Rewiring the Vehicle: <i>Trypanosoma cruzi</i> Parasites Alter the Antennae of Their Triatomine Hosts

This study investigates the antennal phenotype of the kissing bug <i>Triatoma pallidipennis</i> (Stål), a primary vector of Chagas disease, by comparing <i>Trypanosoma cruzi</i>-infected and noninfected individuals. We examined the antennae of infected and noninfected N5 nymphs, as well as adult females and males, focusing on four types of sensilla (bristles, basiconic, thin-walled trichoid, and thick-walled trichoid) across three antenna segments (pedicel, proximal flagellum, and distal flagellum). We found differences in sensilla abundance across the antennal segments, with the proximal flagellum showing the highest abundance, followed by the distal flagellum, and the pedicel having the least. Infection demonstrated that males had more chemosensilla than females. We observed a trend in the infected males and nymphs with an increased variation in sensilla types. These antennal modifications are related to previous results in this species whereby infected bugs were found to be more active and capable of finding a human odor compared to noninfected animals. Thus, infection-related changes in antennal phenotype may underlie <i>T. pallidipennis</i>' sensory capabilities, which may indirectly facilitate the spread of the parasite.