Outbreak of chikungunya virus in a vulnerable population of Sergipe, Brazil-A molecular and serological survey.

BACKGROUND: Chikungunya virus (CHIKV) is a re-emerging arbovirus that is causing outbreaks in several countries of the Americas. The virus was introduced in Brazil in 2014, and since then, several Brazilian states have notified autochthonous cases. OBJECTIVES: Provide additional evidence on a CHIKV outbreak and an outline of the laboratory and clinical profile of symptomatic patients in Sergipe, Brazil. STUDY DESIGN: In February 2016, we collected 142 serum samples from symptomatic patients for arboviruses in Sergipe, Brazil. All samples were submitted to qRT-PCR for the emerging arboviruses circulating in Brazil - ZIKV, CHIKV, and DENV - and later submitted to the immunoenzymatic assay. RNA positive samples were randomly selected and sequenced for characterization of the genotype involved in the outbreak. RESULTS: Our study had 75.35% (107/142) positivity for CHIKV infection, with all age groups and genera being equally infected. The virus was identified in 11 of the 13 cities studied in that state, including the ECSA genotype. Importantly, fever was the only statistically significant symptoms for CHIKV infection (p<0.05), while asthenia was significantly associated with symptomatic patients that were CHIKV-negative (p<0.05). CONCLUSIONS: Our findings support the importance of fever as a clinical marker and contribute to molecular and serological surveillance data, which may help in the understanding of CHIKV circulation, emergence and clinical description.