Accurate and rapid detection of Fasciola hepatica copro-DNA in sheep using loop-mediated isothermal amplification (LAMP) technique

Conventional and Advanced Methods Used for the Diagnosis of Fascioliosis, a Food-Borne Zoonotic Disease

Fascioliosis is a food-borne zoonotic helminth infection caused by flatworms belonging to the family Fasciolidae, primarily affecting ruminants. The chronic form of fascioliosis is the most prevalent and is characterized by anemia, weight loss, cirrhosis, and liver dysfunction, along with atrophy, jaundice, and bottle jaw. In humans, infection results in fever, nausea, skin rashes, and severe abdominal pain. Climate changes and human-driven environmental alterations have contributed to an increasing incidence of fascioliosis in various regions. Fasciola species are widely distributed and have a high occurrence in tropical countries. Approximately 2.4-17 million humans are afflicted by fascioliosis in tropical and subtropical areas, with an additional 180 million facing the risk of infection. Fascioliosis poses a notable threat to ruminants; over 700 million production animals are at risk, and global annual financial losses surpass $3.2 billion. Conventional coprological methods and advanced molecular techniques are employed to diagnose fascioliosis in animals and humans. Within endemic areas, timely and accurate diagnosis is critical for successful prevention and treatment. Molecular approaches such as various PCR techniques and serological methods are extensively utilized to diagnose fascioliosis. In this review, we describe various conventional coprological and advanced DNA-based PCR techniques along with serological methods used for the screening, monitoring, and specific diagnosis of clinical and subclinical fascioliosis in humans and animals. The information accumulated in this review will be helpful for the diagnosis of fascioliosis in the field and research laboratories.

Direct or DNA Extraction-Free Amplification and Quantification of Foodborne Pathogens

The use of direct nucleic acid amplification of pathogens from food matrices has the potential to reduce time to results over DNA extraction-based approaches as well as traditional culture-based approaches. Here we describe protocols for assay design and experiments for direct amplification of foodborne pathogens in food sample matrices using loop-mediated isothermal amplification (LAMP) and polymerase chain reaction (PCR). The examples provided include the detection of Escherichia coli in milk samples and Salmonella in pork meat samples. This protocol includes relevant reagents and methods including obtaining target sequences, assay design, sample processing, and amplification. These methods, though used for specific example matrices, could be applied to many other foodborne pathogens and sample types.

Rapid and multiple visual detection of Fasciola hepatica in feces via recombinase polymerase amplification integrated with CRISPR/Cas12a technology

Fasciola hepatica is a foodborne zoonotic parasite causing significant economic losses and impacting human and livestock health in resource-limited regions. We developed a rapid, reliable, and sensitive detection method combining recombinase polymerase amplification (RPA) with CRISPR/Cas12a, allowing visualization with the naked eye or a fluorescence reader. Multiple visual methods were used to analyze the assay results. Fluorescence signals were collected using a fluorescence reader or observed under UV or blue light. Lateral flow strips (LFS) were used for visual detection. Among seven primer pairs and three CRISPR RNA (crRNA) screened, F1/R1 and crRNA3 were optimal. The Cas12a reaction buffer was optimized with 50 mM Tris-HCl and 80 mM NaCl, with an RPA reaction time of 20 min. The assay showed high specificity and excellent sensitivity for F. hepatica, detecting 0.122 copies/μL with fluorescence and 8.6 copies/μL with LFS. Testing of 143 sheep and 43 human fecal samples showed 98.39 % consistency with qPCR and nested PCR, with prevalence rates of 52.45 % and 18.6 % in sheep and humans, respectively. Our assay offers substantial potential for point-of-care testing in resource-limited areas, addressing the need for rapid and accurate diagnosis of F. hepatica.

Prevalence of Fasciola hepatica infection in slaughtered sheep from Northwest Tunisia and its risk factors: Association with gastrointestinal helminths infection and anaemia

We investigated herein the prevalence of Fasciola hepatica infection in sheep at Sejnane slaughterhouse, governorate of Bizerte, Northwest of Tunisia, using three different diagnostic techniques (liver dissection, bile examination, and coprology). Faeces, liver, gall bladder as well as blood samples were collected from 603 slaughtered sheep in two seasons: winter and summer. Faecal egg counts of F. hepatica were estimated using sedimentation technique. Livers were examined for the presence of flukes, and bile collected from gall bladder was examined by sedimentation technique for the presence of F. hepatica eggs. Faecal egg counts of gastrointestinal helminths were estimated using flotation followed by the McMaster technique. Blood samples were used to estimate blood cell count (RBC) (×106/mL), haemoglobin (Hb) (g/dL), and haematocrit (Ht) (%) levels. A total of 1714 F. hepatica flukes were collected from 68 infected livers, the number of flukes per sheep ranged between naught and 195. Bile examination (16.78% ± 1.83; 51/310) showed the higher infection prevalence, followed by liver dissection (11.28% ± 1.17; 68/603) and coprology (9.12% ± 1.08; 55/603) (p = 0.015). Infection prevalences were significantly higher in young sheep aged of less than 1 year (8.13% ± 1.22; 49/498), in cross-bred sheep (10.61% ± 1.39%; 64/478), and in summer (7.13% ± 1.82; 43/293) (p < 0.05). There was no significant difference in infection prevalence by gastrointestinal helminths in F. hepatica-infected and F. hepatica-non-infected animals (p > 0.05). The overall prevalence of F. hepatica-infected anaemic sheep was higher (22.73% ± 4.47; 20/88) than F. hepatica-non-infected anaemic sheep (p < 0.05). Fasciola hepatica infection is frequent in sheep from Sejnane representing hence an important constraint for the development of the sheep industry in this region. Therefore, it is necessary to establish and implement a specific control programme to reduce fasciolosis infection risks including animal owners' education.

Advancement in Diagnosis, Treatment, and Vaccines against Fasciola hepatica: A Comprehensive Review

In this review article, we aim to provide an overview of fasciolosis in ruminants. Diagnosis through new coprological methods (such as Flukefinder®, FLOTAC®, and Mini-FLOTAC®) remains the most suitable approach for farms. Regarding treatment, there is a scarcity of available drugs, and resistance to them has prompted new approaches (including drug combinations, enhanced metabolism, or the use of natural compounds) to address this issue. Additionally, several researchers have developed vaccines to control the disease, but their efficacy varies, and none are currently sufficient for commercial use. Further studies are needed to better understand all aspects discussed in this manuscript, with the goal of improving diagnosis, treatment, and disease control. It is important to note that this manuscript does not delve into in-depth knowledge of the discussed aspects; rather, it provides an overview of the different methodologies related to these three aspects of parasitic disease.

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.

Eukaryotic Infections in Dairy Calves: Impacts, Diagnosis, and Strategies for Prevention and Control

Eukaryotic infections are common among dairy calves and can have significant impacts on their health and growth rates. Fungal infections caused by Aspergillus fumigatus, Trichophyton verrucosum, and Candida albicans can cause respiratory diseases, dermatophytosis, and diarrhea, respectively. Protozoan parasites, including Cryptosporidium parvum, Giardia duodenalis, and Eimeria spp., are also common in dairy calves. C. parvum is highly contagious and can cause severe diarrhea and dehydration, while Giardia duodenalis can lead to poor growth and is transmissible to humans through contaminated food or water. Eimeria spp. can cause coccidiosis and lead to reduced growth rates, poor feed conversion, and death. The common helminthic infections in dairy calves include Ostertagia ostertagi, Cooperia spp., Fasciola hepatica, and Strongyloides papillosus. These parasitic infections significantly impact calf health, growth, and dairy industry productivity. Diagnosis of these infections can be made through fecal samples using microscopy or molecular methods. However, diagnosis of the infections can be challenging and requires a combination of clinical signs and laboratory tests such as culture and PCR. Preventing and controlling eukaryotic infections in dairy calves requires several measures. Good hygiene and sanitation practices, proper management strategies, and timely treatment of affected animals are important. It is also necessary to avoid overcrowding and consider vaccination against ringworm. Further research is needed to better understand the epidemiology and characterization of eukaryotic infections in dairy calves, which will help in the development of more effective prevention and control strategies. In general, good hygiene practices, appropriate management strategies, and timely treatment of affected animals are crucial in preventing and controlling the infections, ensuring the health and well-being of dairy calves.

Multiplex PCR and Sequence Analysis to Investigate Genetic Diversity of Fasciola Isolates from Cattle and Sheep in Turkey

Fasciolosis is a highly prevalent helminthic infection caused by Fasciola hepatica and F. gigantica. With the aim of identifying hybrid Fasciola flukes, multiplex PCR was performed to amplify the pepck gene. Furthermore, to determine Fasciola haplotypes, mitochondrial nad1 gene was amplified and sequenced, and phylogenetic analyses were performed. Adult Fasciola isolates were collected from 51 cattle and 51 sheep, genomic DNA was isolated, and one-step multiplex PCR was subsequently performed to amplify pepck. Isolates that generated a 510 bp band were identified as F. gigantica, those that generated a 241 bp band were identified as F. hepatica, and those that generated both bands were identified as hybrid (aspermic) flukes. Multiplex PCR data identified four isolates as F. gigantica and 84 as F. hepatica. Fourteen hybrid isolates (five cattle and nine sheep) were identified. On unidirectional DNA sequence analysis of nad1 PCR products, three sequences were identified as F. gigantica and 99 as F. hepatica. In addition, only 4 of 87 haplotypes detected for F. hepatica nad1 sequences were found to be previously reported, while the remaining 83 are unique to this study. To summarize, this study is the first to report the existence of hybrid Fasciola flukes and 83 unique haplotypes of F. hepatica in Turkey.

Fasciolosis—An Increasing Challenge in the Sheep Industry

Simple Summary

Fasciolosis caused by Fasciola hepatica is a serious disease and a huge challenge in the sheep industry. The disease has several clinical manifestations including acute death, anemia, ill-thrift and loss of body condition. Climate change with milder temperatures and heavier rainfall will increase the risk of fasciolosis. Grazing management and treatment with flukicide are at present the only options to restrain F. hepatica infection. However, control possibilities are challenging, and resistance to flukicide drugs is increasing. Diagnostic improvements, targeted treatment and vaccines will hopefully increase animal health and welfare on fluke infested pastures in the future.

Abstract

The liver fluke Fasciola hepatica may cause severe infection in several mammalian species, including sheep and humans. Fasciolosis is a parasitic disease occurring worldwide in temperate climates and involves intermediate lymnaeid snails as vectors, in Europe the pond snail Galba truncatula in particular. In the sheep industry, the disease is a serious welfare and health problem. Fasciolosis is usually classified as acute, subacute or chronic according to the number and stage of flukes present in the liver, but with a considerable overlap. Acute disease, associated with a large number of migrating larvae, often results in sudden death due to acute and massive hemorrhage, while chronic fasciolosis is characterized by anemia, hypoalbuminaemia and weight loss. The management of fasciolosis is an increasing challenge in the sheep industry. Early diagnostic tests are limited. Protective immunity against liver flukes in sheep is low or lacking, and vaccines are not yet available. Treatment and control possibilities are challenging, and resistance to flukicide drugs is increasing. In addition, climate change with warmer and more humid weather will have a substantial effect on the establishment of both flukes and snails and will most likely increase the future distribution of F. hepatica.

Accurate and rapid detection of Fasciola hepatica copro-DNA in sheep using loop-mediated isothermal amplification (LAMP) technique

Fascioliasis is a parasitic infection caused by Fasciola spp. in humans and animals. Despite significant advances in vaccination and new therapeutic agents, little attention has been paid to validate methods for the diagnosis of fascioliasis in animals. This study aimed to compare the loop‐mediated isothermal amplification (LAMP) technique with PCR assay for the diagnosis of F. hepatica in sheep. In this cross‐sectional study, 195 stool samples were collected from sheep for 3 months in Lorestan province, West of Iran. Specimens’ parasitological examination was performed by using the direct wet mount and formalin‐ether concentration method. After DNA extraction from the samples, molecular analysis was done using PCR and LAMP techniques based on the Fasciola ribosomal intergenic spacer (IGS) sequence. Of 195 specimens of sheep, 11 specimens were identified as F. hepatica‐positive infection by using microscopic, PCR and LAMP assays. Kappa agreement test results showed that there was a significant agreement between the results of microscopic examination diagnostic tests, PCR and LAMP (Kappa = 0.51–0.72 and p < .001). According to the results of chi‐square comparisons between parasite prevalence applying different techniques and variables of age, sex breed, and type of drinking water, there was no significant relationship (p ≥ .05). However, most of the infected sheep with Fasciola were 3‐ to 4‐year‐old females, of the Lori breed and consumed tap water. In many endemic areas, successful prevention and treatment of fascioliasis in animals depend on rapid and accurate diagnosis. Based on the results of the Kappa agreement, the significant agreement among the results of the microscopic examination, PCR and LAMP indicates the accuracy and reliability of these tests in the diagnosis of F. hepatica in sheep. However, molecular methods, especially the LAMP technique, are suggested because of their higher sensitivity and reliability for the diagnosis of F. hepatica even under field conditions.