The unexpectedly low vaccine efficacy of Dengvaxia®, developed by Sanofi Pasteur, and a higher risk of severe diseases after vaccination among dengue-naive children or children younger than 6 years old, have cast skepticism about the safety of dengue vaccination resulting in the suspension of school-based immunization programs in the Philippines. The absence of immune correlates of protection from dengue virus (DENV) infection hampers the development of other potential DENV vaccines. While tetravalent live-attenuated tetravalent vaccines (LATVs), which mimic natural infection by inducing both cellular and humoral immune responses, are still currently favored, developing a vaccine that provides a balanced immunity to all four DENV serotypes remains a challenge. With the recently advanced understanding of virion structure and B cell immune responses from naturally infected DENV patients, two points of view in developing a next-generation dengue vaccine emerged: one is to induce potent, type-specific neutralizing antibodies (NtAbs) recognizing quaternary structure-dependent epitopes by having four components of vaccine strains replicate equivalently; the other is to induce protective and broadly NtAbs against the four serotypes of DENV with a universal vaccine. This article reviews the studies related to these issues and the current knowledge gap that needs to be filled in.

Dengue viral (DENV) infection results in a wide spectrum of clinical manifestations from asymptomatic, mild fever to severe hemorrhage diseases upon infection. Severe dengue is the leading cause of pediatric deaths and/or hospitalizations, which are a major public health burden in dengue-endemic or hyperendemic countries. Like other RNA viruses, DENV continues to evolve. Adaptive mutations are obscured by the major consensus sequence (so-called wild-type sequences) and can only be identified once they become the dominant viruses in the virus population, a process that can take months or years. Traditional surveillance systems still rely on Sanger consensus sequencing. However, with the recent advancement of high-throughput next-generation sequencing (NGS) technologies, the genome-wide investigation of virus population within-host and between-hosts becomes achievable. Thus, viral population sequencing by NGS can increase our understanding of the changing epidemiology and evolution of viral genomics at the molecular level. This review focuses on the studies within the recent decade utilizing NGS in different experimental and epidemiological settings to understand how the adaptive evolution of dengue variants shapes the dengue epidemic and disease severity through its transmission. We propose three types of studies that can be pursued in the future to enhance our surveillance for epidemic prediction and better medical management.

Cryptosporidium is increasingly being recognized as an important cause of diarrhea worldwide. Although well known for its impact among HIV positive population, improved diagnostic tests have contributed to its emerging recognition one among the most prevalent causes of early childhood moderate to severe diarrhea, persistent diarrhea, and impaired neurocognitive development. The diagnosis of Cryptosporidiosis is generally carried out based on availability of skilled microscopist or advanced equipment for molecularand immunologic-based assays. As an emerging enteric pathogen of medical importance, the need for point-of-care technology is deemed necessary for early identification of the pathogen and application of infection control measures for its potential risk of creating outbreaks. Current point-of-care technologies demonstrate varying sensitivities and specificities and may already address the present diagnostic need.

Background: Dengue virus (DENV) infection remains a global public health concern. Enzyme-linked immunosorbent assays (ELISAs), which detect antibodies targeting the envelope (E) protein of DENV, serve as the front-line serological test for presumptive dengue diagnosis. Very few studies have determined the serostatus by detecting antibodies targeting the nonstructural protein 1 (NS1), which can function as diagnostic biomarkers to distinguish natural immunity from vaccine-induced immunity. Methods: We used community-acquired human serum specimens, with the serostatus confirmed by focus reduction microneutralization test (FRμNT), to evaluate the diagnostic performances of two NS1-based ELISA methods, namely, immunoglobulin G antibody-capture ELISA (NS1 GAC–ELISA) and indirect NS1 IgG ELISA, and compared the results with an E-based virus-like particle (VLP) GAC–ELISA. Results: NS1-based methods had comparable accuracies as VLP GAC–ELISA. Although the sensitivity in detecting anti-NS1 IgM was poor, indirect NS1 IgG ELISA showed similar limits of detection (~1–2 ng/mL) as NS1 GAC–ELISA in detecting anti-NS1 IgG. Combining the results from two or more tests as a composite reference standard can determine the DENV serostatus with a specificity reaching 100%. Conclusion: NS1-based ELISAs have comparable accuracies as VLP GAC–ELISA in determining dengue serostatus, which could effectively assist clinicians during assessments of vaccine eligibility.

Objective. This study aimed to determine the antiviral activity of ten Philippine medicinal plants against Zika virus (ZIKV). Methods. Lyophilized aqueous plant extracts were used for cell cytotoxicity and virus inhibition assays. The therapeutic index was computed from the 50% cytotoxic concentration (CC50) and 50% effective concentration (EC50) values. Plant metabolites were also identified using mass spectroscopy. An in-silico screening of these metabolites was done using ZIKV enzymes and the Axl protein in human microglial cells as target proteins, followed by the ranking of binding energy scores to generate a hypothesis on the possible mechanism of antiviral action.Results. The plants that demonstrated the highest therapeutic index were Momordica charantia, Psidium guajava, Vitex negundo, and Blumea balsamifera. The majority of the metabolites present in the aqueous extracts were saponin, terpenes and terpenoids, and anthocyanin. Further, in-silico docking results showed a higher binding affinity for viral replication proteins compared to the viral envelope protein.Conclusion. The crude aqueous extracts of M. charantia, P. guajava, V. negundo, and B. balsamifera were the most potent candidate antiviral therapies against ZIKV among the ten plants tested. Meanwhile, the in-silico results suggested that the metabolites possibly employ an intracellular mechanism for the observed antiviral activity.