Volume 81, Issue 1
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645


Influenza epidemics occur worldwide annually. The incidence of influenza shows a seasonal pattern in temperate areas, but little is known about influenza seasonality in tropical regions. The objective of this study was to determine the prevalence and the seasonal pattern of influenza infections in children living in the city of Fortaleza in northeastern Brazil. An indirect immunofluorescence assay was performed on nasopharyngeal aspirates collected from children attending in ambulatories, emergency rooms, and wards of the Hospital Infantil Albert Sabin with suspicion of acute respiratory infection during 7 consecutive years (2001–2007). Influenza viruses were detected in 6.3% (234/3,708) of specimens. Laboratory-based surveillance data showed a clear annual epidemic cycle of influenza, with a peak usually occurring in the rainy periods. In Fortaleza, flu infections occurred at a low level throughout the year but exhibit a marked seasonal increase during the rainy season.


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  1. Shek LP, Lee BW, 2003. Epidemiology and seasonality of respiratory tract infections in the tropics. Paediatr Respir Rev 4 : 104–111. [Google Scholar]
  2. Beckett CG, Hosasih H, Ma’roef C, Listiyonengsih E, Elyazar IRF, Wuryadi S, Yuwone D, McArdle JL, Corwin AL, Porter KR, 2004. Influenza surveillance in Indonesia: 1999–2003. Clin Infect Dis 39 : 443–449. [Google Scholar]
  3. Chow A, Ma S, Ling AE, Chew SK, 2006. Influenza-associated deaths in tropical Singapore. Emerg Infect Dis 12 : 114–121. [Google Scholar]
  4. Doraisingham S, Goh KT, Ling AE, Yu M, 1988. Influenza surveillance in Singapore: 1972–86. Bull World Health Organ 66 : 57–63. [Google Scholar]
  5. Dosseh A, Ndiaye K, Spiegel A, Sagna M, Mathiot C, 2000. Epidemiological and virological influenza survey in Dakar, Senegal: 1996–1998. Am J Trop Med Hyg 62 : 639–641. [Google Scholar]
  6. Nguyen HLK, Saito R, Ngiem HK, Nishikawa M, Shobugawa Y, Nguyen DC, Hoang LT, Huynh LP, Suzuki H, 2007. Epidemiology of influenza in Hanoi, Vietman, from 2001 to 2003. J Infect 55 : 58–63. [Google Scholar]
  7. Rao BL, Banerjee K, 1993. Influenza surveillance in Pune, India. Bull World Health Organ 71 : 177–181. [Google Scholar]
  8. Tsai HP, Kuo PH, Liu CC, Wang JR, 2001. Respiratory viral infections among inpatients and outpatients in Taiwan from 1997 to 1999. J Clin Microbiol 39 : 111–118. [Google Scholar]
  9. Arruda E, Hayden FG, McAuliffe JF, de Sousa MA, Mota SB, McAuliffe MI, Geist FC, Carvalho EP, Fernandez MC, Guerrant RL, Gwaltney JM Jr, 1991. Acute respiratory viral infections in ambulatory children of urban northeast Brazil. J Infect Dis 164 : 252–258. [Google Scholar]
  10. Belley N, Carraro E, Perosa A, Granato C, 2007. Patterns of influenza infections among different risk groups in Brazil. Braz J Infect Dis 11 : 399–402. [Google Scholar]
  11. Costa LF, Yorosawa J, Mantese OC, Oliveira TFM, Silveira HL, Nepomuceno LL, Moreira LS, Dyinosio G, Rossi LMG, Oliveira RC, Ribeiro LZG, Queiroz DAO, 2006. Respiratory viruses in children younger than five years old with acute respiratory disease from 2001 to 2004 in Uberlândia, MG, Brazil. Mem Inst Oswaldo Cruz 101 : 301–306. [Google Scholar]
  12. Cruz MEM, Zaidan AME, Rodrigues MML, Sá JPO, Silva NM, Oliveira JF, 1999. Incidence of influenza A and B viruses among the population of Maceió-Al, Brazil. Rev Bras Anal Clin 31 : 9–11. [Google Scholar]
  13. Moura FEA, Borges LC, Souza LSF, Ribeiro DH, Siqueira MM, Ramos EAG, 2003. Estudo de infecções respiratórias agudas virais em crianças atendidas em um centro pediátrico em Salvador (BA). J Bras de Patol Med Laboratorial 39 : 275–282. [Google Scholar]
  14. Oliveira JF, de Sá JPO, Cruz MEM, 2004. Influenza virus A and B identification and monitoring in the population of Maceió. Cien Saude Colet 9 : 241–246. [Google Scholar]
  15. Vidal LR, Siqueira MM, Nogueira MB, Raboni SM, Pereira LA, Takahashi GR, Rotta I, Debur M do C, Dalla-Costa LM, 2008. The epidemiology and antigenic characterization of influenza viruses isolated in Curitiba, South Brazil. Mem Inst Oswaldo Cruz 103 : 180–185. [Google Scholar]
  16. Tsuchiya LR, Costa LM, Raboni SM, Nogueira MB, Pereira LA, Rotta I, Takahashi GR, Coelho M, Siqueira MM, 2005. Viral respiratory infection in Curitiba, Southern Brazil. J Infection 51 : 401–407. [Google Scholar]
  17. Moura FEA, Nunes IF, Junior GBS, Siquiera MM, 2006. Respiratory syncytial virus infections in Northeastern Brazil: seasonal trends and general aspects. Am J Trop Med Hyg 74 : 165–167. [Google Scholar]
  18. Fé MM, Monteiro AJ, Moura FE, 2008. Parainfluenza virus infections in a tropical city: clinical and epidemiological aspects. Braz J Infect Dis 12 : 192–197. [Google Scholar]
  19. Viboud C, Boëlle PY, Pakdaman K, Carrat F, Valleron AI, Flahaut A, 2004. Influenza epidemics in the United States, France, and Australia, 1972–1997. Emerg Infect Dis 10 : 32–39. [Google Scholar]
  20. Alonso WJ, Viboud C, Simonsen L, Hirano EW, Daufenbach LZ, Miller MA, 2007. Seasonality of influenza in Brazil: a traviling wave from the Amazon to the Subtropics. Am J Epidemiol 165 : 1434–1442. [Google Scholar]
  21. Cannell JJ, Zasloff M, Garland CF, Scragg R, Giovannucci E, 2008. On the epidemiology of influenza. Virol J 5 : 29–40. [Google Scholar]
  22. Cannell JJ, Vieth R, Umhau JC, Holick MF, Grant WR, Madronich S, Garland CF, Giovannucci E, 2006. Epidemic influenza and vitamin D. Epidemiol Infect 134 : 1129–1140. [Google Scholar]
  23. Hirani V, Primatesta P, 2005. Vitamin D concentrations among people aged 65 years and over living in private households and institutions in England: population survey. Age Ageing 34 : 485–491. [Google Scholar]
  24. Weeb AR, Kline L, Holick MF, 1988. Influence of season and latitude on the cutaneous synthesis of vitamin D3: exposure to winter sunlight in Boston and Edmonton will not promote vitamin D3 in human skin. J Clin Endocrinol Metab 67 : 373–378. [Google Scholar]

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  • Received : 15 Sep 2008
  • Accepted : 29 Jan 2009

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