To determine the prevalence of primary and secondary infections among the clinically suspected cases of dengue

Abstract

Background: Dengue is currently regarded globally as the most important mosquito borne viral diseases presenting with varied symptomatology. Epidemiology and clinical presentation of dengue infection differs significantly across geographical areas in India. Aim: To determine the prevalence of primary and secondary infections among the clinically suspected cases of dengue. Material and methods: This was a prospective observational study conducted in the Department of Microbiology Nalanda Medical College and Hospital,Patna,Bihar, India from Oct 2019 to may 2020. A total of 600 serum samples from suspected dengue cases attending OPD or admitted in the hospital were tested for the confirmation of Dengue. We have received blood samples in our microbiology laboratory, the blood samples were allowed to clot at room temperature and then we centrifuged the samples and serum samples were separated. From the serum samples we have done NS1 Ag and IgM Ab testing by ELISA. Results: Out Of 600, 120 samples were positive for dengue. Seroprevalence of Dengue was 20%.80 (66.67 %) were male patients and 40 (33.33 %) were female patients. 88(73.33%) patients were from urban area and 32(26.67%) from rural area. The dengue infection was observed more (28.33%) in the age group 20 to 30 years followed by 10 to 20 years (25.83%) and 30 to 40 years (22.5%).All dengue positive patients in our study had fever of 2 to 7 days. The most common presenting symptoms of dengue were fever with body ache (45.83%), headache (37.5%), nausea 34.17%) and vomiting (24.17%) and fever with rash was observed in 9 cases(7.5%). Out of 120 dengue cases, NS1/NS1+IgM/IgM were positive for 103(85.83%) patients, suggesting primary infection. IgM and IgG positive was seen in 8(6.67%) patients, suggesting late primary or early secondary infection. IgG was positive in 9(7.5%) cases, suggesting secondary or past infection. Thrombocytopenia (<1,00,000/mm³) was observed in 45(37.5%) cases. In 7(5.83%) patients platelet count was< 20,000/mm³. Conclusion: Effective implementation of vector control measures through efforts toward vector breeding source reduction help in reduction of the dengue prevalence in community. This prevention measures will be helpful to us for decreasing other vector borne diseases simultaneously.

Keywords: Dengue, NS1 antigen, IgM antibody, Seroprevalence.