宿主和寄生物的辩证关系

Dialectic Relationship of Host and Parasite

寄生物（ 包括寄生虫，细菌，真菌，立克次体，病毒等） 虽依赖宿主而生存，却不一定对宿主致病，有的反而对宿主有益。根据达尔文的进化论，“自然选择”要求生物在进化中要不断适应环境。适应是生存最重要的条件，不能适应必将死亡。据此，本文对一些常见的自然因素对于宿主和寄生物两方面进行了初步分析，包括寄生物在宿主体内的繁殖速度，寄生物所引起的宿主的症状，共生现象的出现等。并对晚近发现的朊病毒，发生“星际传染性”的可能性，以及新的传染病的出现等进行了讨论。凡此种种无一不能用辩证唯物论的观点来加以认识。

All Parasites are dependent on their host to live on the world,however it is not necessary that they are harmful to the host,and some parasites are even beneficial.According to the theory of evolution,natural selection demands that all organisms should adapt their environment incessantly in their evolution.Adaptation is the most important condition of life,and non-adaptation will certainly lead to death.The paper makes some preliminary analysis on the influence of some common natural factors on both parasite and host,including reproductive rate of the parasites,the symptoms and signs of the host caused by the parasite,the appearance of symbiosis etc.The recent discovery of the prion,the possibility of the occurrence of “interplanetary in fection”,as well as the emergence of the new infectious diseases are also discussed.All these facts can be recognized and explained with the view of dialectic materialism.