Biological warfare agents include bacteria, viruses, fungi, and biological toxins. Some agents are frequently lethal while others are intended to cause illness or incapacitation. Biological warfare can be directed not only at the human population but also at crops and livestock. More than 180 pathogens have been researched or employed as biological weapons, including anthrax, tularemia, brucellosis, plague, Legionnaire’s disease, Q fever, glanders, melioidosis, smallpox, viral hemorrhagic fevers, influenza, ricin, botulinum toxin, staphylococcal enterotoxin B, coccidiosis, rice blast, and wheat rust. Biological warfare agents are most likely to be dispersed as aerosols to be more easily spread amongst large populations. However, certain agents can be spread from person to person or by vectors, ingestion, direct contact, or other methods.
In the absence of a declared or witnessed biological attack, early symptoms of biological warfare agents are likely to be nonspecific. Clues to a biological warfare attack include unusually large numbers of patients presenting simultaneously with similar symptoms as well as increased morbidity and mortality as compared to more common illnesses. Other epidemiologic red flags might include significant numbers of patients who live or work in the same area, attended the same event, ate at the same restaurant, etc. Depending on the biological warfare agent involved, person to person transmission may or may not be a concern. The use of agents that are capable of causing severe illness and death may quickly cause healthcare resources to be overwhelmed with patients requiring critical care and life-saving interventions, in addition to what may be a large number of asymptomatic or mildly symptomatic patients who seek medical care. Certain agents can be treated with medications or even avoided with post-exposure immunizations or prophylactic medications, whereas others can only be managed with supportive care. Detection of a biological attack, identification of the agents used, and determining the population at risk are vital to both incident management and patient management.       
The relatively recent use of biological agents such as ricin and anthrax demonstrates how even small-scale biological warfare attacks will quickly become international news. Once a patient has been diagnosed with a disease caused by a biological warfare agent, healthcare providers will be responsible for communicating not only numerous colleagues and staff but also with public health officials, law enforcement agencies, members of the media, and elected officials. In attacks involving numerous numbers of casualties or high-profile targets such as elected officials, the marshaling of resources to respond will almost certainly reach the national level. (Level V)
Important communication points early in the care of the patient among physicians, nurses, and pharmacists will include adequate decontamination of the patient and appropriate precautions for first responders and hospital staff to avoid the spread of contagious diseases or additional casualties. Training and education prior to such an event will be more effective than just-in-time training after an event has occurred when emotions run high and resources may run low. In large-scale events, it will be essential for healthcare staff to have a clear understanding of their available resources as well as the anticipated demands on those resources, and continuously communicating with government officials to access medical supply stockpiles and resources for the capacity to treat large numbers of patients will be vital. (Level V)