Browsing by Autor "M. Adela Valero"

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Administration of Triclabendazole Is Safe and Effective in Controlling Fascioliasis in an Endemic Community of the Bolivian Altiplano
(Public Library of Science, 2012) Fidel Villegas; René Angles; René Barrientos; Gary Barrios; M. Adela Valero; Kamal Hamed; Heiner Grueninger; Steven K. Ault; Antonio Montresor; Dirk Engels
Administration of triclabendazole is a feasible, safe and efficacious public health intervention in an endemic community in the Bolivian Altiplano, suggesting that preventive chemotherapy can be applied to control of fascioliasis. Further investigations are needed to define the most appropriate frequency of treatment.
Domestic pig prioritized in one health action against fascioliasis in human endemic areas: Experimental assessment of transmission capacity and epidemiological evaluation of reservoir role
(Elsevier BV, 2021) Santiago Mas‐Coma; Ilra R. Funatsu; René Angles; Paola Buchón; Cristina Mas‐Bargues; Patricio Artigas; M. Adela Valero; M. Dolores Bargues
Donkey Fascioliasis Within a One Health Control Action: Transmission Capacity, Field Epidemiology, and Reservoir Role in a Human Hyperendemic Area
(Frontiers Media, 2020) Santiago Mas‐Coma; Paola Buchón; Ilra R. Funatsu; René Angles; Cristina Mas‐Bargues; Patricio Artigas; M. Adela Valero; M. Dolores Bargues
A One Health initiative has been implemented for fascioliasis control in a human hyperendemic area for the first time. The area selected for this multidisciplinary approach is the Northern Bolivian Altiplano, where the highest prevalences and intensities in humans have been reported. Within the strategic intervention axis of control activities concerning animal reservoirs, complete experimental studies, and field surveys have been performed to assess the fascioliasis transmission capacity and epidemiological role of the donkey for the first time. Laboratory studies with altiplanic donkey-infecting Fasciola hepatica and altiplanic Galba truncatula snail vector isolates demonstrate that the donkey assures the viability of the whole fasciolid life cycle. Several aspects indicate, however, that F. hepatica does not reach, in the donkey, the level of adaptation it shows in sheep and cattle in this high altitude hyperendemic area. This is illustrated by a few-day delay in egg embryonation, longer prepatent period despite similar miracidial infectivity and shorter patent period in the intramolluscan development, lower cercarial production per snail, different cercarial chronobiology, shorter snail survival after shedding end, shorter longevity of shedding snails, and lower metacercarial infectivity in Wistar rats. Thus, the role of the donkey in the disease transmission should be considered secondary. Field survey results proved that liver fluke prevalence and intensity in donkeys are similar to those of the main reservoirs sheep and cattle in this area. Fasciolid egg shedding by a donkey individual contributes to the environment contamination at a rate similar to sheep and cattle. In this endemic area, the pronounced lower number of donkeys when compared to sheep and cattle indicates that the epidemiological reservoir role of the donkey is also secondary. However, the donkey plays an important epidemiological role in the disease spread because of its use by Aymara inhabitants for good transport, movements, and travel from one locality/zone to another, a repercussion to be considered in the present geographical spread of fascioliasis in the Altiplano due to climate change. Donkey transport of parasite and vector, including movements inside the zone under control and potential introduction from outside that zone, poses a problem for the One Health initiative.
Fascioliasis in Llama, Lama glama, in Andean Endemic Areas: Experimental Transmission Capacity by the High Altitude Snail Vector Galba truncatula and Epidemiological Analysis of Its Reservoir Role
(Multidisciplinary Digital Publishing Institute, 2021) Santiago Mas‐Coma; M.M. Cafrune; Ilra R. Funatsu; Atílio J. Mangold; René Angles; Paola Buchón; Cecilia Fantozzi; Patricio Artigas; M. Adela Valero; M. Dolores Bargues
South American camelids are definitive hosts of Fasciola hepatica. However, their capacity to participate in the transmission and epidemiology of fascioliasis has never been appropriately studied. Therefore, an F. hepatica isolate from Argentine llama is for the first time analyzed using Galba truncatula lymnaeids from Bolivia. Experimental follow-up studies included egg embryogenesis, miracidial infection of lymnaeid snails, intramolluscan larval development, cercarial production, chronobiology of cercarial shedding, vector survival to infection, and metacercarial infectivity of mammal host. Shorter prepatent and patent periods were leading to markedly lower cercarial production, shorter cercarial shedding, and a higher negative impact on snail survival. The usually low liver fluke prevalences and intensities and low daily fecal outputs indicate that llamas do not substantially contribute to fascioliasis transmission. The defecating behavior in dung piles far from freshwater collections prevents lymnaeid infection by eggs shed by this camelid. All results suggest the reservoir role of the llama to be negligible and, therefore, no priority within control measures in endemic areas. However, llamas may play a disease-spreading role if used as pack animals in rural areas. In the Northern Bolivian Altiplano human hyperendemic area, neither llamas nor alpacas should be considered for control measures within a One Health action.
Field Evaluation of a Coproantigen Detection Test for Fascioliasis Diagnosis and Surveillance in Human Hyperendemic Areas of Andean Countries
(Public Library of Science, 2012) M. Adela Valero; María Victoria Periago; Ignacio Pérez‐Crespo; René Angles; Fidel Villegas; C. Aguirre; W Strauss; José R. Espinoza; Patricia Herrera-Velit; Angélica Terashima
The coproantigen-detection test allows for high sensitivity and specificity, fast large mass screening capacity, detection in the chronic phase, early detection of treatment failure or reinfection in post-treated subjects, and usefulness in surveillance programs. However, this technique falls short when evaluating the fluke burden on its own.
Helminth/Protozoan Coinfections in Chronic Fascioliasis Cases in Human Hyperendemic Areas: High Risk of Multiparasitism Linked to Transmission Aspects and Immunological, Environmental and Social Factors
(Multidisciplinary Digital Publishing Institute, 2025) M. Adela Valero; María Morales‐Suárez‐Varela; Davis J. Marquez-Guzman; René Angles; José R. Espinoza; Pedro Ortiz; Filippo Curtale; M. Dolores Bargues; Santiago Mas‐Coma
Research is required to determine whether the coinfections by Fasciola spp. and other parasite species result from poor rural hygiene or reflect underlying epidemiological patterns and causes. Therefore, the role of fascioliasis is analyzed concerning coinfection complexity, risk of multiparasitism, parasite associations, pathogenic implications and their multifactorial causes. Helminth and protozoan coinfections are studied in 2575 previously untreated individuals from four rural hyperendemic areas (Northern Bolivian Altiplano, Peruvian Altiplano and Cajamarca valley, and the Egyptian Nile Delta). This cross-sectional study was conducted from January 2011 to December 2023. Coinfections were coprologically assessed by the merthiolate-iodine-formalin and formol-ether concentration techniques. Infection intensity was measured as eggs/gram of feces (epg) with the Kato-Katz technique. Parasite and coinfection prevalences were stratified by age, sex and geographical location. High mixed infections, fascioliasis prevalences and very low non-coinfected Fasciola-infected subjects were associated with the following regions: Bolivian Altiplano, 96.5%, 16.8% and 3.5%; Peruvian Altiplano, 100%, 24.6% and 0%; Cajamarca valley, 98.7%, 21.4% and 1.8%; Nile Delta, 84.1%, 13.0% and 15.9%. Transmission routes and human infection sources underlie fascioliasis associations with protozoan and other helminth infections. Prevalence pattern of protozoan-helminth coinfections differed between Fasciola-infected individuals and individuals not infected with Fasciola, presenting higher prevalences in individuals with fascioliasis. Multiparasitism diagnosed in Fasciola-infected subjects included coinfections by up to nine parasite species, eight protozoan species, and five helminth species. The most prevalent pathogenic protozoan was Giardia intestinalis. The most prevalent helminth species differ according to environmental conditions. Several parasites indicate fecal environmental contamination. When the fascioliasis burden increases, the total number of parasite species also increases. The fascioliasis risk increases when the total helminth species number/host increases. Fasciola-infected subjects may present a modification in the clinical phenotypes of coinfecting parasitic diseases. Fascioliasis coinfection factors include transmission ways and immunological, environmental and social aspects. Coinfections must be considered when assessing the health impact of fascioliasis, including the analysis of the fascioliasis effects on malnutrition and physical/intellectual child development. Fascioliasis-control schemes should, therefore, integrate control measures mainly against other helminthiases.
One Health Action against Human Fascioliasis in the Bolivian Altiplano: Food, Water, Housing, Behavioural Traditions, Social Aspects, and Livestock Management Linked to Disease Transmission and Infection Sources
(Multidisciplinary Digital Publishing Institute, 2022) René Angles; Paola Buchón; M. Adela Valero; M. Dolores Bargues; Santiago Mas‐Coma
The Northern Bolivian Altiplano is the fascioliasis endemic area with the reported highest human prevalence and intensities. A multidisciplinary One Health initiative was implemented to decrease infection/reinfection rates detected by periodic monitoring between the ongoing yearly preventive chemotherapy campaigns. Within a One Health axis, the information obtained throughout 35 years of field work on transmission foci and affected rural schools and communities/villages is analysed. Aspects linked to human infection risk are quantified, including: (1) geographical extent of the endemic area, its dynamics, municipalities affected, and its high strategic importance; (2) human population at risk, community development and mortality rates, with emphasis on problems in infancy and gender; (3) characteristics of the freshwater collections inhabited by lymnaeid snail vectors and constituting transmission foci; (4) food infection sources, including population surveys with questionnaire and reference to the most risky edible plant species; (5) water infection sources; (6) household characteristics; (7) knowledge of the inhabitants on Fasciola hepatica and the disease; (8) behavioural, traditional, social, and religious aspects; (9) livestock management. This is the widest and deepest study of this kind ever performed. Results highlight prevention and control difficulties where inhabitants follow century-old behaviours, traditions, and beliefs. Intervention priorities are proposed and discussed.
Potentially pathogenic free-living amoebae at very high altitude: Detection by multiplex qPCR in the Northern Altiplano fascioliasis hyperendemic area in Bolivia
(Elsevier BV, 2025) Patricia Pérez-Pérez; Patricio Artigas; María Reyes-Batllé; Elizabeth Córdoba-Lanús; Rubén L. Rodríguez-Expósito; Pablo Cuervo; Angélica Domínguez-de-Barros; Omar García-Pérez; M. Adela Valero; Ashley Elias
Sheep and Cattle Reservoirs in the Highest Human Fascioliasis Hyperendemic Area: Experimental Transmission Capacity, Field Epidemiology, and Control Within a One Health Initiative in Bolivia
(Frontiers Media, 2020) Santiago Mas‐Coma; Paola Buchón; Ilra R. Funatsu; René Angles; Patricio Artigas; M. Adela Valero; M. Dolores Bargues
The Northern Bolivian Altiplano is the human fascioliasis hyperendemic area where the highest prevalences and intensities of infection by Fasciola hepatica in humans have been reported. Four animal species are the reservoir species for F. hepatica in this area, namely, sheep, cattle, pigs, and donkeys. Livestock for the Aymara inhabitants is crucial because vegetable cultures are not viable due to the inhospitality of the very high altitude of 3,820-4,100 m. A One Health initiative has been implemented in this area in recent years, as the first such control action in a human endemic area ever. Among the different control axes included, special focus is devoted to the two main reservoirs sheep and cattle. Egg embryonation, miracidial infectivity, intramolluscan development, cercarial production, infected snail survival, and metacercarial infectivity were experimentally studied in altiplanic sheep and cattle isolates. These laboratory studies were performed using altiplanic isolates of the lymnaeid species Galba truncatula, the only vector present in the hyperendemic area. Experiments were made at constant 12 h day/12 h night and varying 20/20°C and 22/5°C photoperiods. Infections were implemented using mono-, bi-, and trimiracidial doses. Results demonstrate that sheep and cattle have the capacity to assure F. hepatica transmission in this very high-altitude area. Field surveys included prevalence studies by coprology on fecal samples from 1,202 sheep and 2,690 cattle collected from different zones of the Northern Bolivian Altiplano. Prevalences were pronouncedly higher and more homogeneous in sheep (63.1%; range: 38.9-68.5%) than in cattle (20.6%; range: 8.2-43.3%) in each one of the different zones. Although similarities between the prevalences in sheep and cattle appeared in the zones of the highest and lowest infection rates, this disappeared in the other zones due to cattle treatments. Comparison with past surveys demonstrates that this hyperendemic area is stable from the disease transmission point of view. Therefore, the control design should prioritize sheep and cattle within the One Health action. Studies performed in the Bolivian Altiplano furnish a baseline for future initiatives to assess the transmission and epidemiological characteristics of fascioliasis in the way for its control in other high altitude Andean endemic areas.