An insulin-like signalling pathway model for Fasciola gigantica.

BACKGROUND: The insulin/insulin-like signalling (IIS) pathway is common in mammals and invertebrates, and the IIS pathway is unknown in Fasciola gigantica. In the present study, the IIS pathway was reconstructed in F. gigantica. We defined the components involved in the IIS pathway and investigated the transcription profiles of these genes for all developmental stages of F. gigantica. In addition, the presence of these components in excretory and secretory products (ESPs) was predicted via signal peptide annotation. RESULTS: The core components of the IIS pathway were detected in F. gigantica. Among these proteins, one ligand (FgILP) and one insulin-like molecule binding protein (FgIGFBP) were analysed. Interestingly, three receptors (FgIR-1/FgIR-2/FgIR-3) were detected, and a novel receptor, FgIR-3, was screened, suggesting novel functions. Fg14-3-3ζ, Fgirs, and Fgpp2a exhibited increased transcription in 42-day-old juveniles and 70-day-old juveniles, while Fgilp, Fgigfb, Fgsgk-1, Fgakt-1, Fgir-3, Fgpten, and Fgaap-1 exhibited increased transcription in metacercariae. FgILP, FgIGFBP, FgIR-2, FgIR-3, and two transcription factors (FgHSF-1 and FgSKN-1) were predicted to be present in FgESPs, indicating their exogenous roles. CONCLUSIONS: This study helps to elucidate the signal transduction pathway of IIS in F. gigantica, which will aid in understanding the interaction between flukes and hosts, as well as in understanding fluke developmental regulation, and will also lay a foundation for further characterisation of the IIS pathways of trematodes.

Bioclimatic analysis and spatial distribution of fascioliasis causative agents by assessment of Lymnaeidae snails in northwestern provinces of Iran.

BACKGROUND: Snails of the Lymnaeidae family are the intermediate hosts of Fasciola species, the causative agents of fascioliasis. The purpose of this study was to determine the prevalence of Fasciola species in lymnaeid snails and to investigate the association of geoclimatic factors and Fasciola species distribution in northwestern provinces of Iran using geographical information system (GIS) data. METHODS: A total of 2000 lymnaeid snails were collected from 33 permanent and seasonal habitats in northwestern Iran during the period from June to November 2021. After identification by standard morphological keys, they were subjected to shedding and crushing methods. Different stages of Fasciola obtained from these snails were subjected to the ITS1 polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method for species identification. The associations of weather temperature, rainfall, humidity, evaporation, air pressure, wind speed, elevation, and land cover with the distribution of Fasciola species were investigated. Geographical and statistical analysis was performed using ArcMap and SPSS software, respectively, to determine factors related to Fasciola species distribution. RESULTS: Of the 2000 snails collected, 19 were infected with Fasciola hepatica (0.09%), six with F. gigantica (0.03%), and 13 with other trematodes. Among geoclimatic and environmental factors, mean humidity, maximum humidity, and wind speed were significantly higher in areas where F. hepatica was more common than F. gigantica. The altitude of F. hepatica-prevalent areas was generally lower than F. gigantica areas. No significant relationship was observed between other investigated geoclimatic factors and the distribution of infected snails. CONCLUSIONS: The present study showed the relationship of humidity and wind speed with the distribution of snails infected with F. hepatica or F. gigantica in the northwestern regions of Iran. In contrast to F. gigantica, F. hepatica was more prevalent in low-altitude areas. Further research is recommended to elucidate the relationship between geoclimatic factors and the presence of intermediate hosts of the two Fasciola species.

Molecular and biochemical characterizations of a Fasciola gigantica retinoid X receptor-α isoform A (FgRXRα-A).

Fascioliasis is a parasitic infection in animals and humans caused by the parasitic flatworm genus Fasciola, which has two major species, F. hepatica and F. gigantica. A major concern regarding this disease is drug resistance, which is increasingly reported worldwide. Hence, the discovery of a novel drug as well as drug targets is crucially required. Therefore, this study aims to characterize the novel drug target in the adult F. gigantica. In the beginning, we hypothesized that the parasite might interact with some host molecules when it lives inside the liver parenchyma or bile ducts, specifically hormones and hormone-like molecules, through the specific receptors, primarily nuclear receptors (NRs), which are recognized as a major drug target in various diseases. The retinoid X receptor (RXR) is a member of subfamily 2 NRs that plays multitudinous roles in organisms by forming homodimers or heterodimers with other NRs. We obtained the full-length amino acid sequences of F. gigantica retinoid X receptor-alpha (FgRXRα-A) from the transcriptome of F. gigantica that existed in the NCBI database. The FgRXRα-A were computationally predicted for the basic properties, multiple aligned, phylogeny analyzed, and generated of 2D and 3D models. Moreover, FgRXRα-A was molecular cloned and expressed as a recombinant protein (rFgRXRα-A), then used for immunization for specific polyclonal antibodies. The native FgRXRα-A was detected in the parasite extracts and tissues, and the function was investigated by in vitro binding assay. The results demonstrated the conservation of FgRXRα-A to the other RXRs, especially RXRs from the trematodes. Interestingly, the native FgRXRα-A could be detected in the testes of the parasite, where the sex hormones are accumulated. Moreover, the binding assay revealed the interaction of 9-cis retinoic acid and FgRXRα-A, suggesting the function of FgRXRα-A. Our findings suggested that FgRXRα-A will be involved with the sexual reproduction of the parasite by forming heterodimers with other NRs, and it could be the potential target for further drug development of fascioliasis.

Trematode infection in ruminants and diversity of snail hosts across three agro-ecological zones in Ethiopia.

The occurrence of trematodes among ruminants and their snail vectors is a major concern across various agro-ecological regions of Ethiopia. Trematodes pose significant threats to animals, causing considerable economic losses and impacting public health. In this study, we have investigated 784 ruminant fecal samples, and 520 abattoir samples, alongside the collection and identification of snail vectors from various agro-ecological regions. Fecal examinations revealed Fasciola, Paramphistomum and Schistosoma species infected 20.5% (95% CI: 17.6, 23.8), 11.7% (95% CI: 9.6, 14.2), and 6.3% (95% CI: 4.1, 9.1) of the animals, respectively. The overall prevalence of trematodes among ruminants was 28.8% (95% CI: 25.7, 32.1%), with 6.0% (95% CI: 4.3, 7.7) showing mixed infections. Fasciola was more prevalent in Asela (26%) compared to Batu (19%) and Hawassa (11.5%), while a higher proportion of animals in Batu were infected with Paramphistomum. Schistosoma eggs were detected only in Batu (12.5%), but not in other areas. Sheep and cattle exhibited higher infection rates with Fasciola, Paramphistoma, and Schistosoma compared to goats. Significant associations were observed between trematode infections and risk factors including agro-ecology, animal species, body condition score, and deworming practices. About 20.8% and 22.7% of the slaughtered animals harbored Fasciola and Paramphistomum flukes, respectively, with a higher prevalence in Asela and Hawassa abattoirs compared to Batu abattoir. Additionally, a total of 278 snails were collected from the study areas and identified as lymnae natalensis, lymnae trancatula, Biomphalaria pffiferi, Biomphlaria sudanica, and Bulinus globosus. In conclusion, the study highlights the widespread occurrence of trematode infections, emphasizing the need for feasible control measures to mitigate their economic and public health impacts.

Cholelithiasis in a goat associated with chronic fascioliosis in Bangladesh: A case report and review of literatures.

The objective of the present study was to describe a very rare case of gallstone (cholelithiasis) in a goat associated with chronic fasciolosis. During a routine slaughterhouse-based survey, a two-and-half-year-old female Black Bengal Goat was found to be affected with severe chronic fascioliosis characterized by the massive damage in the liver. Through systemic dissection of liver, we isolated 94 adult Fasciola spp., and by PCR, we confirmed the fluke as Fasciola gigantica. The gallbladder of the goat was oedematous. On opening the gallbladder, we recovered 255 stones of variable sizes. Stones were whitish in colour and friable, and some of the fragile stones were attached to the wall of the gallbladder. To the authors' knowledge, this is the first report of the cholelithiasis in a goat associated with F. gigantica.

Intra- and interspecies variation and population dynamics of Fasciola gigantica among ruminants in Sudan.

Fasciola gigantica is a widespread parasite that causes neglected disease in livestock worldwide. Its high transmissibility and dispersion are attributed to its ability to infect intermediate snail hosts and adapt to various mammalian definitive hosts. This study investigated the variation and population dynamics of F. gigantica in cattle, sheep, and goats from three states in Sudan. Mitochondrial cytochrome c oxidase subunit I (COI) and NADH dehydrogenase subunit 1 (ND1) genes were sequenced successfully to examine intra and interspecific differences. ND1 exhibited higher diversity than COI, with 15 haplotypes and 10 haplotypes, respectively. Both genes had high haplotype diversity but low nucleotide diversity, with 21 and 11 polymorphic sites for ND1 and COI, respectively. Mismatch distribution analysis and neutrality tests revealed that F. gigantica from different host species was in a state of population expansion. Maximum likelihood phylogenetic trees and median networks revealed that F. gigantica in Sudan and other African countries had host-specific and country-specific lineages for both genes. The study also indicated that F. gigantica-infected small ruminants were evolutionarily distant, suggesting deep and historical interspecies adaptation.

Parasitic contamination of fresh vegetables and fruits sold in open-air markets in peri-urban areas of Jimma City, Oromia, Ethiopia: A community-based cross-sectional study.

BACKGROUND: Consuming contaminated raw vegetables and fruits is one of the primary means of parasite transmission to humans. Periodic monitoring of parasitic contamination in these food items is a crucial step in preventing the spread of parasitic disease in the community. This study was aimed at detecting intestinal parasitic contamination caused by consuming raw vegetables and fruits sold in three open-air markets and its associated factors in peri-urban areas of Jimma City, Oromia, Ethiopia. METHODS: A cross-sectional study was conducted on fruits and vegetables collected from three peri-urban open-aired markets (namely; Hora Gibe, Bore and Jiren markets) in peri-urban areas of Jimma City between July and September 2021. A total of 187 fresh vegetable samples and 188 fruits were collected and examined for intestinal parasite contamination. About 200g of fruit and vegetable samples were processed and examined microscopically for parasite contamination, utilizing direct wet mount and modified Zeihl-Neelson staining methods in accordance with standard protocols. A structured questionnaire was used to collect data on the socio-demographic characteristics of vendors and risk factors for fruit and vegetable contamination. All data were analyzed using SPSS version 20.0. RESULT: Of the 187 fresh vegetable samples and 188 fresh vegetable samples, 105 (56.1%) and 68/188 (36.2%) of vegetables and fruit samples, respectively, were found contaminated with one or more intestinal parasites. Remarkably, high level of contamination in fresh vegetable samples was recorded both in Carrot (Daucus carota) 63.8% (30/46) and Lettuce (Lactuca sativa) 63.1% (29/46) while Green pepper (Capsicum spp.) is the least contaminated. In fruit samples, Avokado (Persea americana) 42.6% (20/47) and Banana (Musa acuminata) 14.9% (7/47) were the most and the least commonly contaminated items respectively. The identified helminthes and protozoans were Ascaris lumbricoides, Strongyloides stercoralis, Hymenolepis nana, Entamoeba histolytica/dispar, Giardia lamblia, Cryptosporidium spp., Toxocara spp. And Fasciola spp. The most predominant parasite encountered was A. lumbricoides 46(12.3%) whereas both Toxocara spp. 12(6.9) and Fasciola spp. 2(0.5) were the least detected parasites. It is worth-mentioned that the rate of contamination in Bore market (38.15%) was higher compared with Jiren market (34.7%) and Hora Gibe market (27%). However, the rate of contamination in vegetables and fruit obtained from the three district was non-significant (p = 0.19). Contamination was more common in vegetables than fruits (AOR = 5.78, p<0.001). It was also observed that decreased parasitic contamination was significantly associated with washing the products before displaying it for selling (p < 0.001). CONCLUSION: The study has identified a high rate of raw vegetables and fruits contaminated with intestinal helminthes and protozoan. Contaminated fresh vegetables and fruits in open-aired peri-urban markets of Jimma city, Ethiopia may play a significant role in transmission of intestinal parasitic infections to humans, particularly A. lumbricoides infection. Therefore, it is urgently needed for health authorities to educate the public on the proper handling of vegetables and fruits prior to consumption.

Prevalence and risk factors of fasciolosis in a bovine population from farms in Taiping, Malaysia.

Fasciolosis is a zoonotic disease, considered an emerging neglected tropical disease threatening ruminant productivity and causing economic losses. Controlling fasciolosis is challenging due to the complex life cycle of Fasciola, which involves snail intermediate hosts. The high rainfall status in Taiping makes it an optimal region for snail abundance, which increases the opportunity to complete Fasciola's life cycle. Previous studies showed that liver condemnation caused by fasciolosis was highly prevalent in the Taiping abattoir compared to other investigated main abattoirs of Peninsular Malaysia. Therefore, the present study determined the prevalence of bovine fasciolosis and risk factors in farms from Larut and Matang (Taiping), Malaysia. Sampling was carried out from February until August 2020. In this cross-sectional study, a total of 371 fecal samples from bovines (dairy cattle, beef cattle, buffalo) were examined from 23 farms selected based on location, farmer consent, and history of anthelmintic usage. Animal's intrinsic and farm management details were recorded, and interview sessions were conducted with farmers to collect information on the potential risk factors. Individual fecal samples were examined for the presence of Fasciola egg using Flukefinder® sedimentation. There was moderate prevalence of bovine fasciolosis in Taiping (36.9%, n = 137/371). Significant risk factors (p < 0.05) were observed, which include buffalo group (OR = 9.5, 95% CI: 9.44-9.55), age of >3 years (OR = 5.5, 95% CI: 5.43-5.57), thinner animals with body condition score of 1 to 4 (OR = 1.2-14.9, 95% CI: 1.09-15.08), and larger grazing area (OR = 1.3, 95% CI: 1.30-1.31). Additional risk factors include the presence of more than one ruminant species in the same farm (OR = 2.0-2.1, 95% CI: 2.00-2.22), extensive housing system (OR = 4.0, 95% CI: 3.77-4.23), farm age (OR = 1.2, 95% CI: 1.20-1.21), and also co-infection with Paramphistomes (OR = 1.4, 95% CI: 1.10-1.71). The present study underscores the importance of local bovine fasciolosis epidemiology, which could be used to conduct future veterinary and public health programmes to inform effective parasitic management aimed at reducing the prevalence of fasciolosis.

Laboratory Assessment of Molluscicidal Activities of Cannabis sativa, Acacia nilotica, and Tinospora cordifolia Against Snail Host of Fasciola spp.

Background: The potential molluscicidal extracts, obtained from indigenous plants Cannabis sativa, Acacia nilotica, and Tinospora cordifolia, were tested for toxicity against freshwater pulmonate snail Lymnaea acuminata, an intermediate host of Fasciola hepatica. The organic extracts had a significant effect on young snails. Materials and Methods: All organic extracts and column-purified fractions gave median lethal concentrations (19-100.05 mg/L; 24 h) that fell well within the threshold level of 100 mg/L, set for a potential molluscicide by the World Health Organization. Results: The toxicity of T. cordifolia stem acetone extract (96 h LC50: 16.08 mg/L) was more pronounced compared with C. sativa leaf ethanol extract (96 h LC50: 16.32 mg/L) and A. nilotica leaf ethanol extract (96 h LC50: 24.78 mg/L). ß-caryophyllene, gallic acid, and berberine were characterized and identified as active molluscicidal components. Co-migration of ß-caryophyllene (retardation factor [Rf] 0.95), gallic acid (Rf 0.30), and berberine (Rf 0.23) with column-purified parts of Cannabis sativa, Acacia nilotica, and Tinospora cordifolia on thin-layer chromatography demonstrates same Rf value, that is, 0.95, 0.30, and 0.23, respectively. Conclusion: This study indicates that these extracts thus represent potential plant-derived molluscicides that are worthy of further investigations.

Comparative evaluation of real-time PCR and ELISA for the detection of human fascioliasis.

Fascioliasis is a zoonotic parasitic infection caused by Fasciola species in humans and animals. Despite significant advances in vaccination and new therapeutic agents, little attention has been paid to validating methods for the diagnosis of fascioliasis in humans. Serological techniques are convenient assays that significantly improves the diagnosis of Fasciola infection. However, a more sensitive method is required. The aim of this study was to compare the Real-Time PCR technique with the indirect-ELISA for the detection of Fasciola hepatica in human. Using a panel of sera from patients infected with Fasciola hepatica (n = 51), other parasitic infections (n = 7), and uninfected controls (n = 12), we optimized an ELISA which employs an excretory-secretory antigens from F. hepatica for the detection of human fascioliasis. After DNA extraction from the samples, molecular analysis was done using Real-Time PCR technique based on the Fasciola ribosomal ITS1 sequence. Of 70 patient serum samples, 44 (62.86%) samples were identified as positive F. hepatica infection using ELISA and Real-Time PCR assays. There was no cross-reaction with other parasitic diseases such as toxoplasmosis, leishmaniasis, taeniasis, hydatidosis, trichinosis, toxocariasis, and strongyloidiasis. The significant difference between the agreement and similarity of the results of patients with indirect ELISA and Real-Time PCR was 94.4% and 99.2%, respectively (Cohen's kappa ≥ 0.7; P = 0.02). Based on the Kappa agreement findings, the significant agreement between the results of ELISA and Real-Time PCR indicates the accuracy and reliability of these tests in the diagnosis of F. hepatica in humans.

Fasciola spp. in Southeast Asia: A systematic review.

BACKGROUND: Fasciolosis is an emerging public health threat in a number of regions worldwide. To date, we lack an overview of both its occurrence and distribution in Southeast Asia across all actors involved in the life cycle, which impedes the development of disease control measures. Therefore, our objective was to collect recent information on the distribution and the prevalence of Fasciola spp. and the associated risk factors for infection in humans, animals, snails and plant carriers in Southeast Asia. METHODOLOGY: Bibliographic and grey literature databases as well as reference lists of important review articles were searched for relevant records published between January 1st, 2000, and June 30th, 2022. The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for reporting systematic reviews. A total of 3,887 records were retrieved, of which 100 were included in the final analysis. PRINCIPAL FINDINGS: The studies focused mainly on one host species (96.0%), with Fasciola spp. infection in animals being the most studied (72.0%), followed by humans (21.0%). Based on the used inclusion and exclusion criteria, reports were retrieved describing the presence of Fasciola spp. infection in seven out of 11 countries in Southeast Asia. Depending on the diagnostic tool applied, the prevalence of Fasciola spp. infection ranged between 0.3% and 66.7% in humans, between 0% and 97.8% in animals, and between 0% and 66.2% in snails. There were no studies reporting the presence of metacercariae on plant carriers. CONCLUSIONS/SIGNIFICANCE: Our study reconfirms that Fasciola spp. infections are widespread and highly prevalent in Southeast Asia, but it remains difficult to accurately assess the true occurrence of Fasciola spp. in absence of well-designed surveys covering all hosts. As next steps we propose to assess the occurrence of the infection across all actors involved in the transmission, to identify associated risk factors and to estimate the burden of the disease to support national and international decision makers.

Secondary Structure Analysis of Fasciola from Semi-wild Ruminants of Northeast India.

PURPOSE: The objective of this study is to study the secondary structure analysis of Fasciola flukes from a rare mithun host from Manipur. Fascioliasis, a neglected tropical trematodiasis, is poorly studied in India and is widely believed to be predominantly caused by F. gigantica. Through this study, we want to assess the flukes from the rare semi-wild ruminants of Northeast India. This study is important as the mithun population is semi-wild and its population is declining in Manipur. METHODS: Sample collected from the difficult and challenging terrain of Northeast India. The sample was collected from mithun and observed under the microscope. DNA was isolated, sequenced, and analyzed using various bioinformatics tools. The secondary structure analysis of the Internal Transcribed Spacer 2 (ITS2) region was also performed. RESULTS: The secondary structure species tree corroborated the Bayesian inference and, hence, strengthened the phylogeny reconstructed. The annotated ITS2 sequence and RNA secondary of the Manipur isolate displayed the typical four-helix or four-domain model. Helix III reveals the presence of the UGGU motif with other deviations like UGG and GGU. CONCLUSION: This is an in-depth analysis of the secondary structure of Fasciola species. The present study has demonstrated the usefulness of ITS2 and its secondary structures for characterizing parasites. The information on fascioliasis in the mithun's population presents itself useful with regards to their conservation strategy as their populations in both Manipur and Nagaland are dwindling.

Histopathological changes and oxidative stress associated with Fascioliasis in bovines.

Fascioliasis, a prevalent disease in livestock globally, is primarily caused by the trematode parasites Fasciola hepatica and Fasciola gigantica. This parasitic infection leads to significant economic repercussions. In this study, our objective was to gain insight into the pathophysiological consequences of Fascioliasis in cattle through the evaluation of metabolic, oxidative stress, and histological parameters. A thorough investigation was carried out on the liver of 197 bovines after their slaughter, which unveiled the occurrence of Fascioliasis, with a prevalence rate of 13.2% observed. The bovine that were infected exhibited notable increase in serum transaminases (ALT, AST, and ALP) and malondialdehyde (MDA) and catalase (CAT) while the decrease in glutathione (GSH) and superoxide dismutase (SOD) levels. The lipid profile analysis of infected cattle revealed alterations in the cholesterol and triglyceride levels. Moreover, the histopathological examination revealed a range of hepatic lesions associated with Fascioliasis, including necrosis, inflammation, fibrosis, and proliferative alterations. The bile ducts also displayed distinct pathological changes, including hyperplasia, thickening, and edema, and harbored various developmental stages of Fasciola spp. highlighting the parasitic infestation's effects on the biliary system. These results highlight the serious effects of Fascioliasis on lipid metabolism and the oxidative damage that is induced in the livers of cattle. Thus, Fasciola infestation in bovine causes alteration in biochemical and antioxidant activities, which are considered as important factors in the diagnosis of Fascioliasis.

Advances in diagnostic approaches to Fasciola infection in animals and humans: An overviews.

Fasciolosis, caused by Fasciola hepatica and F. gigantica, is an impediment to the livestock industry's expansion and has a massively negative socio-economic impact due to its widespread prevalence in livestock. It is a waterborne zoonosis affecting human populations in the countries where rural economies are associated with livestock rearing. Conventional diagnosis of Fasciola infection is done by detecting parasite eggs in the faeces of infected animals or by immunological methods. Accurate and quick immunodiagnosis of Fasciola infection in animals and humans is based on the detection of antibodies and specific antigens expressed in the prepatent stage of the parasite. Both molecular and serodiagnostic tests developed thus far have enhanced the reliability of Fasciola diagnosis in both man and animals but are not widely available in resource-poor nations. A pen-side diagnostic test based on a lateral flow assay or a DNA test like loop-mediated isothermal amplification (LAMP) would be simple, fast, and cost-effective, enabling clinicians to treat animals in a targeted manner and avoid the development of drug resistance to the limited flukicides. This review focuses on the recent advances made in the diagnosis of this parasite infection in animals and humans.

Immune modulation of goat monocytes by Fasciola gigantica Legumain-1 protein (Fg-LGMN-1).

Legumains belonging to C_13 peptidase family of proteins, and are ubiquitously disseminated among all vertebrate and invertebrate organisms, and have been implicated in innumerable biological and cellular functionality. Herein, we characterized and evaluated immunoregulatory characteristics of Legumain-1 from Fasciola gigantica (Fg-LGMN-1) during its interaction with host immune cells. The isopropyl-ß-d-thiogalactopyranoside (IPTG) stimulated RFg-LGMN-1 protein was positively detected by rat serum containing anti-RFg-LGMN-1 polyclonal antibodies. Furthermore, the uptake of RFg-LGMN-1 by goat monocytes was successfully confirmed using Immunofluorescence Assay (IFA). The immunohistochemical analysis revealed the native localization of LGMN-1 protein on the periphery and internal structures such as suckers, pharynx, and genital pore of the adult parasite, thereby validating its presence in excretory-secretory (ES) products of F. gigantica. The RFg-LGMN-1 co-incubated with concanavalin-A (Con-A) stimulated the increase of interleukin 2 (IL-2), IL-10, and IL-17 in monocytes derived from peripheral blood mononuclear cells (PBMCs) in the concentration-dependent manner. However, the IL-4 cytokine in response to the RFg-LGMN-1 protein declined. These results illuminated the role of LGMN-1 during the parasite-host interface. Our findings elaborated additional evidence that Legumain protein play a role in the manipulating host immune responses during parasite infections. However, further evaluation of RFg-LGMN-1 protein in context of its immunomodulatory roles should be conducted to enhance our understandings of the mechanisms employed by F. gigantica to evade host immune responses.

Geographic expansion of Fasciola hepatica (Linnaeus, 1758) due to changes in land use and cover in Brazil.

Fasciolosis is caused by parasites of the genus Fasciola, affecting animals and humans worldwide. In South America, the disease is a result of infection with Fasciola hepatica and although animal infections are more frequently reported, the full extent of the impact on human health due to underdiagnosis remains uncertain. This study analyzed changes in land use and the distribution of F. hepatica in bovine livers in Brazil over 18 years. Data on land use and land cover were collected from the Mapbiomas Project. Data on 414,481,963 slaughtered cattle and condemned livers due to F. hepatica infection were obtained from 4,433 municipalities. Joinpoint analysis was used to study the time series, and the Susceptible-Infected-Recovered (SIR) model was utilized to explore the behavior of F. hepatica infection. In the North, pasture areas significantly increased (P = 0.000001), while forested areas decreased (P = 0.000001). The midwestern and northern regions concentrated the highest number (>290 million) of cattle slaughtered in Brazil. More than 2 million bovine livers were infected by F. hepatica. The infected cattle originated from 194 municipalities in 2002, increasing to 747 in 2020. We consider that the changes in land use and intense cattle transportation may have caused the expansion of F. hepatica. The SIR model analyzed the spread of the disease looking at all six biomes: Caatinga, Amazon Forest, Cerrado, Pantanal, Atlantic Forest, and Pampa. Moreover, this infection not only threatens the health of animals but is also a major concern to biodiversity and vulnerable human communities in South America. Emblematic biomes such as the Amazon basin already face challenges with logging, desertification, and loss of biodiversity. Therefore, strategies for mitigating infection should include controlling illegal pasture areas, establishing health inspections of animal transport, quarantine of newly arrived animals, and livestock zoning, as well as clear One Health policies.

Coproprevalence, seroprevalence, and geographic distribution of Fasciola spp. infection in beef and dairy cattle in Pak Chong highland, Nakhon-Ratchasima Province, Northeast Thailand.

Fasciola spp. is a major livestock parasite, especially in cattle, water buffalo, sheep, and goats. Infection reduces animal productivity, e.g., meat, dairy, wool and might cause death. In Thailand, reports of Fasciola spp. infection in livestock, especially dairy and beef cattle, are sparse. Pakchong district in Nakhon Ratchasima province is one of Thailand's largest farming areas for dairy and beef cattle, but the prevalence of Fasciola spp. infection has never been reported in this district. The landscape of this area is mainly a hilltop plateau with many water sources suitable for the development of lymnaeid snails, the intermediate host of Fasciola spp., which are essential for the parasite life cycle. This study surveyed the copro- and seroprevalence of Fasciola spp. infection in dairy and beef cattle farmed in Pakchong district by microscope-based examination, PCR, and indirect ELISA. Associated risk factors and geographic information data were collected and analyzed. Paired stool and serum samples were collected from 102 dairy cattle and 99 beef cattle from April to November 2021. Sample analyses demonstrated a high prevalence of Fasciola spp. infection, especially in beef cattle. The overall copro-prevalence was 5.97%, with 0.99% in dairy cattle and 11.11% in beef cattle. The overall seroprevalence was 23.88%, with 2.94% in dairy cattle and 45.45% in beef cattle. Moreover, the data indicated that infection status was not correlated with animal sex and age whereas consumption of natural grasses, water resources, housing floor, and farming system were significant risk factors. Data analysis by a geographic information system (GIS) demonstrated that an associated risk could be farmed in lowering areas, especially in Chan Thuck, Nong Sa Rai, and Khlong Muang subdistricts. In conclusion, this study reports the prevalence of Fasciola spp. infection in cattle in a major farming area of Thailand which could be beneficial for designing parasite control policies in this region as well as adapting this knowledge to other Fasciola spp. endemic areas.

Effects of temperature on the life history traits of intermediate host snails of fascioliasis: A systematic review.

BACKGROUND: The impact of climate change has led to variations in various biological processes, leading to altered transmission dynamics of infectious diseases, including snail-borne diseases (SBDs). Fascioliasis is one of the neglected zoonotic tropical snail-borne diseases caused by the trematode of the genus Fasciola. This review focused on laboratory experimental and model studies that evaluate the potential effect of temperature change on the ecology and biology of the intermediate host snails (IHS) of Fasciola. METHODS: A literature search was conducted on Google Scholar, EBSCOhost, and PubMed databases using predefined medical subject heading terms, Boolean operators, and truncation symbols in combination with direct keywords: Fasciolosis AND Temperature, Lymnaea OR Austropeplea OR Radix OR Galba OR Fossaria OR Pseudosuccinea AND growth, fecundity, AND survival at the global scale. Other search terms used were (Fascioliasis AND Temperature), (Lymnaea AND Temperature), (Austropeplea AND Temperature), (Fossaria AND Temperature), (Galba AND Temperature), (Pseudosuccinea AND Temperature), and (Radix AND Temperature). RESULTS: The final synthesis included thirty-five published articles. The studies reviewed indicated that temperature rise may alter the distribution, and optimal conditions for breeding, growth, and survival of IHS, ultimately resulting in changing the transmission dynamics of fascioliasis. The literature also confirmed that the life history traits of IHS and their interaction with the liver fluke parasites are driven by temperature, and hence climate change may have profound outcomes on the population size of snails, parasite density, and disease epidemiology. CONCLUSION: We concluded that understanding the impact of temperature on the growth, fecundity, and survival of IHS may broaden our knowledge of the possible effects of climate change and hence inform fascioliasis control programs.

Reconstruction of the TGF-ß signaling pathway of Fasciola gigantica.

In the present study, we reconstructed the transforming growth factor beta (TGF-ß) signaling pathway for Fasciola gigantica, which is a neglected tropical pathogen. We defined the components involved in the TGF-ß signaling pathway and investigated the transcription profiles of these genes for all developmental stages of F. gigantica. In addition, the presence of these components in excretory and secretory products (FgESP) was predicted via signal peptide annotation. The core components of the TGF-ß signaling pathway have been detected in F. gigantica; classical and nonclassical single transduction pathways were constructed. Four ligands have been detected, which may mediate the TGF-ß signaling pathway and BMP signaling pathway. Two ligand-binding type II receptors were detected, and inhibitory Smad7 was not detected. TLP, BMP-3, BMP-1, and ActRIb showed higher transcription in 42-day juvenile and 70-day juvenile, while ActRIIa, Smad1, ActRIIb, Smad8, KAT2B, and PP2A showed higher transcription in egg. TLM, Ski, Smad6, BMPRI, p70S6K, Smad2, Smad3, TgfßRI, Smad4, and p300 showed higher transcription in metacercariae. Four ligands, 2 receptors and 3 Smads are predicted to be present in the FgESP, suggesting their potential extrinsic function. This study should help to understand signal transduction in the TGF-ß signaling pathway in F. gigantica. In addition, this study helps to illustrate the complex mechanisms involved in developmental processes and F. gigantica - host interaction and paves the way for further characterization of the signaling pathway in trematodes.