Title : The hidden burden of human parvovirus B19 infection among patients with suspected dengue fever
Abstract:
Acute febrile illnesses in tropical countries are commonly attributed to dengue infection; however, other viral pathogens such as Human Parvovirus B19 (B19V) may present with similar clinical and hematological manifestations, leading to diagnostic challenges and possible misclassification. This study aimed to determine the prevalence of Human Parvovirus B19 infection and its co-infection with dengue among patients clinically suspected of dengue fever and to evaluate its association with clinical and laboratory features. A cross-sectional study was conducted from November to December 2025 at Sri Ramachandra Medical College & Research Institute (SRMC&RI), Chennai (IEC: CSP/25/OCT/169/544). A total of 105 anonymized residual serum samples from patients suspected of dengue fever were included. After routine dengue testing, post-diagnostic sera were stored at −20°C and tested for Human Parvovirus B19 IgM and IgG antibodies using commercial ELISA kits (NovaLisa®, Novatec, Germany) according to the manufacturer’s instructions. Optical density values were converted to NovaTec Units (NTU) using the formula NTU = (sample absorbance/cut-off absorbance) × 10, with NTU >11 considered positive and <9 negative. Among the 105 patients (age range: 10 months–86 years), B19V IgM and IgG antibodies were detected in 27.6% (n=29) and 28.6% (n=30), respectively, with overall seropositivity observed in 43.8% (n=46). Based on serology and clinical correlation, 27.6% of patients were classified as having active B19V infection, while 6.7% had dengue–B19V co-infection. Fever was the most common clinical symptom (72.4%), followed by chills and vomiting, while anemia (37.9%) and thrombocytopenia (17.2%) were frequently observed hematological abnormalities. Co-infected patients demonstrated higher rates of hematological abnormalities, suggesting increased clinical severity. These findings highlight the under-recognition of Human Parvovirus B19 in patients presenting with dengue-like illness and support its consideration in the diagnostic evaluation of acute febrile illnesses to improve accurate diagnosis and patient management.
