The prevalence of dengue infection poses a great public health concern among people living in tropical and subtropical countries like the Philippines. Just recently in 2019, the Philippines had a dengue virus (DENV) outbreak where nearly half of the mortalities were children between 5 and 9 years of age, and around 73% of confirmed DENV cases were under the age of 19. Children are disproportionately affected and are considered to be highly vulnerable to severe dengue infection compared to adults due to several factors. These include: immunological differences--poorly developed immune systems, making them more susceptible to the virus; smaller body sizes and weight means that they are more likely to experience severe symptoms; and their tendency to play outdoors, make them more exposed to mosquito bites. Hence, this article provides an overview of the current understanding for the vulnerability of children to severe dengue infection compared to adults
dengue virus ; dengue shock syndrome

Objective: To assess the incidence of dengue fever and E gene evolution of dengue virus in Guangzhou in 2020 and understand the local epidemiological characteristics of dengue fever and spreading of dengue virus. Methods: The information of dengue fever cases in Guangzhou in 2020 was collected from Notifiable Infectious Disease System of Chinese Center for Disease Control and Prevention Information System. Serum samples from the cases were detected by real-time PCR. The E gene was sequenced and analyzed. Maximum likelihood phylogenetic trees were constructed using software MEGA 5.05. The statistical analysis was conducted using software SPSS 20.0. Results: A total of 33 dengue fever cases were reported in Guangzhou in 2020, including 31 (93.94%) imported cases and 2 (6.06%) local cases. Compared with the data during 2016 to 2019, the number of cases, overall incidence and local incidence all decreased with statistically significant differences (all P<0.05). The imported cases from Southeast Asia constituted 90.32% (28/31) of imported cases. The E gene sequences and the phylogenetic trees of imported and local cases demonstrated close relationship with the virus sequences from Southeast Asian, and they were less homologous with the sequences of dengue virus isolated in Guangzhou in previous years. Conclusions: The incidence of dengue in Guangzhou in 2020 was significantly affected by the imported cases, especially those from Southeast Asian countries. The study result demonstrated that dengue fever was not endemic in Guangzhou and it was caused by imported ones.
China/epidemiology* ; Dengue/epidemiology* ; Dengue Virus/genetics* ; Disease Outbreaks ; Evolution, Molecular ; Genotype ; Humans ; Phylogeny

Dengue virus (DENV) is the most widely transmitted arbovirus in the world. Due to the lack of diagnostic technology to quickly identify the virus serotypes in patients, severe dengue hemorrhagic fever cases caused by repeated infections remain high. To realize the rapid differential diagnosis of different serotypes of DENV infection by immunological methods, in this study, four DENV serotype NS1 proteins were expressed and purified in mammalian cells. Monoclonal antibodies (MAbs) against NS1 protein were obtained by hybridoma technology after immunizing BALB/c mice. Enzyme-linked immunosorbent assay, indirect immunofluorescence assay, dot blotting, and Western blotting were used to confirm the reactivity of MAbs to viral native NS1 and recombinant NS1 protein. These MAbs include not only the universal antibodies that recognize all DENV 1-4 serotype NS1, but also serotype-specific antibodies against DENV-1, DENV-2 and DENV-4. Double antibody sandwich ELISA was established based on these antibodies, which can be used to achieve rapid differential diagnosis of serotypes of DENV infection. Preparation of DENV serotype-specific MAbs and establishment of an ELISA technology for identifying DENV serotypes has laid the foundation for the rapid diagnosis of DENV clinical infection.
Animals ; Antibodies, Monoclonal ; Antibodies, Viral/metabolism* ; Dengue/diagnosis* ; Dengue Virus/immunology* ; Enzyme-Linked Immunosorbent Assay ; Humans ; Mice ; Mice, Inbred BALB C ; Sensitivity and Specificity ; Serogroup ; Viral Nonstructural Proteins/immunology*

A rapid diagnostic test (RDT) kit was developed to detect non-structural protein 1 (NS1) of yellow fever virus (YFV) using monoclonal antibody. NS1 protein was purified from the cultured YFV and used to immunize mice. Monoclonal antibody to NS1 was selected and conjugated with colloidal gold to produce the YFV NS1 RDT kit. The YFV RDTs were evaluated for sensitivity and specificity using positive and negative samples of monkeys from Brazil and negative human blood samples from Korea. Among monoclonal antibodies, clones 3A11 and 3B7 proved most sensitive, and used for YFV RDT kit. Diagnostic accuracy of YFV RDT was fairly high; Sensitivity was 0.0% and specificity was 100% against Dengue viruses type 2 and 3, Zika, Chikungunya and Mayaro viruses. This YFV RDT kit could be employed as a test of choice for point-of-care diagnosis and large scale surveys of YFV infection under clinical or field conditions in endemic areas and on the globe.
Animals ; Antibodies, Monoclonal ; Brazil ; Clone Cells ; Dengue Virus ; Diagnosis ; Diagnostic Tests, Routine ; Gold Colloid ; Haplorhini ; Humans ; Korea ; Mice ; Point-of-Care Systems ; Sensitivity and Specificity ; Yellow fever virus ; Yellow Fever

ELISAs and rapid diagnostic tests (RDTs) are widely used for diagnosing dengue virus (DENV) infection. Using 138 single blood samples, we compared the ability to detect non-structural (NS)-1 antigen and anti-DENV IgM/IgG antibodies among (1) DENV Detect NS1 ELISA, DENV Detect IgM capture ELISA and DENV Detect IgG ELISA (InBios International, Inc.); (2) Anti-Dengue virus IgM Human ELISA and Anti-Dengue virus IgG Human ELISA (Abcam); (3) Dengue virus NS1 ELISA, Anti-Dengue virus ELISA (IgM) and Anti-Dengue virus ELISA (IgG) (Euroimmun); (4) Asan Easy Test Dengue NS1 Ag 100 and Asan Easy Test Dengue IgG/IgM (Asan Pharm); (5) SD BIOLINE Dengue Duo (Standard Diagnostics); and (6) Ichroma Dengue NS1 and Ichroma Dengue IgG/IgM (Boditech Med). For NS1 antigen detection, InBios and Euroimmun showed higher sensitivities (100%) than the RDTs (42.9–64.3%). All tests demonstrated variable sensitivities for IgM (38.1–90.5%) and IgG (65.7–100.0%). InBios and Boditech Med demonstrated higher sensitivity (95.6% and 88.2%, respectively) than the other tests for combined NS1 antigen and IgM antibody. Five NS1 antigen tests had good agreement (92.8–98.6%) without showing positivity for chikungunya. However, all IgG tests demonstrated potential false-positivity with variable ranges. Clinical laboratories should note performance variations across tests and potential cross-reactivity.
Antibodies ; Chungcheongnam-do ; Dengue Virus ; Dengue ; Diagnosis ; Diagnostic Tests, Routine ; Enzyme-Linked Immunosorbent Assay ; Humans ; Immunoglobulin G ; Immunoglobulin M

OBJECTIVES: Dengue epidemic is a dynamic and complex phenomenon that has gained considerable attention due to its injurious effects. The focus of this study is to statically analyze the nature of the dengue epidemic network in terms of whether it follows the features of a scale-free network or a random network. METHODS: A multifarious network of Aedes aegypti is addressed keeping the viewpoint of a complex system and modelled as a network. The dengue network has been transformed into a one-mode network from a two-mode network by utilizing projection methods. Furthermore, three network features have been analyzed, the power-law, clustering coefficient, and network visualization. In addition, five methods have been applied to calculate the global clustering coefficient. RESULTS: It has been observed that dengue epidemic follows a power-law, with the value of its exponent γ = −2.1. The value of the clustering coefficient is high for dengue cases, as weight of links. The minimum method showed the highest value among the methods used to calculate the coefficient. Network visualization showed the main areas. Moreover, the dengue situation did not remain the same throughout the observed period. CONCLUSIONS: The results showed that the network topology exhibits the features of a scale-free network instead of a random network. Focal hubs are highlighted and the critical period is found. Outcomes are important for the researchers, health officials, and policy makers who deal with arbovirus epidemic diseases. Zika virus and Chikungunya virus can also be modelled and analyzed in this manner.
Administrative Personnel ; Aedes ; Arboviruses ; Chikungunya virus ; Critical Period (Psychology) ; Dengue Virus ; Dengue ; Humans ; Methods ; Zika Virus

OBJECTIVES: To estimate the number and risk of imported infections resulting from people visiting Asian and Latin American countries.METHODS: The dataset of visitors to 5 Asian countries with dengue were analyzed for 2016 and 2017, and in the Philippines, Thailand and Vietnam, imported cases of zika virus infection were also reported. For zika virus, a single imported case was reported from Brazil in 2016, and 2 imported cases reported from the Maldives in 2017. To understand the transmissibility in 5 Southeast Asian countries, the estimate of the force of infection, i.e., the hazard of infection per year and the average duration of travel has been extracted. Outbound travel numbers were retrieved from the World Tourism Organization, including business travelers.RESULTS: The incidence of imported dengue in 2016 was estimated at 7.46, 15.00, 2.14, 4.73 and 2.40 per 100,000 travelers visiting Philippines, Indonesia, Thailand, Malaysia and Vietnam, respectively. Similarly, 2.55, 1.65, 1.53, 1.86 and 1.70 per 100,000 travelers in 2017, respectively. It was estimated that there were 60.1 infections (range: from 16.8 to 150.7 infections) with zika virus in Brazil, 2016, and 345.6 infections (range: from 85.4 to 425.5 infections) with zika virus in the Maldives, 2017.CONCLUSION: This study emphasizes that dengue and zika virus infections are mild in their nature, and a substantial number of infections may go undetected. An appropriate risk assessment of zika virus infection must use the estimated total size of infections.
Asia, Southeastern ; Asian Continental Ancestry Group ; Brazil ; Commerce ; Dataset ; Dengue ; Humans ; Incidence ; Indian Ocean Islands ; Indonesia ; Korea ; Latin America ; Malaysia ; Philippines ; Risk Assessment ; Thailand ; Vietnam ; Zika Virus ; Zika Virus Infection

OBJECTIVES: The aim of this study was to assess community participation in Dengue virus control measures, and community satisfaction in the Dengue surveillance workers (DSWs) performance in Semarang municipality after 3 years of empowerment.METHODS: A cross-sectional survey involved 1,018 selected participants from 12 groups of social roles in 141 villages in Semarang municipality, Indonesia. A direct interview was performed using a structured questionnaire to evaluate the acceptance, and satisfaction of the community towards the DSWs. The data were analyzed descriptively.RESULTS: The majority of the members of the community considered that the DSWs play an important role in reducing Dengue cases, and vectors of the Dengue virus, as well as increasing the community participation in Dengue control measures. The survey showed that DSWs performance, attitudes, and abilities regarding their main tasks were perceived to be good.CONCLUSION: Overall, people in Semarang municipality were satisfied with the performance of the DSWs, and considered them important enough to be maintained and strengthened in the future so that Dengue could be controlled. This new policy needs to be disseminated to other regions that may encounter the problems associated with Dengue virus.
Consumer Participation ; Cross-Sectional Studies ; Dengue Virus ; Dengue ; Indonesia ; Power (Psychology) ; Public Health

PURPOSE: The number of dengue fever cases is rising due to increasing overseas travel. Vaccination makes severe dengue fever in seronegative individuals after vaccination when they exposure to wild-type dengue virus. We investigated the seroepidemiology of the dengue virus for monitoring of Korean dengue virus immunity and establishing the prevention of dengue infection. METHODS: The study was based on 446 residual sera collected from 98 infants (2 months to 1 year old), 152 adolescents (13 to 19 years old), 90 adults (20 to 50 years old), and 106 elderly participants (more than 65 years old) for other studies. Antibody levels for dengue virus immunoglobulin G (IgG) in each age group were measured using an enzyme-linked immunosorbent assay (ELISA). For each dengue virus IgG positive or equivocal result, an IgG ELISA was performed for Japanese encephalitis virus. RESULTS: Of the 446 serum samples, only 1 (0.2%) adolescent had a positive result from the dengue IgG antibody test. In the dengue virus IgG antibody test, 14 (3.1%) samples showed equivocal results (10 adolescents and 4 elderly). In the 1 positive case of dengue virus IgG, the Japanese encephalitis IgG test was also positive. In the 14 equivocal cases of dengue virus IgG, there were 6 positive, 3 equivocal, and 5 negative of Japanese encephalitis IgG. CONCLUSIONS: The seroprevalence rate of dengue virus was very low in Koreans. This study provides important data for establishing the policy for preventive measures of dengue fever. It will be necessary to continuously monitor for dengue virus immunity.
Adolescent ; Adult ; Aged ; Dengue Virus ; Dengue ; Encephalitis Virus, Japanese ; Encephalitis, Japanese ; Enzyme-Linked Immunosorbent Assay ; Fever ; Humans ; Immunoglobulin G ; Infant ; Korea ; Prevalence ; Seroepidemiologic Studies ; Severe Dengue ; Vaccination

We developed a Rapid Diagnostic Test (RDT) kit for detecting IgG/IgM antibodies against Zika virus (ZIKV) using monoclonal antibodies to the envelope (E) and non-structural protein 1 (NS1) of ZIKV. These proteins were produced using baculovirus expression vector with Sf9 cells. Monoclonal antibodies J2G7 to NS1 and J5E1 to E protein were selected and conjugated with colloidal gold to produce the Zika IgG/IgM RDT kit (Zika RDT). Comparisons with ELISA, plaque reduction neutralization test (PRNT), and PCR were done to investigate the analytical sensitivity of Zika RDT, which resulted in 100% identical results. Sensitivity and specificity of Zika RDT in a field test was determined using positive and negative samples from Brazil and Korea. The diagnostic accuracy of Zika RDT was fairly high; sensitivity and specificity for IgG was 99.0 and 99.3%, respectively, while for IgM it was 96.7 and 98.7%, respectively. Cross reaction with dengue virus was evaluated using anti-Dengue Mixed Titer Performance Panel (PVD201), in which the Zika RDT showed cross-reactions with DENV in 16.7% and 5.6% in IgG and IgM, respectively. Cross reactions were not observed with West Nile, yellow fever, and hepatitis C virus infected sera. Zika RDT kit is very simple to use, rapid to assay, and very sensitive, and highly specific. Therefore, it would serve as a choice of method for point-of-care diagnosis and large scale surveys of ZIKV infection under clinical or field conditions worldwide in endemic areas.
Antibodies ; Antibodies, Monoclonal ; Baculoviridae ; Brazil ; Cross Reactions ; Dengue Virus ; Diagnosis ; Diagnostic Tests, Routine ; Enzyme-Linked Immunosorbent Assay ; Flavivirus ; Gold Colloid ; Hepacivirus ; Immunoglobulin G ; Immunoglobulin M ; Korea ; Methods ; Neutralization Tests ; Point-of-Care Systems ; Polymerase Chain Reaction ; Reagent Kits, Diagnostic ; Sensitivity and Specificity ; Sf9 Cells ; Yellow Fever ; Zika Virus