The inhalation, or pulmonary, form of anthrax usually occurs 1 to 60 days after exposure, although longer incubation periods can follow milder degrees of exposure. During the initial stage of the disease, nonspecific, influenza-like symptoms are common: myalgias, cough, low-grade fever, nonproductive cough, malaise, nausea, vomiting, chills, sweating, headache, and shortness of breath. Usually there follows a period of 1 to 3 days of improvement and then the rapid progression of high fever, severe respiratory distress, and cardiovascular collapse, often leading to shock and death within 24 to 36 hours. Massive mediastinal adenopathy occurs often. Person-to-person spread is not a significant risk because the main lesions are in the mediastinal lymph nodes and surrounding tissue. The mortality rate is 90% to 100% among untreated patients but 30% to 50% if patients are treated, depending on how quickly treatment with antibiotics is initiated.
B. anthracis is susceptible to common antibiotics, including ciprofloxacin, penicillin G, or tetracyclines.
Smallpox is a severe, highly contagious, febrile viral disease caused by a DNA virus of the orthopoxvirus genus. These viruses are among the largest and most complex of all viruses. There is an incubation period of 10 to 12 days after exposure. The illness begins with the symptoms of fever, fatigue, and myalgias. A distinctive erythematous, vesicular rash, centrifugal in distribution, then develops over the next 1 to 2 days, with the lesions appearing early on the face (Fig. 8-121) and arms, with relative sparing of the trunk. As the disease progresses, lesions appear on the trunk. The lesions are uniform in their stage of development and are often umbilicated (Fig. 8-122). After approximately 2 weeks, the lesions form crusts, which fall
away after 3 to 4 weeks. The case-fatality rate is 30% to 40% or more. The last naturally occurring case of smallpox was in 1977 in Somalia. In 1980, the World Health Organization officially declared that smallpox was eradicated worldwide as a result of a global vaccination program. Although smallpox was long feared as one of the most devastating infectious diseases, its potential for devastation today is far greater than ever before. In a now highly susceptible, mobile population, medically ignorant of this infection once considered eradicated, smallpox could spread widely and rapidly throughout the world. The presence of even one case would constitute an international health emergency.
Plague is caused by a gram-negative, non-spore-forming bacillus, Yersinia pestis. Natural human infection usually follows the bite of an infected flea and is less commonly caused by droplet spread from a person or cat with pneumonic plague. Plague occurs in three forms: bubonic, pneumonic, and septicemic. In the case of pneumonic plague, after an incubation period of 1 to 6 days, there is the fulminant onset of high fever, chills, extreme malaise, headache, and myalgias. Within 24 hours, cough with hemoptysis occurs. Dyspnea rapidly develops, and respiratory and cardiovascular collapse ensue. The mortality rate is 100% if the disease is untreated and could be as high as 50% even with treatment.
In the bubonic form of plague, sudden flulike symptoms develop after an incubation period of 2 to 8 days. At about the same time, the patient notices the presence of an oval, elevated, 1-to 10-cm, firm, nonfluctuant mass associated with intense pain in the enlarged regional lymph nodes, known as a bubo. Gangrene of the extremities is one of the common manifestations of plague, accounting for the name of the ''Black Death'' throughout the ages. The mortality rate is 50% to 60% if the disease is untreated. Treatment for all forms of plague is with streptomycin, doxycycline, or ciprofloxacin.
The typical distribution of lesions in six common skin disorders is shown in Figure 8-123.
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