Database of international risk group classifications for Bacteria, Viruses, Fungi, and Parasites. In many countries, including the United States, infectious agents are categorized in risk groups based on their relative risk. Depending on the country and/or organization, this classification system might take the following factors into consideration: Pathogenicity of the organism, Mode of transmission and host range, Availability of effective preventive measures (e.g., vaccines), Availability of effective treatment (e.g., antibiotics), and Other factors