NIAID’s pathogen priority list is periodically reviewed and is subject to revision in conjunction with our federal partners, including the Department of Homeland Security, which determines threat assessments, and the Centers for Disease Control and Prevention (CDC), which is responsible for responding to emerging pathogen threats in the United States.
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Category A Priority Pathogens
Category A pathogens are those organisms/biological agents that pose the highest risk to national security and public health because they
- Can be easily disseminated or transmitted from person to person
- Result in high mortality rates and have the potential for major public health impact
- Might cause public panic and social disruption
- Require special action for public health preparedness
Category A Priority Pathogens
Category B Priority Pathogens
Category B pathogens are the second highest priority organisms/biological agents. They
- Are moderately easy to disseminate
- Result in moderate morbidity rates and low mortality rates
- Require specific enhancements for diagnostic capacity and enhanced disease surveillance
Category B Priority Pathogens
- Burkholderia pseudomallei
- Coxiella burnetii (Q fever)
- Brucella species (brucellosis)
- Burkholderia mallei (glanders)
- Chlamydia psittaci (Psittacosis)
- Ricin toxin (from Ricinus communis)
- Epsilon toxin of Clostridium perfringens
- Staphylococcus enterotoxin B
- Typhus fever (Rickettsia prowazekii)
- Food- and Waterborne Pathogens
- Bacteria
- Viruses (Caliciviruses, Hepatitis A)
- Protozoa
- Cryptosporidium parvum
- Cyclospora cayatanensis
- Giardia lamblia
- Entamoeba histolytica
- Toxoplasma
- Fungi
- Additional viral encephalitides
- West Nile Virus
- LaCrosse
- California encephalitis
- Venezuelan equine encephalitis
- Eastern equine encephalitis
- Western equine encephalitis
- Japanese Encephalitis Virus
- Kyasanur Forest Virus
Category C Priority Pathogens
Category C pathogens are the third highest priority and include emerging pathogens that could be engineered for mass dissemination in the future because of
- Availability
- Ease of production and dissemination
- Potential for high morbidity and mortality rates and major health impact
Category C Priority Pathogens
- Emerging infectious disease threats such as Nipah virus and additional hantaviruses
- Tickborne hemorrhagic fever viruses
- Crimean-Congo Hemorrhagic fever virus
- Tickborne encephalitis viruses
- Yellow fever
- Tuberculosis, including drug-resistant TB
- Influenza
- Other Rickettsias
- Rabies
- Prions
- Chikungunya virus
- Severe acute respiratory syndrome associated coronavirus (SARS-CoV)
- Antimicrobial resistance, excluding research on sexually transmitted organisms*
- Research on mechanisms of antimicrobial resistance
- Studies of the emergence and/or spread of antimicrobial resistance genes within pathogen populations
- Studies of the emergence and/or spread of antimicrobial-resistant pathogens in human populations
- Research on therapeutic approaches that target resistance mechanisms
- Modification of existing antimicrobials to overcome emergent resistance
- Antimicrobial research, as related to engineered threats and naturally occurring drug-resistant pathogens, focused on development of broad-spectrum antimicrobials
- Innate immunity, defined as the study of nonadaptive immune mechanisms that recognize, and respond to, microorganisms, microbial products, and antigens
- Coccidioides immitis (added February 2008)
- Coccidioides posadasii (added February 2008)
*NIAID Category C Antimicrobial Resistance—Sexually Transmitted Excluded Organisms
Bacterial vaginosis, Chlamydia trachomatis, Cytomegalovirus, Granuloma inguinale, Hemophilus ducreyi, Hepatitis B virus, Hepatitis C virus, Herpes Simplex virus, Human immunodeficiency virus, Human papillomavirus, Neisseria gonorrhea, Treponema pallidum, Trichomonas vaginalis
