1253. The role of dengue viruses serotypes emergence and re-emergence in Rio de Janeiro, Brazil, 2010-2012
Session: Oral Abstract Session: Laboratory and Clinical Virology
Saturday, October 5, 2013: 11:15 AM
Room: The Moscone Center: 300
Background: The state of Rio de Janeiro has been of great epidemiological importance for introduction and spread of dengue viruses (DENV) and over the last 27 years, was marked by extensive epidemics. The existence of a continuous program of virological surveillance aims to detect and monitor the circulation of DENV serotypes in the state, where DENV-1, DENV-2, DENV-3 and DENV-4 co-circulate. To describe the epidemiological, laboratory and clinical aspects of dengue cases occurred in the State of Rio de Janeiro, Brazil due to the emergence and re-emergence of the different dengue serotypes.

Methods: Dengue suspected cases (n=2,833) including 190 fatal cases received at the Flavivirus Laboratory, IOC/FIOCRUZ, Brazil, from January 2010 to December 2012 were analyzed. The MAC-ELISA was carried out for cases confirmation using an IgM capture ELISA. The IgG—ELISA (Miagostovich et al., 1999).The RT—PCR was performed as described by Lanciotti et al., 1992 and the Platelia™ Dengue NS1 Ag-ELISA kit was used for NS1 capture. 

Results: A total of 1,323 cases (47.5%) were confirmed. The MAC-ELISA confirmed 32.6% (376/1,153) of the cases, the RT-PCR confirmed 56.3% (1,022/1,814), 33.1% of 1,569 sera inoculated into C6/36 cells were isolated and NS1 antigen capture confirmed 27.5% (547/1,989) of the cases tested. DENV-2 was the prevalent serotype in 2010, while during 2011 the prevalent serotype was DENV-1. In 2012 the introduction of DENV-4 was detected. Our analysis has shown that patients with secondary infection had a higher risk of presenting a more severe form of the disease (OR = 0,13/95%IC = 0,03-0,43/p <0,001). Furthermore, severe forms were more frequent on children 15 years old and under, and infected by DENV-2 (OR = 1,8 / 95%CI = 0,10-1,22 / p <0,05). From the total of the fatal cases confirmed (n = 67), 60% were due to secondary infections and were more frequent in children 15 years old and under. The DENV-2 serotype was responsible for 42.8% of deaths in 2010, DENV-1 was identified in 71.47% of cases occurred in 2011 and in 2012, DENV-4 was responsible for 25% of deaths confirmed. 

Conclusion: The re-emergence of DENV-2 resulted in the occurrence of severe and fatal cases in younger ages and secondary infections were associated with a more severe disease. However, DENV-1 re-emergence led to fatal cases in 2010. The introduction of DENV-4 in 2011 resulted in an explosive epidemic in 2012.

Manoela Da Silva, Rita Nogueira, Ana Maria De Filippis, Monique Lima, Eliane Araujo, Jaqueline Simoes, Simone Sampaio, Priscila Nunes, Bianca Gonçalves, Carla Sousa, Dinair Lima and Flavia Santos, PhD, Flavivirus Laboratory, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil

Disclosures:

M. Da Silva, None

R. Nogueira, None

A. M. De Filippis, None

M. Lima, None

E. Araujo, None

J. Simoes, None

S. Sampaio, None

P. Nunes, None

B. Gonçalves, None

C. Sousa, None

D. Lima, None

F. Santos, None

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