Genotyping Echinococcus granulosus from dogs from Western Iran

Morphometrical and molecular identification of Echinococcus granulosus genotypes in wild canids in north of Iran

BACKGROUND/OBJECTIVE

The cestode Echinococcus granulosus causes cystic echinococcosis, a zoonotic parasitic infection that constitutes a significant public health risk. This parasite has been documented to have potential reservoirs and carriers among wild canids, namely wolves, foxes and jackals. This study aimed to determine the prevalence and molecular characteristics of E. granulosus sensu lato species/genotypes among wild canids in three northern, northeastern and north-western Iran regions.

METHODS

From 2019 to 2022, 93 wild canid carcasses (69 jackals), (22 foxes) and (2 wolves) were collected that were killed in car accidents or illnesses. Analyses of morphology and morphometry were performed to verify the presence of E. granulosus. To determine E. granulosus s.l. species/genotypes, polymerase chain reaction (PCR)-RFLP (ITS1) was performed utilizing the Bsh1236I (BstUI) restriction enzyme. COX1, NADH1 and ITS1 gene sequencing were also performed to confirm the PCR-RFLP results.

RESULTS

During this study, 93 wild canids were examined, and 3.2% (95% CI: 0%-7%) of the 93 were infected with Echinococcus. The north-western region of Iran showed two out of 30 jackals (6.6%) infected with adult Echinococcus compared to one out of 35 jackals (2.8%) in the northern region. DNA from Echinococcus was detected in these individuals by PCR. Based on PCR-RFLP analysis of the ITS1 gene and sequencing of COX1, NADH1 and ITS1 gene, E. granulosus sensu stricto genotype was confirmed in the jackals that had been infected.

CONCLUSION

Evidence shows that E. granulosus occurs in jackals in Iran, with the E. granulosus s.s. genotype being the most common. This parasite has been identified as a zoonotic parasite with a genotype that can be transmitted to livestock and humans. Establishing effective control measures to prevent the spread of echinococcosis and ensure public health is crucial.

Global distribution and definitive host range of Echinococcus species and genotypes: A systematic review

Echinococcus species (spp.) are regarded as neglected cestodes causing several potential zoonoses of global public health. This systematic review critically appraises the worldwide distribution of Echinococcus spp. and genotypes (Echinococcus spp.: recognized species in the genus; genotypes: variants identified within E. granulosus sensu lato.) in definitive hosts. We analyzed 82 studies from major databases, comprising 24 individual host species, including canids, felids, and a hyenid species. Canids, particularly dogs, were the most studied group among the host species, with E. granulosus sensu stricto (G1-G3) being the most frequently reported. E. granulosus s.s. was distributed across five major continents, while other Echinococcus spp. and genotypes exhibited an uneven continental distribution. The highest overlap of species existed among Asia, Europe, and Africa. Among the reported host species, 4.2 % were endangered (e.g. Lycaon pictus), 12.5 % species were vulnerable (e.g. Panthera leo, Panthera pardus, and Acinonyx jubatus), and 4.2 % were near threatened (e.g. Speothos venaticus). Overall, our review highlights the significance of canids, particularly dogs, as the core focus of scientific investigations, with E. granulosus s.s. being the most widely distributed species across five major continents, emphasizing the urgent need for continued research and public health efforts.

Gastrointestinal parasites of dogs and foxes in the Zanjan province of Iran: With an emphasis on Echinococcus species

Canids harbor many zoonotic parasites and play an important role in the spread of parasites in the human environment. Estimation of parasitic infection among canids as definitive hosts may help competent authorities design efficient control programs. This study was conducted to determine the prevalence of intestinal parasites in dogs and foxes with an emphasis on Echinococcus spp. A total of 500 fecal samples of dogs and 30 fecal samples of foxes were studied in the summer, autumn, and winter of 2021 in the Zanjan province using the formalin-ethyl acetate concentration technique, followed by multiplex PCR. The overall prevalence of gastrointestinal parasite infection was estimated to be 19.05%. The prevalence was 24.8%, 10.2%, and 26.7% in stray, shelter dogs and foxes, respectively. No parasites were found among pet and guard dog samples. PCR results on Taenidae eggs showed that 2.4% of samples were positive for Echinococcus granulosus and none contained E. multilocularis. Noteworthy is that E. granulosus was identified only in stray dog samples. The higher prevalence of E. granulosus infection in stray dogs in this province emphasizes the importance of monitoring the food sources consumed by these animals.

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.

Past and Present of Diagnosis of Echinococcosis: A Review (1999-2021)

The larval forms of taeniid cestodes belonging to the genus Echinococcus are the source of the zoonotic infection known as echinococcosis. Alveolar and cystic echinococcosis are caused by Echinococcus multilocularis and Echinococcus granulosus (s. s) respectively. It is endemic in several regions of the world. In this systematic review, we describe diagnosis, and the species (human, canids, livestock, and small rodents) affected by cystic (CE) and alveolar echinococcosis (AE). From 1999 to 2021, we searched the online directory through PubMed, SCOPUS, Web of Science, and google scholar. Among the 37,700 records found in the online databases, 187 publications met our eligibility requirements. The majority of investigations employed a range of diagnostic methods, such as ELISA, imaging, copro-PCR, necropsy or arecoline hydrobromide purgation, morphological cestode confirmation, and fecal sieving/flotation to detect and confirm Echinococcus infection. ELISA was the most commonly used method followed by PCR, and imaging. The research team retrieved data describing the incidence or assessment of the diagnostic test for E. multilocularis in humans (N = 99), canids (N = 63), small ruminants (N = 13), large ruminants (N= 3), camel (N= 2), pigs (N=2) and small mammals (N= 5). This study was conducted to explore the diagnostic tools applied to detect echinococcosis in humans as well as animals in prevalent countries, and to report the characteristic of new diagnostic tests for disease surveillance. This systematic review revealed that ELISA (alone or in combination) was the most common method used for disease diagnosis and diagnostic efficacy and prevalence rate increased when recombinant antigens were used. It is highly recommended to use combination protcols such as serological with molecular and imaging technique to diagnose disease. Our study identified scarcity of data of reporting echinococcosis in humans/ animals in low-income or developing countries particularly central Asian countries. Study reports in small rodents indicate their role in disease dissemination but real situation in these host is not refected due to limited number of studies. Even though echinococcosis affects both public health and the domestic animal sector, therefore, it is important to devise new and strengthe implementation of the existing monitoring, judging, and control measures in this estimate.

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.

Epidemiological and molecular studies on Echinococcus granulosus from free-roaming dogs in Southeast Iran

Background and Aim:

Cystic echinococcosis (CE), as a major zoonotic helminth infection, imposes remarkable socioeconomic burden on many endemic countries across the world, including Iran. Due to the high importance of free-roaming dogs in the transmission of CE, epidemiological and molecular studies in this type of hosts are required in the endemic regions. This study aimed to investigate the epidemiology and genotyping of Echinococcusgranulosus isolated from stray dogs in Kerman, Southeast Iran.

Materials and Methods:

Eighty-four samples were isolated from stray dogs in the city and suburbs of Kerman in coordination with the health authorities and the municipality office for rabies control and dog population management. Dog demographic data, including age and sex were collected. The worm was isolated by necropsy and genomic DNA was extracted and partial cytochrome c oxidase subunit 1 gene was amplified using specific primers. Phylogenetic and Templeton-Crandall-Sing (TCS) network analyses were carried out on the sequence data.

Results:

The overall prevalence of CE in the surveyed dogs was 10.7% (9/84 cases). Out of 84 stray dogs, 33 (39.3%) and 51 (60.7%) cases were male and female, respectively. There was not a statistically significant difference between the infection and gender of dogs. However, infection is shown more in dogs under one year of age with a statistically significant difference (p<0.05). The results of molecular studies indicated E. granulosus G1 genotype for all isolates. The high presence of free-roaming dogs in urban and peri-urban areas and high frequency of parasite in this animal is a risk factor for humans in the region. Haplotype sequence analysis on the dog isolates revealed a close relationship with other E. granulosus isolates in Kerman.

Conclusion:

The findings of this study provide evidence-based data about the epidemiological and molecular characteristics of CE in dog definitive hosts of Southeast Iran. Further studies are required to understand the prevalence and parasite genotypes in dogs in Iran.

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.

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.

Multiple zoonotic helminth infections in domestic dogs in a rural area of Khuzestan Province in Iran

Background

Echinococcosis and toxocarosis caused by the genus of Echinococcus and Toxocara spp. are among important helminthic diseases worldwide. Limited data on the prevalence of these parasites persuaded us to determine the prevalence of E. granulosus, E. multilocularis, and T. canis infections in domestic dogs in rural areas of Ahvaz, southwestern Iran. Fecal samples from 167 domestic dogs were examined using both microscopy and PCR techniques. Multiplex PCR was performed for the presence of Echinococcus, and Taenia spp. and single PCR for detection of T. canis and Toxascaris leonina.

Results

The total occurrence of identified parasites was 65 (38.9%). The microscopic examinations showed that 40 (24%), 18 (10.8%), and four (2.4%) of dogs were infected with taeniid-like, ascarid, and both genera eggs, respectively. Echinococcus granulosus was identified in seven (4.2%), Taenia spp. in 29 (17.4%), and mixed infection with both in 11 (6.6%) samples. Sequencing of PCR-positive samples identified E. granulosus s.s. (G1), 18 T. hydatigena (10.8%), five T. multiceps (3%), three T. serialis (1.8%), one T. ovis (0.6%), one Spirometra erinaceieuropaei voucher (0.6%), and two Mesocestoides corti (1.2%). This is the first report of S. erinaceieuropaei voucher and M. corti in dogs in Iran. Nine (5.4%) and 16 (9.6%) dogs showed infection with T. canis and T. leonina, respectively. Two samples showed coinfection with both ascarids.

Conclusions

Several studies have reported echinococcosis and toxocarosis in intermediate hosts from the southwest of Iran; however, this study is the first molecular research on E. granulosus and T. canis in domestic dogs in a rural area of southwestern Iran. Furthermore, issues of soil contamination with dogs’ feces and recent dust storms in Khuzestan may have a role in the spreading of these zoonotic infections to other provinces close to it, and neighboring countries such as Iraq.

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.

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 identification of Echinococcus granulosus strain in stray dogs from Northeastern Iran

Canine echinococcosis, caused by the adult form of taeniid cestodes of the genus Echinococcus is zoonotic and has an epidemiologically worldwide distribution. Dogs infected with E. granulosus are the main source of human hydatidosis, however, there is little information on molecular epidemiology of adult Echinococcus spp. in stray dogs. In the present study, 100 stray dogs (48 males and 52 females, 72 adults and 28 juveniles) were collected from Khorasan Razavi province in Northeastern Iran during October 2013 to December 2014. Thirty-eight (21 males and 17 females, 3 juveniles and 35 adults) out of 100 dogs were infected with E. granulosus. There were no significant differences in prevalence observed between females (43.5%) and males (34.4%), however, the prevalence of E. granulosus, showed a significant increasing trend with increasing host age (p<0.05). Thirty-eight isolated parasites from 38 stray dogs (one parasite per dog) were used for PCR-RFLP analysis of the ITS1 gene. PCR-RFLP analysis showed that all the 38 parasites were E. granulosus G1 genotype (common sheep strain). Five PCR products were sent for sequencing. The results of sequencing were similar to those reported by PCR-RFLP analysis and the presence of E. granulosus G1 genotype (sheep strain) as dominant genotype in dogs were emphasized. The results of this study suggest that the sheep strain occurs in definitive host in Northeastern Iran. Data presented here are expected to be useful for health and educational authorities responsible for designing and implementing effective measures for disease control.

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.

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.

The first morphometric and phylogenetic perspective on molecular epidemiology of Echinococcus granulosus sensu lato in stray dogs in a hyperendemic Middle East focus, northwestern Iran

Background

Hydatidosis is considered to be a neglected cyclo-zoonotic disease in Middle East countries particularly northwestern Iran which is caused by metacestode of tapeworm Echinococcus granulosus sensu lato. Human hydatidosis is a high public health priority in the area, however there is little known from a morphometric and phylogenetic perspective on molecular epidemiology of adult Echinococcus spp. in Iranian stray dogs.

Methods

80 dogs (38 males and 42 females) were collected during June 2013 to April 2014 in northwestern Iran. The isolated parasites from each dog were distinguished by morphometric keys including small, large hook length and blade length. Subsequently, isolates were confirmed by sequencing of mitochondrial cytochrome oxidase subunit 1 gene.

Results

16 (8 males and 8 females) (Prevalence 20 %) out of 80 dogs were infected to genus Echinococcus. With regard to demographic factors, the frequency of parasitism in both male, female adults and their age groups showed no difference (P > 0.05). The phylogenetic analyses of cox1 sequences firmly revealed the 13 sheep strains (G1), one buffalo strain (G3), one camel strain (G6) and one mixed infection. The findings of rostellar hook morphology show an intraspecies variation range among G1 isolates. However, hook measurements in Echinococcus derived from G1 (sheep strain) were not a significant difference from those G6 and G3 strains. Six unique haplotypes were identified containing a high range of diversity (Haplotype diversity 0.873 vs. Nucleotide diversity 0.02).

Conclusions

First presence of camel strain (G6) in this region seems to indicate that potential intermediate hosts play a secondary role in the maintenance of camel-dog biology. Current findings have heightened our knowledge about determination of Echinococcus prevalence, strains of taxonomy and genotypic trait of parasite in Iranian stray dogs which will also help in the development of strategies for monitoring and control of infected stray dogs in the area.

Incidence of Echinococcus granulosus in Domestic Dogs in Palestine as Revealed by Copro-PCR

Hydatidosis or echinococcosisis considered a neglected zoonotic disease despite its high burden in the livestock industry and the high risk of infection by humans in endemic areas. In a cross-sectional study we estimated the copro-Incidence and also genotyped Echinococcus granulosus isolates from domestic dogs using polymerase chain reaction (PCR). Medical archives in nine major hospitals in Palestine were reviewed to determine incidence of E. granulosus infection detected in humans during surgery. Faecal samples were collected from 93 domestic dogs in three districts with the highest number of human cases: Al-Khalil (Hebron), Tubas and Jenin. Genomic DNA was extracted from dog faecal samples and amplified by PCR targeting the repeat DNA sequence (EgG1 Hae III) followed by sequencing of five positive samples. Genotyping was determined by sequencing and BLAST searching of mitochondrial cytochrome c oxidase subunit (CO1). The incidence of E. granulosus infection detected in humans at surgery was 1.2 per 100,000 in the West Bank and 1.0 per 100,000 in Gaza Strip. Seventeen of 93 domestic dogs (18%) were positive, based upon comparison with the Echinococcus DNA control. The five sequenced samples were confirmed to be E. granulosus. Successfully genotyped sample belonged to E.granulosus sensu stricto (formerly G1-G3 complex, sheep strain). For domestic dogs, age group (13-24 months) and sex were identified as two risk factors for contracting E. granulosus. The study identified the high incidence of E. granulosus sensu stricto in dogs in Palestine.

Echinococcosis is a parasitic disease caused by Echinococcus granulosus. The parasite life cycle is shared between a definitive and an intermediate host with humans as accidental hosts. The dog is a main definitive host while sheep is a major intermediate host. The incidence of E. granulosus infection detected in humans at surgery is a commonly used parameter to evaluate the incidence rate of the disease in Palestine. However, this parameter of Echinococcus detection leads to under-reporting of the infection. This study aims to evaluate the incidence of E. granulosus infection in domestic dogs as a potential source of infection to human using molecular methods. Medical archives in nine major hospitals in Palestine were reviewed for E. granulosus infection detected during surgery. Faecal samples were collected from 93 domestic dogs in areas with the highest levels of E. granulosus infection detected in humans at surgery in southern Palestine, including Al-Khalil, and northern Palestine, including Tubas and Jenin districts. The overall incidence rate of E. granulosus infection detected in humans during surgery was 0.9 per 100,000. Around 18% (17/93) of the dogs were infected. Results that E. granulosus was the causative agent were confirmed by sequencing and BLAST search of five positive samples. Genotyping of one sample showed that infection was caused by E. granulosus sensu stricto. The age and sex of dogs were identified as risk factors for contracting infection.

Canine echinococcosis: genetic diversity of Echinococcus granulosus sensu stricto (s.s.) from definitive hosts

Canids, particularly dogs, constitute the major source of cystic echinococcosis (CE) infection to humans, with the majority of cases being caused by Echinococcus granulosus (G1 genotype). Canine echinococcosis is an asymptomatic disease caused by adult tapeworms of E. granulosus sensu lato (s.l.). Information on the population structure and genetic variation of adult E. granulosus is limited. Using sequenced data of the mitochondrial cytochrome c oxidase subunit 1 (cox1) we examined the genetic diversity and population structure of adult tapeworms of E. granulosus (G1 genotype) from canid definitive hosts originating from various geographical regions and compared it to that reported for the larval metacestode stage from sheep and human hosts. Echinococcus granulosus (s.s) was identified from adult tapeworm isolates from Kenya, Libya, Tunisia, Australia, China, Kazakhstan, United Kingdom and Peru, including the first known molecular confirmation from Gaza and the Falkland Islands. Haplotype analysis showed a star-shaped network with a centrally positioned common haplotype previously described for the metacestode stage from sheep and humans, and the neutrality indices indicated population expansion. Low Fst values suggested that populations of adult E. granulosus were not genetically differentiated. Haplotype and nucleotide diversities for E. granulosus isolates from sheep and human origin were twice as high as those reported from canid hosts. This may be related to self-fertilization of E. granulosus and/or to the longevity of the parasite in the respective intermediate and definitive hosts. Improved nuclear single loci are required to investigate the discrepancies in genetic variation seen in this study.

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.

Genetic diversity of Echinococcus granulosus in center of Iran

Hydatid cyst caused by Echinococcus granulosus is one of the most important parasitic diseases around the world and many countries in Asia, including Iran, are involved with this infection. This disease can cause high mortality in humans as well as economic losses in livestock. To date, several molecular methods have been used to determine the genetic diversity of E. granulosus. So far, identification of E. granulosus using real-time PCR fluorescence-based quantitative assays has not been studied worldwide, also in Iran. Therefore, the aim of this study was to investigate the genetic diversity of E. granulosus from center of Iran using real-time PCR method. A total of 71 hydatid cysts were collected from infected sheep, goat, and cattle slaughtered in Isfahan, Iran during 2013. DNA was extracted from protoscolices and/or germinal layers from each individual cyst and used as template to amplify the mitochondrial cytochrome c oxidase subunit 1 gene (cox1) (420 bp). Five cattle isolates out of 71 isolates were sterile and excluded from further investigation. Overall, of 66 isolates, partial sequences of the cox1 gene of E. granulosus indicated the presence of genotypes G1 in 49 isolates (74.2%), G3 in 15 isolates (22.7%), and G6 in 2 isolates (3.0%) in infected intermediate hosts. Sixteen sequences of G1 genotype had microgenetic variants, and they were compared to the original sequence of cox1. However, isolates identified as G3 and G6 genotypes were completely consistent with original sequences. G1 genotype in livestock was the dominant genotype in Isfahan region, Iran.

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.