Clinical disease:The prodromebegins with the sudden onset of fever, chills, back pain,
headache, malaise, and sometimes nausea, vomiting, abdominal pain, and confusion. Diarrhea
is less frequent. Children sometimes have seizures. The prodrome usually last two to three days
but may be as long as five days. Some patients display a short-lived (12 hours) erythematous or
petechial rash.
The typical patient develops a centrifugal rash two to three days after the onset of
symptoms or very quickly after the enanthem.Typicalorordinary smallpox(Variola major)
occurs in the majority of patients. A maculopapular rash first appears on the face, hands, and
forearms. Early lesions are shotty and within 24 to 48 hours become vesicular then pustular.
The lesions then involve the palms, soles, trunk, and upper thighs. In survivors, the rash crusts
and scabs fall off in eight to nine days. Mortality for this form of the disease is 15% to 50%.
Flat malignant smallpox(10% to 20% of patients, usually unvaccinated children) present
with a severe prodrome, poorly formed papules, and dusky erythema of the face followed by
arms, back, and upper chest. The rash may progress to petechiae. Death (45% to 99% of patients)
occurs in 7 to 15 days from encephalitis or hemorrhage. Hemorrhagic fulminate smallpox
mimics hemorrhagic fever with most patients succumbing in seven days. Mortality rate is 95%
regardless of vaccination status. Those who survive to 10 days develop a maculopapular rash.
Modified smallpox(vaccino-modified, V. minor, alastrim, amaas) is seen in partially immune
patients and patients infected with a less virulent virus. The disease is mild and influenza-like
until the rash appears. The rash appears usually three to five days after the prodrome, but may
appear later. The course is short, mild, complications are rare, and mortality is very low. Other
mild forms of disease include an influenza-like illness and pharyngeal disease that is mild and
presents without rash (variola sine eruptione, variola sine exanthemata).
Complicationsinclude encephalopathy, eye complications (10–20% of patients), smallpox
(viral) osteomyelitis (osteomyelitis variolosa), hemorrhagic disease particularly in pregnant
women, fetal death, and premature delivery.
Differential diagnosis: Includes acne, chickenpox, drug eruptions, generalized vaccinia or
eczema vaccinatum, insect bites, monkeypox, secondary syphilis, vaccine reactions, and viral
hemorrrhagic fever.
Treatmentis supportive. Parenteral cidofovir and imatinib mesylate (Gleevec) may have a
role in severe cases.
Plague (25,26,29)
Incubation period: Bubonic plague (from a fleabite or direct contact of the skin or mucous
membrane): two to six days. Primary plague pneumonia from inhalation of infected droplets:
one to three days. Septicemic plague may be primary or secondary. Incubation periods for
gastrointestinal or pneumonic plague are variable.
Contagious period: Antibiotic treatment rapidly reduces contagion.
Clinical disease: Patients present with one or more of five clinical syndromes: (i) classic
bubonic plague; (ii) septicemic plague; (iii) upper respiratory infections; (iv) nonspecific febrile
illnesses, and (v) gastrointestinal or urinary tract infections (95).
Bubonic Plague
Patients present with sudden onset of fever, chills, headache, and malaise. A papule, vesicle,
pustule, ulcer, or eschar may be present at the inoculation site. Regional nodes enlarge within
24 hours (1 to 10 cm), are tender, inflamed, and become fluctuant.
Septicemic Plague
The symptoms (fever, chills, malaise, headache, and gastrointestinal symptoms) and signs
(tachycardia, tachypnea, and hypotension) of septicemic plague are similar to those of other
forms of gram-negative septicemia. One-half of the patients have abdominal pain. Generally,
there is a paucity of specific findings. Primary septicemic disease occurs from cutaneous
exposure, but without regional lymphadenopathy. Gangrene in the extremities and tip of the
nose from small vessel thrombosis occurs (The Black Death).
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