Evolutionary ecology of Chagas disease; what do we know and what do we need?

Abstract

The aetiological agent of Chagas disease, Trypanosoma cruzi, is a key human pathogen afflicting most populations of Latin America. This vectorborne parasite is transmitted by haematophageous triatomines, whose control by large‐scale insecticide spraying has been the main strategy to limit the impact of the disease for over 25 years. While those international initiatives have been successful in highly endemic areas, this systematic approach is now challenged by the emergence of insecticide resistance and by its low efficacy in controlling species that are only partially adapted to human habitat. In this contribution, we review evidences that Chagas disease control shall now be entering a second stage that will rely on a better understanding of triatomines adaptive potential, which requires promoting microevolutionary studies and –omic approaches. Concomitantly, we show that our knowledge of the determinants of the evolution of T. cruzi high diversity and low virulence remains too limiting to design evolution‐proof strategies, while such attributes may be part of the future of Chagas disease control after the 2020 WHO's target of regional elimination of intradomiciliary transmission has been reached. We should then aim at developing a theory of T. cruzi virulence evolution that we anticipate to provide an interesting enrichment of the general theory according to the specificities of transmission of this very generalist stercorarian trypanosome. We stress that many ecological data required to better understand selective pressures acting on vector and parasite populations are already available as they have been meticulously accumulated in the last century of field research. Although more specific information will surely be needed, an effective research strategy would be to integrate data into the conceptual and theoretical framework of evolutionary ecology and life‐history evolution that provide the quantitative backgrounds necessary to understand and possibly anticipate adaptive responses to public health interventions.

Evolutionary perspectives on human infectious diseases: Challenges, advances, and promises

“…(), life‐history trait evolution theory and its attributes can help better understand the adaptive potential of triatomines—the vector of Chagas disease. The review by Flores‐Ferrer, Marcou, Waleckx, Dumonteil, and Gourbière () suggests that current knowledge of the determinants of high diversity and low virulence of the Trypanosoma cruzi parasite remains too limiting to design evolution‐proof strategies, while such attributes may be part of the future of Chagas disease control after the 2020 WHO's target of regional elimination of intradomiciliary transmission has been reached. The authors argue that the eco‐epidemiological relationships that build‐up the selective pressures at work have been assiduously studied over the last century, so that, combined with concepts and modeling inspired from life‐history evolution, a good evolutionary understanding could be rapidly gained.…”

The Influence of Environmental Cues on the Development of Trypanosoma cruzi in Triatominae Vector

“…Chagas disease is a key human vectorborne zoonotic disease that is endemic in 21 Latin American countries and the southern region of the United States (Bern et al, 2011;World Health Organization, 2014). In addition, new cases have been reported in Europe (Perez-Molina et al, 2011), Canada (Schipper et al, 1980), New Zealand and Australia (Jackson et al, 2014), mainly due to population mobility between the Americas and the rest of the world (reviewed in Flores-Ferrer et al, 2018). In the United States, it is also noteworthy that autochthonous human infections have been reported and that a considerable number of seropositive blood donors have been identified (Buhaya et al, 2015).…”

“…The chronicity of the pathogenesis of the disease has contributed to making it difficult to diagnose, compromising treatment. In addition, discontinuities in control initiatives launched in the 1990s have been responsible for a re-emergence of Chagas disease, which became a global economic and health issue (Flores-Ferrer et al, 2018).…”

Alteration of the social and spatial organization of the vector of Chagas disease,Triatoma infestans, by the parasiteTrypanosoma cruzi

“…Currently, 149 extant species have been described worldwide, and all of them are considered as potential vectors 4 . Most of them live in sylvatic habitats, and only a dozen of species are regarded as vectors of major epidemiological importance due to their capacity to live in the surrounding of the human dwellings where they find stable shelters and food abundance 5 . Triatoma infestans is the main vector in the Southern Cone of South America.…”

Presence of Rhodnius prolixus Stäl, 1859 (Hemiptera: Reduviidae) in Oaxaca, Mexico, ten years after the certification of its elimination

“…Triatomines, commonly known as kissing bugs, are hematophagous insects that belong to the subfamily Triatominae. Triatomines are important natural vectors of Trypanosoma cruzi that causes Chagas disease (Ballesteros-Rodea et al 2018, Flores-Ferrer et al 2018. A total of 151 species, representing fifteen genera, have been described globally (Justi and Galvão 2017).…”