which had been absent from this hemisphere for approximately 90 years before it was introduced into Peru in January 1991 (5). Since then more than 1 million cases of cholera have been reported in 20 countries in the region. Only Uruguay and the islands of the Caribbean have been spared. Though the annual total of reported cases has decreased since 1991, the dis- ease is persistent and problematic in several Latin American countries. Venezuelan Equine Encephalitis An outbreak of human infection with VEE virus associated with a large number of equine cases and deaths was detected in northwestern Vene- zuela in April 1995. The disease spread to the adjacent Colombian state of La Guajira in Sep- tember (6). Unusually heavy rains during 1994 and 1995 contributed to the epidemic by Commentary Vol. 2, No. 1 — January-March 1996 59 Emerging Infectious Diseases