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Vol. 19. Issue 4.
Pages 446-448 (July - August 2015)
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Vol. 19. Issue 4.
Pages 446-448 (July - August 2015)
Letter to the Editor
Open Access
Asthma exacerbation and viral infection in adult patients, Brazil
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Raquel Cirlene Silva, José Nelson Couceiro, Fernando Portela Câmara
Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
Solange Valle
Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
Norma Santos
Corresponding author
nsantos@micro.ufrj.br

Corresponding author at: Departamento de Virologia - Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, CCS – Bl. I - Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ 21.941-972, Brazil.
Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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Table 1. Characteristics of patients infected with respiratory viruses.
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Dear Editor,

Asthma is a common respiratory condition associated with a significant socioeconomic burden affecting 300 million people worldwide. Environmental factors and, in children, viral respiratory infections have been associated with acute exacerbations of asthma.1 Although the impact of viral infections in adults is less clear with regard to asthma exacerbation, studies suggest that viral infections are involved in about 50% of adult asthma episodes.

We conducted a descriptive, observational, cohort study in 47 patients (38 female and 9 male) previously diagnosed with asthma, who attended the Hospital Universitário Clementino Fraga Filho (HUCFF)/Federal University of Rio de Janeiro (UFRJ) between August 2010 and November 2012. Median age was 50.2 years, ranging from 21 to 80 years. Respiratory samples (nasal/throat swabs) were obtained from participants during routine visit to the clinic and whenever the patients visited the hospital due to asthma exacerbation. Sixty-seven samples were collected during an episode of asthma exacerbation and 63 in the absence of asthma symptoms. Asthma severity was classified as mild (52.2%; n=35) and moderate/severe (47.8%; n=32). Each patient provided at least one sample during an asthma episode and one sample in the absence of asthma symptoms. The study protocol was approved by the Ethics Committee of the HUCFF/UFRJ, Rio de Janeiro, Brazil (protocol number 011/10) and informed consent was obtained from all participants before the start of the study. The specimens were tested by real time or conventional PCR for presence of respiratory viruses. Statistical analysis was performed using Minitab® for Windows Release 16.0 (Minitab Inc., State College, PA, USA).

Eighteen patients (38.3%) tested positive for respiratory viruses at least once during the study; no respiratory viruses were detected in the absence of asthma symptoms. Of the 67 samples collected during asthma episodes, 20 (29.9%) were positive for respiratory viruses, namely six HAdV, six HBoV2, two HRV-A/B, two FLUVB, and one HRV-C, HRSV, and HMPV. HAdV, KIPyV, and HRV-A/B co-infections were detected in one sample. FLUVA, HPIV1-4, HCoV, HBoV1 3 and 4, and WUPyV were not detected in any of the samples examined (Table 1). One patient had two samples positive for HBoV2 and another patient had one sample positive for HRV-A/B and one for HBoV2 (Table 1). No samples collected in the absence of asthma symptoms tested positive for the viruses screened. A statistically significant association between Severity of the asthma episode was significantly associated with viral infection: 42.4% of the patients with a severe/moderate asthma episode were positive for viral infection compared to 16.7% of patients with mild episodes (p=0.015). The relative risk for viral infection in asthmatic patients in this study was found to be 2.34 (95% CI: 1.88–2.90). These data suggested that viral infections and asthma symptoms were associated, and these infections could trigger exacerbation of the disease. Indeed, the data demonstrated that an individual suffering from a viral infection were 2.34 times as likely to develop moderate or severe asthma.

Table 1.

Characteristics of patients infected with respiratory viruses.

Patient  Sex  Age (years)  Asthma attacka  Date of collection  Duration of symptoms (days)b  Virus detected 
44  MO  04/25/2011  HAdV 
    45  –  05/13/2012     
45  MO  10/18/2010  >60  FLUVB 
    46  –  05/30/2011     
    46  –  11/28/2011     
    47  04/09/2012   
31  08/03/2011  HRSV 
    32  –  05/05/2012     
29  08/23/2010  15   
    30  MO  04/04/2011  HAdV 
    30  –  06/20/2011     
    30  –  08/06/2012     
66  10/25/2010   
    67  –  07/05/2011     
    68  02/27/2012  15  HAdV 
34  10/13/2010   
    34  10/18/2010  HBoV2 
    36  –  10/16/2012     
30  10/13/2010  HBoV2 
    30  10/18/2010   
    30  02/10/2011   
    31  MO  08/18/2011   
    31  MO  09/12/2011  HBoV2 
    31  –  07/16/2012     
45  MO  08/25/2010  15  HBoV2 
    46  –  09/14/2011     
52  MO  08/11/2010  15  HAdV+KIPyV+HRV 
    52  –  02/20/2011     
    53  –  09/14/2011     
10  78  04/18/2011  15  HAdV 
    79  –  11/28/2011     
11  58  MO  08/09/2010  60  HBoV2 
    59  –  01/24/2012     
    60  MO  06/18/2012   
12  62  08/24/2010  HRV-A/B 
    62  MO  04/11/2011  15   
    62  04/10/2012  15  HBoV2 
    63  –  05/07/2012     
13  50  MO  03/28/2011  15  HRV-A/B 
    50  06/13/2011   
    50  –  03/21/2011     
    51  05/14/2012  30   
14  54  MO  05/30/2011  30  HAdV 
    55  –  07/02/2012     
15  57  10/18/2010   
    58  MO  04/22/2011  30   
    58  MO  10/31/2011  30  HAdV 
    58  –  08/22/2011  –   
16  67  09/13/2010  15   
    68  –  10/03/2011     
    69  08/13/2012  HRV-C 
17  25  MO  10/25/2010  HMPV 
    26  –  04/18/2011     
18  48  08/25/2010  FLUVB 
    48  –  04/12/2011     
    49  –  12/13/2011     
a

Based on reference 2: M, mild; MO, moderate; S, severe.

b

Duration of symptoms at the time of sample collection. (–), no asthma symptoms.

In our study only nine out of 47 patients were male. Many epidemiological studies suggest that women are at increased risk of developing adult-onset asthma and also suffer from more severe disease than men. These gender differences appear to result from biological sex differences as well as sociocultural and environmental differences. Biological sex differences include genetic, pulmonary, and immunological factors. There is compelling evidence that sex hormones are major determinants of these biological sex differences.3

Previous studies have demonstrated an association between asthma and infections with various respiratory viruses, including HRSV, HRV, HMPV, HPIV, HAdV, and FLUV.4 More recently, HBoV has been isolated from patients presenting with mild or severe asthma. In older children and in adults, HRV infections accounted for more than 50% of all viral-triggered exacerbations.5 In the present study, HBoV and HAdV were the most common viruses identified, accounting for 60% (12/20) of infections compared to HRV detected in 15% (3/20) of cases.

The management of asthma in older adults represents a substantial cost burden associated with hospital treatment, prescriptions, health-care, and management of co-morbidities. Viral respiratory infections can potentially trigger asthma exacerbation in adults in general and in the elderly in particular. Therefore, development of effective treatments or vaccines to prevent such infections would have a significant impact on the burden of asthma as well as on other respiratory diseases, such as allergic rhinitis and chronic obstructive pulmonary disease (COPD).

Conflicts of interest

The authors declare no conflicts of interest.

References
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Global Initiative for Asthma (GINA) [homepage on the Internet].
Global strategy for asthma management and prevention [updated 2012].
(2012),
[2]
R.C. Silva, G.S. Mendes, M.A. Rojas, et al.
Frequency of viral etiology in symptomatic adult upper respiratory tract infections.
Braz J Infect Dis, 19 (2015), pp. 30-35
[3]
B.N. Melgert, A. Ray, M.N. Hylkema, W. Timens, D.S. Postma.
Are there reasons why adult asthma is more common in females.
Curr Allergy Asthma Rep, 7 (2007), pp. 143-150
[4]
D.E. Dulek, R.S. Peebles Jr..
Viruses and asthma.
Biochim Biophys Acta, 1810 (2011), pp. 1080-1090
[5]
J.E. Gern.
The ABCs of rhinoviruses, wheezing, and asthma.
J Virol, 84 (2010), pp. 7418-7426
Copyright © 2015. Elsevier Editora Ltda.. All rights reserved
The Brazilian Journal of Infectious Diseases
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