Serological & Molecular Characterization of Dengue Virus in a Tertiary Care Hospital of North Karnataka.

Abstract

Dengue is a viral disease, caused by Flavivirus, transmitted by mosquito vector. Dengue virus infection may vary from mild Dengue fever to severe complications like, DHF and DSS. Dengue fever is the major cause of high mortality and morbidity in Tropical and Subtropical regions. 50 to 100 million people are affected every year globally. Dengue virus is a RNA virus and has got four different serotypes. Dengue presents with Fever, Arthralgia, Retro-orbital pain, Myalgia and in severe cases it may present with Nausea, Vomiting and bleeding tendency. Severity in dengue infection is because of the partial protection against the other serotypes and in multiple serotype infection the antibody dependent enhancement of the infection is seen. Laboratory diagnosis plays an important role in diagnosis of disease, which may help in proper treatment and immediate action, as there is no treatment available and vaccines are still under trial. There are various methods for detection of the Antigen and Antibodies of dengue virus in patient’s serum, which may help in diagnosis of the disease. This study was aimed to detect the incidence of the Dengue virus infection and to evaluate the proper dengue diagnostic test and to know the incidence of multiple serotype infection. Material and Methods: 1000 Dengue suspected patients as per WHO criteria were considered, serum samples were collected from the patients and subjected for the detection of Antigen and antibodies by rapid and ELISA method, all the NS-1 positive serum samples were subjected for detection of the viral RNA, serotyping was done to know the serotype present in the serum.Result: Out of 1000 samples, 462 serum samples were positive for Ag or Ab or both by rapid or ELISA. All the serum samples were subjected for testing by Rapid card method and ELISA. Male patients were more infected compared to women but significant difference was not observed. Age groups of 15-30 years were more infected followed by 30-45 age groups. More number of Dengue cases were seen in the month of October i.e. Post monsoon months, cases started in the month of June and ended in December. More number of cases was from Bidar city followed by Humnabad, Bhalki, Aurad and Baswakalyan. All the patients were suffering from fever, followed by headache, myalgia, body ache, arthralgia, nausea, vomiting and abdominal pain. All the NS-1 positive samples were subjected for RT PCR for the detection of the Dengue virus serotype. DENV-1, 2 and DENV3 were identified from the samples and detailed clinical correlation was done. Conclusion: ELISA is the most useful tool for detection of Dengue virus antigen or antibodies from patient’s serum. DENV-1, DENV-2 and DENV-3 are circulating with changing trend of serotype was observed, with severe clinical features in DENV-2 and 3 serotype infection. Serotype-1 showed unique conserved site Nco1.