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Cryptosporidiosis is an extensively contagious zoonotic waterborne disease caused by the genus Cryptosporidium and poses to be a danger to public health. Sheep and goats are an intermediate host of Cryptosporidium. Consequently, a first systematic review and meta-analysis are performed to assess the burden of the infection relative to the Cryptosporidium in sheep and goat flocks in China. Five databases were searched for relevant literature in accordance with the inclusion criteria until January 30, 2020. At last, a total of 33 qualified documents were included. We calculate the overall prevalence of Cryptosporidium (4.9%) in sheep and goats in China with the random-effects model. The prevalence after 2014 (4.6%) was higher than that before or in 2014 (2.8%). The pooled prevalence of Cryptosporidium in sheep and goats from Northern China (12.3%) was significantly higher (p < 0.05) than other regions. The infection rate of modified acid-fast staining (14.3%) was the highest among the detection methods. In age subgroups, the prevalence of Cryptosporidium in sheep and goats in 3 months or before was the highest (20.8%). Goats had a higher infection rate (5.9%) in species. The prevalence of large-scale farms (2.8%) was lower than free-ranging farms (4.4%). The medium quality level (6.4%) was the highest. Besides, geographical factors (such as latitude, longitude, height, precipitation, humidity, mean temperature, etc.) were further analyzed as potential risk factors of Cryptosporidium in sheep and goats. This meta-analysis indicates that the Cryptosporidium infection of Chinese sheep and goat flocks is general. Thus, it is necessary to further monitor the prevalence of Cryptosporidium, and the reasonable preventive strategy should be formulated on the basis of the geographical factors of different regions and the differences in sheep and goats' growth stages to reduce the prevalence of Cryptosporidium in sheep and goats.

Toxoplasmosis is a zoonotic disease caused by Toxoplasma gondii, which is widespread in warm-blooded animals and humans. Currently, many studies regarding T. gondii infection in sheep have been published worldwide. However, there is no meta-analysis of sheep infection in China. In this study, five databases were used to retrieve articles related to T. gondii in China. A total of 59 studies from 1987 to June 30, 2020, have been included. We estimated that the combined prevalence of T. gondii in the selected period was 8.5% (3197/28,099). In the analysis of publication year, the lowest positive rate after 2010 was 7.4% (1883/17,313). Geographically, the highest prevalence of T. gondii in sheep was recorded in Southwest China 19.2% (490/2080). Analysis according to age showed that the prevalence of infection in sheep older than 12 months was significantly (P 0.05) higher than that in younger animals. The prevalence of T. gondii in sheep farmed by farmers was 7.2% (566/6336), which was higher than 5.3% (660/3121) of large-scale farming, suggesting a role for the feeding and husbandry. We also analyzed the impact of different geographic and climatic factors on the prevalence of T. gondii infection in sheep. The results showed that the prevalence was higher in low altitude, warm, humid, and high rainfall areas. We suggest that appropriate control programs should be formulated according to the differences in reproduction patterns and geographical conditions in different regions to reduce the prevalence of T. gondii among sheep in China.

Background Swine coccidiosis, a protozoan disease caused by coccidia, can result in diarrhoea and weight loss in piglets and even economic losses in the pig industry. Here, we report the first systematic review and meta-analysis of the prevalence of coccidia (including Eimeria spp. and Cystoisospora suis) in pigs in China. Methods Five databases (PubMed, ScienceDirect, Chinese Web of Knowledge, Wanfang, and Chongqing VIP) were searched and 50 studies (46,926 domestic pigs, 22 provinces) ultimately identified pertaining to the prevalence of coccidia infection from 1980 to 2019. We incorporated the effect size using the random-effects model in the “meta” package in R software and conducted univariate and multivariate meta-regression analyses using a mixed-effects model. Results The pooled prevalence rate of coccidia in pigs was 21.9%, including the C. suis infection rate of 9.1%. The highest prevalence of coccidia (39.6%) was found in northwest China, and this region also presented the lowest prevalence of C. suis (4.7%). In the subgroup analysis based on sampling year, the highest prevalence of coccidia was detected in 2001 or earlier (32.6%), whereas the lowest rate was found in 2012 or later (14.3%). An opposite trend was observed for C. suis (5.5% in 2000 or earlier vs 14.4% in 2000 or later). The prevalence of coccidia in extensive farming systems (29.5%) was higher than that in intensive farming systems (17.3%). In contrast, the point estimate of C. suis prevalence was lower in the extensive farming systems (5.1%) than in the intensive farming systems (10.0%), but the difference was not significant (P > 0.05). Among the four age categories, the highest total coccidia prevalence (26.2%) was found in finishing pigs, followed by suckling piglets (19.9%), whereas the highest prevalence of C. suis (14.9%) was observed in suckling piglets. Conclusions Our findings suggest that coccidia infection in Chinese pigs is common, although the prevalence of C. suis in pigs does not receive sufficient attention. We recommend the rational use of anticoccidial drugs to avoid drug resistance and the development of preventive and control measures for C. suis to reduce the incidence of swine coccidiosis. Graphical Abstract

Cryptosporidium is an important zoonotic parasite that can infect a variety of hosts, including pigs and humans, through water and food. Many studies on Cryptosporidium infection in pigs have been reported worldwide. However, the meta-analysis of Cryptosporidium infection in pigs in China has not been published. This study retrieved articles related to Cryptosporidium in pigs in China by using four databases: Chinese National Knowledge Infrastructure (CNKI), PubMed, VIP Chinese journal database and Wanfang Data. We retrieved 40 studies related to Cryptosporidium infection in China, and those articles were harvested from the inception to 1 January 2020. We estimated that the overall prevalence of pigs with Cryptosporidium in the selected period was 12.2% (4,349/30,404). In the sampling year subgroup, the prevalence rate after 2010 was the lowest at 8.7% (2,087/18,100). In Northern China, the Cryptosporidium prevalence was 47.9% (34/71). By contrast, the prevalence of Cryptosporidium in Southwestern China was only 6.9% (778/6,445). The infection rate of Cryptosporidium in diarrhoea pigs of 15.6% (74/384) was higher than that in non-diarrhoea pigs at 10.8% (378/2,840). Among the four age groups, the prevalence of weaning pigs of 16.2% (530/3,243) was the highest, and the difference was significant (p < .05). The prevalence of Cryptosporidium in extensive farming was 25.7% (660/3,121), which was significantly higher than in intensive farming 8.7% (566/6,336), and the prevalence of infection was related to the farming modes (p < .05). We also analysed the impact of different geographic factor subgroups (longitude, latitude, precipitation, temperature, humidity, climate and altitude) on the prevalence of pigs. The results showed that cryptosporidiosis was widespread in pigs in China. We suggest that appropriate control schemes should be developed according to the differences in breeding patterns and geographic conditions in different regions, and effective management measures should be developed to reduce the spread between pigs.

Clonorchis sinensis, an important fish-borne zoonotic trematode, is widely distributed in South-East Asia, especially in China. Infections from human and animal reservoir hosts occur due to the consumption of raw or undercooked fish with C. sinensis metacercariae. This study aimed to evaluate the prevalence of C. sinensis metacercariae in fish in South-East Asia via systematic review and meta-analysis. We searched PubMed, ScienceDirect, China National Knowledge Infrastructure, Wanfang and Chongqing VIP databases for studies published between 1976 and 2020 that are related to the prevalence of C. sinensis metacercariae in fish. Studies were screened with keywords based on inclusion and exclusion criteria. Seventy-one eligible articles were identified, covering three countries: China, Korea and Vietnam. The pooled prevalence of C. sinensis metacercariae in fish from South-East Asia was 30.5%, with 35.1% in China, 29.7% in Korea and 8.4% in Vietnam. In subgroup analyses of climate, season, water source and publication date, the highest prevalence was identified in the Dwb climate type (43.3%), summer (70.2%), river (34.5%) and pre-2001 publications (38.9%), respectively. In comparison, the lowest prevalence was found in the Dfa climate type (14.5%), winter (19.5%), lake (8.0%) and post-2001 publications (23.8%). Meta-regression results indicated that country (p = .009), the published time (p = .035) and water source subgroups (p = .003) may be the source of heterogeneity. Overall, our study indicates that a high prevalence of C. sinensis infections occurs in fish in China, Korea and Vietnam, illuminating a significant public health concern in these countries.

Anisakidosis, caused by anisakid larvae, is an important fish-borne zoonosis. This study aimed to summarize the prevalence of anisakid infection in fish in China. A systematic review and meta-analysis were performed using five bibliographic databases (PubMed, CNKI, ScienceDirect, WanFang, and VIP Chinese Journal Databases). A total of 40 articles related to anisakid infection in fish in China were finally included. Anisakid nematodes were prevalent in a wide range of fish species, and the overall pooled prevalence of anisakid nematodes in fish in China was 45.5%. Fresh fish had the highest prevalence rate (58.1%). The highest prevalence rate was observed in Eastern China (55.3%), and fish from East China Sea showed the highest prevalence of anisakid nematodes (76.8%). Subgroup analysis by sampling year suggested that the infection rate was higher during the years 2001–2011 (51.0%) than the other periods. Analysis of study quality revealed that the middle-quality studies reported the highest prevalence (59.9%). Compared with other seasons, winter had the highest prevalence (81.8%). The detection rate of anisakid nematodes in muscle was lower (7.8%, 95% CI: 0.0–37.6) than in other fish organs. Our findings suggested that anisakid infection was still common among fish in China. We recommend avoiding eating raw or undercooked fish. Region, site of infection, fish status and quality level were the main risk factors, and a continuous monitoring of anisakid infection in fish in China is needed.

Cryptosporidiosis is an extensively contagious zoonotic waterborne disease caused by the genus

Bovine rotavirus (BRV) is a potential zoonotic intestinal pathogen that brings a serious threat to calf health, and has resulted in huge economic losses to China's breeding industry. Here, a systematic review and meta-analysis was conducted to estimate the prevalence of BRV among Bovidae from 1984 to 2021 in China. A total of 64 publications on BRV investigation in China were screened from the databases Chinese National Knowledge Infrastructure (CNKI), Wan Fang Database, Technology Periodical Database (VIP), PubMed, and ScienceDirect. The random-effect model was used to calculate the pooled prevalence of BRV, and the analyzed data were derived from 25 provinces in China. The estimated pooled prevalence of BRV in China was 35.7% (8176/17,292). In addition, the prevalence of BRV in Southwestern China (77.1%; 2924/3600) was significantly higher than that in other regions of China. Regarding geographic and climatic factors, the prevalence of BRV in the subgroup of latitude 30-35° (76.8%; 3303/4659) was significantly higher than that in the subgroup of latitude less than 30° (37.0%; 485/1275) or more than 35° (32.6%; 1703/5722), while the prevalence of BRV in the subgroup of longitude 100-105° (75.4%; 2513/3849) was significantly higher than that in the subgroup of longitude less than 100° (32.6%; 619/2255) or more than 105° (48.9%; 2359/5552). Rainfall was positively correlated with the prevalence of BRV, whereas temperature was negatively correlated with the positive rate of BRV (P 0.05). Our data showed that the prevalence of BRV was strongly correlated with geographical and climatic conditions. Thus, we recommend that the corresponding prevention and control programs should be formulated according to different geographical conditions. The strengthening of BRV surveillance in areas with high altitude, low temperature, and heavy rainfall may contribute to the decrease of the incidence of BRV infection among Bovidae herds in China.

Cryptosporidium is the causative agent of cryptosporidiosis. Cryptosporidium not only has a worldwide distribution, but also can infect various hosts, including dairy cattle and humans. Although numerous researches on Cryptosporidium infection in cattle have been conducted, no nationwide study on the prevalence of Cryptosporidium infection in dairy cattle in mainland China was carried out. In this meta-analysis, five databases, including PubMed, ScienceDirect, China National Knowledge Infrastructure (CNKI), Chongqing VIP, and Wanfang, were used to search for published papers regarding Cryptosporidium infection in dairy cattle in China from inception to February 25, 2019. Our study obtained 60 eligibility studies that reported Cryptosporidium infection in dairy cattle. We estimated the pooled Cryptosporidium prevalence to be 17.0% (3,901/33,313), with 16.9% (722/5,191) in Central China, 17.4% (959/6,162) in Eastern China, 29.8% (404/2,021) in Northeastern China, 15.7% (227/2,344) in Northern China, 15.8% (1,042/11,452) in Northwestern China, 9.5% (494/5,758) in Southern China, and 13.7% (53/385) in Southwestern China. The pooled prevalence of Cryptosporidium in before 2000 group (28.0%, 944/3,417) was significantly higher than in 2000–2010 group (11.1%, 384/3,643) and after 2010 group (13.7%, 2,134/22,411). Cattle with the age of ≤ 12 months (22.5%, 2,142/12,948) had a significantly higher prevalence than those of > 12 months (9.5%, 840/10,282). The pooled prevalence of Cryptosporidium in different seasons ranged from 8.2% (343/4,552) in Autumn to 19.5% (285/1,570) in Winter. Diarrhea cattle (38%, 133/477) had a higher Cryptosporidium prevalence than non-diarrhea cattle (13.0%, 367/2423). The pooled prevalence of Cryptosporidium in different provinces was various, with the highest (35.6%, 355/1,667) in Heilongjiang province, and the lowest (4.3%, 15/440) in Tianjin province. The univariate meta-regression analyses indicated that the collection year (P = 0.002) and age of cattle (P = 0.001) might be sources of heterogeneity. This systematic review suggests that China is a country where cryptosporidiosis frequently occurs in cattle. Due to the particular relationship between dairy cattle and feeder, further research is required to investigate the links between cattle ownership and Cryptosporidium infection.

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 i...

Background: Bluetongue caused by the bluetongue virus (BTV) is a non-contagious and an insect-borne disease mainly affecting domestic and wild ruminants. Bluetongue in cattle is associated with vesicular lesions, weight loss, low milk production, and low reproductive capacity. It should not be ignored as it is associated with large economic losses to the livestock breeding industry in China. Although many studies have investigated bluetongue virus infection in cattle, no nationwide study on the prevalence of bluetongue virus infection in cattle from China has yet been conducted. This meta-analysis aimed to evaluate the seroprevalence and risk factors for bluetongue in cattle.Results: We collected 50 publications from 1988 to 2019 through PubMed, ScienceDirect, Chinese Web of Knowledge (CNKI), VIP Chinese journal database, and Wanfang database. A total of the pooled bluetongue seroprevalence of 12.2% (5,332/87,472) in cattle was tested. The point estimate of bluetongue collected from 2001 to 2011 was 22.5% (95% CI: 1.2–58.9), which was higher than after 2012 (9.9%, 95% CI: 3.3–19.4). The analysis of the feeding model subgroup revealed that the seroprevalence of bluetongue was significantly higher (P < 0.05) among free-range cattle (22.5%; 95% CI: 7.7–42.3) than among cattle from intensive farming systems (1.8%; 95% CI: 0.0–6.7). The seroprevalence of bluetongue in different species showed significant variation (P < 0.05), with the highest seroprevalence of 39.8% (95% CI: 18.7–63.0) in buffalo and the lowest seroprevalence of 4.3% (95% CI: 1.2–9.0) in yak. In the zoogeographical division subgroup, the seroprevalence of bluetongue correlated positively within a certain range with the species distribution of Culicoides.Conclusion: Our findings suggested that bluetongue was prevalent in cattle in China. In addition, the contact with sheep, other ruminants, or transmission media such as Culicoides may increase the seroprevalence of bluetongue disease in cattle. It is necessary to carry out continuous monitoring of the bluetongue seroprevalence. Moreover, comprehensive and improved strategies and measures should be implemented to prevent and control the spread of bluetongue.

Toxoplasma gondii is an important intracellular parasitic protozoan with a variety of hosts, including chickens, which poses a potential threat to public health. However, little is known regarding overall T. gondii infection in chickens in China. Herein, the prevalence and risk factors associated with T. gondii infection in chickens in China were investigated using a meta-analysis. Forty studies regarding the prevalence of T. gondii in chickens in China from 1993 to 2021 were identified using five databases (PubMed, Science Direct, CNKI, Wang Fang, and VIP). Quantitative and potential sources were analyzed through subgroup analysis and meta-regression in R v3.5.2. The overall prevalence of T. gondii in chickens in China was 13.4% (95% confidence interval (CI): 10.9-16.0). In the region subgroup, the lowest prevalence was presented in Northwestern China (6.0%, 95% CI: 3.2-9.5; P 0.001). Seasonally, T. gondii prevalence was the highest in spring (17.9%, 95% CI: 7.7-30.9; P = 0.007). Among detection methods, the prevalence in the ELISA subgroup was the highest (22.8%, 95% CI: 17.1-29.1; P 0.001). According to the farming mode, the prevalence of T. gondii in free-range chickens (19.5%, 95% CI: 15.4-23.9) was significantly higher than that in chickens raised by intensive farming (7.4%, 95% CI: 5.1-10.2; P 0.001). We also estimated the relationships between region, sampling year, chicken age, chicken application, gender, sample classification, study quality, and T. gondii prevalence in chickens in China. Our study showed that region, season, and farming model played important roles in T. gondii infection of chickens. Integrated control measures should be undertaken to reduce the losses caused by T. gondii infection to the chicken industry.

Hepatitis E virus (HEV) is a zoonotic pathogen that has spread worldwide. The HEV reservoir associated with livestock hepatitis E poses a huge threat to public health. Awareness of the prevalence and spatial distribution of livestock hepatitis E is valuable to prevent and control diseases caused by HEV, especially human hepatitis E infection. Currently, swine, including pigs (Sus scrofa), are recognized as the major reservoir of HEV. Therefore, we conducted a systematic review and meta-analysis to evaluate the pooled prevalence of HEV among swine in China. A total of 71 published papers on HEV infection in swine in China (including data from 49,523 animals) from January 1, 2010 to December 31, 2019 met the standard after searching five databases including the Technology Periodical Database, the Wan Fang Database, the China National Knowledge Infrastructure, PubMed, and ScienceDirect. A random effects model was used to calculate the pooled prevalence of HEV in swine. The results showed that the seroprevalence was 48.0% (95% confidence interval (CI) 39.6–56.9) and the prevalence of HEV RNA was 14.4% (95% CI 10.7–18.5). The estimated overall prevalence was 34.1% (95% CI 27.2–41.4). Central China (68.0%, 95% CI 42.2–89.1) had a significantly higher prevalence than other regions. In the publication year subgroup, the prevalence in 2016 or later (27.2%, 95% CI 19.3–36.0) was significantly lower than that in 2011 or earlier (49.0%, 95% CI 36.2–61.8). The prevalence of IgG (42.9%, 95% CI 31.7–54.6) was significantly higher than that of IgM (4.9%, 95% CI 1.6–9.7). Suckling piglets (15.6%, 95% CI 6.6–27.1) had a lower prevalence compared with that in other age groups. In all sample types, body fluids showed the highest prevalence (50.5%, 95% CI 41.7–59.3). Moreover, the pooled prevalence of HEV in boars was higher than that in sows (35.4% > 17.3%). The analysis suggested that HEV infection is common among swine in China. Further strengthening HEV testing in boars, controlling environmental pollution, and reducing the mixed feeding of different stages could contribute to reducing HEV infection in pigs in China and the risk of porcine HEV infection in humans.

Toxoplasma gondii is a widely distributed protozoan parasite that can infect a variety of warm-blooded animals including humans and goats. This is the first meta-analysis to assess the overall seroprevalence and potential risk factors of T. gondii infection among goats in China. Databases including the VIP Chinese Journal Databases (VIP), the China National Knowledge Infrastructure (CNKI) database, WanFang, ScienceDirect, and PubMed were searched comprehensively for relevant studies published from 2010 to date. A random-effects model was used to calculate pooled seroprevalence estimates with 95 % confidence intervals (CI) and data were analyzed from 13 provinces in China. The pooled T. gondii seroprevalence in goats was estimated as 9.9 %. Goats T. gondii had the highest seroprevalence in Southwestern China (13.3 %) and the lowest in Northeastern China (7.3 %). The seroprevalence in the sub-group before 2012 (8.0 %) was lower than that in 2012-2015 (15.2 %) and 2016 or later (9.2 %). Goats aged > 12-months had a higher seroprevalence (11.7 %) than ≤ 12-months (10.7 %). The seroprevalence in female goats was 12.5 % and 12.2 % in male goats. In season subgroups, the seroprevalence was lowest in autumn (6.1 %). Naturally grazed goats had a seroprevalence of 8.1 % of infection and 7.8 % in intensively fed goats. We also evaluated the effects of geographical and climate variables on the pooled seroprevalence of T. gondii in goats in China. The results indicated that toxoplasmosis is widely distributed in goats in China. In the context of ensuring animal welfare, we suggest the continued promotion of the transition from natural grazing to intensive agriculture to strengthen disease prevention. Prevention would be better carried out in areas suitable for the survival and reproduction of T. gondii. Breeders need to regularly disinfect the feeding areas and pens or other areas of goat activity thoroughly to reduce the impact of environmental factors responses on the infection of goats to T. gondii.

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.

Protists of the Blastocystis genus are distributed worldwide and can infect a range of hosts. However, data concerning Blastocystis infection are limited for sika deer and are not available for black bears. Therefore, in the present study, a total of 312 black bears (Ursus thibetanus) from Heilongjiang Province and 760 sika deer (Cervus nippon) from four different northern Chinese provinces were investigated. Blastocystis infection in these animals was detected via PCR amplification of the small subunit rRNA gene in fecal samples. The prevalence of Blastocystis infection in black bears and sika deer was 14.4% (45/312 positive samples) and 0.8% (6/760 positive samples), respectively. Young black bears (18.3%) had a significantly higher Blastocystis prevalence than adult bears (9.1%). The prevalence of Blastocystis was significantly higher in black bears raised outdoors (24.6%) than in bears raised indoors (12.2%). Blastocystis-positive sika deer were only found in Jilin Province (1.3%, 6/480). Female sika deer (0%, 0/61) had a significantly lower Blastocystis prevalence than males (0.9%, 6/699). Sanger sequencing was used to determine the small subunit rRNA gene sequences of the Blastocystis-positive PCR products. A neighbor-joining phylogenetic tree based on the small subunit rRNA gene sequences showed that only Blastocystis subtype (ST)1 was identified in black bears, whereas ST10 and ST14 were found in sika deer. This is the first report of Blastocystis ST1 infection in black bears. These findings also extend the distribution information of Blastocystis subtypes, which will provide a foundation for further study of Blastocystis in different hosts in China.

Porcine circovirus type 2 (PCV2) causes infectious diseases in pigs leading to considerable economic losses in the pig industry. To prevent and control PCV2 infections, is important to understand the prevalence and geographical distribution of the virus. We performed the first systematic review and meta-analysis to estimate the prevalence of PCV2 in China. From PubMed, ScienceDirect, Chinese Web of Knowledge, Wanfang, and VIP Chinese Journal, we extracted 53 studies published in China between 2015 and 2019. There were 29,051 samples, 14,230 of which were positive for PCV2. The pooled prevalence of PCV2 was 46.0%, with the highest in Northeastern China (58.1%). The highest prevalence was 86.3% in Xinjiang province. Nursery pigs had the highest prevalence of PCV2 (50.9%), and the serological test detected the highest number of cases (58.5%). PCV2 prevalence was 50.1% in intensive farms and 37.5% in extensive farms. Our findings showed that PCV2 is common throughout China. Effective control measures are necessary to reduce PCV2 infections.

In the Qinghai-Tibet Plateau of China, the yak is an animal of particular economic interest, which provides protein and income for herders in daily life. Brucellosis is a bacterial disease that can infect humans and animals, including yaks. It can damage the yak reproductive system, causing miscarriage and orchitis. At the same time, brucellosis threatens the health of herders. We performed this meta-analysis using R software to explore the combined prevalence and risk factors of brucellosis in yak in China. Variability was assessed by the I2 statistic and Cochran Q statistic. We identified 52 publications of related research from four databases (Wanfang Data, VIP Chinese Journal Database, China National Knowledge Infrastructure, and of PubMed). The pooled prevalence of yak brucellosis was 8.39 %. Prevalence was highest in Southwestern China (11.1 %). The point estimate of brucellosis in yak from 2012 to 2016 was the highest (11.47 %). The point estimate of age ≤ 12 months (1.44 %) was lower than that of age > 12 months (15.6 %). This study shows that yak brucellosis is serious, and its incidence is higher than before 2012. We recommend carrying out large-scale yak brucellosis investigations in Western China and conducting comprehensive testing planning. The detection of brucellosis in adult animals should be strengthened to reduce the economic loss caused by brucellosis to herders and to improve public health.

Interleukin-4 (IL-4), an immunomodulatory cytokine derived from activated T lymphocytes were shown to regulate Th2-type immune responses. It plays an important role in anti-parasitic infections. In this study, a recombinant plasmid was designed using murine IL-4 co-expressed with pgsA anchor system of Lactobacillus plantarum NC8 and was delivered by live Lactobacillus plantarum NC8, which exhibited an enhanced immunogenicity in protection of BALB/c mice from infection with Trichinella spiralis. The results showed that the levels of serum IgG1 and mucosal secretory IgA (sIgA) were both increased significantly in mice orally inoculated with NC8-pSIP409-pgsA-mIL-4, and the Th2 phenotype immune response was up-regulated. A 29.9 % reduction in adult worm burden at 7 days post-infection (dpi) and 83.3 % reduction in muscle larvae burden at 28 dpi were observed in immune-stimulated mice with NC8-pSIP409-pgsA-mIL-4. Moreover, weight loss and pathological changes were also improved in mice of NC8-pSIP409-pgsA-mIL-4 group. Taken together, it suggests that NC8-pSIP409-pgsA-mIL-4 could improve the intestinal mucosal immunity and promoted the elimination of the adult worm in Trichinella-infected mice. This study laid the foundation for the development of a novel vaccines against Trichinellosis.

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.

Background Bovine tuberculosis (bTB), caused by members of the Mycobacterium tuberculosis complex bacteria, mainly Mycobacterium bovis (M. bovis), is a major threat to public health and economic development. There has been no systematic epidemiological assessment concerning bTB in dairy cattle in China. Methodology/principal findings Literature related to bTB in China was retrieved from China National Knowledge Infrastructure (CNKI), PubMed, ScienceDirect, VIP Chinese Journals Database, and Wan Fang Database to build the first meta-analysis for estimating the prevalence and infection moderators of bTB in dairy cattle in China. A total of 100 relevant studies published from 2010 to 2019 were included. We estimated the overall prevalence of bTB was 2.4% (95% CI: 2.1–2.8) during this decade. In the sampling year subgroup, the prevalence was lowest in 2017 or later at 0.8% (95% CI: 0.3–1.5). The lowest prevalence was 0.7% (95% CI: 0.5–1.0) in Northwestern China. The lowest prevalence was 2.1% (95% CI: 1.8–2.5) using SIT test. Heifer cows had the highest prevalence, which was 27.1% (95% CI: 9.7–49.2). The prevalence in scale farming was 3.7% (95% CI: 3.1–4.3), significantly higher than that in free-range farming (1.7%, 95% CI: 1.1–2.4). The prevalence of bTB was highest in summer at 4.0% (95% CI: 1.7–7.0). In addition, the influence of different geographical factors (altitude, longitude, latitude, precipitation, temperature, humidity) on the prevalence was analyzed. Conclusions/significance The results showed that bTB was widespread in China but has been gradually reduced through concerted national intervention. It is suggested that different countries should formulate corresponding prevention and control measures according to the epidemic situation in its cattle industry. Enhanced monitoring of warm and humid areas may play an important role in reducing the incidence of bTB. In addition, when large-scale breeding is promoted, attention should be paid to standardizing breeding management and improving animal welfare to reduce the prevalence of bTB in cattle., Author summary bTB is a neglected zoonotic disease caused by members of the Mycobacterium tuberculosis complex bacteria (M. bovis, mainly), which is also called “TB disease from bovine sources” when it occurs in humans. It is still widespread in China although the prevalence has gradually reduced through national intervention. Because beef and dairy products are important human dietary sources of protein, bTB has a great impact on public health and safety. We constructed the first meta-analysis to assess the epidemic of bTB in dairy cattle in China over the past 10 years and analyzed the potential moderators of bTB. A total of 100 studies were included. The results showed that bTB was common and unevenly distributed in China. The potential moderators affecting the bTB epidemic were region, sampling year, detection methods, age of dairy cattle, feeding mode, season, and certain geographical and climatic factors (longitude, precipitation, mean temperature, humidity, and altitude). These important findings may help in the formulation of policies to control the prevalence of bTB in cattle, thereby reducing the economic losses caused by bTB and reducing the threat of bTB to human health.

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., Author summary Echinococcosis is a neglected zoonotic disease caused by the larval form of Echinococcus spp. tapeworms. It is prevalent in parts of China although unevenly distributed. The dog is one of the terminal hosts of Echinococcus spp., which is key in controlling the epidemic of canine echinococcosis. We constructed the first meta-analysis to assess the epidemic of Echinococcus in dogs in China over the past 10 years, and analyzed potential risk factors. We analyzed 108 studies of Echinococcus in dogs in China and evaluated the infection status and potential risk factors. The influential factors included province, geographical and climatic factors, publication year, sampling district category, detection methods, dog classification, medication, and the quality level of included studies. These important findings explain the differences in prevalence of canine echinococcosis in parts of China, and help to prevent the disease and reduce the risk to the public.

Toxoplasma gondii is one of the most successful intracellular protozoan parasites in the world, which can infect most warm-blooded animals including foxes in the world and cause toxoplasmosis. This is the first meta-analysis to assess the overall prevalence and potential risk factors of T. gondii among foxes in the world. Relevant studies were comprehensively collected from ScienceDirect, Springer-Link, PubMed, VIP Chinese Journal Databases (VIP), WanFang, and China National Knowledge Infrastructure (CNKI) databases. The random-effect model was used to calculate pooled prevalence with 95% confidence intervals (CI) and analyzed data were from 20 countries. The pooled T. gondii prevalence in foxes was estimated to be 39.6%. T. gondii has the highest prevalence in North America (51.2%), and lowest in Asia (8.3%). The prevalence in the sub-group after 2006 (44.7%) was lower than 2006 or before (48.5%). The prevalence in female foxes was 46.1%, which was higher than that in male foxes (19.7%). In species subgroup, red fox has the highest prevalence (46.8%). Wild foxes have a higher rate of infection (40.8%) than captive foxes (8.4%). Genotype Ⅱ of T. gondii is the most prevalent in foxes. We also evaluated the effects of geographical and climate variables on pooled prevalence of T. gondii in foxes. Our research indicated that toxoplasmosis widely existed in the world. The investigation of T. gondii infection in wild animals can provide an estimate of environmental pollution and T. gondii circulation in the ecosystem. It is essential for us to prevent and control T. gondii infection in foxes in order to reduce the risk of human infection.

Toxoplasma gondii can infect almost all warm-blooded animals, including cattle, causing serious disease to animals and humans. Because cattle provide milk and meat for humans, an increasing number of people are raising cattle as a source of income. However, T. gondii may be transmitted to humans through the meat and milk of cattle. Although substantial relevant studies have been performed, overall data on the seroprevalence of T. gondii in cattle is still lacking. In this meta-analysis, 71 relevant studies were included from five databases that investigated the seroprevalence of T. gondii in cattle in China from 2010 to 2019. The overall pooled T. gondii seroprevalence in cattle was 10.1% (4217/39,274) in China. The seroprevalence of T. gondii was highest in southwestern China (21.6%, 727/3117) and lowest in northern China (4.5%, 185/1966). Due to the implementation of disease control measures during 2012 to 2020, the lowest positive rate was seen in the post-2017 subgroup of sampling years (5.8%, 170/3022). In the cattle breeds subgroups, the seroprevalence was highest in yaks (14.3%, 1695/10,777). Cattle aged ≥12 months (9.6%, 1248/12,438) had a higher seroprevalence than those

Haemophilus parasuis, a gram-negative bacterium as an early commensal colonizer in the upper respiratory tract of weaning pigs (Sus scrofa), is one of the most important bacterial pathogens affecting pig populations. It is the causative agent of Glasser’s disease, causing systemic infection and polyserositis, meningitis, and arthritis. H. parasuis infection can result in high mortality and morbidity with, the significant economic losses for pig producers. To estimate the overall disease prevalence of H. parasuis in pigs from China, we performed a meta-analysis using five bibliographical databases: PubMed, ScienceDirect, CNKI, Wanfang, and VIP Chinese Journal Databases. A total of 41 articles published between 2005 and 2019, fulfilled the final inclusion criteria. The overall prevalence of H. parasuis in pigs in China was 27.8 % with the highest prevalence between 2011 and 2015 (41.0 %). In terms of pig age, the point estimate of H. parasuis prevalence was higher in suckling piglets (29.2 %) compared with that for other pig ages. The prevalence in the serum subgroup (29.8 %) was higher than that in the nasal swab subgroup (12.5 %). The results of the present meta-analysis showed that H. parasuis infection was common in pig populations in China; therefore, effective control measures are necessary to reduce this threat to pig populations.

Toxoplasma gondii infecting virtually all warm-blooded animals, including humans, is an intracellular protozoan parasite. The immunocompromised patients or pregnant women infected by Toxoplasma usually can cause encephalitis or abortion. Deer are also the important intermediate host of the parasite and people can be infected by ingesting the undercooked venison. Therefore, to raise the attention of the researchers and T. gondii infection on people in deer, we conducted the meta-analysis. All potential publications on the T. gondii infection in deer were retrieved by searching the PubMed, ScienceDirect, Springer- Link, China National Knowledge Infrastructure (CNKI), WanFang, and VIP Chinese Journal Databases. Finally, a total of 48 publications were included. The pooled seroprevalence of T. gondii infection in deer was 22.92% (95% CI 17.89-28.38) calculated by the random effect model. The seroprevalence of T. gondii infection in deer was the lowest in Asia (12.72%, 95% CI 6.29-20.89), and the highest in North America (32.21%, 95% CI 20.32-45.39). The highest point estimate of deer T. gondii in detection method subgroup was using MAT (31.28%, 95% CI 20.15-43.61). The estimated pooled seroprevalence of T. gondii infection in elk (63.50%, 95% CI 50.01-76.01) was higher than other types of deer. Our meta-regression analysis found that the subgroups including region, sampling year, age, climate, and deer species may be the main heterogeneous source in our meta-analysis. It is necessary to monitor the seroprevalence of T. gondii infection in deer at all times. Furthermore, people should be taken to precautions when ingesting the venison by cooking it well before serving to prevent the T. gondii infection via eating venison.

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.

Research on cysticercosis has been stimulated by the rapid development of genomics, proteomics and bioinformatics and the emergence of molecular biological and immunological technologies. In this review, we attempt to discuss the research development on genomics of Taenia solium and candidate vaccines and antigens for cysticercosis. This will provide a new perspective for studying genomics of Taenia solium and for cysticercosis prevention and treatment, and provide a wealth of informative data for the development of novel and highly efficient vaccines against cysticercosis or diagnostic antigen molecules for cysticercosis.

Toxoplasmosis, one of the most common zoonoses worldwide, is caused by Toxoplasma gondii. T. gondii can infect almost all warm-blooded animals, including humans. Horses are an intermediate host of T. gondii, representing a potential risk for humans. To determine the T. gondii seroprevalence in horses worldwide, a global meta-analysis was conducted. A total of 35 publications were obtained by searching the PubMed, ScienceDirect, Chinese Web of knowledge (CNKI) and Wanfang databases. A total of 12,354 horses were assessed, of which 1580 were positive for T. gondii. The pooled overall seroprevalence of horses infected by T. gondii was 11.29%. No significant difference of T. gondii seroprevalence was observed between male and female horses. The seroprevalence of T. gondii in horses from different countries varied. Our findings suggest that toxoplasmosis is prevalent in horses worldwide. Therefore, it is necessary to implement continuous monitoring of the status of T. gondii seroprevalence in horses. Moreover, powerful regulatory measures should be implemented to prevent and control the spread of toxoplasmosis.

Recently, poly-γ-glutamic acid synthetase A (pgsA) has been applied to display exogenous proteins on the surface of Lactobacillus casei or Lactococcus lactis, which results in a surfacedisplayed component of bacteria. However, the ability of carrying genes encoded by plasmids and the expression efficiency of recombinant bacteria can be somewhat affected by the longer gene length of pgsA (1,143 bp); therefore, a truncated gene, pgsA, was generated based on the characteristics of pgsA by computational analysis. Using murine IL-10 as an exogenous gene, recombinant Lactobacillus plantarum was constructed and the capacity of the surface-displayed protein and functional differences between exogenous proteins expressed by these strains were evaluated. Surface expression of IL-10 on both recombinant bacteria with anchorins and the higher expression levels in L. plantarum-pgsA'-IL-10 were confirmed by western blot assay. Most importantly, up-regulation of IL-1β, IL-6, TNF-α, IFN-γ, and the nuclear transcription factor NF-κB p65 in RAW264.7 cells after stimulation with Poly(I:C) or LPS was exacerbated after co-culture with L. plantarum-pgsA. By contrast, IL-10 expressed by these recombinant strains could reduce these factors, and the expression of these factors was associated with recombinant strains that expressed anchorin (especially in L. plantarum-pgsA'-IL-10) and was significantly lower compared with the anchorin-free strains. These findings indicated that exogenous proteins could be successfully displayed on the surface of L. plantarum by pgsA or pgsA', and the expression of recombinant bacteria with pgsA' was superior compared with bacteria with pgsA.