Inequalities in the social determinants of health and Chagas disease transmission risk in indigenous and creole households in the Argentine Chaco

Abstract

Background: The social determinants of health (SDHs) condition disease distribution and the ways they are handled. Socioeconomic inequalities are closely linked to the occurrence of neglected tropical diseases, but empirical support is limited in the case of Chagas disease, caused by the protozoan Trypanosoma cruzi. Herein we assessed the relationship between key structural SDHs and the risk of T. cruzi vector-borne transmission in rural communities of the Argentine Chaco occupied by creoles and an indigenous group (Qom). We used multiple correspondence analysis to quantify the household-level socioeconomic position (social vulnerability and assets indices), access to health and sanitation services, and domestic host availability. We identified the most vulnerable population subgroups by comparing their demographic profiles, mobility patterns and distribution of these summary indices, then assessed their spatial correlation and household-level effects on vector domiciliary indices as transmission risk surrogates. Results: Qom households had higher social vulnerability and fewer assets than creoles, as did local movers and migrant households compared with non-movers. We found significantly positive effects of social vulnerability and domestic host availability on infected Triatoma infestans abundance, after adjusting for ethnicity. Access to health and sanitation services had no effect on transmission risk. Only social vulnerability displayed significant global spatial autocorrelation up to 1 km. A hotspot of infected vectors overlapped with an aggregation of most vulnerable households. Conclusions: This synthetic approach to assess socioeconomic related inequalities in transmission risk provides key information to guide targeted vector control actions, case detection and treatment of Chagas disease, towards sustainability of interventions and greater reduction of health inequalities.

Urbanisation, risk stratification and house infestation with a major vector of Chagas disease in an endemic municipality of the Argentine Chaco

“…Recently, a multivariate index of social vulnerability identified households at higher risk of T. cruzi transmission in indigenous communities of the Argentine Chaco [30]. The risk index, herein implemented in urban and periurban settings, derived from the fact that householder detection of triatomines in domestic premises performed better than other methods in multiple rural locations, especially at low triatomine densities [29,40].…”

“…Similarly, in urban and peri-urban communities, the presence of guinea pigs or chickens, the number of human residents per room and building materials were all positively associated with house infestation with T. infestans [9,10,22,23]. Migration and settlement features also affect house infestation and parasite transmission in peri-urban and rural environments [22,24,29,30]. To our knowledge, a detailed analysis of house infestation patterns across the urban-to-rural gradient of a Chagas disease-endemic district has not been performed yet, nor have its determinants been assessed comparatively.…”

Human Trypanosoma cruzi infection is driven by eco-social interactions in rural communities of the Argentine Chaco

“…The population in the area monotonically increased from 2,392 people and 407 inhabited houses in 2008 to 2,548 people and 587 houses in 2015 [54]. The population was composed of two ethnic groups; 93.1% of the residents self-identified as Qom people and the remaining minority as creoles [54]. A household was defined as all the people who occupy a housing unit, including related and nonrelated family members [57].…”

“…As part of a broader research and control program on the transmission of T . cruzi in rural communities of the Argentine Chaco [16,33,41,42,49–53], previous studies have found a strong association between vector indices and social determinants [33,41,54]. In one of these studies, we constructed a social vulnerability index using multiple correspondence analysis (MCA) to synthesize the multiple dimensions of poverty–a method that has been widely used for this purpose in low and middle income countries [55]–and a domestic host availability index (a key ecological factor); both indices were positively associated with the abundance of infected domiciliary T .…”

“…In one of these studies, we constructed a social vulnerability index using multiple correspondence analysis (MCA) to synthesize the multiple dimensions of poverty–a method that has been widely used for this purpose in low and middle income countries [55]–and a domestic host availability index (a key ecological factor); both indices were positively associated with the abundance of infected domiciliary T . infestans [54]. Herein, we focus on human T .…”