The first outbreak of DHF was documented in 1994 by Chan and colleagues [21] who observed DEN-1 and DEN-2 in three out of ten tested patients for dengue virus. In the following year, DEN-2 infection was reported from the province of Balochistan [22, 23]. Through serological studies, dengue type 1 and type 2 were found in sera of children in Karachi [24, 25]. Jamil and colleagues [20] had previously been reported DEN-3 infection in 2005 outbreak of DHF in Karachi. Kan and colleagues [26] reported co-circulation of dengue virus type

2 and type 3 in 2006 outbreak in Karachi. More recently, Hamayoun and colleagues [22] reported cases with dengue infection in the 2008 outbreak in Lahore. Out of 17 samples checked via real-time PCR, ten of their patients had DEN-4,

five had DEN-2 and two click here had DEN-3 infection [22]. Pakistan has a history of outbreaks of dengue viral infection however, the responsible serotype/s MRT67307 datasheet is not well known. Therefore, the IWP-2 solubility dmso current study was initiated to determine the circulating serotype/s of dengue virus in Pakistan using molecular based techniques in patients’ sera. Samples were selected from stored repository from three most recent outbreaks of dengue virus (2007-2009) and the obtained sequences were compared to other dengue virus sequences reported from other geographical regions of the world to deduce a phylogenetic relationship. Results Serotyping of analyzed sample A total of 114 suspected dengue serum samples

along with demographic data were kindly donated by Gurki Trust Hospital Lahore and Sheikh Zayed Medical Complex Lahore for the current study. These samples were collected during three different mini outbreaks of dengue virus infection in years 2007, 2008 and 2009 and were stored at -20°C. Nested PCR was utilized for this serotype analysis. Out of total 114 tested serum samples, 20 were found positive for dengue virus RNA with various Amino acid serotypes. Table 1 shows the distribution of dengue virus serotypes in the study population. It is clear from the results of the current study that, of the 20 dengue virus positive samples, six had concurrent infection with two different dengue virus serotypes at a time generating data of 26 serotypes. Table 1 Total positive samples and dengue virus isolates included in this study. Year of isolation Total collected samples Positive samples Isolated serotype*       Serotype 2 Serotype 3 2007 41 5 4 1 2008 66 8 8 5 2009 7 7 7 1 Total 114 20 19 7 *Out of 20 positive samples, 6 samples had concurrent infection with two dengue virus serotypes giving a total of 26 dengue virus isolates. Nucleotide sequences analysis The amplified bands of each sample were gel eluted and were further used for sequence analysis. Junction of C-prM gene of dengue virus isolates was chosen for serotyping. Accession numbers of these 26 studied sequences are [GenBank: HQ385930-HQ385943 and HM626119-HM626130].