Search results for "fasciola hepatica"
showing 10 items of 84 documents
Modelling the presence of disease under spatial misalignment using Bayesian latent Gaussian models.
2015
Modelling patterns of the spatial incidence of diseases using local environmental factors has been a growing problem in the last few years. Geostatistical models have become popular lately because they allow estimating and predicting the underlying disease risk and relating it with possible risk factors. Our approach to these models is based on the fact that the presence/absence of a disease can be expressed with a hierarchical Bayesian spatial model that incorporates the information provided by the geographical and environmental characteristics of the region of interest. Nevertheless, our main interest here is to tackle the misalignment problem arising when information about possible covar…
Domestic pig prioritized in one health action against fascioliasis in human endemic areas: Experimental assessment of transmission capacity and epide…
2021
The Northern Bolivian Altiplano is the human fascioliasis hyperendemic area where the highest prevalences and intensities in humans have been reported. Preventive chemotherapy was implemented in the last ten years. Surveillance showed high human infection and re-infection rates in between the annual triclabendazole monodose treatments. A complementary One Health control action was launched to decrease the infection risk. Among the multidisciplinary axes, there is the need to establish animal reservoir species priorities for a more efficient control. Laboratory and field studies were performed for the first time to assess the Fasciola hepatica transmission capacity of the pig and its potenti…
Presence of very high prevalence and intensity of infection with Fasciola hepatica among Aymara children from the Northern Bolivian Altiplano.
1997
Abstract Coprological studies of school children from four communities in the Northern Bolivian Altiplano were carried out in order to estimate the prevalences and intensities of Fasciola hepatica infection. Single stool specimens were collected at random from 558 school children (308 boys and 250 girls) aged 5–19 years old. Nineteen different parasite species (13 protozoan and six helminths) were detected. Of the children examined, 98.7% (96.5–100%) presented infection with at least one parasite species. The mean prevalence of 27.6% by Fasciola hepatica (range, 5.9–38.2%) was the highest not only with respect to the helminth species found in the Northern Bolivian Altiplano but also among t…
Specific tyrosine phosphorylation in response to bile in Fasciola hepatica and Echinostoma friedi
2003
Protein tyrosine phosphorylation (PY) is a well-known signalling mechanism which is also involved in host-parasite interactions. Despite its transcendence, PY has been poorly studied in parasitic helminths. The aim of this study is to examine the effect of bile salts on the PY pattern in parasitic trematodes. Two distinct adult models were analysed: Echinostoma friedi, of intestinal habitat, and Fasciola hepatica, naturally inhabitant of host biliary channels. Our results show that bile salts induce specific and distinct protein PY in both trematode species, indicating that this signalling process seems to be also involved in host-trematode relationships.
The revised microRNA complement of Fasciola hepatica reveals a plethora of overlooked microRNAs and evidence for enrichment of immuno-regulatory micr…
2015
MicroRNAs (miRNAs) are gene regulators that have recently been shown to down-regulate the immune response via extracellular vesicles in the mammalian host of helminthic parasites. Using the miRNA prediction pipeline miRCandRef, we expanded the current miRNA set of the liver fluke Fasciola hepatica (Platyhelminthes, Trematoda) from 16 to 54 miRNAs (42 conserved and 13 novel). Comparing the cellular expression levels with extracellular vesicles, we found all miRNAs expressed and enriched for miRNAs with immuno-regulatory function, tissue growth and cancer. Our findings support the hypothesis that miRNAs are the molecular mediators of the previously demonstrated immune modulatory function of e…
Equines as reservoirs of human fascioliasis: transmission capacity, epidemiology and pathogenicity inFasciola hepatica-infected mules
2020
AbstractFascioliasis is a zoonotic disease caused by liver flukes transmitted by freshwater lymnaeid snails. Donkey and horse reservoir roles have been highlighted in human endemic areas. Liver fluke infection in mules has received very limited research. Their role in disease transmission, epidemiological importance andFasciola hepaticapathogenicity are studied for the first time. Prevalence was 39.5% in 81 mules from Aconcagua, and 24.4% in 127 from Uspallata, in high-altitude areas of Mendoza province, Argentina. A mean amount of 101,242 eggs/mule/day is estimated. Lymnaeids from Uspallata proved to belong to ribosomal DNA internal transcribed spacer (ITS) markers ITS-1 and ITS-2 combined…
Human fascioliasis endemic areas in Argentina: multigene characterisation of the lymnaeid vectors and climatic-environmental assessment of the transm…
2016
Background: In South America, fascioliasis stands out due to the human endemic areas in many countries. In Argentina, human endemic areas have recently been detected. Lymnaeid vectors were studied in two human endemic localities of Catamarca province: Locality A beside Taton and Rio Grande villages; Locality B close to Recreo town. Methods: Lymnaeids were characterised by the complete sequences of rDNA ITS-2 and ITS-1 and fragments of the mtDNA 16S and cox1. Shell morphometry was studied with the aid of a computer image analysis system. Climate analyses were made by nearest neighbour interpolation from FAO data. Koeppen & Budyko climate classifications were used. De Martonne aridity index a…
Fasciola hepatica and lymnaeid snails occurring at very high altitude in South America.
2002
Fascioliasis due to the digenean species Fasciola hepatica has recently proved to be an important public health problem, with human cases reported in countries of the five continents, including severe symptoms and pathology, with singular epidemiological characteristics, and presenting human endemic areas ranging from hypo- to hyperendemic. One of the singular epidemiological characteristics of human fascioliasis is the link of the hyperendemic areas to very high altitude regions, at least in South America. The Northern Bolivian Altiplano, located at very high altitude (3800–4100 m), presents the highest prevalences and intensities of human fascioliasis known. Sequences of the internal tran…
Crowding effect on adult growth, pre-patent period and egg shedding of Fasciola hepatica
2006
Fascioliasis pathogenesis depends on fluke burden. In human hyperendemic zones, individual infection intensities reach very high levels and the majority of infected subjects should be in the advanced chronic phase. The rat model offers a useful approach for pathological research in the advanced chronic period. The influence of infection intensity per rat on fluke development, pre-patent period and egg shedding (eggs/g faeces/worm) was analysed in 3 groups (I: 1–3 worms/rat; II: 4–6; III: 7–9). Ontogenetic trajectories of fluke body measures followed a logistic model. Results showed that when the burden increases, the maximum values of fluke measures decrease. The crowding effect is manifest…
Fasciola hepatica development in the experimentally infected black rat Rattus rattus
1998
The finding of natural infection of Rattus rattus by Fasciola hepatica on Corsica has stimulated further research into the role of the black rat in the epidemiology of fascioliasis. Corsican black rats were experimentally individually infected with 20 metacercariae from cattle and murine isolates obtained from naturally infected bovines and black rats. The following results were obtained: (a) in R. rattus infected with the cattle isolate, normal adult fluke development took place and infection persisted for a long period, with emission of eggs showing embryogenic capacity; (b) the development of F. hepatica adults paralleled the ontogenetic trajectories observed in other rodent-F. hepatica …