Prehistoric Pathoecology as Represented by Parasites of a Mummy from the Peruaçu Valley, Brazil

Extracellular Vesicles: Potential Role in Remote Signaling and Inflammation in Trypanosoma cruzi-Triggered Disease

Extracellular vesicles (EVs) act as cell communicators and immune response modulators and may be employed as disease biomarkers and drug delivery systems. In infectious diseases, EVs can be released by the pathogen itself or by the host cells (infected or uninfected), potentially impacting the outcome of the immune response and pathological processes. Chagas disease (CD) is caused by infection by the protozoan Trypanosoma cruzi and is the main cause of heart failure in endemic areas. This illness attracted worldwide attention due to the presence of symptomatic seropositive subjects in North America, Asia, Oceania, and Europe. In the acute phase of infection, nonspecific signs, and symptoms contribute to miss diagnosis and early etiological treatment. In this phase, the immune response is crucial for parasite control; however, parasite persistence, dysregulated immune response, and intrinsic tissue factors may contribute to the pathogenesis of chronic CD. Most seropositive subjects remain in the indeterminate chronic form, and from 30 to 40% of the subjects develop cardiac, digestive, or cardio-digestive manifestations. Identification of EVs containing T. cruzi antigens suggests that these vesicles may target host cells and regulate cellular processes and the immune response by molecular mechanisms that remain to be determined. Parasite-released EVs modulate the host-parasite interplay, stimulate intracellular parasite differentiation and survival, and promote a regulatory cytokine profile in experimental models of CD. EVs derived from the parasite-cell interaction inhibit complement-mediated parasite lysis, allowing evasion. EVs released by T. cruzi-infected cells also regulate surrounding cells, maintaining a proinflammatory profile. After a brief review of the basic features of EVs, the present study focuses on potential participation of T. cruzi-secreted EVs in cell infection and persistence of low-grade parasite load in the chronic phase of infection. We also discuss the role of EVs in shaping the host immune response and in pathogenesis and progression of CD.

Paleoparasitology and pathoecology in Russia: Investigations and perspectives

Russia, both as the USSR and the Russian federation, provided a source of parasitological theory for decades. A key figure in Russian parasitology was Yevgeny Pavlovsky. He developed the nidus concept of Pavlovsky provided the conceptual basis for the field of pathoecology. He also coined the term "Paleoparasitology". Pathoecology is a foundation concept in archaeological parasitology. Paleoparasitology, as defined by Pavlovsky, is an avenue for understanding of host parasite evolution over very long time periods. These contributions are not fully recognized internationally. Similarly, the long history of Russian paleontological and archaeological investigations are not fully known. Most recently, discoveries from archaeological sites show that a pattern of zoonotic infection prevailed among archaeological populations in central Russia. This included a case of apparent host switching of beef tapeworm infection to reindeer. This latter discovery raises the possibility that archaeological parasitology can contribute to the new Stockholm Paradigm of ecological fitting, host switching, and emergent disease. This review covers all of the parasitological discoveries from ancient Russia and illustrates how Russian models and discoveries defined parasitological theory in the past and present.

Reestablishing rigor in archaeological parasitology

Archaeological parasitology originated in the mid-twentieth century with interdisciplinary teams of specialists directed by archaeologists. The goals of such studies were detailed analyses of dietary, medicinal, and environmental factors that shaped the patterns of infection. By the 1970s, a cadre of unique coprolite analysts was trained to analyze macroscopic and microscopic remains for integrated reconstructions of the cultural determinants of parasitism. During these first phases of research, diagnostic rigor was maintained by direct training of specialists in parasitology and archaeology sub-disciplines including archaeobotany and archaeopalynology. Near the end of the twentieth century, however, "paleoparasitology" was defined as a separate field focusing on defining parasite distribution through time and space. Ironically, this focus resulted in an increase in misdiagnosis, especially prominent after 2000. Paleoparasitology does not explicitly include other specialized studies in it research design. Thus, dietary, environmental and medicinal inferences have been neglected or lost as samples were destroyed solely for the purpose of parasitological analysis. Without ancillary archaeological studies, paleoparasitology runs the risk of separation from archaeological context, thereby reducing its value to the archaeologists who recover samples for analysis.

A Case of Ectopic Paragonimiasis in a 17th Century Korean Mummy

Archaeoparasitological studies on fossilized feces obtained from Joseon Dynasty (1392-1910 CE) mummies have provided invaluable data on the patterns of parasitic infection in pre-modern Korean societies. In our recent radiological investigation of a 17th century Joseon mummy discovered in Cheongdo (South Korea), we located a liver mass just below the diaphragm. Anatomical dissection confirmed the presence of a mass of unknown etiology. A subsequent parasitological examination of a sample of the mass revealed a large number of ancient Paragonimus sp. eggs, making the current report the first archaeoparasitological case of liver abscess caused by ectopic paragonimiasis.