Publications by authors named "Santiago Mas-Coma"

98 Publications

Under pressure: phenotypic divergence and convergence associated with microhabitat adaptations in Triatominae.

Parasit Vectors 2021 Apr 8;14(1):195. Epub 2021 Apr 8.

Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.

Background: Triatomine bugs, the vectors of Chagas disease, associate with vertebrate hosts in highly diverse ecotopes. It has been proposed that occupation of new microhabitats may trigger selection for distinct phenotypic variants in these blood-sucking bugs. Although understanding phenotypic variation is key to the study of adaptive evolution and central to phenotype-based taxonomy, the drivers of phenotypic change and diversity in triatomines remain poorly understood.

Methods/results: We combined a detailed phenotypic appraisal (including morphology and morphometrics) with mitochondrial cytb and nuclear ITS2 DNA sequence analyses to study Rhodnius ecuadoriensis populations from across the species' range. We found three major, naked-eye phenotypic variants. Southern-Andean bugs primarily from vertebrate-nest microhabitats (Ecuador/Peru) are typical, light-colored, small bugs with short heads/wings. Northern-Andean bugs from wet-forest palms (Ecuador) are dark, large bugs with long heads/wings. Finally, northern-lowland bugs primarily from dry-forest palms (Ecuador) are light-colored and medium-sized. Wing and (size-free) head shapes are similar across Ecuadorian populations, regardless of habitat or phenotype, but distinct in Peruvian bugs. Bayesian phylogenetic and multispecies-coalescent DNA sequence analyses strongly suggest that Ecuadorian and Peruvian populations are two independently evolving lineages, with little within-lineage phylogeographic structuring or differentiation.

Conclusions: We report sharp naked-eye phenotypic divergence of genetically similar Ecuadorian R. ecuadoriensis (nest-dwelling southern-Andean vs palm-dwelling northern bugs; and palm-dwelling Andean vs lowland), and sharp naked-eye phenotypic similarity of typical, yet genetically distinct, southern-Andean bugs primarily from vertebrate-nest (but not palm) microhabitats. This remarkable phenotypic diversity within a single nominal species likely stems from microhabitat adaptations possibly involving predator-driven selection (yielding substrate-matching camouflage coloration) and a shift from palm-crown to vertebrate-nest microhabitats (yielding smaller bodies and shorter and stouter heads). These findings shed new light on the origins of phenotypic diversity in triatomines, warn against excess reliance on phenotype-based triatomine-bug taxonomy, and confirm the Triatominae as an informative model system for the study of phenotypic change under ecological pressure .
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http://dx.doi.org/10.1186/s13071-021-04647-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8034103PMC
April 2021

Donkey Fascioliasis Within a One Health Control Action: Transmission Capacity, Field Epidemiology, and Reservoir Role in a Human Hyperendemic Area.

Front Vet Sci 2020 5;7:591384. Epub 2020 Nov 5.

Departamento de Parasitología, Facultad de Farmacia, Universidad de Valencia, Valencia, Spain.

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 and altiplanic snail vector isolates demonstrate that the donkey assures the viability of the whole fasciolid life cycle. Several aspects indicate, however, that 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.
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http://dx.doi.org/10.3389/fvets.2020.591384DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7674489PMC
November 2020

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.

Front Vet Sci 2020 27;7:583204. Epub 2020 Oct 27.

Departamento de Parasitología, Facultad de Farmacia, Universidad de Valencia, Valencia, Spain.

The Northern Bolivian Altiplano is the human fascioliasis hyperendemic area where the highest prevalences and intensities of infection by in humans have been reported. Four animal species are the reservoir species for 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 , 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 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.
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http://dx.doi.org/10.3389/fvets.2020.583204DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7655135PMC
October 2020

Early Postnatal and Preschool-Age Infection by spp.: Report of Five Cases from Vietnam and Worldwide Review.

Am J Trop Med Hyg 2020 10;103(4):1578-1589

Departamento de Parasitología, Facultad de Farmacia, Universidad de Valencia, Valencia, Spain.

Fascioliasis is reported in five Vietnamese children aged 4 years or younger. A 10-month-old girl child and a 12-month-old boy child are the youngest patients ever diagnosed. Eggs in stools suggested an infection occurred at 5-6 months and 7-8 months of age, respectively. DNA sequencing and egg size indicated this to be the first report of a verified infection in so small children. No specific diagnosis could be obtained in two 3-year-old children detected in the acute phase. A big and gravid ectopic -like worm was surgically found in a 4-year-old boy presenting with peritonitis. A worldwide review showed only 38 past cases in preschool children. They included 3, 7, 12, and 16 cases of 1, 2, 3, and 4 years, respectively, with a faster infection increase in males from 2 years onward. Reports were from all continents, except Oceania, including severe complications and death. The causal agent, when specifically diagnosed, was always . Analyses include detection in hospital, surveys, and family outbreaks; infection sources; disease phases; parasite burden; ectopic cases; symptom onset; eosinophilia; biochemical markers; and clinical complications. C-reactive protein, creatinine, and γ-glutamyl transferase are the most useful biomarkers. A serological test and a coprological analysis are recommended for so small children, in which typical symptoms may be overlooked. Treatment problems were described with many drugs, except triclabendazole. Triclabendazole should be considered the drug of choice for such small children. The possibility of a very early infection by spp. should be henceforth considered.
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http://dx.doi.org/10.4269/ajtmh.20-0139DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7543854PMC
October 2020

Impact of fascioliasis reinfection on Fasciola hepatica egg shedding: relationship with the immune-regulatory response.

Acta Trop 2020 Sep 3;209:105518. Epub 2020 May 3.

Departamento de Parasitología, Facultad de Farmacia, Universidad de Valencia, Av. Vicent Andrés Estellés s/n, 46100 Burjassot, Valencia, Spain. Electronic address:

Fascioliasis is a disease caused by liver flukes. In human fascioliasis hyperendemic areas, reinfection and chronicity are the norm. Control strategies in humans require the use of egg count techniques to calculate the appropriate treatment dose for colic risk prevention. The present study investigates how fascioliasis reinfection affects liver fluke egg shedding and its relationship with the immune-regulatory response. The experimental design reproduced the usual reinfection/chronicity conditions in human fascioliasis endemic areas and included Fasciola hepatica primo-infected Wistar rats (PI) and rats reinfected at 4 weeks (R4), 8 weeks (R8), 12 weeks (R12), and negative control rats. In a longitudinal study (0-20 weeks post-infection, p.i.), serical IgG1 levels and eggs per gram of faeces (epg) were analyzed. In a cross-sectional study, the expression of the genes associated with Th1 (Ifng, Il12a, Il12b, Nos2), Th2 (Il4, Arg1), Treg (Foxp3, Il10, Tgfb, Ebi3), and Th17 (Il17) in the spleen and thymus was analyzed. In R8 and R12, transiently higher averages of epg and epg/worm in reinfected groups vs PI group were detected at least in the weeks following reinfection. The kinetics of IgG1 levels shows that reinfected groups followed a pattern similar to the one in the PI group, but transiently higher averages of IgG1 levels in reinfected groups vs the PI group were detected in the weeks following reinfection. Epg correlated with IgG1 levels and also with systemic Il10 and thymic Ifng, and Il10 expression levels. These results suggest that epg depends on the Th1 and Treg phenotype and that the determination of the fluke burden by epg is likely to be an overestimation in cases of recent reinfection in low burden situations. A strategy to facilitate the implementation of epg count techniques and the subsequent decision on the appropriate treatment dose for each patient to prevent colic risk is required.
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http://dx.doi.org/10.1016/j.actatropica.2020.105518DOI Listing
September 2020

COVID-19 and globalization.

One Health 2020 Jun 10;9:100132. Epub 2020 Apr 10.

Health Travel Medicine Program, Vaccine Clinic, Emergency Response Team Development, Florida International University, Miami, USA.

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http://dx.doi.org/10.1016/j.onehlt.2020.100132DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7184197PMC
June 2020

Molecular Characterization of spp. from Some Parts of Iran.

Iran J Public Health 2020 Jan;49(1):157-166

Department of Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

Background: Identification of liver flukes, , and by morphometric parameters is not always reliable due to the overlapping measurements. This study aimed to characterize the liver flukes of animals from different parts of Iran by the genetic markers, ITS1, and .

Methods: We collected flukes from infected livestock in six provinces of Iran from Sep to Nov 2016. The flukes were identified by amplification of a 680 bp sequence of ITS1 locus followed by a restriction fragment polymorphism (RFLP) assay. The genetic diversity among isolates was evaluated by amplification and sequencing of a 493 bp fragment of the gene.

Results: We obtained 38 specimens from Khuzestan, 22 from Tehran, 10 from Isfahan, 10 from Mazandaran, 4 from Kurdistan, and 3 from Ardabil provinces. PCR-RFLP analysis revealed two patterns, representing , and . Fifty specimens from cattle and sheep exhibited pattern and 37 from the cattle, sheep, buffalo, and goat that of . The phylogeny based on revealed two distinct clades separating from . In our phylogeny, the Iranian isolates showed a distinct separation from the African flukes, while grouped with the East Asia specimens demonstrating a common ancestor. The isolates clustered with the flukes from different parts of the world, including East Asia, Europe, and South America.

Conclusion: The present study revealed a substantial genetic difference between populations of Asia and Africa, while isolates from different parts of the world shared high similarities.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7152647PMC
January 2020

Genetically 'pure' Fasciola gigantica discovered in Algeria: DNA multimarker characterization, trans-Saharan introduction from a Sahel origin and spreading risk into north-western Maghreb countries.

Transbound Emerg Dis 2020 Apr 18. Epub 2020 Apr 18.

Departamento de Parasitologia, Facultad de Farmacia, Universidad de Valencia, Burjassot, Valencia, Spain.

Fascioliasis is a freshwater snail-borne zoonotic helminth disease caused by two species of trematodes: Fasciola hepatica of almost worldwide distribution and the more pathogenic F. gigantica restricted to parts of Asia and most of Africa. Of high pathological impact in ruminants, it underlies large livestock husbandry losses. Fascioliasis is moreover of high public health importance and accordingly included within the main neglected tropical diseases by WHO. Additionally, this is an emerging disease due to influences of climate and global changes. In Africa, F. gigantica is distributed throughout almost the whole continent except in the north-western Maghreb countries of Morocco, Algeria and Tunisia where only F. hepatica is present. The present study concerns the DNA multimarker characterization of the first finding of F. gigantica in sheep in Algeria by the complete sequences of rDNA ITS-1 and ITS-2 and mtDNA cox1 and nad1 genes. Sequence comparisons and network analyses show sequence identities and similarities suggesting a south-north trans-Saharan geographical origin, with introduction from Ghana, through the Sahel countries of Burkina Faso and Mali into Algeria. This way perfectly fits with nomadic pastoralism according to interconnecting intranational and transborder herd transhumance routes traditionally followed in this western part of Africa from very long ago. The risk for further spread throughout the three north-western Maghreb countries is multidisciplinarily analysed, mainly considering the present extensive motorization of the intranational transhumance system in Algeria, the lymnaeid snail vector species present throughout the north-western Maghreb, the increasing demand for animal products in the growing cities of northern Algeria and the continued human infection reports. Control measures should assure making anti-fasciolid drugs available and affordable for herders from the beginning and along their transhumant routes and include diffusion and rules within the regional regulatory framework about the need for herd treatments.
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http://dx.doi.org/10.1111/tbed.13572DOI Listing
April 2020

Coalition: Advocacy for prospective clinical trials to test the post-exposure potential of hydroxychloroquine against COVID-19.

One Health 2020 Jun 4;9:100131. Epub 2020 Apr 4.

Departamento de Parasitología, Facultad de Farmacia, Universidad de Valencia, 46100, Valencia, Spain.

Our coalition of public health experts, doctors, and scientists worldwide want to draw attention to the need for high-quality evaluation protocols of the potential beneficial effect of hydroxychloroquine (HCQ) as a post-exposure drug for exposed people. In the absence of an approved, recognized effective pre or post-exposure prophylactic drug or vaccine for COVID-19, nor of any approved and validated therapeutic drug, coupled with social and political pressure raised by publicity both regarding the potential beneficial effect of hydroxychloroquine (HCQ) as well as potential risks from HCQ, we urge the immediate proper clinical trials. Specifically, we mean using HCQ for post-exposure of people with close contact with patients with positive COVID19 rtPCR, including home and medical caregivers. We have reviewed the mechanisms of antiviral effect of HCQ, the risk-benefit ratio taking into consideration the PK/PD of HCQ and the thresholds of efficacy. We have studied its use as an antimalarial, an antiviral, and an immunomodulating drug and concluded that the use of HCQ at doses matching that of the standard treatment of Systemic Lupus erythematous, which has proven safety and efficacy in terms of HCQ blood and tissue concentration adapted to bodyweight (2,3), at 6 mg/kg/day 1 (loading dose) followed by 5 mg/kg/ day, with a maximum limit of 600 mg/day in all cases should swiftly be clinically evaluated as a post-exposure drug for exposed people.
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http://dx.doi.org/10.1016/j.onehlt.2020.100131DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7128742PMC
June 2020

Genetic uniformity, geographical spread and anthropogenic habitat modifications of lymnaeid vectors found in a One Health initiative in the highest human fascioliasis hyperendemic of the Bolivian Altiplano.

Parasit Vectors 2020 Apr 6;13(1):171. Epub 2020 Apr 6.

Departamento de Parasitología, Facultad de Farmacia, Universidad de Valencia, Av. Vicente Andrés Estellés s/n, Burjassot, 46100, Valencia, Spain.

Background: Fascioliasis is a snail-borne zoonotic trematodiasis emerging due to climate changes, anthropogenic environment modifications, and livestock movements. Many areas where Fasciola hepatica is endemic in humans have been described in Latin America altitude areas. Highest prevalences and intensities were reported from four provinces of the northern Bolivian Altiplano, where preventive chemotherapy is ongoing. New strategies are now incorporated to decrease infection/re-infection risk, assessment of human infection sources to enable efficient prevention measures, and additionally a One Health initiative in a selected zone. Subsequent extension of these pilot interventions to the remaining Altiplano is key.

Methods: To verify reproducibility throughout, 133 specimens from 25 lymnaeid populations representative of the whole Altiplano, and 11 used for population dynamics studies, were analyzed by rDNA ITS2 and ITS1 and mtDNA cox1 and 16S sequencing to assess their classification, variability and geographical spread.

Results: Lymnaeid populations proved to belong to a monomorphic group, Galba truncatula. Only a single cox1 mutation was found in a local population. Two cox1 haplotypes were new. Comparisons of transmission foci data from the 1990's with those of 2018 demonstrated an endemic area expansion. Altitudinal, northward and southward expansions suggest movements of livestock transporting G. truncatula snails, with increasing temperatures transforming previously unsuitable habitats into suitable transmission areas. Transmission foci appear to be stable when compared to past field observations, except for those modified by human activities, including construction of new roads or control measures undertaken in relation to fascioliasis.

Conclusions: For a One Health initiative, the control of only one Fasciola species and snail vector species simplifies efforts because of the lower transmission complexity. Vector monomorphism suggests uniformity of vector population responses after control measure implementation. Hyperendemic area outer boundary instability suggests a climate change impact. All populations outside previously known boundaries were close to villages, human dwellings and/or schools, and should therefore be considered during disease control planning. The remarkable southward expansion implies that a fifth province, Aroma, should now be included within preventive chemotherapy programmes. This study highlights the need for lymnaeid molecular identification, transmission foci stability monitoring, and potential vector spread assessment.
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http://dx.doi.org/10.1186/s13071-020-04045-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7137187PMC
April 2020

Human fascioliasis emergence risks in developed countries: From individual patients and small epidemics to climate and global change impacts.

Enferm Infecc Microbiol Clin 2020 Jun - Jul;38(6):253-256. Epub 2020 Feb 24.

Departamento de Parasitología, Facultad de Farmacia, Universidad de Valencia, Valencia, Spain. Electronic address:

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http://dx.doi.org/10.1016/j.eimc.2020.01.014DOI Listing
January 2021

Strongyloidiasis in northern Vietnam: epidemiology, clinical characteristics and molecular diagnosis of the causal agent.

Parasit Vectors 2019 Nov 4;12(1):515. Epub 2019 Nov 4.

Departamento de Parasitología, Facultad de Farmacia, Universidad de Valencia, Av. Vicent Andrés Estellés s/n, Burjassot, 46100, Valencia, Spain.

Background: Strongyloidiasis is a health problem in Vietnam, but appropriate information is still limited. The aim of this study was to determine the prevalence, geographical distribution, epidemiological aspects, symptoms and other health indicators of Strongyloides stercoralis infections in patients from 27 provinces of northern Vietnam attending the Hanoi Medical University Hospital during 2016 and 2017.

Methods: Blood samples of 2000 patients were analyzed for S. stercoralis infection with an IgG ELISA test. Seroprevalence was analyzed by gender, age group, locality of origin (rural or urban areas) and symptoms. Stools from the seropositive patients were examined for the detection of worms which were subsequently used for species identification by morphology and rDNA ITS1 sequencing.

Results: A seroprevalence of 20% was detected, showing an increasing prevalence from young to older age groups but without significant gender difference. Seroprevalence was higher in rural areas than in urban areas, both in general and individually in all provinces without exception, and lower in the mountainous areas than in the large valley lowlands. The follow-up of the 400 patients showed eosinophilia in 100% of cases, diarrhoea in 64.5%, digestion difficulties in 58.0%, stomachache in 45.5%, stomach and duodenal ulcers in 44.5%, itching in 28.0% and fever in 9.5%. The prevalence of symptoms and signs were also higher in older age groups than in younger age groups. Worms were detected in stools of 10.5% of the patients. Sequencing of a 501-bp nuclear ribosomal DNA ITS1 fragment allowed for the verification of infection by Strongyloides stercoralis.

Conclusions: To our knowledge, this study is the largest survey of human strongyloidiasis in Vietnam so far and the first molecular identification of this nematode species in this country. Long-term chronicity may probably be usual in infected subjects, mainly in the older age groups.
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http://dx.doi.org/10.1186/s13071-019-3776-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6829963PMC
November 2019

Lymnaeid Snail Vectors of Fascioliasis, Including the First Finding of Lymnaea neotropica in Ecuador, Assessed by Ribosomal DNA Sequencing in the Southern Zone Close to the Peru Border.

Acta Parasitol 2019 Dec 16;64(4):839-849. Epub 2019 Aug 16.

Departamento de Parasitología, Facultad de Farmacia, Universidad de Valencia, Av. Vicente Andrés Estellés s/n, 46100, Burjassot, Valencia, Spain.

Purpose: Fascioliasis is a freshwater snail-borne zoonotic trematodiasis of high pathogenicity and wide veterinary repercussions. In South America, moreover, it causes serious public health problems, with high human infection rates in Andean countries. Ecuador offers a worrying risky scenario due to its physiography, including many human infection reports and animal endemicity throughout its Andean highlands.

Methods: Endemic areas with increasing animal fascioliasis were surveyed for lymnaeid snails in the province of Loja, southern Ecuador, close to the border of Peru, the country known to present the widest human fascioliasis endemic zone. The altitude of the sampling sites ranged between 150 and 1770 m a.s.l., and their location was close to human villages. Biotopes surveyed were characterized according to fascioliasis transmission needs.

Results: The species Lymnaea schirazensis and L. neotropica were identified by rDNA ITS-2 and ITS-1 sequencing. The non-transmitting L. schirazensis combined haplotype agreed with populations of this species previously reported from northern Ecuador. The finding of the efficient vector L. neotropica is reported for the first time in Ecuador and suggests a passive introduction from neighbouring Peru by uncontrolled livestock transport.

Conclusions: Rice irrigation system implementation, lymnaeid finding on Taraxacum (dandelion) plants which are consumed fresh in salads by people, and Saccharum (sugarcane), whose bark is peeled off with the teeth, represent potential infection sources for humans. The closeness to the Cajamarca human hyperendemic area in northern Peru, where the same two lymnaeids have been also found and triclabendazole resistance reported, is an additional risk to be considered regarding the livestock transborder exchange.
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http://dx.doi.org/10.2478/s11686-019-00104-1DOI Listing
December 2019

Persistent establishment of a tropical disease in Europe: the preadaptation of schistosomes to overwinter.

Parasit Vectors 2019 Jul 29;12(1):379. Epub 2019 Jul 29.

IHPE, University of Montpellier, CNRS, Ifremer, University of Perpignan Via Domitia, 66860, Perpignan, France.

Background: Global changes promote the spread of infectious diseases worldwide. In this context, tropical urogenital schistosomiasis is now permanently established in Corsica since its first emergence in 2013. The local persistence of the tropical pathogens (schistosomes) responsible for urogenital schistosomiasis at such latitudes might be explained by (i) the presence of its intermediate host, the snail Bulinus truncatus, (ii) the recurrent local reseeding of schistosomes by their vertebrate hosts (either human or animal) every summer, and/or (iii) the maintenance and survival of schistosomes within their snail hosts over winter.

Methods: In this study we conducted an ecological experiment to assess the ability of temperate and tropical schistosome strains to survive in classical winter temperatures in Corsican rivers when infecting temperate (local) snail strains. We also quantified the ability of the schistosomes to complete their life-cycle post-overwintering when returned to classical summer water temperatures.

Results: Our results show that Mediterranean molluscs are locally adapted to winter conditions compared to tropical molluscs. Moreover, temperate and tropical schistosome strains equally survived the cold and produced viable offspring when returned to optimal temperatures. These results indicate that schistosomes can overwinter under temperate climates when infecting locally adapted snails and might partly explain the establishment and maintenance of schistosomes in Corsica from year to year.

Conclusions: The observed broader thermal range of schistosomes compared to that of their snail hosts was unexpected and clearly indicates that the spread and establishment of schistosomiasis in temperate countries relies primarily on the presence of the locally adapted snail host lineages, currently known to be present in France, Italy, Portugal, Spain and Greece.
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http://dx.doi.org/10.1186/s13071-019-3635-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6664521PMC
July 2019

Fascioliasis.

Adv Exp Med Biol 2019 ;1154:71-103

Departamento de Farmacia y Tecnología Farmacéutica y Parasitología, Facultad de Farmacia, Universidad de Valencia, Valencia, Spain.

Fascioliasis is a major parasitic disease caused by the digenetic trematodes Fasciola hepatica and Fasciola gigantica. The disease is a well-known veterinary problem of worldwide distribution. Fascioliasis is the vector-borne parasitic disease presenting the widest latitudinal, longitudinal, and altitudinal distribution known at present. In the last two decades, many surveys have shown it to be an important public health problem as well, including estimations of 2.4 million, up to 17 million people, or even higher depending on the hitherto unknown situations mainly in several regions of Asia and Africa. In recent years, the increasing number of human case reports in many countries of the five continents and the results of studies on pathogenicity and immunity, mainly regarding the chronic period of the disease, were the reasons why it was decided to no longer consider fascioliasis merely a secondary zoonotic disease but an important human parasitic disease. In this chapter, we review the most relevant features in relation to fascioliasis, including from the most traditional to the most innovative aspects.
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http://dx.doi.org/10.1007/978-3-030-18616-6_4DOI Listing
September 2019

Angiogenic response in an in vitro model of dog microvascular endothelial cells stimulated with antigenic extracts from Dirofilaria immitis adult worms.

Parasit Vectors 2019 Jun 24;12(1):315. Epub 2019 Jun 24.

Group of Animal and Human Dirofilariosis, Parasitology Area, Faculty of Pharmacy, University of Salamanca, Salamanca, Spain.

Background: Angiogenesis can occur under pathological conditions when stimuli such as inflammation, vascular obstruction or hypoxia exist. These stimuli are present in cardiopulmonary dirofilariosis (Dirofilaria immitis). The aim of this study was to analyze the capacity of D. immitis antigens to modify the expression of angiogenic factors and trigger the formation of pseudocapillaries (tube-like structures) in an in vitro model of endothelial cells.

Methods: The expression of VEGF-A, sFlt, mEndoglin and sEndoglin in cultures of canine microvascular endothelial cells stimulated with extract of adult worms of D. immitis obtained from an untreated dog (DiSA) and from a dog treated for 15 days with doxycycline (tDiSA), was determined by using commercial kits. The capacity of pseudocapillary formation was evaluated analyzing cell connections and cell groups in Matrigel cell cultures stimulated with DiSA and tDiSA. In both cases non-stimulated cultures were used as controls.

Results: First, we demonstrated that worms obtained from the dog treated with doxycycline showed a significantly lower amount of Wolbachia (less than 60%) than worms removed from the untreated dog. Only DiSA was able to significantly increase the expression of the proangiogenic factor VEGF-A in the endotelial cells cultures. None of the D. immitis extracts modified the expression of sFlt. tDiSA extract was able to modify the expression of the endoglins, significantly decreasing the expression of the pro-angiogenic mEndoglin and increasing the anti-angiogenic sEndoglin. The formation of pseudocapillaries was negatively influenced by tDiSA, which reduced the organization and number of cellular connections.

Conclusions: The ability of antigens from adult D. immitis worms to modify the expression of pro and anti-angiogenic factors in endotelial cell cultures was demonstrated, as well as the trend to form pseudocapillaries in vitro. The capacity of stimulation may be linked to the amount of Wolbachia present in the antigenic extracts.
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http://dx.doi.org/10.1186/s13071-019-3570-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6591997PMC
June 2019

Venezuela's humanitarian crisis, resurgence of vector-borne diseases, and implications for spillover in the region.

Lancet Infect Dis 2019 05 21;19(5):e149-e161. Epub 2019 Feb 21.

National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA.

In the past 5-10 years, Venezuela has faced a severe economic crisis, precipitated by political instability and declining oil revenue. Public health provision has been affected particularly. In this Review, we assess the impact of Venezuela's health-care crisis on vector-borne diseases, and the spillover into neighbouring countries. Between 2000 and 2015, Venezuela witnessed a 359% increase in malaria cases, followed by a 71% increase in 2017 (411 586 cases) compared with 2016 (240 613). Neighbouring countries, such as Brazil, have reported an escalating trend of imported malaria cases from Venezuela, from 1538 in 2014 to 3129 in 2017. In Venezuela, active Chagas disease transmission has been reported, with seroprevalence in children (<10 years), estimated to be as high as 12·5% in one community tested (n=64). Dengue incidence increased by more than four times between 1990 and 2016. The estimated incidence of chikungunya during its epidemic peak is 6975 cases per 100 000 people and that of Zika virus is 2057 cases per 100 000 people. The re-emergence of many vector-borne diseases represents a public health crisis in Venezuela and has the possibility of severely undermining regional disease elimination efforts. National, regional, and global authorities must take action to address these worsening epidemics and prevent their expansion beyond Venezuelan borders.
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http://dx.doi.org/10.1016/S1473-3099(18)30757-6DOI Listing
May 2019

Fasciola hepatica infection in children actively detected in a survey in rural areas of Mardan district, Khyber Pakhtunkhawa province, northern Pakistan.

Parasitol Int 2019 Apr 13;69:39-46. Epub 2018 Nov 13.

Departamento de Parasitología, Facultad de Farmacia, Universidad de Valencia, Av. Vicent Andrés Estellés s/n, 46100 Burjassot, Valencia, Spain. Electronic address:

Human fascioliasis is a freshwater snail borne, zoonotic disease caused by Fasciola liver flukes which are widely spread throughout Pakistan and has recently proved to be endemic in humans of the Punjab province. To verify whether fasciolids are also affecting humans outside this province, studies were conducted in four communities comprising rural and urban areas of Mardan district, Khyber Pakhtunkha province, northern Pakistan. Activities comprised two surveys, a coprological one to look for Fasciola infection and another to get information on potential human infection sources and risk factors by means of a questionnaire. Out of 540 subjects of all ages surveyed, only 4 children (0.74%) were found positive for Fasciola eggs: two 9- and 13-year old boys and two 7- and 16-year old girls. Burden per child ranged 73-146 eggs per gram of faeces (epg), with an average of 106 ± 15.4 epg. Based on the egg size, the infection was diagnosed to be caused by F. hepatica. Serum analyses showed eosinophilia and elevated enzyme values in liver function tests. The Mardan area fits well to all transmission and epidemiological requirements of F. hepatica, namely the presence of infected livestock reservoirs throughout, the appropriate climatic factors (mainly monthly temperature variation along the year), and the existence of adequate freshwater collections. The existence of the specific lymnaeid snail vector species for F. hepatica transmission was reported in the neighbouring Swat valley time ago. Results show that human fascioliasis may be widespread in Pakistan and that both F. hepatica and F. gigantica may be involved.
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http://dx.doi.org/10.1016/j.parint.2018.11.003DOI Listing
April 2019

First phenotypic and genotypic description of Fasciola hepatica infecting highland cattle in the state of Mexico, Mexico.

Infect Genet Evol 2018 10 2;64:231-240. Epub 2018 Jul 2.

Departamento de Parasitología, Facultad de Farmacia, Universidad de Valencia, Av. Vicent Andrés Estellés s/n, 46100 Burjassot, Valencia, Spain.

Fascioliasis is a plantborne and zoonotic parasitic disease caused by fasciolid liver flukes. Fasciola hepatica is the only fasciolid species described in the Americas. Human fascioliasis endemic areas are mainly located in high altitude areas of the Americas. Given the necessity to characterize F. hepatica populations involved, the phenotypic and genotypic features of fasciolid adults infecting cattle in the highland area of Toluca, State of Mexico, Mexico, were analyzed and compared to fasciolid materials from the Northern Bolivian Altiplano, representing the altiplanic transmission pattern in a hyperendemic scenario. A computer image analysis system (CIAS) was applied on the basis of standardized measurements. The aforementioned F. hepatica highland populations were compared to standard lowland natural populations of European origin (Spain and France) and F. gigantica of African origin (Burkina Faso). Liver-fluke size was studied by principal component analysis (PCA). Two phenotypic patterns could be distinguished in the F. hepatica material analyzed from the Americas: the valley pattern (Toluca, Mexico) and the altiplanic pattern (Northern Altiplano, Bolivia). PCA showed that the Altiplano population presented a large body size range with a pronouncedly lower minimum size. Mahalanobis distances demonstrated that American populations are very close to European populations. Genetic haplotyping was performed using the ribosomal DNA intergenic region, including ITS-1, 5.8S and ITS-2. The intergenic region was 951 bp-long, providing 2 combined haplotypes due to one mutation appearing in the ITS-2 sequence. Molecular results showed that Fh-1A and Fh-2A, the most frequent haplotypes of F. hepatica from southern Europe, are present in Mexican cattle. Nuclear rDNA biomarkers correlated with adult fluke phenotypic characteristics. Results showed that the Mexican population analyzed and European standard populations presented a phenotypic and genotypic homogeneity, suggesting an introduction with livestock transported during the early colonization period. Results are moreover analyzed in terms of altitude and permanent/seasonal transmission characteristics.
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http://dx.doi.org/10.1016/j.meegid.2018.06.032DOI Listing
October 2018

Human case of Fasciola gigantica-like infection, review of human fascioliasis reports in Nepal, and epidemiological analysis within the South Central Asia.

Acta Parasitol 2018 Sep;63(3):435-443

Departamento de Parasitología, Facultad de Farmacia, Universidad de Valencia, Av. Vicent Andrés Estellés s/n, 46100 Burjassot, Valencia, Spain.

The diagnosis of a 22 year-old male patient from Kerabari, Morang District, Nepal led to the review of human fascioliasis cases and analysis of the epidemiological situation in that country not included in the WHO fascioliasis map. Symptom onset one month before egg detection and normal levels of ALT and AST did not agree with the 3-4-month migratory period of fascioliasis. A shorter acute phase may happen when the main biliary duct is reached by the migratory juveniles directly from the intestinal lumen. The causal agent was ascribed to F. gigantica-like worms after considering adult fluke morphology, altitude of the patient's infection area, fasciolid characteristics in the neighbouring Bangladesh, and lymnaeid snail vector species known in Nepal and in the patient's infection area. Previous reports of human infection by Fasciola in Nepal are reviewed. The patient in question proved to be the twelfth case and the first in whom a F. gigantica-like infection is reported. In Nepal, the wide geographical distribution of livestock fascioliasis, with high prevalences in buffaloes, cattle and goats, and the reports of Fasciola-infected schoolchildren close to the capital Kathmandu, give rise to concern on the situation in remote rural areas in a country where most of the population lives in rural areas. Moreover, the climate change impact in Nepal remembers Pakistan, where human fascioliasis emergence has been related to climate change and man-made irrigation. All in all, the present analysis suggests that human infection by Fasciola may be underestimated in Nepal.
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http://dx.doi.org/10.1515/ap-2018-0053DOI Listing
September 2018

Fasciola hepatica eggs in paleofaeces of the Persian onager Equus hemionus onager, a donkey from Chehrabad archaeological site, dating back to the Sassanid Empire (224-651 AD), in ancient Iran.

Infect Genet Evol 2018 08 24;62:233-243. Epub 2018 Apr 24.

Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran; Center for Research of Endemic Parasites of Iran (CREPI), Tehran University of Medical Sciences, Tehran, Iran. Electronic address:

Fascioliasis is a highly pathogenic zoonotic disease caused by the liver trematodes Fasciola hepatica and F. gigantica. Within the multidisciplinary initiative against this disease, there is the aim of understanding how this disease reached a worldwide distribution, with important veterinary and medical repercussions, by elucidating the spreading steps followed by the two fasciolids from their paleobiogeograhical origins. Fasciola eggs were detected in paleofaeces of a donkey, probably the present-day endangered Persian onager Equus hemionus onager, found in the Chehrabad salt mine archaeological site, Zanjan province, northwestern Iran. The biological remains dated back to the Sassanid period, 224-651 AD. Egg characteristics allowed for their specific ascription to F. hepatica. The interest of this finding relies on the fact of being the first archaeological finding of Fasciola in Asia and the Near East. Moreover, it allows to reach many conclusions about historical, epidemiological and spreading aspects of the disease. The finding in Chehrabad indicates that, at that time, this fasciolid had already spread through the Zagros mountains eastward from the Fertile Crescent. In that region and in ancient Egypt, livestock domestication played a crucial role in facilitating the disease spread during the postdomestication period. Donkeys appear at present to be usually infected by fasciolids in countries of the Fertile Crescent - Ancient Egypt region or neighbouring that region, with prevalences from low to very high. The high pathogenicity and mortality induced by Fasciola in these equines should be considered as an additional potential factor among the causes of the extinctions of E. h. hemippus in Syria, E. h. hydruntinus in the Anatolia-Balkans area, E. h. onager in the Caucasus and maybe also its decline in Iran. Indeed, Eurasiatic wild asses were present in the region and neighbourhood of the Fertile Crescent when the domestication of the livestock reservoirs of Fasciola began.
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http://dx.doi.org/10.1016/j.meegid.2018.04.028DOI Listing
August 2018

Targeted application of an organophosphate-based paint applied on windows and doors against Anopheles coluzzii resistant to pyrethroids under real life conditions in Vallée du Kou, Burkina Faso (West Africa).

Malar J 2018 Apr 2;17(1):136. Epub 2018 Apr 2.

Institut de Recherche en Sciences de la Santé (IRSS)/Centre Muraz, 01 BP 545, Bobo-Dioulasso 01, Burkina Faso.

Background: A novel strategy applying an organophosphate-based insecticide paint on doors and windows in combination with long-lasting insecticide-treated nets (LLINs) was tested for the control of pyrethroid-resistant malaria vectors in a village setting in Vallée du Kou, a rice-growing area west of Burkina Faso.

Methods: Insecticide Paint Inesfly 5A IGR™, comprised of two organophosphates and an insect growth regulator, was applied to doors and windows and tested in combination with pyrethroid-treated LLINs. The killing effect was monitored for 5 months by early morning collections of anophelines and other culicids. The residual efficacy was evaluated monthly by WHO bioassays using Anopheles gambiae 'Kisumu' and local populations of Anopheles coluzzii resistant to pyrethroids. The spatial mortality efficacy (SME) at distances of 1 m was also assessed against pyrethroid-susceptible and -resistant malaria vectors. The frequency of L1014F kdr and Ace-1 G119S mutations was, respectively, reported throughout the study. The Insecticide Paint Inesfly 5A IGR had been tested in past studies yielding a long-term mortality rate of 80% over 12 months against An. coluzzii, the local pyrethroid-resistant malaria vector. The purpose of the present study is to test if treating smaller, targeted surfaces (e.g. doors and windows) was also efficient in killing malaria vectors.

Results: Treating windows and doors alone yielded a killing efficacy of 100% for 1 month against An. coluzzii resistant to pyrethroids, but efficacy reduced quickly afterwards. Likewise, WHO cone bioassays yielded mortalities of 80-100% for 2 months but declined to 90 and 40% 2 and 3 months after treatment, respectively. Mosquitoes exposed to insecticide paint-treated surfaces at distances of 1 m, yielded mortality rates of about 90-80% against local pyrethroids-resistant An. coluzzii during the first 2 months, but decreased to 30% afterwards. Anopheles coluzzii was reported to be exclusively the local malaria vector and resistant to pyrethroids with high L1014 kdr frequency.

Conclusion: The combination of insecticide paint on doors and windows with LLINs yielded high mortality rates in the short term against wild pyrethroid-resistant malaria vector populations. A high SME was observed against laboratory strains of pyrethroid-resistant malaria vectors placed for 30 min at 1 m from the treated/control walls. The application of the insecticide paint on doors and windows led to high but short-lasting mortality rates. The strategy may be an option in a context where low cost, rapid responses need to be implemented in areas where malaria vectors are resistant to pyrethroids.
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http://dx.doi.org/10.1186/s12936-018-2273-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5879594PMC
April 2018

Fasciola hepatica reinfection potentiates a mixed Th1/Th2/Th17/Treg response and correlates with the clinical phenotypes of anemia.

PLoS One 2017 31;12(3):e0173456. Epub 2017 Mar 31.

Centro de Biología Molecular "Severo Ochoa", Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), C/ Nicolás Cabrera 1, Cantoblanco, Madrid, Spain.

Background: Fascioliasis is a severe zoonotic disease of worldwide extension caused by liver flukes. In human fascioliasis hyperendemic areas, reinfection and chronicity are the norm and anemia is the main sign. Herein, the profile of the Th1/Th2/Th17/Treg expression levels is analyzed after reinfection, correlating them with their corresponding hematological biomarkers of morbidity.

Methodology/principal Findings: The experimental design reproduces the usual reinfection/chronicity conditions in human fascioliasis endemic areas and included Fasciola hepatica primo-infected Wistar rats (PI) and rats reinfected at 8 weeks (R8), and at 12 weeks (R12), and negative control rats. In a cross-sectional study, the expression of the genes associated with Th1 (Ifng, Il12a, Il12b, Nos2), Th2 (Il4, Arg1), Treg (Foxp3, Il10, Tgfb, Ebi3), and Th17 (Il17) in the spleen and thymus was analyzed. After 20 weeks of primary infection, PI did not present significant changes in the expression of those genes when compared to non-infected rats (NI), but an increase of Il4, Arg1 and Ifng mRNA in the spleen was observed in R12, suggesting the existence of an active mixed Th1/Th2 systemic immune response in reinfection. Foxp3, Il10, Tgfb and Ebi3 levels increased in the spleen in R12 when compared to NI and PI, indicating that the Treg gene expression levels are potentiated in chronic phase reinfection. Il17 gene expression levels in R12 in the spleen increased when compared to NI, PI and R8. Gene expression levels of Il10 in the thymus increased when compared to NI and PI in R12. Ifng expression levels in the thymus increased in all reinfected rats, but not in PI. The clinical phenotype was determined by the fluke burden, the rat body weight and the hemogram. Multivariate mathematical models were built to describe the Th1/Th2/Th17/Treg expression levels and the clinical phenotype. In reinfection, two phenotypic patterns were detected: i) one which includes only increased splenic Ifng expression levels but no Treg expression, correlating with severe anemia; ii) another which includes increased splenic Ifng and Treg expression levels, correlating with a less severe anemia.

Conclusions/significance: In animals with established F. hepatica infection a huge increase in the immune response occurs, being a mixed Th2/Treg associated gene expression together with an expression of Ifng. Interestingly, a Th17 associated gene expression is also observed. Reinfection in the chronic phase is able to activate a mixed immune response (Th1/Th2/Th17/Treg) against F. hepatica but T and B proliferation to mitogens is strongly suppressed in all infected rats vs control in the advanced chronic phase independently of reinfection The systemic immune response is different in each group, suggesting that suppression is mediated by different mechanisms in each case. Immune suppression could be due to the parasite in PI and R8 rats and the induction of suppressive cells such as Treg in R12. This is the first study to provide fundamental insight into the immune profile in fascioliasis reinfection and its relation with the clinical phenotypes of anemia.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0173456PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5376296PMC
August 2017

DNA multigene characterization of Fasciola hepatica and Lymnaea neotropica and its fascioliasis transmission capacity in Uruguay, with historical correlation, human report review and infection risk analysis.

PLoS Negl Trop Dis 2017 02 3;11(2):e0005352. Epub 2017 Feb 3.

Departamento de Parasitología, Facultad de Farmacia, Universidad de Valencia, Valencia, Spain.

Background: Fascioliasis is a pathogenic disease transmitted by lymnaeid snails and recently emerging in humans, in part due to effects of climate changes, anthropogenic environment modifications, import/export and movements of livestock. South America is the continent presenting more human fascioliasis hyperendemic areas and the highest prevalences and intensities known. These scenarios appear mainly linked to altitude areas in Andean countries, whereas lowland areas of non-Andean countries, such as Uruguay, only show sporadic human cases or outbreaks. A study including DNA marker sequencing of fasciolids and lymnaeids, an experimental study of the life cycle in Uruguay, and a review of human fascioliasis in Uruguay, are performed.

Methodology/principal Findings: The characterization of Fasciola hepatica from cattle and horses of Uruguay included the complete sequences of the ribosomal DNA ITS-2 and ITS-1 and mitochondrial DNA cox1 and nad1. ITS-2, ITS-1, partial cox1 and rDNA 16S gene of mtDNA were used for lymnaeids. Results indicated that vectors belong to Lymnaea neotropica instead of to Lymnaea viator, as always reported from Uruguay. The life cycle and transmission features of F. hepatica by L. neotropica of Uruguay were studied under standardized experimental conditions to enable a comparison with the transmission capacity of F. hepatica by Galba truncatula at very high altitude in Bolivia. On this baseline, we reviewed the 95 human fascioliasis cases reported in Uruguay and analyzed the risk of human infection in front of future climate change estimations.

Conclusions/significance: The correlation of fasciolid and lymnaeid haplotypes with historical data on the introduction and spread of livestock into Uruguay allowed to understand the molecular diversity detected. Although Uruguayan L. neotropica is a highly efficient vector, its transmission capacity is markedly lower than that of Bolivian G. truncatula. This allows to understand the transmission and epidemiological differences between Andean highlands and non-Andean lowlands in South America. Despite rainfall increase predictions for Uruguay, nothing suggests a trend towards a worrying human infection scenario as in Andean areas.
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http://dx.doi.org/10.1371/journal.pntd.0005352DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5310921PMC
February 2017

Human fascioliasis endemic areas in Argentina: multigene characterisation of the lymnaeid vectors and climatic-environmental assessment of the transmission pattern.

Parasit Vectors 2016 05 27;9(1):306. Epub 2016 May 27.

Departamento de Parasitología, Facultad de Farmacia, Universidad de Valencia, Av. Vicente Andrés Estellés s/n, 46100, Burjassot, Valencia, Spain.

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 and Gorczynski continentality index were obtained. Lymnaeid distribution was assessed in environmental studies.

Results: DNA sequences demonstrated the presence of Lymnaea neotropica and L. viator in Locality A and of L. neotropica in Locality B. Two and four new haplotypes were found in L. neotropica and L. viator, respectively. For interspecific differentiation, ITS-1 and 16S showed the highest and lowest resolution, respectively. For intraspecific analyses, cox1 was the best marker and ITS-1 the worst. Shell intraspecific variability overlapped in both species, except maximum length which was greater in L. viator. The desertic-arid conditions surrounding Locality A, the semiaridity-aridity surrounding Locality B, and the very low yearly precipitation in both localities, are very different from the typical fascioliasis transmission foci. Lymnaeids are confined to lateral river side floodings and small man-made irrigation systems. Water availability only depends on the rivers flowing from neighbouring mountains. All disease transmission factors are concentrated in small areas where humans and animals go for water supply, vegetable cultures and livestock farming.

Conclusions: The unusually high number of DNA haplotypes and the extreme climate unsuitable for F. hepatica and lymnaeid development, demonstrate that the transmission foci are isolated. Seasonal transmission may depend on the timely overlap of appropriate temperature and river water availability. Lymnaeids and F. hepatica have probably reached these localities by livestock introduction. DNA differences regarding other populations of L. neotropica and L. viator in Argentina suggest an introduction independent from the spreading movements which allowed these two lymnaeids to expand throughout the country.
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http://dx.doi.org/10.1186/s13071-016-1589-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4882814PMC
May 2016

Outbreak of urogenital schistosomiasis in Corsica (France): an epidemiological case study.

Lancet Infect Dis 2016 08 17;16(8):971-9. Epub 2016 May 17.

Université de Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Université de Montpellier, Perpignan, France.

Background: Schistosomiasis is a snail-borne parasitic disease endemic in several tropical and subtropical countries. However, in the summer of 2013, an unexpected outbreak of urogenital schistosomiasis occurred in Corsica, with more than 120 local people or tourists infected. We used a multidisciplinary approach to investigate the epidemiology of urogenital schistosomiasis in Corsica, aiming to elucidate the origin of the outbreak.

Methods: We did parasitological and malacological surveys at nine potential sites of infection. With the snails found, we carried out snail-parasite compatibility experiments by exposing snails to schistosome larvae recovered from the urine of a locally infected Corsican patient. Genetic analysis of both mitochondrial (cox1) and nuclear (internal transcribed spacer) DNA data from the Schistosoma eggs or miracidia recovered from the infected patients was conducted to elucidate the epidemiology of this outbreak.

Findings: We identified two main infection foci along the Cavu River, with many Bulinus truncatus snails found in both locations. Of the 3544 snails recovered across all sites, none were naturally infected, but laboratory-based experimental infections confirmed their compatibility with the schistosomes isolated from patients. Molecular characterisation of 73 eggs or miracidia isolated from 12 patients showed infection with Schistosoma haematobium, S haematobium-Schistosoma bovis hybrids, and S bovis. Further sequence data analysis also showed that the Corsican schistosomes were closely related to those from Senegal in west Africa.

Interpretation: The freshwater swimming pools of the Cavu River harbour many B truncatus snails, which are capable of transmitting S haematobium-group schistosomes. Our molecular data suggest that the parasites were imported into Corsica by individuals infected in west Africa, specifically Senegal. Hybridisation between S haematobium and the cattle schistosome S bovis had a putative role in this outbreak, showing how easily and rapidly urogenital schistosomiasis can be introduced and spread into novel areas where Bulinus snails are endemic, and how hybridisation could increase the colonisation potential of schistosomes. Furthermore our results show the potential risk of schistosomiasis outbreaks in other European areas, warranting close monitoring and surveillance of all potential transmission foci.

Funding: WHO, ANSES, RICET, and the Ministry of Health and Consumption.
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http://dx.doi.org/10.1016/S1473-3099(16)00175-4DOI Listing
August 2016

CIAS detection of Fasciola hepatica/F. gigantica intermediate forms in bovines from Bangladesh.

Acta Parasitol 2016 Mar;61(2):267-77

Fascioliasis is an important food-borne parasitic zoonosis caused by two trematode species, Fasciola hepatica and Fasciola gigantica. The characterisation and differentiation of Fasciola populations is crucial to control the disease, given the different transmission, epidemiology and pathology characteristics of the two species. Lineal biometric features of adult liver flukes infecting livestock have been studied to characterise and discriminate fasciolids from Bangladesh. An accurate analysis was conducted to phenotypically discriminate between fasciolids from naturally infected bovines (cattle, buffaloes) throughout the country. Morphometric analyses were made with a computer image analysis system (CIAS) applied on the basis of standardised measurements and the logistic model of the body growth and development of fasciolids in the different host groups. Since it is the first ever comprehensive study of this kind undertaken in Bangladesh, the results are compared to pure fasciolid populations of F. hepatica from the European Mediterranean area and F. gigantica from Burkina Faso, geographical areas where both species do not co-exist. Principal component analysis showed that the biometric characteristics of fasciolids from Bangladesh are situated between F. hepatica and F. gigantica standard populations, indicating the presence of phenotypes of intermediate forms in Bangladesh. These results are analysed by considering the present emergence of animal fascioliasis, the local lymnaeid fauna, the impact of climate change, and the risk of human infection in the country.
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http://dx.doi.org/10.1515/ap-2016-0037DOI Listing
March 2016

Epidemiological analysis of human fascioliasis in northeastern Punjab, Pakistan.

Acta Trop 2016 Apr 4;156:157-64. Epub 2016 Jan 4.

Departamento de Parasitología, Facultad de Farmacia, Universidad de Valencia, Av. Vicente Andrés Estellés s/n, 46100 Burjassot, Valencia, Spain. Electronic address:

A coprological study was performed to assess human fascioliasis in 7200 subjects inhabiting rural communities of localities close to the capital city of Lahore in the northeastern part of the very highly populated Punjab province, Pakistan, a country where human infection had never been reported before 2005. The analysis of 1200 subjects including 50 subjects/month throughout a two-year study in each of six localities surveyed provided an overall prevalence of 1.18%, with a range between 0.67% and 1.75% according to localities. Infection rates did not differ according to gender, excepting a higher rate in females (1.13% vs 0.77%) in one locality. Prevalences according to age groups proved to be higher in 11-20 years with 1.57%, followed by 1.18% in 0-10 years and 0.47% in 21-30 years, while no infection above 30 years. Seasonal prevalences proved to be significantly different when comparing summer and autumn with winter and spring. Monthly prevalences showed two peaks, the highest in August (4.67%) and another in January (2.17%). Correlation studies of monthly prevalences with temperature, humidity, rainfall, and pan evaporation showed significant results only with humidity. Despite prevalences being low, the very high number of inhabitants and population densities of the areas surveyed suggest a wide public health problem potentially infecting up to 150,000 rural people, children included, only in the respective districts. Additionally, the situation becomes of more concern when considering the present climate change trend affecting the Punjab, which indicates a progressively increasing fascioliasis transmission risk in that animal endemic area in the near future.
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http://dx.doi.org/10.1016/j.actatropica.2015.12.023DOI Listing
April 2016

Higher physiopathogenicity by Fasciola gigantica than by the genetically close F. hepatica: experimental long-term follow-up of biochemical markers.

Trans R Soc Trop Med Hyg 2016 Jan;110(1):55-66

Departamento de Parasitología, Facultad de Farmacia, Universidad de Valencia, Av. Vicent Andrés Estellés s/n, 46100 Burjassot, Valencia, Spain

Background: Fascioliasis is caused by Fasciola hepatica and F. gigantica. The latter, always considered secondary in human infection, nowadays appears increasingly involved in Africa and Asia. Unfortunately, little is known about its pathogenicity, mainly due to difficulties in assessing the moment a patient first becomes infected and the differential diagnosis with F. hepatica.

Methods: A long-term, 24-week, experimental study comparing F. hepatica and F. gigantica was made for the first time in the same animal model host, Guirra sheep. Serum biochemical parameters of liver damage, serum electrolytes, protein metabolism, plasma proteins, carbohydrate metabolism, hepatic lipid metabolism and inflammation were analysed on a biweekly basis as morbidity indicators. Serum anti-Fasciola IgG, coproantigen and egg shedding were simultaneously followed up.

Results: rDNA and mtDNA sequencing and the morphometric study by computer image analysis system (CIAS) showed that fasciolids used fitted standard species characteristics. Results demonstrated that F. gigantica is more pathogenic, given its bigger size and biomass but not due to genetic differences which are few. Fasciola gigantica shows a delayed development of 1-2 weeks regarding both the biliary phase and the beginning of egg shedding, with respective consequences for biochemical modifications in the acute and chronic periods.

Conclusions: The higher F. gigantica pathogenicity contrasts with previous studies which only reflected the faster development of F. hepatica observed in short-term experiments.
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http://dx.doi.org/10.1093/trstmh/trv110DOI Listing
January 2016