Parainfluenza virus type 3
Overview
Parainfluenza is an influenza-like viral disease that can cause croup, upper respiratory tract infection, pneumonia or bronchiolitis. Type 3 virus occurs during spring and summer in temperate climates but can continue into autumn.
Symptoms
* Mild flu-like symptoms * Cold-like symptoms * Cold * Sore throat * Cough * Shortness of breath * Fever * Runny nose * Upper respiratory tract illness * Lower respiratory tract illness * Pneumonia * Bronchitis * Bronchiolitis * Croup
Causes
Transmission of influenza occurs through inhalation of a respiratory droplet from an infected person or by indirect contact with a contaminated object, such as a drinking glass or other items contaminated with respiratory secretions. The influenza virus then invades the epithelium of the respiratory tract, causing inflammation and desquamation. One of the remarkable features of the influenza virus is its capacity for antigenic variation into numerous distinct strains, allowing it to infect new populations that have little or no immunologic resistance. Antigenic variation is characterized as antigenic drift (minor changes that occur yearly or every few years) and antigenic shift (major changes that lead to pandemics). Influenza viruses are classified into three groups: -Type A, the most prevalent, strikes every year, with new serotypes causing epidemics every 3 years. -Type B also strikes annually but causes epidemics only every 4 to 6 years. -Type C is endemic and causes only sporadic cases. Each year, tens of millions of people in the United States get the flu; about 114,000 people get sick enough to be hospitalized, and about 36,000 people die.
Treatment
Treatment of uncomplicated influenza includes bed rest, adequate fluid intake, aspirin or acetaminophen (in children) to relieve fever and muscle pain, and dextromethorphan or another antitussive to relieve nonproductive coughing. Prophylactic antibiotics aren't recommended because they have no effect on the influenza virus. Amantadine and rimantadine (antiviral agents) have proven to be effective in reducing the duration of signs and symptoms of influenza A infection.Oseltamivir and zanamivir are effective against influenza A and B infection. In influenza complicated by pneumonia, supportive care (fluid and electrolyte supplements, oxygen, and assisted ventilation) and treatment of bacterial superinfection with appropriate antibiotics are necessary. No specific therapy exists for cardiac, central nervous system, or other complications.