The sequences of infections which produced a higher risk of dengue fever upon secondary infection are: DEN1 followed by DEN2; DEN1 followed by DEN4; DEN2 followed by DEN3; and DEN4 followed by DEN3.
Several other vaccine approaches have been developed including live attenuated chimeric dengue vaccines (DENVax and LAV Delta 30), DEN protein subunit V180 vaccine (DEN1-80E) and DENV DNA vaccines.
There are five dengue viruses, called serotypes (DEN-1, DEN-2, DEN-3, DEN-4, and DEN-5), which belong to the Flaviviridae family and are transmitted to humans through infected mosquito bites, with the main vector the Aedes aegypti mosquito (Linnaeus, 1762).Studies performed with Ae. aegypti, aimed at their identification and analysis of their population structure, are fundamental to improve understanding of the epidemiology of dengue, as well for the definition of strategic actions that reduce the transmission of this disease.
The DENV assay results, in agreement with the serological tests and sequencing analysis, showed that the pathogen resulting in the DF explosion in Guangdong in 2006 belonged to DEN-1.
The results show that 45 people were positive for dengue-specific IgM (27 males and 18 females), while RT-PCR detected dengue viral RNA in 12 patients, 3 identified as DEN-1 and 9 as DEN-2.
To find fast and reliable methods to diagnose dengue in the early phase of the disease, patient acute-phase sera were investigated for the presence of dengue-specific immunoglobulin M (IgM) antibodies by enzyme-linked immunosorbent assay (ELISA) and also for dengue serotype (DEN-1 to DEN-4)-specific RNA by different PCR assays.
In 2001, an autochthonous case of dual viremia, resulting from naturally acquired dengue virus DEN-1 and DEN-2 infections was detected during the dengue outbreak that occurred in Barretos, a city with about 105,000 inhabitants in the North region of São Paulo State.
Conversely, HLA-B*51 was associated with the development of DHF in patients with secondary infections, and HLA-B*52 was associated with DF in patients with secondary DEN-1 and DEN-2 infections.
Using a serotype-specific monoclonal antibody (MAb) of dengue virus type 1 (DEN-1), 15F3-1, we identified the B-cell epitope of DEN-1 from a random peptide library displayed on phage.
During the observation period, primary dengue infection rates were DEN 1 = 4.8%, DEN 2 = 7.7%, DEN 3 = 4.2%, and DEN 4 = 3.4%, while two or more dengue infections occurred in 6.7% of the study population.
A split decomposition analysis of dengue (DEN) virus gene sequences revealed extensive networked evolution, indicative of recombination, among DEN-1 strains but not within serotypes DEN-2, DEN-3, or DEN-4.
Four recombinant vaccinia viruses expressing different portions of the dengue type 1 virus (DEN-1) genome (C-prM-E-NS1-NS2A-NS2B; prM-E; prM-E-NS1-NS2A-NS2B; or NS1-NS2A) were constructed in order to establish the most immunogenic configuration of DEN-1 proteins.