Meta-Analysis of the Prevalence of Echinococcus in Sheep in China From 1983 to 2020

Whole-genomic comparison reveals complex population dynamics and parasitic adaptation of Echinococcus granulosus sensu stricto

Cystic echinococcosis (CE), caused by Echinococcus granulosus sensu stricto (s.s.), poses a substantial risk to both humans and domestic animals globally. Here, we compared the whole genomes of 111 E. granulosus s.s. samples from China. Genomic variation data revealed frequent cross-fertilization in the hermaphroditic E. granulosus. The G1 and G3 genotypes represent distinct mitochondrial lineages, while showing no differentiation in the nuclear genome, suggesting mito-nuclear discordance caused by historical geographic separation and subsequent fusion. Population structure, demographic history, and gene flow among populations reflected the transmission route of E. granulosus s.s. from the Middle East to Qinghai-Xizang Plateau through the migration of nomadic people, followed by introgression during secondary contact. Genomic variations highlighted selection signatures within the genome prone to balancing selection, particularly impacting genes encoding membrane-related proteins, representing a potential evolutionary strategy for adaptation to parasitic life. Balancing selection pressure on the gene-coding sodium/bile acid cotransporter led to its high level of genetic stability, which may play a crucial role in the survival and development of E. granulosus during the parasitic stage, making it a potential drug target for the treatment of CE. Meanwhile, other genomic regions under strong balancing selection may provide potential targets for protective immunity. These findings offer valuable insights into the complex dynamics and adaptive evolution of E. granulosus s.s. in China.IMPORTANCEEchinococcus granulosus sensu stricto (s.s.) is the primary cause of cystic echinococcosis (CE), a parasitic disease affecting humans and livestock with significant health and economic impacts. Previous studies on this parasite relied on mitochondrial DNA to classify its genotypes and understand its genetic diversity. However, these studies cannot capture the full complexity of its evolutionary dynamics and adaptation strategies. Our research employs comprehensive genome-wide sequencing, offering a more nuanced view of its genetic landscape. We discovered that cross-fertilization appears to be a prevalent reproductive strategy in the hermaphroditic E. granulosus, underpinning the observed deep mitochondrial divergence between genotypes G1 and G3, as well as gene flow among populations. The transmission history of E. granulosus s.s. in China and its widespread genetic mixing were likely facilitated by the migrations of nomadic peoples. Furthermore, we identified genes under balancing selection, including the gene involved in the uptake of host bile acids, which play a crucial role in the parasite's survival and development, potentially offering new targets for intervention. Our research advances the understanding of the genetic diversity and evolutionary strategies of E. granulosus, laying the foundation for improved control measures of CE.

Echinococcus Infection and Metacestode Fertility in Yaks and Sheep - Four Provincial-Level Administrative Divisions, Northwestern China, 2023

What is already known about this topic?

Echinococcosis is a parasitic zoonosis caused by the larval stage of cestode species belonging to the genus Echinococcus, which is highly prevalent in northwestern China. Echinococcus spp. includes numerous species/genotypes that have different infectivity and parasitism patterns in livestock hosts, potentially affecting the transmission dynamics of the parasite.

What is added by this report?

In four PLADs of China, the prevalence of Echinococcus was 16.5% in yaks and 9.41% in sheep. The predominant species/genotype was E. granulosus s.s. (G1/G3), which mainly infected sheep liver and yak lung. However, fertile cysts were more frequent in sheep than in yaks.

What are the implications for public health practice?

Understanding the livestock infection rate, prevalent species/genotypes, and cyst fertility is essential for elucidating the mechanisms of Echinococcus transmission and pathogenesis. This knowledge lays the foundation for developing accurate prevention and control strategies.

Quantifying the impact of recent disease outbreak of zoonotic nature in small-scale dairy farmers in Wayanad, Kerala, India

The recent outbreaks of zoonotic nature have resulted in a rigours impact on the economies of many countries. The livestock sector is one of the major sub-sector in Indian agriculture. As a by-product of the lockdown imposed by the government due to the emergence of recent zoonosis (COVID- 19), dairy farmers have faced many issues with the sales of milk, availability of fodder etc. A cross-sectional study was carried out using a well-structured questionnaire circulated among the participants (n = 382) to understand the socioeconomic conditions and the costs and expenses incurred by the farmers using the Total Cost (TC) - Total Revenue (TR) approach to estimate economic loss incurred by dairy farmers in Wayanad District, Kerala. Economic loss was subsequently determined by comparing the total costs incurred by the farmers with their total revenue. Most of the farmers were female and every respondent belonged to socio-economic group of INR.8763 and above per month. A total loss of USD 109.6 was estimated per farmer, with TC accounting for USD 390.39 and TR accounting for USD 280.79, indicating that farmers are affected during the pandemic-imposed lockdown, similarly the pandemic-induced loss and farming experiences explained very less variation (R2 = 0.02) and these variables were not associated (p = 0.349) with one another in the study area. This study provides an empirical outlook on loss of dairy farmers, advocates need for educating farmers on fodder management and disease preparedness in the district and pave further research to understand more dimensions and loss using the same framework.

Prevalence of Cystic Echinococcosis in Sheep and Goats of Ethiopia: A Systematic Review and Meta-Analysis

Cystic echinococcosis (CE) is a cestode infection of significant public health and economic importance. A systematic review and meta-analysis was performed to estimate the pooled prevalence of small ruminant CE and associated risk factors in Ethiopia. The published literature written in English from 01 January 2000 to 30 December 2019 was searched from electronic databases and eligible reports that fulfilled inclusion and exclusion criteria. A total of 1140 records were identified, of which 23 reports met the eligibility criteria. A random-effects meta-analysis model was used to pool the prevalence estimations, and a subgroup meta-analysis was utilized to compare the pooled prevalence of CE among the species, age group and sex of the studied animals. The pooled estimated small ruminant CE prevalence was 20.5% (95% confidence interval [CI]: 18.7, 22.3) in Ethiopia, and there was significant heterogeneity among the studies (p < 0.05). The pooled prevalence was higher for sheep, 24.3% (18.5, 30.1), compared to goats, 18.5% (14.5, 22.6), and in adults than young animals. The results of the present analysis suggested a high prevalence of CE at the national level. CE has a significant economic impact due to organ condemnation and production losses and poses a serious public health risk. Effective control requires public awareness, improved slaughterhouse practices, stray dog population management and integrated surveillance and control programmes involving veterinary, public health and environmental sectors. Such synthesis reports are believed to be useful in influencing policymakers towards designing effective prevention and control policies and strategies.

Epitope screening and vaccine molecule design of PRRSV GP3 and GP5 protein based on immunoinformatics

Porcine reproductive and respiratory syndrome (PRRS) is a respiratory disease in pigs that causes severe economic losses. Currently, live PRRSV vaccines are commonly used but fail to prevent PRRS outbreaks and reinfection. Inactivated PRRSV vaccines have poor immunogenicity, making PRRSV a significant threat to swine health globally. Therefore, there is an urgent need to develop an effective PRRSV vaccine. This study used immunoinformatics to predict, screen, design and construct a candidate vaccine that fused B-cell epitopes, CTL- and HTL-dominant protective epitopes of PRRSV strain's GP3 and GP5 proteins. The study identified 12 B-cell epitopes, 6 CTL epitopes and 5 HTL epitopes of GP3 and GP5 proteins. The candidate vaccine was constructed with 50S ribosomal protein L7/L1 molecular adjuvant, which has antigenicity, solubility, stability, non-allergenicity and a high affinity for its target receptor, TLR-3. The C-ImmSim immunostimulation results showed significant increases in cellular and humoral responses (B cells and T cells) and production of TGF-β, IL-2, IL-10, IFN-γ and IL-12. The constructed vaccine was stable and immunogenic, and it can effectively induce strong T-cell and B-cell immune responses against PRRSV. Therefore, it is a promising candidate vaccine for controlling and preventing PRRSV outbreaks.

Prevalence of paratuberculosis in cattle in China: A systematic review and meta-analysis

Bovine paratuberculosis is a chronic infectious disease caused by Mycobacterium avium subspecies paratuberculosis (MAP). Here, a systematic literature review was conducted to investigate the bovine paratuberculosis distribution and associated risk factors in China before 2022. The databases CNKI, VIP, WanFang, PubMed, and ScienceDirect were used to search for articles. The random effect model of the "Meta" package of "R" software was used, and the Arcsine transformation was chosen for the rate conversion analysis. To reveal the factors that led to research heterogeneity, the research data were used for subgroup analysis and univariate meta-regression analysis. Among the 1238 identified articles, 54 met the eligibility criteria. Based on data obtained from the selected articles, the combined positive rate of bovine paratuberculosis was 6.95% in China. In the sampling year subgroup, the positive rate of bovine paratuberculosis before 2013 was 4.94%, which was lower than in other time periods. In the sampling season subgroup, the highest positive rate of bovine paratuberculosis in cattle was 14.60% in the autumn. Furthermore, in the detection method subgroup, the highest positive rate of bovine paratuberculosis was 7.21%, which was detected by using ELISA. In the age subgroup, the positive rate of bovine paratuberculosis was 17.47% in cattle > 12 months old, significantly higher than other age subgroups. The highest positive rate of bovine paratuberculosis was 11.35% for female cattle in the gender subgroup, while in the geographic region subgroup, the highest positive rate was 8.12% for East China, which was significantly higher than in other regions. The highest positive rate of bovine paratuberculosis was for dairy cattle (8.00%), and the highest positive rate by rearing method was 11.03% for non-scale farming. The effects of different geographical and climatic factors on the positive rate of bovine paratuberculosis were evaluated. In summary, we recommend focusing on screening cattle infected with MAP in warm and humid areas.

Modeling and analysis of the transmission dynamics of cystic echinococcosis: Effects of increasing the number of sheep

A transmission dynamics model with the logistic growth of cystic echinococcus in sheep was formulated and analyzed. The basic reproduction number was derived and the results showed that the global dynamical behaviors were determined by its value. The disease-free equilibrium is globally asymptotically stable when the value of the basic reproduction number is less than one; otherwise, there exists a unique endemic equilibrium and it is globally asymptotically stable. Sensitivity analysis and uncertainty analysis of the basic reproduction number were also performed to screen the important factors that influence the spread of cystic echinococcosis. Contour plots of the basic reproduction number versus these important factors are presented, too. The results showed that the higher the deworming rate of dogs, the lower the prevalence of echinococcosis in sheep and dogs. Similarly, the higher the slaughter rate of sheep, the lower the prevalence of echinococcosis in sheep and dogs. It also showed that the spread of echinococcosis has a close relationship with the maximum environmental capacity of sheep, and that they have a remarkable negative correlation. This reminds us that the risk of cystic echinococcosis may be underestimated if we ignore the increasing number of sheep in reality.

Attitude and awareness of Algerian university students about cystic echinococcosis: A cross-sectional study

Cystic echinococcosis is a neglected tropical parasitic disease affecting both humans and animals with considerable socioeconomic impact on affected pastoral and poor communities. CE is endemic in the Mediterranean basin, including Algeria posing a real threat for either animal and public health. This study was conducted to evaluate the level of awareness and knowledge of Algerian university students about this disease and to describe their attitude toward some risky practices. Results showed that despite that a high number of students (76.1%) have heard about CE, their level of knowledge is however medium (63.3%) especially among students of non medical and life sciences specialties. The gaps of knowledge concerns especially the life cycle of the parasite even they are aware about the association of dogs (43.7%) and sheep (59.4%) and considered that dogs are the main source of contamination of humans (58.1%) through contaminated foods (45%) or direct contact with their faeces (44.5%). Regarding their practice, a good level was shown since washing vegetables (99.2%) and washing hands after touching a dog (97.9%) and dogs deworming (82%) were common. These results highlight the need to improve knowledge about the transmission cycle of the parasite through awareness campaign targeting students which could be helpful in CE eradication.

Update on the genetic diversity and population structure of Echinococcus granulosus in Gansu Province, Tibet Autonomous Region, and Xinjiang Uygur Autonomous Region, Western China, inferred from mitochondrial cox1, nad1, and nad5 sequences

The identification of additional Echinococcus granulosus sensu lato (s.l.) complex species/genotypes in recent years raises the possibility that there might be more variation among this species in China than is currently understood. The aim of this study was to explore intra- and inter-species variation and population structure of Echinococcus species isolated from sheep in three areas of Western China. Of the isolates, 317, 322, and 326 were successfully amplified and sequenced for cox1, nad1, and nad5 genes, respectively. BLAST analysis revealed that the majority of the isolates were E. granulosus s.s., and using the cox1, nad1, and nad5 genes, respectively, 17, 14, and 11 isolates corresponded to Elodea canadensis (genotype G6/G7). In the three study areas, G1 genotypes were the most prevalent. There were 233 mutation sites along with 129 parsimony informative sites. A transition/transversion ratio of 7.5, 8, and 3.25, respectively, for cox1, nad1, and nad5 genes was obtained. Every mitochondrial gene had intraspecific variations, which were represented in a star-like network with a major haplotype with observable mutations from other distant and minor haplotypes. The Tajima's D value was significantly negative in all populations, indicating a substantial divergence from neutrality and supporting the demographic expansion of E. granulosus s.s. in the study areas. The phylogeny inferred by the maximum likelihood (ML) method using nucleotide sequences of cox1-nad1-nad5 further confirmed their identity. The nodes assigned to the G1, G3, and G6 clades as well as the reference sequences utilized had maximal posterior probability values (1.00). In conclusion, our study confirms the existence of a significant major haplotype of E. granulosus s.s. where G1 is the predominant genotype causing of CE in both livestock and humans in China.

The impact of echinococcosis interventions on economic outcomes in Qinghai Province of China: Evidence from county-level panel data

INTRODUCTION

Echinococcosis can incur substantial economic losses for the livestock industry by causing organ condemnation, delayed growth, and reduced meat and wool output and quality in sheep and cattle, as well as increased surgery costs, hospital care, and decreased productivity in humans. Yet echinococcosis could be prevented and controlled by interventions, such as dog management and deworming, lamb vaccination, slaughter management, and training and public education.

METHODS

Exploiting temporal and spatial variations in the number of intervention measures implemented in 39 counties in Qinghai province of China in 2015-2020, this study assesses the economic impact of echinococcosis interventions using a dynamic difference-in-differences model.

RESULTS

The results suggest that echinococcosis interventions brought about substantial economic gains measured by per capita net income of rural residents and per capita gross output of animal husbandry. These economic gains are greater in non-pastoral counties (with a gain in per capita net income of rural residents of 3,308 yuan and a gain per capita gross output of animal husbandry of 1,035 yuan) than in pastoral counties (with a gain in per capita net income of rural residents of 1,372 yuan and a gain per capita gross output of animal husbandry of 913 yuan). They are also greater in counties with echinococcosis infection level-2 (with a human infection rate of 0.1-1% or a dog infection rate of 1-5%) than infection level-1 counties (with a human prevalence rate ≥1% or a dog infection rate ≥5%).

DISCUSSION

Not only will these economic gains encourage livestock farmers to strengthen their echinococcosis prevention and control practices, but they will also inform public policy on zoonotic disease prevention and control in China and other countries alike.

The Prevalence of Trichinella spiralis in Domestic Pigs in China: A Systematic Review and Meta-Analysis

The meta-analysis was performed to assess the prevalence of T. spiralis in domestic pigs in China. The potential studies from seven databases (Pubmed, Web of science, Scopus, Google Scholar, CNKI, Wanfang, CBM) were searched. I², Cochran's Q statistic and the funnel plot and Egger's test were used to assess heterogeneity and publication bias, respectively. In this study, a total of 179 articles were captured in the initially screened. Of these, we finally obtained 39 significant articles (including 43 studies involving in 551,097 pigs) for the final analysis. We calculated using a random-effects model, and we found the overall infection rate was 0.04 (95% CI 0.03-0.06). The highest prevalence region was Guangxi. The funnel plot and Egger's test showed no publication bias in our meta-analysis. In addition, this high heterogeneity index was suggestive of potential variations which could be due to regions, quality scores, detection methods, publication years, or samplings. These results indicated that T. spiralis were still prevalent in some areas in China. This highlights the need for an increased focus on implementing affordable, appropriate control programs to reduce economic losses and T. spiralis infection in domestic pigs in China.

Genetic diversity and haplotype analysis of yak and sheep echinococcal cysts isolates from the mitochondrial cox1 gene in parts of Tibet, China

Echinococcosis, also known as hydatid disease, is caused by the metacestode stage of the species cluster Echinococcus granulosus sensu lato (E. granulosus s.l.). It is almost widespread worldwide, especially in countries and regions dominated by animal husbandry. It is a major parasitic disease that seriously endangers human health, public health safety, environmental safety, and the development of animal husbandry production in western China. In this study, the mitochondrial cox1 gene was used to analyze the genetic diversity and haplotype of bovine and sheep echinococcal cysts isolated in Tibet. Echinococcus granulosus sensu stricto (E. granulosus s.s., G1, G3) was still the dominant species in the infected samples of yak and sheep in some parts of Tibet. Through haplotype analysis, Hap_1 was deemed the dominant haplotype, 14 of the 20 haplotypes were similar to the reference sequence previously published in Genbank, and the rest of the 6 haplotypes were found for the first time. Through Tajima's D value, neutral test Fu's Fs analysis, and haplotype network map, it can be concluded that Echinococcus population expansion has occurred in Xigaze, Tibet. This study provides basic data for understanding the genetic characteristics, epidemiology, and control of echinococcosis in this area.

Meta-analysis of the prevalence of bovine cystic echinococcosis in China during decade

BACKGROUND

Cystic echinococcosis (CE) is a zoonotic parasitic disease caused by Echinococcus granulosus sensu lato (E. granulosus s.l.) larvae. It is mainly prevalent in western agricultural and pastoral areas in China, seriously affecting the development of public health and animal husbandry.

METHODS

This study conducted a systematic evaluation and meta-analysis of bovine CE in China in the past 10 years (2011-2020). Five databases (PubMed, ScienceDirect, CNKI, Wanfang Data, VIP Chinese Journal Database) were used to collect the relevant references, and finally 77 published articles were obtained.

RESULTS

The total prevalence of bovine CE was estimated to be 9.62% during decade, and decreased year by year after reaching its peak in 2014 (18.75%). The highest E. granulosus s.l. infection rate was found in Qinghai province (14.79%). The infection rate of cattle >4 years old (15.84%) was significantly higher than that of other age groups, and cattle raised by grazing was significantly higher than that of other methods (17.00%). In the groups of geographical and climatic factors, the prevalence of CE was higher in regions with high-altitude (20.76%), cold (20.76%) and rainy areas (11.33%).

CONCLUSION

This study found that old age and grazing were two important factors for the high incidence of bovine CE. The prevalence of CE is higher in low temperature, rainy and high altitude areas, where may be more suitable for the survival of E. granulosus s.l. eggs.

Global Prevalence of Echinococcosis in Goats: A Systematic Review and Meta-Analysis

Echinococcosis is a foodborne parasitic zoonosis caused by the larvae of Echinococcus. This disease can affect goats and other mammals. In this study, a systematic review and meta-analysis for echinococcosis in global goats were performed based on the following five databases (China National Knowledge Infrastructure [CNKI], VIP Chinese Journal Database, Wanfang Data, PubMed, and ScienceDirect). In total, 108,197 samples were collected. The global prevalence of echinococcosis in goats was identified to be 10.85% (3217/108,197). The prevalence of echinococcosis in goats was 6.16% (1369/22,208) and 13.27% (874/5932) in South America and Africa, respectively. The prevalence of echinococcosis in goats before 2010 (9.76%; 112/713) was significantly higher than that from 2010 to 2014 (1.44%; 45/32,145) or after 2014 (2.95%; 154/3889). The prevalence of echinococcosis in goats aged <12 months (4.48%; 70/2911) was higher than that in goats aged ≥12 months (2.88%; 36/819). We also investigated the effects of geographical factors and climates on the prevalence of echinococcosis in goats. The results showed that the prevalence of echinococcosis was higher in the areas with high altitude and cold climate. This meta-analysis indicated that echinococcosis was ubiquitous in goats. Thus, we should improve the feeding conditions for goats, and strengthen the control measures of echinococcosis epidemic in goats, with the aims of reducing the economic losses of animal husbandry and providing protection for humans in the aspects of food security and health.