Background: Although acute respiratory infections (ARIs) are the global leading cause of pediatric morbidity and mortality, the relative impact of viral pathogens on pediatric ARIs is still poorly understood, especially in equatorial settings. Long-term studies of multiple viruses concurrently circulating in these regions are still lacking. Here, we report the results of a systematic prospective surveillance of multiple respiratory viruses conducted every weekday for nearly a decade in an equatorial city in Brazil.
Methods: We analyzed the relative burden of influenza, parainfluenza, respiratory syncytial virus (RSV), adenovirus, and metapneumovirus, their seasonality, and their association with climatic and demographic factors, ARI diagnosis, and pediatric mortality.
Results and Conclusions: RSV was the primary driver of severe childhood respiratory infections, including pneumonia. RSV was also the virus most strongly associated with respiratory-associated deaths, with RSV circulation and pediatric mortality being in phase. Annual circulation of influenza peaked much earlier than annual mortality due to respiratory causes. The results also show that viral circulation can be strongly seasonal even in equatorial regions, which lack seasons with low temperatures: RSV and influenza were concentrated in the rainy season, whereas parainfluenza predominantly circulated in the dry season. The consistent epidemiologic patterns observed can be used for an effective adjustment of the timing of therapeutic and prophylactic interventions in this and potentially in other equatorial regions.
From the *Fogarty International Center, National Institutes of Health, Bethesda, MD; †Virology Laboratory, Department of Pathology and Medicine, Universidade Federal do Ceará, Ceará, Brazil; and ‡Origem Scientifica, Florianópolis, Brazil.
Accepted for publication September 19, 2011.
Conflicts of interest and sources of funding: M.A.M., supported by the Fogarty International Center, National Institutes of Health; F.E.A.M., supported by Fundação Cearense de Apoio ao Desenvolvimento Científico e Tecnológico (FUNCAP); B.J.L. received a PhD grant from FUNCAP; S.A.R.P., C.M.G.D.F., and E.C.M. received grants from FUNCAP; W.J.A., supported by the Multinational Influenza Seasonal Mortality Study, a project led by the Fogarty International Center (NIH) and funded by the Office of Global Health Affairs' International Influenza Unit (Department of Health and Human Services). The authors have no other funding or conflicts of interest to disclose.
Address for correspondence: Fernanda Edna Araújo Moura, PhD, Faculdade de Medicina, Universidade Federal do Ceara, Rua Coronel Nunes de Melo 1315, CEP 60430270, Fortaleza, Ceara, Brazil. E-mail: firstname.lastname@example.org.