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

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.

Genetic diversity of Echinococcus spp. in wild carnivorous animals in Kazakhstan

Background and Aim:

The study of Echinococcus infection among farm animals in Kazakhstan was carried out to monitor the invasion among livestock and map the data obtained. Unfortunately, there are only partial data on the study of echinococcosis among wild carnivores in Kazakhstan, which makes it difficult to conduct a comparative analysis of the epidemiological situation among wild animals. The present study aimed to estimate the genetic diversity of Echinococcus spp. (Leuckart, 1863) in Kazakhstan based on sequence analysis of cytochrome c oxidase subunit 1 (cox1) and dehydrogenase subunit 1 (nad1) of worms isolated from wild carnivorous animals wolf (Canis lupus), red fox (Vulpes vulpes) and corsac (Vulpes corsac).

Materials and Methods:

DNA from parasite tissue was used as a template for the amplification of the two mitochondrial genes cox1 and nad1. Sequencing was performed according to the manual for the Seq Studio Genetic Analyzer. The multiple alignments of obtained sequences were performed using the ClustalW algorithm in Mega (v.11) software. Alignments were exported as a Nexus extension and used as input for TCS v1.21 for the identification of haplotypes. The phylogenetic analysis was constructed according to the neighbor-joining method using Mega (v.11) software.

Results:

Analysis of the extensiveness of echinococcosis invasion showed that 6.3% were wolves, 18.2% were corsacs, and 85% were foxes. In total, 159 adults of Echinococcus spp. from the three species of animals in different parts of Kazakhstan were analyzed, and 17 individual biological samples were successfully sequenced. Sequence analysis of cox1 and nad1 genes revealed two types of echinococcosis – Echinococcus granulosus in red foxes and wolves, and Echinococcus multilocularis in corsacs. Sequencing of a portion of the mitochondrial genome made it possible to determine seven haplotypes of the pathogen in the studied samples of E. granulosus. Molecular analysis of cox1 and nad1 genes of E. multilocularis revealed three new haplotypes, which have significant variability compared with other studied Asian haplotypes.

Conclusion:

This study made it possible to fill the gaps in understanding the localization of the foci of the spread of the echinococcosis pathogen among the main wild carnivores and to determine the species reservoir of the pathogen in the greater territory of Kazakhstan.

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.

MicroRNAs in helminth parasites: a systematic review

BACKGROUND

MicroRNAs (miRNAs) are about 22-nucleotide, small, non-coding RNAs that control gene expression post-transcriptionally. Helminth parasites usually express a unique repertoire of genes, including miRNAs, across different developmental stages with subtle regulatory mechanisms.

OBJECTIVE

There is a necessity to investigate the involvement of miRNAs in the development of parasites, host-parasite interaction, immune evasion and their abilities to govern infection in hosts. miRNAs present in helminth parasites have been summarized in the current systematic review (SR).

METHODS

Electronic databases, including PubMed, Scopus, ProQuest, Embase, and Google Scholar search engine, were searched to identify helminth miRNA studies published from February 1993 till December 2019. Only the published articles in English were included in the study.

RESULTS

A total of 1769 articles were preliminarily recorded. Following the strict inclusion and exclusion criteria, 105 studies were included in this SR. Most of these studies focused on the identification of miRNAs in helminth parasites and/or probing of differentially expressed host miRNA profiles in specific relevant tissues, while 12 studies aimed to detect parasite-derived miRNAs in host circulating system and 15 studies characterized extracellular vesicles (EV)-derived miRNAs secreted by parasites.

CONCLUSION

In the current SR, information regarding all miRNAs expressed in helminth parasites has been comprehensively provided and the utility of helminth parasites-derived miRNAs in diagnosis and control of parasitic infections has been discussed. Furthermore, functional studies on helminth-derived miRNAs have also been presented.

Expression analysis of circulating miR-146a and miR-155 as novel biomarkers related to effective immune responses in human cystic echinococcosis

Cystic echinococcosis, an important zoonotic disease, is caused by Echinococcus granulosus. MicroRNAs are a small group of single-stranded noncoding RNAs, which play an effective role in biological processes. This study aimed at comparing the expression levels of miR-146a and miR-155 in the plasma of patients with hydatidosis and healthy individuals. A group of 20 patients with hydatid cyst formed a study group and 20 healthy individuals with no known chronic diseases formed a control group. Plasma samples were collected from hydatidosis patients as well as sex- and age-matched healthy volunteers. After that, RNA extraction and cDNA synthesis were done and the expression levels of miR-146a and miR-155 were determined by quantitative real-time polymerase chain reaction (PCR) for both groups. The results indicated that the level of miR-146a increased in all patients with hydatidosis compared to the control group. Also, the level of miR-155 increased in all hydatidosis patients, but no correlation was observed in the level of miR-155 between the two groups. The results also revealed that miR-146a and miR-155 upregulation in the plasma leads to the development of novel biomarkers for echinococcosis. One of the reasons for the increase of miRNAs in hydatidosis may be their role in modulating the immune system. These miRNAs are likely to be considered as one of the most important biomarkers in determining the severity of hydatidosis.

Molecular characterization of sheep and human isolates of Echinococcus granulosus from temperate region of India

The aim of the present study was to investigate Echinococcus granulosus genotypes in the Kashmir valley. A total of 2,100 sheep and human patients were screened for the presence of hydatidosis. Total 87 isolates were collected, 85 from sheep and 2 isolates from human beings. The rDNA-ITS1 fragment were amplified with BD1 / 4S primers. In addition, fragments of genes coding for ITS1 were sequenced. The length of amplified fragment for all isolated samples with sheep origin was 1,000 bp and with human origin was between 1,000 bp and 1,100 bp. The products on digestion with restriction enzymes Rsa 1, Alu 1, Msp 1 yielded identical fragments, 300 and 700 bp in sheep and 325 and 700 bp in humans. Intact 1000 bp fragment was observed with Taq 1. The molecular findings reveal that sheep strain (G1) is the predominant genotype in sheep and humans in Kashmir valley.

Therapeutic efficacy of nanocompounds in the treatment of cystic and alveolar echinococcoses: challenges and future prospects

Echinococcus granulosus sensu lato and E. multilocularis are the causative agents of life-threatening cystic and alveolar echinococcoses (CE and AE), respectively, which lead to serious public health concerns across the globe. Benzimidazoles (BMZs) are the drugs of choice for the treatment of human CE and AE. Presently, the chemotherapeutic failures of BMZs against CE and AE are caused by their low aqueous solubility, poor absorption, and consequently their erratic bioavailability. Among the BMZ compounds used for CE/AE treatment, albendazole (ABZ) and mebendazole (MBZ) are the only drugs licensed for human use. Nevertheless, the administration of these BMZs for a long period of time leads to undesirable adverse effects. Therefore, there is an urgent need for designing new formulations of BMZs with increased bioavailability. To bridge these therapeutic gaps, nanoparticle enantiomers of ABZ and drug delivery systems based on nanostructured entities currently provide an interesting new formulation of already existing drugs to improve the pharmacokinetic effects of BMZs. This study provides an overview of the tested nanocompounds against E. granulosus and E. multilocularis, including their effective dose, type of nanoparticles (NPs), assay setting, and therapeutic outcomes. This review suggests that BMZ derivatives loaded in NPs can significantly improve the scolicidal and cysticidal activities compared with single BMZ. Moreover, BMZ-loaded polymeric NPs show a tendency to increase mortality rate against protoscoleces and microcysts compared with metallic formulations, nanoemulsions, lipid nanocapsules, solid lipid NPs, liposomes, and nanocrystals. In the future, the use of the newly structured entities, attained by bridging ligands to the modified surface of NPs, as well as the electromagnetically produced nanodrugs could be helpful for developing fine-tuned formulations as an alternative to the already existing drugs against these neglected parasitic infections.

Prevalence and Molecular Characterization of Echinococcus granulosus Sensu Stricto in Northern Xinjiang, China

Echinococcus granulosus is an important zoonotic parasite globally causing cystic echinococcosis (CE) in humans and animals. In this study, prevalence of CE and variation of cox1 gene sequence were analyzed with isolates E. granulosus collected from different areas in northern Xinjiang, China. The survey showed that 3.5% of sheep and 4.1% of cattle were infected with CE. Fragment of cox1 was amplified from all the positive sheep and cattle samples by PCR. In addition, 26 positive samples across the 4 areas were included. The isolates were all E. granulosus sensu stricto (s.s.) containing 15 haplotypes (Hap1-15), and clustered into 2 genotypes, G1 (90.1%, 91/101) and G3 (9.9%, 10/101). Hap1 was the most common haplotype (48.5%, 49/101). Hap9 were found in humans samples, indicating that sheep and cattle reservoir human CE. It is indicate that E. granulosus may impact on control of CE in livestock and humans in the region.

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.

The potential role of toll-like receptor 4 Asp299Gly polymorphism and its association with recurrent cystic echinococcosis in postoperative patients

The study of pathogenesis mechanisms of larval stages in the Taeniidae has recently focused on host genetic factors, particularly toll-like receptor (TLR) variations. However, the potential role of TLR4 polymorphism in hydatidosis has not yet been sufficiently elucidated in postoperative patients. In this case-control investigation, 80 patients from Iran, including 40 with acute hydatidosis (AH) and 40 with recurrent hydatidosis (RH), and 80 ethnically matched controls were evaluated from February 2015 to February 2017. Hydatidosis patients were confirmed using radiological, immunological, and histopathological examinations. Genotyping of Asp299Gly and Thr399Ile of TLR4 single-nucleotide polymorphisms was determined by restriction fragment length polymorphism, sequencing, and phylogenetic strategies. The heterozygous mutant-type TLR4 Asp299Gly genotype indicated a tendency to be associated with the occurrence of RH (P = 0.060) and conferred a 3-fold risk for susceptibility. There was no difference in genotype frequency of Asp299Gly between patients with AH and healthy controls (P = 0.42; OR, 1.82; 95% CI, 0.11-30.1%). Interestingly, a frequency of the G allele (12%: Gly) was observed to be a risk factor for susceptibility to RH patients (P = 0.050; OR, 7.08; 95% CI, 0.97-51.5%). A relative genetic variability of TLR4 Asp299Gly was found in RH patients (haplotype diversity: 0.700) compared to AH patients and healthy controls (Hd: 0.000). The Asp299Gly genotype was dominantly identified in patients with hepatic hydatid cysts. The TLR4 Thr399Ile codon was not detected except in a patient with a pulmonary hydatid cyst. The current findings enhance our knowledge regarding the TLR4 Asp299Gly polymorphism potentially leading to the development of RH, by skewing the immune system towards a Th2 response. Identification of the Asp299Gly codon may be a diagnostic hallmark in RH patients who have undergone unsuccessful postoperative intervention. However, further studies with a higher case number are needed on ethnic population from various geographic regions, in order to confirm this hypothesis.

Two haplotype clusters of Echinococcus granulosus sensu stricto in northern Iraq (Kurdistan region) support the hypothesis of a parasite cradle in the Middle East

Human cystic echinococcosis (CE) caused by Echinococcus granulosus s.s. is a major public health problem in Iraqi Kurdistan with a reported surgical incidence of 6.3 per 100,000 Arbil inhabitants. A total of 125 Echinococcus isolates retrieved from sheep, goats and cattle were used in this study. Our aim was to determine species/genotypes infecting livestock in Iraqi Kurdistan and examine intraspecific variation and population structure of Echinococcus granulosus s.s. in this region and relate it to that of other regions worldwide. Using nucleotide sequences of the mitochondrial cytochrome c oxidase subunit 1 (cox 1) we identified E. granulosus s.s. as the cause of hydatidosis in all examined animals. The haplotype network displayed a double-clustered topology with two main E. granulosus s.s. haplotypes, (KU05) and (KU33). The 'founder' haplotype (KU05) confirmed the presence of a common lineage of non-genetically differentiated populations as inferred by the low non-significant fixation index values. Overall diversity and neutrality indices indicated demographic expansion. We used E. granulosus s.s. nucleotide sequences from GenBank to draw haplotype networks for the Middle East (Iran, Jordan and Turkey), Europe (Albania, Greece, Italy, Romania and Spain), China, Mongolia, Russia, South America (Argentina, Brazil, Chile and Mexico) and Tunisia. Networks with two haplotype clusters like that reported here for Iraqi Kurdistan were seen for the Middle East, Europe, Mongolia, Russia and Tunisia using both 827bp and 1609bp cox1 nucleotide sequences, whereas a star-like network was observed for China and South America. We hypothesize that the double clustering seen at what is generally assumed to be the cradle of domestication may have emerged independently and dispersed from the Middle East to other regions and that haplotype (KU33) may be the main haplotype within a second cluster in the Middle East from where it has spread into Europe, Mongolia, Russia and North Africa. Further studies using metacestodes of human origin are required to investigate the biological importance of E. granulosus s.s. haplotypes/clusters and their association, if any with clinical manifestations of CE infection.

Molecular and Morphological Characterizations of Echinococcus granulosus from Human and Animal Isolates in Kashan, Markazi Province, Iran

BACKGROUND

One of the most important zoonotic helminths in the world is known as Echinococcus granulosus. Different strains of the E. granulosus have been described based on morphological and molecular characterizations, however, there is limited information regarding the characteristics of the phenotypes and genotypes of E. granulosus in Iran.

METHODS

The present study was prepared to evaluate the phenotypic and genotypic diversity of E. granulosus isolates collected from human, goat, sheep, and cattle based on 19 standard morphometric parameters and mitochondrial and nuclear genes (CO1, ND1, and ITS1) in Kashan, Markazi Province, Iran during 2013-2014.

RESULTS

The biometric analysis for the 19 characters revealed that the 19 morphometric values of cattle isolates were exceptionally higher than human, goat, and sheep isolates (P<0.05). Molecular analysis confirms the morphological findings. Phylogenic analysis of the CO1, NAD1 and ITS1 genes for all isolates, independent of the host, revealed that the common sheep strain (G1) is traveling among livestock in Kashan and the strains are highly adapted to goats, cattle, sheep, and humans.

CONCLUSION

Both morphological and molecular results of this study indicated that the only genotype G1 of E. granulosus travels between humans and other intermediate hosts of this parasite in the area study.

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.