Parainfluenza Viruses
Date: 2 سال قبل
author: AmirAbad
Parainfluenza Viruses
Clinical Manifestations
Parainfluenza viruses cause
mild or severe upper and lower respiratory tract infections, particularly in
children.
Classification and
Antigenic Types
Human parainfluenza viruses
are divided into types 1, 2, 3, and 4; type 4 consists of A and B subtypes.
Pathogenesis
Transmission is by droplets
or direct contact. The virus disseminates locally in the ciliated epithelial
cells of the respiratory mucosa.
Host Defenses
Nonspecific defenses,
including interferon, are followed by the appearance of secretory and humoral
antibodies and cell-mediated immune responses.
Epidemiology
Parainfluenza virus
diseases occur worldwide; they are usually endemic but sometimes epidemic.
Primary infections occur in young children; reinfection is common but results
in milder disease.
Diagnosis
Clinical symptoms are
nonspecific. Laboratory diagnosis is made by detecting viral antigen, by
isolating the virus, or by detecting a rise in antibody titer or elevated IgG-
and IgA- (IgM-) antibodies in a single serum.
Control
No vaccine is available
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