Distinguishing Echinococcus granulosus sensu stricto genotypes G1 and G3 with confidence: A practical guide

Molecular phylogenetic analysis of Echinococcus granulosus sensu lato infecting sheep in Italy

Cystic Echinococcosis (CE), caused by the larval form of Echinococcus granulosus sensu lato, is a neglected zoonosis still threatening public health worldwide. In Italy different epidemiological scenarios were reported depending on the geographical area and associated socio-economic activities. Although in northern Italy the occurrence of E. granulosus is considered sporadic, in the southern regions and, particularly in Sardinia, CE prevalence reaches high levels. We analysed CE cysts collected from infected sheep from various areas of mainland Italy and the Sardinia island, with the main objective to investigate intergenotypic and intragenotypic variations at national level. CE cysts were collected from slaughtered sheep following post mortem inspection at local abattoirs. Total genomic DNA was extracted and amplification and sequencing of the partial mitochondrial genes nad5 and cox1 were performed. A Bayesian phylogenetic tree was estimated on a nad5 dataset (n = 260) composed of E. granulosus samples from this study (n = 126) and all the nad5 haplotypes available in GenBank (n = 134). In addition, haplotype network, diversity and neutrality analysis were performed on nad5 and cox1 sequences of Italian origin obtained in this study. E. granulosus sensu stricto (s.s.) was found to be the only Echinococcus species infecting sheep in Italy, mainly represented by G1 genotype (76 %) and, to a lower extent, by G3 genotype (24 %). Phylogenetic analyses revealed 40 nad5 and 33 cox 1 haplotypes, and the presence of two founder haplotypes, belonging to G1 and G3 genotype, showing 100 % similarity with DNA sequences from different geographic regions. The lack of geographical segregation, high haplotype and low nucleotide diversity coupled with significant negative values of Tajima's D and Fu's Fs observed in this study indicated high genetic variation and demographic expansion of E. granulosus s.s. in Italy.

Molecular discrimination of G1 and G3 genotypes of Echinococcus granulosus sensu stricto obtained from human, cattle, and sheep using the mitochondrial NADH dehydrogenase subunit 5 marker

Cystic echinococcosis (CE) is a common zoonotic disease caused by the larval form of Echinococcus granulosus sensu lato. This study determined the genotype and haplotype differences using the NADH dehydrogenase subunit 5 gene in hydatid cyst samples. Human (n = 12), cattle (n = 28), and sheep (n = 31) hydatid cyst isolates were included. Seventy-one genomic DNA samples were successfully extracted, and a 759 bp mitochondrial NADH dehydrogenase subunit 5 gene fragment was amplified by PCR. Following the sequence analysis, E. granulosus sensu stricto isolates were identified as G1 (n = 61) and G3 (n = 10). A total of 23 haplotypes were obtained from the 71 E. granulosus s.s. G1 and G3 samples. The main haplotype was Hap01 (60.56 %), which consisted of the G1 genotype. The second largest haplotype was Hap04, which consisted entirely of the G3 genotype. Hap14 acted as a bridge between the G1 and G3 genotypes. This study identifies G1 as the dominant genotype in humans and farm animals in Turkey. High haplotype and nucleotide diversity in genotypes were observed. Additionally, this is the first report on the phylogeography and gene flow models of the E. granulosus s.s. population in Turkey using the NADH dehydrogenase subunit 5 gene, the best marker distinguishing between G1 and G3 genotypes.

Understanding the role of pigs in the transmission of zoonotic Echinococcus ortleppi in Haryana, India

The etiological agents of zoonotic cystic echinococcosis comprise the Echinococcus granulosus sensu lato (s.l.) species complex. The present study was aimed at investigating the zoonotic genotypes of Echinococcus granulosus s.l. circulating in the pig population of Haryana, India. Out of 253 slaughtered pigs screened, 5 showed the presence of hydatid cysts. The amplification of the partial mitochondrial NADH dehydrogenase subunit 1 (nad1) gene for the molecular confirmation and phylogenetics of the retrieved metacestodes (n = 2) revealed the presence of E. ortleppi. The sequences generated herein exhibited 99.80% homology to the GenBank archived E. ortleppi sequences. Cladistics targeting genetic diversity and haplotype network analysis involved 37 E. granulosus s.l. GenBank archived sequences from India corresponding to different hosts (large and small ruminants and humans) along with the sequences (n = 2) generated in the present study. Overall, 14 haplotypes with high haplotype (0.780 ± 0.059) and low nucleotide (0.033 ± 0.010) diversities were recorded for the overall data set, which evinced a population expansion. The median-joining haplotype network revealed a stellate shape of E. granulosus sensu stricto (s.s.) sequences, which was indicative of rapid population expansion. High genetic differentiation (FST = 0.840 - 0.983) and low gene flow (Nm = 0.003 - 0.047) were recorded between the pig intermediate hosts infected with E. ortleppi and other hosts infected with E. granulosus s.s. The findings are of paramount significance for the formulation of effective control strategies considering the public health and economic impact of cystic echinococcosis.

Cystic echinococcosis in cattle and sheep caused by Echinococcus granulosus sensu stricto genotypes G1 and G3 in the USA

BACKGROUND

Endemic domestic dog-ruminant cycles and human cystic echinococcosis caused by Echinococcus granulosus have been sporadically reported in the United States. However, there is a paucity of molecular data describing the genotypes and haplotypes of this important cestode in domestic ruminant hosts.

METHODS

Ninety-four cysts from the lungs and/or livers of slaughtered beef cattle (76 samples), dairy cows (five samples) and sheep (13 samples) were collected from abattoirs in four states of the USA. Samples were genotyped at two mitochondrial loci, cox1 and nad5. Sequences were used to determine species, genotypes and haplotypes using median joining networks and Bayesian phylogenetic analyses. Cyst fertility was assessed in hematoxylin and eosin-stained sections. Additionally, previously reported autochthonous E. granulosus infections in the USA in various hosts were mapped.

RESULTS

Based on cox1 sequences obtained from 94 cysts, 89 (94.7%) were identified as E. granulosus G1/G3, while five (5.3%) were Taenia hydatigena. Taenia hydatigena were only isolated from sheep. Based on nad5 sequences obtained from 89 hydatid cysts, 96.6% and 3.4% belonged to E. granulosus sensu stricto genotypes G1 and G3 respectively. Two haplotypes were found among E. granulosus cox1 sequences, neither of which was geographically unique. Six haplotypes were found among nad5 sequences in genotype G1, of which five were novel, while one haplotype was found in genotype G3. In the concatenated cox1-nad5 dataset, seven haplotypes were identified, of which six were geographically unique. All cysts from cattle were non-fertile. Four cysts from sheep were fertile.

CONCLUSIONS

All genotyped samples belonged to E. granulosus s.s. This is the first study to our knowledge to confirm the presence of genotypes G1 and G3 in domestic cattle and sheep intermediate hosts in the USA and provide data for future diagnostic and epidemiological studies. Sequences have been deposited in GenBank (cox1 sequences: OR398494-OR398496, nad5 sequences: OR400695-OR400702).

Cladistics of Echinococcus granulosus Sensu Stricto Genotypes Infecting the Slaughtered Pigs

PURPOSE

Echinococcus granulosus sensu stricto (s. s.) consists of the most widespread genotypes (G1, G3) implicated in human cystic echinococcosis worldwide. The present study aimed to evaluate the role of pigs in the transmission dynamics of E. granulosus s. s. genotypes, including the phylogenetics, evolutionary divergence and haplotype network analyses of north Indian pig isolates along with GenBank™ archived sequences.

METHODS

In totality, 223 slaughtered pigs were thoroughly screened for the presence of hydatid cysts. The amplification of the partial mitochondrial cytochrome C oxidase subunit 1 gene was performed for the molecular confirmation and phylogenetics of the retrieved metacestodes.

RESULTS

The molecularly confirmed and sequenced present study isolates (n = 2) clustered with the E. granulosus genotype G3. The very low evolutionary divergence values (< 0.0027) of the present study isolates with E. ganulosus genotype G3 indicated the absence of diverged lineages. The significantly negative values of Tajima's D (- 2.598) and Fu and Li's D (- 4.054) of the overall dataset and for the Asian sequences signified an expansion of population size. The overall dataset exhibited low nucleotide (0.067 ± 0.055) and high haplotype (0.574 ± 0.015) diversities, also alluding to demographic expansion. The haplotype network showed that the pig isolates from South America and Europe constituted the predominant haplotype, Hap_2 along with Hap_3 and Hap_6, primarily associated to E. granulosus genotype G1; whereas, the Indian isolates formed different haplotypes (Hap_1 and Hap_5) belonging to genotype G3.

CONCLUSIONS

The present study highlighted the important role of pigs in the transmission of E. granulosus s. s., which is of paramount significance given the public health and economic impact of cystic echinococcosis.

Primary cerebral cystic echinococcosis in a child from Roman countryside: Source attribution and scoping review of cases from the literature

BACKGROUND

Human cystic echinococcosis (CE) is a zoonotic parasitic infection caused by the larval stage of the species belonging to the Echinococcus granulosus sensu lato (s.l.) complex. Parasitic cysts causing human CE are mainly localized in the liver and in the lungs. In a smaller number of cases, larvae may establish in any organ or tissue, including the central nervous system (CNS). Cerebral CE (CCE) is rare but poses serious clinical challenges.

METHODS

This study presents a case of CCE in a child living in the countryside near Rome (Italy), along with a comparative molecular analysis of the isolated cyst specimens from the patient and sheep of local farms. We also systematically searched the literature to summarize the most relevant epidemiological and clinical aspects of this uncommon localization.

FINDINGS

The comparative molecular analysis confirmed that the infection was caused by E. granulosus sensu stricto (s.s.) (G3 genotype), and most likely acquired in the family farm. The literature search identified 2,238 cases of CCE. In 80.51% of cases, brain was the only localization and single CCE cysts were present in 84.07% of cases. Mean patients' age was 20 years and 70.46% were children. Cyst rupture was reported in 12.96% and recurrence of CCE after treatment in 9.61% of cases. Permanent disability was reported in 7.86% of cases, while death occurred in 6.21%. In case series reporting all CE localization, CCE represented 1.5% of all CE cases. In the few reports that identified at molecular level the CCE cyst, E. granulosus s.s. was found in 40% and E. canadensis in 60% of cases.

CONCLUSIONS

We report a rare case of CCE and evidenced the probable local origin of infection. The proportions of CE cases with uncommon localizations and with high impact on patients' lives have been globally neglected and should be included in the computation of the global burden of CE.

Tapeworms detected in wolf populations in Central Italy (Umbria and Marche regions): A long-term study

Tapeworms are trophically-transmitted and multi-host parasites with a complex indirect life cycle, strictly depending on predator-prey interactions. Their presence in a free-living population, mainly definitive hosts, is arduous to study due to the complexity of collecting fecal samples. However, epidemiological studies on their frequency are crucial from a public health perspective, providing information on food habits and prey selection of predators. The present study aims to update the frequency of tapeworms detected in stool samples by molecular analysis in Italian wolf populations of Umbria and Marche regions collected from 2014 to 2022. Tapeworm's total frequency was 43.2%. In detail, Taenia serialis was detected in 27 samples (21.6%), T. hydatigena in 22 (17.6%), and Mesocestoides corti (syn. M. vogae) in 2 (1.6%). Three samples were identified as M. litteratus and E. granulosus s.s. (G3) and T. pisiformis, with a proportion of 0.8%, respectively. The low frequency of E. granulosus in a hyperendemic area is discussed. The results show for the first time a high frequency of Taenia serialis not comparable to other Italian studies conducted on wild Carnivora; thus, a new ecological niche is conceivable. These findings suggest a plausible wolf-roe deer cycle for T. serialisin the investigated area.

First isolation of Echinococcus granulosus sensu lato genotype 7 in the archipelago of Cape Verde

There are no scientific data available on the occurrence of the Echinococcus granulosus sensu lato (s.l.) cluster in definitive hosts (domestic dogs), intermediate hosts (domestic livestock) nor humans in Cape Verde. In this pilot study, environmental dog fecal samples (n = 369) were collected around food markets, official slaughterhouses, as well as home and small business slaughter spots in 8 of the 9 inhabited islands from the Cape Verde archipelago, between June 2021 and March 2022. Additionally, during the same period, 40 cysts and tissue lesions were opportunistically collected from 5 islands, from locally slaughtered cattle (n = 7), goats (n = 2), sheep (n = 1) and pigs (n = 26). Genetic characterization by a multiplex polymerase chain reaction assay targeting the 12S rRNA gene confirmed the presence of E. granulosus s.l. in fecal and tissue material. In total, 17 cyst samples from Santiago (n = 9), Sal (n = 7) and São Vicente (n = 1) and 8 G6/G7-positive dog fecal samples from Santiago (n = 4) and Sal (n = 4) were identified as E. granulosus s.l. G7 by sequence analysis (nad2, nad5 and nad1 genes). This study discloses the transmission of E. granulosus s.l. G7, in pig, cattle and dog in Cape Verde.

Genetic Characterization of Echinococcus granulosus sensu stricto Isolated from Human Cysts from Sardinia, Italy

This study involved 20 patients affected by cystic echinococcosis (CE) who were referred to different hospitals of Sardinia (Italy) from 2017 to 2022. By means of a multidisciplinary approach, diagnosis was confirmed for CE in 18 patients and for different aetiologies in two subjects. Moreover, serology was positive for 15 subjects. Since multiple CE cysts were found in five patients, a total of 27 lesions were collected; however, only one for each patient was investigated for genetic characterization of E. granulosus s.s. DNA isolates. Our results included 15 fertile cysts that underwent DNA extraction and amplification by three different PCRs targeting nuclear (calreticulin) and mitochondrial genes (cox1 and nad5). DNA was sequenced, and by neighbour-joining phylogenetic trees we determined 10 G1 and five G3 genotypes previously reported in Sardinia. These sequences were used to construct a network, along with those circulating in Mediterranean areas. The haplotype network calculated on cox1 evidenced seven different haplotypes of the 15 isolates, with SAR2 the most represented, carried by seven cysts, and SAR17 never described in the Mediterranean area. Meanwhile, the nad5 sequences showed the most common haplotype as nd5SAR7, as well as two new haplotypes not previously described, nd5SAR13, isolated from a Sardinian patient, and nd5SAR14, isolated from a Romanian patient.

Revealing novel cytb and nad5 genes-based population diversity and benzimidazole resistance in Echinococcus granulosus of bovine origin

Cystic echinococcosis (CE) is a neglected zoonotic disease caused by Echinococcus granulosus (sensu stricto). The parasite affects a wide range of livestock and wild animals. In this study, the population diversity of the Echinococcus species was investigated based on mitochondrial cytochrome b (cytb) and NADH dehydrogenase subunit 5 (nad5) genes. In addition to this, β-tubulin gene isoforms of Echinococcus granulosus were amplified to determine the resistance against benzimidazoles. For this purpose, 40 cyst samples from cattle (n = 20) and buffaloes (n = 20) were collected from the main abattoir of Sialkot. DNA extraction was performed using Qiagen Blood and Tissue Kits. Amplification was performed through PCR. Each amplicon was confirmed by GelRed™ stained agarose gel (2%). Samples were sequenced in a DNA analyzer and viewed for any misread nucleotide by using MEGA (v.11). Corrections in nucleotide sequence and multiple sequence alignment were made through the same software. NCBI-BLAST was used for sample specific sequences to identify them as belonging to a particular species. Diversity indices were estimated using DnaSP (v.6) while phylogenetic analysis was inferred using the Bayesian method using MrBayes (v.1.1). β-tubulin gene isoforms sequence analysis was performed to find out the candidate gene causing benzimidazole resistance. All 40 isolates were found positive for E. granulosus. BLAST-based searches of sequences of each isolate for each gene (nad5 and cytb) confirmed their maximum similarity with the G1 genotype. Overall, high haplotype diversity (Hd nad5 = 1.00; Hd cytb = 0.833) and low nucleotide diversity (π nad5 = 0.00560; π = cytb = 0.00763) was identified based on diversity indices. For both the genes, non-significant values of Tajima's D (nad5 = -0.81734; cytb = -0.80861) and Fu's Fs (nad5 = -1.012; cytb = 0.731) indicate recent population expansion. Bayesian phylogeny-based results of nad5 and cytb sequences confirmed their genotypic status as distinct from other Echinococcus species. This study shed light on the status of benzimidazole resistance in Echinococcus granulosus for the very first time from Pakistan. The findings of this study will significantly add in the information available on genetic diversity of Echinoccous granulosus based on cytb and nad5 genes sequences.

First report of Echinococcus ortleppi and E. canadensis (genotype G6) from southern Punjab, Pakistan and a global overview on genetic structure and host adaptation of E. ortleppi

Cystic echinococcosis (CE), caused by Echinococcus granulosus sensu lato, is a neglected tropical disease known mainly for its zoonotic nature. CE is endemic to Pakistan, however, the disease is not given due consideration and millions of people remain at health risk. This study was undertaken to assess the species and genotypes of E. granulosus sensu lato in sheep, buffaloes and cattle, brought to slaughterhouses of two major cities (Multan and Bahawalpur) of south Punjab, Pakistan. A total of 26 hydatid cyst specimens were characterized through complete cox1 mitochondrial gene (1609 bp) sequencing. Species and genotypes of E. granulosus sensu lato discovered in the southern Punjab consisted of E. granulosus sensu stricto (n =21), E. ortleppi (n=4) and E. canadensis G6 genotype (n=1). Of E. granulosus s.s. isolates, the genotype G3 was predominantly involved in causing infections to the livestock of this region. Since all of these species are zoonotic, wide and effective surveillance studies are required to ascertain the risks to human population in Pakistan. Additionally, a global overview on cox1 phylogenetic structure of E. ortleppi was carried out. Despite the widespread occurrence, the species is mostly limited to the southern hemisphere. The highest burden has been reported in the South America (62.15%) and Africa (28.44%) and by far the most common host is cattle, accounting for >90% of cases.

Molecular Screening of Echinococcus spp. and Other Cestodes in Wild Carnivores from Central Italy

Tapeworm infections are among the most relevant parasitic diseases in humans and animals. Tapeworms from the Genus Echinococcus are particularly important as they can cause cystic or alveolar echinococcosis. A molecular screening was performed on 279 fecal samples collected from carcasses of wild carnivores from Central Italy using PCR targeting diagnostic fragments of nad1, rrnS, and nad5 genes. Samples positive for either Taenia spp. or Echinococcus granulosus were sequenced to taxonomically identify the parasitic DNA. Of the 279 samples, 134 (48.0%) gave positive results in the multiplex PCR. Only one (0.4%) sample from an Apennine wolf tested positive for Echinococcus granulosus sensu stricto (genotype G3), whereas no sample tested positive for E. multilocularis. The most frequently detected tapeworms were: Mesocestoides corti (syn M. vogae) (12.9%), M. litteratus (10.8%), Taenia serialis (9.3%), and T. hydatigena (6.5%), other tapeworms were rarely detected. The results suggest that Echinococcus infections in Central Italy do not seem to be sustained by sylvatic cycles, confirming the absence of E. multilocularis in Central Italy. The survey corroborates, yet again, the importance of passive surveillance of wild animals that can serve as reservoirs for zoonotic pathogens, especially on wild canids that in other areas are strongly implicated in the transmission of E. granulosus and E. multilocularis.

Cystic echinococcosis in Iceland: a brief history and genetic analysis of a 46-year-old Echinococcus isolate collected prior to the eradication of this zoonotic disease

Cystic echinococcosis (CE) is considered the most severe parasitic disease that ever affected the human population in Iceland. Before the start of eradication campaign in the 1860s, Iceland was a country with very high prevalence of human CE, with approximately every fifth person infected. Eradication of CE from Iceland by 1979 was a huge success story and served as a leading example for other countries on how to combat such a severe One Health problem. However, there is no genetic information on Echinococcus parasites before eradication. Here, we reveal the genetic identity for one of the last Echinococcus isolates in Iceland, obtained from a sheep 46 years ago (1977). We sequenced a large portion of the mitochondrial genome (8141 bp) and identified the isolate as Echinococcus granulosus sensu stricto genotype G1. As G1 is known to be highly infective genotype to humans, it may partly explain why such a large proportion of human population in Iceland was infected at a time . The study demonstrates that decades-old samples hold significant potential to uncover genetic identities of parasites in the past.

Introductory Chapter: Changes in Eco-System Change Echinococci - “One Health Concept” against Echinococci

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

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

Genetic characterization of human echinococcosis in Southern Punjab, Pakistan

Introduction

Echinococcosis is a neglected tropical zoonotic infection that affects both the human and livestock populations. In Pakistan, the infection is long-standing, but data on its molecular epidemiology and genotypic characterization in the southern Punjab region are limited. The aim of the current study was the molecular characterization of human echinococcosis in southern Punjab, Pakistan.

Methods

Echinococcal cysts were obtained from a total of 28 surgically treated patients. Patients' demographic characteristics were also recorded. The cyst samples were subjected to further processing to isolate DNA in order to probe the Nad1 and Cyt-b genes, followed by DNA sequencing and phylogenetic analysis for genotypic identification.

Results

The majority of the echinococcal cysts were from male patients (60.7%). The liver was the most commonly infected organ (60.71%), followed by the lungs (25%), spleen (7.14%), and the mesentery (7.14%). Molecular and genotypic identification through sequencing and phylogenetic tree analysis showed that most of the cysts (24/28, 85.7%) were caused by the species Echinococcus granulosus sensu stricto (E. granulosus s.s.) (G1 and G3), followed by Echinococcus multilocularis (E. multilocularis) and Echinococcus canadensis (E. canadensis) (G6/G7) (3/28, 10.8%, and 1/28, 3.5%, respectively).

Conclusion

The current study concluded that the majority of human infections were caused by E. granulosus s.s., followed by the E. multilocularis and E. canadensis species (G6/G7). Genotypic characterization among both human and livestock populations is needed to explore the genetic diversity of echinococcosis.

Food-borne zoonotic echinococcosis: A review with special focus on epidemiology

Echinococcosis is a neglected, WHO-listed cyclozoonotic parasitic disease that is caused by a number of species belonging to the genus Echinococcus. This disease is widespread across the globe, resulting in heavy economic losses for farmers and cystic disease in aberrant human hosts. This review paper briefly discussed taxonomy, a brief history, the magnitude of economic losses, host spectrum and life cycle, risk factors, and clinical manifestations. Furthermore, the copro- and sero-ELISA-based prevalence of echinococcosis on different continents was summarized. Finally, the authors analyzed the frequency and use of molecular epidemiology in the taxonomy of Echinococcus species based on molecular markers. This review will serve as a quick reference to Echinococcus.

Genetic diversity of Echinococcus granulosus sensu lato from animals and humans in Bosnia and Herzegovina

BACKGROUND

Cystic echinococcosis (CE) is recognized as one of the most prevalent zoonotic diseases in Bosnia and Herzegovina. However, no systemic investigation of the genetic diversity of Echinococcus granulosus sensu lato circulating among animals and humans in the country has been performed to date.

METHODS

In this preliminary study, we analysed one cyst each from 36 sheep, 27 cattle, 27 pigs, 11 wild boars and 16 human patients for amplification and partial sequencing of the adenosine triphosphate 6 (atp6) and cytochrome c oxidase 1 (cox1) genes. The host species, fertility rate and organ cyst location were recorded for each subject involved in the study.

RESULTS

Overall, the atp6 gene was successfully amplified and sequenced from 110 samples, while 96 of the PCRs for cox1 were positive. Three zoonotic genotypes of E. granulosus sensu stricto (G1 and G3) and Echinococcus canadensis (G7) were identified in our isolates based on analyses of the atp6 gene. These genotypes were represented by 11 different genetic variants (haplotypes), six of which were identified for the first time in the present study.

CONCLUSIONS

This study demonstrates, for the first time, that CE in Bosnia and Herzegovina is predominantly caused by E. granulosus sensu stricto and E. canadensis clusters, which exhibited a lower genetic diversity compared to isolates from other European countries. Further molecular studies employing other mitochondrial and nuclear genes are required to better understand the transmission cycles of E. granulosus sensu stricto among intermediate and definitive hosts in the country.

'Fight the parasite': raising awareness of cystic echinococcosis in primary school children in endemic countries

BACKGROUND

Cystic echinococcosis (CE) is a widespread zoonosis and a significant economic concern and cause of morbidity in humans. A scarcity of education on the sources of CE infection and containment measures is considered to be a key factor responsible for persistent transmission within communities. Recently, edutainment approaches have captured the attention of health education (HE) professionals due to the benefits of integrating cognitive and emotional learning processes.

METHODS

A study was carried out in Sardinia, Italy, between 2020 and 2022, amid the SARS-Covid-19 pandemic. The project, designed to involve primary school children (via remote or face-to-face learning depending on the evolving Covid-19 containment measures) consisted of four distinct phases: (i) creation of material for school children and teachers focused on cystic echinococcosis; (ii) pre-intervention evaluation of CE knowledge (i.e. True False Don't Know [TFD] pre-intervention questionnaire based on CE-related knowledge and practices); (iii) edutainment activity (e.g. interactive lessons enhanced by the comic booklet and the "Fight the parasite" cartoon video, hands-on educational activities and drawing activities on CE); and (iv) post-intervention evaluation of CE knowledge (via TFD post-intervention questionnaire [same questionnaire as used for the pre-intervention assessment] on CE-related knowledge and practices) and on-site edutainment tour in primary schools taking part to the project.

RESULTS

The percentage of correct answers increased from 65% for the questionnaire administered pre-intervention to 87.9% for the same questionnaire administered post-intervention (χ² = 648.12, df = 1, P < 0.0001), while the percentage of uncertain answers (i.e. 'I don't know') decreased from 23% pre-intervention to 5% post-intervention (χ² = 603.44, df = 1, P < 0.0001). These differences indicate a significantly enhanced understanding of CE among participating school children after the intervention.

CONCLUSIONS

The results of the present survey indicate that the use of digital educational tools, the use of video animations as a model for science communication, as well as other participatory teaching methods, enabled children to retain key knowledge of the routes of CE transmission and ways to prevent it.

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

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

Genetic diversity of Echinococcus granulosus sensu lato in China: Epidemiological studies and systematic review

Cystic echinococcosis (CE) is a neglected tropical zoonosis caused by Echinococcus granulosus sensu lato (s.l.) and remains a major public health concern globally. Here, CE isolates (n = 3310) with clearly defined genotypes and geographical origins in China were retrieved through our epidemiological survey (2016-2020) and systematic review (1992-2020). Existing known genotypes of Echinococcus granulosus sensu lato (E. granulosus s.l.) except for G4 have been found in China, particularly on the Tibetan Plateau, where their genetic diversity is unique to that part of the world. According to the systematic review, genetic compositions of E. granulosus s.l. in China were as follows: E. granulosus (G1, G3), 98.3%; Echinococcus ortleppi (G5), 0.1%; Echinococcus intermedius (G6, G7), 1.4%; and Echinococcus canadensis (G8, G10), 0.2%. Specifically, G1 was responsible for 97.7% of infections and characterized by the broadest host ranges and geographic distributions. Our epidemiological results showed a relatively stable genetic composition of E. granulosus s.l. in sheep and yaks from three CE hyperendemic provinces (Xinjiang, Sichuan, Qinghai). A higher proportion of fertile cysts were found in sheep (287/406, 70.7%) than in yaks (28/184, 15.2%). During the past 29 years, 51 cox1 haplotypes of E. granulosus s.l. were endemic in China. The ancestral haplotype (Hap_2) remained the most common haplotype, 12 relatively common haplotypes were endemic and nine newly reported haplotypes were found during the survey. Overall, our results demonstrate that the compulsory immunization of sheep and the pilot EG95 vaccination campaign in yaks are well matched with the current genotypic situation. In addition to yaks, we advocate for more surveillance of CE isolates from pigs, cattle, goats and camels, since their roles in the transmission and reservation of E. granulosus s.l. have been largely ignored in China.

Molecular characterisation of Echinococcus granulosus sensu lato genotypes in dromedary camels from extreme Sahara of Algeria based on analysis of nad2 and nad5 genetic markers

Cystic echinococcosis is parasitic disease caused by the metacestodes belonging to the Echinococcus granulosus sensu lato (s.l.) species complex. Cystic echinococcosis is of considerable economic and public health importance. It is endemic in both livestock and humans in North African countries, including Algeria. The present study aimed to characterize E. granulosus s.l. genotypes in dromedary camels (Camelus dromedarius) from the extreme Sahara of Algeria, using recently developed mitochondrial genetic markers (NADH dehydrogenase subunit 2 and NADH dehydrogenase subunit 5) for reliable identification of different genotypes. A total of 75 Echinococcus cysts were collected from 49 dromedary camels, including 65 and 10 cysts from 45 and four camels originating from two slaughterhouses of Tindouf and Illizi provinces, respectively. E. granulosus sensu stricto (s.s.) G1 and G3 were identified in camels from both areas based on nad5 (649 bp) gene sequences, whereas E. granulosus s.l. G6 was identified in camels from Tindouf region based on concatenated nad5 and nad2 gene sequences (total 1336 bp). Identified samples clustered into 11 different haplotypes (ALG1-ALG11) including four haplotypes (ALG8-ALG11) for E. granulosus s.s. G1, one haplotype (ALG7) for E. granulosus s.s. G3, and six haplotypes (ALG1-ALG6) for E. granulosus s.l. G6. The present study provides valuable molecular data including genotyping and haplotypic variability on E. granulosus s.l. in dromedary camels from two regions in the extreme Sahara of Algeria. Future characterization of the G1, G3 and G6 samples based on sequencing of complete mitochondrial genomes would be of considerable significance for a more comprehensive understanding of molecular epidemiology of CE in Algeria.

Species and genotypes belonging to Echinococcus granulosus sensu lato complex causing human cystic echinococcosis in Europe (2000-2021): a systematic review

Background

This study aimed to fill a gap of knowledge by providing a quantitative measure of molecularly identified species and genotypes belonging to Echinococcus granulosussensu lato (s.l.) causing human cystic echinococcosis (CE) in Europe during the period 2000–2021. As these species and genotypes are characterized by genetic, animal host and geographical differences, studying the E. granulosuss.l. complex is epidemiologically relevant.

Methods

A systematic review (SR) was conducted on the basis of both scientific and grey literature considering primary studies between 2000 and 2021 in four databases. From a total of 1643 scientific papers, 51 records were included in the SR. The main inclusion criterion for this study was the molecular confirmation of E. granulosuss.l. at the genotype/species level as a causative agent of human CE cases in selected European countries.

Results

Relevant data were obtained from 29 out of 39 eligible European countries. This SR identified 599 human molecularly confirmed echinococcal cysts: 460 (76.8%) identified as E. granulosussensu stricto (s.s.), 130 (21.7%) as E. canadensis cluster (G6/7 and G10), 7 (1.2%) as E. ortleppi (G5), and 2 as E. vogeli (0.3%). Three geographical hotspots of human CE caused by different species of the E. granulosuss.l. complex were identified: (1) E. granulosuss.s. in Southern and South-eastern Europe (European-Mediterranean and Balkan countries); (2) E. canadensis (G6/7) in Central and Eastern Europe; (3) E. ortleppi in Central and Western Europe. This SR also identified data gaps that prevented a better definition of the geographical distribution of the Echinococcus granulosuss.l. species complex in Europe: western Balkan countries, part of Central Europe, and Baltic countries.

Conclusions

These results mandate longitudinal, multi-centre, intersectoral and transdisciplinary studies which consider both molecular and clinical epidemiology in animals and humans. Such studies would be valuable for a better understanding of the transmission of the E. granulosuss.l. species complex and their potential clinical impact on humans.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05197-8.

Insights into Human Cystic Echinococcosis in the Kurdistan Region, Iraq: Characteristics and Molecular Identification of Cysts

Cystic echinococcosis (CE) is a neglected worldwide distributed parasitic disease caused by the Echinococcusgranulosus sensu lato (s.l.) species complex. For a better understanding of the pathways of transmission of this parasite, clinical and molecular epidemiological studies are particularly needed from endemic areas where data are scant, such as in the Middle East. The study aimed to identify the characteristics, location, cyst stage and species/genotypes of E. granulosus s.l. complex in humans from the Kurdistan region, Iraq. To this aim, from June 2019 to February 2021, 64 echinococcal cysts were surgically removed from 62 patients in Azadi and Vajeen reference Hospitals at Duhok city, Duhok governorate (Kurdistan region, Iraq). The results confirmed the liver as the most common anatomical site of CE with 72.58% of the cases, followed by the lungs in 19.35%, while 66.13% of CE cases were females. The highest rate of infections occurred in the age class 21−30 (27.42%). High rates of CE were reported among patients living in rural areas and housewives, which were 54.84% and 43.55% of the CE patients, respectively. The fertility of echinococcal cysts was 82.81%, and the viability of fertile protoscoleces was 70.53%. Cysts were staged with ultrasound according to the WHO-IWGE classification as 32.8% CE1, 32.8% CE2, 7.8% CE3a, 9.4% CE3b, 15.6% CE4 and 1.6% CE5. Molecular analyses using mitochondrial NAD5 gene showed that all analyzed samples (n = 59) belonged to the genotypes G1 or G3 of E. granulosussensu stricto (s.s.), thus, confirming sheep−dog−human transmission in the Kurdistan region, Iraq. No statistically significant correlation was found between the genotypes G1−G3 of E. granulosus s.s. and variables, such as the fertility, location and cyst stage classification. Based on the present findings, it is necessary to implement monitoring and control programs in sheep and dog populations to decrease the odds of human infections. Public health education campaigns are required to be implemented at the community level to reduce the risk of acquiring CE in humans in the Kurdistan region, Iraq.

Echinococcus spp. and genotypes infecting humans in Tibet Autonomous Region of China: a molecular investigation with near-complete/complete mitochondrial sequences

Background

Molecular markers are essential to identify Echinococcus species and genotypes in areas with multiple Echinococcus species to understand their epidemiology and pathology. Tibet Autonomous Region (TAR) is one of the areas worst hit by echinococcosis. However, molecular epidemiology is still missing among echinococcosis patients in TAR. This research explored the Echinococcus species and genotypes infecting humans in TAR and the population diversity and the possible origin of G1 in TAR.

Methods

Cyst samples were collected in one echinococcosis-designated hospital in TAR. Echinococcus species and genotypes were identified through a maximum-likelihood approach with near-complete/complete mtDNA using IQ-TREE. Phylogenetic networks were built with PopART, and the phylogeographical diffusion pattern was identified using a Bayesian discrete phylogeographic method.

Results

Using phylogenetic trees made with near-complete/complete mtDNA obtained from 92 cysts from TAR patients, the Echinococcus species and genotypes infecting humans in TAR were identified as Echinococcus granulosus (s.s.) G1 (81, 88.04%), accounting for the majority, followed by G6 of the E. canadensis cluster (6, 6.52%), E. granulosus (s.s.) G3 (3, 3.26%), and E. multilocularis (2, 2.17%). An expansion trend and a possible recent bottleneck event were confirmed among the G1 samples in TAR. Adding the other near-complete mtDNA of G1 samples globally from the literature, we identified the possible phylogeographic origin of the G1 samples in TAR as Turkey.

Conclusions

Using near-complete/complete mtDNA sequences of Echinococcus spp. obtained from echinococcosis patients, a variety of Echinococcus species and genotypes infecting humans throughout TAR were identified. As far as we know, this is the first comprehensive molecular investigation of Echinococcus species and genotypes infecting humans throughout TAR. We identified, for the first time to our knowledge, the possible origin of the G1 in TAR. We also enriched the long mtDNA database of Echinococcus spp. and added two complete E. multilocularis mtDNA sequences from human patients. These findings will improve our knowledge of echinococcosis, help to refine the targeted echinococcosis control measures, and serve as a valuable baseline for monitoring the Echinococcus species and genotypes mutations and trends of the Echinococcus spp. population in TAR.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05199-6.

Genetic structure and phylogeography of Echinococcus granulosus sensu stricto genotypes G1 and G3 in Pakistan and other regions of the world based on nad5 gene

Pakistan is a neglected endemic focus for Echinococcus granulosus sensu lato, a zoonotic parasite species complex with the ability to infect wide spectrum of hosts. Wide gaps exist in literature for etiological agents of cystic echinococcosis (CE) in Pakistan due to a very low number of studies on identifying the exact genotypes involved in epidemiological manifestation of this disease. Focusing on transmission patterns and epidemiological dynamics, this study aimed at investigating infective genotypes among the cattle population of south Punjab, Pakistan, employing a mitochondrial marker nad5 (680 bp). Nucleotide sequences retrieved from 28 hydatid cyst isolates displayed considerable intraspecific variation revealing the existence of G3 and G1 strains of Echinococcus granulosus sensu stricto. The G3 genotype emerged as the predominant cause (78.57%) of hydatidosis in cattle. Apart from this, to understand phylogeographical relations, homologous nucleotide sequences of the partial nad5 gene from six major regions of the world were employed in the population genetics analysis to have an insight into genetic variability and demographics of G3 genotype in particular. Diversification of G3 and its haplotypes in Pakistan (n = 11) and other regions of the world (India, Iran, Turkey, Italy and France) was demonstrated. It was further demonstrated that the South Asian population (Pakistan and India) was highly differentiated from the other regions. It could, therefore, be speculated that G3 is diverging and expanding its population with South Asia as the main focal point.

Human Cystic Echinococcosis in Lebanon: A Retrospective Study and Molecular Epidemiology

Purpose

Human cystic echinococcosis (CE) is a zoonotic parasitic disease that constitutes a public health challenge and a socio-economic burden in endemic areas worldwide. No specific surveillance system of CE infections in humans exists in Lebanon. The incidence and trends over time have not been documented. The current study aimed to assess the demographic and epidemiologic features of human CE surgical cases over a 14-year period in the five main regions of Lebanon.

Methods

From 2005 to 2018, a total of 894 surgically confirmed cases of hydatidosis were recorded from five anatomy and pathology laboratories.

Results

The mean annual surgical incidence was 1.23/100,000 inhabitants. Over the span of these years, the incidence increased from 0.53 to 1.94 cases/100,000 inhabitants in 2005 and 2018, respectively. CE is present in Lebanon with an uneven distribution from one region to the other with higher prevalence in Bekaa (29.0%), a rural area where sheep raising is widespread. Human CE cases were more common in females (60.1%) than in males (39.9%) and a high burden of infection was reported for the age group of 30–39 years. Besides, 66.7% of the cases expressed only liver complications whereas, 20.5% showed predilection towards lungs. The 7.8% of cases presented cysts in other organs, and 1.3% showed multiple localizations. Additionally, predominant involvement of Echinococcus granulosus sensu stricto was recorded in human infections. Comparison of Echinococcus granulosus s.s. populations from different Mediterranean countries also revealed high gene flow among this region and sharing of alleles.

Conclusion

The current study is a step forward to fill the gap of knowledge for the hydatidosis in Lebanon where the lack of epidemiological data and control measures have resulted in higher incidence of human CE.

Graphic Abstract

Sequence analysis, intra-genotyping variation, and phylogenetic study of nad1 gene in Echinococcus granulosus sensu lato genotypes from intermediate hosts in southwestern Iran

Cystic echinococcosis (CE) is caused by the larval stage of Echinococcus granulosus sensu lato (s. l.). The disease is cosmopolitan, and Iran is a highly endemic area for CE. This parasite exhibits high genetic diversity, which can be related to its life cycle, transmission, and pathogenesis. This study was aimed at determining the phylogenetic relationship and intra-genotyping variation of E. granulosus s.l. in a vast area in the southwest of Iran (SWI). Eighty hydatid cyst isolates of intermediate hosts (i.e., cattle, sheep, goat, buffalo, camel, and human) were collected. The sequence analysis of the nad1 gene exhibited the three genotypes of G1 (n = 70, 87.5%), G3 (n = 8, 10%), and G6/G7 (n = 2, 2.5%). Also, 16, 2, and 1 unique haplotypes were identified for the G1, G3, and G6/G7 genotypes, respectively. According to the phylogenetic tree topology, the nad1 gene similarities were found for some G1 isolates in some vast areas, and the G1 genotype showed a heterogeneous population worldwide. The only SWI G6/G7 haplotype was at a distant position in E. canadensis clade, indicating the notable difference of this haplotype from other isolates from Iran and other countries. The presence of the G6/G7 genotype in the SWI may be due to the transmission of the genotype from other regions or the role of camel/wild boar or other possible hosts in the expansion of this genotype in SWI. The results of the present study can be used in CE control programs, molecular epidemiology, and phylogenetic studies in Iran and other countries for future goals.

Molecular Characterization and Haplotype Analyses of Lung Hydatid Cyst Isolates of Cattle and First Report of Echinococcus canadensis (G6/G7) in Cattle Isolates in Turkey

PURPOSE

Cystic echinococcosis (CE) is a zoonotic disease, caused by parasite known as Echinococcus granulosus sensu lato complex, leading to substantial economic losses in rural areas with public health problems. This study was carried out to understand the haplotypic profiles of the partial mitochondrial cytochrome c oxidase (mt-CO1) gene of cattle lung hydatid cyst samples which were obtained from two provinces in Turkey.

METHODS

In this study, forty (n = 40) hydatid cyst samples from the lungs of slaughtered cattle were obtained. The germinal layers were taken separately for each individual cyst then stored in 70% ethanol. From each individual cyst sample, total genomic DNA was extracted. Amplification of the partial mt-CO1 gene (875 bp) was performed using a specific primer set by PCR, and then, the amplicons were sequenced. All sequences were analyzed individually, followed by alignment, and haplotype and phylogenetic analyses were then performed.

RESULTS

By the sequence alignment process, 39 out of the 40 sequences were characterized as E. granulosus sensu stricto. However, one of them was matched with E. canadensis (G6/G7). The haplotype analyses of the E. granulosus s.s. isolates were arranged in a star-like orientation with a main haplotype, which was separated from other haplotypes by 1-10 mutation steps, and 26 haplotypes were identified. In the mt-CO1 sequences, 29 polymorphic sites were determined, and 34.5% (10/29) of them were parsimony informative.

CONCLUSIONS

The findings of this study provide the first report of E. canadensis (G6/G7 genotype) among cattle in Turkey.

Echinococcus granulosus sensu stricto G1 is the predominant genotype in human and livestock isolates from Turkey and Iran, based on mitochondrial nad5 gene differentiation

Background

Different genotypes of Echinococcus granulosus sensu stricto (s.s.) isolated from livestock and humans have been identified based on cox1 and nad1 genomic fragments. The present study was performed to differentiate the G1/G3 genotypes of Echinococcus granulosus (s.s.) isolated from humans and livestock (sheep and cattle) from Azerbaijan in northwestern Iran, Fars Province in southern Iran, and Van province in Eastern Turkey, using the nad5 gene fragment as a suitable marker to distinguish these two genotypes.

Methods

A total of 60 pathologically confirmed human hydatid cysts and 90 hydatid cyst samples from livestock were collected from Turkey and Iran. PCR was performed on all of the samples, targeting the nad5 gene. Based on PCR product quality, host type, and the geographical area where the samples were obtained, 36 of the samples were sequenced and were used in the phylogenetic analysis.

Results

Out of 36 evaluated samples, 26 (72.2%) samples belonged to G1, and 10 (27.8%) samples belonged to the G3 genotype. Out of 21 samples from Turkey, 16 (76.2%) were G1 and 5 (23.8%) were G3, while out of 15 samples from Iran, 10 (66.7%) were G1 and 5 (33.3%) were the G3 genotype. None of the samples isolated from humans in Iran or from sheep in Turkey were G3. Overall, between the two countries, 18.18% of E. granulosus isolates in cattle, 41.66% of isolates in sheep, and 23.07% of human samples were identified as G3, and the others as the G1 genotype. The G3 genotype was not detected in human samples from Iran or sheep samples from Turkey.

Conclusion

The findings of the study revealed that the G1 genotype of E. granulosus s.s. is the predominant genotype in humans and livestock, both in Turkey and Iran. The ratio of the E. granulosus s.s. G1 to G3 genotype was 3.2 in Turkey and 2 in Iran. The study also further confirmed that the nad5 gene properly differentiated the G1/G3 isolates of E. granulosus from both humans and livestock.

Graphical Abstract

Genetic diversity and transmission patterns of Echinococcus granulosus sensu stricto among domestic ungulates of Sardinia, Italy

Cystic echinococcosis (CE), a parasitic zoonosis of public health and economic concern, is highly endemic in Sardinia, Italy. The study involved examining the intraspecific variability and demographic structure of Echinococcus granulosussensu stricto (s.s.) in common hosts of this parasite. Molecular surveillance included the fragment amplification of a partial mitochondrial gene, cox1 (750 bp), for a total of 69 isolates derived from sheep (n = 52), cattle (n = 11), pigs (n = 4), and goats (n = 2). It was ascertained that E. granulosus s.s. was the primary agent of infection among these ungulates and G1 genotype was highly prevalent (79.71%). Considerable intraspecific variation was found, revealing the existence of 22 haplotypes with relatively high haplotype (0.8555 ± 0.033) and low nucleotide diversities (0.00281 ± 0.00030). Population demographics indicated an expanding parasitic population signifying negative deviation from neutrality indices. Little genetic differentiation was found between the subpopulations of E. granulosus s.s. in the island. Moreover, the geographic dispersal of genotypes G1 and G3 also indicated similarity between Sardinian and mainland Echinococcus granulosus s.s. populations reaffirming the sympatric occurrence and efficient transmission of G1 and G3 genotypes. Molecular survey of CE has the potential to yield baseline information on the infective genotypes among the intermediate hosts and helps in devising suitable control strategies for curtailing the disease.

Cystic echinococcosis in sheep and goats of Lebanon

Cystic echinococcosis (CE), a zoonotic disease caused by the species complex of Echinococcus granulosus sensu lato (s.l.), is endemic in Middle East and the Mediterranean basin, where pastoral activity is widespread. Despite the chronic endemicity of the disease in Lebanon and neighbouring countries, recent data are scant. The objectives of this survey were to evaluate the current epidemiology of CE in Lebanon, investigate the prevalence and determine the infecting genotypes in locally raised sheep and goats. A multidimensional approach combining post-mortem inspection of slaughtered animals and molecular diagnosis of the parasite was conducted to this end. From 2018 to 2020, 62.9% of the sheep and 20.9% of the goats were found positive for CE. The presence of hydatids varied between organs, showing higher prevalence in the liver of sheep vs the lungs of goats, however, a higher fertility rate of hydatid cyst was observed in lungs for both animals. Molecular diagnosis based on partial mitochondrial cox1 gene (795 bp) showed that the majority of isolates were identified as E. granulosus sensu stricto (98.7%) and only one isolate from goat was identified as Echinococcus canadensis (genotype G7; 1.3%). Echinococcus granulosus s.s. population among the sheep and goats was represented by 22 haplotypes having very little genetic differentiation and relatively moderate haplotype diversity. Population demographics explored through neutrality indices suggested expanding population within the intermediate hosts. These results document the high prevalence of CE in the livestock of Lebanon and reveal for the first time the presence of three different genotypes G1, G3 and G7.

A new molecular nomenclature for Taenia hydatigena: mitochondrial DNA sequences reveal sufficient diversity suggesting the assignment of major haplotype divisions

Cysticercosis caused by the metacestode larval stage of Taenia hydatigena formerly referred to as Cysticercus tenuicollis is a disease of veterinary importance that constitutes a significant threat to livestock production worldwide, especially in endemic regions due to condemnation of visceral organs and mortality rate of infected young animals. While the genetic diversity among parasites is found to be potentially useful in many areas of research including molecular diagnostics, epidemiology and control, that of T. hydatigena across the globe remains poorly understood. In this study, analysis of the mitochondrial DNA (mtDNA) of adult worms and larval stages of T. hydatigena isolated from dogs, sheep and a wild boar in China showed that the population structure consists of two major haplogroups with very high nucleotide substitutions involving synonymous and non-synonymous changes. Compared with other cestodes such as Echinococcus spp., the genetic variation observed between the haplogroups is sufficient for the assignment of major haplotype or genotype division as both groups showed a total of 166 point-mutation differences between the 12 mitochondrial protein-coding gene sequences. Preliminary analysis of a nuclear protein-coding gene (pepck) did not reveal any peculiar changes between both groups which suggests that these variants may only differ in their mitochondrial makeup.

Identification of Echinococcus granulosus Genotypes G1 and G3 by SNPs Genotyping Assays

Echinococcus granulosus sensu lato (s.l.) is the causative agent of cystic echinococcosis in animals and humans. Different E. granulosuss.l. genotypes exhibit great diversity in their life cycle, host selectivity and pathogenicity. For this reason, the study of genetic variation within Echinococcus species is of importance for their epidemiological implication. We employed two SNP genotyping technologies to distinguish G1 and G3 E. granulosus sensu stricto (s.s.). genotypes. The genotypes of DNA samples (n = 28) extracted from hydatid cysts of different animal species were identified by amplification and sequencing of a fragment of the mitochondrial nad5 gene. Two SYBR green and three TaqMan real time PCR assays were developed for targeting of three nad5 informative positions (SNP758, 1123, and 1380) known to be able to discriminate G1 from G3. Genotyping by SYBR Green PCR based on cycle threshold (Ct) with melting temperature (Tm) analysis and performed on SNP1123 and SNP1380 failed to identify one DNA sample. TaqMan assays for SNP758, 1123 and 1380 effectively confirmed genotype identification obtained by Sanger sequencing. Our results demonstrated that the combination of the three Taqman assays developed in this study represents a valuable and cost effective tool alternative to DNA sequencing for E. granulosus s.s. genotyping.

Tacrolimus, a rapamycin target protein inhibitor, exerts anti-cystic echinococcosis effects both in vitro and in vivo

In view of a growing need for new treatment options for human cystic echinococcosis (CE), we aimed to investigate the efficacy of mTOR pathway inhibitors against CE in vitro and in vivo. Among the seven mTOR inhibitors evaluated, tacrolimus (TAC) showed significant dose- and time-dependent killing of cultured protoscoleces and cysts in vitro. Notably, the oral administration of TAC (4 mg/kg/day) to CE mice model highly effectively reduced both the weight and number of parasitic cysts. Transmission electron microscopy revealed that TAC destroys the ultrastructure of cysts, both in vitro and in vivo. Furthermore, TAC had no significant effect on blood glucose, body weight, liver, or kidney functions in mice. We further observed that the ATP levels and glucose content of cysts reduced upon TAC treatment, indicating that inhibiting mTORC1 activity possibly affects glucose metabolism in the cysts of mice. Based on our experimental data, TAC emerged as a promising anti-cyst drug that efficiently inhibits the growth of cysts.

A validated method to identify Echinococcus granulosus sensu lato at species level

The zoonotic tapeworm Echinococcus granulosus sensu lato (s.l.) represents a species complex encompassing multiple causative agents of cystic echinococcosis, a neglected tropical disease affecting more than one million people in the world. At least eight genotypes, grouped in five species, are currently recognized within this species complex, and they differ in terms of relative public health impact. Here we present a molecular method that first identifies the common E. granulosus sensu stricto (s.s.) (genotypes G1 and G3) based on a PCR-RFLP assay, and can further identify the remaining species based on a multiplex PCR assay. We demonstrate the applicability of the method to DNA extracted from parasitic cyst material of human and animal origin, preserved in ethanol or frozen. The method has been developed and validated at the European Union Reference Laboratory for Parasites (EURLP), according to the ISO/IE 17025.

Molecular Characterization of Echinococcus granulosus sensu lato from Humans in Slovenia

The larval form of tapeworms of the Echinococcus granulosus sensu lato species cluster cause an important zoonotic infection, cystic echinococcosis (CE). Molecular characterization of the cluster’s isolates from different hosts greatly contributes to a better understanding of its transmission dynamics. To date, no genetic information is available on CE in Slovenia. In this work, we characterized isolates from human CE cases. Parasite samples from 18 patients were collected, together with the patients’ demographic and clinical data. Genomic DNA was analyzed by conventional PCR and sequencing at four mitochondrial loci (cytochrome c oxidase subunit 1, cox1; NADH dehydrogenase subunit 1, nad1; NADH dehydrogenase subunit 5, nad5; and small ribosomal RNA, rrnS). Thirteen isolates were successfully amplified and sequenced. Seven (58.8%) patients were infected with E. granulosus sensu stricto (s.s.) G1, five (38.5%) with E. canadensis G7 and one (7.7%) with E. granulosus s.s. G3. Echinococcus canadensis G7, the pig genotype, was identified exclusively in autochthonous Slovenes, while the patients originating from the Western Balkans were all infected with E. granulosus s.s. Our findings suggest that pigs are important intermediate hosts for human CE in Slovenia.

The Molecular Epidemiology of Echinococcus Infections

Molecular epidemiology (ME) is the application of molecular tools to determine the causation of disease. With infectious diseases, such as echinococcosis, this applies to identifying and characterising the aetiological agents and elucidating host range. Such an approach has been very successful with the causative agents of echinococcosis, species of Echinococcus, initially by providing a workable and practical taxonomy and subsequently determining transmission patterns in endemic areas. This review summarises the taxonomy and nomenclature of species of Echinococcus and provides an update on ME investigations of the ecology of Echinococcus transmission, particularly in areas where more than one species of Echinococcus is maintained in cycles of transmission that may interact.

International consensus on terminology to be used in the field of echinococcoses

Echinococcoses require the involvement of specialists from nearly all disciplines; standardization of the terminology used in the field is thus crucial. To harmonize echinococcosis terminology on sound scientific and linguistic grounds, the World Association of Echinococcosis launched a Formal Consensus process. Under the coordination of a Steering and Writing Group (SWG), a Consultation and Rating Group (CRG) had the main missions of (1) providing input on the list of terms drafted by the SWG, taking into account the available literature and the participants’ experience; and (2) providing independent rating on all debated terms submitted to vote. The mission of the Reading and Review Group (RRG) was to give an opinion about the recommendation paper in terms of readability, acceptability and applicability. The main achievements of this process were: (1) an update of the current nomenclature of Echinococcus spp.; (2) an agreement on three names of diseases due to Echinococcus spp.: Cystic Echinococcosis (CE), Alveolar Echinococcosis (AE) and Neotropical Echinococcosis (NE), and the exclusion of all other names; (3) an agreement on the restricted use of the adjective “hydatid” to refer to the cyst and fluid due to E. granulosus sensu lato; and (4) an agreement on a standardized description of the surgical operations for CE, according to the “Approach, cyst Opening, Resection, and Completeness” (AORC) framework. In addition, 95 “approved” and 60 “rejected” terms were listed. The recommendations provided in this paper will be applicable to scientific publications in English and communication with professionals. They will be used for translation into other languages spoken in endemic countries.

Complete mitochondrial genome analysis confirms the presence of Echinococcus granulosus sensu lato genotype G6 in Nigeria

Cystic echinococcosis (CE) is common in Africa especially in northern and eastern countries where it is highly prevalent and mainly caused by Echinococcus granulosus sensu stricto and Echinococcus granulosus sensu lato (G6/7). In a recent epidemiological survey in Nigeria, the G6/7 genotype was reportedly responsible for the majority of CE infection. In this study, considering the taxonomic challenges of the G6/7 genotype and the limitation of the cox1/nad1 genes in resolving the differences, we sequenced the complete mitochondrial (mt) genome of seven larval isolates of E. granulosus s.l. G6/7 haplotypes recently reported in Nigeria to correctly assign them to either (G6/7) genotype and to understand the mt genome variation with isolates from other geographical regions. On analysis, a total of 13,731 bp in a covalently closed circular molecule were realized. The total mt length was ≥10 bp than previously reported G6 and G7 mt genome sequences. Also, the median-joining network and phylogeny based on the 12 protein-coding sequences correctly identified them as G6 genotype. Since longer mt genome sequences have shown some advantage over individual genes in resolving taxonomic challenges, we confirm that the genotype responsible for the majority of CE infection in livestock in Nigeria is the G6 genotype and the availability of the complete mt genome from different Nigerian intermediate hosts will prove useful in future genetic population studies across the country and the West African sub-region.

Molecular survey on cattle and sheep hydatidosis and first detection of Echinococcus canadensis (G6/G7) in sheep in Turkey

Larval stage of genus Echinococcus is the causing agent for the zoonotic infection which is life threatening known as Echinococcosis. The purpose of this study was the identification, molecular analysis and characterization of Echinococcus spp. in sheep and cattle. The sampling was done from slaughterhouse of Elazig, Turkey. A total of 85 isolates (sheep, n = 19 and cattle, n = 66) have been collected after slaughtering. Following the gDNA isolation and PCR products of mt-CO1 gene (446 bp) of all the samples were sequenced. Out of 85 isolates, 84 were recognized as Echinococcus granulosus sensu stricto and one sheep isolate was found as Echinococcus canadensis (G6/G7 ) which is identified for the first time in Turkey. However, single nucleotide polymorphism has been observed not only in samples of different animals but also in samples collected from the same cattle. Six liver and three lung hydatid cysts have been detected in cattle. Although no nucleotide differences have been observed in the liver samples, there was single nucleotide polymorphism (C→T) in 40th nucleotide of two lung cysts. As a result of haplotype analysis, 16 haplotypes of E. granulosus s.s. were detected in 66 cattle isolates whereas 7 haplotypes of E. granulosus s.s. were identified in 19 sheep samples.

Comparison of molecular and morphological characterization and haplotype analysis of cattle and sheep isolates of cystic echinococcosis

Cystic echinococcosis is a zoonotic disease and the second most common foodborne parasitic infection worldwide. The aim of the present study was to investigate genetic variations in G1 and G3 genotypes of Echinococcus granulosus sensu stricto and determine the morphological differences between two genotypes. In total, 119 cystic samples were collected from 48 cattle and 71 sheep in slaughterhouses in four cities in three geographical regions of Turkey regions (Ankara, Central Anatolio region; Ordu, Black Sea region; and Adana, Mersin, Mediterranean region). For molecular characterization of the G1 and G3 genotypes, two gene regions (the complete mt-cox1 gene sequence and partial mt-nad5 gene sequence) were amplified. Haplotype analysis was conducted to determine the nucleotide differences between the complete sequences of the mt-cox1 gene for 47 samples. In addition, morphological parameters in protoscoleces of fertile cysts were measured to determine the relationship between the genotypes and morphometry. According to the obtained genotype and morphometry results, there were no statistically significant differences between the genotypes in terms of the number of hooks, total lengths of large and small hooks, blade lengths of large and small hooks, and widths of small hooks, although there was a statistically significant difference in large hook width (p > 0.05).

Gene expression in human liver fibrosis associated with Echinococcus granulosus sensu lato

Liver fibrosis is a dynamic process that occurs in response to chronic liver disease resulting from factors such as chronic infections, autoimmune reactions, allergic responses, toxins, radiation, and infectious agents. Among the infectious agents, multicellular parasites cause chronic inflammation and fibrosis. Twenty-five patients with different stages of cystic echinococcosis (CE) were enrolled in the study. The expression of ACTA2, COL3A1, IFN-γ, MMP2, MMP9, TGF-β1, and TNF-α genes was determined by qRT-PCR in healthy and fibrotic liver tissue of the CE patients. TGF-β1 expression was evaluated by immunohistochemistry, and histology was conducted to assess the development of liver fibrosis. Expression of MMP9, ACTA2, COL3A1, and MMP2 was found significantly higher in the fibrotic tissue compared to healthy tissue. We observed a significant correlation between TGF-β1 and TNF-α gene expressions and liver fibrosis. The mRNA level of IFN-γ was lower in the fibrotic than in the healthy hepatic tissue. Immunohistochemistry analysis revealed TGF-β1 upregulation in the fibrotic tissue. Histology showed inflammation and fibrosis to be significantly higher in the fibrotic tissue. The findings of this study suggest that Echinococcus granulosussensu lato can promotes fibrosis through the overexpression of TGF-β1, MMP9, ACTA2, COL3A1, and MMP2. The downregulation of IFN-γ mRNA in fibrotic samples is probably due to the increased production of TGF-β1 and the suppression of potential anti-fibrotic role of IFN-γ during advanced liver injury caused by E. granulosussensu lato.

Genetic Diversity of Echinococcus granulosus Isolated from Humans: A Comparative Study in Two Cystic Echinococcosis Endemic Areas, Turkey and Iran

Cystic echinococcosis (CE) is one of the most important zoonotic parasitic diseases caused by the larval stage of Echinococcus granulosus. Based on molecular studies and DNA sequencing, E. granulosus has been classified into 10 different genotypes (G1 to G10). Two neighboring countries, Turkey and Iran, are considered the two main foci of CE in the Middle East. The current study is aimed at examining the genotype diversity of E. granulosus isolated from human clinical samples in Turkey and Iran. Surgically removed human hydatid cysts were collected from East Azerbaijan and Fars provinces in Iran and Van province in Turkey. After extracting DNA, performing PCR, targeting the cox1 gene, the PCR products were purified from the gel and were sequenced from both directions. The sequences were aligned and compared, using BioEdit and also the BLAST program of GenBank. The maximum likelihood tree was constructed based on the Tamura-Nei model, using the MEGAX software. Phylogenetic analysis showed that the human isolated samples were classified into two major clades: G1 (from Iran and Turkey) and G3 (5 samples from northwestern Iran and one sample from Turkey). The mean and degree of genetic divergence (K2P) between the two major clades, G1 and G3, were 0.2% and 0.7 ± 0.4%, respectively. The findings of the current study revealed that the sheep strain (G1) and the less important strain G3 have major roles in the transmission cycle of CE in two neighboring countries, Iran and Turkey. Therefore, it is necessary to interpose the life cycle of this parasite and reduce the disease burden in livestock and humans by adopting common regional preventive and control policies.

Genetic diversity of Echinococcus granulosus sensu stricto in Sardinia (Italy)

Cystic echinococcosis (CE) is a severe parasitic zoonosis caused by the metacestode of the tapeworm Echinococcus granulosus sensu lato (s.l.). The disease has a global distribution representing a significant public health concern. Based on mitochondrial DNA analysis E. granulosus s.l. has been subdivided into five species: E. granulosus sensu stricto (s.s.) (G1, G3 genotype), E. equinus (G4 genotype), E. ortleppi (G5 genotype), E. canadensis (G6-G8, G10 genotype) and E. felidis. E. granulosus s.s., and in particular G1, is the most widespread genotype and the major responsible of human CE cases worldwide. In Italy G1 genotype is higly represented with larger percentages in some hyperendemic areas such as Sardinia. Molecular studies represent a valuable tool to improve our understanding of the E. granulosus epidemiology and CE control strategies. In the present study we investigated genetic variability of E. granulosus s.s. in Sardinia. To this purpose 83 hydatid cysts were collected from different animal species including humans and the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene was partially sequenced (720 bp). Nucleotide sequences from Mediterranean basin were also analyzed for comparison. The phylogenetic network revealed 30 haplotypes grouped around a predominant isolate that had been already reported from other world regions. Haplotype diversity (0.8495 ± 0.0336) and nucleotide diversity (0.003305 ± 0.002014) were similar in Sardinia respect to other Mediterranean countries. Neutrality indices obtained by Tajima's D and Fu's Fs test were significantly negative (p ≤ .01) suggesting expansion of Sardinian population. Low Fixation indices (Fst), ranging from negative values (Algeria, Greece, Spain, other part of Italy) to 0.089 (Albania, France), indicated absence of genetic differentiation, and gene flow between Sardinia and other Mediterranean countries.

Genetic variation of Echinococcus spp. in yaks and sheep in the Tibet Autonomous Region of China based on mitochondrial DNA

Background

Cystic echinococcosis (CE) in humans and livestock is caused by Echinococcus granulosus (sensu lato). In China where CE is endemic, a number of studies have shown that Echinococcus granulosus (sensu stricto) is majorly responsible for CE. However, E. canadensis (G6) which is the second leading cause of CE is now being detected in most parts of the country. In this study, the species diversity and genetic variation of Echinococcus granulosus (s.l.) in four counties in Tibet Autonomous Region of China were investigated.

Methods

Infection with Echinococcus granulosus (s.s.) in yaks and sheep was identified using NADH dehydrogenase subunit 1 and 5 (nad1 and nad5) mitochondrial genes while the genotype G6 of E. canadensis initially diagnosed with NADH dehydrogenase subunit 1 (nad1) was further confirmed by analysis of the complete mitochondrial genome and a phylogenetic network constructed based on the nad2 and nad5 genes.

Results

Out of 85 hydatid cyst samples collected from slaughtered sheep (n = 54) and yaks (n = 31), 83 were identified as E. granulosus (s.s.) G1 (n = 77), G3 (n = 6) and 2 were identified as E. canadensis G6. Analysis of the nad1/nad5 genes revealed 16/17 mutations with 9/14 parsimony informative sites resulting in 15/14 haplotypes, respectively. Haplotype diversity (Hd) and nucleotide diversity (π) of E. granulosus (s.s.) population were 0.650 and 0.00127 for nad1 and 0.782 and 0.00306 for nad5, respectively, with an overall negative Tajima’s D and Fu’s Fs. A low F_ST indicated no genetic difference between isolates from sheep and yaks.

Conclusion

Pockets of infection with E. canadensis (G6, G7, G8 and G10) have been previously reported in sheep, goats, yaks and/or humans in different parts of China. While the G6 genotype has been previously reported in sheep in the Tibet Autonomous Region, the detection in a yak in the present study represents the first to the best of our knowledge. Therefore, we recommend future surveys and control efforts to comprehensively investigate other potential intermediate hosts for the prevalence and genetic diversity of the E. canadensis group (G6, G7, G8 and G10) across the country and their inclusion into the existing CE control programme.

Echinococcus multilocularis and Echinococcus granulosus in canines in North-Khorasan Province, northeastern Iran, identified using morphology and genetic characterization of mitochondrial DNA

Background

Canids are definitive hosts of Echinococcus multilocularis and Echinococcus granulosus. This study aimed to survey these two Echinococcus species in canids of North-Khorasan Province, northeastern Iran, using morphological criteria and genetic characterization of mitochondrial DNA.

Methods

The carcasses of 106 canids, namely 61 jackals (Canis aureus), 23 foxes (Vulpes vulpes), 19 dogs (Canis familiaris) and three wolves (Canis lupus) were collected from the study area in 2013–2014 and examined for Echinococcus species. Morphological features were assessed by microscopy of adult worms. For molecular characterization, DNA was extracted, mostly from the adult worms but also from eggs. DNA fragments of the cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 1 (nad1) mitochondrial genes were amplified and sequenced. Sequences were aligned and compared with reference sequences. Intraspecific and interspecific diversity were calculated and phylogenetic analysis was performed.

Results

Overall, 9.4% of the canids (eight jackals and two foxes) were found infected with E. multilocularis by molecular methods, of which seven cases were also confirmed using morphological description of the adult worms. Echinococcus granulosus was found in 6.6% of the canines (four dogs, two jackals and one wolf) as determined by both molecular methods and adult cestode morphology. All E. granulosus isolates were identified as the G1 genotype. Comparative sequence analysis indicated 0–0.7% and 0% intraspecific divergence within E. granulosus isolates and 0% and 0–0.2% within E. multilocularis isolates for cox1 and nad1, respectively.

Conclusions

This study revealed the presence of E. multilocularis and E. granulosus in canids of North-Khorasan Province of Iran. Jackals were found infected with both E. multilocularis and E. granulosus, but infection with the former species was higher.

First report of Echinococcus granulosus sensu stricto (G1) in Nigeria, West Africa

Echinococcus granulosus sensu stricto is regarded to have the highest zoonotic potential of all Echinococcus taxa. Globally, human infection due to this species constitutes over 88.44% of the total cystic echinococcosis (CE) burden. Here, we report a CE infection in a Nigerian camel caused by E. granulosus G1 genotype. To the best of our knowledge, this report is the first encounter of the G1 genotype in the West Africa sub-region where the G6 genotype is reportedly prevalent, suggesting that the epidemiology of this highly zoonotic group could have a wider host range and distribution in the sub-region, and emphasizes the need for further investigation into the genetic diversity of Echinococcus spp. in Nigeria and across the sub-region.

First molecular description, phylogeny and genetic variation of Taenia hydatigena from Nigerian sheep and goats based on three mitochondrial genes

BACKGROUND

Cysticercosis caused by the metacestode larval stage of Taenia hydatigena is a disease of veterinary and economic importance. A considerable level of genetic variation among isolates of different intermediate hosts and locations has been documented. Generally, data on the genetic population structure of T. hydatigena is scanty and lacking in Nigeria. Meanwhile, similar findings in other cestodes like Echinococcus spp. have been found to be of epidemiological importance. Our aim, therefore, was to characterize and compare the genetic diversity of T. hydatigena population in Nigeria based on three mitochondrial DNA markers as well as to assess the phylogenetic relationship with populations from other geographical regions.

METHODS

In the present study, we described the genetic variation and diversity of T. hydatigena isolates from Nigerian sheep and goats using three full-length mitochondrial genes: the cytochrome c oxidase subunit 1 (cox1), NADH dehydrogenase subunit 1 (nad1), and NADH dehydrogenase subunit 5 (nad5).

RESULTS

The median-joining network of concatenated cox1-nad1-nad5 sequences indicated that T. hydatigena metacestodes of sheep origin were genetically distinct from those obtained in goats and this was supported by high F_ST values of nad1, cox1, and concatenated cox1-nad1-nad5 sequences. Genetic variation was also found to be higher in isolates from goats than from sheep.

CONCLUSIONS

To the best of our knowledge, the present study described the genetic variation of T. hydatigena population for the first time in Nigeria using full-length mitochondrial genes and suggests the existence of host-specific variants. The population indices of the different DNA markers suggest that analysis of long mitochondrial DNA fragments may provide more information on the molecular ecology of T. hydatigena. We recommend that future studies employ long mitochondrial DNA sequence in order to provide reliable data that would explain the extent of genetic variation in different hosts/locations and the biological and epidemiological significance.

Detection and genetic characterization of Echinococcus granulosus mitochondrial DNA in serum and formalin-fixed paraffin embedded cyst tissue samples of cystic echinococcosis patients

Cystic echinococcosis (CE) is a worldwide zoonotic disease caused by the larval stage of Echinococcus granulosus. We investigated the presence of E. granulosus-specific DNA in the serum of CE patients by detecting the cytochrome c oxidase I (cox1) and NADH dehydrogenase subunit I (nad1) mitochondrial genes. Serum and formalin-fixed paraffin embedded (FFPE) cyst tissue samples of 80 CE patients were analyzed. The extracted DNA of samples was submitted to PCR amplification of cox1 and nad1 genes, and products were sequenced and genotyped. Nineteen (23.8%; 95% CI 15.8-34.1) serum and 78 (97.5%; 95% CI 91.3-99.3) FFPE cyst tissue samples were successfully amplified with at least one gene. Echinococcus DNA was detected in the sera of 15.0% (95% CI: 8.8-24.4) and 10.0% (95% CI: 5.2-18.5) and in cyst tissue of 91.3% (95% CI: 83.0-95.7) and 83.8% (95% CI: 74.2-90.3) of 80 patients by cox1 and nad1 gene, respectively. Four genotypes of E. granulosus were distinguished in the CE patients, with predominance of genotype G1, followed by G3, G2, and G6. The finding of E. granulosus DNA in 23.8% of serum samples from CE patients confirmed that E. granulosus releases cell-free DNA into the circulatory system, but quantities may be inadequate for the diagnosis of CE. Genotype G1 predominance suggests the sheep-dog cycle as the primary route of human infection.