Human cystic echinococcosis in two Mongolian communities in Hobukesar (China) and Bulgan (Mongolia)

Prevalence and risk factors associated with human cystic echinococcosis in rural areas, Mongolia

Cystic echinococcosis is a chronic, complex and neglected zoonotic disease with considerable socio-economic impact on the affected population. Even though Mongolia is included in the list of high cystic echinococcosis risk countries, there has been very limited research and evidence on the prevalence or prevention of cystic echinococcosis. This field-based cross-sectional study to investigate the prevalence of cystic echinococcosis and its potential risk factors in Mongolia was conducted from April 2016 to March 2018. A total of 1,993 people were examined by ultrasound in five provinces of Mongolia. All cystic echinococcosis positive cases were classified according to the WHO-IWGE expert recommendations. The logistic regression model was used to detect the association between the presence of echinococcus infection and each potential risk factor. This was the first community survey based on ultrasound screening in Mongolia. We found 98 cystic echinococcosis cases (prevalence = 4.9%), including 85 abdominal ultrasound cystic echinococcosis positive cases and 13 abdominal ultrasound cystic echinococcosis negative cases (surgically treated cystic echinococcosis cases 11, and 2 confirmed cases of lung cystic echinococcosis by chestcomputed tomography in hospital of Ulaanbaatar). The prevalence of cystic echinococcosis varied greatly among different provinces, ranging from 2.0% to 13.1%. Children, elderly people and those with lower education had higher chances of getting cystic echinococcosis. Rather than dog ownership itself, daily practice for cleaning dog feces was associated with increased odds of cystic echinococcosis. The results of the present study show very high endemicity of cystic echinococcosis in Umnugovi province. Evaluation of potential risk factors associated with cystic echinococcosisshow high significance for following factors: demographics (age), social condition (education level) and hygiene practices (cleaning dog feces and use of gloves). Children under 18 and elderly people are considered as the most risk age groups in Mongolia.

Patients with cystic echinococcosis in the three national referral centers of Mongolia: A model for CE management assessment

Background

Mongolia is one of the endemic countries for cystic echinococcosis (CE), a zoonotic disease caused by the larval stage of Echinococcus granulosus. The goal of this study is to describe the current clinical management of CE in Mongolia, to capture the distribution of cyst stages of patients treated, and to contrast current practice with WHO-IWGE expert consensus.

Methods

Hospital records of CE patients treated between 2008 and 2015 at the three state hospitals and fulfilling the inclusion criterion ‘discharge diagnosis CE’ (ICD 10 code B.67.0–67.9) were reviewed. Demographical, geographical, clinical and ultrasonography (US) data were extracted and analyzed. The annual surgical incidence was estimated. The digital copies of US cyst images were independently staged by three international experts following the WHO CE cyst classification to determine the proportions of patients which ideally would have been assigned to the WHO recommended treatment modalities surgery, percutaneous, medical (benzimidazole) treatment and watch & wait.

Results

A total of 290 patient records fulfilled the inclusion criteria of the study. 45.7% of patients were below 15 years of age. 73.7% of CE cysts were located in abdominal organs, predominantly liver. US images of 84 patients were staged and assessed for interrater-agreement. The average raw agreement was 77.2%. Unweighted Kappa coefficient and weighted Kappa was 0.57 and 0.59, respectively. Mean proportions of images judged as stages CE1, CE2, CE3a, CE3b, CE4 and CL were 0.59, 0.01, 0.19, 0.08, 0.03 and 0.11, respectively. 40 cysts met the inclusion criteria of treatment modality analysis. The mean proportions of cases with a single cyst assigned to medical, percutaneous treatment, surgery and watch & wait were 52.5% (95% CI 42–65), 25.8% (95% CI 15–30), 5.1% (95% CI 0–10) and 3.3% (95% CI 0–10), respectively. 13.3% (95% CI 5–25) of cysts were staged as CL and therefore assigned to further diagnostic requirement.

Conclusion

WHO CE cyst classification and WHO-IWGE expert consensus on clinical CE management is not implemented in Mongolia. This results in exclusively surgical treatment, an unnecessary high risk approach for the majority of patients who could receive medical, percutaneous treatment or observation (watch & wait). Introduction of WHO-IWGE expert consensus and training in ultrasound CE cyst staging would be highly beneficial for patients and the health care services.

Cystic Echinococcosis (CE) is a zoonotic disease, commonly known as dog tapeworm. The disease is distributed globally and predominantly affects rural populations with limited access to health care. Following the expert consensus of the WHO-Informal Working Group on Echinococcosis (WHO—IWGE) patients with uncomplicated cysts are assigned on the basis of WHO cyst classification to four treatment modalities: medical (benzimidazoles), percutaneous, surgical treatment, and ‘watch & wait’. In Mongolia, one third of the population practices nomadic farming. These populations are heavily affected by CE. However, cyst staging and WHO-IWGE recommendations are not implemented and patients referred to the three national treatment centres receive surgical treatment. This exposes a large proportion of patients to an unnecessary high risk approach who could be treated–depending on cyst stage—with benzimidazoles, percutaneously or observed (watch & wait). We reviewed the hospital records of patients with CE and admitted between 2008 and 2015 to the three national CE treatment centres, retrospectively staged the cysts and assigned the patients to the four WHO-IWGE recommended treatment modalities. We found a high proportion of patients in the study population who would have most likely benefitted from non-surgical treatment options.

Knowledge, attitudes and practices related to cystic echinococcosis endemicity in Pakistan

BACKGROUND

Cystic echinococcosis (CE) is a human and animal health problem in many endemic areas worldwide. It is considered a neglected zoonotic disease caused by the larval form (hydatid cyst) of Echinococcus spp. tapeworm. There are limited studies on echinococcosis in Pakistan.

METHODS

A cross-sectional survey was conducted to find out recent knowledge, attitudes and practices on the occurrence of cystic echinococcosis in butchers and dog owners in both urban and rural areas of Rawalpindi/Islamabad regions, Pakistan. The quantitative data was collected in the form of questionnaires to investigate the knowledge and awareness of CE among community members and their routine practices that  were behind the factors involved in hydatid cyst infection. The practices and infrastructure of abattoirs/butcher shops and their role in transmission of cystic echinococcosis were also evaluated in the present study.

RESULTS

The participants involved in the study were dog owners and people who kept animals. A total of 400 people were interviewed and 289 questionnaires were received. The results showed that only 4.1% of people have heard about the disease, and 58.1% were closely associated with dogs. Sixty-three percent of dogs in study area were consuming uncooked organs (e.g. liver, lung, etc.) of slaughtered animals, while 100% of dogs at butcher shops were consuming uncooked organs. Home slaughtering was common in 20.06%. Among butchers, 32.3% had heard about zoonoses and 7.61% knew about CE. The statistical analysis showed that there was highly significant difference (P < 0.05) among most of the practices that were associated with the prevalence of CE.

CONCLUSIONS

It  was concluded from the present study that, the knowledge and awareness of CE among people of Rawalpindi/Islamabad were low. Because of dogs and poor knowledge of CE among community members and butchers, the transmission of echinococcosis is facilitated. Therefore, there is urgent need to strengthen awareness and health education among people, as well as proper practices related to the CE not only in the study area, but also in other areas of Pakistan.

Global Distribution of Alveolar and Cystic Echinococcosis

Alveolar echinococcosis (AE) and cystic echinococcosis (CE) are severe helminthic zoonoses. Echinococcus multilocularis (causative agent of AE) is widely distributed in the northern hemisphere where it is typically maintained in a wild animal cycle including canids as definitive hosts and rodents as intermediate hosts. The species Echinococcus granulosus, Echinococcus ortleppi, Echinococcus canadensis and Echinococcus intermedius are the causative agents of CE with a worldwide distribution and a highly variable human disease burden in the different endemic areas depending upon human behavioural risk factors, the diversity and ecology of animal host assemblages and the genetic diversity within Echinococcus species which differ in their zoonotic potential and pathogenicity. Both AE and CE are regarded as neglected zoonoses, with a higher overall burden of disease for CE due to its global distribution and high regional prevalence, but a higher pathogenicity and case fatality rate for AE, especially in Asia. Over the past two decades, numerous studies have addressed the epidemiology and distribution of these Echinococcus species worldwide, resulting in better-defined boundaries of the endemic areas. This chapter presents the global distribution of Echinococcus species and human AE and CE in maps and summarizes the global data on host assemblages, transmission, prevalence in animal definitive hosts, incidence in people and molecular epidemiology.

The present situation of echinococcoses in Mongolia

This review presents the historical and current situation of echinococcoses in Mongolia. Since the collapse of the Soviet Union in 1991, Mongolia's health surveillance infrastructure has been very poor, especially as it pertains to chronic diseases, including neglected zoonotic diseases (NZDs). Although there is anecdotal evidence of people dying from hepatic disease due to infection with the larval stage of Echinococcus spp., there are very few published reports. All confirmed cases of echinococcoses in Mongolia are from hospitals located in the capital city of Ulaanbaatar. Cases of cystic echinococcosis (CE), caused by either Echinococcus granulosus sensu stricto or Echinococcus canadensis are believed to be relatively common throughout Mongolia. In contrast, cases of alveolar echinococcosis (AE), caused by Echinococcus multilocularis, are believed to be rare. Recent wild-animal surveys have revealed that wolves (Canis lupus) are the major definitive hosts of E. canadensis, whereas both wolves and red foxes (Vulpes vulpes) are the primary definitive hosts of E. multilocularis. Although wild-animal surveys have begun to elucidate the transmission of Echinococcus spp. in Mongolia, there have yet to be large-scale studies conducted in domestic dogs and livestock. Therefore, further epidemiological studies, in addition to education-based control campaigns, are needed to help combat this NZD.

Independent evaluation of a canine Echinococcosis Control Programme in Hobukesar County, Xinjiang, China

•

Xinjiang is one of the most important foci of human cystic echinococcosis in the world.

•

A control programme, including PZQ dosing of dogs, began in Xinjiang in 2010.

•

The control programme was evaluated using LQAS sampling, dog necropsies and questionnaires.

•

The control programme did not meet our evaluation criteria in most communities studied.

•

Other measures should be considered to improve Echinococcus spp. control in Xinjiang.

The Xinjiang Uyghur Autonomous Region in northwest China is one of the world's most important foci for cystic echinococcosis. Domestic dogs are the main source for human infection, and previous studies in Xinjiang have found a canine Echinococcus spp. coproELISA prevalence of between 36% and 41%. In 2010 the Chinese National Echinococcosis Control Programme was implemented in Xinjiang, and includes regular dosing of domestic dogs with praziquantel. Six communities in Hobukesar County, northwest Xinjiang were assessed in relation to the impact of this control programme through dog necropsies, dog Echinococcus spp. coproantigen surveys based on Lot Quality Assurance Sampling (LQAS) and dog owner questionnaires. We found that 42.1% of necropsied dogs were infected with Echinococcus granulosus, and coproELISA prevalences were between 15% and 70% in the communities. Although approximately half of all dog owners reported dosing their dogs within the 12 months prior to sampling, coproELISA prevalence remained high. Regular praziquantel dosing of owned dogs in remote and semi-nomadic communities such as those in Hobukesar County is logistically very difficult and additional measures should be considered to reduce canine echinococcosis.

Epidemiology and control of echinococcosis in central Asia, with particular reference to the People's Republic of China

At least 270 million people (58% of the total population) are at risk of cystic echinococcosis (CE) in Central Asia including areas of Mongolia, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, Uzbekistan, Afghanistan, Iran, Pakistan and western China. The annual surgical incidence rate in Uzbekistan and Tadjikistan has been estimated to be as high as 25-27 cases/100,000 with the highest prevalence reaching 10% (range from 0.8 to 11.9%) in some Tibetan communities in western China. Echinococcus transmission in the region is largely associated with social factors including limited community knowledge of echinococcosis, small-scale household animal production, home killing of livestock, and the feeding of dogs with uncooked offal. Alveolar echinococcosis (AE) is also endemic in Central Asia and is recognized as a major problem in some Tibetan communities with up to 6% of villagers infected in some villages. In western China, 5-30% of the population are seropositive against E. granulosus antigens, indicating that a large number of individuals have been exposed to the parasite. Although echinococcosis control programs have been initiated in some countries in Central Asia, control efforts are generally fragmented and uncoordinated. Monthly deworming of dogs with praziquantel (PZQ), as a key measure to control the Echinococcus parasites, has been used in western China. However, the approach has proven difficult in local semi-nomadic communities. Additional control measures including health education, domestic livestock animal treatment/vaccination and dog vaccination are needed in CE-endemic areas to accelerate progress.

Cystic echinococcoses in Mongolia: molecular identification, serology and risk factors

Background

Cystic echinococcosis (CE) is a globally distributed cestode zoonosis that causes hepatic cysts. Although Echinococcus granulosus sensu stricto (s.s.) is the major causative agent of CE worldwide, recent molecular epidemiological studies have revealed that E. canadensis is common in countries where camels are present. One such country is Mongolia.

Methodology/Principal Findings

Forty-three human hepatic CE cases that were confirmed histopathologically at the National Center of Pathology (NCP) in Ulaanbaatar (UB) were identified by analysis of mitochondrial cox 1 gene as being caused by either E. canadensis (n = 31, 72.1%) or E. granulosus s.s. (n = 12, 27.9%). The majority of the E. canadensis cases were strain G6/7 (29/31, 93.5%). Twenty three haplotypes were identified. Sixteen of 39 CE cases with data on age, sex and province of residence were citizens of UB (41.0%), with 13 of the 16 cases from UB caused by E. canadensis (G6/7) (81.3%). Among these 13 cases, nine were children (69.2%). All pediatric cases (n  =  18) were due to E. canadensis with 17 of the 18 cases (94.4%) due to strain G6/7. Serum samples were available for 31 of the 43 CE cases, with 22 (71.0%) samples positive by ELISA to recombinant Antigen B8/1 (rAgB). Nine of 10 CE cases caused by E. granulosus s.s. (90.0%) and 13 of 20 CE cases by E. canadensis (G6/7) (65.0%) were seropositive. The one CE case caused by E. canadensis (G10) was seronegative. CE cases caused by E. granulosus s.s. showed higher absorbance values (median value 1.131) than those caused by E. canadensis (G6/7) (median value 0.106) (p  =  0.0137).

Conclusion/Significance

The main species/strains in the study population were E. canadenis and E. granulossus s.s. with E. canadensis the predominant species identified in children. The reason why E. canadensis appears to be so common in children is unknown.

Cystic echinococcosis (CE) is a parasitic zoonosis with a cosmopolitan distribution. Molecular analysis was carried out on 43 hepatic CE cysts from 43 cases confirmed histopathologically at the NCP, Mongolia. Molecular analysis revealed two species, Echinococcus canadensis and Echinococcus granulosus s.s. Twenty three haplotypes of the cox1 gene were identified. All pediatric cases (n = 18) were by E. canadensis. Sixteen of 39 CE cases with data on age, sex and province of residence were from UB (41.0%), and 13 of these 16 cases were caused by E. canadensis (81.3%). Among the 13 cases from UB, nine were children (69.2%). A total of 31 serum samples from these 43 cases were analyzed for antibody response to rAgB with 22 (71.0%) samples positive by ELISA to rAgB. Thirteen of 20 E. canadensis (G6/7) (65%) and nine of 10 E. granulosus s.s. (90%) were seropositive. CE cases by E. granulosus s.s. showed a higher absorbance value than cases by E. canadensis (p  =  0.0137). This is the first study to evaluate age distribution of and antibody responses to rAgB in CE cases caused by the two species in Mongolia. It remains unknown why E. canadensis appears to be more common in pediatric cases.

Primary intracranial and spinal hydatidosis: a retrospective study of 21 cases

OBJECTIVE

To analyse the epidemiological characteristics, clinical symptoms, radiological aspects, treatments, and outcomes of primary central nervous system (CNS) hydatidosis and compare our results with those observed for secondary intracranial hydatidosis.

PATIENTS AND METHODS

We retrospectively reviewed 21 cases of primary CNS hydatid cysts operated on at the First Affiliated Hospital of Xinjiang Medical University between 1996 and 2010.

RESULTS

Of the 21 primary cases, the vast majority were intracranial hydatidosis patients (20 cases, 95·24%). Only one patient had spinal hydatidosis. Unlike previously published reports, we found that intracranial hydatid cysts were more common in adults (80·96%) than in children (19·04%), with a slight male predominance (M/F = 1·1). All symptoms, including vomiting, nausea, and focal neurological signs, resulted from the increased intracranial pressure, which was closely associated with the cyst location. For the spinal hydatidosis patient, the primary symptom of back pain was indicative of spinal cord compression syndrome. All cysts in the 21 primary cases were pathologically similar. The recurrence percentage was 28% over 12 years. Two patients with multiple intracranial hydatid cysts died due to foramen magnum herniation.

CONCLUSION

Despite imaging and therapeutic advances, CNS hydatidosis remains difficult to treat, and severe complications and the high incidence of recurrence result in unsatisfactory outcomes.

Canine echinococcosis: global epidemiology and genotypic diversity

Canine echinococcosis is a potential zoonotic infection caused by the adult form of several cestode species belonging to the genus Echinococcus, of which E. granulosus sensu lato and E. multilocularis are the most epidemiologically relevant. Dogs infected with E. granulosus and E. multilocularis are widely regarded as the main source of infection for human cystic and alveolar echinococcosis, diseases that cause substantial morbidity and socio-economic burden in several regions of the world. Following our previous review on the global situation of cystic echinococcosis in livestock species (Cardona and Carmena. Vet. Parasitol. 2013;192:10-32), we summarize here current knowledge on the global epidemiology, geographical distribution and molecular diversity of Echinococcus spp. infection in dogs. We address relevant topics including the implications of the increasing urbanization of wildlife species such as foxes, coyotes, and dingoes in the establishment of urban cycles of Echinococcus spp., or the rising concerns regarding the role of unsupervised translocation of infected dogs in spreading the infection to Echinococcus-free areas. The involvement of wildlife species as natural reservoirs of disease to domestic animals and humans and the epidemiological significance of the sympatric occurrence of different Echinococcus species in the same geographical region are also debated. Data presented are expected to be useful for policy makers, educational and health authorities responsible for designing and implementing effective measures for disease control and prevention.

A systematic review of the literature on cystic echinococcosis frequency worldwide and its associated clinical manifestations

A systematic literature review of cystic echinoccocosis (CE) frequency and symptoms was conducted. Studies without denominators, original data, or using one serological test were excluded. Random-effect log-binomial models were run for CE frequency and proportion of reported symptoms where appropriate. A total of 45 and 25 articles on CE frequency and symptoms met all inclusion criteria. Prevalence of CE ranged from 1% to 7% in community-based studies and incidence rates ranged from 0 to 32 cases per 100,000 in hospital-based studies. The CE prevalence was higher in females (Prevalence Proportion Ratio: 1.35 [95% Bayesian Credible Interval: 1.16-1.53]) and increased with age. The most common manifestations of hepatic and pulmonary CE were abdominal pain (57.3% [95% confidence interval [CI]: 37.3-76.1%]) and cough (51.3% [95% CI: 35.7-66.7%]), respectively. The results are limited by the small number of unbiased studies. Nonetheless, the age/gender prevalence differences could be used to inform future models of CE burden.

Domestic dogs in a fragmented landscape in the Brazilian Atlantic Forest: abundance, habitat use and caring by owners

This study aimed at estimating the population size and attitudes of residents towards caring for domestic dogs, through questionnaire surveys, as well as the frequency of these animals in different habitats (anthropic and forest patch), using scent stations. The study was conducted in a severely fragmented area of the Brazilian Atlantic Forest. A large number of unrestricted dogs was recorded, averaging 6.2 ind/km². These dogs have owners and are regularly fed. Dog records decreased from the anthropogenic matrix to the forest patch edge, which suggests that dogs act as an edge effect on forest patches. Encounters between domestic dog and wild animals can still be frequent in severely fragmented landscapes, mainly at the forest edges. However the fact that most dogs have an owner and are more frequent in the anthropic habitat suggests that their putative effects are less severe than expected for a carnivore of such abundance, but the reinforcement of responsible ownership is needed to further ameliorate such effects.

Treatment of liver hydatidosis: How to treat an asymptomatic carrier?

Liver hydatidosis is the most common clinical presentation of cystic echinococcosis (CE). Ultrasonographic mass surveys have demonstrated the true prevalence, including the asymptomatic characteristic of the majority of cases, providing new insight into the natural history of the disease. This raises the question of whether to treat or not to treat these patients, due to the high and unsuspected prevalence of CE. The high rate of liver/lung frequencies of cyst localization, the autopsy findings, and the involution of cysts demonstrated in long time follow-up of asymptomatic carriers contribute to this discussion. The decision to treat an asymptomatic patient by surgery, albendazole, or puncture aspiration injection and reaspiration or to wait and watch, is based on conflicting reports in the literature, the lack of complications in untreated patients over time, and the spontaneous disappearance and involution of cysts. All these points contribute to difficulties of individual clinical decisions. The patients should be informed of the reasons and the risks of watchful/waiting without treatment, the possibility of complications, and the risks of the other options. As more information on the natural history of liver hydatidosis is acquired, selection of the best treatment will be come easier. Without this knowledge it would be very difficult to establish definitive rules of treatment. At present, it is possible to manage these patients over time and to wait for the best moment for treatment. Follow-up studies must be conducted to achieve this objective.

Recent advances in the microbial safety of fresh fruits and vegetables

Foodborne illness outbreaks linked to fresh produce are becoming more frequent and widespread. High impact outbreaks, such as that associated with spinach contaminated with Escherichia coli O157:H7, resulted in almost 200 cases of foodborne illness across North America and >$300 m market losses. Over the last decade there has been intensive research into gaining an understanding on the interactions of human pathogens with plants and how microbiological safety of fresh produce can be improved. The following review will provide an update on the food safety issues linked to fresh produce. An overview of recent foodborne illness outbreaks linked to fresh produce. The types of human pathogens encountered will be described and how they can be transferred from their normal animal or human host to fresh produce. The interaction of human pathogens with growing plants will be discussed, in addition to novel intervention methods to enhance the microbiological safety of fresh produce.

A province-based study using sampling method to investigate the prevalence of cystic echinococcosis among primary school children in Manisa, Turkey

A province-based field study using a portable ultrasound scanner (US) was performed for the first time using sampling method to investigate the prevalence of cystic echinococcosis (CE) in primary school children in Manisa, Turkey. A total of 6093 children from 37 primary schools was selected as the representative sample of the total number of 166,766 primary school children, and examined by the US. Prevalence was found to be 0.15%, as nine children were diagnosed with CE, seven new and two previously operated. A questionnaire applied to the children revealed no significant relationship between the risk factors and the infection (P>0.05). In conclusion, it would be advisable to repeat the study at the same schools in eight years' time, in order to evaluate the efficacy of the control programs, since nearly all students involved in this study will have graduated by then. Besides, it is recommended to choose a sampling group to find the prevalence of an infection in a defined region.

Intestinal protozoan infections and echinococcosis in the inhabitants of Dornod and Selenge, Mongolia (2003)

The status of intestinal parasitic infections and seroprevalence of cystic echinococcosis in the inhabitants in Dornod and Selenge, Mongolia, was observed with stool and serum samples from 165 and 683 residents from August 9 to August 15, 2003. A total of 10 inhabitants (6.1%) were found to be infected with protozoan cysts or oocysts by stool examinations; 7, 1 and 2 cases with Entamoeba coli, Giardia lamblia and Cryptosporidium parvum, respectively. A total of 62 people (9.1%) revealed significantly high levels of specific antibodies against Echinococcus granulosus by enzyme-linked immunosorbent assay (ELISA). The surveyed areas are rural areas and the sanitized tab water is not available. There is a possibility of endemic transmission of water-borne protozoan diseases in these areas. The clinical echinococcosis is needed to be searched from the seropositive inhabitants.

Hydatid cysts: does every picture tell a story?

Ultrasound imaging is an effective aid to the detection of abdominal cystic echinococcosis. Recently, the images produced have provided more information than just a diagnosis. Different cyst morphologies have been classified into types, and such classifications can be considered to represent a natural history of cyst development. Understanding how cyst structures alter with time is crucial to evaluating the effectiveness of different treatment regimes and to understanding natural degeneration of cysts that can occur. However, the developmental events seen in ultrasound need to be matched more closely to immunological and cellular events if we are to have a fuller appreciation of disease progression and regression. At a community level, the relative proportions of cyst types could also provide epidemiological information on disease transmission.

Genotyping of human cystic echinococcosis in Xinjiang, PR China

The Xinjiang Uygur Autonomous Region, multi-ethnic province in northwestern China, is one of the most important foci of human cystic echinococcosis (CE) in the world. Two Echinococcus granulosus genotypes (G1 and G6) are known to infect the intermediate hosts in this area but, to date, the source of the human infection remains unclear. The current study aimed to genetically analyse 67 hydatid cysts removed from 47 CE patients for which epidemiological, clinical and serological data were also recorded. Mitochondrial cox 1 gene sequencing suggested that the E. granulosus G1 genotype is the major source of infection (45/47 CE patients). Nevertheless, for the first time in China, 2 patients were found with hydatid cysts of the G6 genotype. In addition, 45 E. granulosus gravid tapeworms, isolated from 13 dogs, were genotyped. The majority of adult worms (42/45) exhibited the G1 genotype, whereas 3 adult tapeworms with the G6 genotype were found in one dog, that also harboured E. granulosus tapeworms of the G1 genotype. This sympatric occurrence of G1 and G6 genotypes of E. granulosus, not only in the same area but also in the same definitive host, raises the interesting question of putative genetic recombination between these E. granulosus genotypes.