Predominance of rhinovirus in the nose of symptomatic and asymptomatic infants

Chronic Rhinoviral Infection in Lung Transplant Recipients

RATIONALE

Lung transplant recipients are particularly at risk of complications from rhinovirus, the most frequent respiratory virus circulating in the community.

OBJECTIVES

To determine whether lung transplant recipients can be chronically infected by rhinovirus and the potential clinical impact.

METHODS

We first identified an index case, in which rhinovirus was isolated repeatedly, and conducted detailed molecular analysis to determine whether this was related to a unique strain or to re-infection episodes. Transbronchial biopsies were used to assess the presence of rhinovirus in the lung parenchyma. The incidence of chronic rhinoviral infections and potential clinical impact was assessed prospectively in a cohort of 68 lung transplant recipients during 19 mo by screening of bronchoalveolar lavages.

MEASUREMENTS AND MAIN RESULTS

We describe 3 lung transplant recipients with graft dysfunctions in whom rhinovirus was identified by reverse transcriptase-polymerase chain reaction in upper and lower respiratory specimens over a 12-mo period. In two cases, rhinovirus was repeatedly isolated in culture. The persistence of a unique strain in each case was confirmed by sequence analysis of the 5'NCR and VP1 gene. In the index case, rhinovirus was detected in the lower respiratory parenchyma. In the cohort of lung transplant recipients, rhinoviral infections were documented in bronchoalveolar lavage specimens of 10 recipients, and 2 presented with a persistent infection.

CONCLUSIONS

Rhinoviral infection can be persistent in lung transplant recipients with graft dysfunction, and the virus can be detected in the lung parenchyma. Given the potential clinical impact, chronic rhinoviral infection needs to be considered in lung transplant recipients.

Human rhinoviruses in otitis media with effusion

Frequent viral upper respiratory tract infections (URTI) are considered to be risk factors for otitis media with effusion (OME). Atopy has also been associated with both OME and viral infections. The aim of this study was to evaluate the presence of viruses in middle ear effusions (MEE) in children 2-7 yr old with OME, and to determine risk factors for virus detection in the MEE. MEE samples, collected at the time of myringotomy from 37 children with OME were assessed. Physical examination, skin prick tests and a standardized questionnaire on OME and allergy were also performed. Viral RNA was detected by the use of reverse transcription PCR (RT-PCR). Fifteen samples (40.5%) were positive for rhinovirus (RV). One enterovirus and no other respiratory viruses were detected. Two out of five (40%), 3/7 (43%) and 10/25 (40%) were positive for RV in acute, subacute and chronic cases, respectively. Children with frequent episodes of OM, with early onset of OM (<2 yr old), and a positive family history of allergy had a statistically increased risk of RV detection. The two groups were comparable with respect to all other parameters examined. RV is the predominant virus recovered by RT-PCR in the middle ear cavity of children with asymptomatic OME, especially those with a history of longstanding OME or repeated episodes, or children with a family history of allergy. Interactions between allergy and RV infections are likely to predispose to middle ear disease.

Community-acquired pathogens associated with prolonged coughing in children: a prospective cohort study

A 2-year prospective study was performed of children with prolonged coughing to investigate the frequency of different respiratory pathogens, the rate of mixed infections, and possible differences in severity of disease between single and mixed infections. Sera from 135 children (136 episodes of prolonged coughing lasting 1-6 weeks) were tested for antibodies to different viruses and bacteria. Swabs were taken for culture and PCR to detect different viral and bacterial pathogens. One or more pathogens were found in 91 (67%) patients. One infectious agent was found in 49 (36%) patients, two agents in 35 (26%) patients, and more than two agents in seven (5%) patients. The most frequent pathogens encountered were rhinovirus (n = 43; 32%), Bordetella pertussis (n = 23; 17%) and respiratory syncytial virus (n = 15; 11%). The most frequent mixed infection was B. pertussis and rhinovirus (n = 14; 10%). No significant differences in clinical symptoms were observed between patients with or without pathogens; however, patients with mixed infections were significantly older. There was a strong seasonal influence on the number of infections, but not on the number of mixed infections. In children with prolonged coughing, there was a high frequency of mixed infections regardless of the season. However, mixed infection was not associated with increased disease severity. No clinical symptoms were found that allowed discrimination between specific pathogens.

Viruses as the causative agent related to 'dampness' and the missing link between allergen exposure and onset of allergic disease

Asthma and asthma-like symptoms occur more often among people living in humid indoor climates. It has been postulated that the higher concentration of allergens in these environments is the cause for the increase in the number of affected people. However, poor correlations between allergen concentration and symptoms indicate a missing link between allergen exposure and onset of asthma. Respiratory viruses have been identified in up to 85% cases of asthma or exacerbations of asthma. The missing link between respiratory diseases and humid indoor climates could therefore be attributed to viruses. The infectious effectiveness of respiratory viruses depends strongly on the environment where the viruses are spread. For respiratory viruses, survival and infectivity are dependent on temperature and relative humidity. A direct link between virus-induced inflammation and the asthmatogenic process has been proposed. Therefore, a more effective spreading of viral infections in damp indoor climates is likely to represent the main cause for the increased prevalence of asthma in these environments. Moreover, the incidence of viral infections is higher in patients with asthma compared with that in control subjects. Therefore, a humid indoor climate could also represent a higher risk for persons already sensitized to one or more allergens.

PRACTICAL IMPLICATIONS

In epidemiological studies where the relationship between moisture in the indoor climate, respiratory symptoms and exposure to allergens is investigated it will be necessary to analyze the role of respiratory viruses in relation to respiratory symptoms. Today, the necessary techniques to address the presence of viruses [e.g. polymerase chain reaction (PCR), antibodies] are highly sensitive. In order to further our understanding of why the frequency of asthma and atopic diseases is still increasing, it is mandatory to implement these methods.