Stress, spaceflight, and latent herpes virus reactivation

Abstract

The effect of stress on immune responses associated with manned space missions is unknown, but concern of diminished immunity on long missions is problematic. Decreased cellular immunity has been reported in astronauts flying on short- and long-duration missions, but the medical significance is unclear as illnesses in astronauts during spaceflights are uncommon. Opportunistic pathogens such as latent viruses pose a unique hazard to crewmembers because of the ineffectiveness of preflight quarantine periods and decreased immune function. Our research has demonstrated that reactivation of latent herpes viruses serves as a surrogate marker for decreased immunity in astronauts. This chapter provides concrete and most recent evidence that spaceflight results in asymptomatic reactivation of latent herpes viruses, during short- and long-duration space missions to the International Space Station. Furthermore, these changes are believed to result from neuroendocrine and immune changes associated with stressors to which the crew is exposed during spaceflight.