Dengue virus serotype 2 and 3 causing high morbidity and mortality in Swat, Pakistan

Dengue, an alarmingly growing epidemic viral disease is a major health concern. Pakistan suffered several
mini and major outbreaks of dengue over the past couple of years with high morbidity rates than those
commonly reported from dengue epidemics globally. Hundreds of people died in the string of dengue
epidemics in Pakistan since 2005. In July 2013, a major outbreak of dengue started in Swat district of Khyber Pakhtunkhwa (KPK) which has so far caused 57 deaths and thousands of morbidities. In this study, we screened 414 clinically diagnosed dengue patients for dengue specific antibodies, out of which 366 were found to be serologically positive by the Standard Diagnostics (SD) Dengue Duo test. All dengue virus (DENV) positive samples were then analyzed using a DENV serotype-specific reverse transcriptase polymerase chain reaction to identify the DENV serotypes present and to figure out active infections. In this study, 28.69% (105/366) of the serologically positive patients had active infection and DENV type 3 (DENV-3) was the most abundant serotype followed by DENV-2; similar to the outbreak in Punjab during 2010-11. The mortality rate from this epidemic to date has however been lower compared to the previous major DENV outbreak of 2010-11 in Lahore.