Molecular detection and parasite load of Trypanosoma cruzi in digestive tract tissue of Chagas disease patients affected by megacolon.

Chagas disease, caused by the Trypanosoma cruzi parasite in the Americas affects ∼ 7 million people, 30% with cardiac tissue damage and 10-15% with digestive disorders. In this study, we have developed a protocol to detect the presence of the parasite and estimate its load in resected dysfunctional tissue segments of chronically infected patients with digestive megacolon. We have included samples from 43 individuals, 38/5 with positive/negative serology for Chagas disease and digestive syndromes. Samples of 1.5 to 2.0 cm2 were taken from different points of the dysfunctional digestive tract in specialized centres in Cochabamba, Bolivia. T. cruzi cultures were performed by inoculation with NNN-LIT culture medium, and genomic material was obtained from the samples for multiplex qPCR with TaqMan probes targeting satellite nuclear DNA. Cultures failed to isolate T. cruzi but qPCR reached a sensitivity of 42.1% (16/38) with all three spots and in triplicate. A new quantification methodology using synthetic satellite DNA as quantitation standard revealed parasite loads ranging from 2.2 × 102 to 1.0 × 106 satellite DNA copies/µl. Positive samples from the distal end showed a higher parasite load. The results of the present study strengthen and add further evidence to previous findings in an experimental mouse model of chronic T. cruzi infection, providing a valuable tool to improve scientific knowledge on the relevance of the digestive tract in parasite persistence, and underline the need of a better understanding of host-pathogen interaction in digestive tissues, considering pathophysiology, disease immunology and response to treatment.

Community-based entomological surveillance in three Chagas disease-endemic regions in sub-Andean Bolivia.

BACKGROUND: Chagas disease is endemic throughout most of Bolivia, with prevalence rates of 25% observed in some geographic areas located mainly in the sub-Andean region. METHODS: Community-based entomological surveillance was carried out in the sub-Andean departments of Cochabamba (municipalities of Cochabamba, Punata and Sacaba), Tarija (municipality of Tarija) and Chuquisaca (municipality of Sucre). The surveillance parameters evaluated were: (i) the proportion of cards with the presence of triatomines; (ii) the distribution of positive cards by area; and (iii) the proportion of cards with the presence of infected triatomines. RESULTS: Of the cards returned, in 852 (3.1%) there was a mention of the presence of triatomines. The species Triatoma infestans, Triatoma sordida and Triatoma guasayana were identified in 812 (95.3%), 39 (4.6%) and 1 (0.1%), respectively. The median monthly positivity rate of the cards during 2011-2018 was higher in Punata (9.1%; IQR=3.2-15.4%). The median monthly rate was highest in 2012 (2.7%; IQR=0-5.6%). Fifty positive cards (5.8%) presented insects that were positive for trypanosomatids, mainly in Cochabamba and Punata. CONCLUSIONS: The report of triatomines foci by inhabitants represents an effective surveillance system coordinated by a network of specialized and multidisciplinary health centers. These strategies, which should be included in the health policies of endemic countries, enable extending and deepening the dialogue among technicians, communities and their local authorities.

Entomological surveillance with community engagement at Chagas Platform Centers for comprehensive care in the mesothermal valleys of three regions of the endemic area of Triatoma infestans in Bolivia

Background: The detection of residual foci inside the houses, or the reinfestation of triatomines is one of the main entomological surveillance challenges. Actions aimed at increasing the probability of vector detection and to detect re-infestation when the density of vector populations is low, is a priority objective for Chagas control programs. Methods: Families belonging to local communities were responsible of triatomine specimens capture, following a strategic methodology based on entomological surveillance with community participation developed by the National Chagas Programme of the Ministry of Health of Bolivia. The main objective of the study is to evaluate the entomological surveillance strategy with community engagement implemented in Chagas Platform Centers for comprehensive care (CPs). The degree of intradomicillary residual vector infestation, the main seasonal period of triatomines capture, and natural infection by trypanosomatids rates were evaluated. Results: In rural and peri-urban Punata, in the Department of Cochabamba, the houses infestation rate by triatomines exceeds the national average and is above the recommendations of PAHO / WHO. The observations during the seasons of the year showed that Spring season (September to December) was the period where there was a higher average of T. infestans positive houses detected by the families participating in the study in the three departments of Bolivia. The presence of infected triatomines with Trypanosomatideos in positive houses was 6% in the study area, still finding active domestic cycles in rural and peri-urban areas and not in urban areas where triatomines with parasites were not reported during the seven years of monitoring. Conclusions: Reporting infestation foci by the inhabitants is the simplest and most direct way of participation of the community in entomological surveillance. These strategies should be included in the health policies of the countries, as well as extending and deepening the dialogue between technicians, communities and their local authorities.

A strategy for scaling up access to comprehensive care in adults with Chagas disease in endemic countries: The Bolivian Chagas Platform.

BACKGROUND: Bolivia has the highest prevalence of Chagas disease (CD) in the world (6.1%), with more than 607,186 people with Trypanosoma cruzi infection, most of them adults. In Bolivia CD has been declared a national priority. In 2009, the Chagas National Program (ChNP) had neither a protocol nor a clear directive for diagnosis and treatment of adults. Although programs had been implemented for congenital transmission and for acute cases, adults remained uncovered. Moreover, health professionals were not aware of treatment recommendations aimed at this population, and research on CD was limited; it was difficult to increase awareness of the disease, understand the challenges it presented, and adapt strategies to cope with it. Simultaneously, migratory flows that led Bolivian patients with CD to Spain and other European countries forced medical staff to look for solutions to an emerging problem. INTERVENTION: In this context, thanks to a Spanish international cooperation collaboration, the Bolivian platform for the comprehensive care of adults with CD was created in 2009. Based on the establishment of a vertical care system under the umbrella of ChNP general guidelines, six centres specialized in CD management were established in different epidemiological contexts. A common database, standardized clinical forms, a and a protocolized attention to adults patients, together with training activities for health professionals were essential for the model success. With the collaboration and knowledge transfer activities between endemic and non-endemic countries, the platform aims to provide care, train health professionals, and create the basis for a future expansion to the National Health System of a proven model of care for adults with CD. RESULTS: From 2010 to 2015, a total of 26,227 patients were attended by the Platform, 69% (18,316) were diagnosed with T. cruzi, 8,567 initiated anti-parasitic treatment, more than 1,616 health professionals were trained, and more than ten research projects developed. The project helped to increase the number of adults with CD diagnosed and treated, produce evidence-based clinical practice guidelines, and bring about changes in policy that will increase access to comprehensive care among adults with CD. The ChNP is now studying the Platform's health care model to adapt and implement it nationwide. CONCLUSIONS: This strategy provides a solution to unmet demands in the care of patients with CD, improving access to diagnosis and treatment. Further scaling up of diagnosis and treatment will be based on the expansion of the model of care to the NHS structures. Its sustainability will be ensured as it will build on existing local resources in Bolivia. Still human trained resources are scarce and the high staff turnover in Bolivia is a limitation of the model. Nevertheless, in a preliminary two-years-experience of scaling up this model, this limitations have been locally solved together with the health local authorities.