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Transboundary and emerging diseases2026; 2026(1); e6061208; doi: 10.1155/tbed/6061208

Surveillance on African Horse Sickness Virus in China’s Southern Border Regions.

Abstract: African horse sickness (AHS) is a vector-borne and noncontagious disease caused by African horse sickness virus (AHSV) that poses a severe threat to the global equine industry. As a country historically free from AHS, China faces elevated risks due to recent outbreaks in Southeast Asia in 2020 and its ecological suitability of its border regions for AHSV vectors. Therefore, we conducted consecutive molecular and serological surveillance for AHSV in high-risk border regions from 2020 to 2024. A total of 3203 equine serum samples, 2909 whole-blood samples, and 1037 collections of blood-sucking insects were collected from 103 counties across five border provinces from June to October (peak Culicoides season). Samples were analyzed using World Organization for Animal Health (WOAH)-recommended RT-qPCR (targeting VP7 gene) and blocking ELISA. Morphological identification confirmed that the collected vectors were primarily Culicoides midges, with some mosquitoes. No AHSV nucleic acid or specific antibodies were detected, which is consistent with China's AHS-free status. Combined with predictive models and regional risk factors, the likelihood of AHSV occurrence in southern China is "likely." The study highlights the urgent need for continuous surveillance and risk assessment to safeguard China's equine industry. Further regional and ecological studies on vectors and animal transportation are also essential for understanding and mitigating the risks associated with AHSV introduction.
Copyright © 2026 Feng Zhang et al. Transboundary and Emerging Diseases published by John Wiley & Sons Ltd.
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Publication Date: 2026-07-09 PubMed ID: 42421464PubMed Central: PMC13346924DOI: 10.1155/tbed/6061208Google Scholar: Lookup
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Summary

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Overview

  • This study conducted extensive surveillance for African horse sickness virus (AHSV) in southern border regions of China from 2020 to 2024.
  • Despite no detection of AHSV in samples, the research emphasizes the ongoing risk of virus introduction and the importance of continuous monitoring to protect the equine industry.

Background and Significance

  • African horse sickness (AHS) is a serious, noncontagious viral disease affecting horses and related equids, transmitted primarily by Culicoides biting midges.
  • The disease is caused by African horse sickness virus (AHSV), which threatens global equine health and the horse industry due to high fatality rates in horses and limitations on horse movement in affected areas.
  • Historically, China has been free of AHS, offering a protective environment for its equine industry.
  • However, recent outbreaks in Southeast Asia in 2020 have raised concerns about potential spread, especially since southern Chinese border regions have ecological conditions conducive to the Culicoides vectors that transmit AHSV.

Study Objectives and Approach

  • The main goal was to monitor the presence of AHSV in high-risk border areas through molecular and serological surveillance.
  • Sampling targeted five southern border provinces considered high risk due to proximity to AHS outbreaks and suitable vector habitats.
  • Sampling was conducted during June to October, the peak season for Culicoides midge activity, enhancing the likelihood of virus detection if present.

Sample Collection and Testing

  • Samples collected included:
    • 3203 equine serum samples (to detect antibodies indicating past exposure to AHSV)
    • 2909 equine whole blood samples (for detecting viral RNA)
    • 1037 collections of hematophagous (blood-sucking) insects, primarily Culicoides midges and some mosquitoes, which are potential virus vectors
  • Samples were taken from 103 counties across five provinces, representing broad geographic coverage of border areas.
  • Laboratory testing involved:
    • RT-qPCR targeting the VP7 gene of AHSV, a highly conserved region used to detect viral genetic material.
    • Blocking ELISA tests to detect antibodies specifically against AHSV, indicating exposure or infection history in horses.
  • Morphological identification techniques confirmed the species of collected insects, verifying the presence of main vector species, Culicoides midges.

Key Findings

  • No AHSV nucleic acid was detected in blood or insect samples by RT-qPCR, indicating no active viral infections in the tested equine populations or vectors.
  • No antibodies against AHSV were found in serum samples, suggesting no prior exposure among the tested horses during the surveillance period.
  • Findings support the current official status of China as free from AHS.

Risk Assessment and Implications

  • Despite negative test results, predictive models incorporating ecological factors, vector presence, and recent outbreak data classify the likelihood of AHSV introduction into southern China as “likely.”
  • Factors contributing to risk include:
    • Proximity to Southeast Asian countries with recent outbreaks
    • Suitable climate and habitats for Culicoides vectors
    • Animal transportation and trade that could inadvertently introduce infected horses or vectors
  • The study highlights the necessity for:
    • Ongoing, periodic surveillance to rapidly detect any incursion of AHSV
    • Risk assessments to inform biosecurity and prevention strategies
    • Further research on vector ecology to understand seasonality, distribution, and control options
    • Enhanced monitoring of animal movement across borders to prevent introduction

Conclusion

  • This comprehensive surveillance confirms the absence of African horse sickness virus in China’s southern border regions as of 2024.
  • However, due to ecological vulnerability and regional virus activity, AHSV introduction remains a significant threat requiring vigilant monitoring.
  • Proactive surveillance, research, and control measures are critical to safeguarding the health of equine populations and the related industries in China.

Cite This Article

APA
Zhang F, Wang S, Xu T, Ren W, Zou Y, Ren Y, Zhao Y, Fang L, Liu S, Zeng B, Zheng M, Qin J, Zhao H, Zhou Q, Wu J, Nuermaimaiti A, Chen R, Wang N, Li J, Zhang Z, Wang Z, Bao J. (2026). Surveillance on African Horse Sickness Virus in China’s Southern Border Regions. Transbound Emerg Dis, 2026(1), e6061208. https://doi.org/10.1155/tbed/6061208

Publication

Transboundary and emerging diseases
ISSN: 1865-1682
NlmUniqueID: 101319538
Country: Germany
Language: English
Volume: 2026
Issue: 1
Pages: e6061208
PII: 6061208

Researcher Affiliations

Zhang, Feng
  • Exotic Herbivore Disease Surveillance and Research Center, China Animal Health and Epidemiology Center, Qingdao, Shandong, China.
  • Key Laboratory of Animal Biosafety Risk Prevention and Control(South), Ministry of Agriculture and Rural Affairs, Qingdao, Shandong, China, agri.gov.cn.
Wang, Shujuan
  • Exotic Herbivore Disease Surveillance and Research Center, China Animal Health and Epidemiology Center, Qingdao, Shandong, China.
  • Key Laboratory of Animal Biosafety Risk Prevention and Control(South), Ministry of Agriculture and Rural Affairs, Qingdao, Shandong, China, agri.gov.cn.
Xu, Tiangang
  • Animal Health Assessment Division, China Animal Health and Epidemiology Center, Qingdao, Shandong, China.
Ren, Weijie
  • Exotic Swine Disease Surveillance and Research Center, China Animal Health and Epidemiology Center, Qingdao, Shandong, China.
Zou, Yanli
  • Exotic Swine Disease Surveillance and Research Center, China Animal Health and Epidemiology Center, Qingdao, Shandong, China.
Ren, Yingchao
  • Animal Health Assessment Division, China Animal Health and Epidemiology Center, Qingdao, Shandong, China.
Zhao, Yonggang
  • Exotic Herbivore Disease Surveillance and Research Center, China Animal Health and Epidemiology Center, Qingdao, Shandong, China.
Fang, Linlin
  • Exotic Herbivore Disease Surveillance and Research Center, China Animal Health and Epidemiology Center, Qingdao, Shandong, China.
Liu, Shuang
  • Exotic Herbivore Disease Surveillance and Research Center, China Animal Health and Epidemiology Center, Qingdao, Shandong, China.
Zeng, Bangquan
  • Yunnan Center for Animal Disease Control and Prevention, Kunming, Yunnan, China.
Zheng, Min
  • Guangxi Zhuang Autonomous Region Center for Animal Disease Control and Prevention, Nanning, Guangxi Zhuang Autonomous Region, China.
Qin, Ju
  • Xinjiang Uygur Autonomous Region Center for Animal Disease Control and Prevention, Urumqi, Xinjiang Uygur Autonomous Region, China.
Zhao, Huanyun
  • Yunnan Center for Animal Disease Control and Prevention, Kunming, Yunnan, China.
Zhou, Qingan
  • Guangxi Zhuang Autonomous Region Center for Animal Disease Control and Prevention, Nanning, Guangxi Zhuang Autonomous Region, China.
Wu, Jianhao
  • Guangxi Zhuang Autonomous Region Center for Animal Disease Control and Prevention, Nanning, Guangxi Zhuang Autonomous Region, China.
Nuermaimaiti, Amuti
  • Xinjiang Uygur Autonomous Region Center for Animal Disease Control and Prevention, Urumqi, Xinjiang Uygur Autonomous Region, China.
Chen, Ronggui
  • Yili Kazakh Autonomous Prefecture Center for Animal Disease Control and Prevention, Yili Kazakh Autonomous Prefecture, Xinjiang Uygur Autonomous Region, China.
Wang, Nan
  • Yili Kazakh Autonomous Prefecture Center for Animal Disease Control and Prevention, Yili Kazakh Autonomous Prefecture, Xinjiang Uygur Autonomous Region, China.
Li, Jinming
  • Exotic Swine Disease Surveillance and Research Center, China Animal Health and Epidemiology Center, Qingdao, Shandong, China.
Zhang, Zhicheng
  • Exotic Herbivore Disease Surveillance and Research Center, China Animal Health and Epidemiology Center, Qingdao, Shandong, China.
Wang, Zhiliang
  • Exotic Herbivore Disease Surveillance and Research Center, China Animal Health and Epidemiology Center, Qingdao, Shandong, China.
Bao, Jingyue
  • Exotic Herbivore Disease Surveillance and Research Center, China Animal Health and Epidemiology Center, Qingdao, Shandong, China.

MeSH Terms

  • Animals
  • African Horse Sickness / epidemiology
  • African Horse Sickness / virology
  • African Horse Sickness Virus / isolation & purification
  • China / epidemiology
  • Horses
  • Ceratopogonidae / virology
  • Insect Vectors / virology

Grant Funding

  • 2022YFD1800500 / National Key Research and Development Program of China

Conflict of Interest Statement

The authors declare no conflicts of interest.

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