Accessibility / Report Error

Human rhinovirus infections in symptomatic and asymptomatic subjects


The role of rhinovirus asymptomatic infections in the transmission among close contacts subjects is unknown. We tested health care workers, a pair of one child and a family member and immunocompromised patients (n =191). HRV were detected on 22.9% symptomatic and 3.6% asymptomatic cases suggesting lower transmission among contacts.

symptomatic; asymptomatic; rhinovirus infection


Human rhinovirus infections in symptomatic and asymptomatic subjects

Camargo, C.N.; Carraro, E.; Granato, C.F.; Bellei, N.* * Corresponding Author. Mailing address: Rua Pedro de Toledo, 781, andar 15. Vila Clementino, São Paulo-SP, Brazil. ZIP CODE: 04039-032.; Tel/Fax.: +55 (11) 50815394.; E-mail:

Laboratório de Virologia Clínica, Departamento de Medicina, Universidade Federal de São Paulo, SP, Brasil


The role of rhinovirus asymptomatic infections in the transmission among close contacts subjects is unknown. We tested health care workers, a pair of one child and a family member and immunocompromised patients (n =191). HRV were detected on 22.9% symptomatic and 3.6% asymptomatic cases suggesting lower transmission among contacts.

Key words: symptomatic, asymptomatic, rhinovirus infection

Rhinovirus infections are among the most frequent causes of the common colds (18). It is the most common etiology of viral respiratory infections among diverse populations, including adults, children and more recent studies have linked HRVs to more severe lower respiratory illnesses in otherwise healthy young children (11-12), immunocompromised (4,6), and elderly patients. (5,13, 23). In Brazil, there are few HRV studies, Arruda (1991), realized the first Brazilian study detecting a 45.5% rate on symptomatic children in Fortaleza-CE. Another study realized in Salvador-BA also showed a high prevalence (48.5%) (Souza ,2003). The only study describing adults was realized by Bellei and colleagues (2007) detecting 37.7%.

The dynamic of rhinovirus transmission is relevant to address for the epidemiology characteristics of infection within families, schools and nosocomial outbreaks. Rhinovirus can be easily transmitted from person to person mainly through hand contact with infected respiratory secretions (15).Studies of asymptomatic infected individuals pointed to 15-30% rates (9,19, 14, 20, 7, 19) of HRV infection but the role of infected subjects as reservoirs for secondary cases infections is unknown.

Many studies have investigated the occurrence of rhinovirus among community cases but there is a lack of information about the frequency of rhinovirus asymptomatic cases. We investigated HRV infections rates on selected populations of a pair of one child and one family member, health care workers (HCW), and immunocompromised patients with and without respiratory symptoms from June to September.

In this study, a total of 191 nasal swab (NS) specimens were collected from three groups. One hundred and eleven health care workers (HCW) from São Paulo Hospital, 36 pairs of one child and one family member and 8 blood marrow transplanted hospitalized patients (BMT). They were considered eligible symptomatic patients if possible viral etiology within 7 days of symptoms onset. The clinical criterion was presentation of at least one respiratory symptom (cough, sore throat, or nasal congestion) and one constitutional symptom (headache, malaise, myalgia, chills). For asymptomatic patients the criteria was the absence of respiratory symptoms up to one week before sampling. All subjects were interviewed by a research team after evaluation by a physician. Written informed consent was obtained from all adult participants; parents provided consent on behalf of children participants and a questionnaire was applied including demographic data, place of work, their clinical presentation and household children contact.

The symptomatic group included subjects with acute respiratory infections (ARI): children, BMT patients and health care workers. Theasymptomatic group included one parent of each symptomatic children, health care workers caring for BMT symptomatic patients or others referring a close contact with symptomatic patient in the hospital.

The nasal swab was obtained from the single nostril from a depth of 2-3 cm by using a sterile swab that was then inserted into a vial containing 2.0 ml of viral transport medium (Cultilab, Brazil). The samples were immediately transported to the Clinical Virology Laboratory for routine respiratory viruses testing. All samples were stored at -70ºC until analyzed.

For each sample the viral RNA was extracted using QIAamp Viral RNA extraction Kit (QIAGEN, Germany), according manufacturer´s instructions. Amplification of 5'NCR and VP4/VP2 genes of HRV was done by RT-PCR assay described elsewhere (17-18), with minor modifications. The eluted RNA was transcribed into cDNA with Moloney Murine Reverse Transcriptase (MMLV-RT; Invitrogen, USA) and virus specific oligonucleotide primer, for 1 h at 37°C. After, MMLV-RT denaturation at 70°C, virus-specific oligonucleotide primer (0.6µM), 2.5U Platinum Taq DNA Polymerase (Invitrogen, USA), 1x PCR Buffer, 0.2mM each dNTP, 3.5mM MgCl2 and nuclease-free water were added. The amplification condition was performed in a thermo cycler under the following settings: initial denaturation at 95° for 10 min, followed by 40 cycles consisting of denaturation (45 sec at 95°), annealing (45 sec at 61°C), and DNA extension (1 min at 72°C). The presence of PCR products were visualized on an 1,5% agarose gel electrophoresis according to their 549bp molecular weight. Positive (HRV-39) and negative controls (water) were tested in all reactions.

Descriptive statistics consisted of the characterization of the studied individuals and the assessment of symptomatology and rhinovirus infection through calculation of the respective percentages, median value and range. Bivariate analysis consisted of Fisher's Exact Test for the comparison of categorical values, with a significance level of p < 0.05. In multivariate analysis, non-conditional logistic regression was used to identify associations between presence of symptomatology, groups of individuals and rhinovirus infection status. All reported values are two-tailed. The dependent variable was presence of rhinovirus infection and the independent variables were presence of symptomatology and groups of individuals. The results were presented as odds ratio (OR) with the respective 95% confidence interval (CI) and p value. All data were entered into and analyzed by using SPSS version 11.0 (SPSS Inc., Chicago, IL, USA).

Epidemiological and clinical characterization of patients is shown in Table 1.

A total of 191 samples from both symptomatic (81) and asymptomatic cases (110) were tested for the presence of rhinovirus and 23 samples (12%) were positive. HRV was detected in 23.5% (19/81) of symptomatic subjects, compared with 3.6% (4/110) of asymptomatic subjects. The HRV infection was associated with the presence of symptoms [p <0.0001, OR 8.1 (95% CI 2.6-25.0)].

Table 2 shows the HRV infection rates among symptomatic and asymptomatic individuals, divided by groups. Six isolated cases of symptomatic parents negative for HRV were excluded from this analysis. There were no significant associations.

The symptoms reported by symptomatic group were fever (38.5%), coryza (86.7%), cough (74.7%), headache (21.7%), sore throat (35%), myalgia (12%). Wheezing was observed in 39% of children, but none of them were HRV positive. The symptoms among positive children cases were coryza (100%), cough (77.8%) and fever and sore throat (22%).

The rate of rhinovirus infection among a pair of asymptomatic parent of a rhinovirus symptomatic child was 2.8% (1/36). This was the only case with a close contact with a laboreatory confirmed patient. The others three asymptomatic infection had no close contact with positive symptomatic studied patients. Two symptomatic patients reported close contact a BMT patient and his nurse.

Rhinovirus infections occurred all over the year in Brazil (2). There is a lack of studies about asymptomatic rhinovirus infections. The majority of reported data regarding asymptomatic rhinovirus infections have been conducted in hospitalized children elsewhere and high rates were reported - 12% to 45% (16,14,7,3). Jartti et al. (2008) reviewed many studies describing asymptomatic subjects with high respiratory virus detection rates using PCR techniques. Van Kraajj and colleagues (2005) identified etiology in 63% and 9% of symptomatic and asymptomatic adult stem cell transplants recipients respectively, and rhinovirus was the predominant pathogen detected.

In our study, HRV was detected more frequently in symptomatic than asymptomatic individuals as previous reported (21,22,10) and a low rate as identified by Johnson et al. (1993) in their study among in immunocompetent adults (4%). Discrepancies among different studies may be explained by the fact that most of them included hospitalized children instead of community population. Indeed nosocomial transmission may occur without clinical expression.

Health care workers group had a 25.8 % rate. Bellei and colleagues (2007) reported the detection of HRV in 37.7% of symptomatic health care workers samples. Professional profile is an important transmission pathway in hospitals. Long-term clinical studies can clarify the impact of this reservoir in the transmission of the virus for patients (10).

We found a high frequency of rhinovirus infection in parents than health care works. The study from Bellei and colleagues (2008) also reported that 39% of those HCW had exposure to children up to 5 years old and rhinoviruses were detected in half of the personnel from pediatric wards.

Despite of the small number of subjects included, our study showed lower detection in selected asymptomatic individuals in contrast to previous studies that found higher frequencies on epidemiological surveys. Further studies would contribute to better understand the dynamic of rhinoviruses infections.


We acknowledge Dr. Eurico Arruda (FMRP-USP) for providing HRV 39 isolate.

The authors acknowledge the financial support of Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP Project number: 07/01166-9), and Coordenação de aperfeiçoamento de pessoal de nível superior (CAPES).

Submitted: June 02, 2011

Returned to authors for corrections: August 22, 2011

Approved: June 07, 2012

  • 1. Bellei, N.; Carraro, E.; Perosa, A.H.; Benfica, D.; Granato, C.F.(2007). Influenza and rhinovirus infections among health-care workers. Respirology 12:100-103.
  • 2. Bellei, N; Carraro, E.; Perosa, A.; Watanabe, A.; Arruda, E.(2008). Acute Respiratory Infection and Influenza-Like Illness Viral Etiologies in Brazilian Adults. J. Med. Virol.; 80:1824-1827
  • 3. Greenberg, S.B. (2003). Respiratory consequences of rhinovirus infection. Arch Intern Med Feb 10;163 (3):278-84. Review.
  • 4. Ghosh, S. (1999). Rhinovirus infections in myelosuppressed adult blood and marrow transplanted recipients. Clin. Infect. Dis 29:528-32.
  • 5. Hicks, L.A.; Shepard, C.W.; Britz, P.H.; Erdman, D.D.; Fischer, M.; Flannery, B.L.; Peck, A.J.; Lu, X.; Thacker, W.L.; Benson, R.F.; Tondella, M.L.; Moll, M.E.; Whitney, C.G.; Anderson, L.J.; Feikin, D.R. (2006). Two outbreaks of severe respiratory disease in nursing homes associated with rhinovirus. J Am Geriatr. Soc Feb;54 (2):284-9.
  • 6. Ison, M.G.; Hayden, F.G.; Kaiser, L.; Corey, L.; Boeckh M. (2003). Rhinovirus infections in hematopoietic stem cell transplant recipients with pneumonia. Clin Infect Dis 36: 1139-43.
  • 7. Jartti, T.; Lehtinen, P.; Vuorinen, T.; Koskenvuo, M.; Ruuskanen, O. (2004).Persistence of rhinovirus and enterovirus RNA after acute respiratory illness in children. J Med Virol 72:695-9.
  • 8. Jartti, T.; Jartti, L.; Peltola, V.; Waris, M.; Ruuskanen, O. (2008). Identification of respiratory viruses in asymptomatic subjects: asymptomatic respiratory viral infections. Pediatr Infect Dis J. Dec;27(12):1103-7. Review.
  • 9. Johnston, S.L.; Sanderson, G.; Pattemore, P.K. (1993). Use of polymerase chain reaction for diagnosis of picornavirus infection in subjects with and without respiratory symptoms. J Clin Microbiol 31:111-117.
  • 10. Kuypers, J.; Campbell, A.P.; Cent, A.; Corey, L.; Boeckh, M. (2009). Comparison of conventional and molecular detection of respiratory viruses in hematopoietic cell transplant recipients. Transpl Infect Dis; 11(4):298-303.
  • 11. Miller, E.K.; Lu, X.; Erdman, D.D.; Poehling, K.A.; Zhu, Y.; Griffin, M.R.; Hartert, T.V.; Anderson, L.J.; Weinberg, G.A.; Hall, C.B.; Iwane, M.K.; Edwards, K.M. New Vaccine Surveillance Network.(2007). Rhinovirus-associated hospitalizations in young children. J Infect Dis Mar 15;195 (6):773-81.
  • 12. Monto, A.S.; Fendrick, A.M.; Sarnes, M.W. (2001).Respiratory illness caused by picornavirus infection: a review of clinical outcomes. Clin Ther Oct; 23 (10):1615-27. Review.
  • 13. Nicholson, K.G.; Kent, J.; Hammersley, V.; Cancio, E. (1996). Risk factors for lower respiratory complications of rhinovirus infections in elderly people living in the community: prospective cohort study. BMJ Nov 2; 313(7065):1119-23.
  • 14. Nokso-Koivisto, J.; Kinnari, T.J.; Lindahl, P.; Hovi, T.; Pitkäranta, A.(2002).Human picornavirus and coronavirus RNA in nasopharynx of children without concurrent respiratory symptoms. J Med Virol. Mar; 66 (3):417-20.
  • 15. Peltola, V.; Waris, M.; Osterback, R.; Susi, P.; Ruuskanen, O.; Hyypia,T. (2008). Rhinovirus transmission within families with children: Insidence of symptomatic and assymptomatic infections. J. Infect. Dis 197: 382-389.
  • 16. Rakes, G.P.; Arruda, E.; Ingram, J.M.; Hoover, G.E.; Zambrano, J.C.; Hayden, F.G.; Platts-Mills, T.A.; Heymann, P.W. (1999). Rhinovirus and respiratory syncytial virus in wheezing children requiring emergency care. IgE and eosinophil analyses. Am J Respir Crit Care Med; 159:785-790.
  • 17. Savolainen, C.; Blomqvist, S.; Mulders, M.N.; Hovi, T. (2002a). Genetic clustering of all 102 human rhinovirus prototype strains: serotype 87 is close to human enterovirus 70. J Gen Virol; 83: 333-340.
  • 18. Savolainen, C.; Mulders, M.N.; Hovi, T. (2002b). Phylogenetic analysis of rhinovirus isolates collected during successive epidemic seasons. Virus Res; 85: 41-46.
  • 19. Singleton, R.J.; Bulkow, L.R.; Miernyk, K.; DeByle, C.; Pruitt, L.; Hummel, K.B.; Bruden, D.; Englund, J.A.; Anderson, L.J.; Lucher, L.; Holman, R.C.; Hennessy, T.W. (2010). Viral respiratory infections in hospitalized and community control children in Alaska. J Med Virol. Jul;82(7):1282-90.
  • 20. van Benten, I.; Koopman, L.; Niesters, B.; Hop, W.; van Middelkoop, B.; de Waal, L.; van Drunen, K.; Osterhaus, A.; Neijens, H.; Fokkens, W.(2003). Predominance of rhinovirus in the nose of symptomatic and asymptomatic infants. Pediatr Allergy Immunol; 14:363-70.
  • 21. van Kraaij, M.G.; van Elden, L.J.; van Loon, A.M.; Hendriksen, K.A.; Laterveer, L.; Dekker, A.W.; Nijhuis, M. (2005).Frequent detection of respiratory viruses in adult recipients of stem cell transplants with the use of real-time polymerase chain reaction, compared with viral culture. Clin Infect Dis. Mar 1;40(5):662-9.
  • 22. van der Zalm ,M.M.; van Ewijk, B.E.; Wilbrink, B.; Uiterwaal, C.S.; Wolfs, T.F.; van der Ent, C.K. (2009). Respiratory pathogens in children with and without respiratory symptoms. J Pediatr.; 154(3):396-400.
  • 23. Wald, T.G.; Shult, P.; Krause, P.; Miller, B.A.; Drinka, P.; Gravenstein, S.(1995). A rhinovirus outbreak among residents of a long-term care facility. Ann Intern Med. Oct 15; 123(8):588-93.
  • *
    Corresponding Author. Mailing address: Rua Pedro de Toledo, 781, andar 15. Vila Clementino, São Paulo-SP, Brazil. ZIP CODE: 04039-032.; Tel/Fax.: +55 (11) 50815394.; E-mail:
  • Publication Dates

    • Publication in this collection
      19 Feb 2013
    • Date of issue
      Dec 2012


    • Received
      02 June 2011
    • Accepted
      07 June 2012
    • Reviewed
      22 Aug 2011
    Sociedade Brasileira de Microbiologia USP - ICB III - Dep. de Microbiologia, Sociedade Brasileira de Microbiologia, Av. Prof. Lineu Prestes, 2415, Cidade Universitária, 05508-900 São Paulo, SP - Brasil, Ramal USP 7979, Tel. / Fax: (55 11) 3813-9647 ou 3037-7095 - São Paulo - SP - Brazil