Multi-scale habitat modeling framework for predicting the potential distribution of sheep gastrointestinal nematodes across Iran's three distinct climatic zones: a MaxEnt machine-learning algorithm.

Ecological niche models (ENMs) serve as valuable tools in assessing the potential species distribution, identifying crucial habitat components for species associations, and facilitating conservation efforts. The current study aimed to investigate the gastrointestinal nematodes (GINs) infection in sheep, predict and analyze their ecological niches and ranges, and identify the key bioclimatic variables influencing their distribution across three distinct climatic regions in Iran. In a cross-sectional study, a total of 2140 fecal samples were collected from semi-arid (n = 800), arid (n = 500), and humid-subtropical (n = 840) climates in East Azerbaijan, Kerman, and Guilan provinces, respectively. The flotation method was employed to assess stool samples, whereby the fecal egg count (the number of parasite eggs per gram [EPG]) was ascertained for each individual specimen. Employing a presence-only approach, the multi-scale maximum entropy (MaxEnt) method was used to model GINs' habitat suitability using 93 selected points/locations. The findings revealed that Guilan (34.2%) and East Azerbaijan (19.62%) exhibited the utmost proportion of Strongyle-type eggs. East Azerbaijan province also displayed the highest proportion of Marshallagia and Nematodirus, respectively (approximately 40% and 27%), followed by Guilan and Kerman provinces, while Kerman province had the highest proportion of Trichuris (approximately 15%). Ecological niche modeling revealed that the precipitation of the driest quarter (Bio17) exerted the most significant influence on Marshallagia, Nematodirus, Trichuris, and ُSُُُtrongyle-type eggs' presence in East Azerbaijan and Kerman provinces. For Guilan province, the most influential factor defining habitat suitability for Strongyle-type eggs, Marshallagia, and Nematodirus was increasing slope. Additionally, the distribution of Trichuris was most affected by the variable Bio2 in Guilan province. The study highlights the response of GINs to climate drivers in highly suitable regions, providing insights into ecologically favorable areas for GINs. In conclusion, this study provides a better understanding of GINs and the environmental factors influencing their transmission dynamics.

Diversity and burden of helminthiasis in wild ruminants in Iran.

This paper aimed to investigate the diversity and burden of helminthiasis in Ovis orientalis (n = 26), Capra aegagrus (n = 29) and Gazella subgutturosa (n = 24) grazed in 37 National Parks in 9 provinces of Iran. The organs and body cavities infected by helminths included gastrointestinal tract, peritoneal cavity, heart, liver and lungs. The contents were extracted and washed under running water and intestinal and lung-isolated nematodes were cleared in lactophenol and subsequently fixed, and cestodes were stained with alum carmine and mounted en face in Berlese's fluid under slight pressure between a microscopic slide and cover slip. The helminth species identified in this study include: intestinal nematodes (Marshallagia marshalli, Teladorsagia circumcincta, Ostertagia ostertagi, Nematodirus oiratianus, Nematodirella longispiculata, Skrjabinema ovis, Trichuris ovis, Trichuris discolor, Parabronema skrjabini), lungworms (Protostrongylus rufescens, Cystocaulus ocreatus), adult cestodes (Moniezia expansa, Helicometra giardi, Avitellina centripunctata, Stilesia globipunctata) and metacestodes (Cysticercus spp., hydatid cyst, Cysticercus tenuicollis). The proportion of the different helminth species ranged from low to moderate (3.45-46.15%) and the intensity of helminth isolation from the different ruminants ranged between 2 and 20. All the taxa identified in our study have been reported in wild animal species around the world. The presence of Cysticercus spp. with cardiac involvement in G. subgutturosa and all helminths of C. aegagrus was reported for the first time in Iran. A significant reduction was observed in worm burden, compared with previous studies in Iran, indicating changes in wildlife host-parasite systems, which can be linked to many reasons including climate changes, public health policies (e.g., strategic anthelmintic use in domestic ruminants), anthropogenic factors and environmental changes (e.g., urbanization or agricultural expansion, physical barriers), as well as vegetation growth and host availability.

A faunistic survey of snails and their infection with digenean trematode cercariae in Bandar-e Anzali at the littoral of the Caspian Sea.

Trematodes are known as a diverse group of endogenous parasites, which snails as their intermediate hosts can dramatically affect parasite transmission dynamics. Snails play a key role in life cycles of digenean trematode. However, there has not been much faunistic surveys in terms of snails' distribution in Iran. The current study was aimed to identify snail's fauna and their current geographic distribution in four regions of Guilan province, Iran. Several species of snails (land and freshwater snails) were obtained from 4 different areas (2018-2019), and then samples were separately transferred to the laboratory. Diagnosis of snails was then performed according to morphometric characteristics including dextral or sinistral shell, shape, color and size of shell. Moreover, radula was stained and then photographed under microscopic examination. Furthermore, 25% of any species were tested for cercarial infection. In total, 2082 snails belonging to 12 species were identified based on the morphological characteristics. Land snails were identified to be Helicella sp. (46.4%), Helix aspersa (34.1%), Helicopsis sp. (8%), Pomatia sp. (6.7%) and Oxyloma elegans (4.8%). Moreover, freshwater snails were Physa acuta (30.6%), Lymnaea auricularia (25.8%), Lymnaea gedrosiana (18.7%), Lymnaea palustris (8.9%), Lymnaea truncatula (8.1%), Planorbis sp. (6.4%) and Lymnaea stagnalis (1.5%). In collected snails, Lymnaea auricularia (0.66%) and Lymnaea gedrosiana (0.45%) were the only snails harboring cercariae (Gymnocephalus cercariae). There was no statistically significant difference between the cercarial infection and snail species (P<0.05). Comprehensive field studies are highly needed for better evaluation of the snail biodiversity in the Caspian Sea region due to the particular climatic conditions and the high prevalence of trematodosis.

Predicting environmental suitability and geographical distribution of Dicrocoelium dendriticum at littoral of Caspian Sea: An ecological niche-based modeling.

Dicrocoeliasisis caused by the small liver fluke (Dicrocoelium spp.), mainly Dicrocoelium dendriticum in domestic and wild ruminants. The small liver fluke is the probable predisposing cause of economic burden. The impact of geographic and climatic factors on the incidence of dicrocoeliasis has been severely ignored in different geographical areas. Due to the lack of data regarding dicrocoeliasis in Iran, this study was aimed to investigate the prevalence and intensity of ovine and bovine Dicrocoelium infection in the coastal strip south of the Caspian Sea. Fecal samples were obtained from the cattle and sheep in three provinces of Guilan, Mazandaran and Golestan at the littoral of the Caspian Sea. All collected samples were then tested by flotation methods for determining the number of eggs per gram of feces (EPG). Moreover, we applied maximum entropy niche-based modeling (MaxEnt), coupled with remote sensing and the Geographical Information System (GIS) to visualize the spatial distribution and risk factors of Dicrocoelium dendriticum at the littoral of Caspian Sea. A total of 2688 stool samples were collected from cattle (n = 1344) and sheep (n = 1344) in coastal provinces of the Caspian Sea including Guilan (n = 1280), Mazandaran (n = 768) and Golestan (n = 640) provinces. Based on the data presented here, the highest rate of infection was observed in Guilan and Mazandaran provinces. The results revealed the prevalence rates of 36.72% and 6.09% for sheep and cattle in Guilan province, respectively. This rate was 22.4% for sheep and 3.91% for cattle in Mazandaran province. However, the rate of sheep infection was 90% in some point locations. Dicrocoelium infection was found to be significantly different between three provinces in sheep (P < 0.00001, Chi = 111.633). Our findings exhibited a high reliability of the MaxEnt model, and area under the curve (AUC) values of the training and test data sets were determined to be 0.852 and 0.818, respectively. Jackknife analysis showed the relative variable contribution to the model performance, where four variables were found as key influential factors that highly affected the habitat suitability of the presence of the lancet fluke including the precipitation of driest quarter (Bio17), altitude, temperature seasonality (Bio4), and precipitation of driest month (Bio14). The findings of this study demonstrated a high presence rate of Dicrocoelium infection at the littoral of Caspian Sea, Iran. Moreover, climatic variables can be considered as important predictive factors affecting the distribution of infection in the studied areas. Further studies based on the findings of the GIS are also very important in the country for planning control programs.

Ecological niche modeling for predicting the habitat suitability of fascioliasis based on maximum entropy model in southern Caspian Sea littoral, Iran.

The present study aimed to determine the number of cases of animal fascioliasis per district in the southern littoral of Caspian Sea and to model suitable ecological niches for Fasciola infection in the region. Stool samples (n = 2688) were collected from cattle and sheep in Guilan, Mazandaran and Golestan provinces. The samples were tested using flotation method, and the number of parasite eggs per gram (EPG) of feces was recorded for each sample. Occurrence-only data of Fasciola were collected from the field. A total of 96 points/locations were used to model the ecological niche of Fasciola in maximum entropy (MaxEnt) and geographical information system (GIS). The spatial layers were compiled from 23 bioclimatic and biophysical variables for modeling analysis. Jackknife analysis was used to determine the relative importance of all variables in the model. In the present study, the proportion of fascioliasis in both hosts was highest in Guilan province (sheep: 12.34%, cattle: 15.16%), followed by Mazandaran (sheep: 7.3%, cattle: 6.25%) and Golestan (sheep: 0%, cattle: 0.94%) provinces. The Area Under Curve (AUC) value of the model was 0.909, indicating a good predictive power of the model. Our modeling results indicate that four variables, which were markedly incorporated into the model, are the major predictors of the presence probability of Fasciola spp. in the region: Bio17 (Precipitation of driest quarter; 45.5%), Bio14 (Precipitation of driest month; 24.8%), aspect (9%), and altitude (7.2%). The data presented herein show expansion of the potential high-risk areas of fascioliasis in the northern part of Iran, located at the southern littoral of Caspian Sea, especially in Guilan province. However, the extent of the predicted risk zones varied between the different areas of the region and within provinces, such that at the present, many parts of Golestan province are less environmentally suitable for Fasciola distribution than other areas in the region.

Design and synthesis of a new peptide derived from Fasciola gigantica cathepsin L1 with potential application in serodiagnosis of fascioliasis.

Fascioliasis is a global parasitic disease that affects domestic animals and causes considerable economic losses in the process of domestic animal breeding in endemic regions. The cause of the disease involves a liver trematode of the genus Fasciola, which secretes materials into a host's body (mainly proteins) in order to protect it from the host's immune system. These materials can be involved in the migration, growth, and nutrition of the parasite. Among the expressive proteins of Fasciola, proteases have been introduced as the appropriate targets for diagnosis, treatment, and vaccination against parasites. Cathepsin L (CL) is a member of cysteine proteases; it is widely expressed in the Fasciola species. The aim of this study was to evaluate two synthetic peptides from F. gigantica CL1 for improving serological diagnosis of the Fasciola infection. Therefore, the potential diagnostic value of the surface epitopes of CL1 was assessed using ELISA. In the current study, bioinformatics tools were applied to select two appropriate epitopes of Fasciola Cathepsin L1 as synthetic antigens. Their diagnostic values were evaluated by two methods of indirect ELISA and dot blot analysis. The findings revealed that the first peptide at a dilution ratio of 1:400 and the second peptide at a dilution ratio of 1:100 had the best results and the best concentration of antigens was introduced at 4 µg/ml. Moreover, 191 sera samples were analyzed by both peptides by using the ELISA method, including fascioliasis sera, other parasitic sera and negative sera. The sensitivity of the peptides 1-ELISA and peptide 2-ELISA for the diagnosis of the various cases was 100%. The specificity of the first peptide was 87.3% and its efficacy was determined to be 93.65%. The specificity and the efficacy of the second peptide were 79% and 89.5%, respectively. The positive predictive values of the first and second peptides were obtained to be 86.27% and 79.27% respectively, and the negative predictive values of both peptides was calculated as 100%. In conclusion, the results of this study indicated that the peptide 1 from CL1 may be used as an appropriate antigen for the diagnosis of fascioliasis if the findings are backed up by using other serodiagnostic methods for checking serological cross-reactivity linked to other parasites.

Molecular and morphological characterization of Parabronema skrjabini of sheep and goats at three different geographical zones in Iran.

Parabronema skrjabini is a spirurid nematode of the family Habronematidae that lives in the abomasum of ruminants such as sheep and goats. The purpose of this study was to investigate the molecular and morphological aspects of Parabronema skrjabini in sheep and goats in Iran. The worms were collected from these animal species from three different regions. An internal transcribed spacer 2 ribosomal DNA (ITS2-rDNA) fragment of Parabronema skrjabini was amplified by polymerase chain reaction (PCR) using a pair of specific primers (Para-Ir-R and Para-Ir-F). Morphological studies based on the body length, the frontal shield, spicules of male and egg dimensions were performed. ITS2-rDNA sequences were between 167 and 299 bp in different isolates. ITS2 homology in different isolates was between 68% and 77% compared with the sequence data in GenBank. Morphological results showed that the average length of male and female worms in sheep were 16.5 mm and 36 mm and in goats 16 mm and 35.5 mm, respectively. The average length of the small and large spicules in sheep were 657.5 µm and 304.07 µm and in goats 653.08 µm and 302.66 µm, respectively. To our knowledge, this is the first study in the world exploring the genetic diversity of Parabronema in sheep and goats. Add this sentence in discussion: the low ITS2-rDNA identity in different isolates from Iran as compared to the reference sequence in GenBank (68-77%) raise questions regarding the species identity of the parasites isolated in Iran.

Genotype and Phenotype of Echinococcus granulosus Derived from Wild Sheep (Ovis orientalis) in Iran.

The aim of the present study is to determine the characteristics of genotype and phenotype of Echinococcus granulosus derived from wild sheep and to compare them with the strains of E. granulosus sensu stricto (sheep-dog) and E. granulosus camel strain (camel-dog) in Iran. In Khojir National Park, near Tehran, Iran, a fertile hydatid cyst was recently found in the liver of a dead wild sheep (Ovis orientalis). The number of protoscolices (n=6,000) proved enough for an experimental infection in a dog. The characteristics of large and small hooks of metacestode were statistically determined as the sensu stricto strain but not the camel strain (P=0.5). To determine E. granulosus genotype, 20 adult worms of this type were collected from the infected dog. The second internal transcribed spacer (ITS2) of the nuclear ribosomal DNA (rDNA) and cytochrome c oxidase 1 subunit (COX1) of the mitochondrial DNA were amplified from individual adult worm by PCR. Subsequently, the PCR product was sequenced by Sanger method. The lengths of ITS2 and COX1 sequences were 378 and 857 bp, respectively, for all the sequenced samples. The amplified DNA sequences from both ribosomal and mitochondrial genes were highly similar (99% and 98%, respectively) to that of the ovine strain in the GenBank database. The results of the present study indicate that the morpho-molecular features and characteristics of E. granulosus in the Iranian wild sheep are the same as those of the sheep-dog E. granulosus sensu stricto strain.

Phylogenetic Study of Haemonchus Species from Iran Based On Morpho-Molecular Characterization.

BACKGROUND: Haemonchosis has a negative effect on the farming industry throughout the world, especially in the tropic and sub-tropic countries. The present study was carried out to differentiate Haemonchus species from its main hosts in Iran, including sheep, goat and camel. METHODS: The identification took place based on the morphometrics of the spicules and molecular characters. Two hundred seventy adult male nematodes were collected from the abomasums of different ruminants (90 samples from each animal) at the slaughterhouses from different localities in Iran. Samples were morphologically identified according to the spicules' morphometric measurements. In the section on molecular study, 10 samples of each Haemonchus isolates were genetically examined. A simple PCR-restriction fragment length polymorphism (PCR-RFLP) assay of the second internal transcribed spacer of ribosomal DNA (ITS2-rDNA) were described to confirm the PCR results. RESULTS: PCR-RFLP profile obtained from the restriction enzyme HPa1 in H. contortus and H. longistipes indicated 1 (278 bp) and 2 (113 and 135 bp) different fragments, respectively. The morphological parameters clearly distinguish H. contortus from H. longistipes. Moreover, regarding the ITS2-rDNA, sequences of 295 bp and 314 bp were obtained from H. contortus and H. longistipes, respectively. CONCLUSION: The genotypic results are in agreement with the phenotypic findings of both species.

Improved serodiagnosis of hydatid cyst disease using gold nanoparticle labeled antigen B in naturally infected sheep.

BACKGROUND: Cystic echinococcosis caused by the metacestode of Echinococcus granulosus is a major problem in both humans and domestic animals health. Therefore, a standardized and approachable diagnostic tool (rapid tests) for the serodiagnosis of cystic echinococcosis (CE) is still needed. METHODS: In the present work, antigen B labeled with gold nanoparticles was used to detect antibodies against hydatid cyst disease. The prepared antigen B was analyzed by SDS-PAGE. Tetra chloroauric acid (HAuCl4) was used to produce colloidal gold and antigen B labeled by gold nanoparticles, then it was tested by using rabbits antisera and sera from naturally infected sheep. The labeled antigen B was evaluated using Dot-immunogold staining (Dot-IGS) method. RESULTS: Electrophoretic pattern of hydatid cyst fluid showed the quality of bands in the condensed fluid is better than crude fluid. SDS-PAGE analysis cyst fluid and antigen B revealed three specific protein bands that were detected at molecular weights of 24, 30 and 40 kDa that all are the subunits of antigen B. Evaluation of antigen B labeled by gold nanoparticles by using Dot-IGS technique showed 1/1 and 1/50 dilutions in comparison with another has the best immunoreaction. In this method, nanoparticles produced a typical purple color, when they binded to the strip at the site of immunoreaction. CONCLUSION: Therefore, using gold nanoparticles is a good candidate for detection of helminthiasis, also as selective tools of early detection, simple and cost-effective, regardless of specific skills and equipment with optimal durability.