Objective: To evaluate the oscillations on the viral detection in adenotonsillar tissues from patients with chronic adenotonsillar diseases as an indicia of the presence of persistent viral infections or acute subclinical infections. Study design: Cross-sectional prospective study. Setting: Tertiary hospital. Methods: The fluctuations of respiratory virus detection were compared to the major climatic variables during a two-year period using adenoids and palatine tonsils from 172 children with adenotonsillar hypertrophy and clinical evidence of obstructive sleep apnoea syndrome or recurrent adenotonsillitis, without symptoms of acute respiratory infection (ARI), by TaqMan real-time PCR. Results: The rate of detection of at least one respiratory virus in adenotonsillar tissue was 87%. The most frequently detected viruses were human adenovirus in 52.8%, human enterovirus in 47.2%, human rhinovirus in 33.8%, human bocavirus in 31.1%, human metapneumovirus in 18.3% and human respiratory syncytial virus in 17.2%. Although increased detection of human enterovirus occurred in summer/autumn months, and there were summer nadirs of human respiratory syncytial virus in both years of the study, there was no obvious viral seasonality in contrast to reports with ARI patients in many regions of the world. Conclusion: Respiratory viruses are continuously highly detected during whole year, and without any clinical symptomatology, indicating that viral genome of some virus can persist in lymphoepithelial tissues of the upper respiratory tract.781016551661Tregoning, J.S., Schwarze, J., Respiratory viral infections in infants: causes, clinical symptoms, virology, and immunology (2010) Clin. Microbiol. Rev., 23, pp. 74-98Leupe, P., Hox, V., Debruyne, F., Schrooten, W., Claes, N.V., Lemkens, N., Tonsillectomy compared to acute tonsillitis in children: a comparison study of societal costs (2012) B-ENT, 8, pp. 103-111Proenca-Modena, J.L., Pereira Valera, F.C., Jacob, M.G., Buzatto, G.P., Saturno, T.H., Lopes, L., High rates of detection of respiratory viruses in tonsillar tissues from children with chronic adenotonsillar disease (2012) PLoS ONE, 7, p. e42136Suvilehto, J., Roivainen, M., Seppanen, M., Meri, S., Hovi, T., Carpen, O., Rhinovirus/enterovirus RNA in tonsillar tissue of children with tonsillar disease (2006) J. Clin. Virol., 35, pp. 292-297Szalmas, A., Papp, Z., Csomor, P., Konya, J., Sziklai, I., Szekanecz, Z., Microbiological profile of adenoid hypertrophy correlates to clinical diagnosis in children (2013) Biomed. Res. Int., 2013, p. 629607Balbani, A.P., Weber, S.A., Montovani, J.C., Update in obstructive sleep apnea syndrome in children (2005) Braz. J. Otorhinolaryngol., 71, pp. 74-80Duman, D., Naiboglu, B., Esen, H.S., Toros, S.Z., Demirtunc, R., Impaired right ventricular function in adenotonsillar hypertrophy (2008) Int. J. Cardiovasc. Imaging, 24, pp. 261-267Papaioannou, G., Kambas, I., Tsaoussoglou, M., Panaghiotopoulou-Gartagani, P., Chrousos, G., Kaditis, A.G., Age-dependent changes in the size of adenotonsillar tissue in childhood: implications for sleep-disordered breathing (2012) J. Pediatr.Erdag, T.K., Ecevit, M.C., Guneri, E.A., Dogan, E., Ikiz, A.O., Sutay, S., Pathologic evaluation of routine tonsillectomy and adenoidectomy specimens in the pediatric population: is it really necessary? (2005) Int. J. Pediatr. Otorhinolaryngol., 69, pp. 1321-1325Diaz, R.R., Picciafuoco, S., Paraje, M.G., Villegas, N.A., Miranda, J.A., Albesa, I., Relevance of biofilms in pediatric tonsillar disease (2011) Eur. J. Clin. Microbiol. Infect. Dis., 30, pp. 1503-1509Sadeghi-Shabestari, M., Jabbari Moghaddam, Y., Ghaharri, H., Is there any correlation between allergy and adenotonsillar tissue hypertrophy? (2011) Int. J. Pediatr. Otorhinolaryngol., 75, pp. 589-591Sloan, C., Moore, M.L., Hartert, T., Impact of pollution, climate, and sociodemographic factors on spatiotemporal dynamics of seasonal respiratory viruses (2011) Clin. Transl. Sci., 4, pp. 48-54Tang, J.W., Loh, T.P., Correlations between climate factors and incidence - a contributor to RSV seasonality (2014) Rev. Med. Virol., 24, pp. 15-34Shek, L.P., Lee, B.W., Epidemiology and seasonality of respiratory tract virus infections in the tropics (2003) Paediatr. Respir. Rev., 4, pp. 105-111Bellei, N., Carraro, E., Perosa, A., Watanabe, A., Arruda, E., Granato, C., Acute respiratory infection and influenza-like illness viral etiologies in Brazilian adults (2008) J. Med. Virol., 80, pp. 1824-1827Cintra, O.A., Owa, M.A., Machado, A.A., Cervi, M.C., Figueiredo, L.T., Rocha, G.M., Occurrence and severity of infections caused by subgroup A and B respiratory syncytial virus in children in southeast Brazil (2001) J. Med. Virol., 65, pp. 408-412Straliotto, S.M., Siqueira, M.M., Muller, R.L., Fischer, G.B., Cunha, M.L., Nestor, S.M., Viral etiology of acute respiratory infections among children in Porto Alegre, RS, Brazil (2002) Rev. Soc. Bras. Med. Trop., 35, pp. 283-291Paradise, J.L., Bluestone, C.D., Bachman, R.Z., Colborn, D.K., Bernard, B.S., Taylor, F.H., Efficacy of tonsillectomy for recurrent throat infection in severely affected children. Results of parallel randomized and nonrandomized clinical trials (1984) N. Engl. J. Med., 310, pp. 674-683Nascimento-Carvalho, C.M., Cardoso, M.R., Barral, A., Araujo-Neto, C.A., Oliveira, J.R., Sobral, L.S., Seasonal patterns of viral and bacterial infections among children hospitalized with community-acquired pneumonia in a tropical region (2010) Scand. J. Infect. Dis., 42, pp. 839-844Haynes, A.K., Manangan, A.P., Iwane, M.K., Sturm-Ramirez, K., Homaira, N., Brooks, W.A., Respiratory syncytial virus circulation in seven countries with Global Disease Detection Regional Centers (2013) J. Infect. Dis., 208, pp. S246-S254Schlaudecker, E.P., Heck, J.P., Macintyre, E.T., Martinez, R., Dodd, C.N., McNeal, M.M., Etiology and seasonality of viral respiratory infections in rural Honduran children (2012) Pediatr. Infect. Dis. J., 31, pp. 1113-1118Bloom-Feshbach, K., Alonso, W.J., Charu, V., Tamerius, J., Simonsen, L., Miller, M.A., Latitudinal variations in seasonal activity of influenza and respiratory syncytial virus (RSV): a global comparative review (2013) PLoS ONE, 8, p. e54445Advani, S., Sengupta, A., Forman, M., Valsamakis, A., Milstone, A.M., Detecting respiratory viruses in asymptomatic children (2012) Pediatr. Infect. Dis. J., 31, pp. 1221-1226Camara, A.A., Silva, J.M., Ferriani, V.P., Tobias, K.R., Macedo, I.S., Padovani, M.A., Risk factors for wheezing in a subtropical environment: role of respiratory viruses and allergen sensitization (2004) J. Allergy Clin. Immunol., 113, pp. 551-557Winther, B., Hayden, F.G., Hendley, J.O., Picornavirus infections in children diagnosed by RT-PCR during longitudinal surveillance with weekly sampling: association with symptomatic illness and effect of season (2006) J. Med. Virol., 78, pp. 644-650Herberhold, S., Eis-Hubinger, A.M., Panning, M., Frequent detection of respiratory viruses by real-time PCR in adenoid samples from asymptomatic children (2009) J. Clin. Microbiol., 47, pp. 2682-2683Sato, M., Li, H., Ikizler, M.R., Werkhaven, J.A., Williams, J.V., Chappell, J.D., Detection of viruses in human adenoid tissues by use of multiplex PCR (2009) J. Clin. Microbiol., 47, pp. 771-773Enders, J.F., Bell, J.A., Dingle, J.H., Francis, T., Hilleman, M.R., Huebner, R.J., Group name proposed for new respiratory-tract viruses (1956) Science, 124, pp. 119-120Garnett, C.T., Talekar, G., Mahr, J.A., Huang, W., Zhang, Y., Ornelles, D.A., Latent species C adenoviruses in human tonsil tissues (2009) J. Virol., 83, pp. 2417-2428Zhang, Y., Huang, W., Ornelles, D.A., Gooding, L.R., Modeling adenovirus latency in human lymphocyte cell lines (2010) J. Virol., 84, pp. 8799-8810Allander, T., Tammi, M.T., Eriksson, M., Bjerkner, A., Tiveljung-Lindell, A., Andersson, B., Cloning of a human parvovirus by molecular screening of respiratory tract samples (2005) Proc. Natl. Acad. Sci. U.S.A., 102, pp. 12891-12896Vicente, D., Cilla, G., Montes, M., Perez-Yarza, E.G., Perez-Trallero, E., Human bocavirus, a respiratory and enteric virus (2007) Emerg. Infect. Dis., 13, pp. 636-637Liu, H., Fu, Y., Xie, J., Cheng, J., Ghabrial, S.A., Li, G., Widespread endogenization of densoviruses and parvoviruses in animal and human genomes (2011) J. Virol., 85, pp. 9863-9876Proenca-Modena, J.L., Gagliardi, T.B., Escremim de Paula, F., Iwamoto, M.A., Criado, M.F., Camara, A.A., Detection of human bocavirus mRNA in respiratory secretions correlates with high viral load and concurrent diarrhea (2011) PLoS ONE, 6, p. e21083Kapoor, A., Hornig, M., Asokan, A., Williams, B., Henriquez, J.A., Lipkin, W.I., Bocavirus episome in infected human tissue contains non-identical termini (2011) PLoS ONE, 6, p. e21362Lusebrink, J., Schildgen, V., Tillmann, R.L., Wittleben, F., Bohmer, A., Muller, A., Detection of head-to-tail DNA sequences of human bocavirus in clinical samples (2011) PLoS ONE, 6, p. e19457Zhao, H., Zhao, L., Sun, Y., Qian, Y., Liu, L., Jia, L., Detection of a bocavirus circular genome in fecal specimens from children with acute diarrhea in Beijing, China (2012) PLoS ONE, 7, p. e48980Khetsuriani, N., Lamonte-Fowlkes, A., Oberst, S., Pallansch, M.A., Enterovirus surveillance - United States, 1970-2005 (2006) MMWR Surveill. Summ., 55, pp. 1-20Jartti, T., Lehtinen, P., Vuorinen, T., Osterback, R., van den Hoogen, B., Osterhaus, A.D., Respiratory picornaviruses and respiratory syncytial virus as causative agents of acute expiratory wheezing in children (2004) Emerg. Infect. Dis., 10, pp. 1095-1101Vidaurreta, S.M., Marcone, D.N., Ellis, A., Ekstrom, J., Cukier, D., Videla, C., Acute viral respiratory infection in children under 5 years: epidemiological study in two centers in Buenos Aires, Argentina (2011) Arch. Argent. Pediatr., 109, pp. 296-304Matthew, J., Pinto Pereira, L.M., Pappas, T.E., Swenson, C.A., Grindle, K.A., Roberg, K.A., Distribution and seasonality of rhinovirus and other respiratory viruses in a cross-section of asthmatic children in Trinidad, West Indies (2009) Ital. J. Pediatr., 35, p. 16Katzov-Eckert, H., Botosso, V.F., Neto, E.A., Zanotto, P.M., Phylodynamics and dispersal of HRSV entails its permanence in the general population in between yearly outbreaks in children (2012) PLoS ONE, 7, p. e41953