Transition in the Cause of Fever from Malaria to Dengue, Northwestern Ecuador, 1990–2011

Sara G. Cifuentes¹, James Trostle, Gabriel Trueba, Meghan Milbrath, Manuel E. Baldeón¹, Josefina Coloma, and Joseph N.S. Eisenberg

Author affiliations: Universidad San Francisco de Quito, Quito, Ecuador (S.G. Cifuentes, G. Trueba, M.E. Baldeón); Trinity College, Hartford, Connecticut, USA (J. Trostle); University of Michigan, Ann Arbor, Michigan, USA (M. Milbrath, J.N.S. Eisenberg); University of California Berkeley, Berkeley, California, USA (J. Coloma)

Abstract

In tropical areas, the predominant cause of fever has historically been malaria. However by 2011, among febrile patients in northwestern Ecuador, dengue was identified in 42% and malaria in none. This finding suggests a transition in the cause of fever from malaria to other illnesses, such as dengue.

Clinical and public health decisions about infectious diseases depend on the specific agents of infection. The predominant cause of fever in tropical areas has historically been malaria. However, dengue is becoming more of a concern as its geographic range expands, despite efforts to control the spread of the main vector, Aedes aegypti mosquitos (1). In the past 2 decades, dengue has expanded from urban areas, the focal point of endemic and epidemic activity, to more rural regions (2). At about the same time, malaria incidence has decreased by 17% globally; in Ecuador, it decreased by > 75% (3). Etiologic transitions like these require timely changes in treatment and intervention strategies.