Viral Populations within the International Space Station's Internal Active Thermal Control System Ground Support and Potential Flight Hardware 2007-01-3108

The Internal Active Thermal Control System (IATCS) aboard the International Space Station (ISS) contains an aqueous, alkaline fluid (pH 9.5±0.5) that aids in maintaining a habitable environment for the crew. Because microbes have significant potential to cause disease, adverse effects on astronaut health, and microbe-induced corrosion, the presence of both bacteria and viruses within IATCS fluids is of concern. This study sought to detect and identify viral populations in IATCS samples obtained from the Kennedy Space Center as a first step towards characterizing and understanding potential risks associated with them. Samples were concentrated and viral nucleic acids (NA) extracted providing solutions containing 8.87-22.67 μg NA per mL of heat transfer fluid. After further amplification viral DNA and cDNA were then pooled, fluorescently labeled, and hybridized onto a Combimatrix panvira 12K microarray containing probes for ∼1,000 known human viruses. Positive hybridizations were observed for probes from the Adenoviridae, Mononegavirales, Poxovirade, Orthomyxoviridae, Flaviviridae, Herpesviridae, Papillomaviridae, Parvoviridae, and Reoviridae families. The data generated in this study using both traditional and molecular techniques confirm that viral particles are present within the IATCS. A comprehensive understanding of the microbial ecology of the IATCS and HTF is needed to completely characterize associated risks, and further study is needed to understand the role of viral populations in the overall microbial load.