An epidemiological study of brucellosis on mainland China during 2004-2018

Molecular epidemiology of Brucella abortus isolated from the environment in Ningxia Hui autonomous region, China

Brucellosis is among the key zoonotic infectious diseases in China, and The Ningxia Hui Autonomous Region represents a major endemic area, and it is one of the main causes of poverty in the region due to illness. In Ningxia, there is substantial research on Brucella melitensis, studies on the molecular epidemiology of Brucella abortus are notably scarce. Consequently, this study aims to undertake pathogenic isolation and molecular epidemiological research on Brucella abortus isolated from the environment in Ningxia, providing insights and evidence to advance the prevention and control measures for brucellosis in the region. Building on traditional pathogenic detection methods, this research employs whole-genome sequencing(WGS) techniques and bioinformatics software to conduct a phylogenetic comparison of Ningxia strains and strains of Brucella abortus from various geographical origins. The results indicate that four Brucella abortus strains are classified as biovar 3 and MLST type ST2. It is shown that the local strains were closer phylogenetic relationships with strains from Asian and European countries. The presence of Brucella abortus in certain environmental sectors of Ningxia indicates a risk of transmission from the environment to animals and subsequently to humans. In conclusion, the Brucella abortus exists in some farming environments in Ningxia, and exists for a long time. Therefore, it is necessary to strengthen the monitoring of the disinfection effect of the farming environment to provide a basis for the forward movement of the gate of brucellosis prevention and control.

A scoping review on the epidemiology and public significance of Brucella abortus in Chinese dairy cattle and humans

Brucellosis, caused by Brucella spp., is a re-emerging One Health disease with increased prevalence and incidence in Chinese dairy cattle and humans, severely affecting animal productivity and public health. In dairy cattle, B. abortus is the primary causative agent although infections with other Brucella species occur occasionally. However, the epidemiological and comparative importance of B. abortus in dairy cattle and humans remains inadequately understood throughout China due to the heterogeneity in locations, quality, and study methods. This scoping review aims to describe the changing status of B. abortus infection in dairy cattle and humans, investigate the circulating Brucella species and biovars, and identify factors driving the disease transmission by retrieving publicly accessible literature from four databases. After passing the prespecified inclusion criteria, 60 original articles were included in the final synthesis. Although the reported animal-level and farm-level prevalence of brucellosis in dairy cattle was lower compared to other endemic countries (e.g. Iran and India), it has been reported to increase over the last decade. The incidence of brucellosis in humans displayed seasonal increases. The Rose Bengal Test and Serum Agglutination Test, interpreted in series, were the most used serological test to diagnose Brucella spp. in dairy cattle and humans. B. abortus biovar 3 was the predominant species (81.9%) and biovar (70.3%) in dairy cattle, and B. melitensis biovar 3 was identified as the most commonly detected strain in human brucellosis cases. These strains were mainly clustered in Inner Mongolia and Shannxi Province (75.7%), limiting the generalizability of the results to other provinces. Live cattle movement or trade was identified as the key factor driving brucellosis transmission, but its transmission pattern remains unknown within the Chinese dairy sector. These knowledge gaps require a more effective One Health approach to be bridged. A coordinated and evidence-based research program is essential to inform regional or national control strategies that are both feasible and economical in the Chinese context.

Real-time polymerase chain reaction detection and surgical treatment of thoracic and lumbar spondylitis due to Brucella infection: two typical case reports

Background

Spondylitis caused by Brucella infection is a rare but challenging condition, and its successful management depends on timely diagnosis and appropriate treatment. This study reports two typical cases of thoracic and lumbar brucellosis spondylitis, highlighting the pivotal roles of real-time polymerase chain reaction (real-time PCR) detection and surgical intervention.

Case presentation

Case 1 involved a 49-year-old male shepherd who presented with a 6-month history of fever (40°C), severe chest and back pain, and 2-week limited lower limb movement with night-time exacerbation. Physical examination revealed tenderness and percussion pain over the T9 and T10 spinous processes, with grade 2 muscle strength in the lower limbs. CT showed bone destruction of the T9 and T10 vertebrae with narrowing of the intervertebral space, whereas MRI demonstrated abnormal signals in the T9-T10 vertebrae, a spinal canal abscess, and spinal cord compression. The Rose Bengal plate agglutination test was positive. Case 2 was a 59-year-old man who complained of severe thoracolumbar back pain with fever (39.0°C) and limited walking for 2 months. He had a 2.5 kg weight loss and a history of close contact with sheep. The Rose Bengal test was positive, and the MRI showed inflammatory changes in the L1 and L2 vertebrae. Diagnosis and treatment: real-time PCR confirmed Brucella infection in both cases. Preoperative antimicrobial therapy with doxycycline, rifampicin, and ceftazidime-sulbactam was administered for at least 2 weeks. Surgical management involved intervertebral foraminotomy-assisted debridement, decompression, internal fixation, and bone grafting under general anesthesia. Postoperative histopathological examination with HE and Gram staining further substantiated the diagnosis. Outcomes: both patients experienced significant pain relief and restored normal lower limb movement at the last follow-up (4-12 weeks) after the intervention.

Conclusion

Real-time PCR detection offers valuable diagnostic insights for suspected cases of brucellosis spondylitis. Surgical treatment helps in infection control, decompression of the spinal cord, and restoration of stability, constituting a necessary and effective therapeutic approach. Prompt diagnosis and comprehensive management are crucial for favorable outcomes in such cases.

Factors influencing length of stay and costs in inpatient cases of human brucellosis as the primary diagnosis over a decade in Beijing, China

Aims

In the year 2021, human brucellosis ranked fifth in terms of the number of cases among all statutorily notifiable infectious diseases in China, thus remaining a significant concern for public health. This study aims to provide insights into the financial burden of human brucellosis by examining hospital stays and associated costs for affected individuals.

Methods

In this retrospective study, we gathered updated data from 467 inpatient cases primarily diagnosed with human brucellosis at eight major tertiary hospitals in Beijing, China, spanning from 2013 to 2023. To comprehensively explore the economic impact on individuals, we not only analyzed the duration of hospital stays and total costs but also examined various charge types, including drug, lab test, medical imaging, medical treatment, surgical procedures, medical supplies and consumables, inpatient bed care, nursing services, and other services costs. Statistical analysis was employed to compare differences among gender, age, ethnicity, type of health insurance, condition at admission, comorbidity index, the performance of surgery, and the site of infection.

Results

Both the length of stay and total cost exhibited significant variations among insurance, surgery, and infection site groups. Utilization categories demonstrated significant differences between patients who underwent surgery and those who did not, as well as across different infection sites. Furthermore, multiple linear regression analysis revealed that the condition at admission, Elixhauser comorbidity index, infection site, and surgery influenced both hospital stay and total cost. In addition, age and insurance type were associated with total costs.

Conclusion

By delving into various utilization categories, we have addressed a significant gap in the literature. Our findings provide valuable insights for optimizing the allocation and management of health resources based on the influencing factors identified in this study.

A comparison of clinical features between neurobrucellosis and tuberculous meningitis

BACKGROUD

This study aims to compare the clinical manifestations, imaging findings, routine tests, biochemistry indicators and cerebrospinal fluid cytology between neurobrucellosis and tuberculous meningitis. The objective is to evaluate the similarities and differences of these two diseases and improve early diagnosis.

METHODS

A comprehensive evaluation was conducted by comparing clinical data, imaging results, routine tests findings, biochemistry indicators and cerebrospinal fluid cytology of patients admitted to the Department of Neurology, the Second Hospital of Hebei Medical University from 2019 to 2021. Statistical analysis was applied to identify significant differences and similarities between the two diseases.

RESULTS

Preliminary analysis demonstrated both diseases commonly present with symptoms such as fever, headache. However, there were no statistical differences between neurobrucellosis and tuberculous meningitis in early clinical data, imaging results, routine tests findings, biochemistry indicators. Further analysis indicates there is a statistically significantly difference in the lymphocyte ratio and neutrophil ratio in the cerebrospinal fluid between the two groups.

CONCLUSIONS

Neurobrucellosis and tuberculous meningitis share similarities in early clinical manifestations, imaging findings and initial cerebrospinal fluid parametes, making early-stage differentiation challenging. The ratio of lymphocytes and neutrophil in the cerebrospinal fluid and a detailed medical history investigation can provide clues for early clinical diagnosis. So the examination of CSF cytology might be a potential to distinguish these two diseases and become a powerful tool in the future.

Seasonal autoregressive integrated moving average (SARIMA) time-series model for milk production forecasting in pasture-based dairy cows in the Andean highlands

Milk production in the Andean highlands is variable over space and time. This variability is related to fluctuating environmental factors such as rainfall season which directly influence the availability of livestock feeding resources. The main aim of this study was to develop a time-series model to forecast milk production in a mountainous geographical area by analysing the dynamics of milk records thorough the year. The study was carried out in the Andean highlands, using time-series models of monthly milk records collected routinely from dairy cows maintained in a controlled experimental farm over a 9-year period (2008-2016). Several statistical forecasting models were compared. The Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and Mean Absolute Percent Error (MAPE) were used as selection criteria to compare models. A relation between monthly milk records and the season of the year was modelled using seasonal autoregressive integrated moving average (SARIMA) methods to explore temporal redundancy (trends and periodicity). According to white noise residual test (Q = 13.951 and p = 0.052), Akaike Information Criterion and MAE, MAPE, and RMSE values, the SARIMA (1, 0, 0) x (2, 0, 0)12 time-series model resulted slightly better forecasting model compared to others. In conclusion, time-series models were promising, simple and useful tools for producing reasonably reliable forecasts of milk production thorough the year in the Andean highlands. The forecasting potential of the different models were similar and they could be used indistinctly to forecast the milk production seasonal fluctuations. However, the SARIMA model performed the best good predictive capacity minimizing the prediction interval error. Thus, a useful effective strategy has been developed by using time-series models to monitor milk production and alleviate production drops due to seasonal factors in the Andean highlands.

Synergistic driving effects of risk factors on human brucellosis in Datong City, China: A dynamic perspective from spatial heterogeneity

Brucellosis is a highly contagious zoonotic and systemic infectious disease caused by Brucella, which seriously affects public health and socioeconomic development worldwide. Particularly, in China accumulating eco-environmental changes and agricultural intensification have increased the expansion of human brucellosis (HB) infection. As a traditional animal husbandry area adjacent to Inner Mongolia, Datong City in northwestern China is characterized by a high HB incidence, demonstrating obvious variations in the risk pattern of HB infection in recent years. In this study, we built Bayesian spatiotemporal models to detect the transfer of high-risk clusters of HB occurrence in Datong from 2005 to 2020. Geographically and Temporally Weighted Regression and GeoDetector were employed to investigate the synergistic driving effects of multiple potential risk factors. Results confirmed an evident dynamic expansion of HB from the east to the west and south in Datong. The distribution of HB showed a negative correlation with urbanization level, economic development, population density, temperature, precipitation, and wind speed, while a positive correlation with the normalized difference vegetation index, and grassland/cropland cover areas. Especially, the local animal husbandry and related industries imposed a large influence on the spatiotemporal distribution of HB. This work strengthens the understanding of how HB spatial heterogeneity is driven by environmental factors, through which helpful insights can be provided for decision-makers to formulate and implement disease control strategies and policies for preventing the further spread of HB.

A participatory approach to understand the attitudes and perceptions towards priority endemic cattle diseases among dairy farmers and animal health experts in Henan province, China

The dairy industry is threatened by a variety of endemic diseases and emerging diseases, and various control programs have been initiated in China. The increased application of evidence to policymaking can help improve the efficiency of disease control programs; however, the relevant research literature is currently lacking. The objective of this study was to gain an in-depth understanding of the attitudes and perceptions towards priority endemic diseases among dairy farmers and animal health experts by taking Henan province of China as the example and using semi-structured interviews and focus group discussions, respectively. This study involved 24 farmers and 27 animal health experts from December 2019 to January 2021. The diseases considered by farmers to be of significance to their animals are different from those considered priorities by the participating experts and the government list. From the perspective of the individual farmers, the effects of zoonotic disease risks such as bovine brucellosis and tuberculosis appear to be less pronounced than "visible" losses at the farm level, contrary to the opinion of experts. Participating experts believed that poor on-farm biosecurity measures posed challenges to the control and eradication of priority endemic diseases; however, there are gaps in farmers' understanding of biosecurity principles, and low motivations to take such disease prevention measures. Several other challenges to the control and eradication of priority endemic diseases also emerged in the data, including the lack of diagnostic tools applicable in the field as well as differential diagnostic tools to differentiate natural infection from vaccination, lack of effective and commercially available vaccines against single or multiple pathogen(s) or new genotypes/serotypes, weak early warning and information networks and insufficient economic compensation. A holistic understanding of people's perceptions of disease control would facilitate the implementation of inclusive and engaging disease control strategies, thereby increasing the efficiency of disease control.

Analysis of Clinical Characteristics and Blood Cell in Adult Patients with Brucella Bloodstream Infection of Different Blood Groups

The clinical manifestations and blood cell varied among patients with Brucella bloodstream infection. This study aimed to explore the clinical characteristics and blood cells of adult Brucella bloodstream infection patients with different ABO blood groups. This study retrospectively analyzed 77 adult Brucella bloodstream infection patients. Demographic characteristics, clinical manifestations, laboratory data, and blood cell differences of adult Brucella bloodstream infection patients were analyzed. For Brucella bloodstream infection patients, the blood group was distributed as: B > O > A > AB. The main symptoms of the patients were fever (94.81%), and 56 patients (72.70%) were complicated with liver injury. The highest proportion of liver injury was 93.33% in patients with blood group A and 52.38% in blood group O (P < 0.05). There were 19 cases (24.68%) with spondylitis, 30 cases (38.96%) with anemia, 28 (36.36%) with leukopenia, 16 (20.78%) with thrombocytopenia, without notable differences between different blood groups (P > 0.05). The proportion of lymphocytes in patients with the AB blood group was the highest (39.46 ± 11.21), and in patients with the B blood group was the lowest (28.00 ± 12.10), with significant difference between different blood groups (P < 0.05). Patients with Brucella bloodstream infection with blood group A were more prone to liver injury than those with blood group O. More attention should be paid to liver injury when receiving patients with blood group A. The proportion of lymphocytes in patients with blood group B and AB was different, suggesting that they may have different immune states.

Driving role of climatic and socioenvironmental factors on human brucellosis in China: machine-learning-based predictive analyses

BACKGROUND

Brucellosis is a common zoonotic infectious disease in China. This study aimed to investigate the incidence trends of brucellosis in China, construct an optimal prediction model, and analyze the driving role of climatic factors for human brucellosis.

METHODS

Using brucellosis incidence, and the socioeconomic and climatic data for 2014-2020 in China, we performed spatiotemporal analyses and calculated correlations with brucellosis incidence in China, developed and compared a series of regression and Seasonal Autoregressive Integrated Moving Average X (SARIMAX) models for brucellosis prediction based on socioeconomic and climatic data, and analyzed the relationship between extreme weather conditions and brucellosis incidence using copula models.

RESULTS

In total, 327,456 brucellosis cases were reported in China in 2014-2020 (monthly average of 3898 cases). The incidence of brucellosis was distinctly seasonal, with a high incidence in spring and summer and an average annual peak in May. The incidence rate was highest in the northern regions' arid and continental climatic zones (1.88 and 0.47 per million people, respectively) and lowest in the tropics (0.003 per million people). The incidence of brucellosis showed opposite trends of decrease and increase in northern and southern China, respectively, with an overall severe epidemic in northern China. Most regression models using socioeconomic and climatic data cannot predict brucellosis incidence. The SARIMAX model was suitable for brucellosis prediction. There were significant negative correlations between the proportion of extreme weather values for both high sunshine and high humidity and the incidence of brucellosis as follows: high sunshine, [Formula: see text] = -0.59 and -0.69 in arid and temperate zones; high humidity, [Formula: see text] = -0.62, -0.64, and -0.65 in arid, temperate, and tropical zones.

CONCLUSIONS

Significant seasonal and climatic zone differences were observed for brucellosis incidence in China. Sunlight, humidity, and wind speed significantly influenced brucellosis. The SARIMAX model performed better for brucellosis prediction than did the regression model. Notably, high sunshine and humidity values in extreme weather conditions negatively affect brucellosis. Brucellosis should be managed according to the "One Health" concept.

Case report: Brucellosis with rare multiple pulmonary nodules in a depressed patient

Background

Brucellosis is a zoonotic disease that threatens public health and creates an economic burden. Unfortunately, it is often overlooked in developing countries, with misdiagnosis causing negative impacts on those with low income. Although the symptoms of brucellosis are commonly reported as fever and fatigue, rare pulmonary, and psychiatric involvements should also be considered. We present the first brucellosis patient in China with multiple pulmonary nodules and depression. Furthermore, this report highlights the importance of collecting patient history in epidemic areas of brucellosis.

Case presentation

We report the case of a 40-year-old woman with intermittent fever for 2 months and gradually accompanied by chills, dry cough, arthralgia, and fatigue. The patient was also diagnosed with depression after fever. She received symptomatic treatment at a regional hospital; however, there was no significant symptom relief. She suddenly developed hemoptysis 1 day prior to arrival at our hospital, where we discovered that her liver, spleen, neck, and axillary lymph nodes were enlarged, and there were multiple nodules in both lungs. The patient was eventually diagnosed with brucellosis after the serum agglutination test and received antibiotic therapy, which provided symptom relief.

Conclusion

This report describes a case of brucellosis with uncommon multipulmonary nodules and depression in China. This study has widened the evidence of respiratory involvement due to brucellosis. Second, it demonstrates the importance of collecting a comprehensive medical history, especially in epidemic areas. In conclusion, for febrile patients with pulmonary nodules and depression, especially in endemic areas, brucellosis should be considered.

A case study investigating the effects of emergency vaccination with Brucella abortus A19 vaccine on a dairy farm undergoing an abortion outbreak in China

Brucellosis is an important zoonosis that results in substantial economic losses to the livestock industry through abortions and reduced milk yield. This study investigated an abortion outbreak in a dairy herd and then explored the effects of emergency vaccination with Brucella abortus A19 vaccine on the incidence of abortion and milk yield. A full dose of vaccine (6 × 1010—12 × 1010 colony forming units, CFU) was administered subcutaneously to calves and non-pregnant heifers, and a reduced dose (6 × 108—12 × 108 CFU) to adult cows and pregnant replacement heifers. Rose Bengal Test was used to screen Brucella infection status and then positive samples were tested with a C-ELISA. Animals that tested positive for both tests were considered positive to Brucella spp. The animal-level seroprevalence of brucellosis was 23.1% (95% CI: 17.0, 30.2), and the attributable fraction of abortions in seropositive animals was 89.1% (95% CI: 64.3, 96.7). The odds of seropositivity were significantly higher in cows that aborted compared to cows that calved normally (OR = 21.4, 95% CI: 4.4, 168.4). Cows in sheds A2 and C1 were 10.2 (95% CI: 1.4, 128.0) and 17.0 (95% CI: 2.8, 190.3) times more likely to be seropositive than cows in shed B1. Antibodies were not detectable in most heifers 12 months post-vaccination. The effectiveness of the vaccine in preventing abortions was estimated to be 56.8% (95% CI: 15.8, 77.8) for the entire herd, but increased to 86.7% (95% CI: 4.4, 98.1) when only primiparous heifers were considered. Furthermore, a significant increase in the average herd 305-day milk yield one-year after vaccination was also observed relative to that in the previous three years. It is concluded that emergency vaccination of a dairy herd undergoing an abortion outbreak with the A19 vaccine effectively reduced the incidence of abortion and indirectly increased milk yield one-year after vaccination.

Clinical Features of Human Brucellosis and Risk Factors for Focal Complications: A Retrospective Analysis in a Tertiary-Care Hospital in Beijing, China

Purpose

Brucellosis is an ongoing zoonotic disease in China, but there are few data in Beijing. This study was designed to illustrate clinical characteristics of patients with brucellosis in Beijing, China and explore the risk factors for focal brucellosis.

Patients and Methods

Data of patients with brucellosis were retrospectively collected from the patients’ electronic medical records in Beijing Youan Hospital during 2010 to 2021, including epidemiological, demographic and clinical features. Risk factors for focal brucellosis were identified by multivariable logistic regression models.

Results

A total of 197 patients were included in the study, with 165 (83.8%) cases in acute phase and 32 (16.2%) cases in chronic phase. Patients in acute phase were more likely to have splenomegaly (24.2% vs 3.1%, p=0.007) than those in chronic phase, but had less arthralgia (62.4% vs 81.3%, p=0.040). The median level of alanine aminotransferase (36.9 vs 20.7, p=0.001) was higher in patients at acute stage than those at chronic stage. Of all the patients, 76 (38.6%) were reported with focal complications, including 16 (8.1%) peripheral arthritis, 36 (18.3%) spondylitis, 17 (8.6%) epididymoorchitis, 8 (4.1%) meningitis and 3 (1.3%) endocarditis. Additionally, male (OR 2.76, 95% CI 1.15–6.64, p = 0.023), arthralgia (OR 6.23, 95% CI 2.36–16.43, p < 0.001) and higher level of platelets (OR 1.01, 95% CI 1.00–1.01, p < 0.001) were the independent risk factors for focal brucellosis.

Conclusion

The control of human brucellosis still cannot be ignored due to the re-emerging cases in Beijing, which are more likely to present splenomegaly and abnormal liver function in acute phase. Moreover, male, arthralgia and high level of platelets were the independent risk factors for focal brucellosis.

Treatment of Severe Refractory Thrombocytopenia in Brucellosis with Eltrombopag: A Case Report

Brucellosis is a zoonotic disease. Severe refractory thrombocytopenia caused by brucellosis is very rare and easily misdiagnosed. We reported a 5-year-old girl who developed severe refractory thrombocytopenia secondary to brucellosis. The first-line treatment including corticosteroids and intravenous immunoglobulin did not elevate her platelets, but eltrombopag worked well and her platelet count recovered rapidly.

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

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.

Seroprevalence trend of human brucellosis and MLVA genotyping characteristics of Brucella melitensis in Shaanxi Province, China, during 2008-2020

In this study, a total of 179,907 blood samples from populations with suspected Brucella spp. infections were collected between 2008 and 2020 and analyzed by the Rose Bengal plate test (RBPT) and serum agglutination test (SAT). Moreover, conventional biotyping, B. abortus-melitensis-ovis-suis polymerase chain reaction (AMOS-PCR), and multiple-locus variable-number tandem repeat analysis (MLVA) was applied to characterize the isolated strains. A total of 8103 (4.50%) samples were positive in RBPT, while 7705 (4.28%, 95% confidence interval (CI) 4.19-4.37) samples were positive in SAT. There was a significant difference in seroprevalence for human brucellosis over time, in different areas and different cities (districts) (χ² = 2 = 32.23, 1984.14, and 3749.51, p < .05). The highest seropositivity (8.22% (4, 965/60393; 95% CI 8.00-8.44) was observed in Yulin City, which borders Inner Mongolia, Ningxia, and Gansu Province, China, regions that have a high incidence of human brucellosis. Moreover, 174 Brucella strains were obtained, including nine with B. melitensis bv. 1, 145 with B. melitensis bv. 3, and 20 with B. melitensis variants. After random selection, 132 B. melitensis were further genotyped using MLVA-16. The 132 strains were sorted into 100 MLVA-16 genotypes (GTs) (GT 1-100), 81 of which were single GTs represented by singular independent strains. The remaining 19 shared GTs involved 51 strains, and each GT included two to seven isolates from the Shaan northern and Guanzhong areas. These data indicated that although sporadic cases were a dominant epidemic characteristic of human brucellosis in this province, more than 38.6% (51/132) outbreaks were also found in the Shaan northern area and Guanzhong areas. The 47 shared MLVA-16 GTs were observed in strains (n = 71) from this study and strains (n = 337) from 19 other provinces of China. These data suggest that strains from the northern provinces are a potential source of human brucellosis cases in Shaanxi Province. It is urgent to strengthen the surveillance and control of the trade and transfer of infected sheep among regions.

Changes in the epidemiological characteristics of human brucellosis in Shaanxi Province from 2008 to 2020

In the present study, surveys of case numbers, constituent ratios, conventional biotyping, and multilocus sequence typing (MLST) were applied to characterize the incidence rate and epidemiological characteristics of human brucellosis in Shaanxi Province, China. A total of 12,215 human brucellosis cases were reported during 2008-2020, for an annual average incidence rate of 2.48/100,000. The most significant change was that the county numbers of reported cases increased from 36 in 2008 to 84 in 2020, with a geographic expansion trend from northern Shaanxi to Guanzhong, and southern Shaanxi regions; the incidence rate declined in previous epidemic northern Shaanxi regions while increasing each year in Guanzhong and southern Shaanxi regions such as Hancheng and Xianyang. The increased incidence was closely related to the development of large-scale small ruminants (goats and sheep) farms in Guanzhong and some southern Shaanxi regions. Another significant feature was that student cases (n = 261) were ranked second among all occupations, accounting for 2.14% of the total number of cases, with the majority due to drinking unsterilized goat milk. Three Brucella species were detected (B. melitensis (bv. 1, 2, 3 and variant), B. abortus bv. 3/6, and B. suis bv. 1) and were mainly distributed in the northern Shaanxi and Guanzhong regions. Three known STs (ST8, ST2, and ST14) were identified based on MLST analysis. The characteristics that had not changed were that B. melitensis strains belonging to the ST8 population were the dominant species and were observed in all nine regions during the examined periods. Strengthened human and animal brucellosis surveillance and restriction of the transfer of infected sheep (goats) as well as students avoiding drinking raw milk are suggested as optimal control strategies.

Evaluating active versus passive sources of human brucellosis in Jining City, China

Human brucellosis (HB) remains a serious public health concern owing to its resurgence across the globe and specifically in China. The timely detection of this disease is the key to its prevention and control. We sought to describe the differences in the demographics of high-risk populations with detected cases of HB contracted from active versus passive sources. We collected data from a large sample population from January to December 2018, in Jining City, China. We recruited patients that were at high-risk for brucellosis from three hospitals and Centers of Disease Control and Prevention (CDCs). These patients were classified into two groups: the active detection group was composed of individuals receiving brucellosis counseling at the CDCs; the passive detection group came from hospitals and high-risk HB groups. We tested a total of 2,247 subjects and 13.3% (299) presented as positive for HB. The positive rates for active and passive detection groups were 20.5% (256/1,249) and 4.3% (43/998), respectively (p < 0.001). The detection rate of confirmed HB cases varied among all groups but was higher in the active detection group than in the passive detection group when controlled for age, sex, ethnicity, education, career, and contact history with sheep or cattle (p < 0.05). Males, farmers, those with four types of contact history with sheep or cattle, and those presenting fever, hyperhidrosis and muscle pain were independent factors associated with confirmed HB cases in multivariate analysis of the active detection group. Active detection is the most common method used to detect brucellosis cases and should be applied to detect HB cases early and avoid misdiagnosis. We need to improve our understanding of brucellosis for high-risk populations. Passive HB detection can be supplemented with active detection when the cognitive changes resulting from brucellosis are low. It is important that healthcare providers understand and emphasis the timely diagnosis of HB.

Human brucellosis epidemiology in the pastoral area of Hulun Buir city, Inner Mongolia autonomous region, China, between 2003 and 2018

Human brucellosis represents a serious public health concern in Hulun Buir and requires a comprehensive epidemiologic analysis to define adapted control measures. The present study describes the case numbers, constituent ratios and incidence rate of human brucellosis. Conventional biotyping, that is abortus, melitensis, ovis and suis (AMOS)-PCR and multi-locus variable-number tandem repeat analysis (MLVA) were used to characterize the Brucella strains. Between 2003 and 2018, a total of 23,897 human brucellosis cases were reported, with an incidence rate of 56.03/100,000, which is 20 times higher than the country's average incidence. This incidence rate increased year after year, culminating in 2005 and decreased between 2011 and 2018. Because Hulun Buir relies on a nomadic livestock rearing system, brucellosis spreads easily among different animal species and humans. In Xin Barag Left Banner and Xin Barag Right Banner, the incidence rates were, respectively, 226.54/100,000 and 199.10/100,000, exceeding those observed in other areas. Most of the cases occurred in the 25- to 45-year-old group, accounting for 65.74% of the cases (15,709/23,897), and among farmers, accounting for 66.71% (15,942/23,897). The male to female incidence ratio was 2.67:1. The higher incidence in younger people and the large gender ratio reflected the unique traditional production and lifestyle of nomads. Most reported cases were observed from April to June, indicating that more than 40% of the cases were related to the delivery of domestic livestock. The biotyping showed that the 44 isolated strains were all B. melitensis, including 12 Brucella melitensis biovar (bv) 1 and 32 B. melitensis bv. 3. The strains displayed a genetic similarity of 80%-100%. Our hypothesis is that human brucellosis outbreak in this region may be originating from a limited source of infection, so further investigation is necessary. The epidemic situation of human brucellosis in Hulun Buir is extremely serious, strengthened surveillance and control in animals' brucellosis should be priority.