CLINICAL AND MOLECULAR SURVEILLANCE OF ARBOVIRAL DISEASES IN SALVADOR-BA: EVIDENCE OF DENGUE, CHIKUNGUNYA, AND OROPOUCHE CIRCULATION

Résumé fourni par la source

Arboviral diseases constitute a group of febrile infectious illnesses with high incidence in tropical regions, characterized by a similar clinical picture, with manifestations such as fever, myalgia, arthralgia, and headache, which often makes differential diagnosis difficult. Among the main diseases, dengue stands out, endemic in Brazil for decades; chikungunya fever, with potential chronicity of joint manifestations; and more recently Oropouche fever, whose occurrence expanded beyond the North region of the country, with records in other localities in 2024. The objective of this study was to conduct surveillance of arboviral cases in an emergency care unit (UPA) in Salvador-BA, characterizing the clinical and epidemiological profile of suspected cases, and identifying etiology through serological and molecular diagnosis. Cross-sectional study from 2023 to 2024 with participants presenting recent fever (≤7 days) and at least two symptoms with rash, myalgia, arthralgia, retro-ocular pain, or headache. Participants were recruited at a UPA, with consent, with blood collection and clinical and sociodemographic data. Tests were performed for dengue, zika, and chikungunya by ELISA serology (IgM and NS1) and molecular methods (multiplex ZDC RT-qPCR and in-house RT-qPCR for Oropouche). Data were analyzed and managed using REDCap. A total of 342 participants were included, with 317 serum samples collected. Age ranged from 3 to 85 years (median 29 years); 39% self-identified as Black, 49% as mixed race, and 13% as White; 61% were women. Cases were included in all months of the study, with peaks in July/23 and in the first quarter of 2024. Reported symptoms included fever (98%), headache (94%), retro-orbital pain (69%), skin rash (38%), arthralgia (81%), myalgia (89%), abdominal pain (45%), epistaxis in 10 (3.0%), gingival bleeding (9%), and hematemesis in 10 (3.0%). Of the samples, 125 (36.5%) tested positive for an arbovirus: 70.0% dengue (NS1: 66; IgM: 43; PCR: 24), 24% chikungunya (IgM: 30; PCR: 10), and 6.0% Oropouche (PCR: 11). The findings reinforce the importance of epidemiological surveillance in the context of active circulation of dengue and chikungunya and early detection of Oropouche in Salvador. The need for continuous monitoring, risk mapping, and preventive actions to avoid outbreaks and worsening is highlighted.

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