RETROSPECTIVE ANALYSIS OF DENGUE VIRUS INFECTION: A FOUR-YEAR STUDY
Objective: To conduct retrospective surveillance study of dengue virus infection in patients presenting with febrile illness during 2015-2018.
Material and Methods: Dengue virus NS1 antigen and IgM antibodies were tested by ELISA method in serum samples of patients with febrile illness. Descriptive and analytical measures were used to assess the association of NS1 antigen and IgM antibodies with different risk factors like gender, age and month of the year.
Results: Over the period of four years (2015-2018), 2203 samples were received for dengue NS1 antigen. Out of these, 506 (23%) were positive and 1697 (77%) were negative. Among the positive samples, 162 (32%) were females and 344 (68%) were males, with significant association between NS1 antigen and gender (p<0.05). Similarly, 2089 samples were received for dengue IgM antibodies. Out of these, 389 (19%) were positive and 1700 (81%) were negative. Among positive samples, 128 (33%) were females and 261 (67%) were males (p<0.05). Moreover, significant association was observed for both NS1 and IgM cases with age. In addition, maximum number of positive patients for both NS1 and IgM were between 21-40 years of age. Most of the positive cases were detected during the months of July to October (p<0.05).
Conclusion: Dengue virus infection is a common cause of febrile illness in endemic countries like Pakistan. Male preponderance as well as high number of cases during rainy season were seen. Dengue infection was more prevalent among young people (21-40 years).
Key Words: Dengue, NS1, IgM.