**4.1.8 Study sample characteristics**

Eight studies were conducted in the hospital settings (Zhang, C. et al 2006, Rico-Hesse R. et al. 1998, Wittke,V.et al.,2002, Kukreti, H. et al.,2008;Dash, P.K.et al.,2006, Islam, M.A.et al.,2006, al,Kanakaratne, N. et al.,2009), three in the community (Zhou Y, et al 2006, Dash PK, et al 2006, Kanakaratne, N. et al.,2009), where as data was extracted from laboratory records in two studies (Jamil B, et al, 2007, King, C.C. et al.,2008) and dengue virus strain were taken from frozen stock of clinical serum samples in two (18, 21).

Age ranges for dengue patients in these studies varied from 1 year to 70 years. The total numbers of dengue patients were 7663 in these studies. Characteristics of the studies included in this review have been summarized in table 2. A total of 285 virus isolates were subjected to genotyping/ sequence analysis in these studies. All four genotypes were studied in three studies (Zhou Y, et al 2006,Jarman RG, et al 2008, Rico-Hesse R. et al. 1998); only DEN 3 in five studies (Wittke,V.et al.,2002, Kukreti, H. et al.,2008; Islam, M.A.et al.,2006), only DEN 2 in three studies (Zhou Y, et al 2006,Mangada MNM et al 1997, Zhang, C. et al 2006), only DEN 4 in one studies (KlungthongC, et al, 2004), whereas DEN 1 and DEN 3 in one study (Kukerti H, et al 2008) and DEN 1, DEN 2 and DEN 3 studied in one study (Jarman RG et al 2008).
