Eco-epidemiology of rodent-associated trombiculid mites and infection with Orientia spp. in Southern Chile

Silva de la Fuente M.C., Pérez C., Martínez-Valdebenito C., Pérez R., Vial C., Stekolnikov A., Abarca K., Weitzel T., Acosta-Jamett G.

PLOS Neglected Tropical Diseases, 17 (1): e0011051 (2023).

S U M M A R Y

Scrub typhus is an emerging zoonotic infection caused by Orientia species in Asia-Pacific and recently discovered in Chile. The disease is transmitted by chigger mites; however, the knowledge on the vectors in Chile is scarce. We undertook a field study to capture wild rodents in three areas in southern Chile and to determine their infestation with chiggers infected with the bacteria. The study revealed that 89.4% of rodents carried trombiculid mites belonging to six species. The mite fauna and prevalence of Orientia showed geographical variations. Orientia DNA was found in four chigger species, mainly in two species of the genus Herpetacarus. The southernmost study area showed the highest prevalence of trombiculid infestation and infection with Orientia and must be considered a hot spot for scrub typhus in Chile. This study provides important new knowledge on the eco-epidemiology of scrub typhus in Chile.