Astronauts also need to be quarantined? What's the logic behind this?

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People who come back from space also need to be quarantined for 14 days? Is there coronavirus in outer space?

Experts say that isolating astronauts is mainly for two purposes.

First, prevent the spread of new infectious diseases.

The air system in the space capsule is a closed loop. Although appropriate purification measures have been taken, the subjective feeling is still inferior to the fresh air in nature. The closed system also provides the possibility for the growth of microorganisms.

In addition, space radiation may also cause genetic mutations in bacteria and viruses. One breeding method is to use the mutagenic effect of space radiation on seeds to screen new varieties with excellent traits, and bacteria and viruses may also mutate under the influence of space radiation. The new bacteria or viruses produced may break through the human immune barrier and cause the occurrence of new infectious diseases. Although this possibility is not great and has not yet occurred, it cannot be ruled out.

Second, consider the astronauts themselves.

From rocket launch to spacecraft return, astronauts will face several challenges.

1) Continuous state of stress.

In order to break free from gravity, rockets need to reach very high flight speeds. In the process of continuous acceleration, astronauts need to bear a large gravitational load. In addition, due to the limitation of the thrust of the space shuttle, the load is limited and the spacecraft cannot be made very large. The limitation of space will produce a certain sense of oppression on the astronauts' psychology, and these factors will put the body in a state of stress.

Under stress, the body's secretion of adrenal glucocorticoids increases, which improves the body's ability to cope with challenges and suppresses the immune system. At this time, symbiotic or latent bacteria and viruses in the body may cause trouble, leading to an increase in infectious diseases such as pharyngitis, colds, and even pneumonia.

2) The impact of microgravity.

Space is a weightless environment. Blood circulation and lymphatic circulation will be affected, and even the morphology of immune cells will change to a certain extent.

3) Radiation from outer space.

Radiation can affect the hematopoietic function of the bone marrow, which is the "cradle" of immune cells. Therefore, radiation may cause damage to bone marrow hematopoietic cells, leading to a decrease in the number of immune cells and a weakening of their function.

In addition, changes in circadian rhythms and reduced exercise can lead to a decline in astronauts' immunity.

Therefore, from the perspective of preventing new species of pathogenic microorganisms and protecting the health of astronauts, the quarantine system for infectious diseases should be referred to and astronauts should be managed under the three-level quarantine system. Then, the quarantine system should be gradually transitioned to the second-level and first-level quarantine systems until the quarantine is lifted.

Author: Tao Ning

Source: China Science and Technology Press