Spaceflight Virology: What Do We Know about Viral Threats in the Spaceflight Environment?

Abstract

Viruses constitute a significant part of the human microbiome, so wherever humans go, viruses are brought with them, even on space missions. In this mini review, we focus on the International Space Station (ISS) as the only current human habitat in space that has a diverse range of viral genera that infect microorganisms from bacteria to eukaryotes. Thus, we have reviewed the literature on the physical conditions of space habitats that have an impact on both virus transmissibility and interaction with their host, which include UV radiation, ionizing radiation, humidity, and microgravity. Also, we briefly comment on the practices used on space missions that reduce virus spread, that is, use of antimicrobial surfaces, spacecraft sterilization practices, and air filtration. Finally, we turn our attention to the health threats that viruses pose to space travel. Overall, even though efforts are taken to ensure safe conditions during human space travel, for example, preflight quarantines of astronauts, we reflect on the potential risks humans might be exposed to and how those risks might be aggravated in extraterrestrial habitats.

Host-Associated Phages Disperse across the Extraterrestrial Analogue Antarctica

“…However, the field of astrovirology has so far generally found little attention (75). The contribution of lysogenic and episomal phage ('hidden hitchhikers') to overall viral loads on spacecraft and associated (76)(77)(78), tobacco mosaic virus to survive space flight equivalent proton irradiation (79), the occurrence of phages and human-related circoviruses in clean rooms (80) and inoviruses on the ISS (81,82).…”

Medical Astro-Microbiology: Current Role and Future Challenges

“…A review of our current understanding in spaceflight virology was recently published. 76 So far, at least two studies using culture independent methods have included viruses aboard the ISS. 54 , 77 NASA’s twin study provided a thorough assessment of gut microbiome changes associated with spaceflight capturing both the single-stranded (ss) and double-stranded (ds) DNA virome.…”

Solar Ultraviolet Light Collector for Germicidal Irradiation on the Moon

“…Potential health risks during spaceflights include short-term health consequences from being in microgravity (e.g., nausea, blurred vision), as well as long-term health consequences that arise or continue months or years after a flight (e.g., radiationinduced cancers, loss of bone mass) 22,23 . Astronauts are in a long time microgravity conditions and exposed to compromise of the immune system, determining alteration of the distribution of circulating leukocytes, production of cytokines, the function of Natural Killer and T cells, granulocyte function, levels of immunoglobulins, virus-specific immunity and increased reactivation of latent viruses [24][25][26][27][28][29][30] . Moreover, astronauts are exposed to alteration of the commensal microbial population, reduction of anaerobic microorganism's presence and increase of aerobic Gram-negative bacteria and staphylococci on the skin, upper respiratory tract, and colon [31][32][33][34][35][36] .…”

“…Although an increased risk for the astronauts' health aboard has often been addressed, infections of crew members or health issues related to the pathogenic action of microorganisms have been reported only rarely 45 . Crew members are the primary source of microorganisms, capable of eliminating many particles (potentially carrying biological agents) in the environment both through the desquamation of the skin, through the acts of coughing, sneezing, speaking, breathing, etc., in a context becoming even more complex dealing with microgravity 29,32,[46][47][48][49][50][51] and the impossibility to exchange with primary air. Data obtained from the Apollo 26 , Skylab 52 , space shuttle 38 , and the Russian space station Mir 27,37 confirm that space environments are compatible with human occupation.…”