The four serotypes of dengue virus (DENV-1 to -4) cause the most important arthropod-borne viral disease of humans. DENV non-structural protein 5 (NS5) contains enzymatic activities required for capping and replication of the viral RNA genome that occurs in the host cytoplasm. However, previous studies have shown that DENV-2 NS5 accumulates in the nucleus during infection. In this study, we examined the nuclear localization of NS5 for all four DENV serotypes. We demonstrate for the first time that there are serotypic differences in NS5 nuclear localization. Whereas the DENV-2 and -3 proteins accumulate in the nucleus, DENV-1 and -4 NS5 are predominantly if not exclusively localized to the cytoplasm. Comparative studies on the DENV-2 and -4 NS5 proteins revealed that the difference in DENV-4 NS5 nuclear localization was not due to rapid nuclear export but rather the lack of a functional nuclear localization sequence. Interaction studies using DENV-2 and -4 NS5 and human importin-α isoforms failed to identify an interaction that supported the differential nuclear localization of NS5. siRNA knockdown of the human importin-α isoform KPNA2, corresponding to the murine importin-α isoform previously shown to bind to DENV-2 NS5, did not substantially affect DENV-2 NS5 nuclear localization, whereas knockdown of importin-β did. The serotypic differences in NS5 nuclear localization did not correlate with differences in IL-8 gene expression. The results show that NS5 nuclear localization is not strictly required for virus replication but is more likely to have an auxiliary function in the life cycle of specific DENV serotypes.

The development of live viral vaccines relies on empirically derived phenotypic criteria, especially small plaque sizes, to indicate attenuation. However, while some candidate vaccines successfully translated into licensed applications, others have failed safety trials, placing vaccine development on a hit-or-miss trajectory. We examined the determinants of small plaque phenotype in two dengue virus (DENV) vaccine candidates, DENV-3 PGMK30FRhL3, which produced acute febrile illness in vaccine recipients and DENV-2 PDK53, which has a good clinical safety profile. The reasons behind the failure of PGMK30FRhL3 during phase 1 clinical trial, despite meeting the empirically derived criteria of attenuation, have never been systematically investigated. Using in vitro, in vivo and functional genomics approaches, we examined infections by the vaccine and wild-type DENVs, in order to ascertain the different determinants of plaque size. We show that PGMK30FRhL3 produces small plaques on BHK-21 cells due to its slow in vitro growth rate. In contrast, PDK53 replicates rapidly, but is unable to evade antiviral responses that constrain its spread hence also giving rise to small plaques. Therefore, at least two different molecular mechanisms govern the plaque phenotype; determining which mechanism operates to constrain plaque size may be more informative on the safety of live-attenuated vaccines.

Background and aim: Hepatocellular carcinoma (HCC) is a significant complication of hepatitis B and still poses a global public health concern. This systematic review and meta-analysis provide adequate details on the prevalence of HCC in the HBV population within Southeast Asian countries. Method: Following the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) criteria, a thorough search for literature discussing the prevalence of HCC in the HBV population within southeast Asia was performed. Eligible studies were subjected to a meta-analysis utilising a DerSimonian and Laird approach and a random effect model. A protocol was registered with PROSPERO (CRD42023423953). Result: Our study meticulously recovered 41 articles from seven countries in Southeast Asia, namely Cambodia, Indonesia, Malaysia, the Philippines, Singapore, Thailand, and Vietnam. A total of 39,050 HBV patients and 7479 HCC cases in southeast Asia were analysed. The pooled prevalence of HCC in HBV cases within southeast Asia was 45.8% (95% CI, 34.3–57.8%, I² = 99.51%, p < 0.001). Singapore (62.5%, CI: 42.4–79.1) had the highest pooled prevalence of HCC in the HBV population compared to Vietnam, with the lowest estimate (22.4%, CI: 9.9–44.9). There was a drop in the pooled prevalence of HCC in HBV from 2016 until now (37.6%, CI: 19.2–60.5). Conclusion: The findings of this review reveal a high pooled prevalence of HCC in the HBV population and therefore stir the need for routine screening, management, and surveillance.

Objectives: To study the genotype and allele frequency of the fat mass and obesity-associated (FTO) rs8050136 A>C genetic variant and investigate its association with type 2 diabetes mekkitus (T2DM) parameters. Methods: This study was carried out on 118 diabetic patients and 106 healthy individuals (control) from Prince Mohammed bin Abdulaziz Hospital, Al Madinah Al Munawarah, Saudi Arabia. The TaqMan single-nucleotide polymorphism (SNP)genotyping assay was used for rs8050136 genotyping. Results: The frequency of the genotype AA was the same among T2DM and healthy control groups (21%). However, the frequency of genotype CC was 19.5% in T2DM patients and 24.5% in control individuals. There was no significant association between FTO SNP rs8050136 and an increased risk of T2DM. Furthermore, there was no association between the risk AA genotype and fasting blood glucose (p=0.092), glycated hemoglobin (p=0.177), or body mass index (p=0.561). Conclusion: Our findings show that the FTO rs8050136 A>C variant is not associated with T2DM in the Saudi population.

Lassa fever, commonly known as Lassa hemorrhagic fever (LHF), is one of the progressive illnesses invading a large population of two to three million individuals in West Africa. The infection transmitted through the rodents severely impacts the local population and the medical professionals in surrounding areas, which were also the primary target of LHF. In epidemic areas, Lassa fever causes a public health threat since it poses a significant morbidity and fatality Case rate (CFR) ≥ 50%). The disease is widespread in West Africa and has developed into one of the most common and life-threatening viral hemorrhagic fevers. Monitoring and preventing persistent disease outbreaks has been challenging in affected regions due to insufficient healthcare facilities, diagnostics labs, care centers, and low socioeconomic conditions. An absence of public awareness and the emergence of an ecological niche is advantageous for the survival and multiplication of the mouse (Mastomys natalensis) inhabiting the Lassa virus serving as the disease's natural host and reservoir. The current review focuses on early diagnosis and appropriate treatment, highlighting the immediate requirement of clinically approved vaccines for LHF, causing preventative and control actions more difficult in the present era.