Background Chikungunya is a mosquito-borne re-emerging disease that has caused a significant number of outbreaks recently in diverse geographic settings across the globe. It leads to severe debilitating illness in a significant proportion of persons who are infected. Measures to limit the impact produced by recurrent outbreaks of the disease are limited and there is an urgent clinical need for early identification of those predisposed to develop severe disease. A comprehensive understanding regarding the proportion of individuals predisposed to developing severe disease is lacking as its correlation with detectable viremia is hinted at by some studies. In this context, we hypothesized that detectable viremia reflected in the diagnostic RT-PCR assay could be significantly associated with the development of severe disease in Chikungunya among those diagnosed on the basis of seroconversion. Our study aims to confirm the same in relation to disease severity among the suspected patients of Chikungunya in the setting of a tertiary care center. Methods In a prospective observational study at a tertiary care center, a total number of 1021 Chikungunya suspects presenting within seven days of illness were screened with Chikungunya Virus IgM ELISA from 2021 to 2023. Those having positive IgM results were further tested with RT-PCR in a blinded manner. According to the information entered into the predesigned form and the hospital follow-up/discharge data, the cases where symptoms like fever and joint pain persisted beyond two weeks were classified as severe versus those resolving within two weeks as mild. The patients in each group were compared for their clinical symptoms and association with the disease severity with detectable viremia (RT-PCR positivity). Results We identified a total of 178 (17.4%) lab-confirmed Chikungunya IgM-positive cases amongst the recruited patients. Here a total of 31 (18.9%) cases could be classified as severe and 133 (74.7%) as mild illness, the remaining 14 patients were excluded from analysis due to insufficient clinical data. Severe illness was significantly higher in elderly individuals belonging to more than 60 years (p = 0.01). Viremia was detected in 16 (9%), those with detectable viremia had higher odds (OR = 4.1) of manifesting as severe disease. Among the severe cases, the proportion of cases with RT-PCR positivity (8, 25.8%) at presentation was significantly higher (P = 0.01) versus those who presented with mild disease (7, 5.5%). Conclusion Our study reveals a correlation between detectable viremia in Chikungunya virus (CHIKV) patients and an increased risk of manifesting into a severe disease, where severe cases exhibited a significantly higher proportion of viremia, indicated by RT-PCR positivity. This study hints at the presence of viremia, joint symptoms, and elderly age as potentially useful clinical predictors of disease outcomes, these may serve as indicators for closer monitoring among individuals seeking medical attention due to Chikungunya infection. However, we need to validate these findings in future longitudinal studies incorporating multiple, time-bound follow-up data on clinical outcomes, viral titers, and its long-term complications.
Keywords: chikungunya virus (chikv); clinical severity; molecular testing; poly-arthralgia; reemerging; viral serology; viremia.
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