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Chikungunya fever is an acute arboviral illness caused by the Chikungunya virus (CHIKV), its infection mainly causes fever, myalgia, and skin rash. The first documented outbreak of Chikungunya fever occurred in the Newala district of Tanzania, East Africa in 1952. As early as October 2010, an outbreak of chikungunya fever had occurred in Guangdong Province 1. Now, CHIKV is widely spread worldwide from Africa to tropical/subtropical regions worldwide and becomes a global public health problem 2. A recent recurring outbreak of Chikungunya fever (CHIKF) in Foshan City, Guangdong Province, China, has drawn significant public health attention. Since the first imported case was detected in Shunde District on July 8, confirmed cases have rapidly spread across multiple districts. As of September 13, 2025, a total of 10,873 CHIKF cases have been reported 3. Fortunately, all cases have been mild, with no severe outcomes or fatalities. The outbreak prompted a swift response. Local surveillance systems quickly identified the index case, gaining crucial time for mitigation. In 53 hospitals, in-house polymerase chain reaction (PCR) testing was rapidly implemented, enabling same-day sample collection, reporting, and public health intervention. This timely action, coordinated with the Center for Disease Control and Prevention, played a key role in containing the spread of the disease. The response in Foshan underscores the importance of early detection and reporting in managing vector-borne diseases. CHIKF is primarily transmitted by Aedes mosquitoes, particularly Aedes aegypti and Aedes albopictus. The rapid spread of the virus is closely linked to mosquito density and the speed of case detection 4, 5. Multiple hospitals in Foshan began routine PCR testing, incorporating viral nucleic acid screening into standard diagnostic protocols. This facilitated rapid case confirmation, enabled effective epidemiological tracing, and supported risk zone mapping. The core of the response was an efficient cycle of “detection–reporting–response,” which reflects the operational strength of China's grassroots public health system. The Foshan model offers a scalable and replicable approach for other regions facing similar vector-borne outbreaks. Direct detection confirms active infection by identifying viral components. Main methods include: Reverse transcription PCR/quantitative reverse transcription PCR was used to test viral RNA. This is the gold standard for early diagnosis. Viral RNA can be detected during the viremic phase (1–7 days post-onset), with the highest detection rate within the first 1–3 days. Serum is preferred, although nasopharyngeal swabs, whole blood, saliva, and urine may also be used 6, 7. High sensitivity and specificity; rapid results (4–6 h); differentiates CHIKV from similar viruses (e.g., dengue, Zika). Sensitivity decreases after 7 days post-onset; requires advanced laboratory infrastructure and trained personnel. This method enabled the “same-day reporting and disposal” model used during the Foshan outbreak, supporting outbreak tracing and timely isolation. This detects viral proteins (e.g., E1, E2, NS1) using rapid diagnostic tests such as immunochromatographic strips (e.g., colloidal gold, latex-based). Serum collected within 1–5 days of symptom onset is ideal 8. The use of rapid antigen testing in community settings offers advantages like speed and accessibility, but it also faces distinct challenges, particularly in resource-limited or pathogen-coendemic regions. Rapid (15–30 min); cost-effective; suitable for decentralized settings; valuable for early-stage screening where PCR is unavailable. Lower sensitivity than PCR; cross-reactivity with other alphaviruses can lead to false positives in pathogen-co-endemic regions; rapid antigen testing performance is highly dependent on viral load; only provides qualitative results. This method was usually used at early outbreak response, community screening where PCR infrastructure is lacking, and triage of suspected cases for further PCR confirmation. Virus culture involves inoculating clinical samples into cell lines (e.g., Vero, C6/36) and observing cytopathic effects or using immunofluorescence techniques 9. Produces live virus strains for genomic analysis, typing and traceability analysis; foundation for vaccine development and drug screening; facilitation of viral mutation and evolution research. Time-consuming and technically demanding; requires biosafety level 2 or higher facilities. This method is primarily used in fundamental basic virology research and epidemiological surveillance rather than routine diagnostics. Serological testing detects host antibodies (IgM, IgG) generated in response to CHIKV infection 10: IgM appears around 5–7 days post-infection and can persist for 3–6 months. IgG appears after ∼2 weeks and may persist for years. Commonly used methods include: (1) Enzyme linked immunosorbent assay: High throughput and sensitive; ideal for centralized labs. (2) Neutralization Test: Highest specificity; used for confirmation due to potential cross-reactivity with dengue and Zika viruses. (3) Colloidal Gold Method: Simple, rapid, suitable for field settings but lower sensitivity. Given the antigenic similarities between CHIKV and other arboviruses, confirmation with PCR or neutralization testing is often necessary. Diagnostic method selection should be guided by the stage of infection: (1) < 7 days post-onset: Reverse transcription PCR is preferred due to high viremia. (2) ≥ 7 days: IgM testing is appropriate; confirmation can be done via IgG seroconversion or rising titers. (3) Retrospective diagnosis or seroprevalence assessment: IgG serology is most useful. A single test result must be interpreted alongside clinical symptoms (e.g., fever, rash, arthralgia) and epidemiological history (e.g., travel to endemic areas, mosquito exposure). Paired acute and convalescent serum samples (collected 2–4 weeks apart) improve diagnostic accuracy 11. Accurate diagnosis of CHIKF requires a stage-specific testing strategy supported by clinical and epidemiological evidence. The Foshan outbreak demonstrated the value of integrated surveillance systems, rapid diagnostics, and timely intervention. These practices offer a model for managing emerging arboviruses globally. CHIKF continues to re-emerge in tropical and temperate zones—including Europe 12. Since the first outbreak of chikungunya in Italy in 2007, Europe has been facing an increase in local transmission of arboviral diseases. The global mobility of vectors and travelers underscores the need for coordinated international surveillance systems. International cooperation, data sharing, and joint research are crucial to confronting the growing threat of vector-borne diseases in an era of global mobility and climate change 13. Yingli Li: writing original draft preparation (equal). Yi-Wei Tang: review & editing (lead). The authors have nothing to report. The authors have nothing to report. The authors have nothing to report. Professor Yi-Wei Tang is the Co-Editor-in-Chief of iLABMED Editorial Board. To minimize bias, he was excluded from all editorial decision-making related to the acceptance of this article for publication. The remaining author declares no conflict of interest. Data derived from public domain resources.
Li et al. (Mon,) studied this question.