staff to have appropriate PPE in place and a suitable isolation room prepared for the patient [35, 36].
Table 23.3 Comparison of coronavirus infections, seasonal influenza, and 1918 pandemic influenza
| SARS | MERS | COVID‐19a | Seasonal influenza (annual) | 1918 pandemic influenza | |
|---|---|---|---|---|---|
| R0b | 3 | 1.9‐3.9 | 1.95‐3.28 | 0.9‐2.1 | 1.4‐2.8 |
| Total cases | 8906 | 2562 | 131,909,792 | 1 billion | 500 million |
| Deaths | 744 | 881 | 2,854,276 | 389,000 | 50 million |
| Case fatality rate (%) | 8.4 | 34.4 | 2.2 | 0.04 | 10 |
a As of April 5, 2021 [63].
b Basic reproduction number: number of new cases that can develop from one confirmed case.Sources: From [62–67].
Biological Weapons
The CDC categorizes bioterrorism agents as shown in Box 23.1 [37]. Some of the listed agents, such as botulinum toxin and ricin, are not infectious diseases, but rather biological toxins.
Anthrax
The symptoms of anthrax are determined by the route of transmission of the bacterium, Bacillus anthracis, which causes the infection. There are three forms of anthrax: cutaneous, gastrointestinal, and inhalational [38, 39].
Cutaneous anthrax presents as a small, painless, pruritic papule, which progresses to a vesicle that ruptures and erodes, leaving a necrotic ulcer that later gets covered with a black, painless eschar. Pathognomonic features of anthrax include the presence of an eschar, lack of pain, and edema out of proportion to the size of the lesion. Associated symptoms include swelling of adjacent lymph nodes, fever, malaise, and headache. Cutaneous anthrax is caused by B. anthracis entering a cut or abrasion in exposed areas of the body such as the face, neck, arms, and hands. The case‐fatality rate can be as high as 20% without antibiotic therapy, but 1% with therapy.
Gastrointestinal anthrax presents with symptoms that are more non‐specific. There are two forms: oropharyngeal and intestinal. Oropharyngeal anthrax starts with edematous lesions at the base of the tongue or tonsils that progress to necrotic ulcers with a pseudomembrane. Sore throat, fever, cervical adenopathy, and profound oropharyngeal edema are associated symptoms. The intestinal form of anthrax initially presents with fever, nausea, vomiting, and abdominal pain and tenderness that may progress to hematemesis, bloody diarrhea, and abdominal swelling from hemorrhagic ascites. Gastrointestinal anthrax is caused by consumption of meat contaminated with anthrax. The case‐fatality rate of gastrointestinal anthrax is estimated to be 25‐60%.
Inhalational anthrax initially causes non‐specific symptoms that mimic influenza. These early symptoms are low‐grade fever, non‐productive cough, malaise, and myalgias. Two to three days later, the patient rapidly progresses to severe dyspnea, profuse sweating, high fever, cyanosis, and shock. As many as half of patients develop hemorrhagic meningitis. It is critical that EMS personnel attempt to distinguish any influenza‐like illness from anthrax, because of the narrow window of opportunity for successful treatment. Nasal congestion and rhinorrhea are not common with inhalational anthrax, but more common with influenza‐like illness. Further, shortness of breath is more common in inhalational anthrax and less common with influenza‐like illness. Chest x‐ray demonstrates mediastinal widening or pleural effusion. These findings are the most accurate predictors of inhalational anthrax. Inhalational anthrax can be caused by inhalation of spores, commonly seen following intentional release of aerosolized anthrax, or from the processing of materials from infected animals, such as goat hair. The case‐fatality rate of inhalational anthrax can be as high as 97% without antibiotics and remain as high as 75% despite antibiotic treatment. Human‐to‐human transmission of any form of anthrax is rare.
Box 23.1 Centers for Disease Control and Prevention categorization of bioterrorism agents
Category A
High‐priority agents include organisms that pose a risk to national security 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; and
require special action for public health preparedness.
Anthrax (Bacillus anthracis)
Botulism (Clostridium botulinum toxin)
Plague (Yersinia pestis)
Smallpox (variola major)
Tularemia (Francisella tularensis)
Viral hemorrhagic fevers (filoviruses, e.g., Ebola, Marburg, and arenaviruses, e.g., Lassa, Machupo)
Category B
Second highest priority agents include those that:
are moderately easy to disseminate
result in moderate morbidity rates and low mortality rates; and
require specific enhancements of CDC’s diagnostic capacity and enhanced disease surveillance.
Brucellosis (Brucella species)
Epsilon toxin of Clostridium perfringens
Food safety threats (e.g. Salmonella species, Escherichia coli O157:H7, Shigella)
Glanders (Burkholderia mallei)
Melioidosis (Burkholderia pseudomallei)
Psittacosis (Chlamydia psittaci)
Q fever (Coxiella burnetii)
Ricin toxin from Ricinus communis (castor beans)
Staphylococcal enterotoxin B
Typhus fever (Rickettsia prowazekii)
Viral encephalitis (alphaviruses, e.g., Venezuelan equine encephalitis, eastern equine encephalitis, western equine encephalitis)
Water safety threats (e.g., Vibrio cholerae, Cryptosporidium parvum)
Category C
Third highest priority agents include emerging pathogens that could be engineered for mass dissemination in the future because of:
availability