Aperfeiçoamento Do Diagnóstico Molecular Para Vigilância Das Infecções De Chikv No Estado Da Bahia

Abstract

Since 2014, three arboviruses, Dengue (DENV), Chikungunya (CHIKV) and Zika (ZIKV), co-circulate in Brazil causing large seasonal outbreaks. The clinical presentation of ZIKV, DENV, and CHIKV infections in the acute phase is similar, including fever, myalgia, maculopapular rash, pruritus, arthralgia, and arthritis. However, the clinical course and the risk of complications are quite different, so the differential diagnosis is essential for the best treatment and control of the diseases. Objectives: Create a biorepository and improve the diagnosis of cases of acute CHIKV infection in the state of Bahia. Material and Methods: Cohort study carried out with 230 individuals from two cities in the state of Bahia and one in Ceará with a clinical condition suspected of arbovirus infection in 2016 and 2017. Clinical and epidemiological data were collected through a questionnaire and clinical evaluation at local health posts, the SHERA prediction score was applied during the clinical evaluation. Saliva, blood and urine samples were collected, all samples were tested in RT-qPCR for confirmation of infection, and plasma was tested with IgM ELISA. All monoinfected patients with disease duration <10 days were kept in the study and reevaluated after 12 months. Results: We observed within the cohort that 50% of the patients evolved to chronic arthralgia in the evaluation after 12 months of infection, the most present symptoms were arthralgia, myalgia and headache, approximately 34% of the individuals had oral lesions resulting from the infection. In the molecular evaluation 35.87% were positive for CHIK, 0.45% for DENV, 3.14% for ZIKV, in the serological analysis 54.42% were positive for CHIKV, 7.55% for ZIKV and 4.19% for DENV. The sample with the best performance for molecular detection was plasma. There was no significant difference between the PCR kits used. The best time for molecular detection observed was up to the 5th day of disease, and for serology from the 4th day onwards. There was no significant correlation between viral load and IgM index and progression to chronic arthralgia. Conclusions: This work demonstrated the best time for testing, which method has the best performance and the ideal sample to be used for the detection of CHIKV in patients with suspected arbovirus infection. The evolution to chronic conditions was observed in half of the individuals tested, demonstrating the need for differential diagnosis and monitoring by the health system.