Dengue and chikungunya infection in neurologic disorders from endemic areas in Brazil

OBJECTIVE: To detect the frequency of dengue virus (DENV), Chikungunya virus (CHIKV), and Zika virus (ZIKV) in adult patients with suspected viral infection of the CNS or postinfectious syndromes living in the state of Rio de Janeiro, Brazil. METHODS: DENV, CHIKV, and ZIKV RNA by reverse transcription PCR (RT-PCR) and specific IgM antibodies were investigated in 47 CSF and serum samples of 36 adult patients suspected with viral infection or postinfectious neurologic diseases. In addition, intrathecal synthesis of anti-DENV and anti-CHIKV IgG antibodies was also evaluated using a specific antibody index. RESULTS: Of the total group, neuroinvasive arbovirus was confirmed in 31% (11/36) of the cases: 6 (55%) by RT-PCR in CSF and/or serum, 1 (9%) by RT-PCR in CSF and/or serum and specific IgM in CSF, and 4 (36%) by specific IgM in CSF. Five cases had DENV infection, and 6 patients were positive for CHIKV. No sample amplified for ZIKV. In addition, 3 of 7 (42%) tested cases had intrathecal synthesis of DENV or CHIKV antibodies. The neurologic complications included encephalitis (7), Guillain-Barré syndrome (2), optic neuritis (1), neuromyelitis optica spectrum disorder (1), polyneuropathy, (1) and myelitis (1). CONCLUSION: DENV and CHIKV are a frequent cause of emerging and reemerging infections. It increases the number of cases with neurologic complications worldwide. We demonstrated that the combined use of molecular and immunologic tests in CSF/serum might support more widely the diagnosis of neurologic disorders caused by arbovirus in endemic areas. The detection of intrathecal synthesis of specific IgG antibodies may be promising for the retrospective diagnosis of neuroinvasive disorders caused by arbovirus.