Leukemia is not contagious when the finger is pricked by a needle used for leukemia; leukemia is not a contagious disease. The causes of leukemia are mainly related to viruses, radiation, chemical factors, and genetic factors. 1. Virus: such as C-type RNA virus has a close relationship with the occurrence of human T-cell leukemia and lymphoma. 2. Radiation: such as nuclear workers and medical radiation workers continue to work in small doses of radiation environment for a long time, may induce leukemia. 3. Chemical factors: certain chemicals in the environment are closely related to leukemia, such as benzene, smoking, alcohol, hair dyes, etc. In addition, certain drugs, such as ethylenediamine, chloramphenicol, pau d’arco, etc., may increase the incidence of leukemia. 4. Genetic factors: Although leukemia is not a hereditary disease, it can be found in high-risk families, which may be related to living in the same environment. Leukemia should be diagnosed and treated under the guidance of a doctor, not blindly guessed.