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.

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.

2000—2002年和2014—2017年分别采用整群抽样的方式对石渠县7、 8个乡镇中的行政村进行调查,采用超声影像学检查辅以血清学检测的方法对棘球蚴病患者进行诊断,比较两时间段内棘球蚴病患者性别、年龄、病灶大小、分型等的构成特点。2000—2002和2014—2017年分别调查416例和2 090例棘球蚴病患者。石渠县细粒棘球蚴病（CE）患者比例由2000—2002年的51.9%（216/416）下降至2014—2017年的39.8%（832/2 090）,多房棘球蚴病（AE）患者比例由2000—2002年的48.1%（200/416）上升至2014—2017年的57.4%（1 200/2 090）（P ＜0.05）; CL、 CE1、 CE2患者比例由2000—2002年的2.4%（10/416）、 18.0%（75/416）、 13.0%（54/416）分别下降至2014—2017年的0.7%（14/2 090）、 4.6%（96/2 090）、 6.0%（125/2 090）（P ＜0.05）, CE3、 CE4、 CE5患者比例由2000—2002年的5.5%（23/416）、 11.5%（48/416）、 1.4%（6/416）分别上升至2014—2017年11.1%（232/2 090）、 14.1%（294/2 090）、 3.4%（71/2 090）（P ＜0.05）; AE钙化结节型患者比例由2000—2002年的10.3%（43/416）上升至2014—2017年的21.2%（444/2 090）（P ＜0.05）, AE液化空洞型患者比例由2000—2002年的18.3%（76/416）下降至2014—2017年的13.6%（284/2 090）（P ＜0.05）,且病灶直径＜5 cm的AE患者比例由2000—2002年的15.1%（63/416）上升至2014—2017年的25.7%（523/2 032）（P ＜0.05）; CE患者比例,21～30岁年龄组2000—2002年（10.6%, 44/416）高于2014—2017年（4.5%, 92/2 032）（P ＜0.05）, 41～50岁及≥61岁年龄组2000—2002年（8.7%, 36/416; 5.3%, 22/416）低于2014—2017年（9.8%, 199/2 032;6.9%, 141/2 032）（P ＜0.05）。石渠县经过十余年的综合防治,棘球蚴病患者的构成情况呈现CE患者比例降低,AE患者比例增高,病灶分型、大小、年龄构成也有相应变化。

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.

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.

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 (β=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.

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.

Objective To understand the status of Cysticercus cellulosae infection and its impact on the mathematical learning ability among school-aged children in Tibetan agricultural areas of Sichuan Province.Methods In October 2015,a multistage stratified cluster sampling method was used to employ five-and six-grade children in all primary schools located in agricultural areas in three Tibetan counties (Muli County in Liangshan Prefecture,Yajiang County in Ganzi Prefecture,and Ruoergai County in Aba Prefecture).A survey was made among children in the form of structured questionnaire.The questionnaire content included the social demographics (gender,age,ethnicity,household asset,educational level of parents,number of children in the family),academic performance at school (math score and absence from school in the last semester) and self-reported conditions (seizure,headache,fatigue,and nausea).The mathematical learning ability of school-aged children was evaluated using the international standard mathematical ability test (hereinafter,the mathematical test),which was performed by well-trained investigators and children completed the test by themselves within prescribed time.Serum samples were collected from children to detect the antibodies against C.cellalosae using the enzyme-linked immunosorbent assay (ELISA) method.The independent impact of C.cellulosae infection on the mathematical learning ability was analyzed with the multivariable linear regression.Results 3 041 children in our sample,and 2 682 children participated in all the questionnaire survey,the mathematical test and serological examination.The mean score of the mathematical test was 55.65± 17.15.The C.cellulosae seropositive rate was 6.67％(179/2 682).Among the seropositive students,72.07％(129/179) reported headache,37.99％(68/179) reported frequent fatigues,5.59％ (10/179) reported frequent feelings of nausea,and 2.80％(5/179) reported occurrence of seizure.129 children were seropositive accompanied by headache,whose mean score of the mathematical test was 52.33 ± 1.46,1 648 children were seronegative accompanied by headache,whose mean score of the mathematical test was 55.94± 0.43,and the difference of mathematical test score in two types children was statistically significant (t =2.28,P ＜ 0.05).After controlling the factors of social demographics and academic performance at school,the multivariable linear regression analysis showed that the factor of seropositive accompanied by seizure,and seropositive accompanied by headache were statistically significant(β =-18.02,-4.06;P ＜ 0.05).Besides,the household asset,the educational level of mother and the number of children in the family were relevant to the mathematical test score of children (β =2.61,3.86,-6.19;P ＜ 0.01).Conclusion The epidemiological status of C.cellulosae infection among children in Tibetan agricultural areas is becoming a problem that needs more attention.C.cellulosae infection has shown detrimental effects on children's mathematical learning ability to some extent.

OBJECTIVE To evaluate the ELISA kit for detection of IgG antibodies against Taenia solium cysticercus in humans, so as to provide a reference for its application in clinical practice. METHODS The sera collected from the patients with neurocysticercosis, echinococcosis, taeniasis and healthy people, respectively, were checked by ELISA for specific IgG antibodies against T. solium cysticercus, as described in the instruction of the kit. RESULTS Of the 30 patients with neurocysticercosis at active stage, 28 showed seropositive reaction, indicating a sensitivity of 93.33%. There were no positive reactions in the 100 healthy people. Two of the 42 persons with taeniasis were seropositive with an infection rate of 4.76%. Forty-one of the 60 persons with echinococcosis showed positive reactions, suggesting that the cross reaction rate of the kit with echinococcosis was 68.33%. CONCLUSIONS The assessed ELISA kit has a reasonably high sensitivity but a poor specificity, and the cross reaction rate with echinococcosis is very high. It is urgent to improve the sensitivity and specificity of the diagnostic kit for detection of T.solium cysticercosis in China.

BackgroundCysticercosis, an infection caused by the larval stage of Taenia solium, is a serious but neglected disease in developing countries. Information about the prevalence of taeniasis, the gastrointestinal infestation with the adult tapeworm, and cysticercosis is lacking in China. In the current study, we aimed to understand the prevalence of T solium taeniasis and cysticercosis in children in a Tibetan region of western Sichuan.MethodsA cross-sectional study was conducted through cluster sampling in two Tibetan primary schools of Muli County, Liangshan Prefecture, in 2016. Sample collection in two schools was carried out in April and September, respectively, whereas treatment of taeniasis carriers was performed in December. Each student was questioned about a history of segment expulsion within the previous year by showing a segment photo, and also provided faecal and blood samples. All faecal samples were examined for presence of Taenia spp eggs by direct smear, and serum samples were tested for specific IgG antibodies to T solium cysticercus using an ELISA based on low-molecular-weight antigens of T solium cyst fluids. Treatment with pumpkin seeds combined with areca nut extract was provided to confirmed (stool-positive for Taenia spp eggs by microscopy) and suspected taeniasis carriers (reporting a history of segment expulsion within the previous year). All collected tapeworms following treatment were subject to morphology examination and genotyping by multiplex PCR. χ2 test was used to compare the infection rate of T solium taeniasis and seroprevalence in different groups of students. Significance was set at p≤0·05. Informed consent was obtained and Institutional Review Board approval was received.FindingsA total of 636 students (mean sampling coverage 90%) were involved in the study, with a median age of 11 years (range 5–15). The overall prevalence of taeniasis due to all three endemic Taenia species (T solium, T saginata, and T asiatica) was 10·4% (95% CI 7·9–12·9). The prevalence of T solium taeniasis was 6·1% (95% CI 4·2–8·0). Eight (23%) of 35 T solium taeniasis carriers expelled multiple tapeworms (range 2–11), including concurrent infection with other Taenia species. The prevalence of T solium cysticercosis IgG antibodies was 12·9% (95% CI 10·4–15·4) in 619 tested students. Of 32 students with T solium taeniasis, 13 (41%) were seropositive, compared with 12% (63/529) in the group of students without T solium taeniasis (p<0·0001). When analysed separately, the two schools had similar T solium taeniasis prevalence and cysticercosis antibody seroprevalence.InterpretationThe current study suggests that the prevalence of T solium taeniasis and cysticercosis is high in schoolchildren in Tibetan rural areas of western Sichuan. Further studies to better understand transmission patterns and risk factors in poor-resource rural areas of western China are needed to aid further eradication efforts.FundingGlobal Development and Poverty Initiative at Stanford University, Sichuan Provincial Department of Finance, and Science and Technology Department of Sichuan Province (2014SZ0151).

An adult hymenolepidid tapeworm was recovered from a 52-year-old Tibetan woman during a routine epidemiological survey for human taeniasis/cysticercosis in Sichuan, China. Phylogenetic analyses based on sequences of nuclear 28S ribosomal DNA and mitochondrial cytochrome c oxidase subunit 1 showed that the human isolate is distinct from Hymenolepis diminuta and Hymenolepis nana, the common parasites causing human hymenolepiasis. Proglottids of the human isolate were unfortunately unsuitable for morphological identification. However, the resultant phylogeny demonstrated the human isolate to be a sister species to Hymenolepis hibernia from Apodemus mice in Eurasia. The present data clearly indicate that hymenolepidid tapeworms causing human infections are not restricted to only H. diminuta and H. nana.

目的 通过观察和比较不同药物组合对带绦虫感染者的驱绦效果及不良反应,探讨在高度流行区开展群体性服药,控制带绦虫病流行的安全、有效的方法和途径. 方法 将四川省藏区雅江县查出的带绦虫病患者,在自愿服药的基础上随机分为3组,分别采用南瓜子-槟榔-硫酸镁,氯硝柳胺-硫酸镁和吡喹酮-硫酸镁驱虫,观察驱绦效果和可能发生的不良反应. 结果 南瓜子槟榔组、氯硝柳胺组、吡喹酮组治疗后5h内排出完整虫体的比率分别为77.14％(27/35),40.54％(15/37),47.37％(18/38),差异有统计学意义(x2=10.93,P＜0.01);而氯硝柳胺组与吡喹酮组间比较,差异无统计学意义(x2 =0.35,P＞0.05);药物不良反应发生率分别为48.57％、35.14％和39.47％,差异无统计学意义(x2 =1.10,P＞0.05).患者服药后出现的不良反应均不需做任何特殊处理即可缓解. 结论 在带绦虫病高度流行的藏区,采用南瓜子-槟榔-硫酸镁驱治绦虫,效果好且安全,可为人群接受,是一种值得推广应用的治疗带绦虫感染的方法.

目的 了解四川省藏族农区和彝族地区肠道蠕虫感染现状.方法 对省内甘孜州3个藏族县和凉山州1个彝族县3岁以上的部分人群用粪便生理盐水直接涂片显微镜查蠕虫卵.结果 共检查了2 653人,其中424人感染肠道蠕虫,感染率为15.98％.查出的肠道蠕虫有蛔虫、鞭虫和蛲虫等土源性线虫以及带绦虫,土源性线虫感染率为10.74％,带绦虫感染率为5.24％.藏区和彝区均有带绦虫分布,感染率分别为5.52％和1.57％.土源性线虫彝区感染率为80.63％,藏区5.32％.青壮年带绦虫病感染率明显高于其他年龄段人群,而青少年和儿童土源性线虫感染率最高.结论 四川省藏族农区和彝族地区带绦虫病高度流行,土源性线虫在彝族地区的流行尤为严重.相关部门应给予高度重视,综合性防控措施急需实施以减轻疾病危害、维护社会稳定.

SUMMARY 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.

To investigate echinococcosis in co-endemic regions, three polymerase chain reaction (PCR) assays based on the amplification of a fragment within the NADH dehydrogenase subunit 1 (ND1) mitochondrial gene were optimized for the detection of Echinococcus shiquicus, Echinococcus granulosus G1, and Echinococcus multilocularis DNA derived from parasite tissue or canid fecal samples. Specificity using parasite tissue-derived DNA was found to be 100% except for E. shiquicus primers that faintly detected E. equinus DNA. Sensitivity of the three assays for DNA detection was between 2 and 10 pg. Ethanol precipitation of negative PCR fecal samples was used to eliminate false negatives and served to increase sensitivity as exemplified by an increase in detection from 0% to 89% of E. shiquicus coproDNA using necropsy-positive fox samples.

Upper left: Yak herd crossing a river on the Tibetan plateau (altitude 4200m), Shiqu prefecture, Western Sichuan, July 2002.Lower left: Winter pastures in the Niniu valley (altitude 4200 m), Western Sichuan, May 2006.Central image: Echinococcoses, cysticercosis and taeniases represent a large disease burden in China and neighbouring countries.Coloured circles locate some of the areas where international and multidisciplinary research programmes on the transmission of both E. granulosus and E. multilocularis have been carried out during the last 20 years (see legend in Giraudoux et al. in this Special Issue of Parasitology).Upper right: Tibetan family resting after fi eld work, Niniu village, Western Sichuan, May 2006.Note the grandmother patting the young dog which is lying alongside a yak dung heap, almost certainly mixed with dog faeces, and the child thumb sucking, all behaviours which confer a high risk for the transmission of Echinococcus infection.Lower right: Dogs scavenging on a sheep carcass in the vicinity of Sary-Mogol village (altitude 3000 m), Alay valley, South Kyrgyztan, May 2012.

A 43-year-old Tibetan woman living in northwest Sichuan, China, confirmed to be a taeniasis carrier of Taenia solium was treated with pumpkin seeds combined with Areca nut extract in October 2009. All 20 tapeworms except one without scolex were expelled under good conditions. She was free of secondary cysticercosis within one year follow up. Although the first choice for treatment of taeniasis is still praziquantel, it may often cause serious side effect on asymptomatic cysticercosis cases to suddenly become symptomatic within a half day of the treatment. Therefore, the problems in treatment of taeniasis and/or cysticercosis in Asia are briefly overviewed, since other platyhelminthic diseases including schistosomiasis, opisthorchiasis etc. are more common and praziquantel is strongly recommended for mass treatment of these trematodiases with no idea on the co-infection with eggs of T. solium which cause asymptomatic cysticercosis.

SUMMARY 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.

SUMMARY 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’.