Morphology and histology of the adult Paramphistomum gracile Fischoeder, 1901

Tegumental surface change in Paramphistomum epiclitum caused by Bombax ceiba flowers and black pepper seed extract

Rumen flukes, parasites of the superfamily Paramphistomoidea, are found in cattle rumen. Heavy infections can cause symptoms such as diarrhea, weight loss, and poor body condition, resulting in a decrease in milk and meat production. This study compares the tegumental surface change of Paramphistomum epiclitum as a response to ethanolic extracts of Bombax ceiba flowers and black pepper seeds. Adult flukes were subjected to various concentrations of crude extracts, including 12.5, 25, 50, 100, and 200 μg/mL for 12, 18, and 24 h incubation. Scanning electron microscopy (SEM) exhibited that the ethanolic extracts of both Bombax ceiba flowers and black pepper seeds caused tegumental surface changes in adult P. epiclitum. Based on the results, Bombax ceiba flower extract has anthelmintic activity, compared with black pepper seed extract, towards adult P. epiclitum due to the deformation of the tegument at lower concentrations than black pepper extract.

Integrative Taxonomy of Prosogonotrema bilabiatum Vigueras, 1940 (Digenea: Sclerodistomidae): A Parasite in Atlantic Spadefish Chaetodipterus faber (Broussonet, 1782) (Acanthuriformes: Ephippidae) from Brazil

OBJECTIVES

The present work aims to expand the knowledge of the digenean species Prosogonotrema bilabiatum (Sclerodistomidae), a parasite of Chaetodipterus faber (Acanthuriformes) from Brazil, with an integrative taxonomic approach, using light microscopy, scanning electron microscopy, histology, and molecular biology.

METHODS

Forty-one digenean specimens were stained with hydrochloric carmine for morphological studies. Eleven parasites were dehydrated through a graded ethanol series, critical point dried with carbon dioxide, and coated with gold for scanning electron microscopy analysis. Four specimens were processed following histological routine and stained with hematoxylin and eosin and Gomori trichrome. DNA extracted was amplified using 28S partial primer D1-D3. Maximum likelihood and Bayesian inference were performed for phylogenetic analysis.

RESULTS

Morphometric and morphological data of the specimens studied ranged in accordance as observed in previous descriptions of the species. Observations from scanning electron microscopy and histology corroborated with those observed in stained whole mounts. Molecular analysis showed that specimens of P. bilabiatum from Brazil clustered with another two sequences of this species from different hosts and localities, with a high node support value.

CONCLUSIONS

The integrative taxonomic approach allowed to record and describe new characteristics of P. bilabiatum related to the tegument, the structure and the arrangement of its tissues. The use of molecular markers confirmed that specimens identified as P. bilabiatum from different hosts and localities are all conspecific. Further studies, mainly molecular with less conserved genetic markers, should be carried out to better understand the phylogenetic relationships of Prosogonotrema with Hemiuroidea.

A Universal Approach to Molecular Identification of Rumen Fluke Species Across Hosts, Continents, and Sample Types

Rumen fluke are parasitic trematodes that affect domestic and wild ruminants across a wide range of countries and habitats. There are 6 major genera of rumen fluke and over 70 recognized species. Accurate species identification is important to investigate the epidemiology, pathophysiology and economic impact of rumen fluke species but paramphistomes are morphologically plastic, which has resulted in numerous instances of misclassification. Here, we present a universal approach to molecular identification of rumen fluke species, including different life-cycle stages (eggs, juvenile and mature fluke) and sample preservation methods (fresh, ethanol- or formalin-fixed, and paraffin wax-embedded). Among 387 specimens from 173 animals belonging to 10 host species and originating from 14 countries on 5 continents, 10 rumen fluke species were identified based on ITS-2 intergenic spacer sequencing, including members of the genera Calicophoron, Cotylophoron, Fischeroedius, Gastrothylax, Orthocoelium, and Paramphistomum. Pairwise comparison of ITS-2 sequences from this study and GenBank showed >98.5% homology for 80% of intra-species comparisons and <98.5% homology for 97% of inter-species comparisons, suggesting that some sequence data may have been entered into public repositories with incorrect species attribution based on morphological analysis. We propose that ITS-2 sequencing could be used as a universal tool for rumen fluke identification across host and parasite species from diverse technical and geographical origins and form the basis of an international reference database for accurate species identification.

The anthelmintic potentials of medicinal plant extracts and an isolated compound (rutin, C27H30O16) from Terminalia catappa L. against Gastrothylax crumenifer

Paramphistomosis is a pathogenic disease that occurs frequently in tropical and subtropical countries including Thailand. This disease is affected in the parasites causing severe gastrointestinal disorders and death in infected animals. In the present study, we examined the anthelmintic efficacy of albendazole (ABZ) and crude plant extracts from barks of Bombax ceiba L., Diospyros rhodocalyx Kurz. and Vitex glabrata R.Br., and leaves of Terminalia catappa L. and Cassia alata L. against Gastrothylax crumenifer. The hightest anthelmintic activity on the parasites after 24 h incubation was observed in the n-butanol extract of T. catappa leaf. In this study, fractionation bioassay of n-butanol extract of T. catappa leaf was conducted to both separation and discrimination of rutin served as a new efficient compound (LC₅₀ = 28.96; LC₉₀ = 88.75 μg/mL) against G. crumenifer. This compound was confirmed by ¹H nuclear magnetic resonance (¹H NMR), ¹³C NMR, infrared (IR) and ultraviolet (UV) spectra as well as mass spectra data. The rutin-treated parasites with all dosages showed swift decrease of the motility and the relative motility (RM) and survival index (SI) were decreased obviously from 3 h until flukes were killed after 12 h of incubation. When observed with light microscopy, the parasites showed the earliest change in a limited region of the tegument. When observed by scanning electron microscopy, the parasites' tegument exhibited similar sequences of surface changes after treatments with rutin and ABZ, but less severity in ABZ treatment. The sequences of changes comprised swelling of folds and ridges, formation of blebbing, rupturing of blebs, erosions, lesions and the tegument demolition. Hence, rutin could be considered as the potential anthelmintic agent for treatment of paramphistomosis.

Rumen fluke, Fischoederius elongatus (Trematoda: Gastrothylacidae): Preliminary investigation of suitable conditions for egg hatching

Various temperatures may have different effects on the distribution of paramphistomes that cause amphistomosis in cattle, including Fischoederius elongatus. Therefore, this study aimed to investigate the effects of different temperature treatments on F. elongatus hatching, with specific identification using morphological, histological, and phylogenetic analysis. All specimens were collected from two buffalo (Bubalus bubalis) rumens in a slaughterhouse in Pathum Thani province, Thailand. F. elongatus adults were kept in phosphate buffered saline solution for egg collection. The egg specimens were incubated in tap water under four different temperature conditions: 4 °C, room temperature, 35 °C, and 55 °C. For 31 days, egg specimens of approximately 50 eggs per observation were randomly classified into three stages (undeveloped, developing (or pre-hatching), and hatched). To test the change of temperature, cold water was used for thermal shocking the egg specimens. The results indicated that rates of egg development and hatching were highest at 35 °C and significantly higher than in the other treatments (P < 0.001). In addition, statistical investigation of pre-thermal shock results also suggesting that 35 ºC may be a suitable condition for hatching F. elongatus eggs and could enhance the developing and hatching by longer periods of incubation for more than 26 days. Even changing the temperature could affect development and hatching but initial environment temperature remains an important factor. These data could be used for efficient epidemiological prediction of F. elongatus and applied in livestock management.

Dry preservation of Toxocara vitulorum by plastination technique

Background and Aim:

The most widely adopted technique to preserve the gross specimen of the parasite is immersions and storage in liquid preservatives. The present study aimed to describe the dry method of the preservation of Toxocaravitulorum using plastination technique.

Materials and Methods:

Acetone dehydrated parasites were incubated at −20°C for 1 month in five different plastination solutions, prepared by mixing melamine and turpentine oil with clove oil (MTCl)/chloroform (MTC)/isopropanol (MTI)/benzene (MTB)/xylene (MTX) in 1:1:1 ratio to infiltrate the polymer. Technical personnel was asked to assign weekly score for dryness, stickiness, shrinkage, glossiness, flexibility, and odor of the prepared model on a 5-point scale.

Results:

Overall, the plastinated parasites were dry, non-sticky, glossy, odorless, chemical-free, harmless, to some extent flexible, with detectable morphological structure including natural form but lost their natural color, and cuticle became translucent. A varying level of shrinkage was noted in all types of plastinated model, but it was least in MTCl model. One month post-plastination, the mean evaluation score for glossiness was maximum in the parasite plastinated in MTCl solution (4.50±0.17), followed by MTC (3.72±0.32), MTX (3.56±0.38), MTB (2.83±0.37), and MTI (2.31±0.33). Likewise, for flexibility, the score was maximum in the parasite plastinated in MTCl solution (4.36±0.16), followed by MTB (3.11±0.14), MTC (2.94±0.41), MTX (2.75±0.41), and MTI (1.97±0.28). The degree of dryness, stickiness, and odor of the prepared model varies non-significantly (p>0.05) with the polymer mixtures. Maximum shrinkage percentage in terms of length and width was 4.24% and 50%, respectively, in the parasites plastinated in MTB solution. Shrinkage percentage was minimal (1.81% in length and 25% in width) in the MTCl plastinated parasites. Shrinkage percentage in terms of dimension was statistically non-significant among the different polymer solutions. Plastinated models withstand the process of microbial decomposition. There were 5 and 11 odd points in favor of plastination and formalin preservation technique, respectively.

Conclusion:

The prepared T. vitulorum model in MTCl can be used as an adjunct to the parasite preserve in 10% formalin solution. The plastination technique can be used as an alternative method of liquid preservation.

The Anthelmintic Effects of Medicinal Plant Extracts Against Paramphistome Parasites, Carmyerius spatiosus

INTRODUCTION

Paramphistomosis is a disease caused by the rumen flukes which cause an acute gastroenteritis and anemia with high mortality particularly in young ruminants.

MATERIALS AND METHODS

In this study, we have investigated the anthelmintic effect of medicinal plant extracts from leaves and heartwoods of Cassia siamea L., roots of Plumbago zeylanica L. and Plumbago indica L., and leaves of Terminalia catappa L. against Carmyerius spatiosus.

RESULTS

The highest anthelminthic effect on the flukes after 24 h of exposure was found in heartwood ethyl acetate extract of C. siamea (LC₅₀ = 374.30; LC₉₀ = 749.03 ppm), root n-butanol extract of P. zeylanica (LC₅₀ = 1005.12; LC₉₀ = 2411.55 ppm), root hexane, ethyl acetate, and n-butanol extract of P. indica (LC₅₀ = 34.38, 211.34, 506.92; LC₉₀ = 64.09, 496.05, 934.86 ppm), and leaf n-butanol and water extract of T. catappa (LC₅₀ = 487.17, 470.28; LC₉₀ = 913.27, 848.23 ppm). When observed by scanning electron microscopy, the tegument showed similar sequence of morphological changes after treatments with all plant extracts, comprising of swelling of ridges and folds, blebbing, rupturing of the blebs, erosion, lesion and disruption of the tegument.

CONCLUSION

This study is the first report on the anthelmintic activity of plant extracts to C. spatiosus; therefore, these plant extracts are highly effective in the elimination of adult rumen flukes.

Plastination of macroparasites: An eco-friendly method of long-term preservation

Aim:

Preservation of macroparasites by infiltrating the polymer in the tissues can defy the inherited shortcoming of classical wet preservation method.

Materials and Methods:

Preservation was done by infiltrating the melamine alone or with xylene (MX)/chloroform (MC)/turpentine oil (MT) in 1:1 and hardener (MH) in 9:1 ratio in the tissues of the gross specimen of the animal parasites.

Results:

The plastinated models withstand the process of microbial decomposition, and remain intact in the environmental conditions. The polymer mixture resists the entry of the water molecule, and model dried just after taking out it from the water tank. Overall, the plastinated parasites were dry, non-sticky, glossy, odorless, chemical free, and harmless, to some extent flexible, with detectable morphological structure, and retain their natural form but lost their natural color. Full marks were assigned to the degree of dryness, non-stickiness, and odorlessness to the model plastinated in different solutions on a five-point scale. For flexibility, the score was 1.2, 2.2, and 2.4 for the plastinated model in melamine/MH, MX/MC, and MT solutions, respectively. The average score of glossiness was 4.6 and 5 for the specimen plastinated in melamine/MH and MX/MC/MT solutions, respectively. The degree of dryness, glossiness, stickiness, and flexibility varies non-significantly, with the polymer mixtures used.

Conclusion:

The prepared model can be used to educate the students/general mass population.

Immunodiagnosis of paramphistomosis using monoclonal antibody-based sandwich ELISA for detection of Paramphistomum gracile circulating 16 kDa antigen

In this study, we have produced a monoclonal antibody (MoAb) against 16 kDa antigen ofParamphistomum gracile(16 kDaAgPg), and developed an accurate sandwich enzyme-linked immunosorbent assay (sandwich ELISA) for the detection of circulating 16 kDaAg in the serum and fecal samples from cattle naturally infected withP. gracile. MoAb 1D10 was immobilized on a microtitre plate, and the antigen in the samples was captured and detected with biotinylated rabbit anti-16 kDaAgPg antibody. The lower detection limit of sandwich ELISA was 3·5 pg mL−1, and no cross-reaction with other parasite antigens was evaluated. The reliability of the assay was examined using the serum and fecal samples from cattle naturally infected withP. gracile, Fasciola gigantica, Moniezia benedeni, Trichurissp.,Strongyloidessp., strongylids and non-infected animals. The sandwich ELISA showed the sensitivity, specificity and accuracy at 98·33, 100 and 99·55% (serum samples), and 96·67, 100 and 99·09% (fecal samples). Therefore, this detection method is a rapid and excellent potential assay for the accurate diagnosis of paramphistomosis.

Immunodiagnostic monoclonal antibody-based sandwich ELISA of fasciolosis by detection of Fasciola gigantica circulating fatty acid binding protein

Up to now, parasitological diagnosis of fasciolosis is often unreliable and possesses low sensitivity. Hence, the detection of circulating parasite antigens is thought to be a better alternative for diagnosis of fasciolosis, as it reflects the real parasite burden. In the present study, a monoclonal antibody (MoAb) against recombinantFasciola giganticafatty acid binding protein (rFgFABP) has been produced. As well, a reliable sandwich enzyme-linked immunosorbent assay (sandwich ELISA) has been developed for the detection of circulating FABP in the sera of mice experimentally and cattle naturally infected withF. gigantica. MoAb 3A3 and biotinylated rabbit anti-recombinant FABP antibody were selected due to their high reactivities and specificities. The lower detection limit of sandwich ELISA was 5 pg mL−1, and no cross-reaction with other parasite antigens was observed. This assay could detectF. giganticainfection from day 1 post infection. In experimental mice, the sensitivity, specificity and accuracy of this assay were 93·3, 100 and 98·2%, while in natural cattle they were 96·7, 100 and 99·1%. Hence, this sandwich ELISA method showed high efficiencies and precisions for diagnosis of fasciolosis byF. gigantica.

The complete mitochondrial genome of Gastrothylax crumenifer (Gastrothylacidae, Trematoda) and comparative analyses with selected trematodes

In the present study, we sequenced and analyzed the mitochondrial (mt) genome of Gastrothylax crumenifer and compared it with other selected trematodes. The full mt genome of G. crumenifer was amplified, sequenced, assembled, analyzed and then subjected to phylogenetic analysis. The complete mt genome of G. crumenifer is 14,801 bp in length and contains two rRNA genes, two non-coding regions (LNR and SNR), 12 protein-coding genes, and 22 transfer RNA genes. The gene organization of the G. crumenifer mt genome is the same as that of other trematodes, except for Schistosoma haematobium and Schistosoma spindale. All the genes are transcribed in the same direction and rich in "A + T", which is in accordance with other trematodes, such as Fasciola hepatica, Paramphistomum cervi, and Fischoederius elongatus. Phylogenetic analysis using concatenated amino acid sequences of the 12 protein-coding genes showed that G. crumenifer is closely related to F. elongatus. The availability of mt genome sequence of G. crumenifer can provide useful DNA markers for studying the molecular epidemiology and population genetics of this parasite and other paramphistomes.

leaves against the ruminant gut parasite, Fischoederius cobboldi

Presently, no effective anthelmintic drugs have been used to treat and control paramphistomosis, a severe disease of ruminants. In this study, we have investigated thein vitroanthelmintic effect of the leaves ofTerminalia catappaL. crude extract (TcCE) and albendazole (ABZ) on adultFischoederius cobboldiafter incubating the flukes in RPMI-1640 medium containing the TcCE at various doses and times. The TcCE-treated flukes at all dosages exhibited rapid decrease of motility, and the relative motility (RM) values were decreased sharply from start to 3 h. Worms were killed after 6 and 12 h of treatment with 1000, 1500 and 2000µg mL−1as well as 500µg mL−1of TcCE, respectively. By light microscopy examination, the flukes exhibited the earliest alteration in a limited area of the tegument. At scanning electron microscopy level, the flukes’ tegument showed similar sequence of morphological alterations after treatment with ABZ and TcCE that consisted of swelling of ridges and folds, followed by blebbing and rupturing of the blebs, leading to the erosion, lesion and disruption of the tegument. Hence,in vivostudies should be performed to examine whether the TcCE may serve as a powerful anthelmintic drug for treatment of paramphistomosis.

Experimental Investigation on the Morphology and Adhesion Mechanism of Leech Posterior Suckers

The posterior sucker of a leech represents a fascinating natural system that allows the leech to adhere to different terrains and substrates. However, the mechanism of adhesion and desorption has not yet to be elucidated. In order to better understand how the adhesion is performed, we analyzed the surface structure, adsorption movements, the muscles’ distribution, physical characteristics, and the adsorption force of the leech posterior suckers by experimental investigation. Three conclusions can be drawn based on the obtained experimental results. First, the adhesion by the posterior sucker is wet adhesion, because the surface of the posterior sucker is smooth and the sealing can only be achieved on wet surfaces. Second, the deformation texture, consisting of soft collagen tissues and highly ductile epidermal tissues, plays a key role in adhering to rough surfaces. Finally, the adhesion and desorption is achieved by the synergetic operation of six muscle fibers working in different directions. Concrete saying, directional deformation of the collagen/epithermal interface driven by spatially-distributed muscle fibers facilitates the excretion of fluids in the sucker venter, thus allowing liquid sealing. Furthermore, we found that the adhesion strength is directly related to the size of the contact surface which is generated and affected by the sucker deformation. Such an underlying physical mechanism offers potential cues for developing innovative bio-inspired artificial adhesion systems.

Molecular analysis of selected paramphistome isolates from cattle in southern Africa

Paramphistomes are parasites of domestic and wild ruminants, the effects of which in animal health remain underestimated. Very few studies in Africa have been done using molecular techniques to resolve situations associated with taxonomical groupings and epidemiology of these parasites. In this study, the genetic variability of nine representative paramphistome isolates collected from southern African countries, namely Botswana, South Africa, Zambia and Zimbabwe, was assessed using both morphological and internal transcribed spacer 2 (ITS2) rDNA sequence data. Morphological characterization and identification were carried out using median sagittal sections of the paramphistomes. DNA of the individual paramphistomes was isolated, the ITS2 rDNA was amplified, purified and sequenced. The sequences were submitted to GenBank, which assigned them the following accession numbers: KP639631, KP639630, KP639632, KP639633, KP639634, KP639635, KP639636, KP639637 and KP639638. These sequences were used for phylogenetic analysis using MEGA 6. Morphological characterization revealed three species of paramphistomes belonging to three different sub-families: one Stephanopharynx compactus isolate, a member of the Stephanopharyngidae sub-family; one Carmyerius dollfusi isolate, a member of the Gastrothylacidae sub-family; and seven Calicophoron microbothrium isolates belonging to the Paramphistomidae sub-family. ITS2 sequence analysis using BlastN results indicated that this is the first report of S. compactus (KP639630) and C. dollfusi (KP639636). Phylogenetic reconstruction of the paramphistome isolates revealed three separate clades representing the three species. However, the clade with all the C. microbothrium isolates was the only one that was supported by a higher bootstrap value of 92%, although there was no differentiation of the isolates according to geographical locations. The low divergence values on the ITS2 sequences of the C. microbothrium isolates indicate that ITS rDNA sequences can be used as a molecular tool to infer knowledge for resolving taxonomic groupings.

Surface topography and ultrastructural architecture of the tegument of adult Carmyerius spatiosus Brandes, 1898

Adult Carmyerius spatiosus or stomach fluke has an elongate, cylindrical-shaped, straight to slightly curved body, with conical anterior end and truncated posterior end. The worm measures about 8.7-11.2mm in body length and 2.3-3.0mm in body width across the mid-section. When observed by SEM, the tegumental surface in all part of the body appears highly corrugated with ridges and furrows, and having no spines. The ventral surface has more complex corrugation than those of the dorsal surface. Both anterior and posterior suckers have thick edges covered with transverse folds and appear spineless. The genital pore is located at the anterior part of the body. There are two types of sensory papillae on the surface: type 1 is bulbous in shape with nipple-like tips; type 2 has a similar shape with short cilia on the tip. The dorsal surface exhibits similar surface features, but papillae appear less numerous and are smaller. When observed by TEM, the tegument is divided into four layers. The first layer includes the ridges and furrows which are covered by a trilaminate membrane underlined by a dense lamina and coated externally with the glycocalyx. The second layer of the tegument is a narrow region of cytoplasm that contains high concentrations of ovoid electron lucent tegumental granules (TG1), and disc-shaped electron dense tegumental granules (TG2) as well as lysosomes. TG1 close to the surface invariably exocytose their content into bottoms of the ridges, while some TG2 are fused and have their membrane joined up with the surface membrane. The third layer is the widest middle area of the tegument which contains numerous and evenly distributed mitochondria. Both TG1 and TG2 granules are present but in much fewer number than in the first and second layers. The fourth layer is the innermost zone that rests on and couples with a thick basal lamina. The cytoplasm in this layer is loosely packed and contains numerous infoldings of the basal plasma membrane with closely associated mitochondria. It also contains fairly large numbers of TG1 and TG2 granules which are produced and transported to the tegument by one type of tegumental cells lying in rows underneath the muscular layers.

Molecular characterization of Gastrothylax crumenifer (Platyhelminthes: Gastrothylacidae) from goats in the western part of India by LSU of nuclear ribosomal DNA

The rumen parasite, Gastrothylax crumenifer (Platyhelminthes: Gastrothylacidae), is a highly pathogenic trematode parasite of goat (Capra hircus). It sucks blood that causes acute disease like anemia, and severe economic losses occur due to morbidity and mortality of the ruminant infected by these worms. The study of these rumen paramphistomes, their infection, and public health importance remains unclear in India especially in the western part of state Uttar Pradesh (U.P.), Meerut, India, where the goat meat consumption is very high. This paper provides the molecular characterization of G. crumenifer recovered from the rumen of Capra hircus from Meerut, U.P., India by the partial sequence of 28S rDNA. Nucleotide sequence similarity searching on BLAST of 28S rDNA from parasites showed the highest identity with those of G. crumenifer from the same host Capra hircus. This is the first report of molecular identification of G. crumenifer from this part of India.

Production and characterization of a monoclonal antibody against recombinant cathepsin L1 of Fasciola gigantica

Monoclonal antibodies (MoAbs) against a recombinant cathepsin L1 of Fasciola gigantica (rFgCatL1) were produced in vitro by fusion of BALB/c mice spleen cells immunized with rFgCatL1 and mouse myeloma cells. Reactivity and specificity of these MoAbs were evaluated by indirect ELISA and immunoblotting techniques. Seven MoAb clones were selected from the stable hybridoma clones, namely 1E10, 1F5, 3D11, 4B10, 4D3, 4E3 and 5E7. Clones 1E10, 1F5 and 3D11 were IgM, whereas clones 4B10, 4D3, 4E3 and 5E7 were IgG1. All MoAbs had kappa light chain isotypes. All MoAbs reacted with rCatL1 at molecular weight (MW) 30kDa and with the native CatL1 at MW 27kDa in whole body (WB) extracts of metacercariae (Met), newly excysted juveniles (NEJ), 1, 3, 5-week-old juveniles (Ju), adult WB and adult excretory-secretory (ES) fractions, but not with adult tegumental antigens (TA). All of these MoAbs showed no cross-reactions with antigens of other parasites commonly found in ruminants and human, including Paramphistomum cervi, Eurytrema pancreaticum, Gigantocotyle explanatum, Schistosoma spindale, Schistosoma mansoni, Moniezia benedeni, Avitellina centripunctata, Trichuris sp., Haemonchus placei and Setaria labiato-papillosa. Localization of CatL1 in each developmental stages of F. gigantica by immunoperoxidase technique, using these MoAbs as probes, indicated that CatL1 was present at high concentration in the caecal epithelium and caecal lumen of metacercariae, NEJ, 1, 3, 5-week-old juveniles and adult fluke. This finding indicated that CatL1 is a copiously expressed parasite protein that is released into the ES, thus CatL1 and its MoAb could be a good candidate for immunodiagnosis of fasciolosis in ruminant and human.