Prevalence and spatial distribution characteristics of human echinococcosis in China

Background Echinococcosis is a zoonotic parasitic disease caused by larval stages of cestodes belonging to the genus Echinococcus. The infection affects people’s health and safety as well as agropastoral sector. In China, human echinococcosis is a major public health burden, especially in western China. Echinococcosis affects people health as well as agricultural and pastoral economy. Therefore, it is important to understand the prevalence status and spatial distribution of human echinococcosis in order to advance our knowledge of basic information for prevention and control measures reinforcement. Methods Report data on echinococcosis were collected in 370 counties in China in 2018 and were used to assess prevalence and spatial distribution. SPSS 21.0 was used to obtain the prevalence rate for CE and AE. For statistical analyses and mapping, all data were processed using SPSS 21.0 and ArcGIS 10.4, respectively. Chi-square test and Exact probability method were used to assess spatial autocorrelation and spatial clustering. Results A total of 47,278 cases of echinococcosis were recorded in 2018 in 370 endemic counties in China. The prevalence rate of human echinococcosis was 10.57 per 10,000. Analysis of the disease prevalence showed obvious spatial positive autocorrelation in globle spatial autocorrelation with two aggregation modes in local spatial autocorrelation, namely high-high and low-high aggregation areas. The high-high gathering areas were mainly concentrated in northern Tibet, western Qinghai, and Ganzi in the Tibetan Autonomous Region and in Sichuan. The low-high clusters were concentrated in Gamba, Kangma and Yadong counties of Tibet. In addition, spatial scanning analysis revealed two spatial clusters. One type of spatial clusters included 71 counties in Tibet Autonomous Region, 22 counties in Qinghai, 11 counties in Sichuan, three counties in Xinjiang Uygur Autonomous Region, two counties in Yunnan, and one county in Gansu. In the second category, six types of spatial clusters were observed in the counties of Xinjiang Uygur Autonomous Region, and the Qinghai, Gansu, and Sichuan Provinces. Conclusion This study showed a serious prevalence of human echinococcosis with obvious spatial aggregation of the disease prevalence in China. The Qinghai-Tibet Plateau is the "hot spot" area of human echinococcosis in China. Findings from this study indicate that there is an urgent need of joint strategies to strengthen efforts for the prevention and control of echinococcosis in China, especially in the Qinghai-Tibet Plateau.

Prevalence of Echinococcus Species in Wild Foxes and Stray Dogs in Qinghai Province, China

Echinococcosis is a zoonotic parasitic disease that is highly endemic to the Qinghai province of China. Limited data are available on the prevalence of the causal pathogen, Echinococcus spp., in definitive hosts in this region. Thus, the aim of this study was to evaluate the prevalence of Echinococcus spp. in wild foxes and stray dogs in Qinghai province. Five hundred and twenty-eight feces from wild foxes and 277 from stray dogs were collected from 11 counties in the Golog, Yushu, and Haixi prefectures and screened for Echinococcus spp. using copro-DNA polymerase chain reaction (PCR). In total, 5.5% of wild foxes and 15.2% of stray dogs tested positive for Echinococcus spp. The prevalence rates of Echinococcus spp. in wild foxes in Golog, Yushu, and Haixi were 7.3%, 5.2%, and 1.9%, respectively. In stray dogs, these rates were 13.3%, 17.3%, and 0%, respectively. Sequencing analysis determined that Echinococcus multilocularis was the most prevalent species, occurring in 4.0% and 12.6% of wild foxes and stray dogs, respectively. Echinococcus shiquicus was observed in 1.5% of wild foxes and 0.7% of stray dogs. Echinococcus granulosus was observed only in wild dogs, with a prevalence rate of 1.8%. To our knowledge, this is the first report on the prevalence of E. shiquicus in dogs in Qinghai province. The current results improve our understanding of the transmission and dissemination of human echinococcosis and suggest that exposure to the eggs of E. multilocularis harbored by wild foxes and stray dogs may pose a great risk of alveolar echinococcosis to humans in Qinghai province.

Geographic distribution and prevalence of human echinococcosis at the township level in the Tibet Autonomous Region

Background Echinococcosis is a zoonotic parasitic disease caused by larval stages of cestodes belonging to the genus Echinococcus. Echinococcosis is prevalent in 10 provinces/autonomous regions in western and northern China. A 2016 epidemiological survey of Tibet Autonomous Region (TAR) showed that the prevalence of human echinococcosis was 1.66% which is much higher than the average prevalence in China (0.24%). Therefore, understanding the prevalence and spatial distribution characteristics of human echinococcosis at the township level in TAR is critical. Methods Data from echinococcosis cases were obtained from 692 TAR townships in 2018. Cases were identified using the B-ultrasonography diagnostic method. The epidemic status of echinococcosis was classified in all townships in TAR according to the relevant standards of population prevalence indexes as defined in the national technical plan for echinococcosis control. Spatial scan statistics were used to highlight the geographical townships most at risk of echinococcosis. SPSS 21.0 was used to calculate the prevalence for cystic echinococcosis (CE) and alveolar echinococcosis (AE). For spatial clustering analyses and mapping, data were processed using ArcGIS 10.1. Spatial scan analyses were performed using SaTScan V9.5. Results In 2018, 16,009 echinococcosis cases were recorded in 74 endemic counties in TAR. The total prevalence rate was 0.53%. All the 692 townships were classified according to the order of the epidemic degree from high to low. 127 townships had prevalence rates higher than or equal to 1%. The spatial clustering scanning analysis of echinococcosis cases and exposed population showed that CE displayed one primary cluster, two secondary clusters and six minor secondary clusters. The primary cluster and other clusters were defined by Log-likelihood ratio (LLR) statistically significant values. The primary cluster covered 88 townships in 12 epidemic counties. AE displayed one primary cluster and two secondary clusters. The primary cluster covered 38 townships in 6 epidemic counties.

Geographical Detector-based influence factors analysis for Echinococcosis prevalence in Tibet, China

Echinococcosis, caused by genus Echinococcus, is the most pathogenic zoonotic parasitic disease in the world. In Tibet of the People’s Republic of China, echinococcosis refers principally to two types of severe zoonosis, cystic echinococcosis (CE) and alveolar echinococcosis (AE), which place a serious burden on public health and economy in the local community. However, research on the spatial epidemiology of echinococcosis remains inadequate in Tibet, China. Based on the recorded human echinococcosis data, maps of the spatial distribution of human CE and AE prevalence in Tibet were produced at city level and county level respectively, which show that the prevalence of echinococcosis in northern and western Tibet was much higher than that in other regions. We employ a geographical detector to explore the influencing factors for causing CE and AE while sorting information on the maps of disease prevalence and environment factors (e.g. terrain, population, and yak population). The results of our analysis showed that biological factors have the most impact on the prevalence of echinococcosis, of which the yak population contributes the most for CE, while the dog population contributes the most for AE. In addition, the interaction between various factors, as we found out, might further explain the disease prevalence, which indicated that the echinococcosis prevalence is not simply affected by one single factor, but by multiple factors that are correlated with each other complicatedly. Our results will provide an important reference for the evaluation of the echinococcosis risk, control projects, and prevention programs in Tibet.

Prevalence and spatial distribution patterns of human echinococcosis at the township level in Sichuan Province, China

Background Echinococcosis is a global zoonotic parasitic disease caused by Echinococcus larvae. This disease is highly endemic in Sichuan Province, China. This study investigates the prevalence and spatial distribution characteristics of human echinococcosis at the township level in Sichuan Province, geared towards providing a future reference for the development of precise prevention and control strategies. Methods Human prevalence of echinococcosis was evaluated using the B-ultrasonography diagnostic method in Sichuan Province between 2016 and 2019. All data were collected, collated, and analyzed. A spatial distribution map was drawn to intuitively analyze the spatial distribution features. Eventually, the spatial autocorrelation was specified and local indicators of spatial association (LISA) clustering map was drawn to investigate the spatial aggregation of echinococcosis at the township level in Sichuan Province. Results The prevalence of echinococcosis in humans of Sichuan Province was 0.462%, among which the occurrence of cystic echinococcosis (CE) was 0.221%, while that of alveolar echinococcosis (AE) was 0.244%. Based on the results of the spatial distribution map, a predominance of echinococcosis in humans decreased gradually from west to east and from north to south. The Global Moran’s I index was 0.77 (Z = 32.07, P < 0.05), indicating that the prevalence of echinococcosis in humans was spatially clustered, exhibiting a significant spatial positive correlation. Further, the findings of local spatial autocorrelation analysis revealed that the “high–high” concentration areas were primarily located in some townships in the northwest of Sichuan Province. However, the “low–low” concentration areas were predominantly located in some townships in the southeast of Sichuan Province. Conclusions Our findings demonstrated that the prevalence of echinococcosis in humans of Sichuan Province follows a downward trend, suggesting that the current prevention and control work has achieved substantial outcomes. Nevertheless, the prevalence in humans at the township level is widely distributed and differs significantly, with a clear clustering in space. Therefore, precise prevention and control strategies should be formulated for clusters, specifically strengthening the “high–high” clusters at the township level. Graphic Abstract

Epidemiological survey of human echinococcosis in east Gansu, China

Echinococcosis is endemic in pastoral regions of south, west and mid-Gansu province, China. The present study aimed to determine the prevalence of echinococcosis in east Gansu, and analyze its associated risk factors. A cross-sectional survey was conducted in 2011 in 12 villages of Xiaonangou township, Huan County in east Gansu province by ultrasound abdominal scan and auxiliary serotest, and a prevalence surveillance study from 2008 to 2014 was performed in one villages by ultrasonography screening. Questionnaire information analysis indicates that the risk factors are in association with the gender, age, and education level. The cross-sectional survey found a cystic echinococcosis prevalence of 2.21% (107/4837). Higher prevalence was seen in females (χ2 = 4.198, P < 0.05), older ages (> 60 years) (χ2trend = 96.30, P < 0.05), and illiterates (χ2 = 90.101, P < 0.05). Prevalence surveillance showed changing profile of 3.35% in 2011 to 0.88% (1/113) in 2014.

Evaluation of fecal immunoassays for canine Echinococcus infection in China

Human echinococcosis is present worldwide but it is in China that disease prevalence is the highest. In western China, especially in the Tibetan Plateau, the burden of echinococcosis is the most important. Dogs are a major definitive host of Echinococcus and monitoring the presence of Echinococcus worms in dogs is therefore essential to efficiently control the disease. Detection kits based on three different technologies including sandwich ELISA, (indirect) ELISA, and gold immunodiffusion, are currently marketed and used in China. The objective of this work was to assess the efficacy of these kits, in particular with respect to sensitivity and specificity. Four fecal antigen detection kits for canine infection reflecting the three technologies were obtained from companies and tested in parallel on 220 fecal samples. The results indicate that the performance is lower than expected, in particular in terms of sensitivity. The best results were obtained with the sandwich ELISA technology. The gold immunofiltration yielded the poorest results. In all cases, further development is needed to improve the performance of these kits which are key components for the control of echinococcosis.

Analysis of Spatial Distribution Characteristics of Human Echinococcosis at the Township Level in Sichuan Province, China

BackgroundEchinococcosis is a global zoonotic parasitic disease caused by the larvae of Echinococcus, which affects both humans and animals. In China, this disease is highly endemic in Sichuan Province. In this study, we investigated the prevalence and spatial distribution characteristics of human echinococcosis at the township level in Sichuan province, so as to provide a reference for the development of precise prevention and control strategies in the future.MethodsWe explored the prevalence of echinococcosis using the B-ultrasonography diagnostic method in Sichuan province between 2016 and 2019, where patients and transmission conditions had been identified in the past. All data were inputted using Epi-Info software, while SPSS software was used for statistical analysis. We then employed ArcGIS software to draw the spatial distribution map and perform trend surface analysis. Finally, Geoda software was used to analyze spatial autocorrelation and draw Lisa clustering map.ResultsA total of 2 542 135 people from 649 towns in 35 counties of Sichuan province were screened for echinococcosis, of which 11 743 echinococcosis patients were detected. The prevalence of echinococcosis in humans was 0.462%, among which the occurrence of cystic echinococcosis [CE] was 0.221%, while that of alveolar echinococcosis [AE] was 0.244%. We also observed that the predominance of echinococcosis in humans decreased gradually from west to east and from north to south based on the results of the spatial distribution map and trend surface analysis. The Global Moran's I index was 0.77 (Z = 32.07, P < 0.05), which indicated that the prevalence of echinococcosis in humans was spatially clustered, exhibiting a significant spatial positive correlation. Further, the findings of local spatial autocorrelation analysis revealed that the “high-high” concentration areas were primarily located in some townships in the northwest of Sichuan province. On the other hand, the “low-low” concentration areas were predominantly located in some townships in the southeast of Sichuan province. ConclusionOur findings demonstrated that the prevalence of echinococcosis in humans of Sichuan province is following a downward trend, implying that the current prevention and control work has achieved some substantial outcomes. However, the prevalence in humans at the township level is widely distributed and differs greatly, with a clear clustering in space. Therefore in the future, precise prevention and control strategies should be formulated for clusters, particularly strengthening the “high-high” clusters at the township level.

Seroprevalence of human Echinococcosis in a community living around slaughterhouses in Western Province in Sri Lanka

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