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Acta Tropica Jun 2024Dengue fever is a viral illness, mainly transmitted by Aedes aegypti and Aedes albopictus. With climate change and urbanisation, more urbanised areas are becoming...
Dengue fever is a viral illness, mainly transmitted by Aedes aegypti and Aedes albopictus. With climate change and urbanisation, more urbanised areas are becoming suitable for the survival and reproduction of dengue vector, consequently are becoming suitable for dengue transmission in China. Chongqing, a metropolis in southwestern China, has recently been hit by imported and local dengue fever, experiencing its first local outbreak in 2019. However, the genetic evolution dynamics of dengue viruses and the spatiotemporal patterns of imported and local dengue cases have not yet been elucidated. Hence, this study implemented phylogenetic analyses using genomic data of dengue viruses in 2019 and 2023 and a spatiotemporal analysis of dengue cases collected from 2013 to 2022. We sequenced a total of 15 nucleotide sequences of E genes. The dengue viruses formed separate clusters and were genetically related to those from Guangdong Province, China, and countries in Southeast Asia, including Laos, Thailand, Myanmar and Cambodia. Chongqing experienced a dengue outbreak in 2019 when 168 imported and 1,243 local cases were reported, mainly in September and October. Few cases were reported in 2013-2018, and only six were imported from 2020 to 2022 due to the COVID-19 lockdowns. Our findings suggest that dengue prevention in Chongqing should focus on domestic and overseas population mobility, especially in the Yubei and Wanzhou districts, where airports and railway stations are located, and the period between August and October when dengue outbreaks occur in endemic regions. Moreover, continuous vector monitoring should be implemented, especially during August-October, which would be useful for controlling the Aedes mosquitoes. This study is significant for defining Chongqing's appropriate dengue prevention and control strategies.
PubMed: 38945422
DOI: 10.1016/j.actatropica.2024.107308 -
ACS Infectious Diseases Jun 2024The envelope protein of dengue virus (DENV) is a primary target of the humoral immune response. The domain III of the DENV envelope protein (EDIII) is known to be the...
The envelope protein of dengue virus (DENV) is a primary target of the humoral immune response. The domain III of the DENV envelope protein (EDIII) is known to be the target of multiple potently neutralizing antibodies. One such antibody is 3H5, a mouse antibody that binds strongly to EDIII and potently neutralizes DENV serotype 2 (DENV-2) with unusually minimal antibody-dependent enhancement (ADE). To selectively display the binding epitope of 3H5, we strategically modified DENV-2 EDIII by shielding other known epitopes with engineered N-glycosylation sites. The modifications resulted in a glycosylated EDIII antigen termed "EDIII mutant N". This antigen was successfully used to sift through a dengue-immune scFv-phage library to select for scFv antibodies that bind to or closely surround the 3H5 epitope. The selected scFv antibodies were expressed as full-length human antibodies and showed potent neutralization activity to DENV-2 with low or negligible ADE resembling 3H5. These findings not only demonstrate the capability of the N-glycosylated EDIII mutant N as a tool to drive an epitope-directed antibody selection campaign but also highlight its potential as a dengue immunogen. This glycosylated antigen shows promise in focusing the antibody response toward a potently neutralizing epitope while reducing the risk of antibody-dependent enhancement.
PubMed: 38943594
DOI: 10.1021/acsinfecdis.4c00058 -
Journal of Evolutionary Biology Jun 2024Comprehensive and systematic examination of Dengue virus (DENV) evolution is essential in the context of Pakistan as the virus presents a significant public health...
Comprehensive and systematic examination of Dengue virus (DENV) evolution is essential in the context of Pakistan as the virus presents a significant public health challenge with the ability to adapt and evolve. To shed light on intricate evolutionary patterns of all four DENV serotypes, we analyzed complete genome sequences (n=43) and envelope (E) gene sequences (n=44) of all four DENV serotypes collected in Pakistan from 1994 to 2023 providing a holistic view of their genetic evolution. Our findings revealed that all four serotypes of DENV co-circulate in Pakistan with a close evolutionary relationship between DENV-1 and DENV-3. Genetically distinct serotypes DENV-2 and DENV-4 indicate that DENV-4 stands out as the most genetically different, while DENV-2 exhibits greater complexity due to the presence of multiple genotypes and the possibility of temporal fluctuations in genotype prevalence. Selective pressure analysis in Envelope (E) gene revealed heterogeneity among sequences (n=44) highlighting 46 codons in the genome experiencing selective pressure, characterized by a bias towards balancing selection indicating genetic stability of the virus. Furthermore, our study suggested an intriguing evolutionary shift of DENV-4 towards the DENV-2 clade, potentially influenced by antibodies with cross-reactivity to multiple serotypes providing a critical insight into the complex factors shaping DENV evolution and contributing to the emergence of new serotype.
PubMed: 38943464
DOI: 10.1093/jeb/voae076 -
The Journal of Infectious Diseases Jun 2024There is an increasing global burden from chikungunya virus (CHIKV). Bangladesh reported a major epidemic in 2017, however, it was unclear if there had been prior...
There is an increasing global burden from chikungunya virus (CHIKV). Bangladesh reported a major epidemic in 2017, however, it was unclear if there had been prior widespread transmission. We conducted a nationally representative seroprevalence survey in 70 randomly selected communities immediately prior to the epidemic. We found 69/2,938 (2.4%) of sampled individuals were seropositive to CHIKV. Being seropositive to dengue virus (aOR 3.13 [95% CIs: 1.86-5.27]), male sex (aOR 0.59 [95% CIs: 0.36-0.99]), and community presence of Aedes aegypti mosquitoes (aOR: 1.80, 95% CI: 1.05-3.07) were significantly associated with CHIKV seropositivity. Using a spatial prediction model, we estimated that across the country, 4.99 (95% CI: 4.89 - 5.08) million people had been previously infected. These findings highlight high population susceptibility prior to the major outbreak and that previous outbreaks must have been spatially isolated.
PubMed: 38942731
DOI: 10.1093/infdis/jiae335 -
Journal of Virological Methods Jun 2024The most widely used invitro diagnostic qualitative screening method for dengue virus infection is the lateral flow immunoassay technique. Testing of dengue...
The most widely used invitro diagnostic qualitative screening method for dengue virus infection is the lateral flow immunoassay technique. Testing of dengue non-structural antigen NS1 offers specificity in determining the active infection while testing of IgM and IgG helps in differentiating the primary and secondary dengue infections. The ELISA functions as the golden standard for dengue testing and PCR credits for the most accurate determination tool at the genetic level. The RT-PCR endorsed NS1 gene and in ELISA or LFIA NS1 antigen is used as the marker owing to the specificity and lesser chances of mutation effects. This study evaluated the performance of AG-Q Dengue NS1 LFIA kit in comparison with RT-PCR quantification cycle (Cq) Values and ELISA NS1 quantitation. The study also focused on differentiating the samples among dengue serotypes using the RealStar Dengue Type RT-PCR Kit 1.0. Dengue serotype 2 is the prominent viral strain in Kerala region succeeded by serotype 3 and 1 with a prevalence rate of 64%, 20% and 6% respectively. Dengue serotype 4 was not reported during this study period. 10% co-infection with DENV 1 & DENV 2 was also reported. The AG-Q Dengue NS1 kit stood as efficient in screening by providing positive results with samples having RT-PCR Cq values up to 43 and ELISA NS1 quantification minimum of 14 Panbio units.
PubMed: 38942174
DOI: 10.1016/j.jviromet.2024.114991 -
Euro Surveillance : Bulletin Europeen... Jun 2024Oropouche fever is caused by Oropouche virus (OROV), transmitted primarily through the bite of infected midges, particularly of the genus . The virus is mainly...
Oropouche fever is caused by Oropouche virus (OROV), transmitted primarily through the bite of infected midges, particularly of the genus . The virus is mainly circulating in Central and South America where several countries reported an ongoing outbreak. We report here two imported cases of OROV infection identified in Italy, late May-early June 2024. These cases indicate that in the shadow of a massive dengue outbreak in the Americas, the Oropouche outbreak might be more widespread than previously estimated.
Topics: Humans; Italy; Travel; Male; Cuba; Adult; Orthobunyavirus; Animals; Disease Outbreaks; Bunyaviridae Infections; Middle Aged; Female
PubMed: 38940002
DOI: 10.2807/1560-7917.ES.2024.29.26.2400362 -
Journal of Medical Virology Jun 2024COVID-19 tended to be less aggressive in dengue endemic regions. Conversely, dengue cases plummeted in dengue endemic zones during the active years of the pandemic...
COVID-19 tended to be less aggressive in dengue endemic regions. Conversely, dengue cases plummeted in dengue endemic zones during the active years of the pandemic (2020-2021). We and others have demonstrated serological cross-reactivity between these two viruses of different families. We further demonstrated that COVID-19 serum samples that were cross-reactive in dengue virus (DV) serological tests, "cross-neutralized" all DV serotypes in Huh7 cells. Here we showed by co-immunoprecipitation (Co-IP) and atomic force microscopy (AFM) imaging that severe acute respiratory syndrome (SARS)-coronavirus (CoV)-2 (SARS-CoV-2) spike (S) protein subunit S1 and S2 monoclonal antibodies can indeed, bind to DV particles. Likewise, DV envelope antibodies (DV E Abs) showed high docking frequency with other human pathogenic beta-CoVs and murine hepatitis virus-1 (MHV-1). SARS-CoV-2 Ab didn't show docking or Co-IP with MHV-1 supporting poor cross-protection among CoVs. DV E Abs showed binding to MHV-1 (AFM, Co-IP, and immunofluorescence) and prepandemic dengue patients' serum samples even "cross-neutralized" MHV-1 plaques in cell culture. Furthermore, dengue serum samples showed marked inhibition potential in a surrogate virus-based competitive enzyme-linked immunosorbent assay, used for determining neutralizing Abs against SARS-CoV-2 S protein receptor-binding domain in COVID-19 serum samples. We therefore, provide multiple evidence as to why CoVs are epidemiologically less prevalent in highly dengue endemic regions globally.
Topics: Dengue Virus; Humans; Dengue; Cross Reactions; Antibodies, Viral; SARS-CoV-2; Spike Glycoprotein, Coronavirus; COVID-19; Antibodies, Neutralizing; Animals; Antibodies, Monoclonal; Endemic Diseases
PubMed: 38932494
DOI: 10.1002/jmv.29771 -
Vaccines Jun 2024T help (Th), stimulation of toll-like receptors (pathogen-associated molecular patterns, PAMPs), and antigen organization and repetitiveness (pathogen-associated...
Identifying Key Drivers of Efficient B Cell Responses: On the Role of T Help, Antigen-Organization, and Toll-like Receptor Stimulation for Generating a Neutralizing Anti-Dengue Virus Response.
T help (Th), stimulation of toll-like receptors (pathogen-associated molecular patterns, PAMPs), and antigen organization and repetitiveness (pathogen-associated structural patterns, PASPs) were shown numerous times to be important in driving B-cell and antibody responses. In this study, we dissected the individual contributions of these parameters using newly developed "Immune-tag" technology. As model antigens, we used eGFP and the third domain of the dengue virus 1 envelope protein (DV1 EDIII), the major target of virus-neutralizing antibodies. The respective proteins were expressed alone or genetically fused to the N-terminal fragment of the cucumber mosaic virus (CMV) capsid protein-nCMV, rendering the antigens oligomeric. In a step-by-step manner, RNA was attached as a PAMP, and/or a universal Th-cell epitope was genetically added for additional Th. Finally, a PASP was added to the constructs by displaying the antigens highly organized and repetitively on the surface of CMV-derived virus-like particles (CuMV VLPs). Sera from immunized mice demonstrated that each component contributed stepwise to the immunogenicity of both proteins. All components combined in the CuMV VLP platform induced by far the highest antibody responses. In addition, the DV1 EDIII induced high levels of DENV-1-neutralizing antibodies only if displayed on VLPs. Thus, combining multiple cues typically associated with viruses results in optimal antibody responses.
PubMed: 38932390
DOI: 10.3390/vaccines12060661 -
Vaccines May 2024The dengue virus, the primary cause of dengue fever, dengue hemorrhagic fever, and dengue shock syndrome, is the most widespread mosquito-borne virus worldwide. In...
The dengue virus, the primary cause of dengue fever, dengue hemorrhagic fever, and dengue shock syndrome, is the most widespread mosquito-borne virus worldwide. In recent decades, the prevalence of dengue fever has increased markedly, presenting substantial public health challenges. Consequently, the development of an efficacious vaccine against dengue remains a critical goal for mitigating its spread. Our research utilized Celcradle™, an innovative tidal bioreactor optimized for high-density cell cultures, to grow Vero cells for dengue virus production. By maintaining optimal pH levels (7.0 to 7.4) and glucose concentrations (1.5 g/L to 3.5 g/L) during the proliferation of cells and viruses, we achieved a peak Vero cell count of approximately 2.46 × 10, nearly ten times the initial count. The use of Celcradle™ substantially decreased the time required for cell yield and virus production compared to conventional Petri dish methods. Moreover, our evaluation of the immunogenicity of the Celcradle™-produced inactivated DENV4 through immunization of mice revealed that sera from these mice demonstrated cross-reactivity with DENV4 cultured in Petri dishes and showed elevated antibody titers compared to those from mice immunized with virus from Petri dishes. These results indicate that the dengue virus cultivated using the Celcradle™ system exhibited enhanced immunogenicity relative to that produced in traditional methods. In conclusion, our study highlights the potential of the Celcradle™ bioreactor for large-scale production of inactivated dengue virus vaccines, offering significant promise for reducing the global impact of dengue virus infections and accelerating the development of effective vaccination strategies.
PubMed: 38932292
DOI: 10.3390/vaccines12060563 -
Viruses May 2024The complete lack of yellow fever virus (YFV) in Asia, and the lack of urban YFV transmission in South America, despite the abundance of the peridomestic mosquito vector...
The complete lack of yellow fever virus (YFV) in Asia, and the lack of urban YFV transmission in South America, despite the abundance of the peridomestic mosquito vector () is an enigma. An immunologically naïve population of over 2 billion resides in Asia, with most regions infested with the urban YF vector. One hypothesis for the lack of Asian YF, and absence of urban YF in the Americas for over 80 years, is that prior immunity to related flaviviruses like dengue (DENV) or Zika virus (ZIKV) modulates YFV infection and transmission dynamics. Here we utilized an interferon α/β receptor knock-out mouse model to determine the role of pre-existing dengue-2 (DENV-2) and Zika virus (ZIKV) immunity in YF virus infection, and to determine mechanisms of cross-protection. We utilized African and Brazilian YF strains and found that DENV-2 and ZIKV immunity significantly suppresses YFV viremia in mice, but may or may not protect relative to disease outcomes. Cross-protection appears to be mediated mainly by humoral immune responses. These studies underscore the importance of re-assessing the risks associated with YF outbreak while accounting for prior immunity from flaviviruses that are endemic.
Topics: Animals; Yellow Fever; Mice; Cross Protection; Disease Models, Animal; Yellow fever virus; Zika Virus; Mice, Knockout; Zika Virus Infection; Dengue Virus; Receptor, Interferon alpha-beta; Antibodies, Viral; Flavivirus; Aedes; Dengue; Female; Viremia; Mosquito Vectors; Flavivirus Infections; Mice, Inbred C57BL
PubMed: 38932129
DOI: 10.3390/v16060836