Dangerous appetite: The impact of Trypanosoma cruzi infection on the feeding and defecation behaviors of Triatoma dimidiata sensu lato (Latreille, 1811)

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BACKGROUND: Trypanosoma cruzi, the causative agent of Chagas disease, is primarily transmitted through the infected feces of blood-sucking bugs known as triatomines. As a result, its transmission is closely linked to the feeding and defecation behaviors of these insects. T. cruzi can alter various physiological processes in its vectors, including those involved in parasite acquisition, development, and excretion. This study aimed to assess the feeding and defecation behaviors of Triatoma dimidiata sensu lato (Latreille,1811), one of the main vectors, in relation to its T. cruzi infection status. METHODOLOGY/PRINCIPAL FINDINGS: Using both T. cruzi-infected and uninfected T. dimidiata, we measured various variables related to feeding and defecation behaviors. Notably, infected insects reached their host four times faster and began defecating twice as quickly as uninfected ones (282 ± 58 s vs. 1132 ± 198 s; 580 ± 120 s vs. 1220 ± 166 s, respectively), and these differences were significant. Among the bugs that defecated, 89% (16/18) of infected insects and 70% (14/20) of uninfected insects defecated during feeding. Moreover, among the bugs that defecated, a significantly higher proportion of infected insects defecated within the first 10 minutes after the start of feeding (11/18 = 61%) compared to uninfected insects, in which this behavior was less frequent (5/20 = 25%) and occurred later. Additionally, infected insects presented a significantly greater blood meal intake and feeding rate. CONCLUSIONS/SIGNIFICANCE: Overall, these findings suggest that T. cruzi alters the feeding and defecation behaviors of T. dimidiata in a way that could enhance its transmission potential.