Virus
Parainfluenza virus
Leading cause of croup in children
PAIR-uh-in-floo-EN-zuh VY-rus
High-yield clue
A barking (seal-like) cough and inspiratory stridor from croup (laryngotracheobronchitis) is the classic parainfluenza clue.
Overview
Enveloped negative-sense RNA paramyxoviruses (human types 1-4) that infect the respiratory tract and are the leading cause of croup, useful for linking upper-airway obstruction vocabulary to a viral cause.
Classification
- RNA virus
- Negative-sense single-stranded RNA
- Enveloped, HN and F glycoproteins
- Family Paramyxoviridae (Respirovirus and Orthorubulavirus)
Lab & identification clues
- Respirovirus/Orthorubulavirus classification concept
- Multiplex respiratory PCR panel vocabulary
- Nasopharyngeal sampling concept
- Subglottic narrowing ('steeple sign') imaging vocabulary
Associations
- Croup (laryngotracheobronchitis) in young children
- Also causes bronchiolitis and pneumonia
- Respiratory-droplet and contact spread
- Seasonal outbreak epidemiology
Commonly confused with
- Respiratory syncytial virus
- Human metapneumovirus
Frequently asked questions
What is Parainfluenza virus?
Enveloped negative-sense RNA paramyxoviruses (human types 1-4) that infect the respiratory tract and are the leading cause of croup, useful for linking upper-airway obstruction vocabulary to a viral cause.
What are the lab clues for Parainfluenza virus?
Lab clues for Parainfluenza virus include Respirovirus/Orthorubulavirus classification concept, Multiplex respiratory PCR panel vocabulary, Nasopharyngeal sampling concept, and Subglottic narrowing ('steeple sign') imaging vocabulary.
What is Parainfluenza virus commonly confused with?
Parainfluenza virus is commonly confused with Respiratory syncytial virus and Human metapneumovirus.
Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.