Vital Surveillances: Notified Vector-Borne Diseases — China, 2005–2024

This study analyzed data from 14 VBDs recorded in the China national infectious disease surveillance system from 2005 to 2024. We categorized these diseases into four groups: mosquito-borne diseases (dengue, malaria, Japanese encephalitis, Zika virus disease, and filariasis), tick-borne diseases [severe fever with thrombocytopenia syndrome (SFTS) and tick-borne encephalitis], rodent-borne diseases [hemorrhagic fever with renal syndrome (HFRS), leptospirosis, and plague], and others (scrub typhus, schistosomiasis, typhus group rickettsiosis, and leishmaniasis). After excluding 32,102 suspected cases, we analyzed the spatial distribution, temporal trends, and demographic characteristics of these four VBD categories over the 20-year period. We used analysis of variance to examine differences in continuous variables between groups, Chi-square tests to analyze differences in categorical variables, and the Mann-Kendall trend test to evaluate temporal trends in disease incidence. All data processing and statistical analyses were performed using R (version 4.2.2; The R Foundation for Statistical Computing, Vienna, Austria).

From 2005 to 2024, China reported a total of 1,129,736 cases of VBDs (annual incidence rate of 4.13 per 100,000), with 6,096 deaths (Table 1). Scrub typhus accounted for the highest number of cases (318,258), followed by malaria (235,033), HFRS (207,850), and dengue (142,422). Tick-borne diseases exhibited the highest cumulative fatality rate (4.33%) during this period. Among individual diseases, plague had the highest case fatality rate (38.33%), followed by Japanese encephalitis (4.9%) and SFTS (4.79%). The mean age of all VBD cases was 43.85 years (SD: 20.04), with tick-borne disease cases having the highest mean age of 61.51 years (SD: 13.66). Males comprised a higher proportion of cases in all disease categories except tick-borne diseases. Across all VBD types, farmers represented a significantly higher proportion of cases compared to individuals in other occupations (Table 2, all P<0.05).

Mosquito-borne diseases, primarily malaria (56.39%) and dengue (34.17%), are predominantly distributed in the southern regions of China (Figure 1). Tick-borne diseases, mainly SFTS (89.07%), are concentrated in Central and Eastern China. Rodent-borne diseases, predominantly HFRS (95.53%), are primarily found in Northeast China and along the middle and lower reaches of the Yangtze and Yellow Rivers. Other vector-borne diseases, chiefly scrub typhus (69.63%), are mainly distributed across Southwest and South China regions. Notably, dengue, scrub typhus, and SFTS have demonstrated annual increases in geographic spread, with reported cases expanding to 10.89, 12.37, and 7.07 more cities each year, respectively (Supplementary Figures S1–S3).

Figure 1. 

Spatial distribution of VBDs in China from 2005 to 2024. (A) VBDs; (B) Mosquito-borne diseases; (C) Tick-borne diseases; (D) Rodent-borne disease; (E) Other diseases.

Abbreviation: VBD=vector-borne disease; No.=number.

Map approval number: GS京(2025)0996号.

From 2005 to 2024, the incidence of VBDs in China has exhibited a fluctuating pattern with three distinct peaks occurring in 2006, 2014, and 2024 (P=0.721, Figures 2A and 2C). Mosquito-borne and rodent-borne diseases showed significant declining trends, while tick-borne diseases and other VBDs demonstrated significant increasing trends (all P<0.05). The first two peaks were primarily attributed to outbreaks of malaria and dengue, while the 2024 peak resulted mainly from increased scrub typhus and dengue cases. From 2004 to 2014, malaria and HFRS cases constituted a higher proportion of VBDs in China, whereas from 2014 to 2024, dengue, SFTS, and scrub typhus became more prevalent. Mann-Kendall trend analysis revealed that rodent-borne diseases (HFRS, leptospirosis), malaria, Japanese encephalitis, schistosomiasis, and typhus group rickettsiosis have shown significant declining trends, while SFTS, dengue, and scrub typhus have demonstrated significant increasing trends (all P<0.05). Additionally, VBDs exhibit distinct seasonal distribution patterns (Figure 2B and 2D). HFRS displays bimodal annual incidence peaks, dengue cases peak from June to October, and SFTS cases peak from May to August. Scrub typhus shows a higher proportion of cases from June to November.

Figure 2. 

The trends in incidence and seasonal characteristics of VBDs in Mainland China from 2005 to 2024. (A) Annual case distribution (%) of vector-borne diseases by disease; (B) Monthly case distribution (%) of vector-borne diseases by disease; (C) Annual reported cases of VBDs by vector category; (D) Monthly reported cases of vector-borne diseases by vector category.

Abbreviation: VBD=vector-borne disease; No.=number; HFRS=hemorrhagic fever with renal syndrome; SFTS=severe fever with thrombocytopenia syndrome.

From 2005 to 2024, VBDs in China exhibited a fluctuating trend, with previous studies documenting a fluctuating decline from 2005 to 2020 (1), followed by a notable increase in recent years. This recent upward trend necessitates strengthened preventive measures to mitigate further case increases in 2025. Over the past two decades, high-threat diseases such as plague, HFRS, malaria, and Japanese encephalitis have been generally controlled. However, dengue has emerged as a significant mosquito-borne disease, replacing malaria and Japanese encephalitis as a major public health threat in China. Additionally, SFTS, a newly emerging tick-borne disease, presents a high fatality rate that warrants urgent attention. While rodent-borne diseases have generally been controlled, HFRS cases remain at concerning levels. Therefore, China should intensify measures to prevent the spread of dengue and SFTS, while also focusing on the prevention of key VBDs and emerging infectious diseases to avoid outbreaks.

In the context of global warming and urbanization, preventing mosquito-borne disease outbreaks and controlling their northward spread should be prioritized (7). SFTS, as an emerging infectious disease, is spreading rapidly, necessitating enhanced research and prevention efforts to identify factors driving its spread and prevent further expansion (8). Scrub typhus, which has become a major VBD in recent years in China, is primarily prevalent in southern regions and manifests a trend of further geographical expansion (9). Simultaneously, flea monitoring should be strengthened to prevent potential plague outbreaks in endemic areas. In high-risk regions, vaccination efforts should be intensified to prevent HFRS outbreaks, with particular attention to outbreaks triggered by extreme events such as floods (10). Additionally, prevention and control measures for dengue and scrub typhus should be strengthened before summer and autumn, while HFRS prevention should be enhanced before winter and spring. Currently, the epidemiological trends of VBDs in China pose a significant health threat to the population, especially among elderly farmers who are particularly vulnerable due to their poor health status and low economic resources. Tailored interventions should be developed, including community health education, free vaccination programs, and early warning systems to reduce social inequities.

In summary, a substantial gap remains between China’s current VBD control efforts and the goals proposed by the World Health Organization. Therefore, intensified efforts are needed to prevent the continued increase in VBD cases in and beyond 2025, especially for the control and prevention of dengue, scrub typhus, and SFTS. Additionally, we need to strengthen monitoring and prevention of outbreaks of emerging infectious diseases and those not legally required to be reported. We should also promote patriotic health campaigns, implement integrated vector management, and ensure sustainable vector control to effectively mitigate VBD risks (11). This study has several limitations. First, some VBDs, such as Yellow Fever, Lyme disease, and bartonellosis, were not included in the disease notification system and therefore were not analyzed. Second, there may be cases where individuals did not seek medical treatment and thus were not reported, potentially resulting in a higher actual disease burden than reflected in this study. Finally, the 20-year epidemic trend of VBDs may have been influenced by monitoring capabilities, the COVID-19 pandemic, and various natural social policy events.

The Chinese Center for Disease Control and Prevention for their software support and administrative assistance.