CIENCIASMEDICASNEWS: Ahead of Print - Scrub Typhus in Continental Chile, 2016–2018 - Volume 25, Number 6—June 2019 - Emerging Infectious Diseases journal

Author affiliations: Universidad del Desarrollo, Santiago, Chile (T. Weitzel); Pontificia Universidad Católica de Chile, Santiago (C. Martínez-Valdebenito, K. Abarca); Universidad Austral, Valdivia, Chile (G. Acosta-Jamett); Naval Medical Research Center, Silver Spring, Maryland, USA (J. Jiang, A.L. Richards)

Abstract

Endemic scrub typhus was recently detected on Chiloé Island in southern Chile. We report a series of cases, acquired over a wide geographical range in continental Chile during 2016–2018, demonstrating that this emerging rickettsial infection is also found on the mainland of South America.

Scrub typhus is a vectorborne zoonosis caused by Orientia spp. bacteria; infection carries a potentially severe outcome (1). Although widely underrecognized, scrub typhus is considered one of the most important rickettsial infections worldwide in terms of prevalence and severity (2). Until recently, scrub typhus was associated with only a single species, O. tsutsugamushi, which is transmitted by larvae of trombiculid mites (chiggers) and threatens >1 billion human inhabitants within the so-called tsutsugamushi triangle in the Asia–Pacific region (1). Since 2006, the discoveries of scrub typhus in 4 patients on Chiloé Island in Chile (3,4) and in 1 patient from Dubai, United Arab Emirates (5), have suggested the emergence of the disease farther afield (6). This change of paradigm has been reinforced by recent studies mainly from Africa (7). The emergence of endemic scrub typhus on Chiloé Island has been confirmed by ongoing studies of our working group in Chile (8,9). Whether this disease is only endemic to Chiloé Island or has a wider distribution is unknown. We report 9 patients who had scrub typhus diagnosed after visiting different regions of continental Chile during 2016–2018.