The total stress of space flight temporarily interrupts the immune system.
Medical experts have discovered the reactivation of the herpes virus in astronauts already in a multi-day stay in gravity-free orbit. It was about the crews of the space shuttle and the International Space Station.
Although only to a limited extent, it has obvious signs of disease, the rate of reactivation of the virus has increased directly in proportion to the duration of the mission. This can pose a significant health risk on long-haul flights.
The rapid detection of virus activity by NASA in astronauts and the simultaneous search for effective methods of treatment help not only in astronautics, but – especially in saliva analysis – in global medical practice.
Astronauts under scrutiny
"NASA astronauts have to last weeks, even months, for exposure to microgravity and cosmic radiation, not to mention the extreme overhead on launch and return. More family stressors, social separation, confined space and an altered cycle of sleep and wakefulness are added to this physical challenge, "said Satish Mehta, a five-member team leader.
With colleagues at the NASA Space Center in Houston, Texas, and three other institutions, they have long examined samples of astronaut saliva, blood, and urine.
They systematically picked them up before, during and after their space flight. In this research, they focused on the incidence of viruses and viral diseases.
Stress and immunity
"During space flight, the excretion of stress hormones, such as cortisol and adrenaline, increases to the blood, both of which are known to interfere with the functioning of the immune system. the immune system of astronauts, which usually suppress the activity of the virus and remove it from the body, decreases. Sometimes it takes 60 days after the flight, "explained Satish Mehta.
This weakening of immunity gives a chance of inactive viruses hidden in the body. "So far, we have detected the activation of the herpes virus in 47 of the 89 (53 percent) astronauts in the short-range space shuttle and 14 of the 23 (61 percent) in longer ISS missions. or after summer, or in control of suitable healthy individuals on Earth, "he continued.
A palette of herpes varied
Astronaut team members discovered the activity of eight known human herpes viruses. Also variants that cause oral and genital herpes, chickenpox and shingles. They all occur in our cells – including nerve cells – throughout the life of an infected person.
They also found herpes related viruses activated CMV (cytomegalovirus) and EBV (Epstein-Barr virus) in the samples. These are also long term or permanent in the body. Usually without symptoms, but inducing infectious mononucleosis or "kissing disease".
Memento for the future
Even with virus-activated astronauts, this condition has not yet led to an apparent disease in the vast majority. "These symptoms only evolved into six astronauts, and this has led to mild illness," said Satish Mehta.
However, astronauts have become reactivated virus carriers, and people with reduced immunity in their surroundings, especially the sick, but also newborns and the elderly, can become infected. The body fluids of the astronaut contained CMV viruses and shingles 30 days after the return of the ISS.
In addition, the threat of reactivation of the herpes virus increases from the time spent in the space. The selection of long-distance teams will therefore have to accentuate prevention. Ideal vaccination, but this is only possible against virus-shingles.
For other herpes viruses, the development of vaccines is still not very promising. The spacecraft will need to have wide-spectrum antiviral drugs on board. However, targeted treatments for individual viruses also need to be developed.
The study was published by Frontiers in Biology. The report was published by this magazine.