Detection of dengue virus

Risk of Uveitis in Dengue Fever Patients: A Population-Based Cohort Study in Taiwan

Dengue-related ocular complications were considered rare, but recent evidence points to a broader spectrum of manifestations, including uveitis. This study utilized the Taiwan National Health Insurance Research Database (NHIRD) to investigate the incidence of uveitis in dengue patients, aiming to fill this research gap. This population-based, retrospective cohort study utilized the Taiwan National Health Insurance Research Database (NHIRD) and included patients with and without Dengue fever. The non-Dengue fever cohort comprised randomly selected control patients who were matched. Hazard ratios and Kaplan-Meier analysis were conducted to compare the incidence of uveitis in the Dengue and non-Dengue cohorts. Subgroup analyses were carried out based on age groups, genders, and comorbidities. A total of 26 950 patients diagnosed with Dengue fever were included in the study (49.6% female, mean age at index 41.63 years). Based on a 1:4 matching ratio, 107 800 control subjects without uveitis (50.03% female, mean age at index 41.41 years) were also included. The adjusted hazard ratio (aHR) of uveitis was higher in the Dengue fever group than in the non-Dengue fever group (aHR = 1.38, p < 0.001). A history of stroke or transient ischemic attack (TIA) was not associated with uveitis. Stratified analyses revealed that patients with Dengue fever had an increased risk regardless of their sex and age. The Kaplan-Meier method with the log-rank test showed a significantly higher cumulative incidence of uveitis in the Dengue fever cohort than in the non-Dengue fever cohort (p < 0.001). In the subgroup analysis for most major comorbidities, the significantly higher risk for uveitis in those patients with Dengue fever, was only demonstrated in the subgroups of those without these major comorbidities. Our findings showed Dengue infection to be associated with increased risk for uveitis. Clinicians should be attentive to a history of stroke or TIA in patients with Dengue fever.

Viral Sepsis

Viruses are the smallest infective agents currently known to affect humans and animals. The virus has a centrally situated nucleic acid, which is encased within a capsid consisting of a protein core. Viruses are obligatory intracellular microorganisms that live inside cells, using components of the nucleic acid and protein generating system of the host to replicate and trigger cell destruction leading to diseases. Alternatively, the host’s defense mechanisms lead to cell destruction in an attempt to clear cells infected by the viruses. The nucleic acid is RNA or DNA, which may be single-stranded or double-stranded [1]. The pathophysiology of viral infections may be attributed to the degeneration and cellular necrosis of the infected cells, leading to local and systemic inflammatory responses. The body’s defense mechanisms include phagocytosis, humoral and cell-mediated responses and the production of interferons [2]. Interferons prevent the local spread of viruses, whereas antibodies prevent viremia, ensure long-term immunity and sensitize infected cells to be destroyed by T-cells and macrophages [3, 4]. Cell-mediated immunity leads to an increase in cytotoxic cells that then release lymphokines, including interferon.

A novel dengue virus detection method that couples DNAzyme and gold nanoparticle approaches

Background

Recent epidemics of dengue viruses (DENV) coupled with new outbreaks on the horizon have renewed the demand for novel detection methods that have the ability to identify this viral pathogen prior to the manifestation of symptoms. The ability to detect DENV in a timely manner is essential for rapid recovery from disease symptoms. A modified lab-derived 10-23 DNAzyme tethered to gold nanoparticles provides a powerful tool for the detection of viruses, such as DENV.

Results

We examined the effectiveness of coupling DNAzyme (DDZ) activation to the salt-induced aggregation of gold nanoparticles (AuNP) to detect dengue virus (DENV) progeny in mosquito cells. A DNAzyme was designed to recognize the 5’ cyclization sequence (5’ CS) that is conserved among all DENV, and conjugated to AuNPs. DDZ-AuNP has demonstrated the ability to detect the genomic RNA of our model dengue strain, DENV-2 NGC, isolated from infected Aedes albopictus C6/36 cells. These targeting events lead to the rapid aggregation of AuNPs, resulting in a red to clear color transition of the reaction mixes, and thus positive detection of the DENV RNA genome. The inclusion of SDS in the reaction mixture permitted the detection of DENV directly from cell culture supernatants without additional sample processing. Specificity assays demonstrated detection is DENV-specific, while sensitivity assays confirm detection at levels of 1 × 10¹ TCID50 units. These results demonstrate DDZ-AuNP effectively detects DENV genomes in a sequence specific manner and at concentrations that are practical for field use.

Conclusions

We have developed an effective detection assay using DNAzyme catalysis coupled with AuNP aggregation for the detection of DENV genomes in a sequence specific manner. Full development of our novel DDZ-AuNP detection method will provide a practical, rapid, and low cost alternative for the detection of DENV in mosquito cells and tissues, and possibly infected patient serum, in a matter of minutes with little to no specialized training required.

Diagnosis of dengue: an update

Early diagnosis of dengue, the most common mosquito-borne disease globally, remains challenging. Dengue presents initially as undifferentiated fever, with symptoms becoming more pathognomonic in the later stages of illness. This limits the timeliness in the delivery of appropriate supportive interventions. Laboratory tests are useful for diagnosis although the short-lived viremia and the presence of secondary infection with one of the four heterologous viral serotypes collectively complicate the choice and interpretation of laboratory tests. In this article, the authors review the various approaches for diagnosis of dengue and discuss the appropriate tests to use, including when a dengue vaccine, which is in the late stages of development, is licensed for use. The ensuing reduced dengue prevalence could make diagnosis for vaccine efficacy and escape-mutant monitoring even more challenging.