Occurrence of Dengue Virus Infection with Multiple Serotypes in Central Karnataka, India.

Objective  To find the incidence of concurrent infection of dengue and correlate the difference in clinical features, laboratory diagnoses, and outcomes between dengue and dengue-like illnesses. Methodology  A total of 2,256 patients with suspected dengue fever during the period of July 2014 to June 2020 as per the WHO case definition for dengue fever were enrolled in the study. All patients admitted with a suspected dengue fever were studied in detail in terms of demographic features, clinical features, and laboratory profiles. Two blood samples were collected from each patient with a history of fever for 5 to 7 days. Investigation consisted of CBC, Widal test, malarial card test, Weil Felix test, Scrub typhus test, chikungunya, dengue parameters such as dengue NS1, IgM, and IgG, and real-time PCR for dengue serotypes were performed for each sample. Results  A total of 1,412 males (62.6%) and 844 females (37.4%) of age 2 to 44 years were hospitalized. Out of 2,256 clinically suspected dengue cases, 1,306 cases were positive and 950 were negative by RT-PCR test. Fever was the most common clinical features among the RT-PCR-positive cases, followed by retroorbital pain (85.9%), flushing in 77.5%, and rashes in 84.8% of patients. ARDS was seen in 9.7% and splenomegaly in 27.5% patients. A platelet count of less than 100,000 was observed in 1,838 (81.5%) patients, and a platelet count of less than 20,000 was observed in 147 (6.5%) patients. Of 2,256 samples, 1,306 (57.9%) tested positive for dengue viral RNA by RT-PCR. Also, 798 cases were infected with a single DENV serotype, and 608 had a concurrent infection. Of the 798 single DENV serotype infection cases, 392 (54.2%) were typed as DENV-2 and 218 (29.2%) as DENV-3. Coinfection with serotypes DENV-2 and DENV-3 was found to account for 67.8% of all concurrent infections. Conclusion  The study showed that dengue fever with concurrent infection with multiple serotypes is on the rise, and an occurrence of recombination may lead to the emergence of more virulent strains showing varied clinical presentations.