[A Social Network Perspective on the Transmission of Cysticercuscellulose Infections in Tibetan School Children in Sichuan].

OBJECTIVE: To determine the transmission characteristics of Cysticercuscellulose infections from a social network perspective in Tibetan school children in Sichuan. METHODS: A cluster sampling strategy was adopted to select two primary schools with high level of Cysticercuscellulose infections in the Tibetan agriculture areas of Liangshan prefecture, Sichuan province. All of the students from the selected schools were enrolled in the study. Their social network data, including classroom seating, dormitory roommates, best playmates, and those who shared meals and snacks etc, were collected by trained investigators. Stool and blood samples of the students were collected for parasite detection. The transmission network of Cysticercuscellulose infections and the overall social network of school children were analysed. RESULTS: A total of 644 children participated in the study. Taenia solium were found in 6.11% of the stool samples and 13.25% blood samples returned with seropositive. The transmission was centered around the sources of infections: dormitory-clustering in the boarding school and playmate-clustering in the day school. The overall social network analysis revealed "core people" (more relationships), "information disseminators" (closer to other nodes) and "information hubs" (between two nodes) in both schools. CONCLUSION: Close contacts in dormitories and playgrounds are the main sources of transmission of cysticercosis in the Tibetan schools. The "core people" "information disseminators" and "information hubs" are critical for the prevention and control of cysticercosis in the future.

[Impact of the neglected Cysticercus cellulose infection on mental health among school-aged children in Tibetan agricultural areas].

OBJECTIVE: To determine the impact of Cysticercus cellulose (C. cellulose) infection on mental health among school-aged children in Tibetan agricultural areas of Sichuan Province.
 Methods: In October 2015, all primary schools located in Tibetan agricultural areas in Yajiang, Ruoergai, and Muli county of Sichuan Province were selected as the research sites. All school-aged children at five- and six-grade were enrolled for the study by a multistage stratified cluster sampling method. Antibodies against C. cellulose were detected. Mental Health Test and questionnaire survey were conducted for school-aged children to collect data. The impact of C. cellulose infection on mental health among school-aged children was analyzed with the multilevel linear regression.
 Results: A total of 2 453 school-aged children were investigated. The C. cellulose seropositive rate was 6.03% (148/2 453). There were 0.16% (4/2 453) patients with seropositive accompanied by seizure, 2.28% (56/2 453) with seropositive accompanied by headache, 2.08% (51/2 453) with seropositive accompanied by frequent weak, and 0.41% (10/2 453) were seropositive accompanied by frequent nausea. The rate of C. cellulose infection was 4.53% (111/2 453). The mean score of the mental health test was 6.59±2.61. There were significant difference in score of mental health test in children whose demographic characteristics were different. The mental health scores of school-aged children were clustered at the school level. After controlling the factors of demographic characteristics, the result of multilevel model demonstrated that the factor of school-aged children with C. cellulose seropositive accompanied by headache was statistically significant (ß=1.14, P=0.017).
 Conclusion: The status of C. cellulose infection among school-aged children in Tibetan agricultural areas is not optimistic. C. cellulose infection has impacted on mental health of local school-aged children. It is necessary to strengthen the prevention and control of C. cellulose infection in epidemic area.

[Endemic situation and control progress of taeniasis in western China].

Taeniasis, caused by Taenia species, is one of the common zoonoses in China, particularly in the western region of China. Up to now, not enough attention has been given in the high prevalence and high burden of the diseases. In order to study the endemic patterns and control strategies of taeniasis, a series of epidemiological investigations, molecular researches and pilot control activities have been conducted in recent years. This paper reviews the relevant publications in taeniasis research over the last 10 years.

Genotypic relationships between Taenia saginata, Taenia asiatica and their hybrids.

Partial sequences of the DNA polymerase delta (pold) gene from Taenia saginata-like adult worms were sequenced. Phylogenetic analysis revealed that pold gene sequences were clearly divided into two clades, differing from each other in five to seven nucleotides. There is little doubt that T. saginata and Taenia asiatica were once separated into two distinct taxa as has been concluded in previous studies. On the other hand, most of the adult worms, which were identified as T. asiatica using mitochondrial DNA, were homozygous for an allele that originated from the allele of T. saginata via single nucleotide substitution. These results indicate that most of the adult worms, which had been called T. asiatica, are not actually 'pure T. asiatica' but instead originated from the hybridization of 'pure T. saginata' and 'pure T. asiatica'.

Transmission ecosystems of Echinococcus multilocularis in China and Central Asia.

From continental to regional scales, the zoonosis alveolar echinococcosis (AE) (caused by Echinococcus multilocularis) forms discrete patches of endemicity within which transmission hotspots of much larger prevalence may occur. Since the late 80s, a number of hotspots have been identified in continental Asia, mostly in China, wherein the ecology of intermediate host communities has been described. This is the case in south Gansu, at the eastern border of the Tibetan plateau, in south Ningxia, in the western Tian Shan of Xinjiang, and in the Alay valley of south Kyrgyzstan. Here we present a comparative natural history and characteristics of transmission ecosystems or ecoscapes. On this basis, regional types of transmission and their ecological characteristics have been proposed in a general framework. Combining climatic, land cover and intermediate host species distribution data, we identified and mapped 4 spatially distinct types of transmission ecosystems typified by the presence of one of the following small mammal 'flagship' species: Ellobius tancrei, Ochotona curzoniae, Lasiopodomys brandtii or Eospalax fontanierii. Each transmission ecosystem had its own characteristics which can serve as a reference for further in-depth research in the transmission ecology of E. multilocularis. This approach may be used at fine spatial scales to characterize other poorly known transmission systems of the large Eurasian endemic zone, and help in consideration of surveillance systems and interventions.

Detection of human taeniases in Tibetan endemic areas, China.

Detection of taeniasis carriers of Taenia solium is essential for control of cysticercosis in humans and pigs. In the current study, we assessed the positive detection rate of a self-detection tool, stool microscopy with direct smear and coproPCR for taeniasis carriers in endemic Tibetan areas of northwest Sichuan. The self-detection tool through questioning about a history of proglottid expulsion within the previous one year showed an overall positive detection rate of more than 80% for Taenia saginata, T. solium and T. asiatica. The positive detection rate was similar for T. saginata and T. solium. In 132 taeniid tapeworm carriers, 68 (51·5%) were detected by microscopy and 92 (69·7%) were diagnosed by coproPCR. A combination of microscopy and coproPCR increased the positive detection rate to 77·3%. There remained 10 cases (7·6%) coproPCR negative but microscopy positive. Due to the high cost and complicated process, coproPCR is required for the identification of Taenia species only when necessary, though it had a significant higher positive detection rate than microscopy. Combined use of self-detection and stool microscopy are recommended in community-based mass screening for taeniases in this Tibetan area or in other situation-similar endemic regions.

Advances in diagnosis and spatial analysis of cysticercosis and taeniasis.

Human cysticercosis, caused by accidental ingestion of eggs of Taenia solium, is one of the most pathogenic helminthiases and is listed among the 17 WHO Neglected Tropical Diseases. Controlling the life-cycle of T. solium between humans and pigs is essential for eradication of cysticercosis. One difficulty for the accurate detection and identification of T. solium species is the possible co-existence of two other human Taenia tapeworms (T. saginata and T. asiatica, which do not cause cysticercosis in humans). Several key issues for taeniasis/cysticercosis (T/C) evidence-based epidemiology and control are reviewed: (1) advances in immunological and molecular tools for screening of human and animals hosts and identification of Taenia species, with a focus on real-time detection of taeniasis carriers and infected animals in field community screenings, and (2) spatial ecological approaches that have been used to detect geospatial patterns of case distributions and to monitor pig activity and behaviour. Most recent eco-epidemiological studies undertaken in Sichuan province, China, are introduced and reviewed.

Monetary burden of neurocysticercosis on a hospitalized population in Muli County, China.

Neurocysticercosis (NCC) is a potentially life-threatening condition caused by the zoonotic cestode, Taenia solium. Pigs are the typical intermediate hosts for T. solium but humans can become infected and develop NCC upon ingesting parasite eggs that are shed in the feces of an infected person. The objective of this study was to estimate the monetary burden of neurocysticercosis (NCC) on hospitalized patients from Muli County, China. Muli is an agricultural county in Liangshan Prefecture, Sichuan Province, China where pigs are raised and the zoonotic cestode, Taenia solium, is endemic. Demographic and treatment data were collected from the Muli County Health Insurance Department on hospitalized individuals with an NCC diagnosis between 2014 and 2021. These patients represent residents of Muli County that purchased health insurance and received treatment in a public hospital in Sichuan Province. Hospital costs were converted from Chinese renminbi (RMB) to United States dollars (US$) for month and year of hospitalization and adjusted for inflation. Individuals with missing hospital information were excluded from analysis. For indirect costs, annual average salary for Liangshan Prefecture working-age adults was obtained to calculate productivity losses based on number of hospitalization days and travel days to and from the hospital. Transportation costs were evaluated based on estimated bus fare to and from the hospital. Out of 70 patients identified from 2014 to 2021, 68 had complete records, of which 47.1% were male (n = 33) and the median age at first hospitalization was 34 years. Total estimated cost for these patients was US$228,341.98. Direct costs contributed 62.5% (US$142,785.25) and indirect costs were 37.5% (US$85,556.73) of the total cost. The estimated median cost per case was US$2,078.69. Individuals with a single hospitalization (n = 41) cost a median of US$1,572.03 and those with multiple hospitalizations (n = 27) cost a median of US$4,169.95. The median total cost per NCC case was 18.6% of the average wage for a Liangshan Prefecture resident in 2021. While the study was limited to those with insurance coverage, monetary burden on the local population is likely substantial. Public health policies aimed at reducing transmission should be implemented to decrease the economic burden of NCC on this region.

Specific detection of Echinococcus spp. from the Tibetan fox (Vulpes ferrilata) and the red fox (V. vulpes) using copro-DNA PCR analysis.

There are three Echinococcus species, Echinococcus granulosus, E. multilocularis, and E. shiquicus, which are distributed on the vast area of pastureland on the eastern Tibetan plateau in China. Tibetan foxes (Vulpes ferrilata) have been determined to be the main wild definitive host of E. multilocularis and E. shiquicus, but little information is available on the prevalence of these two parasites in Tibetan foxes. Consequently, the copro-prevalence of these parasites in foxes from the eastern Tibetan plateau was evaluated in this study. For each copro-DNA sample extracted from fox feces, a 133-bp segment of EgG1 Hae III was used to screen for infection with E. granulosus. Multiplex nested polymerase chain reaction (PCR) analysis was used to target an 874-bp segment of the mitochondrial COI gene to distinguish E. multilocularis and E. shiquicus. Among 184 fecal samples, 120 were from Tibetan foxes and six from red foxes (Vulpes vulpes). Of the fecal samples from Tibetan foxes, 74 (giving a copro-prevalence of 62%) showed the presence of Echinococcus spp.: 23 (19%) were found to contain E. multilocularis, 32 (27%) E. shiquicus, and 19 (16%) showed mixed infection with both E. multilocularis and E. shiquicus. Two fecal samples from red foxes were found to be infected with E. multilocularis. No fox feces were found to be infected with E. granulosus. Tests on zinc finger protein genes and a 105-bp fragment of the Sry gene found no significant difference in the prevalence of the two parasites between sexes. The efficiency of our multiplex nested PCR methods were compared with previous polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) methods and some problems associated with the copro-PCR were discussed.

Implementation of Taenia solium control measures in Bali, Indonesia: Survey findings and a historical overview.

Historically, cysticercosis cases caused by infection with the larval stage of the Taenia solium tapeworm have occurred sporadically in Bali, with taeniasis carriers found primarily in villages located in the Kubu subdistrict of Karangasem. As Bali is a well-known tourist destination, living standards are relatively high on the island, except for an area located beneath the northeast slope of the active volcano Mt. Agung (Alt. 3031 m), which includes Kubu. Over the last 30 years, pigs originating from this area have been found with T. solium cysticerci, whereas pigs from other parts of the island have not been shown to be infected. Out of 108 individuals screened via fecal sample examination in Kubu during 2019, 3 cases of T. solium taeniasis (2.8%) were identified. There was no significant difference in taeniasis prevalence from surveys conducted in 2011-2016 (1.0%, 11/1089) (p = 0.123). Out of 110 humans and 140 pigs tested serologically in Kubu during 2019, no cases of cysticercosis were identified. This is in contrast to a seroprevalence of 4.1% (42/1025) in humans during 2011-2016 and a seroprevalence of 13.1% (43/329) in pigs during 2011-2013. Over the last decade, improved drinking water and sanitary systems have been employed in addition to health education targeting primary school children, including emphasis on washing hands before eating and after defecation. This review provides previously unpublished survey data and a historical overview of T. solium infection in Bali and offers guidance on best practices to ensure that remaining pockets of transmission are addressed.

New insights on the Taenia solium tapeworm using molecular tools: age-based human definitive host prevalence and deliberation on parasite life span.

Information on age-based Taenia solium taeniasis prevalence is crucial for control of cysticercosis. T. solium taeniasis prevalence was determined for a village in Liangshan Prefecture, Sichuan Province, China that was co-endemic for T. solium, Taenia saginata asiatica, and Taenia saginata. Individuals who were Taenia egg-positive by stool microscopy and/or expelled tapeworms or proglottids post-treatment were diagnosed as having taeniasis. Infecting species was identified via multiplex PCR on tapeworm specimens or coproPCR followed by sequencing. In addition, initial stool samples from 10 children with taeniasis suspected of having spontaneous expulsion of tapeworms within the period between diagnosis and treatment were subject to species confirmation via coproPCR and sequencing. Of the 389 study subjects, 194 (49.9%) were diagnosed with taeniasis. Children (< 16 years of age) had a higher T. solium taeniasis prevalence (8.8%) than older individuals (2.5%) (P = 0.0127). Molecular analysis of initial stool samples from 7 of 10 children suspected of spontaneously passing tapeworms indicated 6 infections due to T. solium and 1 infection due to T. saginata. This study found that young children had a higher T. solium taeniasis prevalence than older individuals, providing additional support for the belief that adult T. solium likely has a relatively short lifespan compared to other Taenia species with human definitive hosts.

Evaluation of a loop-mediated isothermal amplification method using fecal specimens for differential detection of Taenia species from humans.

We compared the performance of loop-mediated isothermal amplification (LAMP) with that of a multiplex PCR method for differential detection of human Taenia parasites in fecal specimens from taeniasis patients. The LAMP method, with no false positives, showed a higher sensitivity (88.4%) than the multiplex PCR (37.2%). Thus, it is expected that the LAMP method has a high value for molecular diagnosis of taeniasis.

[Production of a monoclonal antibody specific to protoscolex of Echinococcus multilocularis].

OBJECTIVE: To prepare monoclonal antibody (McAb) specific to protoscolex of Echinococcus multilocularis. METHODS: BALB/c mice were immunized with crude antigen derived from E. multilocularis metacestodes. Spleen cells from immunized BALB/c mice were fused with SP2/0 myeloma cells by using hybridoma technique. ELISA and immunohistochemical staining were used to select hybridomas that secreted McAb P325 which especially against protoscolex. The number of metaphase chromosomes of hybridoma cells was counted. Characteristics of McAb P325 were identified by ELISA and immunohistochemical staining. RESULTS: One hybridoma cell clone secreting McAb against protoscolex was obtained. The number of metaphase chromosomes found in hybridoma cells was 98, which showed the characteristics of their parents. Immunohistochemical analysis showed that McAb P325 demonstrated binding activity to the germinal layer and protoscolex of E. multilocularis, especially to the hooklets and suckers, while did not bind with E. granulosus metacestodes and Cysticercus tenuicollis. CONCLUSION: The McAb is a valuable tool for immunohistochemical analysis, cell classification of E. multilocularis protoscolex, and study of specific antigen.

Taeniasis and cysticercosis in Asia: A review with emphasis on molecular approaches and local lifestyles.

Taeniasis is an important parasitic condition in Asia, especially since all three human-infecting Taenia spp., Taenia solium, Taenia saginata, and Taenia asiatica are found in this region. These three species are believed to be sympatrically distributed, with the largest disease burden found in remote and rural areas where people raise pigs and cattle in a traditional manner. Recent studies revealed that T. asiatica and T. saginata are genetically-related sister species that are not completely reproductively isolated from each other. Current evidence indicates that most T. asiatica adult worms are hybrid-derived descendants. Moving forward, nuclear DNA analysis will be critical in further assessing the species circulating locally. Lifestyle choices, such as the consumption of undercooked meat, are important in maintaining the life cycles of these parasites. In addition, poor hygiene and sanitation, in highly endemic areas, make disease control difficult, resulting in the need for sustainable education programs. An overview of the present situation of taeniasis and cysticercosis in Asia is provided, followed by a discussion of molecular approaches to species assessment and the impact of human lifestyles on parasite transmission.

High prevalence of taeniasis and Taenia solium cysticercosis in children in western Sichuan, China.

Data in China on human Taenia infections, including Taenia solium cysticercosis, is largely lacking. We aimed to determine the prevalence of taeniasis with all three human Taenia species as well as T. solium cysticercosis in primary school-aged children in minority areas of western Sichuan, China. During April 2016 to December 2017, we did a cross-sectional study in five western Sichuan Province primary schools in Liangshan (3 schools), Ganzi (1 school) and Aba (1 school) prefectures. Diagnosis of taeniasis was made by stool microscopy for presence of Taenia eggs, as well as recovery of taeniid tapeworms or proglottids by medicinal treatment followed by species identification using multiplex PCR. Diagnosis of T. solium cysticercosis was made serologically using an ELISA with low-molecular-weight antigens purified from T. solium cyst fluid to detect specific IgG antibodies. A total of 1672 children were screened for taeniasis and 1639 were evaluated for cysticercosis antibodies. Overall prevalence of taeniasis was 7.5% but was as high as 15.6% at one school site (e.g., Shuiluo). Of the three known human Taenia species, adult T. solium tapeworms were detected in 42 children from four of the five schools (all three schools in Liangshan and one in Aba), giving a prevalence of T. solium taeniasis of 2.5% (95% confidence interval 0-6.7%). Cysticercosis antibody seropositivity by school varied from 2.3% to 15.6% (overall 7.5%). T. solium taeniasis carriers were more likely to have cysticercosis antibodies than children without T. solium taeniasis (43.6% vs 6.6%). Schools with higher prevalences of T. solium taeniasis were more likely to have children with human cysticercosis IgG antibodies. This study shows a high prevalence of taeniasis and T. solium cysticercosis in primary school-aged children in minority areas of western Sichuan, suggesting an urgent necessity for school-based disease control.

Structural Equation Modeling (SEM) of Cysticercosis in School-Aged Children in Tibetan Rural Farming Areas of Western China: Implications for Intervention Planning.

Neurocysticercosis (NCC) significantly contributes to morbidity in developing countries. We recently published a study of prevalence and risk factors in school-aged children in three mountainous areas in Sichuan province of western China. Using structural equation modeling (SEM) on data from that study to guide intervention planning, here we examine risk factors grouped into three broad interventional categories: sociodemographics, human behavior, and sources of pork and pig husbandry. Because neuroimaging is not easily available, using SEM allows for the use of multiple observed variables (serological tests and symptoms) to represent probable NCC cases. Data collected from 2608 students was included in this analysis. Within this group, seroprevalence of cysticercosis IgG antibodies was 5.4%. SEM results showed that sociodemographic factors (ß = 0.33, p < 0.05), sources of pork and pig husbandry (ß = 0.26, p < 0.001), and behavioral factors (ß = 0.33, p < 0.05) were all directly related to probable NCC in school-aged children. Sociodemographic factors affected probable NCC indirectly via sources of pork and pig husbandry factors (ß = 0.07, p < 0.001) and behavioral variables (ß = 0.07, p < 0.001). Both sociodemographic factors (ß = 0.07, p < 0.05) and sources of pork and pig husbandry factors (ß = 0.10, p < 0.01) affected probable NCC indirectly via behavioral variables. Because behavioral variables not only had a large direct effect but also served as a critical bridge to strengthen the effect of sociodemographics and sources of pork and pig husbandry on probable NCC, our findings suggest that interventions targeting behavioral factors may be the most effective in reducing disease.

A multiplex PCR for differential detection of Echinococcus granulosus sensu stricto, Echinococcus multilocularis and Echinococcus canadensis in China.

BACKGROUND: Echinococcosis caused by Echinococcus is one of the most major infectious diseases in north-west highland of China. E. granulosus sensu strict, E. multilocularis, and E. canadensis are known to be the only three species related to human health transmitting in the areas. To achieve targeted treatment and control of echinococcosis, the accurate identification and discrimination of the species are important. However, currently the available diagnostic approaches do not present ideal results either in accuracy or efficiency. METHODS: In the study, a set of primers were designed to aim at the three human-pathogenic Echinococcus species in China. The one-step multiplex PCR assay was developed and evaluated for the specificity and sensitivity. A total of 73 parasitic lesions and 41 fecal materials obtained from human and various animals collected in the clinic and the field were tested to assess the applicability of this method. RESULTS: The multiplex PCR effectively detected the individual DNA from the targeted species and their random mixtures generating with distinguishable expected size of products. The detection limit of the assay for each of the three species was 5 pg/µl when they were tested separately. When DNA mixtures of the targeted species containing the same concentration were used as templates, the lowest amount of DNA which can be detected was 50 pg/µl, 10 pg/µl and 5 pg/µl for E. granulosus s. s., E. multilocularis, and E. canadensis respectively. No cross-reactivity was observed when DNA from eight genetically close species was used as control templates. The multiplex PCR identifications of all samples were in line with the original sequencing results except for those infected with E. shiquicus, which showed negative signals in the developed assay. Of all the tested stool materials, 16 were previously found positive for Echinococcus by visual and microscopic examination. Among these 16 samples, 13 were confirmed by the multiplex PCR, and the other three tested negative. Additionally, the multiplex PCR identified another 14 positive feces from the remained 25 stool samples which absence of worms. CONCLUSIONS: The developed multiplex PCR shows advantages in fast diagnosis and large-scale epidemiological investigation, which proven to be a promising tool utilized in clinic and surveillance system.

Species identification of human echinococcosis using histopathology and genotyping in northwestern China.

Human cystic echinococcosis, caused by infection with the larval stage of Echinococcus granulosus, and alveolar echinococcosis, caused by the larval form of E. multilocularis, are known to be important public health problems in western China. Echinococcus shiquicus is a new species of Echinococcus recently described in wildlife hosts from the eastern Tibetan plateau and its infectivity and/or pathogenicity in humans remain unknown. In the current study, parasite tissues from various organs were collected post-operatively from 68 echinococcosis patients from Sichuan and Qinghai provinces in eastern China. The tissues were examined by histopathology and genotyped using DNA sequencing and PCR-RFLP. Histopathologically, 38 human isolates were confirmed as E. granulosus and 30 as E. multilocularis. Mitochondrial cob gene sequencing and PCR-RFLP with rrnL as the target gene confirmed 33 of 53 of the isolates to have the G1 genotype of sheep/dog strain of E. granulosus as the only source of infection, while the remaining 20 isolates were identified as E. multilocularis. No infections were found to be caused by E. shiquicus. Additionally, 5 of 20 alveolar echinococcosis patients were confirmed to have intracranial metastases from primary hepatic alveolar echinococcosis lesions. All these cases originated from four provinces or autonomous regions but most were distributed in Sichuan and Qinghai provinces, where high prevalence rates of human alveolar echinococcosis and cystic echinococcosis were previously documented.

[Biological features of a new Echinococcus species (Echinococcus shiquicus) in the east of Qinghai-Tibet Plateau].

In the eastern Qinghai-Tibet Plateau region, a variety of domestic and wild mammals are involved in the transmission cycles of Echinococcus species. E. granulosus and E. multilocularis are known being sympatrically distributed in the plateau region. Recently, an unknown Echinococcus species was isolated from infected plateau pika (Ochotona curzoniae) and Tibetan fox (Vulpes ferrilata). The species shows quite distinct characteristics on morphology, genetics, host specificity and geographical distribution from others. It was therefore identified as a new Echinococcus species, Echinococcus shiquicus. This paper discussed the biological genetics and epidemiological features of the species, and proposed hypotheses and considerations for further exploration.

Epidemiology and risk factor analysis for canine echinococcosis in a Tibetan pastoral area of Sichuan.

OBJECTIVE: To determine the prevalence and evaluate the risk factors of canine echinococcosis based on a field survey of dog infections with Echinococcus granulosus and E. multilocularis in Chalong, Kalong, Dade and Chazha Townships in a district of Ganzi County, Sichuan Province, China. METHOD: Questionnaire associated with the acquisition of canine echinococcosis was administered to dog owners. Stray dogs were examined post-mortem and rectal faeces at necropsy were collected to validate a copro-antigen ELISA. Owned dogs were screened for Echinococcus spp. infection in faeces using the genus specific copro-ELISA and the effectiveness of dog treatment was assessed. Chi-square and one-way ANOVA were used for statistical analysis. RESULTS: The prevalence of Echinococcus spp. infection at necropsy in stray dogs was 60.9% (14/23) in 2000; E. multilocularis infection accounted for 34.8% (8/23) and E. granulosus for 26.1% (6/23). The specificity of the copro-ELISA was 80.0% and the sensitivity was 92.3%, compared with the results at necropsy. Fifty percent of owned dogs (290/580) tested was copro-antigen positive at the beginning of the project in 2000, which decreased to 17% (99/580) in the same cohort of owned dogs after praziquantel treatment (5 mg/ kg) at 6-monthly period from 2003 to 2005. Analysis for risk factors associated with copro-antigen positive dogs showed that the never tethered dogs had a higher rate (40.4%, 65/161) than dogs tethered during the day (32.3%, 109/337), or tethered at night [29.2% (21/72)], or those always tethered [20%(2/10)](P<0.01). Dogs that their owners lacked hydatid transmission knowledge [38.1% (121/318)] and did not have de-worming practice [47.7% (92/193)] had significantly higher copro-antigen positive rate than those dogs that their owners knew relevant knowledge [28.6% (75/262)] and were dewormed regularly [20.4% (79/387)](P<0.05 and P<0.01). There was no correlation between the prevalence and dog sex or age or the varieties of livestock that the owner raised. CONCLUSION: Local dogs show high prevalence with both E. granulosus and E. multilocularis. The copro-ELISA can be used to detect infection of Echinococcus in dogs. Allowing dogs to roam, lack of the basic knowledge of hydatid disease transmission and no de-worming practice for dogs are significant factors for the transmission of canine echinococcosis.