Detection of probable hantavirus infections in clinically suspected dengue patients in a tertiary care hospital in Sri Lanka.

Background: Acute febrile illnesses, including dengue fever, are common causes of hospitalization in Sri Lanka. However, a significant proportion of clinically suspected dengue cases tested negative for dengue-specific markers, raising concerns about alternative infectious causes such as hantavirus. This study aimed to detect hantavirus infections among patients clinically suspected of dengue who tested negative for dengue NS1 and IgM antibodies and to analyze the epidemiology of hantavirus infections in febrile patients.

Methodology: A descriptive cross-sectional study was conducted at the Department of Virology, National Hospital Kandy, from January to August 2023. A total of 415 serum samples from clinically suspected dengue patients who tested negative for dengue NS1 and IgM antibodies were selected. Hantavirus detection was performed using real-time RT-PCR and IgM antibody testing. Additional tests for flavivirus, alphavirus, and leptospirosis were also conducted. Demographic, clinical, and laboratory data were collected from hantavirus-positive cases.

Results: Among the 415 samples, 21 (5.1%) tested positive for hantavirus IgM antibodies. None of the samples tested positive for hantavirus RNA. The demographic analysis revealed no significant difference in age or gender between hantavirus-positive and negative patients. Co-infection with leptospirosis was observed in one patient. In addition to fever, clinical features of hantavirus infection included dry cough (41.2%), vomiting (35.3%), and shortness of breath (23.5%). Laboratory findings showed elevated liver enzymes (AST: 61.5%, ALT: 53.8%), elevated creatinine (50%), and elevated CRP (72.7%).

Conclusion: The putative 5.1% hantavirus seropositivity rate among clinically suspected dengue patients suggests that hantavirus should be considered in differential diagnoses. Although no hantavirus RNA was detected, the presence of IgM antibodies and negativity to other potential infections indicates a potential recent infection or probable cases. The study highlights the challenge of diagnosing hantavirus due to its similar presentation to dengue fever and the need for improved diagnostic testing. Early diagnosis and tailored management can improve patient outcomes and guide public health responses. Further studies and expanded diagnostic capabilities are recommended to better understand hantavirus prevalence and to improve clinical care for affected patients.