What is a Biological Hazards?

A biological hazard or biohazard is an organism, or substance derived from an organism, that poses a threat to (primarily) human health. This can include medical waste or samples of a microorganism, virus or toxin (from a biological source) that can impact human health. It can also include substances harmful to animals. The term and its associated symbol is generally used as a warning, so that those potentially exposed to the substances will know to take precautions. There is also a biohazard HCS/WHMIS logo which utilizes the same symbol.
In Unicode, the biohazard sign is U+2623 (☣).
Biohazardous agents are classified for transportation by UN number:
UN 2814 (Infectious Substance, Affecting Humans)
UN 2900 (Infectious Substance, Affecting Animals)
UN 3373 (Diagnostic Specimen or Clinical Specimen or Biological Substance, Category B)
UN 3291 (Medical Waste

Biological Agent

A biological agent is an infectious disease or toxin that can be used in bioterrorism or biological warfare. There are more than 1200 different kinds of biological agents.
Biological agents include prions, viruses, microorganisms (bacteria and fungi) and some unicellular and multicellular eukaryotes (for example parasites) and their associated toxins. They have the ability to adversely affect human health in a variety of ways, ranging from allergic reactions that are usually relatively mild, to serious medical conditions, even death. These organisms are ubiquitous in the natural environment; they are found in water, soil, plants, and animals. Because many biological agents reproduce rapidly and require minimal resources for preservation, they are a potential danger in a wide variety of occupational settings.

Biosafety Level

A Biosafety Level is the level of the biocontainment precautions required to isolate dangerous biological agents in an enclosed facility. The levels of containment range from the lowest biosafety level 1 to the highest at level 4. In the United States, the Centers for Disease Control and Prevention (CDC) have specified these levels. In the European Union, the same biosafety levels are defined in a directive

Crimean-Congo hemorrhagic fever

Crimean-Congo hemorrhagic fever (CCHF) is a widespread tick-borne viral disease, a zoonosis of domestic animals and wild animals, that may affect humans. The pathogenic virus, especially common in East and West Africa, is a member of the Bunyaviridae family of RNA viruses. Clinical disease is rare in infected mammals, but commonly severe in infected humans, with a 30% mortality rate. Outbreaks of illness are usually attributable to handling infected animals or people.