Symbiosis
In this form of parasitism the organisms are dissimilar, but neither is harmful to the other while the state is beneficial to one or both. Symbiosis will result in one condition becoming conducive to another condition as, for example, presence of certain microörganisms favors the development of tetanus. Germs are sometimes cultivated in symbiosis with other germs. This has been done with the germs that are found in leprosy.