Reactivation of latent human intracellular infections during a months-long expedition at the Antarctic Vostok station.

The complex of spaceflight factors has a significant impact on the immunity functional activity. This influence is probably caused by factors such as isolation, monotony, physical inactivity, sensory deprivation, and increased psycho-emotional tension. Long-term wintering at polar stations can be the ground-based model that is most similar to space flight conditions. This research focused on examining the reactivation of latent human pathogens among 11 participants of the 64th Russian Antarctic expedition to Vostok station. Plasma, saliva and urine samples collected before arriving at the station and also during the wintering were studied. Even at the pre-expedition period, DNA of at least one of the studied pathogens was detected in the saliva and plasma of 10 out of 11 (90%) expedition members. During the wintering all the participants showed changes in the Epstein-Barr virus DNA concentration in body fluids. Moreover, 9 out of 11 (80%) participants showed the human herpes virus type 6 shedding in the saliva and/or plasma. Herpes simplex virus types 1 and 2 shedding was observed in 18% of subjects as well. Additionally, there was an assumption made about the relationship between dynamics of latent pathogen shedding, geomagnetic activity, and the psychological state of expedition participants.