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The continuous expansion and spread of human brucellosis in the Xinjiang Uygur Autonomous Region: evidence from epidemiological and strains’ genotyping-based analysis

BMC Microbiology volume 25, Article number: 181 (2025) Cite this article

Abstract

Human brucellosis is a severe public health threat in Xinjiang; however, the epidemiological evolution and molecular correlation of strains are still unclear. In this study, join point regression analysis, spatiotemporal scan analysis, conventional biotyping approaches, and multiple locus variable-number tandem repeat analysis (MLVA) were applied to characterize the epidemiological landscape. A total of 78,689 cases were reported from 1957 to 2023. The average annual reported cases and incidence rates were 1174.46 and 5.28/100,000, respectively. Join point analysis revealed that disease incidence trends increased from 2004 (329, 1.77/100,000) to 2023 (9,334, 36.08/100,000) (AAPC = 17.26, P = 0.00), and affected counties expanded from 21 in 2004 to 100 in 2023, implying that human brucellosis continues to worsen. In 2023, the incidence rates in most counties in southern Xinjiang were higher than 2.0/100,000, and human brucellosis has become endemic in southern Xinjiang. These data demonstrate that human brucellosis is continuously spreading and expanding in Xinjiang. High incidence rate of clusters was detected in North Xinjiang from 2013 to 2023, involving 54 counties. The substantial increase in ruminant farming has increased the risk of infection in humans. A total of 28 Brucella strains were isolated in patients, all B. melitensis bv. 3. MLVA revealed that the dominant genotypes consisted of strains from different areas, hosts, and years; strains from a common original continuously spread, small ruminant trade and transfer contributed to the spread of strains in adjacent regions. Therefore, strengthening surveillance and control of animal brucellosis is vital for preventing its further spread.

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Introduction

Brucellosis is a zoonosis reported for the first time in 1859 by Marston in Malta, and its causative agent was first isolated from the spleen of deceased soldiers by David Bruce in 1886 [1]. Brucellosis has continued to cause significant medical and veterinary problems because it has long been underestimated and neglected [2]. An evidence-based conservative estimate of the annual global incidence is 2.1 million, significantly higher than was previously assumed [3]. Human brucellosis poses significant diagnostic challenges due to multisystem involvement and unusual clinical presentations, and it can also cause considerable economic losses in the animal farming industry [4]. In China, the average direct economic loss of each infected sheep was 4 557 yuan (excluding dairy sheep) in 2020, and the loss in each province was from 0.18 to 2.04 billion yuan [5].

Brucella strains invade the body through the skin mucosa, digestive tract, and respiratory tract; direct/indirect contact with infected animals and the consumption of raw meat and dairy products are the main infection routes in humans [6, 7]. The epidemiology of human brucellosis has drastically changed in the last few decades because of various sanitary situations, socioeconomic and political factors, and the evolution of international travel [8]. In China, brucellosis was first recorded in two foreigners in Shanghai in 1905, after which sporadic suspected cases were reported [9]. However, formal surveillance was started in 1950. Over the past seven decades, cases have been reported in all 31 mainland provinces in China, and affected areas have expanded from northern pastureland regions to southern coastal areas [10, 11].

The Xinjiang Uygur Autonomous Region (Xinjiang) is located in northwestern China; human brucellosis is historically endemic in this region because ruminant farming is a pillar industry [12]. Furthermore, Xinjiang borders Mongolia, Kazakhstan, and Kyrgyzstan, and animal and human brucellosis is endemic, with a high incidence rate in these countries [13,14,15]. One survey revealed that although the incidence rate of human brucellosis in Xinjiang has decreased from 35.6/100,000 in 2016 to 16.3/100,000 in 2019 [16], investigations into the epidemiological evolution of human brucellosis and the molecular correlation of strains from different hosts and areas remain lacking. Therefore, this study aimed to investigate the epidemiological evolution of human brucellosis and the molecular relationships among strains, which will contribute to a better understanding of the epidemiological landscape, and tailor the surveillance and control measures.

Methods

Data sourcing, cleaning, processing, analysis, and visualization

Data on the reported cases and incidence rates of human brucellosis in Xinjiang from 2004 to 2023 were extracted from the National Information System for Disease Control and Prevention. The reported cases and incidence rates were used to illustrate the epidemic characteristics of human brucellosis. Owing to systematic case surveillance of human brucellosis that started in 2004 and two incidence peaks in 2015 and 2023, these 3 years were selected to depict the geographic change characteristics of human brucellosis. ArcGIS 10.7 software (Esri, Redlands, CA, USA) was used to visualize the geographic distribution of human brucellosis at the county scale.

Join point regression analysis of human brucellosis from 2004 to 2023

Join point regression analysis of human brucellosis from 2004 to 2023 was conducted as previously described [17]. Briefly, the annual percentage change (APC) and the average annual percentage change (AAPC) for each segment were estimated using join point regression, focusing on estimating the temporal trends in the incidence rate of human brucellosis. P < 0.05 was considered to indicate significance. To ensure that the results were credible, a maximum of four points were set: the Join-point Regression program Version 5.3.0 (Information Management Services Inc., Calverton, MD, USA) from the Statistical Research and Applications Branch of the Surveillance Research Program of the U.S. National Cancer Institute.

Retrospective space‒time analysis scanning analysis

For retrospective space–time analysis scanning for clusters with high or low rates via the discrete Poisson model by SaTScan v10.1.3 and QGIS 3.22.14, the parameter sets of the analysis software were set as previously described [18]. The maximum temporal scanning radius was 90 days, and the number of Monte Carlo simulations was 999. The log likelihood ratio (LLR) of the test statistics was constructed using actual and theoretical cases inside and outside the scanning window. The corresponding scanning window was the aggregation area when the LLR was significant (p < 0.05).

Isolation, identification, and DNA preparation of strains

The Brucella strains were isolated and identified using standard bacteriology procedures [19]. Briefly, 5–10 mL human blood samples from suspected brucellosis patients were injected into biphasic medium, and clean sheep organs (liver and spleen) were homogenized with PBS, coated with Brucella selective medium at 37 °C, and incubated for at least 2 weeks. The suspect colony was further subjected to conventional biototyping approaches, including CO2 requirements for growth, H2S production, growth in the presence of basic fuchsin and thionine, phage lysis, and agglutination with anti-A, -M monospecific sera [19]. All suspected strains were identified in the biosecurity level 3 laboratory. Before DNA extraction, the 28 strains were heat-inactivated at 80 °C for 10 min, and the QIAamp Genomic DNA Kit (Qiagen, Heidelberg, Germany) was used to prepare the genomic DNA of the strains according to the manufacturer’s protocol.

MLST and MLVA genotyping of strains

MLST genotyping of the 28 strains was performed as previously described [20]. Briefly, nine loci, including aroA, glk, dnaK, gyrB, trpE, cobQ, omp25, and int-hyp, were selected for MLST genotyping. PCR amplification of nine loci was performed in a 40 µL system, PCR products were evaluated via 1.0% agarose gel electrophoresis, and the expected products were sequenced. The sequences obtained from the PCR products were aligned via MEGA 6.0 software according to published allele MLST sequences (https://pubmlst.org/brucella/). Finally, the combined characteristics of the nine loci were identified as sequence types (STs) using the MLST online database.

MLVA genotyping and data analysis of the strains were performed as previously described [21]. Briefly, 16 loci were sorted into three panels—panel 1 (MLVA-8), panel 2 A, and panel 2B—to combine panel 1 (MLVA-8) and panel 2 A as MLVA-11. PCR amplification of 16 primers was performed in a 20 µL system, and the PCR products were preliminarily evaluated via agarose gel electrophoresis. The products were sequenced via capillary electrophoresis on an ABI Prism 3130 automated fluorescent capillary DNA sequencer (Applied Biosystems), and the fragment sizes of each locus were further converted to repeat unit numbers via Gene Mapper software version 4.0 (Applied Biosystems). Moreover, 110 strains of B. melitensis from animals (sheep (n = 100), cattle (n = 6), and goats (n = 4)) (Table S1) isolated in Xinjiang were collected for comparison of genetic correlations according to the minimum spanning tree generated with Bionumerics 8.0 software (Applied Maths, St-Martens-Latem, Belgium).

Results

Overview of the epidemic of human brucellosis in Xinjiang from 1957 to 2023

Human brucellosis can be divided into three stages: the epidemic stage from 1957 to 1986, the low epidemic phase from 1987 to 2003, and the re-emerging epidemic stage from 2004 to 2023 (Fig. 1). The average cases (incidence (/100,000)) annually in the three stages were 140 (1.39/100,000), 30.59 (0.16/10,000), and 3,698 (15.46/10,000), respectively. In the first stage, the highest incidence was 4.1/100,000 (n = 531) in 1981; however, the highest incidence in the high epidemic period was 39.14/100,000 in 2015 (n = 8,997), which was almost 17 times higher than that in 1981. Another epidemic peak was observed in 2023 (9,334, 36.08/100,000). The incidence rate declined gradually from 2016 to 2019 and then significantly increased again from 2021 to 2023 (Fig. 1). These data suggest that human brucellosis became a severe public threat to populations after 2004.

Fig. 1
figure 1

Epidemic evolution of human brucellosis in Xinjiang from 1957 to 2023. Note: Curves were constructed with Excel 2021 software on the basis of the number of reported cases and incidence rate from 1957 to 2023

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Geographic distribution characteristics of human brucellosis from 2004 to 2023

In 2004, cases were reported in only 21 counties, with the highest incidence in Fuyun County (58.27/100,000), followed by Yanqi Hui Autonomous County (54.96/100,000) and Burjin County (51.79/100,000) (Fig. 2A). In 2011, cases were observed in 75 counties, including Dabancheng District (157.41/100,000), Burjin County (119.83/100,000), Emin County (78.02/100,000), and Heshuo County (75.8046/100,000), and the incidence rates in 22 counties were higher than 10.0/100,000. Cases were reported in at least 97 counties in 2015, and the incidence rate reached a historical peak: 396.75/100,000 in the autonomous county of Qapqal Xibe, 260.59/100,000 in the autonomous county of Hutubi, 250.42/100,000 in the autonomous county of Hoboksar in Mongolia, and 233.69/100,000 in Huocheng County (Fig. 2B). The incidence rate in 87 counties was higher than 2.0//100,000. The counties with high incidence rates expanded from North to South Xinjiang. In 2023, the county number of reported cases increased to 100. The incidence rate in 66 counties was higher than 30.0/100,000 (Fig. 2C), with the highest incidence recorded in Jeminay County (224.77/100,000), followed by Huocheng County (214.92/100,000), Wuqia Xian (205.21/100,000), and Mulei Kazakh Autonomous County (201.69/100,000), and the lowest incidence recorded in Kuitun city (1.32/100,000) (Fig. 2C). The incidence rates in most counties in South Xinjiang were higher than 2.0/100,000 (Fig. 2C). Thus, human brucellosis has become endemic in South Xinjiang. These data revealed that the affected counties expanded from North Xinjiang toward North Xinjiang (Fig. 2A–C), and most counties with the highest incidence rates were distributed in North Xinjiang.

Fig. 2
figure 2

Geographic expanding trend of the incidence of human brucellosis in Xinjiang in three different years: 2004 (A), 2015 (B), 2023 (C). Note: the number in brackets indicates the number of counties with incidence rates within this range

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Join point regression analysis of human brucellosis from 2004 to 2023

The join point regression analysis revealed that epidemic trends of human brucellosis in Xinjiang included four join points from 2004 to 2023, and a significant increasing trend was observed from 2006 to 2009 (APC = 19.20, P < 0.05), from 2009 to 2015 (APC = 64.17, P < 0.05), and from 2020 to 2023 (APC = 44.69, P < 0.05); in contrast, an apparent declining period occurred from 2004 to 2006 (APC = − 12.29, P < 0.05) and from 2015 to 2020 (APC = − 23.24, P < 0.05) (Fig. 3A). Generally, disease incidence in Xinjiang has increased annually from 2004 to 2023 (AAPC = 17.26, P < 0.05). There were three join points in Altay Prefecture (Fig. 3B), Aksu Prefecture (Fig. 3C), and Bayingolin Mongolian Autonomous Prefecture (Fig. 3C), followed by two join points in Kizilsu Kirgiz Autonomous Prefecture (Fig. 3C) and Tarbagatay Prefecture (Fig. 3B), with only one join point in Changji Hui Autonomous Prefecture, Hotan Prefecture, Karamay, Turpan city, Urumqi, and Ili Kazakh Autonomous Prefecture. The epidemic in these regions exhibited an alternating trend of growth and decline; a zero-join point was found in the remainder of the region, including Hami City and Kashgar Prefecture. In these two regions, the disease showed a continuous increasing trend from 2004 to 2023 (Table 1). Overall, the epidemic of disease in all regions showed a significant increasing trend, and the range of AAPC was from 6.46 in Bayingolin Mongolian Autonomous Prefecture to 81.89 in Kizilsu Kirgiz Autonomous Prefecture, P < 0.05 (Table 2). These data suggest that Brucella infection in animals is rampant and that the geographic expansion of human brucellosis has occurred along with the movement of infected animals; thus, a comprehensive control plan for animals is urgently needed.

Table 1 Joinpoint analysis of human brucellosis in different regions in Xinjiang Uygur Autonomous Region from 2004 to 2023
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Table 2 Epidemic trends of human brucellosis in different regions in Xinjiang Uygur Autonomous Region from 2004 to 2023
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Fig. 3
figure 3

Epidemic trends of human brucellosis in Xinjiang (A) in North Xinjiang (B), and South Xinjiang (C) from 2004 to 2023 based on join point regression analysis. Note: the incidence rate (100,000) and year from 2004 to 2023 were imported into the software for join point analysis

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Temporospatial cluster analysis of human brucellosis from 2004 to 2023

The spatial cluster analysis revealed that the high cluster of human brucellosis was concentrated mainly in North China and Xinjiang, which had 54 counties, with a radius of 463.17 km, a time frame from 1 January 2013 to 31 December 2023 (LLR: 26270.51, RR: 5.54, and P < 0.001) (Fig. 4). A low cluster detected from 2004 to 2011 involved 37 counties, with a scanning radius of 641.65 km, and the time frame in the low cluster ranged from 1 January 2004 to 31 December 2012 (LLR = 13668.45, RR = 0.040, P < 0.001) (Fig. 4). This temporal‒spatial distribution pattern of disease was consistent with the epidemic period of human brucellosis in Xinjiang.

Fig. 4
figure 4

Temporal‒spatial cluster analysis of human brucellosis cases from 2004 to 2023 in Xinjiang. Note: Retrospective space‒time analysis scanning for clusters with high or low rates via the discrete Poisson model

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Brucella strain distribution profile and genotype genotyping

A total of 28 Brucella strains were isolated in this study, four of which were from animal samples (two from the liver and two from the spleen) and 24 were from patients. Conventional bio-typing revealed that the 28 strains were B. melitensis bv.3 (11 strains were from 2015, and 17 strains were from 2016), and all 28 strains were from 15 different counties in North Xinjiang. MLST analysis revealed that all strains presented a single sequence type, ST8. According to the MLVA results, the genotype (GT) and MLVA-11 genotypes of all 28 B. melitensis strains, namely, the panel 1 42 genotype and the MLVA-11 116 genotype, were consistent. These data demonstrated that all B. melitensis strains belong to the eastern Mediterranean lineage. Genetic relationship analysis of 138 strains within Xinjiang revealed that the predominant circulating MLVA-16 genotypes were strains from different regions (Fig. 5A), hosts (Fig. 5B), and years of isolation (Fig. 5C). These data suggest that the strains that descended from a common origin continuously spread between humans and livestock, implying that part of the source of human infection in South Xinjiang originated in North Xinjiang.

Fig. 5
figure 5

Genetic correlation of 138 Brucella melitensis strains from different regions (A), hosts (B), and years of origin (C). Note: A minimum spanning tree of strains was constructed on the basis of the MLVA-16 data via Bionumerics 8.0 software

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Discussion

Human brucellosis represents a serious public health concern in Xinjiang. In the present survey, we combined join point regression analysis, spatiotemporal scan analysis, conventional bio-typing approaches, and MLVA to characterize the epidemiological landscape of human brucellosis in this area. Our analysis revealed that human brucellosis is a re-emerging disease in Xinjiang, and two high epidemic stages were recorded. First, from 1957 to 1986, massive numbers of small ruminant vaccinated and eliminated infected animals were affected by this epidemic, resulting in a low epidemic stage lasting approximately two decades. Second, during the re-emerging epidemic stage from 2004 to 2023, multiple socioeconomic factors potentially played a vital role in driving the significant increase in human brucellosis, including but not limited to developing the animal farming industry, unrestricted large animal transportation, inadequate animal disease quarantine and control, and increased surveillance in human populations [22]. Because the incidence rate of human brucellosis was low after 1986, surveillance of brucellosis in animals and humans was subsequently discontinued in most provinces (cities). Owing to long-term ignorance, the number of reported cases increased at the end of the 1990s [23]. Sporadic cases were subsequently reported from 1995 to 2003. Xinjiang’s annual incidence decreased from 35.6/100,000 in 2016 to 16.3/100,000 in 2019, an average annual decrease of 22.9% [16]. After this, human brucellosis cases returned, and the number of cases gradually increased, with infections in the affected areas continuing to increase. Xinjiang is a domestic livestock farming area, and the annual incidence of brucellosis in high-risk professional populations (farmers, herdsmen, and veterinarians) is approximately 6.4–7.6% [24]. A survey revealed that human brucellosis infections in Xinjiang were associated mainly with close contact with cattle and sheep [25]. In 2022, the highest incidence of brucellosis was reported in Wuqia Xian in southern Xinjiang, which borders Kyrgyzstan. In Kyrgyzstan, the prevalence of brucellosis in humans and animals is higher than in other Central Asian countries, estimates that 500–900 new cases of human brucellosis have been reported annually from 2012 to 2019 [26]. Persistent traditional agricultural practice and lifestyles, and consumption of raw dairy products, contribute to high prevalence [26]. Similar, brucellosis is a significant zoonotic infection of Pakistani ruminants, which was a pertaining to the region’s public health and livestock [27]. In India, the overall prevalence of anti-Brucella IgG antibodies was calculated at 16.65%, and the highest seropositivity was found in Sambalpur district (29.73%) and the lowest was determined in Mayurbhanj district [28]. Research has revealed that lower mean annual temperatures and increased beef, mutton, and milk production significantly correlate with high brucellosis incidence [29]. In addition, the natural environment, the production and lifestyle of the inhabitants, the number, distribution, and cross-regional movement of infectious livestock, and low self-protective awareness of farmers contribute to the increased risk of infection in human populations [30, 31]. Another study revealed that reducing the number of sheep/cattle births, increasing the slaughter rate of infected sheep/cattle, increasing the vaccination rate of susceptible sheep/cattle, and decreasing the vaccination loss rate are effective strategies for controlling brucellosis epidemics [32]. Due to inefficient surveillance and control programs contributing to the failure of brucellosis eradication in the Nile River Basin countries, including inappropriate disposal of aborted materials, insufficient government compensation for infected animals, and lack of cooperation between policymakers, health professionals, and stockholders [33].Therefore, implementing a strict control plan, including the restricted transfer of infected animals and the timely elimination of sick animals, and improving the self-protection of high-risk populations are priorities for further spread. Brucellosis epidemics are obvious in terms of seasonality and population features; the incidence peak occurs from May to August, and most cases involve farmers aged 30–50 years; the infection rate is significantly higher in males than in females [34, 35]. In Algeria, a survey revealed that 15% of veterinarians got infected with brucellosis during their practice, almost half (47%) contracted the disease through direct contact with diseased animals and/or their products, mostly during intervention for the retained placenta [36]. Health and veterinary departments should consider targeted intervention measures, including improving the hygiene of animal farms, strengthening disinfection measures in farming environments, and mandatory requirements for high-risk individuals to wear personal protective equipment during high-incidence seasons to reduce infections.

All B. melitensis strains were isolated from humans and sheep, and all were B. melliteneis bv. These data demonstrated that B. melitensis strains were the circulating species in this study. A total of 38 Brucella strains were isolated from 16 aborted cows, 20 sheep fetuses, and 2 milk samples from Ili Xinjiang; all of these isolates were identified as B. melitensis [37]. Moreover, Brucella sp. was found in ticks collected from livestock in the Xinjiang Uygur Autonomous Region [38]. Furthermore, B. melitensis biovar 3 was found to be mainly responsible for sheep brucellosis in northwest China [39]. B. melitensis isolates exhibit many single genotypes (ST8) in the most northwest regions of China [40] and have become a regional public health threat to human and livestock populations. The present study revealed that the dominant circulated MLVA-16 genotype was continuously spread throughout different regions, hosts, and times. In a previous study, MLVA-16 resolved 50 B. melitensis strains into 28 genotypes, 15 unique to Xinjiang and 10 common with those in the adjacent country Kazakhstan and neighboring provinces of China [41]. Another study based on WGS-SNP analysis demonstrated that the dominant prevalence species in Xinjiang was B. melitensis bv. 3, and the correlation among isolates was high in both humans and animals [42]. These data provide robust evidence that strains from a common origin continuously expand with the movement of infected animals. It is essential to highlight the need for whole genome sequencing (WGS) to gather more information for improved epidemiological investigations. According to cgSNP and cgMLST analyses showed that different B. melitensis lineages circulate in Kyrgyzstan, all of them belonging to the Eastern Mediterranean group of the global Brucella strains phylogeny with the highest similarity to strains from Turkmenistan, Iran and Turkey [43]. A WGS-SNP analysis of strains in Turkey showed that 11 B. melitensis strains were found to be of the IIb subtype of genotype II associated with the Eastern Mediterranean lineage [44]. Therefore, strengthening genome surveillance and control of ruminant brucellosis is urgently needed to prevent the further spread of human brucellosis; in particular, extensive vaccination programs in regions with high incidence rates are recommended.

Our study provides new insight into the epidemiological evolution of human brucellosis in this area; however, several limitations should be noted. First, the data in this study were analyzed from a public database; thus, the findings potentially only demonstrate part of the epidemic situation. Second, further investigations are needed to explain why previous measures have failed to curb the resurgence of brucellosis. Third, extensive genome-based sequencing analysis is necessary to reveal the transmission patterns of B. melitensis strains in Northwest China.

Conclusions

Human brucellosis is a re-emerging disease in Xinjiang, and the incidence rate significantly increased from 2004 to 2023. In particular, the incidence rates in most counties in South Xinjiang were higher than 2.0/100,000, and human brucellosis has become endemic in South Xinjiang. Furthermore, our analysis revealed that B. melitensis strains from a common origin were the main pathogens that drove the continuous expansion and spread of human brucellosis in Xinjiang. These data underscore that, owing to large-scale livestock farming, human brucellosis has become a serious public health challenge. However, brucellosis surveillance and control are costly and time-consuming; thus, long-term attention, policy support, and sustained stable financial investment are extremely important factors in controlling this disease.

Data availability

Data is provided within the manuscript or supplementary information files.

Abbreviations

APC:

The annual percentage change

AAPC:

The average annual percentage change

LLR:

Log likelihood ratio

DNA:

Deoxyribonucleic acid

PCR:

Polymerase chain reaction

UPGMA:

Unweighted pair group method with arithmetic mean

MLST:

Multi-locus sequence typing

MLVA:

Multiple locus variable-number tandem repeat analysis

MST:

Minimum spanning tree

WGS-SNP:

Whole genome sequencing single-nucleotide polymorphism

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Acknowledgements

We are grateful to all the workers whose studies focused on brucellosis control and surveillance in Xinjiang.

Funding

This study was supported by the National Key Research and Development Program of China (No. 2019YFC1200700 (No. 32095)). The sponsors had no role in the study design, data collection and analysis, decision to publish, or manuscript preparation.

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Authors and Affiliations

  1. National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China

    Zhiguo Liu, Min Yuan & Zhenjun Li

  2. Xinjiang Uygur Autonomous Region Center for Disease Control and Prevention, Urumqi, 830002, China

    Bo Li

  3. National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, China

    Chuizhao Xue

  4. Chinese Center for Disease Control and Prevention, Beijing, 102206, China

    Zhenjun Li, Junling Sun & Canjun Zheng

Authors
  1. Zhiguo Liu
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  2. Bo Li
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  3. Chuizhao Xue
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  4. Min Yuan
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  5. Zhenjun Li
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  6. Junling Sun
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  7. Canjun Zheng
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Contributions

LZG and LB charged epidemiology data analysis, plotted figures, and drafted the manuscript, XCZ and YM performed temporal spatial analysis; LB performed isolated B. melitensis and MLVA genotyping; LZJ, SJL, and ZCJ participated in the design of the study and critically reviewed the manuscript. All authors reviewed the manuscript.

Corresponding authors

Correspondence to Zhenjun Li, Junling Sun or Canjun Zheng.

Ethics declarations

Ethics approval and consent to participate

The study obtained data on human brucellosis cases reported through China’s National Notifiable Disease Reporting System, and the study protocol was approved by the Ethics Committee of the National Institute of Communicable Disease Control and Prevention (Grant No. ICDC-ZM-2024015). All the data are anonymous, and no patients participated in this study. Informed consent to participate was not obtained.

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Not applicable.

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The authors declare no competing interests.

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Liu, Z., Li, B., Xue, C. et al. The continuous expansion and spread of human brucellosis in the Xinjiang Uygur Autonomous Region: evidence from epidemiological and strains’ genotyping-based analysis. BMC Microbiol 25, 181 (2025). https://doiorg.publicaciones.saludcastillayleon.es/10.1186/s12866-024-03731-5

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Keywords

BMC Microbiology

ISSN: 1471-2180

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