Genotyping of Echinococcus granulosus from domestic animals and humans from Ardabil Province, northwest Iran

Molecular characterization of cystic echinococcosis cysts isolated from cattle in Shiraz, Iran

Cystic echinococcosis (CE), is one of the common parasitic infections of domestic animals and humans caused by the larval stages of the tapeworm Echinococcus granulosus. This research aimed to identify of CE cysts in cattle isolates from Shiraz slaughterhouse using molecular technique. Thirty CE cysts isolates were collected and total DNA was extracted from protoscolices or the germinal layer of each cyst followed by polymerase chain reaction (PCR) using cytochrome c oxidase I (cox1) and NADH dehydrogenase subunit 1 (NADH-1) mitochondrial genes (~ 450 bp) and sequencing. The sequence results were compared with available reference sequences in GenBank by BLAST system. Phylogenetic analysis was performed using MEGA 5.0 software and the maximum likelihood method. The results showed that all 30 samples examined in this study were identified as E. granulosus sensu stricto (G1-G3 genotypes) with G1 dominant.

Identification and genotyping of Echinococcus granulosus from human clinical samples in Guilan province, north of Iran

Cystic echinococcosis (CE) is a significant health problem in both human and veterinary medicine. It is caused by the tapeworm Echinococcus granulosus (E. granulosus). The objective of this study was to investigate molecular diversity of E. granulosus from the paraffin-embedded human (FFPE) tissue samples using sequencing of mitochondrial genes. Thirty-five FFPE tissue samples were collected from different regions of Guilan province, north of Iran. Demographic data were recorded using a questionnaire. Five sections (1 mm) of the tissue were prepared and deparaffined using xylene and ethanol methods. Molecular analysis was performed using the Nad1 and Cox1 genes using PCR and DNA sequencing. Totally, 25 cases (71.43%) were women and 10 cases (28.57%) were men. The most affected age group was 21-30 yr old. The most of cysts were isolated from the liver (n = 19; 54.29%) and others in the lung (n = 16; 45.71%). The Cox1 and Nad1 genes were successfully amplified in 16 (45.71%) and 12 (34.28%) DNA samples from FFPE tissue. Sequencing analysis revealed that all samples were E. granulosus sensu stricto complex (G1 and G3). In this study, E. granulosus sensu stricto complex G1 and G3 were identified in human hydatid cysts and showed the presence of sheep/dog cycle in human infection. This finding confirmed and completed previous studies on the geospatial distribution of E. granulosus sensu stricto complex G1 and G3 in the southern and coastal areas of the Caspian Sea region.

Echinococcus granulosus sheep strain (G1) as the predominant genotype in definitive host (dogs) isolates in northeastern Iran

Echinococcus granulosus sensu lato (E. granulosus s.l.) is a zoonotic parasite, causing cystic echinococcosis in humans. In the present study, prevalence and genotypes of E. granulosus s.l. was assessed in stools collected from 244 dogs including 138 stray and 106 domestic animals using high resolution melting curve (HRM) method. Initially, to detect taeniid eggs in feces, all samples were examined using the formalin-ether techniques. Genomic DNA was extracted from the positive samples and E. granulosus s.l. was differentiated from other Taeniidae parasites using SSU-rDNA gene and E. granulosus s.l. was analyzed for genotyping using HRM based on the cox1 gene. In total, 12.7% (31/244) of the samples were positive for Taeniidae eggs. In addition, among the positive samples, 77.4% (24/31) were positive for E. granulosus s.l.. In details, 11.3% (12/106) of the domestic dogs and 8.7% (12/138) of the stray dogs were positive for E. granulosus s.l.. The results of HRM analysis showed that all E. granulosus s.l. isolates were G1 strain. Findings of the present study indicated a considerable prevalence of E. granulosus G1 among dogs in the northeast of Iran and imply a serious risk of transmitting to humans and livestock.

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.

Prevalence of Cystic Echinococcosis Genotypes in Iranian Animals: A Systematic Review and Meta-Analysis

Background

Cystic echinococcosis is considered a public health problem that if left untreated can have dangerous consequences for the person. The disease is caused by Echinococcus granulosus sensu lato larvae. The main risk factors for this parasitic infection are habitat, direct contact with dogs, use of raw vegetables, and use of unwashed vegetables. The most important factors affecting the prevalence of HCD are economic, occupational, agricultural, educational, and factors related to public health and cultural habits of the general public in that geographical area.

Objectives

The purpose of this study was to investigate the prevalence of the types of cystic echinococcosis genotypes (E. granulosus sensu stricto (G₁-G₃) and E. Canadensis (G₆ and G₇)) in livestock in Iran.

Method

This systematic review was conducted, using Medline/PubMed, Scopus, Web of Sciences, and Google Scholar databases, to identify studies of cystic echinococcosis in animals published from 2010 to April 14, 2021. Finally, 28 studies were selected for meta-analysis, which was analyzed using Stata software version 14. The cystic echinococcosis prevalence with 95% confidence intervals of animals was synthesized using the random effect model. Heterogeneity was evaluated and in cases where the I² index was higher than 75%, subgroup analysis was performed according to the types of animals.

Result

The highest prevalence of cystic echinococcosis infection was related to G₁ genotype (P = 0.91 (95% CI = 0.84, 0.97)) and the prevalence was related to G₂ genotype (P = 0.07(95% CI = 0.00, 0.18)). The results of the subgroup analysis showed that in the G₁ genotype the highest prevalence was observed in Goats and Buffaloes with P = 1 (95% CI = 0.96, 1) and P = 1 (95% CI = 0.97, 1), in the G₃ and G₆ genotypes the highest prevalence was observed in camels with P = 0.50 (95% CI = 0.31, 0.69), and P = 0.45 (95% CI = 0.22, 0.69), respectively.

Conclusion

The cystic echinococcosis genotypes vary from region to region or from country to country and also from host to host, and according to the results, it should always be stopped in areas where the prevalence of such genomes suitable for livestock as well as human food sources to prevent infection of livestock and thus human exposure to cystic echinococcosis.

Global distribution of Echinococcus granulosus genotypes in domestic and wild canids: a systematic review and meta-analysis

The current systematic review and meta-analysis demonstrate the genotypic distribution of canine echinococcosis worldwide. Studies published from the inception until 21 May 2021 were screened, relevant articles were selected and the random-effect model was used to draw forest plots with 95% confidence intervals (CIs). Totally, 44 articles were included, mostly examined dogs (37 records), followed by wolf (8 records), jackal (7 records), fox (3 records), pump fox (3 records) and coyote (1 record). Echinococcus granulosus sensu stricto (G1–G3) and G6/7 cluster of Echinococcus canadensis were the most common genotypes among canids. Most studies were conducted in Asia and Europe with 17 and 15 datasets, respectively. Exclusively, Iran possessed the highest number of studies (10 records). Meta-analysis showed that the pooled molecular prevalence of echinococcosis was 33.82% (95% CI 24.50–43.83%). Also, the highest and lowest prevalence of canine echinococcosis was calculated for South America (66.03%; 95% CI 25.67–95.85%) and Europe (19.01%; 95% CI 9.95–30.16%). Additionally, there were statistically significant differences between the global prevalence of echinococcosis in canines and publication year, continent, country, sample type, host and molecular test. These findings will elevate our knowledge on the poorly known canine echinococcosis worldwide.

Echinococcus granulosus sensu lato Genotypes in Different Hosts Worldwide: A Systematic Review

INTRODUCTION

The aim of this study was to develop a synthesis of the evidence available regarding verified E. granulosus sensu lato (s.l.) genotypes in different species worldwide.

MATERIAL AND METHODS

A systematic review was performed including studies concerning genotypes of E. granulosus s.l. without language or genotyped method restriction, published between 1990 and 2020. A systematic search was carried out in Trip Database, BIREME, SciELO, LILACS, IBECS, PAHO-WHO, EMBASE, PubMed, Scopus, and WoS. Variables of interest were year of publication, country, number of samples, and hosts; genotypes, molecular marker, haplotypes and molecular biology techniques used. Descriptive statistics were applied.

RESULTS

2411 articles were analyzed, however 135 met the selection criteria, representing 8643 liver and lung samples. Of the samples selected 24% were human, the remaining samples pertained to non-human animal hosts; cattle and sheep prevailed with 28.6% and 26.6% of the studied samples, respectively. The reported evidence is mainly from Iran, Turkey, Argentina, China and Chile; with 50, 11, 6, 6 and 5 studies, respectively, published between 1992 and 2020 [most frequently during 2015-2020 (76/135 studies; 56.3%)]. The mitochondrial gene cox1 was generally sequenced and informative (91.8%). Genotypes most frequently identified were E. granulosus sensu stricto (s.s.) (83.2%).

CONCLUSIONS

Based on this overall evidence, it can be concluded that publications related to genotypes of E. granulosus s.l. are heterogeneous. E. granulosus ss accounts for the vast majority of the global burden of E. granulosus s.l. worldwide. Further studies including larger number of cases and adequate internal validity are required to specify the distribution of genotypes in various host species.

TRIAL REGISTRATION

PROSPERO CRD42018099827.

Occurrence and genetic characterization of Echinococcus granulosus sensu lato from domestic animals in Central Iran

Background

The species complex of Echinococcus granulosus sensu lato (s.l.) causes cystic echinococcosis distributed worldwide. There is no genotype information from hydatid cysts in the intermediate hosts in Central Iran. Therefore, in this study, we analyzed the hydatid cysts in livestock slaughtered in an abattoir in this region. Six hundred fifty-seven hydatid cysts were isolated from 97 animals, including sheep, cattle, camels, and goats slaughtered in Yazd abattoir from September 2018 to January 2020. The demographic data was collected as well as cyst location, fertility, and viability. Out of 657 samples, 164 samples were genotyped. Then, phylogenetic analysis was performed using MEGAX. Statistical analyses were done using SPSS version 16.0 by chi-square with a significant difference of less than 0.05.

Results

Out of 164 samples, the G1-G3 complex genotype had the most frequency in samples, with 135 cases recognized. The G6/G7 was observed in 19 isolates and G5 was reported in nine samples. One sample was detected as Taenia hydatigena.

Conclusions

This study showed that G1-G3 and G6/G7 genotypes were presented in all animals, but G5 was reported only in cattle, goats, and camels. It is the first molecular identification of cystic echinococcosis in Central Iran. Hence, reporting G5 in livestock in this area should be considered due to transmission to humans.

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.

Echinococcoses in Iran, Turkey, and Pakistan: Old Diseases in the New Millennium

Echinococcosis is considered a cosmopolitan zoonosis caused by different species of small taeniid tapeworms of the genus Echinococcus and is regarded as a neglected zoonosis. Cystic and alveolar echinococcoses are endemic diseases of Tibetan, Pamir, and Iranian plateaus. All of the countries within the Iranian plateau are affected by echinococcosis. Pakistan, Turkey, and Iran are the three most populous countries of the region, in which echinococcosis is highly endemic. The three neighboring countries share strong cultural and socioeconomic ties. The present study aimed to provide a broad review of the status of cystic and alveolar echinococcosis, summarizing the current knowledge about geographical distribution, molecular epidemiology, and transmission dynamics of Echinococcus granulosus sensu lato and Echinococcus multilocularis in this region. Additionally, we aimed to understand disease burden and risk factors as basic requirements for establishing a surveillance system and planning prevention and control programs. A considerable body of information is available on different aspects of echinococcosis in this region; however, several information and research gaps need to be filled before planning control programs. None of the countries in the region have an elaborate echinococcosis control program. Effective control programs require multi/intersectoral coordination within a One Health approach with a long-term political and administrative commitment and enhanced international collaboration among the three countries.

Genetic Characterization of Echinococcus granulosus Sensu Lato in Livestock and Human Isolates from North of Iran Indicates the Presence of E. ortleppi in Cattle

PURPOSE

Identification of different genotypes of echinococcal cyst in various domestic herbivores and humans within the target area was the principal aim of the present study, performed using sequence data of cox1 and nad1 mitochondrial genes.

METHODS

A total of 57 cystic echinococcosis (CE) cysts were isolated from indigenous livestock including 45 cattle, 9 sheep and 3 goats from several slaughterhouses in Guilan Province. Moreover, 12 formalin-fixed paraffin-embedded (FFPE) CE cyst tissues from humans were also included, obtained from the archives of several hospitals in Rasht, the capital of Guilan. Genetic sequencing was conducted using mitochondrial cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 1 (nad1) genes.

RESULTS

Our results found that E. granulosus sensu stricto (s.s.) and E. ortleppi were present in 92.7% and 7.2% isolates, respectively. E. granulosus s.s. (genotypes G1 and G3) and E. ortleppi were isolated from various livestock whereas all CE cysts isolated from humans were E. granulosus s.s. G1 genotype.

CONCLUSION

We found that E. granulosus s.s. G1 was the predominant genotype within the study region. This is the first study to report E. ortleppi in cattle in Iran.

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.

Molecular characterization of Echinococcus granulosus in livestock of Al-Madinah (Saudi Arabia)

Echinococcus granulosus is the causative agent of cystic echinococcosis, which has serious impacts on human and/or animal health, resulting in significant economic losses. Echinococcus granulosus comprises a number of intra-specific variants or strains at the genetic level. In Saudi Arabia, few studies were performed on genetic variations in Echinococcus species. Therefore, the present study aimed to investigate the phenotypic and genetic characterization of hydatid cysts harboured by sheep and camels in Al-Madinah Al-Munawarah. Samples of hydatid cysts were collected from local sheep (n = 25) and camels (n = 8). The morphological criteria of protoscoleces were investigated. To investigate the molecular characterization, random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR), single-stranded conformation polymorphism (SSCP) were carried out. DNA was extracted from individual fertile cysts and subjected to RAPD-PCR analysis (using five arbitrary primers) and PCR amplification of cytochrome c oxidase I (cox1) and 12S ribosomal ribonucleic acid (12S rRNA) genes. The PCR products were subjected to SSCP analysis for genetic discrimination in E. granulosus isolates. In addition, partially sequencing of the mitochondrial DNA cox1 genes was achieved for assessing the phylogenetic positions of collected isolates using some global published sequence data of cox1 genes. The rostellar hooks of camel and local sheep isolates show remarkable variability in their dimensions. Five distinct SSCP patterns were identified in the 12S rRNA gene, showing intraspecific variations in E. granulosus of camels and local sheep. Sequencing of (cox1) genes of both local sheep and camels exhibit high similarity with those of the same gene (E. granulosus sensu stricto) published in NCBI BLAST.

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.

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.

Isolated Human and Livestock Echinococcus granulosus Genotypes Using Real-Time PCR of cox1 Gene in Northeast Iran

PURPOSE

Cystic echinococcosis (CE), caused by the metacestode of Echinococcus granulosus, is highly endemic over large parts of Iran. The purpose of this study was to investigate the prevalence rate of hydatidosis and mitochondrial cox1 real-time PCR with high-resolution melting curve (HRM) analysis of E. granulosus isolated from human and livestock.

METHODS

In this cross-sectional study, 61 formalin-fixed paraffin-embedded tissue isolates were collected from human CE cases and 83 hydatid cysts from the liver and lung lesions of the livestock in Khorasan Razavi province, Northeast Iran. DNA was extracted from each isolate and amplified by real-time PCR and analyzed using the HRM method.

RESULTS

The HRM analysis using the cox1 gene of 40 E. granulosus human isolates showed that 35 (87.5%), 4 (10%), and 1 (2.5%) of the isolates were categorized as G1, G3, and G6 genotypes, respectively. Out of the total 1342 livestock inspected, 39 (4%) goats and 44(12%) cattle were found harboring hydatid cysts all belonging to E. granulosus sensu stricto.

CONCLUSION

The results confirmed that the high prevalence of E. granulosus sensu stricto in intermediate hosts is remarkable in northeast of Iran coupled with the high prevalence of infection in livestock, which reinforced the need for hydatidosis control programs in this region.

Determination of Echinococcus Granulosus Genotypes in Livestock Slaughtered in Shush County, Southwest Iran Using PCR-RFLP

Echinococosis is a zoonotic disease caused by the larval stages of Echinococcus spp. that occurs in most parts of the world. Herein, we aimed to evaluate the genotypes of isolated hydatid cysts from slaughtered animals in Shush county, southwestern Iran. Totally, 96 hydatid cysts were collected, including 11 buffaloes, 13 cattle, 12 goat and 60 sheep. The PCR was done by a primer pair (BDI and 4s) to amplify ITS1 fragment. Four restriction endonucleases including AluI, HpaII, RsaI, and TaqI were used for RFLP products and enzymatic reactions were electrophoresed. Finally, twenty PCR products were sent for sequencing and phylogenetic tree was drawn with MEGA6. Molecular identification of 96 hydatid cysts demonstrated a distinctive 1000 bp fragment in all samples from four animal hosts. RFLP analysis showed similar digestion patterns in all samples. AluI digestion yielded 800 bp and 200 bp fragments, HpaII digestion made 700 bp and 300 bp fragments and RsaI digestion entailed 655 and 345segments. Moreover, TaqI rendered no digestion pattern on rDNA-ITS1 region. Additionally, E. granulosus sensu stricto (G1-3 complex) was the prevailing genotype in all livestock samples, according to PCR-RFLP and sequencing analyses.

Genotyping and phylogenetic analysis of unusually located hydatid cysts isolated from humans in north-east Iran

Despite several studies conducted to determine the genotypes of cystic echinococcosis (CE) agents in humans and other intermediate hosts, the relationship between parasite genotype and clinical presentation of hydatidosis is yet to be well defined. The aim of this study was to compare the genotypes/haplotypes of CE agents of human extra-hepatopulmonary hydatid cysts and common hydatid cysts of the liver. A comparative analysis was carried out between partial cox1 sequences of ten extra-hepatopulmonary hydatid cysts, two liver cysts and reliable sequences from the GenBank database. All the studied hydatid cysts had the Echinococcus granulosus sensu stricto (G1-G2-G3) genotypes. The liver CE cysts were caused by common G1 genotype, while six of the extra-hepatopulmonary cysts had genotypes different from common G1 cysts. The sequences of these six isolates were identical to the G2 and G3 genotypes of E. granulosus sensu stricto; the kidney and peritoneum cysts and most of the brain cysts were identified as G2 genotype, while G3 genotype was only reported in a cyst belonging to the pelvic region. Given the observed differences between the sequences of hydatid cysts, it seems that the replacement of hydatid cysts in organs other than the liver and lungs can be related to their genotypes and probably intra-genotypic characteristics. It was hypothesized that in each geographic area, less frequent genotypes were likely to be more consistent with placement in the host's unusual organs.

A systematic review and meta-analysis of the genetic characterization of human echinococcosis in Iran, an endemic country

Human echinococcosis is an infectious disease caused by tapeworms belonging to the species Echinococcus. This parasite has a worldwide distribution and is considered a neglected tropical disease by the World Health Organization. Due to the diversity of Echinococcus spp. hosts, as well as variation in geographical, climatic, and socio-ethnic conditions, the question of the strains or genotypes of Echinococcus spp. that are involved in human infections is important. The aim of this study was to provide a summary of the available data on genotypes of Echinococcus obtained from the Iranian population. Four international databases (PubMed, Scopus, Science Direct, and Web of Science) and 4 Persian databases (Magiran, Scientific Information Database, Iran Medex, and IranDoc) were searched for cross-sectional studies that reported the genotypes of Echinococcus spp. in human echinococcosis cases using molecular methods in Iran through July 2018. The Newcastle-Ottawa Scale was used to assess the quality of the selected studies. A total of 559 cases of human cystic echinococcosis were reported in the 21 included articles. The majority of cases belonged to genotype G1 (89.2%; 95% confidence interval [CI], 80.1 to 95.8), genotype G6 (8.2%; 95% CI, 2.8 to 15.9), and genotype G3 (2.3%; 95% CI, 1.1 to 3.9). Since genotype G1 of Echinococcus appears to be the most prevalent genotype affecting humans in Iran, disease control initiatives aimed at sheep intermediate hosts may be the most beneficial. In addition, educational programs and serological screening in individuals may help reduce the national impact of the disease.

Genotyping of Echinococcus granulosus isolates from livestock based on mitochondrial cox1 gene, in the Markazi province, Iran

Hydatidosisis a parasitic disease caused by the larval stage of Echinococcus granulosus with different genotypes, and major complications in vital organs such as liver, lungs and, brain. Also, this parasite can infect animals and cause economic damages. Recently, some investigations indicated that the genetic variation of the parasite affects the antigenic, immunogenic and pathogenic features. Therefore, present study conducted to genotyping of the E. granulosus larva based on mitochondrial cox1 gene in livestock in the endemic areas of Markazi province, Iran. In this study, 49 hydatid cysts samples collected from 36 sheep, 11 goats and 2 cattle from different slaughterhouses of Markazi province in central part of Iran, 2017. The mitochondrial cox1 gene was amplified and genotyping were accomplished using sequence analysis. The sequencing analysis indicated that the main genotype G1 (61%) and G3 (37%) were identified. Also, one of the samples shows similarity with the G2 (2%) genotype. The results showed the statistically significant differences between the genotypes in different livestock (P < 0.05). This study indicated that the main genotypes of E. granulosus in Markazi province are G1 and G3 which are related to dog/sheep strain. Therefore, parasite control in dogs and sheep can reduce the risk of transmission of infection to humans.

An analysis of common foodborne parasitic zoonoses in slaughtered sheep and cattle in Tehran, Iran, during 2015-2018

Background and Aim:

Cystic echinococcosis, Echinococcus granulosus, and liver flukes, such as Fasciola spp. and Dicrocoelium dendriticum, are important parasitic zoonoses, where they able to cause significant veterinary, medical, and economic problems. The present study was carried out to obtain the updated knowledge on the frequency of hydatidosis, fasciolosis, and dicrocoeliosis in the slaughtered sheep and cattle.

Materials and Methods:

Information were collected from meat inspection records using systematically visual inspection, palpation, and incision of the visceral organs in the industrial abattoir in Tehran, the capital of Iran, between February 1, 2015, and January 31, 2018. For an analysis of the data, SPSS version 16 was applied.

Results:

The hydatidosis infection in sheep and cattle was 2.48% and 2.25%, respectively. With respect to liver flukes, 0.62% and 0.25% sheep and cattle were infected by Fasciola spp., respectively; furthermore, 2.86% sheep and 0.79% cattle were positive for D. dendriticum.

Conclusion:

The findings will provide considerable awareness for the future monitoring and control of these potentially important infections.

Gene-based molecular analysis of COX1 in Echinococcus granulosus cysts isolated from naturally infected livestock in Riyadh, Saudi Arabia

The diversity and importance of Echinococcus species in domesticated animals in Saudi Arabia are poorly understood. In this study, 108 singular (hydatid) cysts were collected from goats (n = 25), sheep (n = 56) and camels (n = 27). DNA was extracted from the protoscoleces of individual fertile cysts and used for polymerase chain reaction (PCR) amplification of mitochondrial subunit 1 of the cytochrome c oxidase 1 (cox1) gene. Amplicon sequencing results revealed the presence of Echinococcus granulosus sensustricto (s.s.) (genotypes G1–G3) in 16 of the17 sheep cysts and 2 of the 27 camel cysts.of these samples, 18 (2 camel and 16 sheep) were divided into genotypes G1, G2, and G3.

Genetic diversity and phylogeography of the elusive, but epidemiologically important Echinococcus granulosus sensu stricto genotype G3

Cystic echinococcosis (CE) is a severe parasitic disease caused by the species complex Echinococcus granulosus sensu lato. Human infections are most commonly associated with E. granulosus sensu stricto (s.s.), comprising genotypes G1 and G3. The objective of the current study was to provide first insight into the genetic diversity and phylogeography of genotype G3. Despite the epidemiological importance of the genotype, it has remained poorly explored due to the ambiguity in the definition of the genotype. However, it was recently demonstrated that long sequences of mitochondrial DNA (mtDNA) provide a reliable method to discriminate G1 and G3 from each other. Therefore, we sequenced near-complete mtDNA of 39 G3 samples, covering most of the known distribution range and host spectra of the genotype. The phylogenetic network revealed high genetic variation within E. granulosus s.s. G3 and while G3 is significantly less prevalent worldwide than G1, the genetic diversity of both of the genotypes is equally high. We also present the results of the Bayesian phylogeographic analysis, which yielded several well-supported diffusion routes of genotype G3 originating from Turkey and Iran, suggesting the Middle East as the origin of the genotype.

Echinococcus granulosus genotypes in Iran: a systematic review

Cystic echinococcosis (CE) caused by Echinococcus granulosus sensu lato (s.l.) is a significant zoonosis, especially in developing countries of the Middle East, with many studies focusing on CE genotypes in Iran. We performed a systematic review to determine the exact status of E. granulosus genotypes in the country. We explored English (Pubmed, Scopus, ISI Web of Science and Science Direct) and Persian (Magiran, Iran Medex and Scientific Information Database) databases along with Google Scholar. Our review included 73 studies published prior to the end of 2015. In total, 2952 animal (intermediate and definitive) hosts were examined, and the prevalent genotypes comprised G1 (92.75%) and G6 (4.53%) in sheep, cattle, camels, goats and buffaloes; G3 (2.43%) in five herbivore hosts and dogs; G7 (0.2%) in sheep and goats; and G2 (0.06%) in dogs. G1 was mostly dominant in West Azerbaijan, whereas G3 and G6 were identified most frequently in the provinces of Isfahan and Fars, respectively. Regarding human CE infection, 340 cases were reported from Iran, with the identified genotypes G1 (n = 320), G6 (n = 13) and G3 (n = 7). Most CE-infected humans originated from Isfahan province (168 cases), whereas the lowest number of infected persons was noted in Kerman province (two cases). The information obtained from this systematic review is central to better understanding the biological and epidemiological characteristics of E. granulosus s.l. genotypes in Iran, leading to more comprehensive control strategies.

Genotype characterization of livestock and human cystic echinococcosis in Mazandaran province, Iran

Echinococcus granulosus is a helminth from the family Taeniidae, which causes cystic echinococcosis (CE) in humans and diverse livestock around the world. The identification of existing genotypes in different regions is a major step towards the prevention and establishment of control programmes for the disease. This study aimed to detect CE genotypes using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of the internal transcribed spacer-1 (ITS1) gene and sequencing of the cytochrome c oxidase subunit 1 (Cox1) gene in isolates from the central part of Mazandaran province, northern Iran. Forty isolates were collected from sheep, 17 from cattle and 6 from human formalin-fixed paraffin-embedded tissues (FFPE). The ITS1 and Cox1 genes were successfully amplified by PCR in 41 and 42 samples, respectively. PCR-RFLP and sequencing showed that all isolates had the G1-G3 genotypes in this study. Out of 31 isolates subjected to sequencing for the Cox1 gene, 80.7% had the G1 genotype. G2 (16.1%) and G3 (3.2%) genotypes were observed in five sheep and one cattle samples, respectively. Five human isolates were also sequenced for the ITS1 gene, which showed that all samples belonged to the G1 genotype. Ten haplotypes were determined among the isolates by alignment analysis of the Cox1 gene. In summary, this study demonstrated that G1 was the dominant genotype circulating between humans and livestock in the studied region. Furthermore, high genotypic diversity among the CE isolates was observed.

Genetic characterization of Echinococcus granulosus strains isolated from humans based on nad1 and cox1 gene analysis in Isfahan, central Iran

Cystic echinococcosis (CE) is a medically important parasite-caused human disease. Humans may acquire the infection accidentally by ingestion of E. granulosus eggs. The parasite has a broad range of hosts and genotypes, which may affect its aetiological and biological characteristics. The present study aimed to determine the genetic characteristics of human isolates of E. granulosus in Isfahan, Iran. In this cross-sectional study, 50 surgically removed hydatid cysts were collected from hospitalized patients in Al-Zahra Hospital, Isfahan, Iran, over a period of 2 years (2015-2017). DNA was extracted from cyst material, and polymerase chain reactions (PCR) were performed targeting cox1 and nad1 genes. Amplicons were sequenced directly and the resulting sequences were aligned and analysed. Phylogenetic and genetic diversity analyses were also performed. Among the isolates, 43 (86%), 3 (6%) and 4 (8%) out of 50 were E. granulosus (G1), E. granulosus (G3) and E. intermedius (G6), respectively. In total, nine and eight haplotypes were identified by nad1 and cox1 gene analysis, respectively. The haplotype diversity index was higher by cox1 gene analysis (0.547) in G1 strains compared with nad1 (0.433). The G1 genotype was the most predominant isolate from human cases of CE, and the presence of G6 is indicative of an important role of camels in the development of human CE in Isfahan. This is the first report of the G3 genotype causing human CE in Isfahan. Moreover, cox1 gene analysis enables a higher resolution of the genetic diversity of the E. granulosus population compared with nad1 gene analysis.

Cystic echinococcosis in Poland: genetic variability and the first record of Echinococcus granulosus sensu stricto (G1 genotype) in the country

Cystic echinococcosis is one of the most important zoonotic diseases affecting humans and livestock worldwide, and is endemic in Poland. A set of six isolates on larval stages of Echinococcus granulosus sensu lato tapeworms collected from three humans, two pigs and one sheep from Polish foci of CE was examined by DNA sequencing of two mitochondrial genes (cox1, rrnS). The results demonstrated the presence of E. canadensis and E. granulosus sensu stricto in the investigated hydatid cysts. The former species was found in all five isolates from pigs and humans derived from central Poland. In a sheep hydatid cyst originating from Lesser Poland Voivodeship in southern Poland, E. granulosus s. s. (G1 genotype) was identified. This is the first report of an unambiguously autochthonous infection with E. granulosus s. s. in Poland. The global distribution and host affiliations of the commonly occurring G1 microvariant with nucleotide change 56C/T in cox1, detected here in Polish sheep, are discussed. The finding that sheep harboured E. granulosus s. s. may have important consequences for developing effective hydatid control programmes in Poland due to its longer maturation rate in dogs compared with E. canadensis G7. This may lead to greater expenditures for purchasing anthelmintics to provide an appropriate dosing regime in sheep-raising areas of the country.

Molecular characterization of Echinococcus granulosus isolates from Bulgarian human cystic echinococcosis patients

Although cystic echinococcosis (CE) is highly endemic in Bulgaria, there is still scarce information about species and/or genotypes of the Echinococcus granulosus complex that infect humans. Our study tackled the genetic diversity of E. granulosus complex in a cohort of 30 Bulgarian CE patients. Ten animal E. granulosus isolates from neighboring Greece were additionally included. Specimens were comparatively analyzed for partial sequences of five mitochondrial (mt) (cox I, nad I, rrnS, rrnL, and atp6) and three nuclear (nc) genes (act II, hbx 2, and ef-1α) using a PCR-sequencing approach. All 30 Bulgarian isolates were identified as E. granulosus sensu stricto (s.s.) and were showing identical sequences for each of the three examined partial nc gene markers. Based upon concatenated sequences from partial mtDNA markers, we detected 10 haplotypes: 6 haplotypes (H1-H6) clustering with E. granulosus s.s. (G1) and 4 haplotypes (H9-H13) grouping with E. granulosus s.s. (G3), with H1 and H10 being the most frequent in Bulgarian patients. The haplotypes H1, H4, and H11 were also present in Greek hydatid cyst samples of animal origin. In conclusion, E. granulosus s.s. (G1 and G3 genotypes) is the only causative agent found so far to cause human CE in Bulgaria. However, further studies including larger sample sizes and other additional geographic regions in Bulgaria will have to be performed to confirm our results.

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.

Genetic variability of Echinococcus granulosus complex in various geographical populations of Iran inferred by mitochondrial DNA sequences

To investigate the genetic variability and population structure of Echinococcus granulosus complex, 79 isolates were sequenced from different host species covering human, dog, camel, goat, sheep and cattle as of various geographical sub-populations of Iran (Northwestern, Northern, and Southeastern). In addition, 36 sequences of other geographical populations (Western, Southeastern and Central Iran), were directly retrieved from GenBank database for the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. The confirmed isolates were grouped as G1 genotype (n=92), G6 genotype (n=14), G3 genotype (n=8) and G2 genotype (n=1). 50 unique haplotypes were identified based on the analyzed sequences of cox1. A parsimonious network of the sequence haplotypes displayed star-like features in the overall population containing IR23 (22: 19.1%) as the most common haplotype. According to the analysis of molecular variance (AMOVA) test, the high value of haplotype diversity of E. granulosus complex was shown the total genetic variability within populations while nucleotide diversity was low in all populations. Neutrality indices of the cox1 (Tajima's D and Fu's Fs tests) were shown negative values in Western-Northwestern, Northern and Southeastern populations which indicating significant divergence from neutrality and positive but not significant in Central isolates. A pairwise fixation index (Fst) as a degree of gene flow was generally low value for all populations (0.00647-0.15198). The statistically Fst values indicate that Echinococcus sensu stricto (genotype G1-G3) populations are not genetically well differentiated in various geographical regions of Iran. To appraise the hypothetical evolutionary scenario, further study is needed to analyze concatenated mitogenomes and as well a panel of single locus nuclear markers should be considered in wider areas of Iran and neighboring countries.

Echinococcus granulosus sensu lato GENOTYPES IN DOMESTIC LIVESTOCK AND HUMANS IN GOLESTAN PROVINCE, IRAN

Cystic echinococcosis (CE) is a globally parasitic zoonosis caused by larval stages of Echinococcus granulosus. This study investigated E. granulosus genotypes isolated from livestock and humans in the Golestan province, northern Iran, southeast of the Caspian sea, using partial sequencing data of the cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase 1 (nad1) mitochondrial genes. Seventy E. granulosus isolates were collected from animals in slaughterhouses: 18 isolates from sheep, 40 from cattle, nine from camels, two from buffaloes and one from a goat, along with four human isolates (formalin-fixed, paraffin-embedded tissues) from CE patients of provincial hospitals. All isolates were successfully analysed by PCR amplification and sequencing. The sequence analysis found four E. granulosus genotypes among the 74 CE isolates: G1 (78.3%), G2 (2.7%), G3 (15%) and G6 (4%). The G1-G3 complex genotype was found in all of the sheep, goat, cattle and buffalo isolates. Among the nine camel isolates, the frequency of G1-G3 and G6 genotypes were 66.7% and 33.3%, respectively. All four human CE isolates belonged to E. granulosus sensu stricto. This study reports the first occurrence of the G2 genotype in cattle from Iran and confirms the previously reported G3 genotype in camels in the same country.

A rare case of cerebral hydatidosis caused by a G1 genotype of Echinococcus granulosus in a cow from Iran

Hydatidosis is a medically and veterinary important parasitic disease that is endemic in many parts of the world. Unilocular hydatid cysts may develop in almost any part of the body. Up to 70% of hydatid cysts are located in the liver, followed by 25% in the lungs. Cerebral hydatidosis is an uncommon manifestation of the disease, occurring in less than 1/1000 infected hosts, yet diagnosis does pose a problem. We have reported an exceptionally rare case of cerebral hydatidosis in cattle. This is the first report to describe the characteristic pathological features of the cerebral hydatidosis in cattle caused by the G1 genotype of Echinococcus granulosus. Genotypic analysis was performed on a hydatid cyst from a cow originating from southern Iran, based on the sequence analysis of the cox1 mitochondrial gene.

Genetic characterization of livestock and human hydatid cyst isolates from northwest Iran, using the mitochondrial cox1 gene sequence

Cystic echinococcosis (CE), caused by larval stages of the tapeworm Echinococcus granulosus, is one of the most important zoonoses distributed worldwide. Genotype analysis of the parasite isolates from various hosts is required to better understand the host specificity and transmission routes. The aim of this study was to identify the genotypes of E. granulosus isolated from humans and domestic animals from northwest of Iran (Zanjan Province) using the mitochondrial cox1 gene sequence. A total of 86 hydatid cysts including 49 sheep and 28 cattle isolates from the slaughterhouse and nine human isolates from surgical wards of local hospitals were collected. The isolates were subjected to DNA extraction, PCR amplification, and sequence. Eighty-two (95.35 %) isolates, including 47 sheep, 26 cattle, and all nine human isolates, were determined as G1 genotype, and the remaining four (4.65 %), including two sheep and two cattle isolates, were identified as G3 genotype. From the cox1 sequence data, 13 different haplotypes (10 G1s and three G3s) were detected and named as EGH1-EGH13 (GenBank accession numbers, KP859559-KP859571). EGH1 was the major variant among the haplotypes, and it was identified in 46 (53.49 %) isolates (31 sheep, 14 cattle, and one human). Alignment of the partial cox1 sequences showed 12 point mutations including seven (58.3 %) synonymous and five (41.7 %) non-synonymous substitutions. Based on the results, G1 was the major genotype of E. granulosus in northwest of Iran affecting sheep, cattle, and humans. In addition, a minor group of G3 genotype was found to be circulating in this region.

Genetic characterization of Echinococcus granulosus from a large number of formalin-fixed, paraffin-embedded tissue samples of human isolates in Iran

Cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus, presents an important medical and veterinary problem globally, including that in Iran. Different genotypes of E. granulosus have been reported from human isolates worldwide. This study identifies the genotype of the parasite responsible for human hydatidosis in three provinces of Iran using formalin-fixed paraffin-embedded tissue samples. In this study, 200 formalin-fixed paraffin-embedded tissue samples from human CE cases were collected from Alborz, Tehran, and Kerman provinces. Polymerase chain reaction amplification and sequencing of the partial mitochondrial cytochrome c oxidase subunit 1 gene were performed for genetic characterization of the samples. Phylogenetic analysis of the isolates from this study and reference sequences of different genotypes was done using a maximum likelihood method. In total, 54.4%, 0.8%, 1%, and 40.8% of the samples were identified as the G1, G2, G3, and G6 genotypes, respectively. The findings of the current study confirm the G1 genotype (sheep strain) to be the most prevalent genotype involved in human CE cases in Iran and indicates the high prevalence of the G6 genotype with a high infectivity for humans. Furthermore, this study illustrates the first documented human CE case in Iran infected with the G2 genotype.

Molecular characterization and sequence analysis of Echinococcus granulosus from sheep isolates in East Azerbaijan province, northwest of Iran

Echinococcus granulosus as an etiologic agent of hydatid cyst is one of the most important zoonotic helminthes in the world that causing enormous economic and health losses. The aim of this study was to evaluate genotype of E. granulosus isolated from sheep using mitochondrial cytochrome c oxidase subunit 1 (cox1) gene and sequencing method in East Azerbaijan province, northwest of Iran. Nineteen sheep hydatid cyst samples were collected. Genomic DNA was extracted from protoscoleces using commercial DNA extraction kit. Mitochondrial cox1 region was amplified by polymerase chain reaction (PCR) and all isolates were sequenced. Afterward, sequences were analyzed for determination of genotypes by related software. G1 (94.73 %) and G3 (5.27 %) genotypes were identified from the isolates which out of 19 hydatid cysts, 17 samples were G1B, 1 sample G1D and the other one had G3 genotype. Results of this study indicate that common sheep strain (G1); especially G1B is the dominant subtype of E. granulosus in East Azerbaijan province.

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.