A biological hazard, or biohazard, is a biological substance that poses a threat to the health of living organisms, primarily humans. This could include a sample of a microorganism, virus or toxin that can adversely affect human health. A biohazard could also be a substance harmful to other animals. A biological hazard is caused by biological waste, such as medical waste, micro organisms, viruses, etc. The biological hazards can affect both human and animal life and health in a variety of ways. Some biohazards have the ability to change DNA structures. The gene mutation that results is one of the biological hazards. Among other diseases that are caused by biological agents, anthrax is one of them. Others are Lassa fever, Glanders, etc.