Background Chagas disease remains a major public health risk in Bolivia, particularly among rural indigenous communities. Here we studied the cultural perception of the triatomine vectors and Chagas disease among selected rural and urban ethnic groups from different socio-economic and geographical milieus. We focused on the indigenous communities in the Bolivian Chaco where the disease is hyperendemic. Methods A cross-sectional study using field observations and structured interviews was carried out among 480 informants in five different regions of Bolivia. Additional semi-structured interviews were conducted. Statistical analyses were performed to determine the correlation of socio-economic variables and indigenous Chagas disease knowledge systems. A total of 170 domestic Triatoma infestans vectors were collected and infection with Trypanosoma cruzi was analyzed by real-time PCR. Results Triatomine bugs were associated with Chagas disease in 70.2% ( n = 480) of the responses (48.0% Ayoreo, 87.5% Chiquitano, 83.9% Guaraní, 72.2% Quechua, 46.1% La Paz citizens and 67.7% Santa Cruz citizens). Generally, indigenous informants have been educated on the association between triatomine bugs and Chagas disease by institutional anti-Chagas disease campaigns. While communities were largely aware of the vectors as a principal mode of disease transmission, rather unexpectedly, health campaigns had little influence on their prevention practices, apparently due to cultural constraints. Overall, 71.9% of the collected domestic vectors in the Chaco region were infected with T. cruzi , matching the high infection rates in the indigenous communities. Conclusions Among the Guaraní, Ayoreo and Quechua communities, the groups living in traditional houses have not integrated the scientific knowledge about Chagas disease transmission into their daily hygiene and continue to cohabit with T. infestans vectors hyperinfected with T. cruzi . An effective translation of Western disease concepts into traditional preventive measures is missing because asymptomatic infections are not generally perceived as threat by the communities. New participatory approaches involving existing ethnomedical knowledge systems could be a successful strategy in the control of T. cruzi infection.

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Summary Globally, more than six million people are infected with Trypanosoma cruzi , the causative protozoan parasite of the vector-borne Chagas disease (CD). We conducted a cross-sectional ethnopharmacological field study in Bolivia among different ethnic groups where CD is hyperendemic. A total of 775 extracts of botanical drugs used in Bolivia in the context of CD and botanical drugs from unrelated indications from the Mediterranean De Materia Medic a compiled by Dioscorides two thousand years ago were profiled in a multidimensional assay uncovering different antichagasic natural product classes. Intriguingly, the phylobioactive anthraquinone hotspot matched the antichagasic activity of Senna chloroclada , the taxon with the strongest ethnomedical consensus for treating CD among the Izoceño-Guaraní. Testing common 9,10-anthracenedione derivatives in T. cruzi cellular infection assays demarcates hydroxyanthraquinone as a potential antichagasic lead scaffold. Our study systematically uncovers in vitro antichagasic phylogenetic hotspots in the plant kingdom as a potential resource for drug discovery based on ethnopharmacological hypotheses.

Globally, more than six million people are infected with Trypanosoma cruzi, the causative protozoan parasite of the vector-borne Chagas disease (CD). In Bolivia, CD is hyperendemic and a major health problem among indigenous communities. Although botanical drugs are used widely among different ethnic groups in Bolivia, studies challenging the hypothesis that effective antitrypanosomal medicinal agents were identified empirically are lacking. We conducted a cross-sectional ethnopharmacological field study in Bolivia among different ethnic groups in the Chaco, Chiquitanía and Inter-Andean valleys. We compared botanical drugs used in Bolivia in the context of CD with botanical drugs from unrelated indications from the Mediterranean De Materia Medica (DMM) compiled by Dioscorides two thousand years ago. A total of 775 ethyl acetate plant extracts with and without ethnomedical indications for CD treatment were profiled against T. cruzi epimastigote and procyclic T. brucei proliferation, parasite release from T. cruzi trypomastigote infected cells, as well as for host cell cytotoxicity in vitro. Inhibition of parasite release was monitored using a flow cytometry-based celluar assay. At 25 µg/mL, less than 5% of all extracts exhibited selective toxicity for T. cruzi. We found no evidence that ethnomedicine-inspired bioprospecting significantly increased the probability of finding selective antichagasic botanical drugs. The ethnomedical data further indicate a discrepancy between local and scientific concepts about CD among the studied ethnic groups. Intriguingly, the phylobioactive anthraquinone hotspot identified in this study matched the antichagasic activity of Senna chloroclada, the taxon with the strongest consensus for treating CD among the Izoceño-Guaraní. Selected antitrypanosomal plant extracts from DMM were subjected to HPLC-based activity profiling and targeted isolation of active compounds yielding sesquiterpene lactones, naphtoquinones and anthraquinones. Because the anthraquinone emodin selectively and potently inhibited T. cruzi in host cell infection, we performed a preliminary structure-activity relationship analysis for the 9,10-anthracenedione scaffold, exploring the impact of differential hydroxylation. This study shows that the multidimensional phylobioactivity-guided identification of antichagasic natural products enables comparative bioprospecting and is suitable to challenge ethnopharmacological hypotheses. Author summaryChagas disease (CD) is a parasitic disease caused by the protozoan Trypanosoma cruzi. In Bolivia, CD is a major health problem among indigenous communities, which frequently use traditional medicine to treat the chronic symptoms of the disease related to cardiomyopathy. However, the ethnomedical context of the use of such remedies is largely unclear and it remains unknown whether the botanical drugs have any effect on parasitemia. In a field study among different ethnic groups in the Chaco, Chiquitanía and Inter-Andean valleys the authors collected ethnobotanical and ethnopharmac...

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