Chikungunya virus (CHIKV) has re-emerged in Asia with increasing pediatric involvement, yet systematic data from mainland China remain limited. Global climate change has further facilitated the spread of Aedes-borne viruses in the Asia-Pacific region1. Although joint manifestations are well described in adults, pediatric patterns, especially those supported by imaging, are less commonly reported in China2. CT values offer a semi-quantitative indicator of viral replication^], while ultrasonography is sensitive for detecting acute synovial inflammation4. However, few studies have integrated these indicators in children. Here, we briefly report clinical features, ultrasonographic findings, and virological correlates in 42 pediatric Chikungunya cases, representing one of the first integrated pediatric datasets from southern China. This retrospective analysis included 42 laboratory-confirmed CHIKV infections admitted to Foshan First People’s Hospital, Foshan, Guangdong, China, between July and August 2025. Similar to previous pediatric cohorts describing acute febrile rash illness5, 6, our inclusion criteria required laboratory confirmation by RT-PCR, and children with co-infections or rheumatologic disease were excluded. Demographic characteristics, clinical manifestations, laboratory parameters, CT values, and joint ultrasonography were retrieved from electronic medical records. Ultrasonography was performed within 72 h after admission by trained radiologists using a high-frequency (7-12 MHz) linear probe, consistent with recommended musculoskeletal imaging practices4. The institutional ethics committee of Foshan First People’s Hospital approved this study Approval No. Lunshenyan (2025) 220; July 11, 2025, and informed consent was obtained from guardians. Among the 42 children mean age, (10. 2 ± 4. 1) years; 23 boys, fever (95. 2%) and rash (100%) were universal features, consistent with prior pediatric cohorts reporting near-universal exanthem5, 7. Arthralgia occurred in 28 children (66. 7%), typically mild to moderate (mean VAS: 2. 6 ± 1. 3), and most often involved the ankles and wrists. Table 1 summarizes demographic and clinical characteristics, including the distribution of joint involvement. Table 1: Demographic and clinical characteristics of 42 children with Chikungunya fever. Ultrasonography demonstrated abnormalities in 20/24 (83. 3%) children with arthralgia, whereas none of the 14 cases without arthralgia showed abnormal findings (P<0. 001). These results echo previous observations that CHIKV-related synovitis and effusion are prominent during the acute phase4, 8. Lymph-node abnormalities were also more frequent in children with arthralgia (45. 8% vs. 0%, P=0. 002), suggesting broader immune activation similar to that described in other pediatric reports9. Importantly, CT values showed a significant negative correlation with the cumulative number of affected joints (Spearman r=−0. 47, P=0. 002), indicating that higher viral loads correspond to broader joint involvement (Figure 1). A similar relationship between viral load and musculoskeletal inflammation has been described in adult studies8. Figure 1 illustrates this association. Among the 16 children who underwent repeat testing before discharge, 62. 5% achieved viral negativity within 3-5 days, while others showed rising CT values, indicating a reduction in viral activity during recovery. Figure 1: Correlation between viral CT values and cumulative number of affected joints in pediatric CHIKV infection (Spearman r=−0. 47, P=0. 002). This report has several limitations: it is a single-center retrospective study with a modest sample size, and not all children underwent ultrasonography. Cytokine or immunologic profiling was not performed, although previous research highlights distinct inflammatory pathways in pediatric Chikungunya, including IL-6 and TNF-α elevation9. Nevertheless, this brief report provides quantitative evidence linking viral load with ultrasonographic abnormalities in children. Integrating molecular markers with bedside ultrasonography may facilitate early risk identification and strengthen regional pediatric surveillance strategies where Aedes-borne viruses continue to expand1, 2. In conclusion, pediatric Chikungunya in southern China is characterized by high frequencies of rash, fever, and arthralgia, with strong correspondence between symptoms, ultrasonographic abnormalities, and viral CT values. CT values may serve as early markers of inflammatory burden, supporting their integration into pediatric assessment frameworks in endemic regions. Conflict of interest satement The authors declare that there are no conflicts of interest. Funding The authors received no extramural funding for the study. Authors’ contributions M. T. conceived and designed the study, collected the clinical data, performed the analysis, and drafted the manuscript. W. Z. , X. C. , and G. L. contributed to data collection and data curation, and assisted in data analysis and interpretation. K. L. E. H. and A. K. C. L. provided critical revision of the manuscript for important intellectual content. S. J. supervised the project and coordinated the study. All authors reviewed and approved the final version of the manuscript. Publisher’s note The Publisher of the Journal remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Edited by Zhang Q, Lei Y, Pan Y
Tan et al. (Sun,) studied this question.