Which pathogen is classified in Risk Group 4?

The classification of pathogens into Risk Groups is based on their potential to cause disease in healthy individuals, the severity of the disease, and the availability of preventative or therapeutic measures. Pathogen Risk Group 4 includes agents that pose a high risk of life-threatening disease, are likely to be transmitted via aerosols, and for which there is no effective treatment or preventative measures available.

Ebola virus is classified in Risk Group 4 due to its highly pathogenic nature and the severity of the hemorrhagic fever it causes, which has a high fatality rate. The modes of transmission and the fact that it requires high containment measures for laboratory handling further solidify its classification.

Other pathogens mentioned, such as HIV and Hepatitis B, are classified in lower risk groups because, while they can result in severe illness, effective treatments and preventive strategies are available. Mycobacterium tuberculosis, responsible for tuberculosis, is also classified in a lower risk group since it does have effective treatment options, albeit it can be serious.