Warmflash David, Larios-Sanz Maia, Jones Jeffrey, Fox George E, McKay David S
Department of Biology and Biochemistry, University of Houston, TX, USA.
Aviat Space Environ Med. 2007 Apr;78(4 Suppl):A79-88.
Exploration Class missions to Mars will require precautions against potential contamination by any native microorganisms that may be incidentally pathogenic to humans. While the results of NASA's Viking biology experiments of the 1970s have been generally interpreted as inconclusive for surface organisms, and attributed to active but nonbiological chemistries, the possibility of native surface life has never been ruled out completely. It is possible that, prior to the first human landing on Mars, robotic craft and sample return missions will provide enough data to know with certainty whether future human landing sites harbor extant life forms. If native life were found to exist, it would be problematic to determine whether any of its species might present a medical danger to astronauts. Therefore, it will become necessary to assess empirically the risk that the planet contains pathogens based on terrestrial examples of pathogenicity and to take a reasonably cautious approach to biohazard protection. A survey of terrestrial pathogens was conducted with special emphasis on those whose evolution has not depended on the presence of animal hosts. The history of the development and implementation of Apollo anti-contamination protocol and recommendations of the National Research Council's Space Studies Board regarding Mars were reviewed. Organisms can emerge in Nature in the absence of indigenous animal hosts and both infectious and non-infectious human pathogens are therefore theoretically possible on Mars. Although remote, the prospect of Martian surface life, together with the existence of a diversity of routes by which pathogenicity has emerged on Earth, suggests that the probability of human pathogens on Mars, while low, is not zero. Still, since the discovery and study of Martian life can have long-term benefits for humanity, the risk that Martian life might include pathogens should not be an obstacle to human exploration. As a precaution, it is recommended that EVA (extravehicular activity) suits be decontaminated when astronauts enter surface habitats upon returning from field activity and that biosafety protocols approximating laboratory BSL 2 be developed for astronauts working in laboratories on the Martian surface. Quarantine of astronauts and Martian materials arriving on Earth should also be part of a human mission to Mars, and this and the surface biosafety program should be integral to human expeditions from the earliest stages of the mission planning.
前往火星的探索级任务需要采取预防措施，防止任何可能对人类具有偶发性致病性的本地微生物造成潜在污染。虽然美国国家航空航天局（NASA）20世纪70年代的海盗号生物学实验结果通常被解释为关于火星表面生物的结论不明确，并归因于活跃但非生物的化学反应，但火星表面存在本地生命的可能性从未被完全排除。在人类首次登陆火星之前，机器人航天器和样本返回任务有可能提供足够的数据，以确定未来人类登陆地点是否存在现存生命形式。如果发现存在本地生命，要确定其任何物种是否会对宇航员构成医疗危险将是个难题。因此，有必要根据地球上的致病性实例，凭经验评估火星上存在病原体的风险，并采取合理谨慎的生物危害防护措施。开展了一项对地球病原体的调查，特别关注那些进化不依赖于动物宿主存在的病原体。回顾了阿波罗反污染协议的制定和实施历史以及美国国家研究委员会空间研究委员会关于火星的建议。在没有本土动物宿主的情况下，自然界中也可能出现生物，因此从理论上讲，火星上可能存在传染性和非传染性的人类病原体。尽管可能性很小，但火星表面存在生命的前景，以及地球上出现致病性的多种途径的存在，表明火星上存在人类病原体的概率虽然很低，但并非为零。不过，由于发现和研究火星生命可能对人类有长期益处，火星生命可能包括病原体的风险不应成为人类探索的障碍。作为预防措施，建议宇航员从野外活动返回进入表面栖息地时，对舱外活动（EVA）航天服进行消毒，并为在火星表面实验室工作的宇航员制定近似于实验室生物安全2级的生物安全协议。对抵达地球的宇航员和火星材料进行检疫也应成为人类火星任务的一部分，并且这一点以及表面生物安全计划应从任务规划的最早阶段起就成为人类探险的组成部分。
