Analysis of the arbovirus outbreak in a region of the metropolitan area of Buenos Aires. Identification of the first cases of indigenous circulation of Chikungunya virus

Abstract

The arbovirus outbreak that occurred in region V of the Province of Buenos Aires was characterized, during the period from January 1 to May 20, 2023 (EW 1-20). 781 sera from symptomatic patients were analyzed and the presence of viral RNA was analyzed by real-time PCR for Dengue, Zika and Chikungunya, and IgM serology by ELISA for Dengue and Chikungunya. It is observed for Dengue IgM 276/+102 (37%), Dengue PCR 585/+182 (31%), CHK IgM (until EW 16) 237/+63 (27%) and CHK PCR 589/+110 (27 %). The positivity outbreak in EW13 by PCR was 143/+52 (36.4%) for Dengue, coinciding with the week with the highest percentage of positivity in the samples analyzed. For Chikungunya, in SE13 by PCR, 143/+29 (20.3%) were detected, with SE11 being the one with the highest percentage of positivity in the samples analyzed, 44/+19 (43.2%). The Dengue serotypes found correspond to DENV2: 91.7% and DENV1: 8.3%. No positive samples for Zika were detected. The regional epidemiological analysis shows that in San Martín, the highest concentration of cases was in the popular neighborhoods “La Rana” and “9 de Julio” for dengue and chikungunya respectively. The indigenous circulation of Dengue was confirmed with the serotypes DENV1 and DENV2 and Chikungunya, being the first center to warn about the indigenous circulation of the latter virus.