Incidence of dengue, chikungunya, malaria, typhoid fever, scrub typhus, and leptospirosis in patients presenting with acute febrile illness at a tertiary care hospital, Amritsar.

Background Objectives: India is both a tropical and subtropical region, where common causes of acute undifferentiated febrile illness (AUFI) include malaria, dengue fever, chikungunya fever, enteric fever, leptospirosis, scrub typhus, and Japanese encephalitis. These illnesses contribute significantly to patient morbidity and mortality, although the exact burden of each infection varies regionally. Given the high prevalence of these tropical diseases, prioritizing differential diagnoses in cases of AUFI is crucial. In recent years, dengue, chikungunya, malaria, typhoid fever, scrub typhus, and leptospirosis along with coinfections between these diseases have reemerged as major causes of AUFI in many parts of India. These diseases are the most frequent contributors to AUFI and significantly increase patient morbidity and mortality compared to other causes. Although leptospirosis is not endemic in Punjab, cases are still screened as part of the National Centre for Disease Control (NCDC) National One Health Programme for Prevention and Control of Zoonoses (NOHPPCZ). Additionally, as a tertiary care hospital, the facility receives patients from migratory populations and other states beyond Punjab, thereby addressing a broader range of cases. To determine the incidence and clinical profile of dengue, chikungunya, malaria, typhoid fever, scrub typhus, and leptospirosis among patients presenting with acute undifferentiated fever admitted to the Department of Medicine at GNDH Tertiary Complex, Amritsar.

Methods: The present study was conducted in the Viral Research and Diagnostic Laboratory, Department of Microbiology, Government Medical College, Amritsar, over a 12-month period from January 1, 2023, to December 31, 2023. A total of 276 patients aged over 18 years with acute undifferentiated febrile illness (AUFI) presenting to the inpatient services of the Medicine Department at Government Medical College, Amritsar, during the study period constituted the study population. The demographic and clinical profiles of the cases were recorded using a predesigned pro forma. Rapid immunochromatographic tests and enzyme-linked immunosorbent assays (ELISA) were performed on blood samples to identify active infections of dengue, chikungunya, scrub typhus, leptospirosis, typhoid fever, and malaria.

Results: The overall incidences of dengue, chikungunya, malaria, typhoid fever, scrub typhus, and leptospirosis among AUFI cases were 11.6% (32/276), 24.6% (68/276), 0.7% (2/276), 5.4% (15/276), 1.4% (4/276), and 8.7% (24/276), respectively. The incidence of coinfected cases among AUFI cases was 15.6% (43/276). The most common coinfection was dengue + chikungunya, observed in 26 cases, followed by dengue + leptospirosis in 6 cases, leptospirosis + scrub typhus in 4 cases, chikungunya + typhoid fever in 3 cases, chikungunya + malaria in 2 cases, and leptospirosis + typhoid fever in 2 cases. The incidence of dengue, chikungunya, malaria, typhoid fever, scrub typhus, and leptospirosis was slightly higher among females (34.4%) compared to males (33.7%). Fever accompanied by myalgia was the most common presenting complaint in all cases.

Interpretation Conclusion: The most significant etiological agents of AUFI in our investigation were chikungunya, followed by dengue, leptospirosis, typhoid fever, scrub typhus, and malaria. The high incidence of co-infections (15.6%) observed in our study reflects an undefined level of previous infections, cross-reactivity, and subclinical infections within the population. As the majority of tropical infections are location-specific yet clinically indistinguishable, regional knowledge and the use of commonly available serological tests are essential for the timely detection of other etiological agents of AUFI.