There’s been a huge uptick in dengue research since climate change began to double the disease’s range and it started afflicting people in rich countries. Here’s a great database, from Harvard University, that will let you do your own research:
And here’s a fascinating development in the antigenic properties of the four dengue virus types:
“An international consortium of laboratories worldwide that are studying the differences among dengue viruses has shown that while the long-held view that there are four genetically-distinct types of the virus holds, far more important are the differences in their antigenic properties – the ‘coats’ that the viruses wear that help our immune systems identify them.
Dengue virus infects up to 390 million people each year. Around a quarter of these people will experience fever, headaches and joint pains, but approximately 500,000 people will experience potentially life-threatening complications, including haemorrhage and shock, where dangerously low blood pressure occurs. There are currently no vaccines against infection with dengue virus.
For decades, scientists have thought that there are four genetically-distinct types of the virus, known as serotypes, and that antigenic differences between the types play a key role in the severity of disease, its epidemiology and how the virus evolves – and hence these differences would be important in vaccine design.
When we become infected, our immune system sends out antibodies to try and identify the nature of the infection. If it is a pathogen – a virus or bacteria – that we have previously encountered, the antibodies will recognise the invader by antigens on its surface and set of a cascade of defences to prevent the infection taking hold. However, as pathogens evolve, they can change their antigens and disguise themselves against detection.
One of the unusual aspects of dengue is that in some cases when an individual becomes infected for a second time, rather than being immune to infection, the disease can be much more severe. One hypothesis to explain this is that the antibodies produced in response to infection with one strain of the virus somehow allow viruses of a different strain to enter undetected into cells, implying that antigenic differences between the serotypes are important.
Researchers from the Dengue Antigenic Cartography Consortium, writing in today’s edition of Science, analysed 47 strains of dengue virus with 148 samples taken from both humans and primates to see whether they indeed fit into four distinct types. The researchers found a significant amount of antigenic difference within each dengue serotype – in fact, the amount of difference within each serotype was of a similar order to that between the different types. This implies that an individual infected with one type may not be protected against antigenically different viruses of the same type, and that in some cases the individual may be protected against some antigenically similar strains of a different type.
Leah Katzelnick, a researcher from the Department of Zoology at the University of Cambridge, who began studying dengue after herself contracting the disease, says: “We were surprised at how much variation we saw…” Read more..
And here’s a useful discovery from a team at the University of Texas:
How dengue virus adapts as it travels
GALVESTON, Texas, July 6, 2015 – A researcher from The University of Texas Medical Branch at Galveston is an integral member of a collaborative group that is the first to explain the mechanisms that the Dengue virus has developed to optimize its ability to cause outbreaks as it travels across the globe to new places and revisits old ones. An early online version of this paper detailing the findings has recently been published in Science.
Dengue virus has been spreading throughout warm regions of the world, prompting the virus to adapt to new environments. This diversification in viral strains has resulted in the development of strains that appear associated with greater potential for sparking epidemics. Several dengue outbreaks have occurred when new dengue strains emerged and displaced the native strains that the local population had already developed immunity against. Until now, the mechanisms governing how and why some viral strains are better suited for causing widespread disease has been poorly understood.
The investigators examined the different clades of dengue virus-2 known to be circulating around Puerto Rico in 1994 when a severe epidemic broke out. Investigating the differences between the virus strain that was most commonly seen from 1986 to 1995 and a new, more potent viral strain that was first isolated in 1994 was the key to figuring out why this outbreak occurred.
They identified an interaction between the newcomer virus’s RNA and proteins within the host that allows the virus to bypass the host’s immune response, making it easier for the virus to invade. Based on the findings, the research team devised a model to explain the 1994 dengue outbreak in Puerto Rico.
“This study highlights the critical and oft forgotten role played by non-coding RNAs in the battle between viruses and their human hosts,” said author Mariano Garcia-Blanco, UTMB professor and chair of the department of biochemistry and molecular biology and also professor of emerging infectious diseases at the Duke-NUS Graduate Medical School in Singapore. “It emphasizes the importance of multidisciplinary research: a fabulous marriage of basic RNA biology and clinically informed epidemiology uncovered an unexpected route of virus evolution that explained (and perhaps could predict) epidemic potential.”
Other authors of this paper include Gayathri Manokaran, Esteban Finol, Jayantha Gunaratne, Eugenia Z. Ong, Hwee Cheng Tan, October M. Sessions, Alex M. Ward, Duane J. Gubler and corresponding author Eng Eong Ooi from the Duke-NUS Graduate Medical School; Chunling Wang, and Eva Harris from the University of California, Berkeley and Justin Bahl from the University of Texas School of Public Health, Houston.
This research was supported by the Singapore National Medical Research Council, the Ministry of Health in Singapore, Institute of Molecular and Cell Biology, Agency of Science, Technology and Research in Singapore and the U.S. National Institutes of Health.
Here are some links to dengue research in PLOS1:
Dengue Serosurvey in Sint EustatiusResearch Article | published 10 Jun 2014 | PLOS ONE10.1371/journal.pone.0095002Views: 741 • Citations: None • Saves: 5 • Shares: 7
- The Incubation Periods of Dengue VirusesResearch Article | published 30 Nov 2012 | PLOS ONE10.1371/journal.pone.0050972Views: 11,298 • Citations: 23 • Saves: 57 • Shares: 3
- Imported Dengue Cases, Weather Variation and Autochthonous Dengue Incidence in Cairns, AustraliaResearch Article | published 13 Dec 2013 | PLOS ONE10.1371/journal.pone.0081887Views: 1,186 • Citations: None • Saves: 7 • Shares: 1
- Dengue Virus Tropism in Humanized Mice Recapitulates Human Dengue FeverResearch Article | published 10 Jun 2011 | PLOS ONE10.1371/journal.pone.0020762Views: 4,674 • Citations: 22 • Saves: 43 • Shares: 1
- Distribution of Fitness in Populations of Dengue VirusesResearch Article | published 15 Sep 2014 | PLOS ONE10.1371/journal.pone.0107264Views: 632 • Citations: None • Saves: None • Shares: None
- Lung in Dengue: Computed Tomography FindingsResearch Article | published 16 May 2014 | PLOS ONE10.1371/journal.pone.0096313Views: 1,107 • Citations: None • Saves: 1 • Shares: 11
- Worldwide Spread of Dengue Virus Type 1Research Article | published 13 May 2013 | PLOS ONE10.1371/journal.pone.0062649Views: 4,974 • Citations: 5 • Saves: 32 • Shares: 9
- Sphingosine 1-Phosphate in Acute Dengue InfectionResearch Article | published 19 Nov 2014 | PLOS ONE10.1371/journal.pone.0113394Views: 62 • Citations: None • Saves: None • Shares: None
- Evaluation of the Performance of a Dengue Outbreak Detection Tool for ChinaResearch Article | published 29 Aug 2014 | PLOS ONE10.1371/journal.pone.0106144Views: 561 • Citations: None • Saves: None • Shares: None
- Dengue Virus Neutralization in Cells Expressing Fc Gamma ReceptorsResearch Article | published 22 May 2013 | PLOS ONE10.1371/journal.pone.0065231Views: 2,416 • Citations: 1 • Saves: 17 • Shares: None
- Emergence and Diversification of Dengue 2 Cosmopolitan Genotype in Pakistan, 2011Research Article | published 08 Mar 2013 | PLOS ONE10.1371/journal.pone.0056391Views: 2,402 • Citations: 4 • Saves: 13 • Shares: 3
- Release of Dengue Virus Genome Induced by a Peptide InhibitorResearch Article | published 30 Nov 2012 | PLOS ONE10.1371/journal.pone.0050995Views: 2,298 • Citations: 4 • Saves: 22 • Shares: 7
- Cellular and Cytokine Correlates of Severe Dengue InfectionResearch Article | published 29 Nov 2012 | PLOS ONE10.1371/journal.pone.0050387Views: 4,001 • Citations: 11 • Saves: 28 • Shares: None
- Differential Requirements in Endocytic Trafficking for Penetration of Dengue VirusResearch Article | published 07 Sep 2012 | PLOS ONE10.1371/journal.pone.0044835Views: 3,691 • Citations: 7 • Saves: 22 • Shares: 4
- Defective Interfering Viral Particles in Acute Dengue InfectionsResearch Article | published 29 Apr 2011 | PLOS ONE10.1371/journal.pone.0019447Views: 4,306 • Citations: 24 • Saves: 35 • Shares: None.