Neonatal Dengue Infection Mimicking Late-Onset Neonatal Sepsis in Endemic Regions: A Case Report Series and a Proposed Diagnostic Framework for Antimicrobial Stewardship.

Neonatal dengue infection may mimic late-onset neonatal sepsis (LOS) in endemic regions, leading to misdiagnosis and unnecessary antibiotic exposure. We describe a case series of neonates admitted to a tertiary referral hospital in a dengue-endemic area with suspected LOS who underwent standard sepsis evaluation, including blood cultures, inflammatory markers, and clinical assessment, and were subsequently tested for dengue infection by anti-dengue virus IgM using ELFA methodology on the VIDAS® platform. All patients presented with fever and hematologic abnormalities, particularly thrombocytopenia and/or leukopenia, while blood and urine cultures remained negative and procalcitonin levels were low or normal. Dengue IgM was positive in all cases, supporting the diagnosis of neonatal dengue infection. After diagnostic confirmation, antibiotics were discontinued when applicable, and all neonates had favorable clinical outcomes without complications at discharge. These findings highlight dengue as a potentially underrecognized differential diagnosis of LOS in endemic settings and suggest that arboviral testing may be considered in the diagnostic evaluation of neonates with suspected sepsis, particularly when cultures are negative and inflammatory markers are not suggestive of bacterial infection. Early recognition may help reduce unnecessary antimicrobial exposure and could support antimicrobial stewardship efforts.