Plaque Characteristics of Circulating Chikungunya Virus Clinical Isolates Correlate With Initial Viral Load, Antibody, and Immune Mediators as Indicators of Disease Outcome

Chikungunya virus (CHIKV) infection poses a worldwide health risk and negatively impacts the well-being of those infected for an extended period. Understanding the characteristics of the circulating virus within the population and its virological, immunological, and molecular aspects is essential for developing effective control measures and improving disease management. The current study assessed 69 clinical CHIKV isolates obtained from acute serum samples collected from patients across India between 2016 and 2022. CHIKV was successfully isolated from 69 acute serum samples, and plaque size/morphology and the growth kinetics of the clinical isolates were analyzed. The findings indicated that there was a significant correlation between the plaque size of CHIKV isolates and the virus's growth kinetics, viral load, and immune response, all of which may affect disease outcomes. Specifically, larger plaque variants were associated with more severe symptoms and faster recovery from the disease, whereas smaller plaque variants were linked to persistent arthralgia and a greater likelihood of chronic disease. These findings highlight the potential of using plaque size as a predictive factor for disease progression and emphasize the importance of considering plaque morphology in CHIKV disease outcome studies.