First phenotypic description of Fasciola hepatica/Fasciola gigantica intermediate forms from the human endemic area of the Nile Delta, Egypt

First morphometric and molecular characterization of Fasciola spp. in Northwest Tunisia

The aim of this study was to characterize the Tunisian Fasciola spp. flukes by morphometric and molecular analyses. Flukes were collected from livers of sheep slaughtered in Sejnane slaughterhouses (Bizerte gouvernorate, Northwest Tunisia) between January and March 2021.Five morphometric parameters were determined for all the liver flukes, as follows: (i) total body length (BL), (ii) distance between ventral sucker and the tail (VS-T), (iii) distance between oral sucker and ventral sucker (OS-VS), (iv) abdomen diameter (AD), (v) tail diameter (TD) and the body length to width ratio (BL/BW). Molecular identification of the fluke specimens was carried out by polymerase chain reaction, restriction fragment polymorphism (PCR-RFLP) of a 680 bp sequence of the internal transcribes spacer 1 (ITS1) gene and by amplification, sequencing, and phylogenetic analysis of a 500 bp sequence of the ITS2 gene. Morphometric measurements showed that the mean of the total body length of the adult flukes was 21.1 ± 2.7 mm with minimum and maximum lengths of 13 and 31 mm, respectively. The PCR-RFLP analysis revealed a single profile consisting of three bands of approximately 370, 100, and 60 bp. Fasciola sequences described in the present study (GenBank numbers: OQ457027 and OQ457028) showed 99.58-100% identity to Fasciola hepatica. In conclusion, the results of this study show that molecular and phylogenetic analyses confirm the presence of a single species of F. hepatica in the Sejnane region Northwest of Tunisia. However, further studies are needed to identify the occurrence of Fasciola species in other Tunisian regions.

The regulatory roles of Fasciola hepatica GSTO1 protein in inflammatory cytokine expression and apoptosis in murine macrophages

Fascioliasis, a global zoonotic parasitic disease, is mainly caused by Fasciola hepatica (F. hepatica) parasitizing in the livers of hosts, mainly humans and herbivores. Glutathione S-transferase (GST) is one of the important excretory- secretory products (ESPs) from F. hepatica, however, the regulatory roles of its Omega subtype in the immunomodulatory effects remain unknown. Here, we expressed F. hepatica recombinant GSTO1 protein (rGSTO1) in Pichia pastoris and analyzed its antioxidant properties. Then, the interaction between F. hepatica rGSTO1 and RAW264.7 macrophages and its effects on inflammatory responses and cell apoptosis were further explored. The results revealed that GSTO1 of F. hepatica owned the potent ability to resist oxidative stress. F. hepatica rGSTO1 could interact with RAW264.7 macrophages and inhibit its cell viability, furthermore, it may suppress the production of pro-inflammatory cytokines IL-1β, IL-6 and TNF-α, but promote the expression of anti-inflammatory cytokine IL-10. In addition, F. hepatica rGSTO1 may down-regulate the ratio of Bcl-2/Bax, and increase the expression of pro-apoptotic protein caspase-3, thereby eliciting the apoptosis of macrophages. Notably, F. hepatica rGSTO1 inhibited the activation of nuclear factor-κB (NF-κB) and mitogen‑activated protein kinases (MAPKs p38, ERK and JNK) pathways in LPS-activated RAW264.7 cells, exerting potent modulatory effects on macrophages. These findings suggested that F. hepatica GSTO1 can modulate the host immune response, which provided new insights into the immune evasion mechanism of F. hepatica infection in host.

Molecular characterization of Fasciola hepatica in endemic regions of Colombia

Fasciola hepatica is a zoonotic trematode that affects a wide range of hosts, including cattle, sheep, and goats. The economic impact of the parasite on the cattle industry is significant, with high losses reported worldwide. While its impact on human health was previously underestimated, recent years have seen a rise in fascioliasis cases, leading to increased interest among researchers globally. To characterize the genetic diversity and intraspecific variation of this parasite in South America, specifically in Colombia, we collected 105 adult parasites from cattle bile ducts in seven Colombian departments (Antioquia, Boyacá, Santander, Cauca, Cundinamarca, Nariño, Norte de Santander, and Santander) to assess the parasite's phenotypic analyses, genetic diversity, and population structure. A computer image analysis system (CIAS) was applied based on standardized morphological measurements. Liver-fluke size was studied by principal component analysis (PCA). DNA sequences were obtained for nuclear markers such as the 28S, β-tubulin 3, ITS1, ITS2, and the mitochondrial marker Cytochrome Oxidase I (COI). Multiple statistical tests were performed, and the parasite's population structure was analyzed. Maximum Likelihood (ML) phylogenetic reconstructions were carried out using the sequences obtained herein and sequences available in GenBank. Morphological results revealed that all the obtained individuals matched F. hepatica's morphology. There was no evidence of high genetic diversity, and the absence of genetic structure at the country-level was notable, possibly caused by a demographic expansion of this trematode in Colombia or the low resolution of the molecular markers employed. Future studies are still needed to unveil the genetic population structure of F. hepatica across the country.

Artemisia vulgaris anthelmintic activities to ova and adult stages of Fasciola gigantica in vitro

Background and Aim

Fasciolosis due to Fasciola gigantica is endemic to tropical countries and Fasciola hepatica in temperate climates, highly detrimental to livestock and known as foodborne zoonotic diseases. The strategic control of the disease is mainly the use of chemical anthelmintic. This study aimed to evaluate the anthelmintic properties of Artemisia vulgaris extract on the ova and adult stages of F. gigantica.

Materials and Methods

Samples were collected from the Ampel Abbatoir, Boyolali District, Central Java, Indonesia. The ova from 20-gallbladders of cattle which were naturally infected with F. gigantica and 270 living F. gigantica worms were used in this study. The ovicidal assay was performed by incubating the ova with A. vulgaris in different concentrations, that is, 5%, 2.5%, and 1.25% for 5, 9, 11, 14, and 16 days. The efficacies were evaluated by quantification of ova degeneration during developmental stages in different time points and egg-hatch assay. The flukicidal effects were observed by mortality assay in 5, 10, 20, 40, 80, 160, 320, and 640 min incubations followed by scanning electron microscopy for surface morphology and histology of the fluke's transversal sections.

Results

The concentration of 5% A. vulgaris showed the strongest ovicidal activities. The percentage of hatching ova on day 16 at concentrations of 5%, 2.5%, and 1.25% were 3.33%, 6.67%, and 16.67%. These ova hatch assay showed a significant reduction (p < 0.001) compared to untreated control. The flukicidal effect was significant (p < 0.001) at a concentration of 20%, with a mortality rate reaching 66.67% in the 40 min of incubation time. The surface properties of the adult worms, including the spine, tegument, acetabulum, intestine, and vitelline follicles, were disintegrated.

Conclusion

The results showed that A. vulgaris has the potential ovicidal and flukicidal properties to F. gigantica. The active compounds remained necessary to be elucidated further and its modes of action would be interesting to be predicted by molecular docking modeling.

Geographical Influence on Morphometric Variability of Genetically “Pure” Schistosoma haematobium Eggs from Sub-Saharan Migrants in Spain

Schistosome eggs play a key role in schistosomiasis diagnosis and research. The aim of this work is to morphogenetically study the eggs of Schistosoma haematobium found in sub-Saharan migrants present in Spain, analyzing their morphometric variation in relation to the geographical origin of the parasite (Mali, Mauritania and Senegal). Only eggs considered “pure” S. haematobium by genetic characterization (rDNA ITS-2 and mtDNA cox1) have been used. A total of 162 eggs obtained from 20 migrants from Mali, Mauritania and Senegal were included in the study. Analyses were made by the Computer Image Analysis System (CIAS). Following a previously standardized methodology, seventeen measurements were carried out on each egg. The morphometric analysis of the three morphotypes detected (round, elongated and spindle) and the biometric variations in relation to the country of origin of the parasite on the egg phenotype were carried out by canonical variate analysis. Mahalanobis distances, when all egg measurements were analyzed, showed differences between: (i) Mali-Mauritania, Mali-Senegal and Mauritania-Senegal in the round morphotype; (ii) Mali-Mauritania and Mauritania-Senegal in the elongated morphotype; and (iii) Mauritania-Senegal in the spindle morphotype. Mahalanobis distances, when spine variables were analyzed, showed differences between Mali-Senegal in the round morphotype. In conclusion, this is the first phenotypic study performed on individually genotyped “pure” S. haematobium eggs, allowing the assessment of the intraspecific morphological variations associated with the geographical origin of the schistosome eggs.

New perspectives for fascioliasis in Upper Egypt's new endemic region: Sociodemographic characteristics and phylogenetic analysis of Fasciola in humans, animals, and lymnaeid vectors

BACKGROUND

Fascioliasis is a significant vector-borne disease that has emerged in numerous tropical and subtropical countries causing severe health problems. Egypt is one of the fascioliasis endemic regions; however, the current situation in Upper Egypt is understudied, with only sporadic human cases or outbreaks. This study aims to highlight the sociodemographic characteristics of human fascioliasis in a newly emerged endemic area in Upper Egypt, along with risk factors analysis and the molecular characteristics of the fasciolid population in humans, animals, and lymnaeid snails.

METHODOLOGY/PRINCIPAL FINDINGS

The study reported Fasciola infection in patients and their close relatives by analyzing the risk of human infection. Morphological and molecular characterization was performed on lymnaeid snails. Multigene sequencing was also used to characterize fasciolids from human cases, cattle, and pooled snail samples. The study identified asymptomatic Fasciola infection among family members and identified the presence of peridomestic animals as a significant risk factor for infection. This is the first genetic evidence that Radix auricularia exists as the snail intermediate host in Egypt.

CONCLUSIONS/SIGNIFICANCE

This study revealed that Assiut Governorate in Upper Egypt is a high-risk area for human fascioliasis that requires additional control measures. Fasciola hepatica was the main causative agent infecting humans and snail vectors in this newly emerged endemic area. In addition, this is the first report of R. auricularia as the snail intermediate host transmitting fascioliasis in Upper Egypt. Further research is required to clarify the widespread distribution of Fasciola in Egypt's various animal hosts. This provides insight into the mode of transmission, epidemiological criteria, and genetic diversity of fasciolid populations in Upper Egypt.\.

Human and Animal Fascioliasis: Origins and Worldwide Evolving Scenario

Fascioliasis is a plant- and waterborne zoonotic parasitic disease caused by two trematode species: (i) Fasciola hepatica in Europe, Asia, Africa, the Americas, and Oceania and (ii) F. gigantica, which is restricted to Africa and Asia. Fasciolid liver flukes infect mainly herbivores as ruminants, equids, and camelids but also omnivore mammals as humans and swine and are transmitted by freshwater Lymnaeidae snail vectors. Two phases may be distinguished in fasciolid evolution. The long predomestication period includes the F. gigantica origin in east-southern Africa around the mid-Miocene, the F. hepatica origin in the Near-Middle East of Asia around the latest Miocene to Early Pliocene, and their subsequent local spread. The short postdomestication period includes the worldwide spread by human-guided movements of animals in the last 12,000 years and the more recent transoceanic anthropogenic introductions of F. hepatica into the Americas and Oceania and of F. gigantica into several large islands of the Pacific with ships transporting livestock in the last 500 years. The routes and chronology of the spreading waves followed by both fasciolids into the five continents are redefined on the basis of recently generated knowledge of human-guided movements of domesticated hosts. No local, zonal, or regional situation showing disagreement with historical records was found, although in a few world zones the available knowledge is still insufficient. The anthropogenically accelerated evolution of fasciolids allows us to call them "peridomestic endoparasites." The multidisciplinary implications for crucial aspects of the disease should therefore lead the present baseline update to be taken into account in future research studies.

Economic losses, morpho-molecular identification, and identity of Fasciola species recovered from Egypt

A retrospective study to estimate economic losses caused by livers condemnation, due to fascioliasis, of slaughtered cattle and buffaloes in Egypt during the period of 2016-2020, was done. Moreover, a morpho-molecular identification of collected liver flukes from slaughtered animals in municipal abattoirs was conducted. Livers of naturally infected carcasses were obtained from slaughtered animals in Beni-Suef, Cairo and Tanta provinces, Egypt during 2019-2020 for phenotypic characterization of recovered Fasciola species and molecular identification of collected worms using PCR targeting the ITS-1 region. Findings of the retrospective study revealed that percentages of livers condemnation of cattle and buffaloes ranged from 0.79 to 0.66% during the period from 2016 to 2020. The highest percentages were detected in the south Egypt (2.5-6.0%) with the highest economic losses (261850-616300 USD annually). Morphometrically, collected flukes categorized into Fasciola hepatica and Fasciola gigantica. No intermediate forms (Fasciola sp.-like) were detected. Sequencing analysis of ITS-1 PCR products showed that only Fasciola hepatica (26/34) and F. gigantica (8/34) isolates were found, with no intermediate forms, Fasciola sp.-like, could be identified. Currently, Fasciola hepatica was 100% identical with the Egyptian species (LC076196 and JF294998), French species (JF294999), and Iranian species (MF969009 and MK377150). Moreover, the obtained F. gigantica species showed 100% identity with Egyptian ones (LC076125, LC076108 and KX198619), Iranian (KF982047 and MF372919), and other GenBank specimens from Vietnam, Cameroon and India. In conclusion, South Egypt showed the highest economic losses due to fascioliasis, especially Aswan province. Fasciola hepatica was more common than F. gigantica, while the hybrid form was not detected.

Comparison of Three Diagnostic Methods to Detect the Occurrence of Fasciola Species in Communally Grazed Cattle in the North West Province, South Africa

Fasciolosis causes significant economic losses in commercial cattle herds in South Africa, but its prevalence is unknown in most communal areas. A cross-sectional study was conducted with the aim of determining the occurrence of bovine fasciolosis using three different diagnostic methods in Moretele Local Municipality in Bojanala District, North West Province. Faecal samples were collected from 277 cattle of different breeds, ages, sex and faecal condition scores and examined using the sedimentation technique, quantitative real-time polymerase chain reaction (qPCR) and faecal antigen enzyme-linked immunosorbent assay (coproELISA). All samples were negative for bovine fasciolosis using coproELISA. A total of 73 (26.4%) samples were positive using the qPCR, while 36 were positive using the sedimentation technique, with low faecal egg counts (1 to 20 eggs per gram). The qPCR detected the highest positivity (26.4%, 95% CI 21.3, 32.0) followed by the sedimentation test (13.0%; 95% CI 9.3, 17.5). Location, breed, sex, age and faecal consistency score were not associated with positive qPCR results (p > 0.05). There was also no significant agreement (kappa = −0.011, p = 0.843) between qPCR and the sedimentation technique for the detection of Fasciola spp. The qPCR appeared to be the most sensitive method for detection of Fasciola spp. Further studies are required on the characterisation of Fasciola spp. in communal cattle in South Africa.

Potential Hybridization of Fasciola hepatica and F. gigantica in Africa-A Scoping Review

The occurrence of Fasciola gigantica and F. hepatica in Africa is well documented; however, unlike in Asia, there is a paucity of information on the existence of hybrids or parthenogenetic species on the continent. Nonetheless, these hybrid species may have beneficial characteristics, such as increased host range and pathogenicity. This study provides evidence of the potential existence of Fasciola hybrids in Africa. A literature search of articles published between 1980 and 2022 was conducted in PubMed, Google Scholar, and Science Direct using a combination of search terms and Boolean operators. Fasciola species were documented in 26 African countries with F. hepatica being restricted to 12 countries, whilst F. gigantica occurred in 24 countries, identified based on morphological features of adult Fasciola specimens or eggs and molecular techniques. The co-occurrence of both species was reported in 11 countries. However, the occurrence of potential Fasciola hybrids was only confirmed in Egypt and Chad but is suspected in South Africa and Zimbabwe. These were identified based on liver fluke morphometrics, assessment of the sperms in the seminal vesicle, and molecular techniques. The occurrence of intermediate host snails Galba truncatula and Radix natalensis was reported in Ethiopia, Egypt, South Africa, Tanzania, and Uganda, where F. hepatica and F. gigantica co-occurrences were reported. The invasive Pseudosuccinea columella snails naturally infected with F. gigantica were documented in South Africa and Egypt. In Zimbabwe, P. columella was infected with a presumed parthenogenetic Fasciola. This suggests that the invasive species might also be contributing to the overlapping distributions of the two Fasciola species since it can transmit both species. Notwithstanding the limited studies in Africa, the potential existence of Fasciola hybrids in Africa is real and might mimic scenarios in Asia, where parthenogenetic Fasciola exist in most Asian countries. In South Africa, aspermic F. hepatica and Fasciola sp. have been reported already, and Fasciola hybrids have been reported? in Chad and Egypt. Thus, the authors recommend future surveys using molecular markers recommended to identify Fasciola spp. and their snail intermediate hosts to demarcate areas of overlapping distribution where Fasciola hybrids and/or parthenogenetic Fasciola may occur. Further studies should also be conducted to determine the presence and role of P. columella in the transmission of Fasciola spp. in these geographical overlaps to help prevent parasite spillbacks.

Variability of Calodium hepaticum eggs from sigmodontine host species through geometric morphometric analysis

Calodium hepaticum is a zoonotic nematode with a worldwide distribution. Although the host range of C. hepaticum includes a wide spectrum of mammals (including humans), this parasite is predominantly associated with the families Muridae and Cricetidae. Several Sigmodontinae species from Argentina were found to be infected by C. hepaticum, with a high prevalence in Akodon azarae. The present study focuses on C. hepaticum eggs from natural infection of three species of sigmodontine rodents from Argentina. Eggs were genetically characterized (intergenic 18S rRNA region). The objectives of this work are: (i) to propose a new analytical methodology; and (ii) to morphologically characterize C. hepaticum eggs, from three Sigmodontinae species (A. azarae, Calomys callidus and Oligoryzomys flavescens). Analyses were made by the Computer Image Analysis System based on the new standardized measurements and geometric morphometric tools. The resulting factor maps clearly illustrate global size differences in the parasite eggs from the three Sigmodontinae species analysed. The degree of similarity between egg populations was assessed through pairwise Mahalanobis distances, showing that the largest distances were detected between parasite eggs from C. callidus and O. flavescens. Herein, the phenotypical plasticity of C. hepaticum eggs is shown. Significant positive correlations were obtained between each egg parasite principal component 1 and rodent corporal characteristics: weight; liver weight; rodent length; and rodent body condition. The usefulness of the geometric morphometric analysis in studies of the relationship between C. hepaticum and its host must be highlighted. The high prevalence observed in A. azarae, associated with the wide size range of the parasite eggs evidenced by principal component analysis, suggests A. azarae to be the Sigmodontinae host species that plays the most important role as reservoir host for C. hepaticum in the New World.

New Insights Into the Genetic Variability of Fasciola Hepatica (Trematoda) in Algeria and Relationships with Other Geographic Regions Revealed By Mitochondrial DNA

This study aims to investigate the level of genetic variability of Fasciola hepatica flukes isolated from cattle in Algeria and to determine the phylogenetic and phylogeographic relationships with sequences isolated worldwide. Mitochondrial (Cytochrome c Oxidase subunit I gene - COI) and nuclear markers (Internal Transcribed Spacers of nuclear ribosomal DNA - ITS) for 24 F. hepatica flukes isolated from 12 cattle in North Algeria were characterised. Only two haplotypes were obtained for the COI gene, resulting in a low level of genetic variation. The analysis of variation among the COI sequences isolated from around the world did not show high levels of genetic divergence, and the phylogenetic analysis revealed a genetic similarity among F. hepatica isolates from different areas of the world. The analysis of the ITS region showed a low level of variability, which prevented obtaining informative phylogenetic and phylogeographic results. The present study also revealed that specimens of F. hepatica are genetically similar in different hosts, indicating that the genetic structure among populations of this parasite is not influenced by the host species. The low levels of genetic variation for COI and ITS regions among fluke isolates from all continents are consistent with a common origin for the flukes’ worldwide distribution.

Molecular characteristics and genetic diversity of Fasciola hepatica from sheep in Xinjiang, China

Introduction

Fasciola hepatica is a trematode infecting ruminants worldwide and occasionally affecting other animal species, including humans. It causes significant economic losses. Geographic distribution and patterns of infection must be considered before control and management measures are developed for this parasite. DNA molecular markers are useful for the identification of flukes and elucidation of their genetic evolution. Therefore, the population structure of F. hepatica was studied using this method in sheep in Xinjiang, China.

Material and Methods

The molecular characteristics, genetic relationships within the population and dispersal patterns of F. hepatica isolates were analysed based on the cox1 and nad1 genes. The population structure of F. hepatica from three regions of Xinjiang was explored and a neutrality test was conducted.

Results

The cox1 and nad1 genes have 21 and 42 variable sites, respectively, which can be classified into 34 and 33 haplotypes. Median-joining network and phylogenetic tree analyses showed that there was no significant variation in F. hepatica isolates between the three geographical regions. Analysis of variance revealed that the genetic variation of F. hepatica was mainly present within the populations. The neutrality test indicated that the populations were relatively stable but the Hami population may have undergone short-term expansion.

Conclusion

This study revealed for the first time the molecular characteristics, genetic diversity and dispersal patterns of F. hepatica isolates from sheep in Xinjiang, thus providing new insights into the genetic variation and haplotype diversity of F. hepatica from indigenous sheep.

Laboratory analysis as support to slaughterhouse inspection in Songea cattle abattoir (Tanzania): A public health perspective

Livestock breeding is one of the main agricultural activities in Tanzania, recognized as one of the African countries with the greatest livestock resources. Cattle is the most widely bred animal species, especially with traditional farming methods such as pastoralism and agro-pastoralism. Slaughtering takes place mainly in rural slaughter slabs and municipal slaughterhouses, and according to local legislation it must be supervised by Official Veterinarians, who report any organs to be discarded and, after stamping the carcass, authorize its free consumption. Since the Ruvuma region lacks data on cattle diseases, the aim of this study was to collect information at Songea slaughterhouse, with particular attention to conditions of parasitic aetiology and potential zoonotic interest, deepening inspective diagnoses by means of parasitological and histological investigations on tissue samples. Overall, the slaughter data of 614 animals are reported. In most cases slaughtered cattle belonged to local breeds and came from the Mbeya region. Fasciolosis (diagnosed in 44.6% of animals) was the most frequent condition, followed by respiratory diseases (24.4%), aortic onchocerciasis (6.5%), hydatidosis (5.5%) and bovine cysticercosis (3.4%). Laboratory analysis identified Fasciola gigantica as the species involved in hepatic distomatosis in this area. Cases macroscopically ascribed to cysticercosis turned out to be a muscular form of onchocerciasis (by Onchocerca dukei), a neglected and unrecognised parasitic disease in Tanzania, questioning the real frequence of a zoonosis that causes primarily major economic losses. Pulmonary cysts, referred as hydatidosis at visual inspection, were histologically identified as haemal nodes, lymphoid organs common in ruminants, but described in cattle lungs for the first time in the present paper. Slaughterhouse is an important epidemiological observatory, especially for neglected parasitoses. The possibility of having basic laboratory diagnostics as an aid to visual inspection can ensure greater efficiency of veterinary services in the control of important livestock diseases and zoonoses, in the frame of a One Health perspective.

Identification of Fasciola spp. based on ITS-2 reveals the Fasciola gigantica infection in buffaloes in Nanning city, South China

Fasciolosis is harmful to ruminant husbandry worldwide. Given the superficial survey on Fasciolosis infection in Guangxi, the main buffalo breeding area in China, an in-depth investigation in the infection of buffaloes in Nanning, the capital of Guangxi Zhuang Autonomous Region, with Fasciola (Platyhelminthes: Trematoda: Digenea) species will provide a theoretical support for the control and prevention of Fasciolosis infection in buffaloes. Five water buffalo livers were collected from an abattoir in Nanning every 2 weeks from June 2018 to April 2019, and a total of 101 livers were obtained. All livers were then dissected to observe the liver lesions caused by the flukes. Afterwards, Fasciola spp. collected from Fasciolosis-infected livers were numbered and measured. Then, the livers infected with more than 3 flukes were marked, and 3 flukes were picked from each liver according to their morphological differences, such as body length (BL), body maximum width (BW) and length-width ratio (BL/BW). Moreover, these Fasciola spp. worms were selected for molecular biological analysis. The second internal transcribed spacer (ITS-2) of nuclear ribosomal DNA (rDNA) was amplified by polymerase chain reaction (PCR) and sequenced. Finally, sequential and phylogenetic analyses were also performed. The infection rate was 38.6 % according to anatomic examination, and the livers infected by Fasciola spp. were damaged seriously. The principal manifestations were the enlargement of the liver and protrusion of the bile ducts. In some cases, the bile duct wall became inflamed and rough, in which some sediment such as phosphate could be easily found. After dissection, 1243 Fasciola spp. flukes were collected from 39 out of 101 livers. The morphometric measurements obtained from the present study showed that the BL/BW ranged from 1.42-10.25. However, it might vary considerably among different geographical locations and could not be used as an accurate method for the identification of Fasciola spp.. Analysis of the ITS-2 sequences showed that 83 out of 87 flukes had 100 % homology with each other, and the other 4 flukes with 99.3 % homology possessed a nucleotide polymorphism. A unique position (271) was detected in flukes in Nanning isolates. Phylogenetic analysis indicated that all the flukes were Fasciola gigantica, and no Fasciola hepatica or the intermediate form was found in this study.

First morphogenetic analysis of parasite eggs from Schistosomiasis haematobium infected sub-Saharan migrants in Spain and proposal for a new standardised study methodology

Schistosomiasis is a Neglected Tropical Disease caused by trematode species of the genus Schistosoma. Both, autochthonous and imported cases of urogenital schistosomiasis have been described in Europe. The present study focuses on eggs, considered pure S. haematobium by genetic characterisation (intergenic ITS region of the rDNA and cox1 mtDNA). A phenotypic characterisation of S. haematobium eggs was made by morphometric comparison with experimental populations of S. bovis and S. mansoni, to help in the diagnosis of S. haematobium populations infecting sub-Saharan migrants in Spain. Analyses were made by Computer Image Analysis System (CIAS) applied on the basis of new standardised measurements and geometric morphometric tools. The principal component analysis (PCA), including seventeen non-redundant measurements, showed three phenotypic patterns in eggs of S. haematobium, S. bovis and S. mansoni. PCA showed that the S. bovis population presented a large egg size range with a pronouncedly larger maximum size. Similarly, S. bovis shows bigger spine values than S. haematobium. Mahalanobis distances between each pair of groups were calculated for each discriminant analysis performed. In general, S. mansoni and S. bovis present larger distances between them than with S. haematobium, i.e. they present the greatest differences. Regarding the spine, S. haematobium and S. mansoni are the most distant species. Results show the usefulness of this methodology for the phenotypic differentiation between eggs from these Schistosoma species, capable of discerning morphologically close eggs, as is the case of the haematobium group. Schistosoma egg phenotyping approaches may be applied to assess not only hybrid forms but also potential influences of a variety of other factors.

Very High Fascioliasis Intensities in Schoolchildren from Nile Delta Governorates, Egypt: The Old World Highest Burdens Found in Lowlands

Quantitative coprological analyses of children were performed in Alexandria and Behera governorates, Egypt, to ascertain whether individual intensities in the Nile Delta lowlands reach high levels as those known in hyperendemic highland areas of Latin America. Analyses focused on subjects presenting intensities higher than 400 eggs per gram of faeces (epg), the high burden cut-off according to WHO classification. A total of 96 children were found to shed between 408 and 2304 epg, with arithmetic and geometric means of 699.5 and 629.07 epg, respectively. Intensities found are the highest hitherto recorded in Egypt, and also in the whole Old World. A total of 38 (39.6%) were males and 58 (60.4%) were females, with high intensities according to gender following a negative binomial distribution. The high burden distribution shows a peak in the 7-10 year-old children group, more precocious in females than males. Results showed high burdens in winter to be remarkably higher than those known in summer. The fascioliasis scenario in Egyptian lowlands shows similarities to highlands of Bolivia and Peru. Diagnostic methods, pathogenicity and morbidity in high burdens should be considered. The need for an appropriate quantitative assessment of heavy infected children to avoid post-treatment colic episodes is highlighted.

DNA Multi-Marker Genotyping and CIAS Morphometric Phenotyping of Fasciola gigantica-Sized Flukes from Ecuador, with an Analysis of the Radix Absence in the New World and the Evolutionary Lymnaeid Snail Vector Filter

Simple Summary

Fasciolid flukes collected from sheep and cattle in Ecuador showed a high diversity in DNA sequences whose analyses indicated introductions from South America, European and North American countries. These results agree with the numerous livestock importations performed by Ecuador. Abnormally big-sized liver flukes were found in Ecuadorian sheep. The morphometric phenotypic CIAS study showed that its size maximum and mean very pronouncedly and significantly surpassed those of the Fasciola hepatica populations from South America and Spain and proved to be intermediate between standard F. hepatica and F. gigantica populations. Such a feature is only known in intermediate fasciolid forms in Old World areas where the two species and their specific lymnaeid snail vectors overlap. This argues about a past hybridization after F. gigantica importation from Pakistan and/or introduction of intermediate hybrids previously generated in USA. The lack of heterozygotic rDNA ITS positions differentiating the two species, and of introgressed fragments and heteroplasmic positions in mtDNA genes, indicate a post-hybridization period sufficiently long as for rDNA concerted evolution to complete homogenization and mtDNA to return to homoplasmy. The vector specificity filter due to Radix absence should act as a driving force in accelerating such lineage evolution. Public health implications are finally emphasized.

Abstract

Fascioliasis is a disease caused by Fasciola hepatica worldwide transmitted by lymnaeid snails mainly of the Galba/Fossaria group and F. gigantica restricted to parts of Africa and Asia and transmitted by Radix lymnaeids. Concern has recently risen regarding the high pathogenicity and human infection capacity of F. gigantica. Abnormally big-sized fasciolids were found infecting sheep in Ecuador, the only South American country where F. gigantica has been reported. Their phenotypic comparison with F. hepatica infecting sheep from Peru, Bolivia and Spain, and F. gigantica from Egypt and Vietnam demonstrated the Ecuadorian fasciolids to have size-linked parameters of F. gigantica. Genotyping of these big-sized fasciolids by rDNA ITS-2 and ITS-1 and mtDNA cox1 and nad1 and their comparison with other countries proved the big-sized fasciolids to belong to F. hepatica. Neither heterozygotic ITS position differentiated the two species, and no introgressed fragments and heteroplasmic positions in mtDNA were found. The haplotype diversity indicates introductions mainly from other South American countries, Europe and North America. Big-sized fasciolids from Ecuador and USA are considered to be consequences of F.gigantica introductions by past livestock importations. The vector specificity filter due to Radix absence should act as driving force in the evolution in such lineages.

Molecular identification and genetic-polymorphism analysis of Fasciola flukes in Dali Prefecture, Yunnan Province, China

This study aimed to identify species of Fasciola flukes in Dali Prefecture (Yunnan Province, China) and analyze their genetic diversity. Fasciola flukes (n = 122) were collected from cattle livers in a farmers' market in Xiaguan Town, Dali Prefecture. Nucleotide sequences of ribosomal internal transcribed spacer (ITS) as well as nicotinamide adenine dinucleotide dehydrogenase subunit 1 (ND1) and mitochondrial cytochrome c oxidase subunit 1 (CO1) were amplified, sequenced, and subjected to homology analysis. The heterozygosity ratios of different ITS alleles were determined using the peak-height ratio of heterozygous loci. Multiplex PCR analysis of the nuclear protein coding gene, phosphoenolpyruvate carboxykinase (pepck), was used to identify Fasciola species. Multiple ND1 sequence alignments enabled further genetic diversity analysis of regional Fasciola flukes. Seven ITS sequences belonged to F. hepatica and 115 belonged to Fh/Fg heterozygous flukes. Sequencing analysis of heterozygous flukes revealed 11 heterozygous loci with double peaks, with significantly variable ratios among individuals. ND1 and CO1 results indicated that one specimen was identical to F. hepatica, while 121 specimens were identical to F. gigantica or contained one variable site. Multiplex PCR results for pepck showed that double bands for F. hepatica and F. gigantica were amplified from Dali Fasciola specimens; hence, they were all heterozygous. By combining ITS, ND1, and CO1 sequences with multiplex pepck PCR results, all 122 specimens were identified as Fh/Fg heterozygous Fasciola flukes. Our experimental results preliminarily confirmed a high degree of Fh/Fg heterozygosity among Fasciola flukes in the Dali area. Selecting multiple molecular markers for concurrent analysis will provide more comprehensive and accurate genetic information.

Enzyme-linked immunosorbent assay (ELISA) using recombinant Fasciola cathepsin L1 for the diagnosis of human fasciolosis caused by Fasciola hepatica/gigantica hybrid type

Recombinant Fasciola cathepsin L-1 (rCatL1) was evaluated in enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of human fasciolosis in Japan. Quality characteristics of the test were accessed by receiver operating characteristic (ROC) analysis, with sera from fasciolosis patients (n = 10), patients with no evidence of parasitic infections (n = 29), and patients with other helminth infections (n = 119). Both the sensitivity and specificity of the test achieved 100% with the control samples. To test the performance of the assay in an authentic situation, 311 serum samples, which had been sent to our laboratory for the diagnosis of parasitic infections from January 2018 to February 2019, were re-assessed using the rCatL1 ELISA. In this case, the sensitivity of the rCatL1 ELISA was 100%, giving positive results to all fasciolosis sera (n = 7), and the specificity was 99.0%, in which three of the 304 non-fasciolosis samples were judged positive. Careful re-examination of the laboratory data and medical imaging of these three patients revealed that one of the patients, who had been diagnosed as having larva migrans syndrome, was judged to be infected with Fasciola, in addition to ascarid nematodes. Thus the true specificity of the assay in the authentic reached 99.3% (302/304). As the rCatL1 ELISA exhibited a highly significant positive likelihood ratio (152.0) and negative likelihood ratio (0.0), calculated from the 311 sample data, this rCatL1 ELISA can be used for routine screening and definitive diagnosis test for fasciolosis in reference laboratories.

Morphological and molecular characterization of Fasciola hepatica and Fasciola gigantica phenotypes from co-endemic localities in Mpumalanga and KwaZulu-Natal provinces of South Africa

Fasciolosis is a food- and water-borne disease caused by digenean trematode species, Fasciola hepatica and F. gigantica. They are widely distributed and infect a wide range of definitive hosts, causing enormous economic loss due to reduced productivity in domestic ruminants. The two species have been previously reported to be co-endemic in KwaZulu-Natal and Mpumalanga provinces of South Africa. Hybridization between the two species has been reported elsewhere. Despite the overlap of the two species in two provinces, there has been no attempt to determine the presence of the intermediate forms or hybrids. Therefore, this study aimed at morphological and molecular characterization of Fasciola spp. collected from cattle slaughtered at abattoirs located in the two provinces of South Africa, where two species are endemic. A total of 71 fluke specimens were collected cattle from abattoirs in Enhlazeni and Nelspruit in Mpumalanga province and Pietermaritzburg in KwaZulu-Natal province of South Africa, and Zimbabwe (Bulawayo abattoir). Fasciola gigantica specimen collected from Zimbabwe where it has been confirmed as the only species occurring and this was used as control in the morphological and molecular assessment of the collected specimens. Of the 71 specimens collected, 37 were classified as F. hepatica, 12 as F. gigantica and 22 as Fasciola spp using morphological characters. Of these species, 11 of 37 F. hepatica and 6 of 22 Fasciola sp were found to be aspermic or having very scanty sperm. Fifteen flukes which were spermatic were all identified morphologically as F. gigantica whilst 5 flukes which were aspermic were identified morphologically as F. hepatica. Molecular analysis of the same 15 spermatic specimens confirmed the presence of F. hepatica (n = 9) and F. gigantica (n = 6) using the CO1 marker and as F. hepatica (n = 4), F. gigantica (n = 7) and Fasciola sp. (n = 1) for the same specimens using the ITS-1/5.8S/ITS-2 marker. The remaining 4 aspermic flukes (one did not resolve) were all identified morphologically as F. hepatica and molecular analysis confirmed them as F. hepatica (n = 4) by both CO1 and ITS-1/5.8S/ITS-2. Phylogenetic analysis based on both CO1 and ITS-1/5.8S/ITS-2 showed that F. hepatica species formed a moderately supported monophyletic clade with F. gigantica. Their ancestral history was further confirmed by haplotype network, which formed novel haplotypes that corresponded with the structure of the phylogenetic tree. Results from this study showed that morphological characters alone have limitations in identifying F. hepatica and F. gigantica in areas where the two species occur, although both methods confirmed the presence of F. gigantica occurring in Zimbabwe, F. hepatica in KwaZulu-Natal, and both species occurring in Mpumalanga province. Therefore, the use of morphological techniques, complemented by molecular techniques are recommended, especially in endemic areas where the two species are co-endemic.

Comparative analysis of the mitochondrial proteins reveals complex structural and functional relationships in Fasciola species

Mitochondria is a cellular source of energy, appears to play an essential role in dealing with cellular stress induced by environmental stimuli. The genetic diversity of mitochondrial genes involved in oxidative phosphorylation affecting the production of cellular energy and regional adaptation to various ecological (climatic) pressures affecting amino acid sequences (variants of protein). However, little is known about the combined effect of protein changes on cell-level metabolic alterations in simultaneous exposure to various environmental conditions, including mitochondrial dysfunction and oxidative stress induction. The present study was designed to address this issue by analyzing the mitochondrial proteins in Fasciola species including Cytochrome oxidase (COX1, COX2, COX3, and CYTB) and NADH dehydrogenase (ND1, ND2, ND3, ND4, ND5, and ND6). Mitochondrial proteins were used for detailed computational investigation, using available standard bioinformatics tools to exploit structural and functional relationships. These proteins in Fasciola hepatica, Fasciola gigentica, and Fasciola jacksoni were functionally annotated using public databases. The results showed that the protein of COX1 of F. hepatica, F. gigantica, and F. jacksoni consist of 510, 513, and 517 amino acids, respectively. The alignment of proteins showed that these proteins are conserved in the same regions at ten positions in COX and CYTB proteins while at twelve locations in NADH. Three-dimensional structure of COX, CYTB, and NADH proteins were compared and showed differences in additional conserved and binding sites in COX and CYTB proteins as compared to NADH in three species of Fasciola. These results based on the amino acid diversity pattern were used to identify sites in the enzyme and the variations in mitochondrial proteins among Fasciola species. Our study provides valuable information for future experimental studies, including identification of therapeutic, diagnostic, and immunoprophylactic interests with novel mitochondrial proteins.

Molecular Characterization of Fasciola spp. from a Donkey (Equus asinus) Using Partial Sequencing of cox1 and nad1

Background

Fasciola hepatica as an important parasite affects health of humans and animals in some tropical and subtropical areas of the world, including Iran. Little is known about the molecular diversity of Fasciola in Equidae. Therefore, this study aimed to characterize the genetic polymorphisms among parasites.

Methods

Eight adult Fasciola spp. isolates were collected from a working donkey after necropsy in Shiraz, southwestern Iran, in 2018. Primarily, various parameters were measured morphologically. Subsequently, DNA was extracted from each fluke and molecular markers of cytochrome C oxidase (cox1) and NADH dehydrogenase 1(nad1) from individual Fasciola isolates were amplified using PCR assay and sequence data were employed for molecular and phylogenetic analysis. Genetic diversity between isolates was evaluated by comparing the sequences of these two mitochondrial regions.

Results

Based on the morphological and analyzed mitochondrial sequences, all of eight donkey isolates (100%) were identified as F. hepatica. Moreover, nine and five nucleotide polymorphisms were identified in the cox1and nad1 region sequences, respectively.

Conclusion

Accordingly, phylogenetic data revealed five and four haplotypes among donkey isolates based on the cox1and nad1 markers. Similarly, some of these haplotypes have been previously reported from different host species in Iran as well as all around the world.

Effectiveness of Fasciola gigantica excretory-secretory and recombinant cathepsin L antigens for rapid diagnosis of human fascioliasis using immunochromatographic devices

Fascioliasis, a food- and water-borne trematodiasis, has been identified as a public health threat by the World Health Organization, with millions of people estimated to be infected or at risk of infection worldwide. We developed an immunochromatographic test (ICT) as a point-of-care (POC) tool for the rapid serodiagnosis of human fascioliasis caused by Fasciola gigantica and evaluated their diagnostic ability. Two tests were developed using antigens from adult F. gigantica excretory-secretory (ES) product and recombinant F. gigantica cathepsin L (rFgCL). Sera from 12 patients with parasitologically proven fascioliasis caused by F. gigantica, 18 with clinically suspected fascioliasis, 65 with other parasitic infections, and 30 healthy controls were used. Using a cutoff of > 0.5 for antibody detection, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the ES-based ICT method were 100%, 98.9% 96.8%, 100%, and 99.2%, respectively, and those of the rFgCL-based ICT method were 86.7%, 93.7%, 81.3%, 95.7%, and 92.0%, respectively. The concordance between the two methods was 91.2%. Tests using F. gigantica ES and rFgCL antigens can be employed quickly and easily as POC diagnostic tools. They can be used to support the clinical diagnosis of human fascioliasis gigantica and in large-scale surveys in endemic areas throughout tropical regions without necessitating additional facilities or ancillary supplies.

Molecular Confirmation of a Fasciola gigantica × Fasciola hepatica Hybrid in a Chadian Bovine

Fascioliasis is a zoonotic infection of humans and, more commonly, ruminants. It is caused by 2 liver fluke species, Fasciola hepatica and Fasciola gigantica, which differ in size. The traditional morphological methods used to distinguish the 2 species can be unreliable, particularly in the presence of hybrids between the 2 species. The development of advanced molecular methods has allowed for more definitive identification of Fasciola species, including their hybrids. Hybrids are of concern, as it is thought that they could acquire advantageous traits such as increased pathogenicity and host range. In 2013, we collected flukes from Fasciola-positive cattle, sheep, and goats slaughtered in 4 Chadian abattoirs. DNA from 27 flukes was extracted, amplified, and analyzed to identify species using the ITS1+2 locus. Twenty-six of the 27 flukes were identified as F. gigantica, while the remaining fluke showed heterozygosity at all variable sites that distinguish F. hepatica and F. gigantica. Cloning and sequencing of both alleles confirmed the presence of 1 F. hepatica and 1 F. gigantica allele. To our knowledge, this is the first unambiguous, molecular demonstration of the presence of such a hybrid in a bovine in sub-Saharan Africa.

Occurrence, Morphometric, and Molecular Investigation of Cattle and Buffalo Liver Adult Fluke in Peninsular Malaysia Main Abattoirs

Fascioliasis is a parasitic disease of human and animal caused by Fasciola gigantica (F. gigantica) and Fasciola hepatica (F. hepatica). More than 700 million of grazing animals and over 180 million human population are at the risk of fascioliasis. This study was conducted in Banting, Ipoh, Shah Alam, and Taiping abattoirs within Peninsular Malaysia to determine the occurrence and identify the species of liver flukes, causing liver condemnation in cattle and buffaloes. Within a study period from January to December 2018, a total of 25 condemned bovine livers were collected from Banting, Ipoh, Shah Alam, and Taiping abattoirs and analyzed. Taiping abattoir had the highest occurrence of fascioliasis [14/1014 (1.38%)], and Shah Alam abattoir had the least occurrence [1/3377 (0.03%)]. From all the sampled livers, the average number of adult flukes recorded ranged from 1 to 83. A total of 440 adult flukes were studied morphometrically, using parameters such as body length (BL), body width (BW), cone length (CL), cone width (CL), body area (BA), body perimeter (BP), the distance between the ventral sucker and posterior end of body (VS-P), BL/BW ratio, BL/V-SP, and body roundness (BR). Furthermore, molecular analysis was conducted using PCR-RFLP methods to distinguish between F. gigantica and F. hepatica involving ITS1 primer and RsaI restriction enzyme. RFLP pattern with RsaI produced a consistent pattern of 360,100 and 60 bp fragments in F. hepatica, whereas F. gigantica worms had a profile of 360,170, and 60 bp in size. The morphometric and molecular analysis results indicated that cattle and buffaloes slaughtered at Banting, Shah Alam, Taiping, and Ipoh abattoirs were infected with F. gigantica.

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

Fasciola hepatica, Fasciola gigantica, and Fascioloides magna are liver flukes causing disease in cattle and sheep. Damage to the liver due to F hepatica and F gigantica results in clinical disease and/or production losses. F magna seems to have little effect in cattle but causes high mortality in sheep. The fluke life cycle involves an aquatic or amphibious snail intermediate host and thus requires suitable moisture and temperature conditions. F magna requires the presence of deer. Drug treatment is the mainstay of control and needs to be applied considering the life cycle and epidemiology of the parasite.

Description and phylogenetic analyses of ribosomal transcription units from species of Fasciolidae (Platyhelminthes: Digenea)

Many members of Fasciolidae are common trematodes in cattle, buffaloes, sheep, elephants, pigs, with some capable of infecting humans also. In this study, the complete or near-complete sequences of ribosomal transcription unit (rTU or rDNA), each of Fasciola hepatica (Australia), Fascioloides jacksoni (Sri Lanka), Fasciolopsis buski (Vietnam) and three isolates of F. gigantica (Vietnam), were obtained and characterized. The full length of rDNA for each F. hepatica, 'hybrid' Fasciola sp., Fas. jacksoni and Fa. Buski, was 7657 bp, 7966 bp, 7781 bp and 8361 bp, with the complete intergenic spacer region (IGS) (862 bp, 1170 bp, 987 bp and 561 bp), respectively. The rDNA of two 'pure' F. gigantica isolates from Vietnam was 6794 bp with unsequenced IGS. For 28S rRNA genes the Fasciola spp. are equal, 1958 bp for 18S, 160 bp for 5.8S, 3863 bp and 454 bp for ITS1 but ITS2 differ by one nucleotide (Thymine) (359 or 360 bp). The ITS1 of the sensu lato Fa. buski has some distinguishable features, 286 bp for ITS2, 3862 bp for 28S and four repeat units of 356-361 bp each found in ITS1. The 28S rDNA analysis showed the lowest level of divergence (0-0.57%) between F. hepatica and F. gigantica and higher (2.23-2.62%) and highest (6-6.42%) for Fas. jacksoni and Fasciolopsis, respectively. The tree of 43 strains/species clearly produced a well-supported phylogeny, where 18 fasciolids consistently grouped, forming a discrete Fasciolidae clade, distinct from Philophthalmidae, Echinostomatidae and Echinochasmidae in Echinostomatoidea. Fascioloides jacksoni is outside Fasciola spp.: basal with Fas. magna, as previously demonstrated.

Fasciola gigantica, F. hepatica and Fasciola intermediate forms: geometric morphometrics and an artificial neural network to help morphological identification

Background

Fasciola hepatica and F. gigantica cause fascioliasis in both humans and livestock. Some adult specimens of Fasciola sp. referred to as “intermediate forms” based on their genetic traits, are also frequently reported. Simple morphological criteria are unreliable for their specific identification. In previous studies, promising phenotypic identification scores were obtained using morphometrics based on linear measurements (distances, angles, curves) between anatomical features. Such an approach is commonly termed “traditional” morphometrics, as opposed to “modern” morphometrics, which is based on the coordinates of anatomical points.

Methods

Here, we explored the possible improvements that modern methods of morphometrics, including landmark-based and outline-based approaches, could bring to solving the problem of the non-molecular identification of these parasites. F. gigantica and Fasciola intermediate forms suitable for morphometric characterization were selected from Thai strains following their molecular identification. Specimens of F. hepatica were obtained from the Liverpool School of Tropical Medicine (UK). Using these three taxa, we tested the taxonomic signal embedded in traditional linear measurements versus the coordinates of anatomical points (landmark- and outline-based approaches). Various statistical techniques of validated reclassification were used, based on either the shortest Mahalanobis distance, the maximum likelihood, or the artificial neural network method.

Results

Our results revealed that both traditional and modern morphometric approaches can help in the morphological identification of Fasciola sp. We showed that the accuracy of the traditional approach could be improved by selecting a subset of characters among the most contributive ones. The influence of size on discrimination by shape was much more important in traditional than in modern analyses. In our study, the modern approach provided different results according to the type of data: satisfactory when using pseudolandmarks (outlines), less satisfactory when using landmarks. The different reclassification methods provided approximately similar scores, with a special mention to the neural network, which allowed improvements in accuracy by combining data from both morphometric approaches.

Conclusion

We conclude that morphometrics, whether traditional or modern, represent a valuable tool to assist in Fasciola species recognition. The general level of accuracy is comparable among the various methods, but their demands on skills and time differ. Based on the outline method, our study could provide the first description of the shape differences between species, highlighting the more globular contours of the intermediate forms.

Multilocus approach reveals discordant molecular markers and corridors for gene flow between North African populations of Fasciola hepatica

Fasciolosis is a foodborne trematodosis characterised by a worldwide distribution. Various approaches have been developed for the study of the causative agents of this parasitic infection: Fasciola hepatica, Fasciola gigantica and the aspermic intermediated forms (hybrid and introgressed). In the present study, novel and common molecular markers (pepck and pold, ITS, CO1, ND1 and CO1-trnT-rrnL) were used to characterise Fasciola flukes from the Tunisian-Algerian border, to estimate the gene flow between these populations and to evaluate the reliability of different molecular markers. All nuclear and mitochondrial markers, apart from pepck, supported the monophyly of the studied flukes identified as F. hepatica. Multiplex PCR for pepck revealed three different genotypes corresponding to F. hepatica (pepck-Fh), F. gigantica (pepck-Fg) and the aspermic Fasciola flukes (pepck-Fh/Fg). Sequence analysis of pepck revealed high polymorphism, length variation, within this intronic marker. The observed inconsistencies were due to the position of the forward primer within the intronic region. Pepck sequences showed different level of heterozygosity and homozygosity with length polymorphisms in the introns. Pepck multiplex PCR patterns could not differentiate between Fasciola species. All studies based on only pepck multiplex PCR with mitochondrial markers should be revised. Nuclear and mitochondrial markers revealed an important gene flow between Tunisian and Algerian populations of F. hepatica. The combination of nuclear and mitochondrial sequence analysis is still the best method to distinguish these taxa. Effective measures are needed in order to better control cross-country illegal trade of vector.

Multigene typing and phylogenetic analysis of Fasciola from endemic foci in Iran

Fasciolosis is a public health problem originally transmitted from livestock. Although molecular analysis of the nuclear and mitochondrial genes allow discrimination between the two known species of Fasciola, F. hepatica and F. gigantica, these markers do not permit the detection of hybrid forms. On the other hand, molecular analysis of the pepck and pold genes from Fasciola do permit the detection of hybrid isolates and this study has not yet been performed on specimens from human and domesticated animals in Iran. Therefore, the aim of this study was to molecularly analyze Fasciola isolates using both conventional and the two new genetic markers mentioned above. Fifty-three adult Fasciola worms were isolated from the livers of 28 domesticated animals, including sheep, cattle and goat. Moreover, an adult worm was obtained from the bile duct of an infected woman during endoscopic retrograde cholangio-pancratography (ERCP). Targeted fragments from the ITS-1, NDI and COX1 genes were amplified using specific primers. PCR products were sequenced and genetically analyzed using MEGA v.7 and DnaSP software. Additionally, the pepck and pold regions were amplified and analyzed using multiplex PCR and RLFP-PCR, respectively. Multiple alignment of sequenced fragments showed highest similarity among the ITS-1 sequences isolated from all four hosts in comparison to the other genes. Furthermore, sequence diversity across the COX1 was higher than the NDI and ITS-1. Diversity among sequences isolated from cattle was higher than those from sheep and goat in all three genes. Tajima's D and Fu's Fs were negative and statistically significant for all the genes except ITS-1. Phylogenetic trees showed that the human F. hepatica isolate was closer to sheep isolates. The results of the pepck and pold analyses showed that all isolates were F. hepatica and there were no hybrid forms among samples. The molecular analyses corroborated this finding.

Phylogenetic analysis of Fasciola spp. isolated from slaughtered cattle in KwaZulu-Natal and Mpumalanga provinces of South Africa based on the cytochrome c oxidase subunit I mitochondrial marker

Fasciola spp. are the causative agents of fascioliasis in humans and livestock. Before the development of control and management measures, the geographical distribution of the species and patterns of infection must be considered. Because of difficulties in the phenotypic differentiation and morphometric classification of Fasciola spp., DNA molecular markers have become more useful for fluke differentiation and description of phylogenetic patterns. This study aimed to differentiate and describe the phylogenetic background of Fasciola spp. isolated from cattle slaughtered at three abattoirs in the Mpumalanga and KwaZulu-Natal provinces of South Africa. The cytochrome c oxidase I (COI) - FHCO1 (forward: 5'-TTGGTTTTTTGGGCATCCT-3') and FHCO1 (reverse: 5' -AGGCCACCACCAAATAAAAGA3') - marker was sequenced from 55 Fasciola flukes that were collected from abattoirs in catchment areas of the KwaZulu-Natal and Mpumalanga provinces. Fasciola hepatica was demonstrated to have 100% prevalence in KwaZulu-Natal and Mpumalanga (highveld), respectively, and 76% prevalence in the lowveld (Belfast area) of Mpumalanga. Two animals from the Belfast metapopulation were co-infected with both Fasciola gigantica and F. hepatica. DNA sequence analysis of all the isolates demonstrated a sequence conservation of 0.472, nucleotide diversity of 0.082 and Tajima's D of -1.100; however, it was not statistically significant (p > 0.05). Twenty-two haplotypes were identified, with 18 novel haplotypes being unique to the isolates from South Africa. Within the study samples, 12 haplotypes were isolated to a few individuals, with a haplotype diversity of 0.8957 indicating high genetic diversity. Principal coordinate analysis supported the clustering and distribution of the haplotypes, with 11.38% of the variation being attributed to coordinate 2 and 55.52% to coordinate 1. The distribution of Fasciola spp. has been demonstrated to be related to the distribution of the freshwater intermediate host snails, Lymnaea spp., as well as the relative altitude of the localities in South Africa. Information provided by this study serves as preliminary evidence for further studies on the mapping of the distribution of F. gigantica and F. hepatica in South Africa, which is key in designing control programmes for fascioliasis in humans and livestock.

Prevalence of fasciolosis in livestock and humans: A systematic review and meta-analysis in Iran

Fasciolosis is a re-emerging disease of livestock and rarely human, being endemic in Iran. Herein, we aimed to quantitatively assess the human seropositivity and prevalence of animal fasciolosis in our country. English and Persian databases were searched for online literature. In total, 10 human seroprevalence studies and 49 animal investigations were obtained from January 1999 to March 2019. Only animal studies were included in meta-analysis. The highest human seroprevalence was detected in Guilan province (326/452; 50%). The pooled prevalence of the animal infections was calculated as 6.2% (95% CI = 5.8%-6.5%). In detail, the prevalence ranges in three hosts included as 4.2% (95% CI = 3.8%-4.5%) in sheep, 9% (95% CI = 8.0%-9.9%) in cattle and 3.1% (95% CI = 2.4%-3.7%) in goat. The highest prevalence rate was observed in the north, 11.8% (95% CI = 8.4%-15.1%), while the lowest prevalence was detected in the central Iran with 1.8% (95% CI = 1.3%-2.3%). Egger's regression test revealed no significant publication bias (P = 0.307). Also, there was no remarkable correlation between weighted prevalence and sample size (P = 0.249) as well as year of study (P = 0.172). These findings would be necessary for better preventive strategies in case of human and animal Fasciola infections as well as snail intermediate hosts.

Evaluation of a Commercial Enzyme-Linked Immunosorbent Assay Kit and In-House Fasciola gigantica Cysteine Proteinases-Based Enzyme-Linked Immunosorbent Assays for Diagnosis of Human Fascioliasis

Fascioliasis, caused by Fasciola hepatica and Fasciola gigantica infection, is a major food-borne trematodiasis in many places of the world, with the central region of Vietnam being reported as a highly endemic area. Stool examination for Fasciola eggs is not a sensitive method, and immunodiagnostic methods are preferable. We investigated various enzyme-linked immunosorbent assays (ELISAs) to evaluate their efficacy for fascioliasis diagnosis. Test sera used are primarily screened using an ELISA kit produced in Vietnam (VN kit; Viet Sinh Chemical Producing & Trading Co. Ltd., Ho Chi Minh City, Vietnam): Seropositive individuals having symptoms compatible with fascioliasis were regarded as clinically diagnosed fascioliasis cases. A commercial Fasciola IgG ELISA kit from Diagnostic Automation/Cortez Diagnostics, Inc. (USA kit; Woodland Hills, CA), which has been commonly used in Vietnam, was assessed and compared with in-house ELISA systems, including a cystatin-capture (CC) ELISA using crude worm extract (CWE) and an indirect ELISA using a synthetic peptide Ac-TPTCHWECQVGYNKTYDEE-NHMe designed from the F. gigantica cathepsin B (FgCB5) molecule. The USA kit was suitable for routine diagnosis after recalibration of the manufacturer's suggested cutoff point. Cystatin-capture ELISA with CWE provided good sensitivity and specificity with perfect agreement to the results of the USA kit. In dot-blot ELISA, recombinant FgCB5 reacted more strongly with human antisera than did other F. gigantica antigens tested. Enzyme-linked immunosorbent assay using the synthetic peptide fragment of the FgCB5 exhibited nearly 80% sensitivity and specificity, but the test results showed low agreement with CC-ELISA or the USA kit. In conclusion, the commercially available Fasciola IgG ELISA kit from the United States and the in-house CC ELISA using CWE are suitable for practical diagnosis for fascioliasis.

Fascioliasis

Fascioliasis is a major parasitic disease caused by the digenetic trematodes Fasciola hepatica and Fasciola gigantica. The disease is a well-known veterinary problem of worldwide distribution. Fascioliasis is the vector-borne parasitic disease presenting the widest latitudinal, longitudinal, and altitudinal distribution known at present. In the last two decades, many surveys have shown it to be an important public health problem as well, including estimations of 2.4 million, up to 17 million people, or even higher depending on the hitherto unknown situations mainly in several regions of Asia and Africa. In recent years, the increasing number of human case reports in many countries of the five continents and the results of studies on pathogenicity and immunity, mainly regarding the chronic period of the disease, were the reasons why it was decided to no longer consider fascioliasis merely a secondary zoonotic disease but an important human parasitic disease. In this chapter, we review the most relevant features in relation to fascioliasis, including from the most traditional to the most innovative aspects.

Histopathological findings of Fasciola hepatica infection in non-native European hare (Lepus europaeus) in Southern Chile

Fasciola hepatica is a parasite introduced in America from Europe, being considered of concern for public health and animal production, especially in countries with endemic areas as occur in Chile. In this country, the research has been focused mainly in domestic ruminants, with native and introduced wildlife being largely ignored. Thus, the aim of this study was to report the infection by Fasciola hepatica in an introduced mammal, the European hare, which is distributed along a vast area of the country. One in 42 hares hunted showed histological lesions compatible with F. hepatica, and harbored a parasitic load of 6 liver flukes. This is the first report of this lagomorph acting as host of this helminth in the country and the third in South America. Yet, we found no previous reports regard the pathology of this fluke in the species. Thus, we emphasize the importance of more studies regarding introduced mammals which could be acting as reservoirs for this important fluke.

Distribution Status of Hybrid Types in Large Liver Flukes, Fasciola Species (Digenea: Fasciolidae), from Ruminants and Humans in Vietnam

The aim of this study is to delineate ‘admixed hybrid’ and ‘introgressive’ Fasciola genotypes present in the Fasciola population in Vietnam. Adult liver flukes collected from ruminants in 18 Provinces were morphologically sorted out by naked eyes for small (S), medium (M) and large (L) body shapes; and human samples (n=14) from patients. Nuclear ribosomal (rDNA) ITS1 and ITS2, and mitochondrial (mtDNA) nad1 markers were used for determination of their genetic status. Total 4,725 worm samples of ruminants were tentatively classified by their size: 6% (n=284) small (S)-, 13% (n=614) medium (M)-, and 81% (n=3,827) large (L)-forms. All the representative (n=120, as 40 each group) and 14 human specimens, possessed maternal mtDNA of only F. gigantica and none of F. hepatica. Paternally, all (100%) of the L-(n=40) and 77.5% (n=31) of the M-flukes had single F. gigantica rDNA indicating ‘pure’ F. gigantica. A majority (90%, n=36) of the S- and 15% (n=6) of the M-worms had single F. hepatica rDNA, indicating their introgressive; the rest (10%, n=4) of the S- and 7.5% (n=3) of the M-flukes had mixture of both F. gigantica and F. hepatica rDNAs, confirming their admixed hybrid genetic status. Fourteen human samples revealed 9 (64%) of pure F. gigantica, 3 (22%) of introgressive and 2 (14%) of admixed hybrid Fasciola spp. By the present study, it was confirmed that the small worms, which are morphologically identical with F. hepatica, are admixed and/or introgressive hybrids of Fasciola spp., and able to be the pathogens of human fascioliasis.

Genetic characterisation of Fasciola gigantica from Ghana

Fasciola hepatica and Fasciola gigantica are the causal agents of the zoonotic food-born disease fascioliasis. Africa is primarily endemic to F. gigantica, although sympatric presence of F. hepatica is known for some countries. The present situation of fascioliasis in western Africa, and Ghana in particular, is still poorly understood, and studies including molecular identification of species and variants are lacking. In this explorative study we genotyped 19 Fasciola isolates obtained by opportunistic sampling in the Upper East and Upper West Regions of Ghana. All isolates were identified as F. gigantica based on a partial sequence of the 28S rRNA (548 bp) gene. In addition, the complete mtDNA nad1 (903 bp) gene was employed to infer intraspecific microvariation among isolates. Six nad1 haplotypes were identified that clustered into two West African haplogroups when compared with previous records from Nigeria. These preliminary data suggest that fascioliasis in Ghana is (at least) mainly caused by F. gigantica, and that transmission may be principally autochthonous. However, the small number of isolates prevents firm conclusions, and this study is intended to stimulate molecular surveys on this neglected disease in a neglected region.

Impact of Human Activities on Fasciolosis Transmission

Fasciolosis is a worldwide disease caused by the liver fluke Fasciola spp. This food- and water-borne disease is a major public health and veterinary issue. It is currently (re)emerging in several regions mainly due to the rapid evolution of human activities. This article reviews the current knowledge of the impact of irrigation-system management, livestock management, and human diet and hygiene habits on the emergence of fasciolosis. We also identify the gaps in this knowledge and the possible solutions for limiting these impacts. Integrated control seems to be the most effective solution for controlling fasciolosis, because it enables monitoring, prevention, and rapid action in case of the (re)emergence of the disease.

Epidemiological and ultrasonographic investigation of bovine fascioliasis in smallholder production system in Eastern Nile Delta of Egypt

Regular updating of our knowledge on the epidemiological determinants of bovine fascioliasis is necessary to increase the awareness of the disease's significance and subsequently, improve the control measures. The objectives of this study were (1) to estimate the prevalence of bovine fascioliasis, and identify the association of epidemiological characteristics under traditional householders' production systems, (2) to describe the association between the clinical picture, Fasciola spp. egg count and hepatobiliary ultrasonography findings. In total, 270 faecal samples were examined microscopically for the presence or absence of Fasciola spp. egg, using the sedimentation-flotation method. Copro-positive animals were subjected to ultrasonographic examination. Overall prevalence of copro-positive animals was 27.4% (22.4-33.0%, 95% CI). The final multivariate analysis showed that there was a significant association between fascioliasis and animal species (P < 0.03), and administration of anthelmintic (P < 0.0001). Cattle have a less chance of being positive to Fasciola spp. by 0.55 (95% CI: 0.30 - 0.99) compared to water buffaloes. Administration of anthelmintic to animals on a regular basis decreased the risk of copro-positivity to Fasciola spp by 0.17 (95% CI: 0.07 - 0.36) compared to animals received anthelmintic on an irregular basis. Infected animals having different Fasciola spp. egg burden revealed different clinical symptoms associated with hepatobiliary changes on ultrasonographic examination ranged from normal hepatic parenchyma and bile system in low faecal egg load to hyperechogenic hepatic parenchyma, hyperechogenic with distal shadowing bile duct, and distended gallbladder in high faecal egg load of Fasciola spp. In conclusion, the prevalence of bovine fascioliasis is high under the traditional household's production system. Regular administration of anthelmintic significantly reduces the animal's chance of being copro-positive to Fasciola spp. Ultrasound poses a valuable prognostic technique for assessment of bovine fascioliasis.

Fasciola hepatica infections in cattle and the freshwater snail Galba truncatula from Dakhla Oasis, Egypt

Infection by Fasciola species was investigated in seven districts of Dakhla Oasis, Egypt, through abattoir inspection of cattle livers for adult worms and sedimentation of faecal samples from local cattle to detect Fasciola eggs. In addition, lymnaeid snails collected from the study area were examined microscopically for developmental stages of Fasciola spp. Abattoir inspection revealed that 51 out of 458 cattle livers (11.1%) contained adult flukes, which were identified morphologically as Fasciola hepatica. Examination of the cattle faecal samples revealed that 142 out of 503 (28.2%) contained Fasciola eggs. The collected snails, identified as Galba truncatula and Radix natalensis, showed larval stages of Fasciola in 71 out of 731 (9.7%) G. truncatula, while R. natalensis showed no infection. Specific duplex polymerase chain reaction (PCR) targeting the mitochondrial cox1 gene of F. hepatica and Fasciola gigantica was carried out on DNA extracted from pooled infected snails and adult worms. The F. hepatica size amplicon (1031 bp) was obtained from both the infected G. truncatula and the adult worms isolated from cattle livers from different districts. The amplicon sequences were identical to the published sequences of F. hepatica mitochondrial cox1 gene. In conclusion, the zoonotic importance of Fasciola infection and appropriate hygienic measures must be taken into consideration in Dakhla Oasis, Egypt.

Identity of Fasciola spp. in sheep in Egypt

Background

In Egypt, liver flukes, Fasciola spp. (Digenea: Fasciolidae), have a serious impact on the farming industry and public health. Both Fasciola hepatica and Fasciola gigantica are known to occur in cattle, providing the opportunity for genetic recombination. Little is known on the identity and genetic variability of Fasciola populations in sheep.

Methods

This study was performed to determine the prevalence of liver flukes in sheep in Menofia Province as a representative area of the delta region in Egypt, as measured by postmortem examination of slaughtered animals at three abattoirs. The identity and genetic variability of Fasciola spp. in slaughtered animals were determined by PCR-sequence analysis of the nuclear ribosomal internal transcribed spacer 1 (ITS1) and the mitochondrial NADH dehydrogenase subunit 1 (nad1) genes.

Results

Physical inspection of the liver indicated that 302 of 2058 (14.7%) slaughtered sheep were infected with Fasciola spp. Sequence analysis of the ITS1 and nad1 genes of liver flukes from 17 animals revealed that 11 animals were infected with F. hepatica, four with F. gigantica, and two with both species. Seventy eight of 103 flukes genetically characterized from these animals were F. hepatica, 23 were F. gigantica, and two had ITS1 sequences identical to F. hepatica but nad1 sequences identical to F. gigantica. nad1 sequences of Egyptian isolates of F. gigantica showed pronounced differences from those in the GenBank database. Egyptian F. gigantica haplotypes formed haplogroup D, which clustered in a sister clade with haplogroups A, B and C circulating in Asia, indicating the existence of geographic isolation in the species.

Conclusions

Both F. hepatica and F. gigantica are prevalent in sheep in Egypt and an introgressed form of the two occurs as the result of genetic recombination. In addition, a geographically isolated F. gigantica population is present in the country. The importance of these observations in epidemiology of fascioliasis needs to be examined in future studies.

CIAS detection of Fasciola hepatica/F. gigantica intermediate forms in bovines from Bangladesh

Fascioliasis is an important food-borne parasitic zoonosis caused by two trematode species, Fasciola hepatica and Fasciola gigantica. The characterisation and differentiation of Fasciola populations is crucial to control the disease, given the different transmission, epidemiology and pathology characteristics of the two species. Lineal biometric features of adult liver flukes infecting livestock have been studied to characterise and discriminate fasciolids from Bangladesh. An accurate analysis was conducted to phenotypically discriminate between fasciolids from naturally infected bovines (cattle, buffaloes) throughout the country. Morphometric analyses were made with a computer image analysis system (CIAS) applied on the basis of standardised measurements and the logistic model of the body growth and development of fasciolids in the different host groups. Since it is the first ever comprehensive study of this kind undertaken in Bangladesh, the results are compared to pure fasciolid populations of F. hepatica from the European Mediterranean area and F. gigantica from Burkina Faso, geographical areas where both species do not co-exist. Principal component analysis showed that the biometric characteristics of fasciolids from Bangladesh are situated between F. hepatica and F. gigantica standard populations, indicating the presence of phenotypes of intermediate forms in Bangladesh. These results are analysed by considering the present emergence of animal fascioliasis, the local lymnaeid fauna, the impact of climate change, and the risk of human infection in the country.