Dengue virus serotypes and epidemiological features of dengue fever in Faisalabad, Pakistan

Dengue infection has become a major public health threat in Pakistan, causing several outbreaks from 1994 to 2012. This cross-sectional study was carried out to determine viral serotypes responsible for major outbreak of dengue fever in Faisalabad, Pakistan during 2011. Total 50 patients (37 males and 13 females) reported within 2-4 days of onset of fever, positive for dengue NS1 antigen, were recruited for this study. The median age of the patients was 29 years. Laboratory findings indicate thrombocytopenia in 92.0%, decreased hemoglobin in 48.0%, and leukopenia in 38.0% patients at the time of admission. Liver enzymes were elevated in 100.0% patients. ALT levels were 7.0 times higher, while AST levels were 7.3 times higher than the normal values in dengue patients. Molecular epidemiology of the dengue fever revealed co-circulation of three different DENV serotypes in Faisalabad population. Among them 82.4% were positive for DENV2; 5.8% with DENV3; and 11.7% were reported with DENV4. Co-circulation of three different DENV serotypes in the city is an alarming situation, which could result in a more severe outbreak of DF (DHF/DSS) in the future.