The stress of spaceflight gives viruses a holiday from immune surveillance, putting future deep-space missions in jeopardy
Herpes viruses reactivate in more than half of crew aboard Space Shuttle and International Space Station missions, according to NASA research published in Frontiers in Microbiology. While only a small proportion develop symptoms, virus reactivation rates increase with spaceflight duration and could present a significant health risk on missions to Mars and beyond.
NASA's rapid viral detection systems and ongoing treatment research are beginning to safeguard astronauts - and immunocompromised patients on Earth, too.
Herpes viruses reactivate in immunocompromised astronauts
"NASA astronauts endure weeks or even months exposed to microgravity and cosmic radiation - not to mention the extreme G forces of take-off and re-entry," says senior author Dr. Satish K. Mehta of KBR Wyle at the Johnson Space Center. "This physical challenge is compounded by more familiar stressors like social separation, confinement and an altered sleep-wake cycle."
To study the physiological impact of spaceflight, Mehta and colleagues analyze saliva, blood and urine samples collected from astronauts before, during and after spaceflight.
"During spaceflight there is a rise in secretion of stress hormones like cortisol and adrenaline, which are known to suppress the immune system. In keeping with this, we find that astronaut's immune cells - particularly those that normally suppress and eliminate viruses - become less effective during spaceflight and sometimes for up to 60 days after."
In the midst of this stress-induced amnesty on viral killing, dormant viruses reactivate and resurface.
"To date, 47 out of 89 (53%) astronauts on short space shuttle flights, and 14 out of 23 (61%) on longer ISS missions shed herpes viruses in their saliva or urine samples," reports Mehta. "These frequencies - as well as the quantity - of viral shedding are markedly higher than in samples from before or after flight, or from matched healthy controls."
Overall, four of the eight known human herpes viruses were detected. These include the varieties responsible for oral and genital herpes (HSV), chickenpox and shingles (VZV) - which remain lifelong in our nerve cells - as well as CMV and EBV, which take permanent but uneventful residence in our immune cells during childhood. CMV and EBV, are two viruses associated with causing different strains of mononucleosis or the "kissing disease".
Deep-space exploration could depend on effective prevention and treatment
So far, this viral shedding is typically asymptomatic.
"Only six astronauts developed any symptoms due to viral reactivation," says Mehta. "All were minor."
However, continued virus shedding post flight could endanger immunocompromised or uninfected contacts on Earth, like newborns.
"Infectious VZV and CMV were shed in body fluids up to 30 days following return from the International Space Station."
What's more, as we prepare for human deep-space missions beyond the moon and Mars, the risk that herpes virus reactivation poses to astronauts and their contacts could become more crucial.
"The magnitude, frequency and duration of viral shedding all increase with length of spaceflight."
Developing countermeasures to viral reactivation is essential to the success of these deep-space missions, argues Mehta.
"The ideal countermeasure is vaccination for astronauts - but this is so far available only against VZV."
"Trials of other herpes virus vaccines show little promise, so our present focus is on developing targeted treatment regimens for individuals suffering the consequences of viral reactivation.
"This research has tremendous clinical relevance for patients on Earth too. Already, our spaceflight-developed technologies for rapid viral detection in saliva have been employed in clinics and hospitals around the world."
Please link to the original research article in your reporting: https:/ / www. frontiersin. org/ articles/ 10. 3389/ fmicb. 2019. 00016/ full
Dls95405 on March 16th, 2019 at 15:00 UTC »
It’s not clear that it’s caused by space flight. You can go years without a herpes outbreak then have one when under a lot of stress. Space flight qualifies as stressful.
sonofsuperman1983 on March 16th, 2019 at 13:23 UTC »
Could be a potential treatment option in the future. Latency is a large reason why we can rid the human body of thing like herpes and hiv. If you can activate expresss of all the cells carrying latent hiv whilst simultaneously prevent reinfection of other cells through anti-retrovirals the human immune system would destroy the virus.
They are trying something similar in the UK with a combination of drug induced expression.
mvea on March 16th, 2019 at 12:45 UTC »
The title of the post is a copy and paste from the title, subtitle and first paragraph of the linked academic press release here:
Journal Reference:
Herpes Virus Reactivation in Astronauts During Spaceflight and Its Application on Earth
Bridgette V. Rooney1, Brian E. Crucian2, Duane L. Pierson2, Mark L. Laudenslager3 and Satish K. Mehta4*
Front. Microbiol., 07 February 2019
DOI: https://doi.org/10.3389/fmicb.2019.00016
Link: https://www.frontiersin.org/articles/10.3389/fmicb.2019.00016/full
Abstract
Latent herpes virus reactivation has been demonstrated in astronauts during shuttle (10–16 days) and International Space Station (≥180 days) flights. Following reactivation, viruses are shed in the body fluids of astronauts. Typically, shedding of viral DNA is asymptomatic in astronauts regardless of mission duration; however, in some cases, live/infectious virus was recovered by tissue culture that was associated with atopic-dermatitis or skin lesions during and after spaceflight. Hypothalamic-pituitary-adrenal (HPA) and sympathetic-adrenal-medullary (SAM) axes activation during spaceflight occurs as indicated by increased levels of stress hormones including cortisol, dehydroepiandrosterone, epinephrine, and norepinephrine. These changes, along with a decreased cell mediated immunity, contribute to the reactivation of latent herpes viruses in astronauts. Currently, 47/89 (53%) astronauts from shuttle-flights and 14/23 (61%) astronauts from ISS missions shed one or more herpes viruses in saliva/urine samples. Astronauts shed Epstein–Barr virus (EBV), varicella-zoster virus (VZV), and herpes-simplex-1 (HSV-1) in saliva and cytomegalovirus (CMV) in urine. Larger quantities and increased frequencies for these viruses were found during spaceflight as compared to before or after flight samples and their matched healthy controls. The shedding did not abate during the longer ISS missions, but rather increased in frequency and amplitude. These findings coincided with the immune system dysregulation observed in astronauts from shuttle and ISS missions. VZV shedding increased from 41% in space shuttle to 65% in ISS missions, EBV increased 82 to 96%, and CMV increased 47 to 61%. In addition, VZV/CMV shed ≤30 days after ISS in contrast to shuttle where VZV/CMV shed up to 5 and 3 days after flight respectively. Continued shedding of infectious-virus post-flight may pose a potential risk for crew who may encounter newborn infants, sero-negative adults or any immunocompromised individuals on Earth. Therefore, developing spaceflight countermeasures to prevent viral reactivation is essential. Our spaceflight-developed technologies for saliva collection/rapid viral detection have been extended to include clinical applications including zoster patients, chicken pox, post-herpetic neuralgia, multiple sclerosis, and various neurological disorders. These protocols are employed in various clinics and hospitals including the CDC and Columbia University in New York, as well as overseas in Switzerland and Israel.