Dengue has been known in the Americas since the 18th century. During the 1960s and 1970s dengue pandemics occurred in the Caribbean, northern South America and Central America, and, during the 1980s and 1990s, virtually every country in the Americas experienced dengue epidemics. Dengue serotypes 1, 2 and 4 circulate widely and, since 1994, DEN-3 has circulated in Central America and Mexico. The...