In 2016, we have seen a rapid emergence of Zika virus-associated Guillain-Barré syndrome (GBS) since its first description in a French-Polynesian patient in 2014. Current evidence estimates the incidence of GBS at 24 cases per 100 000 persons infected by Zika virus. This will result in a sharp rise in the number of GBS cases worldwide with the anticipated global spread of Zika virus. A better understanding of the pathogenesis of Zika-associated GBS is crucial to prepare us for the current epidemic. In this review, we evaluate the existing literature on GBS in association with Zika and other flavivirus to better define its clinical subtypes and electrophysiological characteristics, demonstrating a demyelinating subtype of GBS in most cases. We also recommend measures that will help reduce the gaps in knowledge that currently exist.
Zika virus (ZIKV) is an emerging mosquito-borne virus that was first isolated from a sentinel rhesus monkey in the Zika Forest in Uganda in 1947. In Asia, the virus was isolated in Malaysia from Aedes aegypti mosquitoes in 1966, and the first human infections were reported in 1977 in Central Java, Indonesia. In this review, all reported cases of ZIKV infection in Asia as of September 1, 2016 are summarized and some of the hypotheses that could currently explain the apparently low incidence of Zika cases in Asia are explored.
Zika virus (ZIKV) is a mosquito-borne flavivirus distributed throughout much of Africa and Asia. Infection with the virus may cause acute febrile illness that clinically resembles dengue fever. A recent study indicated the existence of three geographically distinct viral lineages; however this analysis utilized only a single viral gene. Although ZIKV has been known to circulate in both Africa and Asia since at least the 1950s, little is known about the genetic relationships between geographically distinct virus strains. Moreover, the geographic origin of the strains responsible for the epidemic that occurred on Yap Island, Federated States of Micronesia in 2007, and a 2010 pediatric case in Cambodia, has not been determined.
In 1977 and 1978 selected in-patients at the Tegalyoso Hospital, Klaten, Indonesia who had recent onsets of acute fever were serologically studied for evidence for alphavirus and flavivirus infections. A brief clinical history was taken and a check list of signs and symptoms was completed on admission. Acute and convalescent phase sera from 30 patients who showed evidence that a flavivirus had caused their illnesses were tested for neutralizing antibodies to several flaviviruses which occur in South-east Asia. Paired sera from seven patients demonstrated a fourfold rise in antibody titre from acute to convalescent phase. The most common clinical manifestations observed in this series of patients included high fever, malaise, stomach ache, dizziness and anorexia. None of the seven patients had headache or rash despite the fact that headache and rash had been associated with two of the three previously studied. The onsets of illness clustered toward the end of the rainy season when populations of Aedes aegypti, a probable vector in Malaysia, were most abundant.
The sharp increase in incidence of dengue infection has necessitated the development of methods for the rapid diagnosis of this deadly disease. Here we report the design and development of a reliable, sensitive, and specific optical immunosensor for the detection of the dengue nonstructural protein 1 (NS1) biomarker in clinical samples obtained during early stages of infection. The present optical NS1 immunosensor comprises a biosensing surface consisting of specific monoclonal NS1 antibody for immunofluorescence-based NS1 antigen determination using fluorescein isothiocyanate (FITC) conjugated to IgG antibody. The linear range of the optical immunosensor was from 15-500ngmL-1, with coefficient of determination (R2) of 0.92, high reproducibility (the relative standard deviation obtained was 2%), good stability for 21days at 4°C, and low detection limit (LOD) at 15ngmL-1. Furthermore, the optical immunosensor was capable of detecting NS1 analytes in plasma specimens from patients infected with the dengue virus, with low cross-reaction with plasma specimens containing the Japanese encephalitis virus (JEV) and Zika virus. No studies have been performed on the reproducibility and cross-reactivity regarding NS1 specificity, which is thus a limitation for optical NS1 immunosensors. In contrast, the present study addressed these limitations carefully where these two important experiments were conducted to showcase the robustness of our newly developed optical-based fluorescence immunosensor, which can be practically used for direct NS1 determination in any untreated clinical sample.