Prevalence of bovine leukemia in 1983-2019 in China: A systematic review and meta-analysis.

Bovine leukemia is a chronic, progressive, contagious tumor disease characterized by malignant lymphoid cell hyperplasia and systemic lymphadenopathy, and is caused by bovine leukemia virus (BLV). The disease affects almost all countries and regions where livestock are raised, and may even be a potential zoonotic disease. Monitoring and early prevention of bovine leukemia is very important. Therefore, we conducted this meta-analysis, the first of its type in the country, to estimate the prevalence of bovine leukemia in 1983-2019 in China. We included a total of 35 publications reported in 1983-2019 from the PubMed, ScienceDirect, Chinese Web of Knowledge (CNKI), VIP Chinese, and Wan Fang databases. In those articles, a total of 34,954 cattle had been tested, of which 4701 were positive for BLV infection. The estimated pooled BLV prevalence was 10.0% (4701/34,954). Subgroup analysis showed that there were significant differences for sampling years, detection methods, and age. BLV prevalence was highest in the following subgroups: sampled before 1985 (38.5%, 437/1134), age 3-5 years (22.5%, 231/1044), and detected by PCR (17.9%, 1228/5100). Regarding geographic factors, there were significant differences in the latitude and elevation subgroups. BLV prevalence was lowest in the subgroups of 20-30° latitude (3.3%, 255/5069) 200-1000 m altitude (2.2%, 560/11,990). We also analyzed other subgroups such as region, variety, breeding method, precipitation, humidity, and temperature, however, the differences were not significant. Our research indicated that the BLV was still prevalent in some of areas in China. We recommend strengthening the testing of cattle aged >1 year and using flexible testing methods such as PCR to control the prevalence of bovine leukemia and to prevent persistent infection.

Mink Aleutian disease seroprevalence in China during 1981-2017: A systematic review and meta-analysis.

Mink Aleutian disease (AMD) is the first of the three major diseases of fur animals. It is a common immunosuppressive disease in mink farms worldwide, which seriously endangers the development of the mink farming industry. Strengthening the understanding of the positive serum rate and spatial distribution of AMD is of great significance for the prevention and control of disease caused by the Aleutian virus. Therefore, we conducted a systematic review and meta-analysis to assess the seroprevalence of AMD in China. We extracted 45 studies related to the seroprevalence of Chinese AMD, with samples taken between 1981 and 2017. Our systematic review and meta-analysis results show that, during the selected period, the overall positive rate of AMD in China was 55.3% (95% CI 48.5-62.0). The results from subgroups analysis of the potential risk factors showed that the seroprevalence rate of AMD in China in the past 36 years rose from 48% (95% CI 37.0-60.5) in 1981-2009 to 61.4% (95% CI 43.6-79.3) in 2010-2017. The date of the spatial difference in AMD seroprevalence indicated that AMD seroprevalence was unevenly distributed in different regions: the number of mink in eastern China and northeastern China was relatively high, and the seroprevalence rates were 57.9%, (95% CI 46.2-69.7) and 61.3% (95% CI 53.1-69.5), respectively. Central China had the highest seroprevalence rate of AMD at 69.8% (95% CI 64.4-75.2). At the provincial level, the AMD seroprevalence rate in Jiangsu was as high as 96% (95% CI 94.1-97.8), and the AMD seroprevalence rate in Shaanxi was the lowest at 22.1% (95% CI 20.3-23.9). This suggested that the AMD seroprevalence rate in China was unevenly distributed. In other subgroups, the positive rate of AMD in adult mink was higher than in juvenile mink. This implied that the high prevalence of AMD in China was caused by multiple factors. The meta-regression results indicated that the detection method subgroup (P = 0.008) may be the source of heterogeneity. Our data system evaluated the prevalence of Aleutian disease in China in the last 37 years and a preliminary discussion on the risk factors of AMD. It may help prevent and control AMD in China. It is recommended to conduct further epidemiological testing and develop a comprehensive testing plan to determine the risk factors associated with Aleutian disease and improve the Aleutian disease control strategy.

Prevalence of bovine viral diarrhea virus (BVDV) in yaks between 1987 and 2019 in mainland China: A systematic review and meta-analysis.

BACKGROUND: Bovine viral diarrhea is an infectious disease that causes symptoms such as bovine diarrhea and abortion. It can cause severe losses to the animal husbandry, and the overall epidemic situation of yak's BVDV in China is unclear. Meta-analysis can reveal the basic epidemic situation of BVDV in different yak distribution areas in China, and estimate potentially related factors, to pave the way for clarifying the epidemic situation of yak in the domestic scope. METHODS: We proceeded to a systematic review and meta-analysis of data from papers on the BVDV incidence and prevalence in yaks in China by searching PubMed, ScienceDirect, Chinese Web of Knowledge (CNKI), Wanfang, and Chongqing VIP for publication from 1987 to 2019. We excluded reviews and duplicate studies, 24 studies denouncing the prevalence of BVDV in yak in China were selected upon our inclusion criterion finally. We estimated the pooled prevalence of BVDV infection in yaks by a random-effects model and evaluated its overall infection burden in China. FINDINGS: In total, the pooled prevalence of BVDV in yaks in China was 36.0% (95% CI 25.6%-46.4%) based on the data obtained from 13,446 yaks, by detecting antigens and antibodies. The highest BVDV positive rate in yak reached 67.5% in Xinjiang province of China. The prevalence in the six provinces of China was validated to be quite variable (24.4%-67.5%) and reached 369% in yaks of northwest China. Besides, the BVDV antigen-positive rate was estimated at 13.8% (95% CI 8.6%-19.0%) based on 5 studies, comparatively, the pooled BVDV antibody-based on 18 studies was about 32.9% (95% CI 24.6%-41.2%) in China. INTERPRETATION: This systematic review and meta-analysis firstly established an estimated prevalence of BVDV in yaks in China, as a whole, and estimates potential relevant factors, including geographic location, publication year, age, detection methods, etc., Our findings suggest that the scientific community or decision-makers can formulate corresponding prevention and control plans based on potential risk factors.

Worldwide Swine Tuberculosis-Positive Rate and Associated Risk Factors, 1966-2020: A Systematic Review and Meta-Analysis.

Background: Tuberculosis (TB) is a chronic, zoonotic infectious disease caused by Mycobacterium tuberculosis that infects not only humans but also animals such as pigs, cows, buffaloes, sheep, and goats. Among them, pigs are one of the main food animals in the world. If pigs are infected with M. tuberculosis, meat products will be negatively affected, causing economic losses to the livestock industry. There is currently no systematic epidemiological assessment of swine TB in the world, so it is important to know the prevalence of swine, and these data are currently lacking, so we performed a statistical analysis. Results: We searched 6791 articles and finally included data from 35,303 pigs from 15 countries or territories, showing a combined prevalence of TB in pigs of 12.1% (95% confidence interval [CI]: 9.2 to 15.9). Among them, the prevalence rate of swine TB in Europe was 15.2% (95% CI: 11.1 to 20.7, 2491/25,050), which was higher compared with other continents, and the difference was significant; the positive rate of PCR method was higher in the detection method subgroup, which was 15.7% (95% CI: 8.0 to 31.0, 376/2261); Mycobacterium bovis was detected in pigs in the M. tuberculosis typing group (9.5%, 95% CI: 6.7 to 13.5, 1364/21,430). The positive rate is higher compared with Mycobacterium capris. Conclusion: This systematic review and meta-analysis is the first to determine the global prevalence of TB in swine herds. Although the seroprevalence of swine TB in this article is very low, the harm of TB cannot be ignored. It is important to take effective control and preventive measures to stop the spread of TB to reduce the impact of diseased pigs on animal husbandry and human health.

Prevalence of Mycobacterium bovis in deer in mainland China: a systematic review and meta-analysis.

Background: Deer tuberculosis is a chronic zoonotic infectious disease, despite the existence of socio-economic and zoonotic risk factors, but at present, there has been no systematic review of deer tuberculosis prevalence in mainland China. The aim of this meta-analysis was to estimate the overall prevalence of deer TB in mainland China and to assess possible associations between potential risk factors and the prevalence of deer tuberculosis. Methodology: This study was searched in six databases in Chinese and English, respectively (1981 to December 2023). Four authors independently reviewed the titles and abstracts of all retrieved articles to establish the inclusion exclusion criteria. Using the meta-analysis package estimated the combined effects. Cochran's Q-statistic was used to analyze heterogeneity. Funnel plots (symmetry) and used the Egger's test identifying publication bias. Trim-and-fill analysis methods were used for validation and sensitivity analysis. we also performed subgroup and meta-regression analyses. Results: In this study, we obtained 4,400 studies, 20 cross-sectional studies were screened and conducted a systematic review and meta-analysis. Results show: The overall prevalence of tuberculosis in deer in mainland China was 16.1% (95% confidence interval (CI):10.5 24.6; (Deer tuberculosis infected 5,367 out of 22,215 deer in mainland China) 5,367/22215; 1981 to 2023). The prevalence in Central China was the highest 17.5% (95% CI:14.0-21.9; 63/362), and among provinces, the prevalence in Heilongjiang was the highest at 26.5% (95% CI:13.2-53.0; 1557/4291). Elaphurus davidianus was the most commonly infected species, with a prevalence of 35.3% (95% CI:18.5-67.2; 6/17). We also assessed the association between geographic risk factors and the incidence of deer tuberculosis. Conclusion: Deer tuberculosis is still present in some areas of China. Assessing the association between risk factors and the prevalence of deer tuberculosis showed that reasonable and scientific-based breeding methods, a suitable breeding environment, and rapid and accurate detection methods could effectively reduce the prevalence of deer tuberculosis. In addition, in the management and operation of the breeding base, improving the scientific feed nutrition standards and establishing comprehensive standards for disease prevention, immunization, quarantine, treatment, and disinfection according to the breeding varieties and scale, are suggested as ways to reduce the prevalence of deer tuberculosis.

The effect of fibroblast growth factor 21 on a mouse model of bovine viral diarrhea.

Previously, we researched that bovine viral diarrhea virus (BVDV) induced a very significant increase in fibroblast growth factor 21 (FGF21) expression in mouse liver and that FGF21 was increased in the peripheral blood of BVD cattle and BVD mice. To determine the role of FGF21 in relieving clinical symptoms and inhibiting the intestinal damage caused by BVDV in BVD development in mice, BALB/c mice were intraperitoneally injected with cytopathic biotype (cp) BVDV-LS01 (isolated and identified by our group) to establish a BVD mouse model. The role of FGF21 in the BVD mouse model was investigated by injecting the mice with FGF21. The animals were divided into control, BVDV challenge, BVDV + FGF21, BVDV + FGF21Ab (anti-FGF21 antibody), and BVDV + IgG (immunoglobulin G) groups. The stool consistency, the degree of bloody diarrhea, histopathological changes, inflammatory cell infiltration, weight loss percentage, and detection of BVDV in the feces of the mice were examined, and the pathological changes and inflammatory cytokine expression were analyzed. The results showed that after BVDV challenge, the average BVD mouse model score of the BVDV mice was 11.6 points. In addition to mild diarrhea and tissue damage, BVDV was detected in the stools of 13 BVDV mice. Only two mice in the control group had scores (both, 1 point each). The comprehensive scoring results demonstrated the successful establishment of the BVD mouse model. FGF21 alleviated the clinical symptoms in the BVD mice and significantly improved weight loss. Furthermore, FGF21 inhibited the BVDV-induced leukocyte, platelet, and lymphocyte reduction while inhibiting the expression of BVDV-induced inflammatory factors. In the BVD mice, FGF21 promoted duodenal epithelial cell proliferation, thereby significantly improving the damage to the cells. In conclusion, FGF21 exerted a good therapeutic effect on the BVD mouse model.

Prevalence of Eimeria Spp. Among Goats in China: A Systematic Review and Meta-Analysis.

Eimeria spp. infection can cause weight loss in goats, and severe cases can lead to the death of lambs, resulting in economic losses to the goat industry. To explore the pooled prevalence of Eimeria spp. in goats in China, we obtained 70 related publications from five databases and conducted a meta-analysis. In China, the combined prevalence of Eimeria spp. in goats was 78.7% (95% confidence interval (CI): 68.15-87.67). Among them, the most serious infections occurred in Northeast China (88.0%, 95% CI: 83.54-91.86). The main Eimeria species were E. alijevi (43.7%, 95% CI: 29.53-58.45), E. arloingi (49.7%, 95% CI: 34.83-64.49), E. christenseni (41.2%, 95% CI: 27.07-56.16), and E. ninakohlyakimovae (35.9%, 95% CI: 21.02-52.31). In the sampling year subgroup, 2006 or later presented a lower prevalence (75.3%, 95%CI: 58.72-88.72). In terms of age, the point estimate for young goats (≤ 1 year) was higher (89.9%, 95% CI: 80.82-96.48). The Float (NaCl) method showed the lowest prevalence of Eimeria spp. in goats (75.9%, 95%CI: 62.00-87.46). In the season subgroup, the highest prevalence was in summer (81.5%, 95%CI: 49.62-99.18). Female goats presented a higher prevalence of Eimeria spp. infection than male goats (70.7%, 95%CI: 27.90-98.96). The prevalence was lower in the intensive feeding model (77.4%, 95%CI: 66.56-86.67) and higher in free feeding goats (79.4%, 95%CI: 66.46-89.92). In addition, we also analyzed the potential relationship between geographical factors and the prevalence of Eimeria spp. infection in goats in China. Our findings suggested that Eimeria spp. infection in goats is widespread in China. Despite the overall downward trend, this infection cannot be ignored. We recommend that breeders use anticoccidial drugs to prevent and treat this disease, while improving the feeding conditions and managemental practices to reduce the economic losses caused by Eimeria infection to the goat industry.

Prevalence of bovine viral diarrhea virus in cattle between 2010 and 2021: A global systematic review and meta-analysis.

Background: Bovine viral diarrhea is one of the diseases that cause huge economic losses in animal husbandry. Many countries or regions have successively introduced eradication plans, but BVDV still has a high prevalence in the world. This meta-analysis aims to investigate the prevalence and risk factors of BVDV in the world in recent 10 years, and is expected to provide some reference and theoretical basis for BVDV control plans in different regions. Method: Relevant articles published from 2010 to 2021 were mainly retrieved from NCBI, ScienceDirect, Chongqing VIP, Chinese web of knowledge (CNKI), web of science and Wanfang databases. Results: 128 data were used to analyze the prevalence of BVDV from 2010 to 2021. BVDV antigen prevalence rate is 15.74% (95% CI: 11.35-20.68), antibody prevalence rate is 42.77% (95% CI: 37.01-48.63). In the two databases of antigen and antibody, regions, sampling time, samples, detection methods, species, health status, age, sex, breeding mode, and seasonal subgroups were discussed and analyzed, respectively. In the antigen database, the prevalence of dairy cows in the breed subgroup, ELISA in the detection method subgroup, ear tissue in the sample subgroup, and extensive breeding in the breeding mode were the lowest, with significant differences. In the antibody database, the prevalence rate of dairy cows in the breed subgroup and intensive farming was the highest, with a significant difference. The subgroups in the remaining two databases were not significantly different. Conclusion: This meta-analysis determined the prevalence of BVDV in global cattle herds from 2010 to 2021. The prevalence of BVDV varies from region to region, and the situation is still not optimistic. In daily feeding, we should pay attention to the rigorous and comprehensive management to minimize the spread of virus. The government should enforce BVDV prevention and control, implement control or eradication policies according to local conditions, and adjust the policies in time.

Meta-analysis of the prevalence of Echinococcus in dogs in China from 2010 to 2019.

BACKGROUND: Echinococcosis (canine Echinococcus disease) is a neglected tropical disease that causes serious public harm. Dogs, as a terminal host of Echinococcus spp., are a key part of the Echinococcus epidemic. Echinococcosis spreads easily in humans and animals in some areas of China and it is therefore necessary to fully understand the prevalence of Echinococcus spp. in dogs. METHODOLOGY/PRINCIPAL FINDINGS: PubMed, ScienceDirect, Chongqing VIP, China National Knowledge Infrastructure (CNKI), and WanFang databases were searched for relevant articles published in the past 10 years. A final total of 108 studies were included. The overall prevalence of Echinococcus spp. in dogs in China was 7.3%, with the highest point estimate found in sampling year 2015 (8.2%) and publication year 2015 (16.5%). Northwestern China (7.9%) had the highest infection rate in China. Qinghai Province (13.5%) showed the highest prevalence among the 11 provinces we included. We also found that geographical and climatic factors are related to the incidence of canine echinococcosis. We further investigated the source of heterogeneity by analysis of subgroups (sampling district, detection method, dog type, season, parasite species, medication, and study quality level). CONCLUSIONS/SIGNIFICANCE: Our research indicated that Echinococcus spp. were still prevalent in some areas in China. More localized prevention and control policies should be formulated, including improving drinking water hygiene and strengthening hygiene promotion. We recommend the rational use of anti-Echinococcus drugs. In addition, treatment of livestock offal and feces and improving the welfare of stray dogs may play an important role in reducing canine Echinococcus infections.

Prevalence of Chlamydia in Pigs in China from 1985 to 2020: A Systematic Review and Meta-Analysis.

Chlamydia is a small gram-negative (G-) microorganism that can be dangerous to human and animals. In this study, we conducted a systematic review and meta-analysis of Chlamydia infection in swine in China. From PubMed, ScienceDirect, Chinese Web of knowledge (CNKI), VIP Chinese journal database, and Wanfang database, we collected a total of 72 publications reported in 1985-2020. The prevalence of Chlamydia was 22.48% in China. In the sampling year subgroup, the prevalence after 2011 was the highest (26.14%). In southern China, the prevalence was 30.97%. By contrast, the prevalence in northern China was only 10.79%. Also the difference was significant (p < 0.05). In the provincial level, Hubei had the highest rate of 36.23%. Boars had a higher prevalence (29.47%). The prevalence of Chlamydia detection in pigs with reproductive disorders (21.86%) was higher than that without reproductive disorders. Among the three age groups, finishing pigs (21.43%) had the highest prevalence. The prevalence in large-scale farmed pigs (28.58%) was the highest in the subgroup of feeding methods. The prevalence in farms was 24.29%, which was the highest in the survey areas. The prevalence in spring was the highest with 40.51%. Other methods had the highest prevalence (39.61%) than enzyme-linked immunosorbent assay (ELISA) and indirect hemagglutination assay. The prevalence of Chlamydia psittaci 18.41% was lower than the prevalence of Chlamydia abortus (41.35%). We also analyzed the impact of different climate factor subgroups (rainfall, temperature, and humidity) on the probability of pigs suffering from the disease. The results showed that Chlamydia was widespread in pigs in China. We suggest that we should strengthen the detection of Chlamydia in the semen of breeding pigs and pigs with reproductive disorders, and reasonably control the environment of large-scale pig farms, so as to reduce further infection of Chlamydia in pigs.

Prevalence of Bovine Viral Diarrhea Virus in Ovine and Caprine Flocks: A Global Systematic Review and Meta-Analysis.

Background: Bovine viral diarrhea virus (BVDV) is the causative agent of bovine viral diarrhea. It can infect cattle, sheep, pigs, and other animals, causing diarrhea, miscarriage, and stillbirth, among other symptoms, and it can result in huge economic losses to animal husbandry. There are reports on BVDV infection rates in sheep and goat herds from all over the world and this meta-analysis aimed to evaluate the prevalence of and risk factors for BVDV in sheep and goats. Results: Using the data of 41,297 sheep and goats in 24 countries/regions to calculate a comprehensive prevalence rate for BVDV. The overall prevalence of BVDV infection in sheep and goats was estimated to be 8.6% (95% CI: 5.2-12.7) by immunological methods and 7.3% (95% CI: 2.7-13.7) by molecular methods. Analysis by national income level revealed that prevalence is higher in middle-income countries than in high-income countries (P < 0.05). The study also compared prevalence rates by species of BVDV, sampling year, and test species, but did not find significant differences. Conclusion: This systematic review and meta-analysis is the first to determine the global prevalence of BVDV in ovine and caprine flocks. The prevalence of BVDV in sheep and goat populations varies from region to region, and the situation is not optimistic in some countries.

Prevalence and Risk Factors of Brucellosis, Chlamydiosis, and Bluetongue Among Sika Deer in Jilin Province in China.

Brucellosis and chlamydiosis are important zoonotic diseases and bluetongue virus (BTV) is an arthropod-borne viral disease of ruminants. They are widely distributed around the world, cause large economic losses, and significant harmful effects on humans. However, epidemiological information relating to transmission from commercial sika deer in China is limited. Therefore, from 2016 to 2017, 458 sika deer blood samples were collected from three cities in Jilin Province in China. The Brucella antigen and specific antibodies to Chlamydia and BTV were examined using RT-PCR, indirect hemagglutination assay, and ELISA, respectively. The prevalence of Brucella was found to be 12.9% (59/458) and the seroprevalence of Chlamydia and BTV was 14.4% (66/458) and 17.0% (78/458), respectively. Seasonality was considered a risk factor for the presence of Brucella or BTV in sika deer and the region was considered a risk factor for Chlamydia infection. These data provides reference values for both further research and disease control.