#Covert #COVID19 and false-positive #dengue #serology in #Singapore (Lancet Infect Dis., summary)

[Source: The Lancet Infectious Diseases, full page: (LINK). Summary, edited.]

Covert COVID-19 and false-positive dengue serology in Singapore

Gabriel Yan, Chun Kiat Lee, Lawrence T M Lam, Benedict Yan, Ying Xian Chua, Anita Y N Lim, Kee Fong Phang, Guan Sen Kew, Hazel Teng, Chin Hong Ngai, Li Lin, Rui Min Foo, Surinder Pada, Lee Ching Ng, Paul Anantharajah Tambyah

Published: March 04, 2020 / DOI: https://doi.org/10.1016/S1473-3099(20)30158-4


Dengue and coronavirus disease 2019 (COVID-19) are difficult to distinguish because they have shared clinical and laboratory features.1, 2 We describe two patients in Singapore with false-positive results from rapid serological testing for dengue, who were later confirmed to have severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, the causative virus of COVID-19.



We declare no competing interests.

Keywords: SARS-CoV-2; COVID-19; Dengue fever; Diagnostic tests; Singapore.


#Reciprocal immune #enhancement of #dengue and #Zika virus #infection in #human #skin (JCI Insight, abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

JCI Insight. 2020 Jan 7. pii: 133653. doi: 10.1172/jci.insight.133653. [Epub ahead of print]

Reciprocal immune enhancement of dengue and Zika virus infection in human skin.

Castanha PM, Erdos G, Watkins SC, Falo LD Jr, Marques ET, Barratt-Boyes SM.



Dengue (DENV) and Zika viruses (ZIKV) are closely related mosquito-borne flaviviruses that co-circulate in tropical regions and constitute major threats to global human health. Whether preexisting immunity to one virus affects disease caused by the other during primary or secondary infections is unknown but is critical in preparing for future outbreaks and predicting vaccine safety. Using a human skin explant model, we show that DENV-3 immune sera increased recruitment and infection of Langerhans cells, macrophages and dermal dendritic cells following inoculation with DENV-2 or ZIKV. Similarly, ZIKV immune sera enhanced infection with DENV-2. Immune sera increased migration of infected Langerhans cells to dermis and emigration of infected cells out of skin. Heterotypic immune sera increased viral RNA in dermis almost tenfold and reduced the amount of virus required to infect a majority of myeloid cells by 100 to 1,000 fold. Enhancement was associated with cross-reactive IgG and induction of IL-10 expression and was mediated by both CD32 and CD64 Fcγ receptors. These findings reveal that preexisting heterotypic immunity greatly enhances DENV and ZIKV infection, replication and spread in human skin. This relevant tissue model will be valuable in assessing the efficacy and risk of dengue and Zika vaccines in humans.

KEYWORDS: Dendritic cells; Immunoglobulins; Immunology; Infectious disease; Macrophages

PMID: 31910161 DOI: 10.1172/jci.insight.133653

Keywords: Dengue fever; Zika Virus; ADE.


#Risk of #dengue in Central #Africa: #Vector competence studies with #Aedes aegypti and Aedes albopictus (Diptera: Culicidae) populations and dengue 2 virus (PLOS Negl Trop Dis., abstract)

[Source: PLOS Neglected Tropical Diseases, full page: (LINK). Abstract, edited.]


Risk of dengue in Central Africa: Vector competence studies with Aedes aegypti and Aedes albopictus (Diptera: Culicidae) populations and dengue 2 virus

Basile Kamgang , Marie Vazeille, Armel N. Tedjou, Theodel A. Wilson-Bahun, Aurélie P. Yougang, Laurence Mousson, Charles S. Wondji , Anna-Bella Failloux


Published: December 30, 2019 / DOI: https://doi.org/10.1371/journal.pntd.0007985 / This is an uncorrected proof.




Dengue is the most important mosquito-borne diseases worldwide but was considered scarce in West-Central Africa. During the last decade, dengue outbreaks have increasingly been reported in urban foci in this region suggesting major epidemiological changes. However, in Central Africa where both vectors, Aedes aegypti and Aedes albopictus are well established, the role of each species in dengue transmission remains poorly investigated.

Methodology/Principal findings

Field-collected strains of Ae. aegypti and Ae. albopictus from different ecological settings in Central Africa were experimentally challenged with dengue 2 virus (DENV-2). Mosquitoes were analysed at 14- and 21-days post-infection. Analysis provide evidence that both Ae. aegypti and Ae. albopictus in Central Africa were able to transmit dengue virus with Ae. aegypti exhibiting a higher transmission rate. Unexpectedly, two Ae. aegypti populations from Bénoué and Maroua, in northern Cameroon, were not able to transmit DENV-2.


We conclude that both Ae. aegypti and Ae. albopictus are susceptible to DENV-2 and may intervene as active dengue vectors. These findings highlight the urgent need to plan a vector surveillance program and control methods against dengue vectors in Central Africa in order to prevent future outbreaks.


Author summary

Dengue virus (DENV) is a flavivirus mainly transmitted to humans through the bite of infected mosquitoes notably Aedes aegypti and Aedes albopictus. In Central Africa where both vectors, Ae. aegypti and Ae. albopictus are well established, the role of each species in dengue transmission remains poorly investigated. Here, we assessed the vector competence of Ae. aegypti and Ae. albopictus collected in different ecological settings in Central Africa to transmit dengue 2 virus (DENV-2). We provide evidence that both Ae. aegypti and Ae. albopictus in Central Africa were able to transmit dengue virus with Ae. aegypti exhibiting a higher transmission rate. These findings could increase the risk of dengue outbreak in the region and emphasize the need for a comprehensive vector surveillance program to prevent and preparedness for an intervention in case of outbreaks.


Citation: Kamgang B, Vazeille M, Tedjou AN, Wilson-Bahun TA, Yougang AP, Mousson L, et al. (2019) Risk of dengue in Central Africa: Vector competence studies with Aedes aegypti and Aedes albopictus (Diptera: Culicidae) populations and dengue 2 virus. PLoS Negl Trop Dis 13(12): e0007985. https://doi.org/10.1371/journal.pntd.0007985

Editor: Duane J. Gubler, Duke-NUS GMS, SINGAPORE

Received: September 9, 2019; Accepted: December 10, 2019; Published: December 30, 2019

Copyright: © 2019 Kamgang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All relevant data are within the manuscript.

Funding: BK was funded by the Wellcome Trust, 204862/Z/16/Z (https://wellcome.ac.uk). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

Keywords: Flavivirus; Dengue fever; Africa region; Mosquitoes; Aedes aegypti; Aedes albopictus.


Full-Length #Genome #Sequence of a #Dengue serotype 1 virus isolate from a #traveller returning from #DRC to #Italy, July 2019 (Int J Infect Dis., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Int J Infect Dis. 2019 Dec 19. pii: S1201-9712(19)30496-5. doi: 10.1016/j.ijid.2019.12.023. [Epub ahead of print]

Full-Length Genome Sequence of a Dengue serotype 1 virus isolate from a traveller returning from Democratic Republic of Congo to Italy, July 2019.

Colavita F1, Vairo F2, Carletti F1, Boccardo C3, Ferraro F1, Iaiani G4, Al Moghazi S1, Galardo G3, Lalle E1, Selvaggi C1, Scognamiglio P1, Capobianchi MR1, Ippolito G1, Castilletti C1.

Author information: 1 National Institute for Infectious Diseases ‘Lazzaro Spallanzani’ IRCCS, 00149 Rome, Italy. 2 National Institute for Infectious Diseases ‘Lazzaro Spallanzani’ IRCCS, 00149 Rome, Italy. Electronic address: francesco.vairo@inmi.it. 3 Dipartimento di Emergenza e Accettazione, Policlinico Umberto 1, Rome, Italy. 4 Dipartimento di Malattie Infettive e Tropicali, Policlinico Umberto 1, Rome, Italy.



We report the full-genome sequence of a Dengue serotype-1 virus (DENV-1) isolated from a traveller returning in July 2019 to Italy from Democratic Republic of Congo (DRC), which is currently affected by Ebola and measles outbreaks. The sequence shows high similarity with two 2013 strains isolated in Angola and China.

Copyright © 2019. Published by Elsevier Ltd.

KEYWORDS: Democratic Republic of Congo; Dengue virus; Full-genome sequence; Travel-associated infection

PMID: 31866548 DOI: 10.1016/j.ijid.2019.12.023

Keywords: Dengue fever; DRC; Italy.


Association of #Allergic #Symptoms with #Dengue #Infection and #Severity: A Systematic Review and Meta-analysis (Virol Sin., abstract)

[Source: Virologica Sinica, full page: (LINK). Abstract, edited.]

Association of Allergic Symptoms with Dengue Infection and Severity: A Systematic Review and Meta-analysis

Authors: Nguyen Dang Kien, Amr Ehab El-Qushayri, Ali Mahmoud Ahmed, Adnan Safi, Sarch Abdel Mageed, Samar Muhammed Mehyar, Mohammad Rashidul Hashan, Sedighe Karimzadeh, Kenji Hirayama, Nguyen Tien Huy

RESEARCH ARTICLE / First Online: 21 October 2019



The relationship between the severity of dengue infection and allergy is still obscure. We conducted an electronic search across 12 databases for relevant articles reporting allergic symptoms, dengue infection, and dengue classification. These studies were categorized according to dengue severity and allergy symptoms, and a meta-analysis was performed by pooling the studies in each category. Among the included 57 articles, pruritus was the most common allergic sign followed by non-specified allergy and asthma (28.6%, 13%, and 6.5%, respectively). Despite the reported significant association of dengue with pruritus and total IgE level (P < 0.05), in comparison with non-dengue cases and healthy controls, there was no association between the different severe dengue group with pruritus, skin allergy, food allergy or asthma. However, removing the largest study revealed a significant association between asthma with dengue hemorrhagic fever (DHF) rather than dengue fever (DF). In comparison with DF, DHF was associated with IgE positivity. Furthermore, specific-IgE level was higher in secondary DF rather than primary DF. There was a possible association between allergy symptoms and dengue severity progression. Further studies are needed to clarify this association.

Keywords: Dengue – Allergy – Severity – IgE – Asthma – Association

Nguyen Dang Kien, Amr Ehab El-Qushayri and Ali Mahmoud Ahmed have contributed equally to this work.


Electronic supplementary material

The online version of this article ( https://doi.org/10.1007/s12250-019-00165-6) contains supplementary material, which is available to authorized users.




We acknowledged the contributions of Nguyen Thi Huyen Trang (Hue University of Medicine and Pharmacy, Hue City, Vietnam), Nguyen Phuoc Long, Le Phi Hung, and Nguyen Thien Luan (University of Medicine and Pharmacy at Ho Chi Minh City, Vietnam), Tran Thi Minh Hue (Hanoi Medical University, Vietnam) Doan Ngoc Dinh (Health Strategy and Policy Institute (HSPI),MoH Vietnam), Tran Dinh Trung (Da Nang University of Medical Technology and Pharmacy, Da Nang City, Vietnam) on the initial work of the study.

Author Contributions

NDK, AEE, AMA and NTH designed the experiments. NDK, AEE, AMA, AS, SAM, SMM, SK, MRH and KH collected the documents and summed up the data. NDK, AEE, AMA and NTH analyzed the data. NDK, AEE, AMA and NTH wrote the manuscript. All author read and approved the final manuscript.


Compliance with Ethical Standards

Conflict of interest

The authors declare that they have no conflict of interest.

Animal and Human Rights Statement

This article does not contain any studies with human or animal subjects performed by any of the authors.

Keywords: Dengue fever; Allergy.


#NS5 from #Dengue virus serotype 2 can adopt a conformation analogous to its #ZIKV and #JEV homologues (J Virol., abstract)

[Source: Journal of Virology, full page: (LINK). Abstract, edited.]

NS5 from Dengue virus serotype 2 can adopt a conformation analogous to its ZIKV and JEV homologues.

Abbas El Sahili, Tingjin Sherryl Soh, Jonas Schiltz, Aïcha Gharbi-Ayachi, Cheah Chen Seh, Pei-Yong Shi, Siew Pheng Lim, Julien Lescar

DOI: 10.1128/JVI.01294-19



Flavivirus non-structural protein 5 (NS5) contains a N-terminal methyltransferase domain (MTase) and a C-terminal polymerase domain (RdRp) fused through a nine-amino acid linker. While the individual NS5 domains are structurally conserved, in the full-length protein, their relative orientations fall into two classes: NS5 from JEV and ZIKV adopt one conformation, while NS5 from DENV3 another. Here, we report a crystallographic structure of NS5 from DENV2 in a conformation similar to the extended one seen in JEV and ZIKV NS5 crystal structures, albeit looser. Substituting DENV2 NS5 linker with DENV1, -3, -4, JEV and ZIKV NS5 linkers had modest or minimal effects on in vitro DENV2 MTase and RdRp activities. Heterotypic DENV NS5 linkers attenuated DENV2 replicon growth in cells, whilst JEV and ZIKV NS5 linkers abolished replication. Thus, JEV and ZIKV linkers likely hindered essential DENV2 NS5 interactions with other viral or host proteins within the virus replicative complex. Overall, this work sheds light on the dynamics of the multifunctional flavivirus NS5 protein and its interdomain linker. Targeting the NS5 linker is a possible strategy for producing attenuated flavivirus strains for vaccine design.



Flaviviruses include important human pathogens such as dengue or Zika virus. NS5 is a non-structural protein essential for flavivirus RNA replication, with dual MTase and RdRp enzyme activity and thus constitutes a major drug target. Insights into NS5 structure, dynamics and evolution should inform the development of antiviral inhibitors and vaccine design. We found that NS5 from DENV2 can adopt a conformation resembling NS5 from JEV and ZIKV. Substitution of DENV2 NS5 linker with JEV and ZIKV NS5 linkers abolished DENV2 replication in cells, without significantly impacting in vitro DENV2 NS5 enzymatic activities. We propose that heterotypic Flavivirus NS5 linkers impeded DENV2 NS5 protein-protein interactions that are essential for virus replication.

Copyright © 2019 American Society for Microbiology. All Rights Reserved.

Keywords: Flavivirus; Dengue fever; Zika Virus; Japanese Encephalitis virus.


Space–time #dynamics of a triple #epidemic: #dengue, #chikungunya and #Zika #clusters in the city of #Rio de Janeiro (Proc Roy Soc B., abstract)

[Source: Proceedings of the Royal Society, Biological Sciences, full page: (LINK). Abstract, edited.]

Space–time dynamics of a triple epidemic: dengue, chikungunya and Zika clusters in the city of Rio de Janeiro

Laís Picinini Freitas, Oswaldo Gonçalves Cruz, Rachel Lowe and Marilia Sá Carvalho

Published: 09 October 2019 / DOI: https://doi.org/10.1098/rspb.2019.1867



Dengue, an arboviral disease transmitted by Aedes mosquitoes, has been endemic in Brazil for decades. However, vector-control strategies have not led to a significant reduction in the disease burden and have not been sufficient to prevent chikungunya and Zika entry and establishment in the country. In Rio de Janeiro city, the first Zika and chikungunya epidemics were detected between 2015 and 2016, coinciding with a dengue epidemic. Understanding the behaviour of these diseases in a triple epidemic scenario is a necessary step for devising better interventions for prevention and outbreak response. We applied scan statistics analysis to detect spatio-temporal clustering for each disease separately and for all three simultaneously. In general, clusters were not detected in the same locations and time periods, possibly owing to competition between viruses for host resources, depletion of susceptible population, different introduction times and change in behaviour of the human population (e.g. intensified vector-control activities in response to increasing cases of a particular arbovirus). Simultaneous clusters of the three diseases usually included neighbourhoods with high population density and low socioeconomic status, particularly in the North region of the city. The use of space–time cluster detection can guide intensive interventions to high-risk locations in a timely manner, to improve clinical diagnosis and management, and pinpoint vector-control measures.

Keywords: Zika Virus; Dengue Fever; Chikungunya fever; Brazil.