Dengue: A global burden.. and some news from India
Here is a link to a must read not so recent paper, in Nature, on the global prevalence of dengue. One of the authors is Jeremy Farrar who will soon take charge as Director of the Wellcome Trust. Farrar has done stellar research in tropical diseases in the Trust’s labs in Vietnam.
Here is the abstract of the article published in Nature. Note the last sentence. The DBT has programs and support in dengue research working on those lines. The Abstract: “Dengue is a systemic viral infection transmitted between humans by Aedes mosquitoes. For some patients, dengue is a life-threatening illness. There are currently no licensed vaccines or specific therapeutics, and substantial vector control efforts have not stopped its rapid emergence and global spread. The contemporary worldwide distribution of the risk of dengue virus infections and its public health burden are poorly known. Here we undertake an exhaustive assembly of known records of dengue occurrence worldwide, and use a formal modelling framework to map the global distribution of dengue risk. We then pair the resulting risk map with detailed longitudinal information from dengue cohort studies and population surfaces to infer the public health burden of dengue in 2010. We predict dengue to be ubiquitous throughout the tropics, with local spatial variations in risk influenced strongly by rainfall, temperature and the degree of urbanization. Using cartographic approaches, we estimate there to be 390 million (95% credible interval 284–528) dengue infections per year, of which 96 million (67–136) manifest apparently (any level of disease severity). This infection total is more than three times the dengue burden estimate of the World Health Organization. Stratification of our estimates by country allows comparison with national dengue reporting, after taking into account the probability of an apparent infection being formally reported. The most notable differences are discussed. These new risk maps and infection estimates provide novel insights into the global, regional and national public health burden imposed by dengue. We anticipate that they will provide a starting point for a wider discussion about the global impact of this disease and will help to guide improvements in disease control strategies using vaccine, drug and vector control methods, and in their economic evaluation.”
And, below is news of a practical dengue detection kit from the ICGEB, New Delhi. The text is from Professor Virander Chauhan, Director ICGEB Delhi. The ICGEB, amongst other places, is involved in a Dengue vaccine initiative. The one at ICGEB is led by Navin Khanna.
A Day 1 Dengue Detection Kit
Co-developed by J. Mitra& Co. and ICGEB New Delhi
Dengue disease may be asymptomatic or manifest symptoms ranging from mild fever to severe hemorrhage and shock syndrome, making clinical diagnosis difficult. Hence, a lot of emphasis is being made on the development of laboratory diagnostic methods which could enable quick and accurate detection of dengue. Timely diagnosis of this disease may prevent its progression to severe hemorrhagic conditions and death. Laboratory diagnosis of dengue may be based on isolation of virus, detection of viral genome, viral antigens or dengue-specific antibodies.
Currently, a number of kits are commercially available for the diagnosis of dengue on the basis of detection of IgG, IgM and NS1 antigen, either alone or in combination, using rapid tests (based on immune-chromatography) or ELISAs. Panbio Limited, Standard Diagnostics and BioRad have been the major players involved in the development of these kits.
An Indian company J. Mitra & Co Pvt. Ltd. in collaboration with International Center for Genetic Engineering and Biotechnology (ICGEB), New Delhi, has developed a test for the simultaneous detection of Dengue NS1 antigen and dengue IgM/IgG antibodies in human plasma/serum. This unique 3×1 combo rapid test provides a wider window of detection for dengue infection. This is very useful for the Indian settings where both primary and secondary dengue infections are co-prevalent. Further, the uniquely designed NS1 binder and reveal reagents used in the Dengue Day 1 test are highly cross-reactive between all 4 dengue virus serotypes, enabling detection of dengue infections irrespective of its serotype.
Dengue Day 1 Test is a rapid solid phase immuno-chromatographic test for the qualitative detection of Dengue NS1 Antigen and differential detection of IgM and IgG antibodies to Dengue virus in Human serum/plasma. This test is for in vitro diagnostic use only and is intended as an aid in the earlier diagnosis of Dengue infection & presumptive diagnosis between primary and secondary Dengue infection.
Dengue Day 1 test kit consists of two devices: one device for detection of Dengue NS1 antigen and second device for the differential detection of Dengue IgM/IgG antibodies in Human serum/plasma.
Dengue NS1 Antigen device contains two lines; ‘C’ (Control line) & “T” (Dengue NS1 Antigen test line). Test line is coated with anti-dengue NS1 Ag. When a sample is added to the device, Dengue NS1 antigen if present in the sample will bind to the anti-dengue NS1 gold colloidal conjugate making antigen antibodies complex. This complex migrates along the membrane to the test region and forms the visible pink line at “T” as antibody-antigen-antibody gold colloid forms.
Dengue IgM/IgG test device contains three lines; “C” (Control line), “M”(IgM test line) & “G”(IgG test line).IgM test line is coated with anti-human IgM and IgG test line is coated with anti-human IgG. When a sample is added to the device, IgG and IgM antibodies in the sample react with anti-human IgM or IgG antibodies coated on the membrane respectively. Colloidal gold complexes containing dengue 1-4 antigens is captured by the bound anti-dengue IgM or IgG on respective test bands located in the test window causing a pale to dark red band to form at the IgG or IgM region of the test device window.
First line testing kit for detecting dengue infection from day 1 using NS1 Antigen & differential detection of IgM&IgG Antibodies.
Diagnosis of both Primary & Secondary Infection.
Detects all 4 serotypes of Dengue virus.
Highly Sensitive & Highly Specific.
Long shelf life: 18 months at 2-30°C.
Convenient pack sizes: 10 Tests & 25 Tests.
Being sold in >40 countries in Asia and Africa.