Epidemic characteristics and transmission risk prediction of brucellosis in Xi'an city, Northwest China

Abstract

Human brucellosis (HB) has re-emerged in China since the mid-1990s, and exhibited an apparent geographic expansion shifted from the traditional livestock regions to the inland areas of China. It is often neglected in non-traditional epidemic areas, posing a serious threat to public health in big cities. We carried out a retrospective epidemiological study in Xi'an, the largest city in northwestern China. It utilizes long-term surveillance data on HB during 2008–2021 and investigation data during 2014–2021. A total of 1989 HB cases were reported in Xi'an, consisting of 505 local cases, i.e., those located in Xi'an and 1,484 non-local cases, i.e., those located in other cities. Significantly epidemiological heterogeneity was observed between them, mainly owing to differences in the gender, occupation, diagnostic delays, and reporting institutions. Serological investigations suggested that 59 people and 1,822 animals (sheep, cattle, and cows) tested positive for brucellosis from 2014 to 2021, with the annual average seroprevalence rates were 1.38 and 1.54%, respectively. The annual animal seroprevalence rate was positively correlated with the annual incidence of non-local HB cases. Multivariate boosted regression tree models revealed that gross domestic product, population density, length of township roads, number of farms, and nighttime lights substantially contributed to the spatial distribution of local HB. Approximately 7.84 million people inhabited the potential infection risk zones in Xi'an. Our study highlights the reemergence of HB in non-epidemic areas and provides a baseline for large and medium-sized cities to identify regions, where prevention and control efforts should be prioritized in the future.

Socioeconomic, meteorological factors and spatiotemporal distribution of human brucellosis in China between 2004 and 2019—A study based on spatial panel model

“…Therefore, it is significant to enhance the quarantine of livestock, strengthen the controls on livestock products to prevent contaminated products from entering the market [39] and strengthen the sterilization of animal products in food processing. Human brucellosis incidence was positively correlated with gross pastoral product in the middle reaches of the Yangtze River, which was consistent with the findings of Zhao et al [40]. The improvement of residential standards has accelerated the development of animal husbandry and the processing and transportation of livestock products, increasing the exposure of animal hosts [39].…”

The spatiotemporal epidemiological study on human brucellosis in shenyang, China from 2013 to 2022

“…In this study, the average level of annual incidence of HB was observed to be 5.52 per 100,000 individuals in Shenyang, Liaoning Province, which was higher than that in China [ [16] , [17] , [18] , [19] , [20] ] and in Xian, Shanxi Province [ 35 ], but lower than that in Shanxi Province [ 36 , 37 ], the Inner Mongolia Autonomous Region [ 38 , 39 ], and Liaoning Province [ 24 , 25 ]. Shenyang, the capital city of Liaoning Province and Xian, the capital city of Shanxi Province, exhibit a higher degree of urbanization compared to other cities in their respective provinces.…”

The spatiotemporal trend of human brucellosis in China and driving factors using interpretability analysis

“…Increased GDP can lead to higher investment in infrastructure, which is instrumental in improving the living standards of residents and enhancing the accessibility of medical resources. On the other hand, as the standard of living in China has improved, there has been an increased demand for animal protein, leading to a rise in livestock production, slaughter, and transportation for meat consumption 22 . Consequently, more individuals contact animal hosts and their vectors, potentially increasing the risk of disease transmission to humans 35 .…”

“…Furthermore, the increase in residents’ education funds has led to improvements in education levels and heightened disease awareness. As individuals become more educated, they are more likely to be aware of diseases and take necessary precautions 22 . Increased investment in education can enable a wider range of individuals to acquire an education, leading to a higher level of health and disease awareness among the population.…”

“…China has a wide variety of ecological, environmental, meteorological, and economic landscapes throughout the country. The epidemiological characteristics and causes of human brucellosis vary, especially as the area has significantly different landscapes 16 – 22 . Previous studies have focused on the incidence of human brucellosis in mainland China, which has been instructive and illuminating for the prevention and control of human brucellosis 20 , 23 , 24 .…”