Making Sense of Chagas Disease among Mexican Immigrants in California.

Mexican immigrants are affected by Chagas disease (CD) in California. It is through the representation of Chagas as a rare disease that participants make sense of the disease. A positive diagnosis has meant the disruption of patients' sense of normality and self-image, as well as their memories of homeland both reproducing and challenging hegemonic and stigmatized ideas of the disease associated with rurality and poverty. Access to treatment and medical care was the major coping mechanism. Health programs on CD should consider the emotional and social impact of the disease on people's self-perceptions to develop better medical care and prevention.

Social Representations and Practices Towards Triatomines and Chagas Disease in Calakmul, México.

Vector-borne transmission of Trypanosoma cruzi (VBTTc) is dependent on the concomitant interaction between biological and environmental hazard over the entire landscape, and human vulnerability. Representations and practices of health-disease-care-seeking and territorial appropriation and use were analyzed for VBTTc in a qualitative ethnographic study in the Zoh-Laguna landscape, Campeche, Mexico. In-depth interviews and participatory observation explored representations and practices regarding ethno-ecological knowledge related to vector-transmission, health-disease-care-seeking, and land use processes. The population has a broad knowledge of biting insects, which they believe are all most abundant in the rainy season; the community´s proximity to natural areas is perceived as a barrier to control their abundance. Triatomines are mostly recognized by men, who have detailed knowledge regarding their occurrence and association with mammals in non-domestic fragments, where they report being bitten. Women emphasize the dermal consequences of triatomine bites, but have little knowledge about the disease. Triatomine bites and the chinchoma are "normalized" events which are treated using home remedies, if at all. The neglected condition of Chagas disease in Mexican public health policies, livelihoods which are dependent on primary production, and gender-related knowledge (or lack thereof) are structural circumstances which influence the environment and inhabitants´ living conditions; in turn, these trigger triatomine-human contact. The most important landscape practices producing vulnerability are the activities and mobility within and between landscape fragments causing greater exposure of inhabitants primarily in the dry season. A landscape approach to understanding vulnerability components of VBTTc from health-disease-care-seeking perspectives and based on territorial appropriation and use, is essential where there is continuous movement of vectors between and within all habitats. An understanding of the structural factors which motivate the population´s perceptions, beliefs, and practices and which create and maintain vulnerability is essential to develop culturally relevant and sustainable community-based VBTTc prevention and control.

Landscape ecology of Trypanosoma cruzi in the southern Yucatan Peninsula.

Landscape interactions of Trypanosoma cruzi (Tc) with Triatoma dimidiata (Td) depend on the presence and relative abundance of mammal hosts. This study analyzed a landscape adjacent to the Calakmul Biosphere Reserve, composed of conserved areas, crop and farming areas, and the human community of Zoh Laguna with reported Chagas disease cases. Sylvatic mammals of the Chiroptera, Rodentia, and Marsupialia orders were captured, and livestock and pets were sampled along with T. dimidiata in all habitats. Infection by T. cruzi was analyzed using mtDNA markers, while lineage and DTU was analyzed using the mini-exon. 303 sylvatic specimens were collected, corresponding to 19 species during the rainy season and 114 specimens of 18 species during dry season. Five bats Artibeus jamaicensis, Artibeus lituratus, Sturnira lilium, Sturnira ludovici, Dermanura phaeotis (Dp) and one rodent Heteromys gaumeri were collected in the three habitats. All but Dp, and including Carollia brevicauda and Myotis keaysi, were infected with predominately TcI in the sylvatic habitat and TcII in the ecotone. Sigmodon hispidus was the rodent with the highest prevalence of infection by T. cruzi I and II in ecotone and domestic habitats. Didelphis viginiana was infected only with TcI in both domestic and sylvatic habitats; the only two genotyped human cases were TcII. Two main clades of T. cruzi, lineages I (DTU Ia) and II (DTU VI), were found to be sympatric (all habitats and seasons) in the Zoh-Laguna landscape, suggesting that no species-specific interactions occur between the parasite and any mammal host, in any habitat. We have also found mixed infections of the two principal T. cruzi clades in individuals across modified habitats, particularly in livestock and pets, and in both haplogroups of T. dimidiata. Results are contradictory to the dilution hypothesis, although we did find that most resilient species had an important role as T. cruzi hosts. Our study detected some complex trends in parasite transmission related to lineage sorting within the matrix. Intriguingly, TcIa is dominant in terrestrial small wildlife in the sylvatic habitat and is the only parasite DTU found in D. virginiana in the domestic habitat, although its frequency remained constant in sylvatic and ecotone vectors. Bats have a key role in TcVI dispersal from the sylvatic habitat, while dogs, sheep, and humans are drivers of TcVI between domestic and ecotone habitats. Overall, our results allow us to conclude that T. cruzi transmission is dependent on host availability within a highly permeable landscape in Zoh Laguna.

[Human vulnerability to Trypanosoma cruzi vector transmission through health-disease processes and social appropriation of the territory]. / La vulnerabilidad humana a la transmisión vectorial de Trypanosoma cruzi a través de los procesos de salud-enfermedad y la apropiación social del territorio.

Risk studies of Trypanosoma cruzi vector transmission have classically overlooked the role of social behaviors and subjectivities within the natural landscape and social environment. A review and analysis of the literature on relevant biological, eco-epidemiological and sociocultural factors was combined with an ethnographic study in order to develop a risk model framework identifying the components of hazard and human vulnerability. Social practices, representations and knowledge regarding the health-disease-care process and the social appropriation of the territory are considered as elements explicative of human vulnerability. Exploring these components within an ethnographic analysis allows new options and more adequate prevention or comprehensive risk control measures to be identified.

La vulnerabilidad humana a la transmisión vectorial de Trypanosoma cruzi a través de los procesos de salud-enfermedad y la apropiación social del territorio / Human vulnerability to Trypanosoma cruzi vector transmission through health-disease processes and social appropriation of the territory

Los estudios sobre el riesgo de la transmisión vectorial de Trypanosoma cruzi a población humana han desatendido el rol del comportamiento y de la subjetividad de las relaciones sociales en el marco del paisaje natural y el contexto social. A través de una revisión y síntesis de la bibliografía sobre los factores biológicos, ecoepidemiológicos y socioculturales que intervienen en el fenómeno, en conjunto con un estudio etnográfico, se propone un modelo de análisis del riesgo que distingue los componentes de peligro y de la vulnerabilidad humana. Los conocimientos, prácticas y representaciones sociales respecto del proceso salud-enfermedad-atención y de la apropiación social del territorio se plantean como elementos explicativos de la vulnerabilidad humana. Los componentes de la vulnerabilidad propuestos se exploran en el marco de un análisis etnográfico, que permite identificar opciones y medidas preventivas o de control integral del riesgo más adecuadas.(AU)

Risk studies of Trypanosoma cruzi vector transmission have classically overlooked the role of social behaviors and subjectivities within the natural landscape and social environment. A review and analysis of the literature on relevant biological, eco-epidemiological and sociocultural factors was combined with an ethnographic study in order to develop a risk model framework identifying the components of hazard and human vulnerability. Social practices, representations and knowledge regarding the health-disease-care process and the social appropriation of the territory are considered as elements explicative of human vulnerability. Exploring these components within an ethnographic analysis allows new options and more adequate prevention or comprehensive risk control measures to be identified.(AU)

La vulnerabilidad humana a la transmisión vectorial de Trypanosoma cruzi a través de los procesos de salud-enfermedad y la apropiación social del territorio / Human vulnerability to Trypanosoma cruzi vector transmission through health-disease processes and social appropriation of the territory

Los estudios sobre el riesgo de la transmisión vectorial de Trypanosoma cruzi a población humana han desatendido el rol del comportamiento y de la subjetividad de las relaciones sociales en el marco del paisaje natural y el contexto social. A través de una revisión y síntesis de la bibliografía sobre los factores biológicos, ecoepidemiológicos y socioculturales que intervienen en el fenómeno, en conjunto con un estudio etnográfico, se propone un modelo de análisis del riesgo que distingue los componentes de peligro y de la vulnerabilidad humana. Los conocimientos, prácticas y representaciones sociales respecto del proceso salud-enfermedad-atención y de la apropiación social del territorio se plantean como elementos explicativos de la vulnerabilidad humana. Los componentes de la vulnerabilidad propuestos se exploran en el marco de un análisis etnográfico, que permite identificar opciones y medidas preventivas o de control integral del riesgo más adecuadas.

Risk studies of Trypanosoma cruzi vector transmission have classically overlooked the role of social behaviors and subjectivities within the natural landscape and social environment. A review and analysis of the literature on relevant biological, eco-epidemiological and sociocultural factors was combined with an ethnographic study in order to develop a risk model framework identifying the components of hazard and human vulnerability. Social practices, representations and knowledge regarding the health-disease-care process and the social appropriation of the territory are considered as elements explicative of human vulnerability. Exploring these components within an ethnographic analysis allows new options and more adequate prevention or comprehensive risk control measures to be identified.