Production and Characterization of Two Specific ZIKV Antigens Based on Bioinformatic Analysis and Serological Screening.

BACKGROUND: The high structural similarity between the Zika virus (ZIKV) and other flaviviruses, such as Dengue Virus (DENV), complicates the identification of the infecting virus due to the occurrence of cross-reactions in serological assays. This phenomenon has increased the demand for more specific antigens for immunodiagnostic applications. METHODS: The present work aimed to identify specific regions of ZIKV and produce unique antigens through computational methods, molecular and microbiological techniques. RESULTS: Based on the computational analysis we successfully expressed two recombinant proteins derived from specific regions of the ZIKV. Through serological assays using characterized sera, we observed that the region 146-182 of ZIKV's E protein, expressed in tandem, was not reactive despite the predictive sensitivity and specificity observed by computer analyses. On the other hand, the non-denatured fraction 220-352 of ZIKV's NS1 showed greater specificity to IgG+ sera of ZIKV by dot blot and western blot, which highlights its properties as a possible tool in the diagnosis of ZIKV. CONCLUSION: These findings demonstrate that ZIKV NS1 fraction 220-352 is a potential tool that may be applied in the development of serological diagnosis. We also provided data that suggest the non-applicability of the region 146-182 of ZIKV's protein E in serological assays despite previous indications about its potential based on computational analysis.

Meningoencephalitis Associated with Zika Virus and Chikungunya Virus Infection.

The etiology of viral meningoencephalitis is frequently unidentified. Chikungunya virus (CHIKV) and Zika virus (ZIKV) are known to affect the central nervous system and should therefore be considered in the diagnosis of meningoencephalitis, as its outcome may be influenced by the etiologic agent, age, and immunological condition of the patient. In this study, we aimed to determine whether CHIKV and ZIKV were the etiological agents of viral encephalitis in patients with meningoencephalitis admitted to the main hospital of infectious diseases in the city of Salvador, Brazil. Of the 1,049 patients with neurological symptoms who were admitted to the hospital during the study period, 149 were enrolled and 20 (13.34%) tested positive for ZIKV (12%) or CHIKV (1.34%). No specific clinical manifestations were observed to be associated with ZIKV or CHIKV infections. Determination of the etiological agent of meningitis and encephalitis is important for patient management and appropriate treatment.

New Challenge for Zika Virus Infection: Human Reservoirs?

Zika virus (ZIKV) is considered to cause an acute self-limited infection in adults, and microcephaly in fetus. Presence of the virus for long periods has been detected in body fluids; however, persistent viremia in serum for more than 1 year has not yet been reported. We have investigated persistence of ZIKV in serum samples of 77 subjects who were infected by the virus between 18 months and 3 years before the start of this study. The subjects included children with microcephaly and their parents. Serum samples were subjected to routine RT-qPCR assay for ZIKV, Chikungunya virus, and Dengue virus. From the 77 subjects, five showed positive for the presence of ZIKV particles by RT-qPCR, including four members of the same family. Viral isolation in Vero cells and C6/36 cells confirmed the result and showed the viral particles were active. We have detected viremia in healthy carriers up to 3 years after symptom onset. Humans acting as potential viral reservoirs have major implication for the current understanding of ZIKV infection.