Behind the paper: Chagas prevention and control in an endemic area from the Argentinian Gran Chaco Region: data from 14 years of uninterrupted intervention

In this post, we  speak to the authors of a recent PLOS Neglected Tropical Diseases article, Chagas prevention and control in an endemic area from the Argentinian Gran Chaco Region: Data from 14 years of uninterrupted intervention, about the story behind the research. The paper was written by Diego Weinberg, Maria Florencia Casale, Rosa Graciela Cejas, Rafael Hoyos, María Victoria Periago, Elsa Segura, and Marcelo Claudio Abril.

What led you to decide on this research question?

In Argentina, a national program for the control of the vector transmission of Trypanosoma cruzi, causative agent of Chagas Disease, has been in place since 1962. Despite this, in the beginning of the 21^st century, control of vector transmission was still not achieved. For this reason, in 2005, we started working in rural communities of a highly historically endemic area of the province of Santiago del Estero, located withing the Gran Chaco Region.

Through continuous presence since that time, with a local office located in the nearby city of Añatuya, we aimed to both work with local authorities to sustain surveillance and control of Chagas Disease in the area, and to obtain information and evidence on the vector population infestation and re-infestation dynamics, the factors that influenced the presence or absence of triatomine bugs in a household, and also to work together with the population to understand their needs and tailor a comprehensive approach that would allow an intervention that could be sustained through time.

Could you talk us through how you designed your study? What was important for your team as you created the study team?

This study was designed as a public-private collaboration with local authorities and the affected communities. Originally, it was planned as a project in five communities which included household improvement given that the typical houses in this area provide refuge and a food source for triatomine bugs. The need of house improvements arose from the community itself, with a special focus on a lack of water. For this reason, the improvements made were not only to improve those aspects of the structure of the house and peridomicile that served as refuge for bugs (ie. thatched roofs, cracked walls, animal pens, chicken coops, etc.), but also to improve sanitary aspects such as wells for water storage and improved latrines. The inclusion of these aspects acted as a facilitator and aided in the acceptance of the study by the community.

For this reason, it was important to have a multidisciplinary team that could work not only with the specific scientific and technical knowledge required for the surveillance and control of Chagas Disease, as determined by national guidelines, but also individuals from different fields to work with the social and building aspects of the project. Moreover, for the sustainability of the project, it was also very important to have many of the team members present permanently and locally in the field office; most of this team is from Añatuya.

Image Credit: Fundación Mundo Sano

What challenges did you encounter during your study?

Through the years, there have been many challenges that have been due mainly to climatic conditions and changes in local and provincial authorities. Moreover, given that the work is performed closely with the inhabitants of the different communities, there are also scheduling conflicts and other priorities that need to be taken into consideration. Many of the inhabitants work in other areas for long periods of time or are away from their household through most of the day; this sometimes conflicted with certain surveillance and control activities. Additionally, most of the families have domestic animals for subsistence farming and a lot of work had to do with improving animal pens, educating the family to avoid the entrance of dogs, chickens or other animals inside the house, and organization of the peridomicile to minimize the re-infestation of households with triatomine bugs.  

What did you find most striking about your results? How will this research be used?

The low re-infestation indexes of triatome bugs inside the household was a great achievement in the study area, which was maintained through time. The re-infestation indexes in the peridomicile fluctuated, as expected, due to the environmental pressure, the presence of food source for sylvatic triatomines, and in some specific communities, it was due to specific changes that were occurring at the time, such as building of new households, deforestation, and transport or accumulation of firewood, etc. Nonetheless, the work in the peridomicile, with improvement in the management of animals and general organization, allowed for the activity of surveillance and control to be more effective.

We hope the results of this study, using an ecohealth approach with community engagement, can serve as evidence for the implementation of improved surveillance and control activities in other areas with similar conditions, both in Argentina and in other countries of the region. Additionally, the reduction in the triatomine intradomicile infestation achieved in these communities, minimizes the risk of re-infection, and allows advancing in diagnosis and treatment of Chagas Disease.

Figure 5

What further research questions need to be addressed in this area?

This study focused on the aspects of infestation that have to do with the domestic cycle of T. cruzi and the household structure, but there are still environmental factors, such as land use or climatic variables that need to be explored. Moreover, given the zoonotic nature of this disease, further questions that we want to explore have to do with the sylvatic cycle of the disease, ie., the animals that act as reservoirs in the area or the ecotopes where the triatomine bugs live.

Why did you choose PLOS Neglected Tropical Diseases as a venue for your article?

The scope and impact factor of this journal makes it very attractive for this type of work that has to do with a Neglected Tropical Disease such as Chagas. Moreover, in the field of the Neglected Tropical Diseases, it´s an open access journal that is very popular among the researchers in the field and therefore a good platform to make the evidence readily available.