What type of pathogens are classified under BSL-4 safety level?

The classification of pathogens under Biosafety Level 4 (BSL-4) pertains to those that pose a significant risk to public health due to their high infectivity and the potential for aerosol transmission. BSL-4 laboratories are equipped to handle these highly infectious agents that can cause severe or fatal diseases in humans, often with no known treatment or vaccine available. The primary focus of BSL-4 is on pathogens that are not only highly infectious but also can spread through airborne routes, meaning that even a small number of organisms can potentially lead to infection if inhaled.

Moreover, BSL-4 facilities are designed with stringent containment measures, including specialized ventilation systems and full-body, air-supplied suits, to protect laboratory personnel from exposure. This level of security is necessary due to the severe consequences of accidentally contracting or releasing such pathogens, emphasizing the importance of rigorous safety protocols in handling them.

In contrast, the other classifications of pathogens, such as low-risk ones, moderately infectious agents, or those that do not affect humans, are managed under lower biosafety levels. These do not require the extensive safety precautions necessary for BSL-4, underscoring the unique dangers posed by the pathogens classified within this highest biosafety category.