Author Topic: Space herpes: dormant viruses reactivate during spaceflight  (Read 2191 times)

Offline sanman

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Spaceflight has been found to reactivate viruses that were previously dormant in the body:

https://www.eurekalert.org/pub_releases/2019-03/f-dva031519.php

Apparently, the immune system becomes impaired under the conditions of spaceflight, which may have implications for long-term travel and habitation in outer space.

What does this mean for the future of humanity in space?

Offline eeergo

I wonder how much of this is due to the journey-like aspects of current spaceflight, and how it correlates with similar settings such as long-dive submarine crews. Anecdotal evidence (i.e. myself and other close acquaintances) points me towards a similar effect when in long work trips, even when in comfortable/hygienic settings, jetlag was been tamed and there's a low stress load. Skin rashes or pimples are more abundant and persistent, hormonal stress levels are noticeable through irregular bodily functions...

Perhaps lack of exposure to sunlight is one of the contributors, beyond circadian rythms? Thinking about pleasure vs business trips...
« Last Edit: 03/17/2019 05:34 am by eeergo »
-DaviD-

Online DrRobin

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Ok, sorry for the click-bait heading but this may be the only time I ever get to post an actual piece of space-related news in my own exact field of professional expertise (I am an Infectious Disease doctor and virologist studying herpes viruses.). This new research manuscript in Frontiers in Microbiology shows significant and persistent reactivation of multiple herpes viruses in astronauts while in space. This is not really a surprising finding, since it has long been known (though the precise molecular mechanisms are not fully understood) that herpes viruses tend to reactivate when the host is under stress. One of the earliest published studies of this was actually in astronauts waiting to go up into space in the Mercury/Gemini era. All the members of the herpesvirus family (Herpes Simplex, Varicella (Chickenpox), Epstein-Barr (Mono), etc.) establish lifelong latency after primary infection and can all reactivate, with the host shedding infectious virus, often unknowingly and without symptoms. This is unlikely to be a very serious issue for now but could be relevant if/when astronauts are in contact with vulnerable people such as those with compromised immune systems or pregnant women without immunity. This week on the NPR comedy news quiz show, "Wait, Wait, Don't Tell Me", they actually picked up on this, making the obvious STD gags (e.g. "Um, Houston? We have a problem. Uh, you might want to get it checked out, too...")[Rooney, et al, "Herpes Virus Reactivation in Astronauts During Spaceflight and Its Application on Earth", Frontiers in Microbiology, 07 February 2019, https://www.frontiersin.org/articles/10.3389/fmicb.2019.00016/full ]

Online DrRobin

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Since this is my field and I did read the actual published research paper, I just want to reassure people that there is less here than meets the eye. Intermittent asymptomatic shedding of herpesviruses is typical of most members of this viral family. Increased herpes viral reactivation when the host is under any kind of stress has been known for a long time. This article is mostly just a cute verification that, surprise, it happens when you stress people out by sending them into space. (The longstanding hypothesis has been that like "rats fleeing a sinking ship", the virus benefits by trying to jump to another host if their current host is tanking.) The effects the authors see are significant in a statistical sense but modest in a clinical sense. That said, as the authors note, it is worth considering this effect if the astronauts could be in contact with vulnerable people, especially since the effect seems to persist for some time after return to Earth. For example, an astronaut returning home to care for a family member with immune suppression due either to illness or chemotherapy might pose an elevated risk to them and (in the case of Herpes Simplex Virus) might lower the threshold where it would make sense to use a suppressive antiviral such as Acyclovir.

Online DrRobin

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As a virologist, I am somewhat skeptical of this genre of research. If you take a very complex system (like the human body) and put it in a novel setting (like zero gravity), all sorts of things are going to change, and it can be very difficult to tease apart what are the actual chains of causation (as opposed to just association). In the particular case of latent herpesviral infection, it has been known for many years that stress on the host increases rates of reactivation. It will be non-trivial to figure out whether there is something specific at work in long-duration spaceflight, or whether it is just another stressor. I certainly think we should be on the lookout for immune-system effects (analogous to the way that effects on visual acuity were not widely predicted), but I think we are a long way from knowing whether spaceflight causes them in some specific way.
« Last Edit: 04/09/2019 07:59 pm by Chris Bergin »

Offline spacenut

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Would artificial gravity help?  Two Starships could dock end to end and slow tumble on the way to Mars for partial gravity.  Also using the Mars near earth synod every 2 years would help shorten the journey.  Would lying under a sunlamp for 15-30 minutes a day help?

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