Eco-epidemiological Insights into Psammolestes arthuri: Trypanosoma cruzi Infection and Feeding Behavior in Casanare, Colombia

Abstract

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, affects millions of people and is primarily transmitted by triatomine bugs. Although Psammolestes arthuri has been traditionally classified as a secondary vector due to its predominantly ornithophilic feeding habits, recent findings suggest that its ecological and behavioral traits may enhance its epidemiological relevance. We hypothesized that P. arthuri exhibits natural infection rates, flexible feeding behavior with frequent mammalian contacts, and spatial variation in parasite load that challenge its conventional classification. To test this, we assessed T. cruzi infection prevalence, parasite load, and blood meal sources in 61 specimens collected from two municipalities in Casanare, eastern Colombia—San Luis de Palenque (n = 43) and Tauramena (n = 18)—between April and October 2023. Infection was determined by qPCR, and feeding sources were identified by 12S rRNA gene sequencing. The results revealed a 68.8 % infection rate with a mean parasite load of 70.40 parasites/mL, with adult males showing the highest loads. Feeding analysis indicated a predominance of Anhinga anhinga (64.9 %), followed by Phalacrocorax brasilianus (6.8 %), Homo sapiens, and other species. The detection of human blood, particularly in nymphs, suggests behavioral adaptation toward opportunistic feeding in proximity to human dwellings. These findings support the hypothesis that P. arthuri may contribute to local transmission dynamics of T. cruzi and highlight the need to consider both avian and mammalian hosts in Chagas disease surveillance.