The region of C-prM gene junction was selected for serotyping as the region is not very hyper variable and most of the mutations reported are of silent type [12]. Lifecycle HKI-272 mw of dengue virus involves both human and mosquitoes and this might be the reason for low rate of variation among dengue virus as compared to other RNA viruses. According to several reports, the classification of dengue genotypes is based on less than 6% of nucleotide

divergence within a selected genomic region [12, 28]. Dendrograms were drawn to study the evolutionary history of the sequenced serotypes as well as their genotypes which showed that serotype 2 circulating in 2007-2009 belonged to genotype IV. Strains from Northern India, China and Indonesia also fall in this subtype [12]. No particular pattern of genotype distribution can be inferred for serotype 2 as different genotypes spread in diverse locations. Raf inhibitor For serotype 3, only sequences of capsid region from genotype I and III are reported. So the tree was created using global sequences of genotype I and III only. However, the tree visibly shows that the studied serotype 3 has genotype III. It is clear from the findings of our study that there is no definite pattern of distribution of subtype III of dengue virus 3 worldwide [4]. The previously sequenced three strains from Karachi (Pakistan)

in 2005 [20] also have same genotype emphasizing the fact that genotype III of dengue virus 3 prevails in Pakistan. There is not much data available from Pakistan on serotypes of dengue virus; this study is the first one to characterize serotypes 2 and 3 in their respective subtypes. The only limitation of this study is small number of sequenced samples. There is a need for more randomized and multi-analysis studies to be conducted on serotyping and subtyping of different dengue strains in Pakistan; in this way a

clearer view on spread of dengue virus can be made. Conclusions Based on the findings of the current study we conclude that the predominant serotypes Parvulin of dengue virus circulating in Pakistan are 2 and 3. Ample number of cases with mixed serotypes (serotype 2 and 3) are seen and might be common in all regions of this country. The major genotypes circulated in the study period are subtype IV of dengue virus 2 and subtype III of dengue virus 3. check details Methods Patients Samples and Extraction of viral RNA A total of 114 serum samples were received from Gurki Trust hospital Lahore and Sheikh Zayed Medical Complex Lahore. Viral RNA was extracted from 140 μl of serum sample using Nucleospin Viral RNA Extraction Kit (Macherey-Nagel, Germany) with slight modifications. Briefly, 600 μl of lysis buffer was added to 140 μl of serum sample and vortexed for few seconds. Then the samples were incubated at 70°C for 5 minutes. Then 600 μl of absolute alcohol was added. The sample was loaded in the column tube and centrifuged at 13000 rpm for one minute. A 500 μl of buffer RAW was added and centrifuged at 13000 rpm for 5 minutes.