Clinical
Effects of Smallpox: Pathophysiology of Natural Infection
Infection
Infection
begins when the virus comes into contact with the oropharyngeal
or respiratory mucosa. The infectious dose is unknown but is believed
to be only a few virions. (9:4)Virus multiplication
then occurs in the regional lymph nodes. An asymptomatic viremia
develops on about the third or fourth day, followed by multiplication
of virus in the spleen, bone marrow and lymph nodes. (9:4) A
secondary viremia begins on about the eighth day of infection,
and is accompanied by the first symptoms of illness – the
prodrome, characterized by fever and other symptoms. The virus,
contained in leukocytes, then localizes in small blood vessesl
of the dermis and beneath the oral and pharyngeal mucosa and subsequently
infects adjacent cells. (9:4) In the skin,
the virus localizes in small blood vessels of the dermis and in
the oral and pharyngeal mucosa. The result is the characteristic
rash. (19:5)

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