Author(s)

Gordana Mlinaric-Galinovic, Dubravko Forcic, Jelena Ivancic-Jelecki, Gordana Vojnovic, Jadranka Bozikov, Robert C. Welliver

Department of Medical Statistics, Epidemiology and Medical Informatics, A. Stampar School of Public Health, Medical School University of Zagreb, Zagreb, Croatia.
Department of Virology, Croatian National Institute of Public Health and University Medical School of Zagreb, Zagreb, Croatia.
Department of Virology, Croatian National Institute of Public Health, Zagreb, Croatia.
Division of Infectious Diseases, Department of Pediatrics, Children’s Hospital, Oklahoma University Health Sciences Center, Oklahoma City, USA.
Institute of Immunology Zagreb, Zagreb, Croatia.

Objective: The biennial epidemic pattern of respiratory syncytial virus (RSV) circulation in Croatia has been preserved and could not be related to climatic factors and the predominant RSV subtypes. The possibility that the circulation of different RSV genotypes affect the outbreak cycle in children in Croatia (Zagreb region) over a period of 3 consecutive years was explored in the paper. Methods: The study group consisted of inpatients, aged 0-10 years, who were hospi- talized with acute respiratory tract infections caused by RSV, in Zagreb, over the period from 1 January 2006 to 31 De- cember 2008. The virus was identified in the nasopharyngeal secretion using direct immunofluorescence method. The virus subtype and genotype was determined by real-time PCR and sequence analysis, respectively. Results: RSV infec- tions identified in 731 children. RSV subtype A caused 399 infections, and subtype B 332. Two subtype A genotypes (NA1 and GA5) and three subtype B genotypes (BA7, BA9 and BA10) were found. During persistent RSV biennial cycles namely four succeeding outbreaks, the new genotype from the previous smaller outbreak persevered into the up- coming larger outbreak. Conclusion: Our molecular-epidemiology study of RSV subtypes and genotypes during calen- dar months demonstrates that the biennial RSV cycle cannot be fully explained by the dynamic of the predominant cir- culating genotype of RSV. Other unknown factors account for the biennial cycle of RSV epidemics in Croatia.).

Biennial Cycle; Respiratory Syncytial Virus Types A and B; Genotypes

G. Mlinaric-Galinovic, D. Forcic, J. Ivancic-Jelecki, G. Vojnovic, J. Bozikov and R. Welliver, "Do Circulating RSV-Genotypes Affect Established Biennial Epidemic Periodicity in Zagreb Region?," Open Journal of Respiratory Diseases, Vol. 2 No. 4, 2012, pp. 91-94. doi: 10.4236/ojrd.2012.24013.