Relationship between Junin virus infection of thymus and the establishment of persistence in rodents

Tolerance has its limits: how the thymus copes with infection

The thymus is required for T cell differentiation; a process that depends on which antigens are encountered by thymocytes, the environment surrounding the differentiating cells, and the thymic architecture. These features are altered by local infection of the thymus and by the inflammatory mediators that accompany systemic infection. Although once believed to be an immune privileged site, it is now known that antimicrobial responses are recruited to the thymus. Resolving infection in the thymus is important because chronic persistence of microbes impairs the differentiation of pathogen-specific T cells and diminishes resistance to infection. Understanding how these mechanisms contribute to disease susceptibility, particularly in infants with developing T cell repertoires, requires further investigation.

Epidemiology of Argentine hemorrhagic fever

Present knowledge points to horizontal transmission as the most significant mechanism for Junín virus maintenance in the main natural reservoirs, namely Calomys musculinus and Calomys laucha. The existence of naturally infected Akodon azarae, both within and outside the endemic area, as well as the finding that other species, ecologically and phylogenetically related to the main reservoirs, such as Akodon molinae and Calomys callidus, can experimentally develop persistent infections with virus shedding through fauces, suggest a potential role for these cricetids as alternative reservoirs. Furthermore, since those rodents inhabit the borders of the area in which Argentine Hemorrhagic fever is endemic, the risk of spread of this area is to be expected. Whether the establishment of Junín virus persistence in Calomys musculinus and other reservoirs depends on viral or host factors, such as a selective defect in L3T4+ lymphocytes as recently shown for mice, remains to be explored.