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Respiratory viral infection and wheezy bronchitis in childhood
Insights
Respiratory viral infections, particularly rhinoviruses, frequently trigger wheezy bronchitis in children. Host factors and developing immunity influence the incidence of this common childhood respiratory illness.
Area of Science:
- Pediatric respiratory medicine
- Virology
- Epidemiology
Background:
- Wheezy bronchitis is a common childhood illness.
- The role of respiratory viruses in its etiology is not fully understood.
- Previous studies have suggested a viral link, but specific causative agents and influencing factors require further investigation.
Purpose of the Study:
- To investigate the role of respiratory viral infections in episodes of wheezy bronchitis in children.
- To compare viral isolation rates in wheezy bronchitis with those in acute upper respiratory illness.
- To identify host factors and viral characteristics contributing to wheezy bronchitis.
Main Methods:
- Prospective study of 163 children (0-12 years) in a London general practice.
- Virological investigations during episodes of wheezy bronchitis and acute upper respiratory illness.
- Comparison of viral findings with a control group of children without wheezy bronchitis.
Main Results:
- A virus was isolated in 26.4% of 554 wheezy bronchitis episodes.
- Rhinoviruses were the most frequently isolated viruses, accounting for nearly half of all viral detections.
- Viral isolation patterns in wheezy bronchitis were similar to those in non-wheezy upper respiratory illness.
- Rhinovirus infections were significantly more common in children with a history of wheezy bronchitis.
Conclusions:
- Respiratory viral infections, especially rhinoviruses, can provoke wheezy bronchitis in susceptible children.
- Host factors play a crucial role in determining susceptibility to wheezy bronchitis.
- The high number of rhinovirus serotypes and lack of cross-immunity likely contribute to their prevalence.
- Maturation of immune mechanisms and acquired immunity to viruses explain the decline in wheezy bronchitis incidence with age.
Abstract:
The role of respiratory viral infection in wheezy bronchitis was studied in 163 children, aged 0-12 years, in a London general practice. Virological investigations were also performed when these same children had acute upper respiratory illness without wheeze. A virus was isolated in 146 (26.4%) of 554 episodes of wheezy bronchitis, rhinoviruses accounting for almost half of the isolations. The relative frequency with which individual viruses were isolated in wheezy bronchitis was similar to that in acute upper respiratory illness in 180 other children who had never had wheezy bronchitis. The large number of isolations of rhinoviruses in wheezy bronchitis is probably due to their numerous serotypes and the absence of cross-immunity between them. Our findings have confirmed that infection by respiratory viruses can provoke wheezy bronchitis in certain children, in whom host factors are an important predeterminant. In children with a previous history of wheezy bronchitis infection by rhinoviruses was associated significantly more often with such an episode than with upper respiratory illness. The maturation of protective mechanisms, including the acquisition of specific immunity to a progressively larger number of viruses, could explain the fall in the age-incidence of wheezy bronchitis.