Although individuals with Zika virus (ZIKV) antibodies were reported in Malaya in mid-1950s, entomological and human surveillance in Singapore did not identify autochthonous transmission until the outbreak of August-November, 2016. A total of 455 cases from 15 separate clusters were identified. We asked if this ZIKV outbreak increased the incidence of Guillain-Barré syndrome (GBS) and aimed to characterize these cases. Eleven GBS cases, consecutively enrolled into our prospective GBS database from onset to 4 weeks after outbreak, and six controls, comprising three GBS patients enrolled before outbreak and three non-GBS patients, were examined for evidence of recent ZIKV infection. We performed serum, urine ZIKV RT-PCR, ZIKV serology, and virus neutralization assays, accounting for cross-reaction and co-infection with dengue (DENV). We found five GBS cases with only serological evidence of recent ZIKV infection (including one ZIKV-DENV co-infection). A temporal relationship with ZIKV outbreak was unlikely as two cases were GBS controls enrolled 3 months before outbreak. None reported symptoms of ZIKV infection. In addition, compared to last 10 years the national number of GBS hospitalizations did not increase during and immediately after outbreak. We conclude the 2016 Singapore ZIKV outbreak did not cause a change in GBS epidemiology.
Chikungunya fever (CHIKF) is a global infectious disease which can affect a wide range of age groups. The pathological and immunological response upon Chikungunya virus (CHIKV) infection have been reported over the last few years. However, the clinical profile and immune response upon CHIKV infection in children remain largely unknown. In this study, we analyzed the clinical and immunological response, focusing on the cytokine/chemokine profile in a CHIKV-infected pediatric cohort from Sarawak, Malaysia. Unique immune mediators triggered upon CHIKV infection were identified through meta-analysis of the immune signatures between this pediatric group and cohorts from previous outbreaks. The data generated from this study revealed that a broad spectrum of cytokines/chemokines is up-regulated in a sub-group of virus-infected children stratified according to their viremic status during hospitalization. Furthermore, different immune mediator profiles (the levels of pro-inflammatory cytokines, chemokines and growth and other factors) were observed between children and adults. This study gives an important insight to understand the immune response of CHIKV infection in children and would aid in the development of better prognostics and clinical management for children.