Overview: Brucellosis in Henan Province over six decades
Brucellosis, a zoonotic disease caused by Brucella species, continues to pose a public health and economic threat in China and beyond. In Henan Province, located in central China, the disease has a long history of endemic transmission. This article syntheses the spatiotemporal epidemiology of human brucellosis in Henan from 1956 through 2023, highlighting periods of rise, geographic spread, and implications for control strategies.
Long-term trends and epidemic phases
The Henan data reveal two major epidemic phases. The first, from 1956 to 1980, saw a high incidence with an average annual rate of about 1.46 per 100,000 and a peak in 1969 when incidence reached 11.79 per 100,000. A comprehensive control program, including animal vaccination and improved sanitation, suppressed transmission by 1980. However, brucellosis re-emerged after 2000, coinciding with rapid growth in the livestock sector. From 2000 to 2023, the province experienced a renewed upward trajectory, with an average annual incidence around 2.2 per 100,000 and an average of over 2,100 reported cases annually. This shift underscores how changes in animal husbandry and trade can reintroduce risk even in areas with a history of control.
Geographic spread: from northwest to east
Spatial analyses show a gradual expansion from northwest Henan, near Shaanxi and Shanxi, toward central and eastern regions. By 2004, high-incidence counties clustered in the province’s northwest, while by 2023 the disease had disseminated to 18 cities and most counties. The count of affected counties rose from 39 (in 2004) to at least 155 (in 2023), with incidence increasing from 0.10 to 5.21 per 100,000 over the study period. The pattern aligns with broader regional dynamics in northern China, where brucellosis has spread from pasture and livestock-intensive areas into agricultural zones and peri-urban settings.
County- and city-level dynamics: focal clusters
Joinpoint and space–time analyses reveal substantial heterogeneity. At the county level, northwest Henan bore the earliest and strongest signals of transmission, while eastern areas showed rising trends in later years. City-level trends varied: Pingdingshan and Nanyang reported higher case counts, with others showing rapid growth rates in certain periods. The overall message is clear—while some western counties acted as persistent hubs, the disease gradually permeated central and eastern parts of the province, reflecting both animal movement and evolving human–animal contact patterns.
Spatiotemporal clusters: high-risk and low-risk areas
Retrospective space–time scanning identified two notable clusters from 2004 to 2023. A primary high–high cluster included 31 counties in western Henan (Nanyang, Luoyang, Pingdingshan, Sanmenxia, Zhumadian) with elevated risk during 2014–2023 (relative risk ≈ 5.37). Conversely, a large low–low cluster encompassed 81 eastern counties (Shangqiu, Kaifeng, Zhoukou, Xinxiang, Puyang, Xuchang, Xinyang, and others) from 2010 to 2019, indicating substantial regional disparities in transmission. The spatial pattern suggests an expansion risk toward eastern Henan, reinforcing the need for cross-district coordination and consistent surveillance across the province.
Implications for control and policy
The Henan study emphasizes that control of human brucellosis must harmonize animal and human health strategies. Key measures include targeted vaccination of livestock in high-risk areas, regulated animal movement to prevent spread from high- to low-incidence zones, and enhanced veterinary and food-safety practices. The observed eastward expansion highlights the necessity of regional collaboration with neighboring provinces such as Shaanxi, Shanxi, Anhui, and Hubei to address cross-border transmission risks.
Limitations and future directions
Limit include potential underreporting in earlier decades and evolving diagnostic criteria over time. Improved, standardized prospective surveillance and molecular characterization of Brucella strains would deepen understanding of transmission pathways and help tailor interventions to local ecological contexts.
Conclusion
The spatiotemporal evolution of human brucellosis in Henan Province from 1956 to 2023 shows an initial strong control success followed by a re-emergence and geographic spread driven by livestock development and animal movement. Persistent high-risk pockets in the northwest and emerging risks in the east call for sustained, integrated One Health interventions to curb transmission and protect both human health and animal productivity.
