Sex, Subdivision, and Domestic Dispersal of Trypanosoma cruzi Lineage I in Southern Ecuador

Trypanosoma cruzi is transmitted by blood sucking insects known as triatomines. This protozoan parasite commonly infects wild and domestic mammals in South and Central America. However, triatomines also transmit the parasite to people, and human infection with T. cruzi is known as Chagas disease, a major public health concern in Latin America. Understanding the complex dynamics of parasite spread between wild and domestic environments is essential to design effective control measures to prevent the spread of Chagas disease. Here we describe T. cruzi genetic diversity and population dynamics in southern Ecuador. Our findings indicate that the parasite circulates in two largely independent cycles: one corresponding to the sylvatic environment and one related to the domestic/peridomestic environment. Furthermore, our data indicate that human activity might promote parasite dispersal among communties. This information is the key for the design of control programmes in Southern Ecuador. Finally, we have encountered evidence of a sexual reproductive mode in the domestic T. cruzi population, which constitutes a new and intriguing finding with regards to the biology of this parasite

Membrane Vesicles from the Gut Microbiota and Their Interactions with the Host

Gut microbiota plays an essential role in maintaining intestinal homeostasis and human health. Microbiota establishes a complex network of dynamic and reciprocal interactions with the intestinal epithelium and immune system. The mucin layer that covers the epithelium prevents luminal bacteria from accessing host cells. Thus, microbiota–host communication mainly relies on secreted factors and membrane vesicles (MVs), which can cross the inner mucus layer and reach the epithelium. This chapter focuses on the role of microbiota-secreted MVs as key players in signaling processes in the intestinal mucosa. This is an emerging research topic, with the first reports dating from 2012. Microbiota-derived MVs are involved in interspecies communication in the gut, between bacteria and between microbiota and host. Here we present current knowledge on the mechanisms used by microbiota MVs to assist and control the gut microbial community and to modulate host immune and defense responses. Constant stimulation of immune receptors by microbiota MVs results in tightly controlled inflammation that contributes to tolerogenic responses essential to maintaining intestinal homeostasis. Moreover, gut microbiota MVs are emerging as physical vehicles for distribution and delivery of bacterial effectors to distal tissues in human health and disease