0000000000142721
AUTHOR
M. A. Valero
Phenotypes of intermediate forms of Fasciola hepatica and F. gigantica in buffaloes from Central Punjab, Pakistan.
AbstractFascioliasis is an important food-borne parasitic disease caused by the two trematode species, Fasciola hepatica and Fasciola gigantica. The phenotypic features of fasciolid adults and eggs infecting buffaloes inhabiting the Central Punjab area, Pakistan, have been studied to characterize fasciolid populations involved. Morphometric analyses were made with a computer image analysis system (CIAS) applied on the basis of standardized measurements. Since it is the first study of this kind undertaken in Pakistan, the results are compared to pure fasciolid populations: (a) F. hepatica from the European Mediterranean area; and (b) F. gigantica from Burkina Faso; i.e. geographical areas wh…
Human fascioliasis infection sources, their diversity, incidence factors, analytical methods and prevention measures
AbstractHuman fascioliasis infection sources are analysed for the first time in front of the new worldwide scenario of this disease. These infection sources include foods, water and combinations of both. Ingestion of freshwater wild plants is the main source, with watercress and secondarily other vegetables involved. The problem of vegetables sold in uncontrolled urban markets is discussed. Distinction between infection sources by freshwater cultivated plants, terrestrial wild plants, and terrestrial cultivated plants is made. The risks by traditional local dishes made from sylvatic plants and raw liver ingestion are considered. Drinking of contaminated water, beverages and juices, ingestio…
Anaemia in advanced chronic fasciolosis
Abstract The association between fasciolosis-induced anaemia and related factors has been quantified in a rodent model. Haematological parameters were analysed in Wistar rats at 20 and 60 weeks post-infection (p.i.). Pigment stones and bile specimens were collected. Serum IgG1, IgG2a and IgE were determined in rat serum samples. Cytokine levels have been correlated with haematological parameters. The screening for gastrointestinal bleeding was carried out. Bacteriological bile cultures revealed viable bacteria in 53.8% of specimens at 60 weeks p.i. The results show that the type of anaemia in fasciolosis might be considered a biomarker of the chronicity period of the disease, changing from …
Analysis of climatic data and forecast indices for human fascioliasis at very high altitude
Human infection with Fasciola hepatica has recently been recognized as an important health problem worldwide, and particularly at very high altitudes in South America. The highest prevalences and intensities of human fascioliasis known are those of the northern Bolivian Altiplano, where infected Lymnaea truncatula occur at altitudes of 3800-4100 m. In the present study, the climatic data for this area of the Altiplano, which differ markedly from those of endemic areas in the lowlands, were analysed. There is no marked seasonality in temperature but there are large variations in temperature within a daily, 24-h period. Rainfall is seasonal, with a long dry season, coinciding with the lowest …
Developmental differences in the uterus of Fasciola hepatica between livestock liver fluke populations from Bolivian highlands and European lowlands
A morphometric study of the uterus area (UA) of Fasciola hepatica adults was carried out with the aid of a computer linked to a stereomicroscopic 3CCD colour video camera using image analysis software. The UA of adult liver flukes found in naturally infected sheep, cattle and pig from the endemic human fascioliasis zone of the northern Bolivian Altiplano highlands was compared with that of flukes found infecting sheep and cattle from Valencia, Spain and cattle from Corsica, France (collectively, European lowlands). Liver fluke UA was examined using an allometric model. A comparison of the allometry of the liver fluke UA in different host species from Bolivia revealed no significant differen…
Differentiation of Trichuris species eggs from non-human primates by geometric morphometric analysis
Human trichuriasis is a neglected tropical disease which affects millions of people worldwide, mostly living in low socio-economic conditions. Numerous studies have been conducted over the past 10 years to compare the different techniques for T. trichiura eggs detection. Our study provides the first geometric morphometric analysis for the specific detection of eggs of Trichuris sp. isolated from stools of macaque (M. sylvanus), colobus (C. g. kikuyensis), grivets (C. aethiops) and the Brazza's monkey (C. neglectus) from zoos in Spain. Principal Component Analysis (PCA) arises as an efficient method to determine Trichuris spp. eggs. The selected measurements to be included in the PCA were pr…
Comparative infectivity of Fasciola hepatica metacercariae from isolates of the main and secondary reservoir animal host species in the Bolivian Altiplano high human endemic region.
Fascioliasis due to Fasciola hepatica (Linnaeus, 1758) is an endemic disease on the Northern Bolivian Altiplano, where human prevalences and intensities are the highest known, sheep and cattle are the main reservoir hosts, and pigs and donkeys the secondary ones. Investigations were carried out to study the viability of metacercariae experimentally obtained from eggs shed by naturally infected Altiplanic sheep, cattle, pigs and donkeys. A total of 157 Wistar rats were infected with doses of 5, 10, 20 and 150 metacercariae. Metacercariae aged for different number of weeks were used to analyse the influence of age on their viability. The number of worms successfully developed in each rat was …
High risk of bacterobilia in advanced experimental chronic fasciolosis
Fasciolosis is recognized as an important human disease. Wistar rats experimentally infected with Fasciola hepatica were examined using data obtained in the advanced chronic state of the disease (200, 300 and 400 days post-infection, dpi). Pigment stones (PS) and bile specimens were collected. The same procedure was applied in control rats. Liver tests were determined using stored serum samples. Bacteriological bile culture revealed viable bacteria (Escherichia coli, 45% of cases, Enterococcus faecalis, 45% and Klebsiella pneumoniae, 10%). The presence of bacterobilia was associated with liver serum enzymes, including aspartate aminotransferase (AST or SGOT), alanine aminotransferase (ALT o…
Differentiation of Trichuris species using a morphometric approach
Trichuris trichiura is a nematode considered as the whipworm present in humans and primates. The systematics of the genus Trichuris is complex. Morphological studies of Trichuris isolated from primates and humans conclude that the species infecting these hosts is the same. Furthermore, numerous molecular studies have been carried out so far to discriminate parasite species from humans and Non-Human Primates using molecular techniques, but these studies were not performed in combination with a parallel morphological study. The hypothesised existence of more species of Trichuris in primates opens the possibility to revise the zoonotic potential and host specificity of T. trichiura and other p…
Chapter 2 Fasciola, Lymnaeids and Human Fascioliasis, with a Global Overview on Disease Transmission, Epidemiology, Evolutionary Genetics, Molecular Epidemiology and Control
Abstract Fascioliasis, caused by liver fluke species of the genus Fasciola, has always been well recognized because of its high veterinary impact but it has been among the most neglected diseases for decades with regard to human infection. However, the increasing importance of human fascioliasis worldwide has re‐launched interest in fascioliasis. From the 1990s, many new concepts have been developed regarding human fascioliasis and these have furnished a new baseline for the human disease that is very different to a simple extrapolation from fascioliasis in livestock. Studies have shown that human fascioliasis presents marked heterogeneity, including different epidemiological situations and…
Administration of triclabendazole is safe and effective in controlling fascioliasis in an endemic community of the Bolivian Altiplano.
Background The Bolivian northern Altiplano is characterized by a high prevalence of Fasciola hepatica infection. In order to assess the feasibility, safety and efficacy of large-scale administration of triclabendazole as an appropriate public health measure to control morbidity associated with fascioliasis, a pilot intervention was implemented in 2008. Materials and Methods Schoolchildren from an endemic community were screened for fascioliasis and treated with a single administration of triclabendazole (10 mg/kg). Interviews to assess the occurrence of adverse events were conducted on treatment day, one week later, and one month after treatment. Further parasitological screenings were perf…
First Data on the Helminth Community of the Smallest Living Mammal on Earth, the Etruscan Pygmy Shrew, Suncus etruscus (Savi, 1822) (Eulipotyphla: Soricidae)
Suncus etruscus is the smallest living mammal on Earth by mass. Most adults weigh 1.8–3 g with a body length of 35–48 mm. Catching it in small mammal traps in nature is extremely difficult due to its minute size, and therefore special trapping methods must be used. We had the unique opportunity of studying, for the first time, the helminth parasites of 166 individuals of S. etruscus, part of the largest collection in the world, which belonged to the French scientist Dr Roger Fons (1942–2016). A total of 150 individuals were captured in the Banyuls-Cerbère area (France) and 16 in the island of Corsica (France). We found seven helminth species, specifically, the cestodes Joyeuxiella pasqualei…
Correlation between egg-shedding and uterus development in Fasciola hepatica human and animal isolates: applied implications
The emission of Fasciola hepatica eggs in faeces is usually subject to oscillations along time in animals as well as humans. Thus, looking for alternative biological markers reflecting eggs shed per gram of faeces (epg) with lower oscillations may be useful. This study analyzes the possible relationship between liver-fluke uterus area and epg. Uterus area (UA) development of adult F. hepatica obtained at different days post infection (dpi) in a Wistar rat model with isolates obtained from cattle, sheep, pigs and humans from the endemic human fascioliasis zone of the Northern Bolivian Altiplano was analyzed and compared with the number of eggs shed per gram of faeces as obtained through the …
Nuevas perspectivas sobre la detección de pediculosis activa en escolares del sur de Brasil
The present study aims to analyze the prevalence and risk factors of active pediculosis and to compare the efficacy and sensitivity of the vacuum method with the comb method and the visual inspection with a magnifying glass in order to determine the best methodology to detect active pediculosis among schoolchildren from Paraná state. Each child was examined by the three methods in sequence and a playful activity was introduced to increase the children likelihood to participate in the study. Additionally, hair characteristics and other risk factors as sex, age, and area of living were take into consideration to measure epidemiological aspects. From a total of 358 schoolchildren from southern…
DNA Multi-Marker Genotyping and CIAS Morphometric Phenotyping of Fasciola gigantica-Sized Flukes from Ecuador, with an Analysis of the Radix Absence in the New World and the Evolutionary Lymnaeid Snail Vector Filter
Simple Summary Fasciolid flukes collected from sheep and cattle in Ecuador showed a high diversity in DNA sequences whose analyses indicated introductions from South America, European and North American countries. These results agree with the numerous livestock importations performed by Ecuador. Abnormally big-sized liver flukes were found in Ecuadorian sheep. The morphometric phenotypic CIAS study showed that its size maximum and mean very pronouncedly and significantly surpassed those of the Fasciola hepatica populations from South America and Spain and proved to be intermediate between standard F. hepatica and F. gigantica populations. Such a feature is only known in intermediate fasciol…
Fasciola hepatica development in the experimentally infected black rat Rattus rattus
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 …
Crowding effect on adult growth, pre-patent period and egg shedding of Fasciola hepatica
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…
Phenotypic analysis of adults and eggs of Fasciola hepatica by computer image analysis system
AbstractKnowledge of the morphological phenotypes of the liver fluke Fasciola hepatica (Trematoda: Digenea) is analysed. The influence of parasite age on its dimensions, the adult fluke growth model, variation in a biometric variable versus time, and variation in a biometric variable versus another biometric variable (allometric model) are revised. The most useful allometric model appears to be (y2m]#x2212;y2)/y2=c [(y1m−y1)/y1]b, where y1=body area or body length, y2=one of the measurements analysed, y1m, y2m=maximum values towards which y1 and y2, respectively, tend, and c, b=constants. A method based on material standardization, the measurement proposal and allometric analysis is detaile…
Scalp microbiota alterations in children with pediculosis.
Pediculosis is a disease caused by the insect Pediculus humanus capitis that mainly occurs in childhood. A comparative study was carried out evaluating groups of schoolchildren with (group A) and without pediculosis (group B) to analyse the characteristics of the scalp microbiota. Samples were collected by swab using Stuart transport medium and incubate in Sabouraud dextrose agar with tetracycline to analyse the fungal microbiota and in blood agar to assess the bacterial microbiota. The isolates identity was confirmed by sequencing of the 16S and 18S regions of the ribosomal DNA gene for bacteria and fungi, respectively. The analysis of the 186 isolates led to the identification of 35 bacte…
Fascioliasis and other plant-borne trematode zoonoses
Fascioliasis and other food-borne trematodiases are included in the list of important helminthiases with a great impact on human development. Six plant-borne trematode species have been found to affect humans: Fasciola hepatica, Fasciola gigantica and Fasciolopsis buski (Fasciolidae), Gastrodiscoides hominis (Gastrodiscidae), Watsonius watsoni and Fischoederius elongatus (Paramphistomidae). Whereas F. hepatica and F. gigantica are hepatic, the other four species are intestinal parasites. The fasciolids and the gastrodiscid cause important zoonoses distributed throughout many countries, while W. watsoni and F. elongatus have been only accidentally detected in humans. Present climate and glob…
First phenotypic description of Fasciola hepatica/Fasciola gigantica intermediate forms from the human endemic area of the Nile Delta, Egypt.
Fasciola gigantica is the main fasciolid species in Africa; however, F. hepatica and F. gigantica overlap in some countries. Egypt deserves mentioning because of the emerging situation of human fascioliasis in the Nile Delta area. The morphometric characteristics of fasciolid adults infecting the main livestock species present in the Nile Delta human endemic area are analyzed through a computer image analysis system (CIAS) on the basis of standardized measurements known to be useful for the differentiation of both fasciolid species. This is the first time that such a study is performed in an African country and, therefore, the results are compared to (i) F. hepatica (European Mediterranean …
Fascioliasis and Intestinal Parasitoses Affecting Schoolchildren in Atlixco, Puebla State, Mexico: Epidemiology and Treatment with Nitazoxanide
Background The Atlixco municipality, Puebla State, at a mean altitude of 1840 m, was selected for a study of Fasciola hepatica infection in schoolchildren in Mexico. This area presents permanent water collections continuously receiving thaw water from Popocatepetl volcano (5426 m altitude) through the community supply channels, conforming an epidemiological scenario similar to those known in hyperendemic areas of Andean countries. Methodology and Findings A total of 865 6–14 year-old schoolchildren were analyzed with FasciDIG coproantigen test and Lumbreras rapid sedimentation technique, and quantitatively assessed with Kato-Katz. Fascioliasis prevalences ranged 2.94–13.33% according to loc…
Risk of gallstone disease in advanced chronic phase of fascioliasis: an experimental study in a rat model.
In Wistar rats experimentally infected with Fasciola hepatica, the association between time of infection, number of flukes, rat weight, and serum lipid levels and the risk of developing pigment stones in the main bile duct was examined using data obtained at 100, 200, 300, 400, and 500 days postinfection. Gallstone presence increased with infection time. The relative risk of gallstone disease increased when the number of flukes per rat and rat weight increased. The presence of gallstones was associated with serum high-density lipoproteins and triglyceride levels. In a multivariate analysis, the association between gallstones and rat weight disappeared after adjustment for serum lipids. The …
Hyperendemic fascioliasis associated with schistosomiasis in villages in the Nile Delta of Egypt.
Coprologic surveys were carried out in villages of the Behera Governorate in the Nile Delta region of Egypt to characterize the epidemiologic features of human fascioliasis caused by Fasciola hepatica and F. gigantica in this lowland endemic area by comparison with fascioliasis caused by only F. hepatica in areas hyperendemic for human disease in the Andean highlands of South America. The fascioliasis prevalences detected (range = 5.2-19.0%, mean = 12.8%) are the highest obtained in Egypt. The comparison with previous results suggests that in the Nile Delta, fascioliasis is spreading from an original situation of sporadic human cases in well-known endemic foci for animal disease to an endem…
Description deHymenolepis cerberensisn. sp. (Cestoda : Hymenolepididae) et premières considérations générales sur la faune de Cestodes parasites de la Pachyure étrusque,Suncus etruscus(Savi, 1822) (Insectivora : Soricidae)
Description et differenciation de l’adulte de Hymenolepis cerberensis n. sp. (Cestoda : Hymenolepididae), parasite intestinal de la Musaraigne etrusque, Suncus etruscus (Savi, 1822) (Insectivora : Soricidae : Crocidurinae) capturee sur les communes de Banyuls-sur-Mer et Cerbere (Pyrenees-Orientales, France). La nouvelle espece est caracterisee par la taille des individus gravides et la presence de 18-21 crochets rostraux de 18,5-20 µm de longueur et de filaments autour de l’embryophore. La composition generale de la faune de Cyclophyllidea parasites de S. etruscus est analysee. Il s’agit de trois Hymenolepis peu specialises a scolex du meme type et d’un Pseudhymenolepis , avec absence d’esp…
Administration of Triclabendazole Is Safe and Effective in Controlling Fascioliasis in an Endemic Community of the Bolivian Altiplano
Background Emergence of human fascioliasis prompted a worldwide control initiative including a pilot study in a few countries. Two hyperendemic areas were chosen: Huacullani, Northern Altiplano, Bolivia, representing the Altiplanic transmission pattern with high prevalences and intensities; Cajamarca valley, Peru, representing the valley pattern with high prevalences but low intensities. Coprological sample collection, transport and study procedures were analyzed to improve individual diagnosis and subsequent treatments and surveillance activities. Therefore, a coproantigen-detection technique (MM3-COPRO ELISA) was evaluated, using classical techniques for egg detection for comparison. Meth…
Diagnosis of human fascioliasis by stool and blood techniques: update for the present global scenario
SUMMARYBefore the 1990s, human fascioliasis diagnosis focused on individual patients in hospitals or health centres. Case reports were mainly from developed countries and usually concerned isolated human infection in animal endemic areas. From the mid-1990s onwards, due to the progressive description of human endemic areas and human infection reports in developing countries, but also new knowledge on clinical manifestations and pathology, new situations, hitherto neglected, entered in the global scenario. Human fascioliasis has proved to be pronouncedly more heterogeneous than previously thought, including different transmission patterns and epidemiological situations. Stool and blood techn…
The genus Scaphiostomum Braun, 1901 (Trematoda: Brachylaimidae): A systematic review and description of Scaphiostomum palaearcticum n. sp.
A systematic review of the genus Scaphiostomum Braun, 1901 (Trematoda: Brachylaimidae) is presented. Its diagnosis is emended and its position within the subfamily Brachylaiminae Joyeux & Foley, 1930 is established. The subfamily Scaphiostominae Yamaguti, 1958 is considered a synonym of the Brachy-laiminae. Scaphiostomum comprises the following species: S. illatabile Braun, 1901 (type species) from birds in South America, S. pancreaticum McIntosh, 1934 and S. microti (Kruidenier & Gallicchio, 1959) n. comb., both from rodents in North America, and S. palaearcticum n. sp. from rodents in the Balearic Islands (Spain). Scaphiostomum sp. of Lim, 1967 from rodents in Malaysia probably constitute…
Plant-Borne Trematode Zoonoses: Fascioliasis and Fasciolopsiasis
There are six plant-borne trematode species known affecting humans: Fasciola hepatica, F. gigantica, and Fasciolopsis buski (Fasciolidae), Gastrodiscoides hominis (Gastrodiscidae), Watsonius watsoni, and Fischoederius elongatus (Paramphistomidae). Whereas F. hepatica and F. gigantica are hepatic, the other four species are intestinal parasites.
Aedes albopictus diversity and relationships in south-western Europe and Brazil by rDNA/mtDNA and phenotypic analyses: ITS-2, a useful marker for spread studies
AbstractBackgroundAedes albopictusis a very invasive mosquito, which has recently colonized tropical and temperate regions worldwide. Of concern is its role in the spread of emerging or re-emerging mosquito-borne diseases.Ae. albopictusfrom south-western Europe and Brazil were studied to infer genetic and phenetic diversity at intra-individual, intra-population and inter-population levels, and to analyse its spread.MethodsGenotyping was made by rDNA 5.8S-ITS-2 and mtDNAcox1 sequencing to assess haplotype and nucleotide diversity, genetic distances and phylogenetic networks. Male and female phenotyping included combined landmark-and outlined-based geometric morphometrics of wing size and sha…
Efectos del cambio climático en las helmintiasis animales y zoonóticas
Current knowledge of animal and zoonotic helminthiases in which effects of climate change have been detected is reviewed. Climate variables are able to affect the prevalence, intensity and geographical distribution of helminths, directly influencing free-living larval stages and indirectly influencing mainly invertebrate, but also vertebrate, hosts. The impact of climate change appears to be more pronounced in trematodes, and is mainly shown by increased cercarial production and emergence associated with global warming. Fascioliasis, schistosomiasis (S. japonicum) and cercarial dermatitis caused by avian schistosomes have been the focus of study. Alveolar echinococcosis is currently the onl…
Fasciola hepatica : lithogenic capacity in experimentally infested rats and chemical determination of the main stone components
A study was done of the possible association between the development of common bile-duct stones and the presence of worms in rats experimentally infected with Fasciola hepatica. A total of 157 rats were individually infected with 20 metacercariae, and another 40 animals served as controls. The rats were dissected at 100, 200, 300, and 400 days postinfection (p.i.). A significant association was observed between the observation of stones and the presence of F. hepatica adults. The global frequency of bile-duct lithiasis in the parasitized rats was 22%, with a significantly lower incidence being observed in the younger group (100 days p.i.). Different analytical techniques were used to determ…
MM3-ELISA evaluation of coproantigen release and serum antibody production in sheep experimentally infected with Fasciola hepatica and F. gigantica.
During an experimental infection of sheep with Fasciola hepatica or F. gigantica, MM3-SERO and MM3-COPRO ELISA tests were applied to compare the kinetics of antibody production and coproantigen release between the 2nd and 32nd week post-infection (wpi). The Kato-Katz technique was used to measure the kinetics of egg shedding by both Fasciola species (eggs per gram of feces, epg). The kinetics of IgG antibodies for all sheep infected with F. hepatica and F. gigantica followed a similar pattern. Optical density (OD) increased rapidly between the 4th until the 12th wpi, when the highest values were reached and then decreased slowly until the 32nd wpi. Coproantigen levels increased above the cu…
Neurological and Ocular Fascioliasis in Humans
Fascioliasis is a food-borne parasitic disease caused by the trematode species Fasciola hepatica, distributed worldwide, and Fasciola gigantica, restricted to given regions of Africa and Asia. This disease in humans shows an increasing importance, which relies on its recent widespread emergence related to climate and global changes and also on its pathogenicity in the invasive, biliary, and advanced chronic phases in the human endemic areas, mainly of developing countries. In spite of the large neurological affection capacity of Fasciola, this important pathogenic aspect of the disease has been pronouncedly overlooked in the past decades and has not even appear within the numerous reviews o…
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
Simple Summary The infection by the liver fluke Fasciola hepatica in South American camelids, mainly llamas and alpacas, has been the focus of many studies. However, their capacity to participate in the transmission of the disease and their potential reservoir role in human or animal endemic areas have never been studied. Therefore, all development stages of an isolate from Argentine llama of the high Andean plateau have been experimentally investigated, from egg embryogenesis to metacercarial infectivity, by using the vector snail Galba truncatula from the high altitude Bolivian Altiplano human hyperendemic area. Although eggs shed by llamas may successfully develop until the adult stage i…
Climate change effects on trematodiases, with emphasis on zoonotic fascioliasis and schistosomiasis.
The capacity of climatic conditions to modulate the extent and intensity of parasitism is well known since long ago. Concerning helminths, among the numerous environmental modifications giving rise to changes in infections, climate variables appear as those showing a greater influence, so that climate change may be expected to have an important impact on the diseases they cause. However, the confirmation of the impact of climate change on helminthiases has been reached very recently. Only shortly before, helminthiases were still noted as infectious diseases scarcely affected by climate change, when compared to diseases caused by microorganisms in general (viruses, bacteriae, protozoans). Th…
Numerous Fasciola plasminogen-binding proteins may underlie blood-brain barrier leakage and explain neurological disorder complexity and heterogeneity in the acute and chronic phases of human fascioliasis
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Comparison of adult liver flukes from highland and lowland populations of Bolivian and Spanish sheep.
A morphological study of adult liver flukes and eggs from sheep in a human fascioliasis endemic zone in the Northern Bolivian Altiplano showed that they belong to the species Fasciola hepatica. An exhaustive morphometric comparison with a F. hepatica population from Spanish sheep was made using image analysis and an allometric model: (y2m - y2)]#x002F;y2 = c[(y1m - y1)/y1]b, where y1 = body surface or body length, y2 = one of the measurements analysed, y1m, y2m = maximum values towards which y1 and y2 respectively tend, and c, b = constants. Only slight allometric differences in worms were observed despite the geographic distance between both Spanish and Bolivian sheep populations and the v…
Phenotypic analysis of adults of Fasciola hepatica, Fasciola gigantica and intermediate forms from the endemic region of Gilan, Iran.
Fascioliasis is an important human and animal disease caused by Fasciola hepatica and Fasciola gigantica. In Iran, the distribution of these two species overlaps in most areas, including the northern human endemic province of Gilan where both fasciolids are simultaneously found in individual cattle and buffaloes. A phenotypic study of fasciolid adult flukes from naturally infected bovines from Gilan was carried out by means of an exhaustive morphometric analysis using traditional microscopic measurements and an allometric model. The Iranian fasciolids were compared to F. hepatica and F. gigantica standard populations, i.e. from geographical areas where both species do not co-exist (Bolivia …