Parainfluenza Virus 1, 2, 3

Clinical Background

Parainfluenza viruses (PIV) are the second most common cause of acute upper and lower respiratory tract infections (URI and LRTI) in the U.S. for children younger than 5 years.

Epidemiology

  • Prevalence
    • PIV causes 65% of croup cases, 20-40% of LRTIs and 20% of URIs in preschool children
    • 3/1000 cases of croup require medical attention per year
  • Age – usually in children 3-5 years
  • Transmission – via respiratory droplet

Classification

  • PIV types 1, 2, and 3 are clinically the most common
    • Types 1 and 2 are the primary causes of laryngotracheobronchitis (croup)
      • Seasonal biennial outbreaks in the U.S., currently occurring in the fall of odd-numbered years
    • Types 1 and 3 are common in early childhood, causing localized outbreaks in nurseries, schools, orphanages, and pediatric wards
    • Type 3 is second only to respiratory syncytial virus (RSV) as a cause of bronchiolitis and pneumonia in infants
      • Can cause parotiditis similar to mumps
      • Peak is late spring
    • PIV type 4 is less well-studied but also causes URI and LRTI

Organism

  • An enveloped and single-stranded RNA virus belonging to the Paramyxoviridae family
  • Other viruses in this family include RSV, mumps, measles, metapneumovirus (hMPV), Hendra and Nipah viruses

Clinical Presentation

  • May present as mild upper respiratory illness, croup, bronchiolitis or pneumonia
    • Older children and adults tend to have milder disease

Treatment

  • Treatment is symptomatic and supportive.

Diagnosis

Indications for Testing

  • Flu-like illness during PIV season

Laboratory Testing

  • Clinical diagnosis usually suffices
  • Sequential panel antibody testing
    • Supports the diagnosis
    • Cross reactivity can occur with assays for IgG, particularly due to the mumps virus
    • Usually not necessary, except possibly during epidemic events
  • Viral culture – gold standard
    • Conventional culture requires up to 7 days
    • Rapid culture requires less time (24-48 hours)
  • Direct fluorescent antibody (DFA) stain is most rapid diagnostic test
    • Also includes testing for influenza, adenovirus, RSV, and hMPV
    • Less sensitive than culture, PCR.
  • Polymerase chain reaction (PCR) – most sensitive, some assays can detect parainfluenza 4

Differential Diagnosis

  • Adenovirus
  • Bordetella pertussis
  • Chlamydia pneumoniae
  • Enterovirus
  • Influenza
  • Metapneumovirus
  • Mycoplasma pneumoniae
  • Respiratory syncytial virus

Indications for Laboratory Testing

  • Tests generally appear in the order most useful for common clinical situations
  • Click on number for test-specific information in the ARUP Laboratory Test Directory
Test Name and Number Recommended Use Limitations Follow Up
Respiratory Viruses DFA with Reflex to Viral Culture 0060281
Method: Direct Fluorescent Antibody Stain

Confirm presence of viral infection

Sensitivity of DFA methodology is dependent on the adequacy of the specimen

  
Parainfluenza Virus Antibodies (1, 2, 3), IgG & IgM 0051084
Method: Enzyme-Linked Immunosorbent Assay

Parainfluenza virus antibody testing might be indicated if, during flu season, a rapid influenza test result is negative

Note: Panel test is recommended over the individual virus tests since cross-reactivity can occur

 

  
Viral Culture 0065008
Method: Cell Culture

Historically the gold standard test for identifying parainfluenza virus

    
Respiratory Viruses Rapid Culture 2001504
Method: Cell Culture/Immunofluorescence

Respiratory viruses that can be isolated include influenza A & B, adenovirus, RSV, and parainfluenza types 1,2,3

Other viruses such as HSV or CMV will not be routinely detected in this culture

Test has decreased sensitivity for detection of adenovirus

  
Additional Tests Available
 
 
Click the plus sign to expand the table of additional tests.
Test Name and NumberComments
Parainfluenza Virus 1 Antibody, IgM 0051070
Method: Enzyme-Linked Immunosorbent Assay
Parainfluenza Virus 2 Antibody, IgG 0051071
Method: Enzyme-Linked Immunosorbent Assay
Parainfluenza Virus 2 Antibody, IgM 0051072
Method: Enzyme-Linked Immunosorbent Assay
Parainfluenza Virus 3 Antibody, IgG 0051082
Method: Enzyme-Linked Immunosorbent Assay
Parainfluenza Virus 3 Antibody, IgM 0051083
Method: Enzyme-Linked Immunosorbent Assay
Parainfluenza Virus 1 Antibody, IgG 0051068
Method: Enzyme-Linked Immunosorbent Assay
Respiratory Viruses DFA 0060289
Method: Direct Fluorescent Antibody Stain
Viral Culture 0065008
Method: Cell Culture