Pramod Sidram Manthalkar1, Basawaraj V Peerapur2
1Department of Microbiology, BLDEU’S Shri B M Patil Medical College, Bijapur, Karnataka, India
2Department of Microbiology, RIMS, Raichur, Karnataka, India
Introduction: Dengue fever is a mosquito-borne disease caused by flavivirus and has clinical presentation varying from being asymptomatic to severe complications (dengue shock syndrome and dengue hemorrhagic fever) depending on the serotype of the virus involved. Cross-protective immunity between the serotypes is lacking, hence the severity of the disease is more if multiple infections occur with two different serotypes. Hence, data on the demographic-specific prevalence of virus serotypes are vital to optimal clinical measures. Aim: The present study aimed to identify the dengue virus serotypes prevalent in the North Karnataka region of India in correlation to the clinical presentation of the disease. Materials and Methods: A prospective study was carried out in a Teaching hospital of North Karnataka, India, from June 2012 to March 2016. One thousand serum samples were tested for NS 1 antigen aIgM and IgG antibodies by enzyme-linked immunosorbent assay (ELISA) method. Samples positive for NS-1 was subjected to reverse transcription polymerase chain reaction (RT-PCR) for the detection of serotypes. Results: Of the 1000 serum sample test 462 serum samples were positive for dengue virus antigen or antibodies. Two hundred and forty-five patients (53.03%) were male and 217 patients (46.96%) were female. Age group of16-–30 years was more affected followed by 31–45 years, over 45 years, and 0–15 years of age group. Maximum number of cases were observed in Bidar city followed by Humnabad, Aurad, Bhalki, and Basavakalyan regions. Malaise was a predominant symptom in dengue virus serotype-3 (DENV-3) (P < 0.05), while headache (P < 0.001), and retro-orbital pain (<0.05) were predominant symptoms in DENV-2. GI symptoms (nausea, abdominal pain, and diarrhea) were significantly common in DENV-2 (P < 0.001). Hepatomegaly was frequently observed in DENV-2 (17.02%), (P < 0.05). A total of 462 samples were positive for either NS-1, IgM, or IgG or in combination. Viral RNA was extracted from 119 samples positive for NS-1 antigen by ELISA. Of the 119 samples tested for serotyping by RT-PCR, 38 belonged to dengue serotype-1 (DENV-1), 46 were of dengue serotype 2 (DENV-2) and 35 belonged to dengue serotype 3 (DENV-3). A change in the earlier serotype 1 and 2 from 2011 to 2013 to the present serotype DENV-2 and DENV-3 was observed and constant presence of DENV-2 in circulation was recorded. Conclusion: Dengue virus serotype 1, 2, and 3 were prevalent in our study population, and severe clinical manifestations were observed in patients suffering from dengue virus serotype 2 and 3.
Keywords: Dengue, North Karnataka, serotype.