| Abstrakt: |
Simple Summary: Giardiosis, trichomonosis, leishmaniosis, and trypanosomosis are parasitic diseases caused by flagellated protozoa that have a major global health impact, and their control is a priority action line in the agenda of the current One Health Program. The pathogens causing these diseases can establish an endosymbiotic relationship with RNA viruses of the Totiviridae family that can alter the course of the final infection in a mammal. To easily understand the sequence of interactions that occur between the agents involved, from a structural point of view, we can imagine a "matryoshka"-type infection model, wherein the virus represents the smallest matryoshka infecting the flagellated protozoan, which represents the medium matryoshka infecting the mammal, the largest matryoshka. In this manuscript, we will review the available information on the complications generated, such as the aggravation of pathogenesis or treatment failures, because of the established association between these flagellated pathogens and their respective endosymbiont viruses. Accurate diagnosis is required to detect these situations of endosymbiont co-infection and to be able to apply tailor-made treatments that target both the flagellated parasite and the virus that hides inside it. Taken together, these approaches will allow us to achieve and optimize appropriate sanitary control strategies. Three genera of viruses of the family Totiviridae establish endosymbiotic associations with flagellated protozoa responsible for parasitic diseases of great impact in the context of One Health. Giardiavirus, Trichomonasvirus, and Leishmaniavirus infect the protozoa Giardia sp., Trichomonas vaginalis, and Leishmania sp., respectively. In the present work, we review the characteristics of the endosymbiotic relationships established, the advantages, and the consequences caused in mammalian hosts. Among the common characteristics of these double-stranded RNA viruses are that they do not integrate into the host genome, do not follow a lytic cycle, and do not cause cytopathic effects. However, in cases of endosymbiosis between Leishmaniavirus and Leishmania species from the Americas, and between Trichomonasvirus and Trichomonas vaginalis, it seems that it can alter their virulence (degree of pathogenicity). In a mammalian host, due to TLR3 activation of immune cells upon the recognition of viral RNA, uncontrolled inflammatory signaling responses are triggered, increasing pathological damage and the risk of failure of conventional standard treatment. Endosymbiosis with Giardiavirus can cause the loss of intestinal adherence of the protozoan, resulting in a benign disease. The current knowledge about viruses infecting flagellated protozoans is still fragmentary, and more research is required to unravel the intricacies of this three-way relationship. We need to develop early and effective diagnostic methods for further development in the field of translational medicine. Taking advantage of promising biotechnological advances, the aim is to develop ad hoc therapeutic strategies that focus not only on the disease-causing protozoan but also on the virus. [ABSTRACT FROM AUTHOR] |
