Carrion's Disease: More Than a Sand Fly-Vectored Illness

Carrion’s disease is a biphasic illness (S1 Fig) caused by an infection of Bartonella bacilliformis, a bacterium that is transmitted through bites of certain phlebotomine sand flies in the Andean valleys of Peru and in some areas of Ecuador and southern Colombia [1,2]. The acute phase, called Oroya fever, is a serious, life-threating illness that mainly affects immunologically naïve populations, such as children. It is also of special concern in pregnant women, because high mortality rates have been described as well as miscarriages, preterm births, and fetal deaths [3]. In this acute phase, the absence or delay of antibiotic treatment may lead to fatal outcomes. In fact, it is considered that, in the pre-antibiotic era, the lethality of this illness ranked between 40% and 88% [1,2]. In the chronic phase, classically considered to occur in previously exposed inhabitants, B. bacilliformis induce endothelial cell proliferation, producing skin lesions called Peruvian warts. In this phase, the lethality is very low [1]. Additionally, the presence of asymptomatic carriers is frequent, although the real numbers remain uncertain because of the difficulty in detecting these subjects