Estudio de Seroprevalencia de anticuerpos IgG anti virus Dengue en la ciudad de Córdoba.

BORDA M; BARBÁS G; BLANCO S; FREGA L; CASTRO G; GALLEGO S; FABRI C; LUPPO V; MORALES A; KADEMIÁN S; ALMADA S; CANNA F; DE LEÓN J; CUDOLÁ A

Simposio; 2010- XIII Simposio Internacional sobre Control Epidemiológico de Enfermedades Transmitidas por Vectores y I Encuentro Nacional sobre Enfermedades Olvidadas.; 2010

Introduction: Between January and May 2009, an outbreak of Dengue (serotype 1) was declared in Argentina. On April 2009 it was demonstrated that DEN-1 virus circulated in Cordoba, being the first epidemic that broke out in our region. The aim of the present study was determine DEN-1 seroprevalence in Cordoba city, in order to design prevention strategies for future outbreaks and provide important information to local health authorities. Materials and Methods: A total of 800 samples derived to the Central Laboratory from public health centers located in Cordoba city were studied. Samples corresponded to healthy blood donors, pregnant women and patients who required medical assistance. The number of studied samples was determined based on a 95% confidence interval and an estimated prevalence of 0.5%. This study was designed as a non-associated anonymous survey. The IgG anti-Dengue was detected by ELISA (PanBio Diagnostics). Reactive samples and 10% of non-reactive ones were sent to the National Reference Centre to confirm DEN-1 virus positivity by 90% plaque reduction neutralization assay. To evaluate cross-reactivity among Flavivirus, samples were also studied for St. Louis (SLE) and West Nile (WN) virus. Results: Out of 800 samples studied, 36 (4.5%) were reactive for IgG anti-Dengue, whereas 760 (95 %) were non-reactive and 4 (0.5%) could not be defined (reactive non-conclusive). All 36 reactive samples by ELISA were studied by the neutralization assay, resulting 4 (11.4%) positive for DEN-1, 26 (74.3%) positive for SLE, 2 (5.7 %) positive for WN and 4 (11.1%) negative. The 4 samples that were non-conclusive by ELISA resulted positive for SLE by neutralization and non-reactive samples for IgG anti-Dengue resulted negative for DEN-1 neutralizing antibodies.  Conclusions: Population serological surveys conducted in inter-epidemic periods provide an estimate of the true incidence of the infection caused by Dengue. In this study, specific neutralizing antibodies for DEN-1 were detected in 0.5% (4/800) of the studied samples. The diagnostic strategy employed highlights the importance to discard serological cross-reactions among Flavivirus.