Identification of prevalent dengue serotypes by reverse transcriptase polymerase chain reaction and correlation with severity of dengue as per the recent World Health Organization classification (2009)

ABSTRACT

Context A definite link between distinct dengue serotypes and severe clinical manifestations has not been established yet. The WHO classification (2009) of dengue is more competent in diagnosing severe cases compared to traditional (1997) classification. Aims: This study aimed to identify prevalent dengue serotypes and to correlate the severity of dengue with the dengue virus (DENV) serotypes in target population as per the recent WHO classification (2009). Settings and Design: A retrospective comparative observational study was conducted from 1st January 2015 to 31st December 2015. Subjects and Methods: We tested 242 dengue NS-1 antigen ELISA-positive cases for serotyping by dengue reverse transcriptase-polymerase chain reaction (RT-PCR). Severity of each dengue case confirmed by RT-PCR was determined as per the recent WHO classification (2009). Results: On the basis of RT-PCR, dengue infection was confirmed in 135 (55.78%) patients. DEN-3 was the most common serotype found in 71 (52.6%) patients, followed by DEN-2 serotype with 44 (32.6%) patients. Nearly 2.22% cases of DEN-2 and 2.96% cases of DEN-3 serotype were having dengue with warning signs. Severe dengue was found in 2.22% cases of DEN-2 and 5.18% cases of DEN-3 serotypes. Thrombocytopenia, haemorrhagic manifestations and atypical presentations were found most commonly in DEN-3 followed by DEN-2 serotype. Coinfection with more than one serotype was observed in our study, with the most common coinfection pattern being DEN-2 and DEN-3 serotypes. Conclusions: DENV-3 and DENV-2 serotypes are prevalent in the region and are associated with a more serious clinical profile than other serotypes.