A new and potentially more pathogenic group of human rhinoviruses, rhinovirus group C, is associated with asthma attacks in children. Moreover, asthma attacks in children infected with the new subtype (HRVC) of the virus that causes common colds would be more severe, an Australian study suggests.

In a study of 128 children presenting with asthma, the new rhinovirus was found in 60% of children with acute asthma and it was associated with higher asthma severity scores.

Children aged 2–16 yrs presenting to the emergency department with an asthma attack were included in the study. An asthma attack severity score (from 5 mild to 15 severe) was assigned to each child based on clinical characteristics. Nasal samples were tested for viruses causing respiratory infections.

The majority of the children studied had moderate to severe asthma (85.2%) and 98.9% were admitted to hospital. The overwhelming majority of children (92.2%) had a respiratory infection at the time of their asthma attack, and most infections (87.5%) were caused by the common cold virus HRV. Other respiratory viruses were detected in 14.8% of children, most of whom also had HRV. HRVC were present in the majority of children with acute asthma (59.4%) and associated with more severe asthma.

When looking at asthma attack severity, researchers from the University of Western Australia in Perth found that the new types of common cold virus were more commonly found in asthmatics whose attacks were significantly more severe. The majority (59.4%, 76 out of 128) of children with acute asthma were infected with an HRVC strain compared with 26.6% (34 out of 128) whose only HRV infection was with a strain from the HRVA or B group. The 76 children infected with HRVC not only had more severe attacks than those infected with a previously known HRV group; their attacks were also more severe than those of all other children who were not infected with a new HRVC type.

“This is really important because the rhinovirus, predominantly new HRVC strains of rhinovirus, is responsible for more serious disease than previously believed and causes significant morbidity for children with asthma,” explains first author Joelene Bizzintino, BSc (Hons), School of Paediatrics & Child Health, University of Western Australia, Perth/WA, Australia.

These novel findings are of fundamental importance to the understanding of asthma in children.

“What we need to do now is determine why the new HRVC strains of rhinovirus are so pathogenic and come up with treatment strategies to avoid the severe asthma attacks with which they are associated,” says Bizzintino.

Reference:

Bizzintino J. et al. Eur Respir J. 2010 Aug 6. [Epub ahead of print]