A molecular phylogeny of the genus Echinococcus inferred from complete mitochondrial genomes

Effective Laboratory Diagnosis of Parasitic Infections of the Gastrointestinal Tract: Where, When, How, and What Should We Look For?

(1) Introduction: Gastrointestinal parasites (GIPs) are one of the most common causes of disease in the world. Clinical diagnosis of most parasitic diseases is difficult because they do not produce characteristic symptoms. (2) Methods: The PubMed, Science Direct, and Wiley Online Library medical databases were reviewed using the following phrases: "parasitic infections and diagnostics", "intestinal parasites", "gastrointestinal parasites", "parasitic infections and diagnostics", and their combinations. (3) Results and Conclusions: Correct diagnosis of GIP involves determining the presence of a parasite and establishing a relationship between parasite invasion and disease symptoms. The diagnostic process should consider the possibility of the coexistence of infection with several parasites at the same time. In such a situation, diagnostics should be planned with consideration of their frequency in each population and the local epidemiological situation. The importance of the proper interpretation of laboratory test results, based on good knowledge of the biology of the parasite, should be emphasized. The presence of the parasite may not be causally related to the disease symptoms. Due to wide access to laboratories, patients often decide to perform tests themselves without clinical justification. Research is carried out using various methods which are often unreliable. This review briefly covers current laboratory methods for diagnosing the most common gastrointestinal parasitic diseases in Europe. In particular, we provide useful information on the following aspects: (i) what to look for and where to look for it (suitability of feces, blood, duodenal contents, material taken from endoscopy or biopsy, tissue samples, and locations for searching for eggs, cysts, parasites, parasite genetic material, and characteristics of immune responses indicating parasitic infections); (ii) when material should be collected for diagnosis and/or to check the effectiveness of treatment; (iii) how-that is, by what methods-laboratory diagnostics should be carried out. Here, the advantages and disadvantages of direct and indirect methods of detecting parasites will be discussed. False-positive or false-negative results are a problem facing many tests. Available tests have different sensitivities and specificities. Therefore, especially in doubtful situations, tests for the presence of the pathogen should be performed using various available methods. It is important that the methods used make it possible to distinguish an active infection from a past infection. Finally, we present laboratory "case reports", in which we will discuss the diagnostic procedure that allows for the successful identification of parasites. Additionally, we briefly present the possibilities of using artificial intelligence to improve the effectiveness of diagnosing parasitic diseases.

Mitogenome-Based Phylogeny with Divergence Time Estimates Revealed the Presence of Cryptic Species within Heptageniidae (Insecta, Ephemeroptera)

Heptageniidae are known for their flat heads and bodies and are divided into three subfamilies. Despite the extensive diversity within this group and considerable efforts made to understand their evolutionary history, the internal classifications and origin time of Heptageniidae remains controversial. In this study, we newly sequenced 17 complete mitogenomes of Heptageniidae to reconstruct their phylogenetic positions within this family. Because of the ambiguous time of origin, our study also estimated the divergence time within Heptageniidae based on five fossil calibration points. The results of BI and ML trees all highly supported the monophyly of Heptageniidae and three subfamilies. The phylogenetic relationship of Rhithrogeninae + (Ecdyonurinae + Heptageniinae) was also recovered. The divergence time showed that Heptageniidae originated from 164.38 Mya (95% HPD, 150.23-181.53 Mya) in the mid-Jurassic, and Rhithrogeninae originated from 95.54 Mya (95% HPD, 73.86-120.19 Mya) in the mid-Cretaceous. Ecdyonurinae and Heptageniinae began to diverge at 90.08 Mya (95% HPD, 68.81-113.16 Mya) in the middle Cretaceous. After morphological identification, analysis of the mitogenome's composition, genetic distance calculation, phylogenetic analysis, and divergence time calculation, we suggest that two different populations of Epeorus montanus collected from Aksu, Xinjiang Uygur Autonomous Region (40°16' N, 80°26' E) and Xinyuan, Xinjiang Uygur Autonomous Region (43°20' N, 83°43' E) in China are cryptic species of E. montanus, but further detailed information on their morphological characteristics is needed to fully identify them.

Challenging the phylogenetic relationships among Echinococcus multilocularis isolates from main endemic areas

Alveolar echinococcosis (AE) is a rare but severe disease that affects more than 18,000 people worldwide per year. The complete sequencing of the mitochondrial genome of Echinococcus multilocularis has made it possible to study the genetic diversity of the parasite and its spatial and temporal evolution. We amplified the whole mitochondrial genome by PCR, using one uniplex and two multiplex reactions to cover the 13,738 bp of the mitogenome, and then sequenced the amplicons with Illumina technology. In total, 113 samples from Europe, Asia, the Arctic and North America were analyzed. Three major haplogroups were found: HG1, which clustered samples from Alaska (including Saint-Lawrence Island), Yakutia (Russia) and Svalbard; HG2, with samples from Asia, North America and Europe; and HG3, subdivided into three micro-haplogroups. HG3a included samples from North America and Europe, whereas HG3b and HG3c only include samples from Europe. In France, HG3a included samples from patients more recently diagnosed in a region outside the historical endemic area. A fourth putative haplogroup, HG4, was represented by only one isolate from Olkhon Island (Russia). The increased discriminatory power of the complete sequencing of the E. multilocularis mitogenome has made it possible to highlight four distinct geographical clusters, one being divided into three micro-haplogroups in France.

Use of the EmsB microsatellite-based next generation sequencing for genotyping of Echinococcus granulosus sensu lato in hydatid cyst tissue samples from animals and humans

Echinococcus granulosus (Batsch, 1786), a cestode of the Teniidae family, causes human cystic echinococcosis (CE) also known as hydatid disease. Echinococcus granulosus sensu lato includes the G1, G3, G4, G5, G6/7 and G8/10 genotypes which are known to cause human CE. This study aimed to differentiate genotypes of E. granulosus s.l. complex by employing EmsB, a tandemly repeated multilocus microsatellite, using next-generation sequencing (MIC-NGS). Human and animal histopathology-confirmed hydatid cyst tissue samples and reference DNA samples of E. granulosus G1, G3, G4, G5, G6/7 and G10 underwent MIC-NGS assay with custom primers amplifying a 151 bp EmsB DNA fragment. NGS data were analysed using online Galaxy analysis pipeline, a phylogenetic tree was constructed by MEGA software, and haplotype networking was performed with PopArt 1.7. All sixty samples (49 from animals and 11 from humans) included were successfully identified and genotyped with a 100 % success rate. The study showed improved discrimination power to distinguish all study samples including closely related E. granulosus s.s. genotypes G1-G3. The maximum likelihood tree reaffirmed the monophyly of E. granulosus s.l. The median-joining haplotype networking revealed 12 distinct haplotypes. In conclusion, MIC-NGS assay was shown to be sensitive, specific and simple to apply to clinical samples offering a powerful discriminatory tool for the genotyping of E. granulosus s.l.

Untargeted metabolomics to discriminate liver and lung hydatid cysts: Importance of metabolites involved in the immune response

The Echinococcus granulosus sensu lato species complex is responsible for the neglected zoonotic disease known as cystic echinococcosis (CE). Humans and livestock are infected via fecal-oral transmission. CE remains prevalent in Western China, Central Asia, South America, Eastern Africa, and the Mediterranean. Approximately one million individuals worldwide are affected, influencing veterinary and public health, as well as social and economic matters. The infection causes slow-growing cysts, predominantly in the liver and lungs, but can also develop in other organs. The exact progression of these cysts is uncertain. This study aimed to understand the survival mechanisms of liver and lung CE cysts from cattle by determining their metabolite profiles through metabolomics and multivariate statistical analyses. Non-targeted metabolomic approaches were conducted using quadrupole-time-of-flight liquid chromatography/mass spectrometry (LC-QTOF-MS) to distinguish between liver and lung CE cysts. Data processing to extract the peaks on complex chromatograms was performed using XCMS. PCA and OPLS-DA plots obtained through multiple statistical analyses showed interactions of metabolites within and between groups. Metabolites such as glutathione, prostaglandin, folic acid, and cortisol that cause different immunological reactions have been identified both in liver and lung hydatid cysts, but in different ratios. Considering the differences in the metabolomic profiles of the liver and lung cysts determined in the present study will contribute research to enlighten the nature of the cyst and develop specific therapeutic strategies.

Advances in Detecting Cystic Echinococcosis in Intermediate Hosts and New Diagnostic Tools: A Literature Review

Cystic echinococcosis (CE) is a zoonotic disease affecting humans and animals. Despite a lack of clarity about many details of parasite-intermediate host interactions, the nature of the immune responses triggered by hydatid infection has revealed new perspectives. This study discusses the latest advances in elucidating the immunologic mechanism of echinococcosis and its detection and potential approaches to enhance serodiagnosis accuracy. Moreover, nanobiosensors have been evaluated according to their potential to improve treatment efficiency and aid in an early diagnosis of cystic echinococcosis. The serum of an intermediate host can diagnose CE by analyzing antibodies induced by Echinococcus granulosus. Among the most notable features of this method are its noninvasive ability and high sensitivity, both of which make it an excellent tool for clinical diagnosis. Several serological tests, including ELISAs and immunoblotting, can detect these antibodies to assess the disease's state and determine the treatment outcome. A thorough understanding of what cross-reactivity means and the stage of the disease are crucial to interpreting serological results. Nanobiosensors have also proven better than conventional biosensors in detecting hydatid cysts. Additionally, they are highly sensitive and versatile when detecting specific biomarkers, improving diagnostic accuracy. These immunomodulatory molecules, induced by E. granulosus, are a good candidate for diagnosing cystic echinococcosis because they alter intermediate host immune responses. Hydatid cyst detection is also enhanced through nanobiosensors, which provide better accuracy.

Comparative Mitogenome of Phylogenetic Relationships and Divergence Time Analysis within Potamanthidae (Insecta: Ephemeroptera)

Potamanthidae belongs to the superfamily Ephemeroidea but has no complete mt genome released in the NCBI (except for two unchecked and one partial mt genome). Since the sister clade to Potamanthidae has always been controversial, we sequenced seven mt genomes of Potamanthidae (two species from Rhoenanthus and five species from Potamanthus) in order to rebuild the phylogenetic relationships of Potamanthidae in this study. The divergence time of Potamanthidae was also investigated by utilizing five fossil calibration points because of the indeterminate origin time. In addition, because Rhoenanthus coreanus and Potamanthus luteus are always in low-temperature environments, we aimed to explore whether these two species were under positive selection at the mt genome level. Amongst the 13 PCGs, CGA was used as the start codon in COX1, whereas other genes conformed to initiating with an ATN start codon. From this analysis, UUA (L), AUU (I), and UUU (F) had the highest usage. Furthermore, the DHU arm was absent in the secondary structure of S1 in all species. By combining the 13 PCGs and 2 rRNAs, we reconstructed the phylogenetic relationship of Potamanthidae within Ephemeroptera. The monophyly of Potamanthidae and the monophyly of Rhoenanthus and Potamanthus were supported in the results. The phylogenetic relationship of Potamanthidae + (Ephemeridae + Polymitarcyidae) was also recovered with a high prior probability. The divergence times of Potamanthidae were traced to be 90.44 Mya (95% HPD, 62.80-121.74 Mya), and the divergence times of Rhoenanthus and Potamanthus originated at approximately 64.77 Mya (95% HPD, 43.82-88.68 Mya), thus belonging to the late Pliocene Epoch or early Miocene Epoch. In addition, the data indicated that R. coreanus was under negative selection and that ATP8 and ND2 in Potamanthidae had a high evolutionary rate.

A filarial parasite potentially associated with the health burden on domestic chickens in Japan

Chickens in free-range environments are at risk of exposure to various pathogens, such as filarioids transmitted via hematophagous vectors. However, the study of filarioids in poultry has been largely neglected compared to the extensive studies focused on viruses, bacteria, and protozoa. Here, we performed histological and molecular investigations of the filarioids detected in domestic chickens from two different flocks in Hiroshima Prefecture, Japan. In the first case, adult worms were present in the pulmonary artery and right ventricle, and microfilariae were present in multiple organs of deceased chickens. In the second case, similar filarioids were detected in the organs and blood of one necropsied layer. Phylogenetic analysis using 18S rRNA gene fragments positioned the filarioid in the same clade as that of Onchocercidae sp., previously identified in a deceased chicken from Chiba Prefecture, Japan, that is located 500 km away from Hiroshima Prefecture. Based on 28S rRNA and mitochondrial COI gene fragments, the filarioid was positioned distinctly from previously reported genera of avian filarioids. These results suggest that the filarioids are potentially associated with the health burden on domestic chickens and belong to the genus Paronchocerca. Furthermore, we developed a nested PCR assay targeting mitochondrial COI and detected the parasite DNA from the biting midge Culicoides arakawae captured near the flock, suggesting that it serves as a vector. Our findings fill the knowledge gap regarding avian filarioids, laying the groundwork for future studies examining the epidemiology, life cycle, and species diversity of this neglected parasite group.

A new species of Versteria (Cestoda: Taeniidae) parasitizing Neogale vison and Lontra canadensis (Carnivora: Mustelidae) from Western Canada

Via molecular and morphological analyses, we describe adult specimens of a new species of Versteria (Cestoda: Taeniidae) infecting mink and river otter (Carnivora: Mustelidae) in Western Canada, as well as larval forms from muskrat and mink. These sequences closely matched those reported from adult specimens from Colorado and Oregon, as well as larval infections in humans and a captive orangutan. We describe here a new species from British Columbia and Alberta (Canada), Versteria rafei n. sp., based upon morphological diagnostic characteristics and genetic distance and phylogeny. Versteria rafei n. sp. differs from the three other described species of the genus in the smaller scolex and cirrus sac. It also differs from V. mustelae (Eurasia) and V. cuja (South America) by having an armed cirrus, which is covered in hair-like bristles, and in the shape of its hooks, with a long thorn-like blade, and short or long handle (vs. a short sharply curved blade and no difference in handle size in previously described species). The poorly known V. brachyacantha (Central Africa) also has an armed cirrus and similarly shaped hooks. However, it differs from the new species in the number and size of hooks. Phylogenetic analysis of the cox1 and nad1 mitochondrial regions showed that our specimens clustered with isolates from undescribed adults and larval infections in North America, and separate from V. cuja, confirming them to be a distinct species from the American Clade.

Prevalence of cystic echinococcosis among livestock in pastoral and agro-pastoral areas in Uganda

Cystic echinococcosis (CE) remains a significant challenge in Uganda with precise status largely undocumented in most communities. To determine CE prevalence, post-mortem examination was done on 14 937 livestock (5873 goats, 1377 sheep, 3726 zebu cattle and 3054 Ankole cattle) slaughtered in abattoirs in the districts of Moroto in Karamoja region, Kumi in Teso region and Nakasongola and Luwero in Buganda region. The overall CE prevalence was 21.9% in sheep, 15.2% in zebu cattle, 5.5% in goats and 2.1% in Ankole cattle. Moroto district had a higher prevalence of CE than other districts with 31.3% in zebu cattle, sheep 28%, goats 29.1% and (0%) in Ankole cattle. On organ locations, the lungs were the most affected in all livestock in all the study areas. Considering cyst fertility, 33.9, 1.7 and 6.4% of Ankole cattle, sheep and zebu cattle respectively had fertile cysts in the liver while 4.5% of goats and 4% Ankole cattle had fertile cysts in the lungs. In conclusion, CE is widespread and occurs among cattle, sheep and goats in pastoral and agro-pastoral areas in Uganda. Therefore, there is an urgent need to create awareness among the communities on role of livestock in CE epidemiology and transmission.

High genetic diversity of Echinococcus canadensis G10 in northeastern Asia: is it the region of origin?

Echinococcus canadensis consists of 4 genotypes: G6, G7, G8 and G10. While the first 2 predominantly infect domestic animals, the latter are sylvatic in nature involving mainly wolves and cervids as hosts and can be found in the northern temperate to Arctic latitudes. This circumstance makes the acquisition of sample material difficult, and little information is known about their genetic structure. The majority of specimens analysed to date have been from the European region, comparatively few from northeast Asia and Alaska. In the current study, Echinococcus spp. from wolves and intermediate hosts from the Republic of Sakha in eastern Russia were examined. Echinococcus canadensis G10 was identified in 15 wolves and 4 cervid intermediate hosts. Complete mitochondrial cytochrome c oxidase subunit 1 (cox1) sequences were obtained from 42 worm and cyst specimens from Sakha and, for comparison, from an additional 13 G10 cysts from Finland. For comparative analyses of the genetic diversity of G10 of European and Asian origin, all available cox1 sequences from GenBank were included, increasing the number of sequences to 99. The diversity found in northeast Asia was by far higher than in Europe, suggesting that the geographic origin of E. canadensis (at least of G10) might be northeast Asia.

Establishment of a secondary infection laboratory model of Echinococcus shiquicus metacestode using BALB/c mice and Mongolian jirds (Meriones unguiculatus)

Echinococcus shiquicus is peculiar to the Qinghai–Tibet plateau of China. Research on this parasite has mainly focused on epidemiological surveys and life cycle studies. So far, limited laboratory studies have been reported. Here, experimental infection of E. shiquicus metacestode in BALB/c mice and Mongolian jirds (Meriones unguiculatus) was carried out to establish alternative laboratory animal models. Intraperitoneal inoculation of metacestode material containing protoscoleces (PSCs) obtained from infected plateau pikas were conducted on BALB/c mice. Furthermore, metacestode material without PSCs deriving from infected BALB/c mice was intraperitoneally inoculated to Mongolian jirds. Experimental animals were dissected for macroscopic and histopathological examination. The growth of cysts in BALB/c mice was infiltrative, and they invaded the murine entire body. Most of the metacestode cysts were multicystic, but a few were unilocular. The cysts contained sterile vesicles, which had no PSCs. The metacestode materials were able to successfully infect new mice. In the jirds model, E. shiquicus cysts were typically formed freely in the peritoneal cavity; the majority of these cysts were free while a small portion adhered loosely to nearby organs. The proportion of fertile cysts was high, and contained many PSCs. The PSCs produced in Mongolian jirds also successfully infected new ones, which confirms that jirds can serve as an alternative experimental intermediate host. In conclusion, a laboratory animal infection was successfully established for E. shiquicus using BALB/c mice and Mongolian jirds. These results provide new models for the in-depth study of Echinococcus metacestode survival strategy, host interactions and immune escape mechanism.

Establishment and application of unbiased in vitro drug screening assays for the identification of compounds against Echinococcus granulosus sensu stricto

Echinococcus multilocularis and E. granulosus s.l. are the causative agents of alveolar and cystic echinococcosis, respectively. Drug treatment options for these severe and neglected diseases are limited to benzimidazoles, which are not always efficacious, and adverse side effects are reported. Thus, novel and improved treatments are needed. In this study, the previously established platform for E. multilocularis in vitro drug assessment was adapted to E. granulosus s.s. In a first step, in vitro culture protocols for E. granulosus s.s. were established. This resulted in the generation of large amounts of E. granulosus s.s. metacestode vesicles as well as germinal layer (GL) cells. In vitro culture of these cells formed metacestode vesicles displaying structural characteristics of metacestode cysts generated in vivo. Next, drug susceptibilities of E. multilocularis and E. granulosus s.s. protoscoleces, metacestode vesicles and GL cells were comparatively assessed employing established assays including (i) metacestode vesicle damage marker release assay, (ii) metacestode vesicle viability assay, (iii) GL cell viability assay, and (iv) protoscolex motility assay. The standard drugs albendazole, buparvaquone, mefloquine, MMV665807, monepantel, niclosamide and nitazoxanide were included. MMV665807, niclosamide and nitazoxanide were active against the parasite in all four assays against both species. MMV665807 and monepantel were significantly more active against E. multilocularis metacestode vesicles, while albendazole and nitazoxanide were significantly more active against E. multilocularis GL cells. Albendazole displayed activity against E. multilocularis GL cells, but no effects were seen in albendazole-treated E. granulosus s.s. GL cells within five days. Treatment of protoscoleces with albendazole and monepantel had no impact on motility. Similar results were observed for both species with praziquantel and its enantiomers against protoscoleces. In conclusion, in vitro culture techniques and drug screening methods previously established for E. multilocularis were successfully implemented for E. granulosus s.s., allowing comparisons of drug efficacy between the two species. This study provides in vitro culture techniques for the reliable generation of E. granulosus s.s. metacestode vesicles and GL cell cultures and describes the validation of standardized in vitro drug screening methods for E. granulosus s.s.

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

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

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

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

Complete mitochondrial exploration of Echinococcus multilocularis from French alveolar echinococcosis patients

Alveolar echinococcosis (AE) is a parasitosis that is expanding worldwide, including in Europe. The development of genotypic markers is essential to follow its spatiotemporal evolution. Sequencing of the commonly used mitochondrial genes cob, cox1, and nad2 shows low discriminatory power, and analysis of the microsatellite marker EmsB does not allow nucleotide sequence analysis. We aimed to develop a new method for the genotyping of Echinococcus multilocularis based on whole mitochondrial genome (mitogenome) sequencing, to determine the genetic diversity among 30 human visceral samples from French patients, and compare this method with those currently in use. Sequencing of the whole mitochondrial genome was carried out after amplification by PCR, using one uniplex and two multiplex reactions to cover the 13,738 bp of the mitogenome, combined with Illumina technology. Thirty complete mitogenome sequences were obtained from AE lesions. One showed strong identity with Asian genotypes (99.98% identity) in a patient who had travelled to China. The other 29 mitogenomes could be differentiated into 13 haplotypes, showing higher haplotype and nucleotide diversity than when using the cob, cox1, and nad2 gene sequences alone. The mitochondrial genotyping data and EmsB profiles did not overlap, probably because one method uses the mitochondrial genome and the other the nuclear genome. The pairwise fixation index (F_st) value between individuals living inside and those living outside the endemic area was high (F_st = 0.222, P = 0.002). This is consistent with the hypothesis of an expansion from historical endemic areas to peripheral regions.

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

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

Real-time multiplex PCR for human echinococcosis and differential diagnosis

Molecular identification of rare human infectious pathogens appears to be one of the most relevant current methods for rapid diagnosis and management of patients. PCR techniques, in particular real-time quantitative PCR, are best suited for the detection of DNA from the pathogens, even at low concentrations. Echinococcosis infections are due to helminths of the Echinococcus genus, with closely related species involved in parasitic lesions affecting animals and, accidentally, humans. We developed a multiplex qPCR (MLX qPCR) assay allowing for the detection of four Echinococcus species involved in Europe in alveolar echinococcosis (AE) and cystic echinococcosis (CE) (Echinococcus multilocularis, E. granulosus sensu stricto, E. ortleppi, and E. canadensis), based on short mitochondrial targets. A collection of 81 fresh and formalin-fixed paraffin-embedded tissues (FFPE) of AE and CE lesions was assembled. The qPCR assays were performed in triplex for Echinococcus spp. detection, associated with a qPCR inhibitor control. A duplex qPCR was also designed to enable diagnosis of two other dead-end helminthiases (cysticercosis (Taenia solium), and toxocariasis (Toxocara cati and T. canis)). The sensitivity of the qPCR was assessed and ranged from 1 to 5 × 10^-4 ng/μL (seven PCR assays positive), corresponding to 37-42 cycles for quantifiable DNA. The specificity was 100% for all the targets. This multiplex qPCR, adapted to low amounts of DNA can be implemented in the laboratory for the rapid molecular diagnosis of Echinococcosis species.

Molecular Epidemiology of Cystic Echinococcosis in Rural Baluchistan, Pakistan: A Cross-Sectional Study

Cystic echinococcosis (CE), or hydatid cyst disease (HCD), is a zoonosis of significant importance caused by the cestode of Echinococcus granulosus sensu lato (s. l.) that affects mainly nomadic populations and has substantial economic consequences. Due to the 76% rural and nomadic population, Baluchistan is a highly endemic region in Pakistan for CE; however, it has not yet been investigated for CE. For this purpose, this study was carried out to investigate the molecular epidemiology of CE in this region. In total, 23 human hydatid cyst samples were collected from tertiary health care units in Baluchistan and processed for DNA extraction, which was then followed by sequencing of the cox1 mitochondrial gene of all 23 collected samples, genotyping, and phylogenetic and haplotype analysis. Most subjects were livestock owners (39.13%) in rural settings (73.91%). Most patients (73.19%) were pet owners (dogs) and used water from open sources for drinking. The liver was the most affected organ (52.17%), followed by the lungs (17.39%). Sequence analysis based on the cox1 gene revealed that EG genotype 1 (G1) was the most prevalent (56.52%), followed by G3 (34.78%), while some samples (8.7%) were identified as the Echinococcus canadensis (G6/7) genotype. A total of five haplotypes were detected with high haplotype diversity (0.80) and low nucleotide diversity (0.033). Phylogenetic analysis revealed two diverse sub-clades, each of G1 and G3 isolates from Baluchistan, that were evolutionarily related to previously reported G1 and G3 isolates from Pakistan and China. On the other hand, the G6/7 isolates of this study were evolutionarily identical to the already reported G6/7 isolates from Pakistan, Turkey, and Kazakhstan. This study concludes that diverse G1 and G3 EG isolates are present in this part of Pakistan, while the G6/G7 genotype was reported for the first time from Baluchistan.

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

A new species of Versteria (Cestoda: Taeniidae) parasitizing Galictis cuja (Carnivora: Mustelidae) from Patagonia, Argentina: Morphological and molecular characterization

Via morphological and molecular analysis, we describe a new species of taeniid from Patagonia (Argentina): Versteria cuja n. sp., parasitizing the Lesser grison Galictis cuja (Molina) (Carnivora: Mustelidae). This is the first report of a species of Versteria in Argentina and for a native mustelid. The new species (the third in the genus Versteria) is proposed using an integrative taxonomic approach, based on traditional morphology (distinctive morphological and morphometric diagnostic characters), genetic distances and phylogeny based on molecular data, the distinct geographical distribution, and the different definitive host species. Versteria cuja n. sp. mainly differs from Versteria mustelae (Gmelin, 1790) (from Europe) in the number of testes (54-85 vs. 83-127 in V. mustelae), the rostellum size (39-75 vs. 85-180 μm in V. mustelae), the genital atrium size (170-420 vs. 68-91 μm in V. mustelae) and in the hooks' shape. It also differs from the African species Versteria brachyacantha (Baer and Fain, 1951) by having smaller measurements regarding the main diagnostic characters, i.e. size of scolex, rostellum and suckers, number, size and shape of rostellar hooks, number of testes, and by having smooth cirrus (vs. cirrus covered with hair-like bristles in V. brachyacantha). Phylogenetical analysis using cox1 showed our specimens clustering with North American isolates of Versteria sp. in a well-supported American clade (mean genetic divergence 0.024), separated from another clade composed of different isolates of V. mustelae (0.093). The close relationship between the new species and the North American species, known as "zoonotic" Versteria sp., and responsible for fatal infections by metacestodes in free-ranging wildlife (rodents), captive primates and immunosuppressed people, lead us to think that the zoonotic potential of Versteria cuja n. sp. should not be discarded.

In Silico Evaluation of the Haplotype Diversity, Phylogenetic Variation and Population Structure of Human E. granulosus sensu stricto (G1 Genotype) Sequences

Echinococcus granulosus sensu lato is the causative agent of cystic echinococcosis (CE), which is a neglected zoonotic disease with an important role in human morbidity. In this study, we aimed to investigate the haplotype diversity, genetic variation, population structure and phylogeny of human E. granulosus sensu stricto (s.s.) (G1 genotype) isolates submitted to GenBank from different parts of the world by sequencing the mitochondrial CO1 and ND1 genes. The sequences of the mt-CO1 (401 bp; n = 133) and mt-ND1 (407 bp; n = 140) genes were used to analyze the haplotype, polymorphism and phylogenetic of 273 E. granulosus s.s. (G1 genotype) isolates. Mutations were observed at 31 different points in the mt-CO1 gene sequences and at 100 different points in the mt-ND1 gene sequences. Furthermore, 34 haplotypes of the mt-CO1 sequences and 37 haplotypes of the mt-ND1 sequences were identified. Tajima’s D, Fu’s Fs, and Fu’s LD values showed high negative values in both mt-CO1 and mt-ND1 gene fragments. The haplotype diversities in the sequences retrieved from GenBank in this study indicate that the genetic variation in human isolates of E. granulosus s.s. in western countries is higher than in eastern countries. This may be due to demographic expansions due to animal trades and natural selections.

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.

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

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

Evaluation of <em>Echinococcus</em> DNA by polymerase chain reaction (PCR) in cystic <em>Echinococcosis</em> of the liver

OBJECTIVES

The aim of this study was to determine the DNA and genotypes of Echinococcus granulosus in liver cyst hydatids isolated in humans.

MATERIAL AND METHODS

This study was conducted prospectively at the Department of General Surgery of the Cerrahpaşa School of Medicine, University of İstanbul-Cerrahpaşa, between January 2015 and June 2016 in 30 patients who were operated on for cystic Echinococcosis. E. granulosus DNA was analyzed using the Polymerase Chain Reaction (PCR) method in the cyst samples (protoscolex and/or germinative membrane) obtained during the operation, and genotype was determined in the PCR positive samples by sequence analysis. At the same time, indirect hemagglutination (IHA) was used to test for the presence of antibodies in the patients' blood.

RESULTS

E. granulosus DNA was found in 29 out of 30 cystic Echinococcosis of the liver samples. All of the 29 cystic Echinococcosis samples were found to be G1 (sheep) species. Also, IHA was positive in 22 patients and negative in eight patients.

CONCLUSION

In the present study, G1 species was the most commonly seen liver cystic Echinococcosis species. We suggest that a vaccine, which could be developed against prevalent regional genotypes, would be efficacious in the prevention of the disease with a cause of mortality and morbidity.

Genetic Diversity and Haplotype Analysis of Cattle Hydatid Cyst Isolates Using Mitochondrial Markers in Turkey

Echinococcus granulosus sensu lato (s.l.) causes cystic echinococcosis in ungulates and humans. The current study was designed to find the genetic diversity and haplotypic profiles of hydatid cysts from the lungs of cattle in three provinces in eastern Turkey. Individual cyst isolates (n = 60) were collected from infected cattle lungs after slaughter and then samples were stored in ethanol (70%) until further use. From each isolate, total gDNA was extracted from the cysts’ germinal layers. A partial (875 bp) mt-CO1 gene was amplified by PCR and sequenced unidirectionally. The final size of the trimmed sequences was 530 bp for 60 sequences. Sequence and haplotype analyses were performed, followed by phylogenetic analyses. According to BLAST searches, all sequences were detected as E. granulosus s.s. (G1 and G3 strains). Forty-nine point mutations were identified. In addition, five conserved fragments were detected in all sequences. The haplotype analysis diagram showed E. granulosus s.s. haplotypes organized in a star-like configuration. The haplotypes were characterized by 1–17 mutations compared with the fundamental focal haplotype. Thirty-three haplotypes were determined in 60 samples of which 17 (28.3%) belonged to the main haplotype (Hap_06). The mt-CO1 sequences revealed 49 polymorphic sites, 34.5% (20/49) of which were informative according to parsimony analysis.

Molecular Study Of Hydatid Disease In Iraqi Goats By using The Mitochondrial Cytochrome C Oxidase Subunit 1 Gene

The aim of the present study was to identify and recognize the genotype for cystic Echinococcosis that infects goats (n=19) in Iraq. The hydatid cyst was collected from different parts of the body, i.e. lungs, liver, heart, spleen and peritoneal cavity. The current study was conducted in five different regions of Iraq (Anbar, Baghdad, Saladdin, Karkuk, Babylon during October 2018 to July 2019. The mitochondria DNA was extracted and screened for the presence of (CO1) cytochrome C oxidase subunit 1 gene using polymer chain reactions (PCR). Amplification size was around 450bp. The amplicon was isolated and purified. The isolated CO1 amplicon was sequenced. The CO1 putative sequence was BLAST with available sequence from NCBI. The genetic tree was deduced. The genotype G1 is the most frequently spread strains and considered as a key source for infection in goats of Iraq.

Assessment of the Vaccination Program against Cystic Echinococcosis in Sheep in the Pehuenche Community of Central Chile

Echinococcosis is a neglected zoonosis that uses dogs and sheep as its main hosts in Chile. The Eg95 vaccine against sheep infection has been included in some control programs. Here, we assess the efficacy of the vaccination program in the hyperendemic Alto Biobío commune after 3 years of execution. Fisher’s test and generalized linear models were used in the assessment. The program tried to offer a first dose at 2 months of age, a booster 1 month later, and yearly vaccination. Given logistic difficulties, important delays in vaccination occurred, and most animals did not receive the first booster. Dog deworming was not included in the program. Likely due to the aforementioned factors, the overall frequency of infection was not lower, but the proportion of large (>5 mm) cysts and fertile cysts was smaller after the program. The frequency of infection and/or the number of cysts were lower when the age at first dose was younger and the first booster was administered 1 month after the first dose. The results suggest that vaccination affects both cyst development after the larvae reach the target organs, as well as the development of the protoscolex once the cysts start developing.

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

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

Comparative Characterization of Mitogenomes From Five Orders of Cestodes (Eucestoda: Tapeworms)

The recognized potential of using mitogenomics in phylogenetics and the more accessible use of high-throughput sequencing (HTS) offer an opportunity to investigate groups of neglected organisms. Here, we leveraged HTS to execute the most comprehensive documentation of mitogenomes for cestodes based on the number of terminals sequenced. We adopted modern approaches to obtain the complete mitogenome sequences of 86 specimens representing five orders of cestodes (three reported for the first time: Phyllobothriidea, “Tetraphyllidea” and Trypanorhyncha). These complete mitogenomes represent an increase of 41% of the mitogenomes available for cestodes (61–147) and an addition of 33% in the representativeness of the cestode orders. The complete mitochondrial genomes are conserved, circular, encoded in the same strand, and transcribed in the same direction, following the pattern observed previously for tapeworms. Their length varies from 13,369 to 13,795 bp, containing 36 genes in total. Except for the Trypanorhyncha specimen, the gene order of the other four cestode orders sequenced here suggests that it could be a synapomorphy for the acetabulate group (with a reversion for taenids). Our results also suggest that no single gene can tell all the evolutionary history contained in the mitogenome. Therefore, cestodes phylogenies based on a single mitochondrial marker may fail to capture their evolutionary history. We predict that such phylogenies would be improved if conducted under a total evidence framework. The characterization of the new mitochondrial genomes is the first step to provide a valuable resource for future studies on the evolutionary relationships of these groups of parasites.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Genotypes of Echinococcus Species from Cattle in Tanzania

Cystic echinococcosis is a zoonotic parasitic disease caused by Echinococcus species. Tanzania is one of the endemic countries with cystic echinococcosis. This study focussed on identifying genotypes of Echinococcus spp. in Tanzania. We collected 7 cysts from cattle in Mwanza municipal (n=4) and Loliondo district (n=3). The cysts from Mwanza were all E. ortleppi and fertile. In contrast, the cysts from Loliondo were all E. granulosus sensu stricto and sterile. Two from the 4 cysts were a new haplotype of E. ortleppi (G5). These results can improve the preventive and control programs for humans and livestock in Tanzania. To our knowledge, this study is considered the first to identify the genotype and haplotype of Echinococcus spp. in Tanzania.

Advances in the treatment, diagnosis, control and scientific understanding of taeniid cestode parasite infections over the past 50 years

In the past 50 years, enormous progress has been made in the diagnosis, treatment and control of taeniid cestode infections/diseases and in the scientific understanding thereof. Most interest in this group of parasites stems from the serious diseases that they cause in humans. It is through this lens that we summarize here the most important breakthroughs that have made a difference to the treatment of human diseases caused by these parasites, reduction in transmission of the taeniid species associated with human disease, or understanding of the parasites' biology likely to impact diagnosis or treatment in the foreseeable future. Key topics discussed are the introduction of anti-cestode drugs, including benzimidazoles and praziquantel, and the development of new imaging modalities that have transformed the diagnosis and post-treatment monitoring of human echinococcoses and neurocysticercosis. The availability of new anti-cestode drugs for use in dogs and a detailed understanding of the transmission dynamics of Echinococcus granulosus sensu lato have underpinned successful programs that have eliminated cystic echinococcosis in some areas of the world and greatly reduced the incidence of infection in others. Despite these successes, cystic and alveolar echinococcosis and neurocysticercosis continue to be prevalent in many parts of the world, requiring new or renewed efforts to prevent the associated taeniid infections. Major advances made in the development of practical vaccines against E. granulosus and Taenia solium will hopefully assist in this endeavour, as might the understanding of the parasites' biology that have come from an elucidation of the nuclear genomes of each of the most important taeniid species causing human diseases.

Epidemiological, Morphometric, and Molecular Investigation of Cystic Echinococcosis in Camel and Cattle From Upper Egypt: Current Status and Zoonotic Implications

Cystic echinococcosis has been considered one of the major parasitic zoonoses which is associated with severe economic losses. The present study was undertaken to investigate the occurrence, organ distribution, cyst fertility, and viability of cystic echinococcosis in slaughtered camels and cattle from various abattoirs in Assiut Governorate, Egypt. The work also involved morphological, morphometric, and molecular identification of the parasite. The occurrence of hydatid cysts was investigated in total number of 100 lungs of camels and 574 liver and lungs of cattle admitted to three slaughterhouses at Assiut Governorate, Egypt. Moreover, several individual variable factors, including organ involvement, age, sex, and hydatid cyst characteristics, were studied to identify their possible association with the occurrence of the disease. Genomic DNA was extracted from the hydatid cysts, followed by molecular identification of the parasite through amplification of ribosomal DNA internal transcribed spacer (ITS) regions. Hydatid cysts were found in 6 camels (6%) out of 100 inspected camels, while 5 hydatid cysts (0.87%) were detected in a total number of 574 cattle examined. The parasite was detected exclusively in lungs of camels, while lungs were the main organ infected by the parasite in cattle and one hydatid cyst was found in the liver (0.17%). In camel, 66.7, 16.65, and 16.65%of detected cysts were fertile, sterile, and calcified, respectively, while in cattle, these percentages were 60, 20, and 20%, respectively. None of the studied variable factors were significantly associated with the occurrence of the disease in camels, with the exception that all cysts were found in the lung. Conversely, we found a significant association (P < 0.05) between the age and sex of the slaughtered cattle and the occurrence of hydatid cysts. In this respect, the rate of infection was higher in female cattle and those cattle more than 5 years (P < 0.05). The morphological, morphometric, and molecular studies confirmed the presence of the parasite. Taken together, our results concluded that camels and cattle play a potential role in maintaining the transmission cycle of this zoonotic parasite.

Cestodes in the genomic era

The first cestode genomes were obtained by an international consortium led by the Wellcome Sanger Institute that included representative institutions from countries where the sequenced parasites have been studied for decades, in part because they are etiological agents of endemic diseases (Argentina, Uruguay, Mexico, Canada, UK, Germany, Switzerland, Ireland, USA, Japan, and China). After this, several complete genomes were obtained reaching 16 species to date. Cestode genomes have smaller relative size compared to other animals including free-living flatworms. Moreover, the features genome size and repeat content seem to differ in the two analyzed orders. Cyclophyllidean species have smaller genomes and with fewer repetitive content than Diphyllobothriidean species. On average, cestode genomes have 13,753 genes with 6 exons per gene and 41% GC content. More than 5,000 shared cestode proteins were accurately annotated by the integration of gene predictions and transcriptome evidence being more than 40% of these proteins of unknown function. Several gene losses and reduction of gene families were found and could be related to the extreme parasitic lifestyle of these species. The application of cutting-edge sequencing technology allowed the characterization of the terminal sequences of chromosomes that possess unique characteristics. Here, we review the current status of knowledge of complete cestode genomes and place it within a comparative genomics perspective. Multidisciplinary work together with the implementation of new technologies will provide valuable information that can certainly improve our chances to finally eradicate or at least control diseases caused by cestodes.

Red foxes harbor two genetically distinct, spatially separated Echinococcus multilocularis clusters in Brandenburg, Germany

Background

Alveolar echinococcosis (AE) is a clinically serious zoonosis caused by the fox tapeworm Echinococcus multilocularis. We studied the diversity and the distribution of genotypes of E. multilocularis isolated from foxes in Brandenburg, Germany, and in comparison to a hunting ground in North Rhine-Westphalia.

Methods

Echinococcus multilocularis specimens from 101 foxes, 91 derived from Brandenburg and 10 derived from North Rhine-Westphalia, were examined. To detect potential mixed infections with different genotypes of E. multilocularis, five worms per fox were analyzed. For genotyping, three mitochondrial markers, namely cytochrome c oxidase subunit 1 (Cox1), NADH dehydrogenase subunit 1 (Nad1), and ATP synthase subunit 6 (ATP6), and the nuclear microsatellite marker EmsB were used. To identify nucleotide polymorphisms, the mitochondrial markers were sequenced and the data were compared, including with published sequences from other regions. EmsB fragment length profiles were determined and confirmed by Kohonen network analysis and grouping of Sammon’s nonlinear mapping with k-means clustering. The spatial distribution of genotypes was analyzed by SaTScan for the EmsB profiles found in Brandenburg.

Results

With both the mitochondrial makers and the EmsB microsatellite fragment length profile analyses, mixed infections with different E. multilocularis genotypes were detected in foxes from Brandenburg and North Rhine-Westphalia. Genotyping using the mitochondrial markers showed that the examined parasite specimens belong to the European haplotype of E. multilocularis, but a detailed spatial analysis was not possible due to the limited heterogeneity of these markers in the parasite population. Four (D, E, G, and H) out of the five EmsB profiles described in Europe so far were detected in the samples from Brandenburg and North Rhine-Westphalia. The EmsB profile G was the most common. A spatial cluster of the E. multilocularis genotype with the EmsB profile G was found in northeastern Brandenburg, and a cluster of profile D was found in southern parts of this state.

Conclusions

Genotyping of E. multilocularis showed that individual foxes may harbor different genotypes of the parasite. EmsB profiles allowed the identification of spatial clusters, which may help in understanding the distribution and spread of the infection in wildlife, and in relatively small endemic areas.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-05038-0.

Another Piece of the Puzzle: Echinococcus oligarthrus Recorded in Jaguarundis (Herpailurus yagouaroundi) in Southern Brazil

Echinococcus oligarthrus is a tapeworm endemic to South America and widely distributed in the Amazon region. Its lifecycle is maintained by relationships between felids and their prey, mainly small sylvatic rodents, but humans can be infected occasionally. We report two female jaguarundis (Herpailurus yagouaroundi) harboring E. oligarthrus in southern Brazil. The felines were found road killed in periurban areas, and, during necropsy, the small intestine was examined. Visual inspection revealed helminths, which were submitted to microscopy and molecular examination. Morphologically, they were around 2.5 mm long, with four suckers and an armed scolex with two rows of hooks. Phylogenetic reconstruction using cytochrome c oxidase subunit I gene sequences placed samples from south Brazil in the same clade as all other E. oligarthrus samples, but as a sister group. Genetic distance gave similar results, resulting in a divergence of 0.087% between the samples described in this study and other samples. The geographic pattern of genetic diversity, as assessed by analysis of molecular variance, suggests that the divergency results from isolation by distance. This finding expands the geographic range of E. oligarthrus and brings new insights to help understand and prevent the zoonosis it causes.

Determination of Echinococcus granulosus Antigen B Polymorphism in Human and Animal Isolates From Alborz Province by PCR-SSCP

Background: Echinococcus granulosus is one of the most important pathogens in medicine. This parasite is able to cause a hydatid cyst in humans, which causes various human and financial losses annually. Objective: This study focused on determining the polymorphism of antigen B (AgB) of E. granulosus in the human and animal samples of Alborz province. Materials and Methods: In this study, 50 samples of the hydatid cyst fluid (HCF), 10 human samples, and 40 sheep samples were collected, then the DNA was extracted from the samples. During the polymerase chain reaction (PCR) process, the corresponding fragment was replicated in the AgB gene. Subsequently, PCR-single-strand conformation polymorphism (SSCP) was performed to investigate genetic diversity. Results: All 50 isolates used in this study showed the AgB in 350 bp after conducting PCR. In addition, all isolates demonstrated similar band patterns after the PCR-SSCP assay. Conclusion: In 50 isolates, one banding pattern was observed after PCR-SSCP, while no polymorphism was detected in any of the isolates.

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

Background

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

Methods

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

Results

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

Conclusion

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

Graphical Abstract

The First Record of Echinococcus ortleppi (G5) Tapeworms in Grey Wolf (Canis lupus)

The aim of this study is to confirm the presence and molecular identification of Echinococcus tapeworms in wolves from south-eastern Poland. An investigation was carried out on the intestines of 13 wolves from south-eastern Poland. The small intestines were divided into three equal segments. Each segment was separately examined using the sedimentation and counting technique (SCT). The detected Echinococcus tapeworms were isolated and identified by PCRs and sequencing (nad1 and cox1 genes). Additionally, DNA isolated from the feces of wolves positive for Echinococcus tapeworms was examined with two diagnostic PCRs. The intestines of one wolf were positive for E. granulosus s.l. when assessed by SCT; the intestine was from a six-year-old male wolf killed in a communication accident. We detected 61 adult tapeworms: 42 in the anterior, 14 in the middle, and 5 in the posterior parts of the small intestine. The PCRs conducted for cox1 and nad1 produced specific products. A sequence comparison with the GenBank database showed similarity to the deposited E. ortleppi (G5) sequences. An analysis of the available phylogenetic sequences showed very little variation within the species of E. ortleppi (G5), and identity ranged from 99.10% to 100.00% in the case of cox1 and from 99.04% to 100.00% in the case of nad1. One of the two diagnostic PCRs used and performed on the feces of Echinococcus-positive animals showed product specific for E. granulosus. This study showed the presence of adult E. ortleppi tapeworms in wolves for the first time.

Epidemiological and Molecular Characterization of Echinococcus granulosus Isolated from Small Ruminants in Kashmir Valley, India

BACKGROUND

Cystic Echinococcosis (CE) is an emergent or re-emergent zoonosis and remains a public health and economic problem all over the world.

METHODS

The present study was carried on the prevalence and genotypes of Echinococcus present in small ruminants in Kashmir valley. A total of 2100, sheep (2052) and goats (48), slaughtered or spontaneously dead, from various areas of Kashmir valley were screened for the presence of hydatidosis. In case of goat none of the cases were found positive for hydatidosis, whereas, all the positive cases (85) were recorded in sheep only. The overall prevalence of hydatidosis was 4.04%. The prevalence was higher in female sheep (5.46%) compared to males (2.83%). Season-wise highest prevalence was in summer (4.55%), followed by autumn (4.1%), spring (3.89%) and winter (2.5%).The liver was observed to be the most frequently infected organ with relative prevalence of 61.17% followed by lungs (38.82%).The rDNA-ITS1 fragment of positive samples was amplified with BD1 / 4S primers.

RESULTS

The length of amplified fragment for all isolated samples was 1000bps. The products obtained on PCR were digested with four restriction enzymes (Rsa 1, Alu 1, Msp 1 and Taq1). Rsa 1, Alu 1, Msp 1 yielded identical fragments, 300 and 700 bp in sheep. TaqI restriction enzyme had no effect on PCR product and after digestion; intact 1000bps fragment was seen.

CONCLUSION

Phylogenetic analysis of ITS1 gene revealed that the common sheep strain (G1) is the predominant genotype in sheep in Kashmir valley.

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

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

Exploring Risk for Echinococcosis Spillover in Northern Minnesota Tribal Communities

Echinococcus spp. are zoonotic cestode parasites with a worldwide distribution and a complex, two-host life cycle involving carnivore definitive hosts and small mammal or ungulate intermediate hosts. Surveillance for Echinococcus spp. in the Midwestern United States (USA) is rare. Using a mixed-methods approach, we examined Echinococcus infection risks in wildlife and domestic dogs in four Minnesota Tribal Nations. We hypothesized that the spillover of Echinococcus spp. into domestic dogs would vary with the presence or absence of suspected wildlife host species and certain behaviors associated with domestic dog ownership, like feeding wildlife host carcasses or frequency of veterinary care. Among 83 dogs tested, three (3.6%) were positive for Echinococcus spp. Despite low prevalence, pet owner survey and focus group findings indicated that dogs encounter peri-domestic wildlife most often when they roam freely or consume wildlife carcasses. This study demonstrates a need for further research into spillover potential of endemic zoonotic Echinococcus spp. in the Midwest USA.

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.

Human and animal cystic echinococcosis in Tataouine governorate: hypoendemic area in a hyperendemic country, myth or reality?

BACKGROUND

Cystic echinococcosis (CE) has a worldwide distribution and is especially prevalent in North African countries. With a mean annual surgical incidence (ASI) of CE of 12.7 per 100,000 inhabitants, Tunisia is one of the most CE endemic countries in the Mediterranean area. Tataouine governorate is considered to be the most CE hypoendemic region in Tunisia (ASI = 0.92) despite favourable socioeconomic conditions that enable maintenance of the Echinococcus granulosus sensu lato (s.l.) life-cycle and a significant environmental contamination with E. granulosus s.l. eggs. The aim of this study was to assess human CE seroprevalence, prevalence of CE in food animals and environmental contamination by E. granulosus s.l. eggs in different districts of Tataouine governorate.

METHODS

This study was conducted from January to December 2018. A total of 374 human sera samples were tested for the presence of immunoglobulin G antibodies against E. granulosus using a commercial ELISA kit. Specimens were also collected from animals slaughtered at the Tataouine abattoir (n = 8609) and examined for the presence of hydatid cysts; 111 hydatid cysts were genotyped. Eggs of E. granulosus s.l. were identified by PCR and DNA sequencing from dog faecal samples (n = 288).

RESULTS

Serological tests showed that 8.5% of the sera samples tested were positive for E. granulosus-specific antibodies. The average prevalence of hydatidosis in livestock was 1.6%, and CE infection was more prevalent in cattle than in sheep, goats and dromedaries. The contamination rate of dog faeces by E. granulosus sensu stricto eggs varied significantly from 0 to 23.5% depending on the collection area. Molecular analyses only revealed the presence of the G1 genotype for cysts and eggs.

CONCLUSIONS

Based on our findings, CE is likely to be more endemic in the Tataouine governorate than previously described. Thus, to implement an effective control programme against CE, a national survey should be carried out to determine human CE prevalence in the different Tunisian governorates.

Echinococcus multilocularis genetic diversity in Swiss domestic pigs assessed by EmsB microsatellite analyzes

Assessing the genetic diversity of the parasite Echinococcus multilocularis provides key information about the temporal and spatial strain flow in a given area. Previous studies indicated that a historical endemic area conventionally presents a relatively high genetic diversity, whereas peripheral or newly endemic areas exhibit a more restricted variability of the parasite. The Swiss plateau region is part of the European historically endemic area, and the genetic diversity has already been investigated by assessing either human metacestode isolates or adult worms from foxes. To date, there have been no studies covering the whole geographical area affected by the parasite. The aim of the present study was to make use of the domestic pig to investigate the genetic diversity of E. multilocularis in relation to spatial distribution. A total of 55 E. multilocularis-induced hepatic lesions from slaughtered pigs from Switzerland were studied using EmsB microsatellite analyzes, and findings were compared to already published data (originating from human, primate, foxes, and rodent samples). A total of 12 EmsB profiles were described among the domestic pigs, some of them presenting a clear spatial organization in the Swiss plateau, with three of the main profiles geographically separated. One of the 12 EmsB profiles has been newly identified for Switzerland in this study, while the other 11 profiles had been previously described in other Swiss E. multilocularis isolates from other hosts. Overall, a total of 18 EmsB profiles have so far been described within the Swiss endemic area. Six profiles appeared only among human, primate, rodent, and fox samples. Based on a richness and diversity accumulation analysis, the sampling efficiency for the whole studied area has now been improved considerably by compilation of 178 E. multilocularis specimens obtained from four different intermediate and one definitive host species in Switzerland.

Perspectives on intestinal tapeworm infections: An evaluation of direct and indirect life-cycles with a special emphasis on species of Hymenolepis

Numerous experimental studies have been conducted on the rodent tapeworm, Hymenolepis microstoma. In contrast, less is known about the life-cycle and immunobiology of the zoonotic dwarf tapeworm, Hymenolepis nana. However, H. nana appears to be unique in that; (i) it can complete its entire life-cycle within a single mammalian host, and (ii) cysticercoids that develop in beetle intermediate hosts are tailed, while those that develop in the intestinal tissue of mammals are tailless. This is in contrast to all other Hymenolepis spp., which only appear to develop tailed cysticercoids in beetles or experimentally infected immunodeficient rodents. Even though H. microstoma and H. nana are phylogenetically much closer to each other than to Hymenolepis diminuta, when mice with severe combined immunodeficiency (SCID) were inoculated with H. microstoma eggs, hatched oncospheres invaded the intestinal tissue and developed into infective tailed cysticercoids in approximately 11 days. Therefore, H. nana appears to be truly unique in its ability to develop tailed cysticercoids in beetles and tailless cysticercoids in mammals. These unique evolutionary characteristics are discussed in relation to other cyclophyllidean cestodes, including Taenia solium and Echinococcus spp.