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1.
Adv Exp Med Biol ; 1454: 75-105, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39008264

RESUMEN

Schistosomiasis is a major cause of morbidity in the world and almost 800 million people worldwide are at risk for schistosomiasis; it is second only to malaria as a major infectious disease. Globally, it is estimated that the disease affects more than 250 million people in 78 countries of the world and is responsible for some 280,000-500,000 deaths each year. The three major schistosomes infecting humans are Schistosoma mansoni, S. japonicum, and S. haematobium. This chapter covers a wide range of aspects of schistosomiasis, including basic biology of the parasites, epidemiology, immunopathology, treatment, control, vaccines, and genomics/proteomics. In this chapter, the reader will understand the significant toll this disease takes in terms of mortality and morbidity. A description of the various life stages of schistosomes is presented, which will be informative for both those unfamiliar with the disease and experienced scientists. Clinical and public health aspects are addressed that cover acute and chronic disease, diagnosis, current treatment regimens and alternative drugs, and schistosomiasis control programs. A brief overview of genomics and proteomics is included that details recent advances in the field that will help scientists investigate the molecular biology of schistosomes. The reader will take away an appreciation for general aspects of schistosomiasis and the current research advances.


Asunto(s)
Esquistosomiasis , Humanos , Animales , Esquistosomiasis/parasitología , Esquistosomiasis/epidemiología , Esquistosomiasis/diagnóstico , Schistosoma/fisiología , Schistosoma/genética , Schistosoma/patogenicidad , Proteómica/métodos , Estadios del Ciclo de Vida , Genómica/métodos
2.
Parasitol Res ; 120(5): 1755-1770, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33687566

RESUMEN

Cercarial emission of schistosomes is a determinant in the transmission to the definitive host and constitutes a good marker to identify which definitive host is responsible for transmission, mainly in introgressive hybridization situations. Our goal was to test the hypothesis that micro-mammals play a role in Schistosoma haematobium, S. bovis, and/or S. haematobium x S. bovis transmission. Small mammal sampling was conducted in seven semi-lacustrine villages of southern Benin. Among the 62 animals trapped, 50 individuals were investigated for Schistosoma adults and eggs: 37 Rattus rattus, 3 Rattus norvegicus, 9 Mastomys natalensis, and 1 Crocidura olivieri. Schistosoma adults were found in four R. rattus and two M. natalensis, with a local prevalence reaching 80% and 50%, respectively. Two cercarial chronotypes were found from Bulinus globosus experimentally infected with miracidia extracted from naturally infected M. natalensis: a late diurnal and nocturnal chronotype, and an early diurnal, late diurnal, and nocturnal chronotype. The cytochrome C oxidase subunit I mtDNA gene of the collected schistosomes (adults, miracidia, and cercariae) belonged to the S. bovis clade. Eleven internal transcribed spacer rDNA profiles were found; four belonged to S. bovis and seven to S. haematobium x S. bovis. These molecular results together with the observed multi-peak chronotypes add M. natalensis as a new host implicated in S. haematobium x S. bovis transmission. We discuss the origin of the new chronotypes which have become more complex with the appearance of several peaks in a 24-h day. We also discuss how the new populations of offspring may optimize intra-host ecological niche, host spectrum, and transmission time period.


Asunto(s)
Introgresión Genética , Murinae/parasitología , Schistosoma haematobium/fisiología , Schistosoma/fisiología , Esquistosomiasis/parasitología , Esquistosomiasis/transmisión , Animales , Benin , Bulinus/parasitología , Cercarias/genética , ADN Mitocondrial , ADN Ribosómico , Ecosistema , Femenino , Interacciones Huésped-Parásitos , Masculino , Tipificación Molecular , Prevalencia , Ratas , Schistosoma/genética , Schistosoma haematobium/genética , Esquistosomiasis Urinaria/parasitología , Esquistosomiasis Urinaria/transmisión , Musarañas/parasitología
3.
Epidemiol Infect ; 148: e152, 2020 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-32605678

RESUMEN

A new developed spatially targeted mollusciciding technology for snail control was utilised in a research site. This study aims to analyse whether this technology can achieve rational effectiveness compared with the routine method. Snail density was monitored every spring and autumn from 2010 to 2017 at the research site and routine mollusciciding for snail control was then performed. After snail density monitoring in spring 2018, spatially targeted mollusciciding technology was adopted. Log-linear regression and nonlinear regression models were used for snail density prediction in autumn 2018 and the predicted value was compared with the actual snail density in autumn 2018 to verify the effectiveness of the spatially targeted mollusciciding. Monitoring results showed that overall snail density in the research site decreased from 2010 to 2018. The monitored snail density in autumn 2018 was 0.014/0.1 m2. Predicted by the log-linear regression model, the snail density in autumn 2018 would be 0.028 (95% CI 0.11-0.072)/0.1 m2. Predicted by the nonlinear regression model, the snail density growth in autumn 2018 in contrast to spring 2018 would be 79.79% (95% CI 54.81%-104.77%) and the actual value was 55.56%. Therefore, the effectiveness of the first application of spatially targeted mollusciciding was acceptable. However, the validation of its sustainable effectiveness still needs a replicated study comparing areas where targeted and untargeted methods are applied simultaneously and both snail abundance and human infection are monitored.


Asunto(s)
Moluscocidas/farmacología , Caracoles/efectos de los fármacos , Animales , China , Interacciones Huésped-Parásitos , Modelos Lineales , Control de Plagas , Densidad de Población , Ríos , Schistosoma/fisiología , Caracoles/parasitología
4.
Parasitology ; 147(12): 1369-1374, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-32660659

RESUMEN

Trematode transmission in aquatic habitats from molluscan intermediate host to vertebrate or invertebrate target host is typically undertaken by a free-living stage known as cercariae. Active locomotion by cercariae is a key aspect of the transmission process with the swimming speed potentially contributing to infection success. Individual cercarial species swim at different speeds but the significance of this to infection potential has not been determined. This study, using data from the scientific literature, investigates the role of swimming speed in relation to cercarial morphology, host-searching strategies and target host species. Larger cercariae swim faster than smaller ones with tail length being the principal factor controlling locomotion rates. Different cercarial morphotypes swim at different speeds, in particular, furcocercariae, with the exception of the schistosomes, being faster swimmers than mono-tailed cercariae. Host-searching behaviour has a significant influence on swimming speeds with 'active-searching' strategies swimming slower than those adopting 'active-waiting' or 'prey mimcry' strategies. Vertebrate-infecting cercariae swim faster than those infecting invertebrates with species targeting fish demonstrating the highest locomotion rates and those targeting arthropods the slowest speeds. The adaptions of individual cercarial swimming speeds to biological variables and their interactions with the physical processes of aquatic habitats are discussed.


Asunto(s)
Cercarias/fisiología , Trematodos/fisiología , Infecciones por Trematodos/transmisión , Animales , Organismos Acuáticos/parasitología , Organismos Acuáticos/fisiología , Artrópodos/parasitología , Conducta , Peces/parasitología , Invertebrados/parasitología , Schistosoma/fisiología , Natación/fisiología , Vertebrados/parasitología
5.
Parasitology ; 147(3): 287-294, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-31727202

RESUMEN

Schistosomiasis is a neglected tropical disease, though it is highly prevalent in many parts of sub-Saharan Africa. While Schistosoma haematobium-bovis hybrids have been reported in West Africa, no data about Schistosoma hybrids in humans are available from Côte d'Ivoire. This study aimed to identify and quantify S. haematobium-bovis hybrids among schoolchildren in four localities of Côte d'Ivoire. Urine samples were collected and examined by filtration to detect Schistosoma eggs. Eggs were hatched and 503 miracidia were individually collected and stored on Whatman® FTA cards for molecular analysis. Individual miracidia were molecularly characterized by analysis of mitochondrial cox1 and nuclear internal transcribed spacer 2 (ITS 2) DNA regions. A mitochondrial cox1-based diagnostic polymerase chain reaction was performed on 459 miracidia, with 239 (52.1%) exhibiting the typical band for S. haematobium and 220 (47.9%) the S. bovis band. The cox1 and ITS 2 amplicons were Sanger sequenced from 40 randomly selected miracidia to confirm species and hybrids status. Among the 33 cox1 sequences analysed, we identified 15 S. haematobium sequences (45.5%) belonging to seven haplotypes and 18 S. bovis sequences (54.5%) belonging to 12 haplotypes. Of 40 ITS 2 sequences analysed, 31 (77.5%) were assigned to pure S. haematobium, four (10.0%) to pure S. bovis and five (12.5%) to S. haematobium-bovis hybrids. Our findings suggest that S. haematobium-bovis hybrids are common in Côte d'Ivoire. Hence, intense prospection of domestic and wild animals is warranted to determine whether zoonotic transmission occurs.


Asunto(s)
Hibridación Genética , Schistosoma/fisiología , Esquistosomiasis/epidemiología , Adolescente , Animales , Niño , Preescolar , Côte d'Ivoire/epidemiología , ADN de Helmintos/análisis , ADN Intergénico/análisis , Complejo IV de Transporte de Electrones/análisis , Proteínas del Helminto/análisis , Humanos , Proteínas Mitocondriales/análisis , Prevalencia , Schistosoma/genética , Schistosoma haematobium/genética , Schistosoma haematobium/fisiología , Esquistosomiasis/parasitología
6.
Adv Exp Med Biol ; 1154: 45-70, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31297759

RESUMEN

Schistosomiasis is a major cause of morbidity in the world; it is second only to malaria as a major infectious disease. Globally, it is estimated that the disease affects over 250 million people in 78 countries of the world and is responsible for some 280,000 deaths each year. The three major schistosomes infecting humans are Schistosoma mansoni, S. japonicum, and S. haematobium. This chapter covers a wide range of aspects of schistosomiasis, including basic biology of the parasites, epidemiology, immunopathology, treatment, control, vaccines, and genomics/proteomics. In this chapter, the reader will understand the significant toll this disease takes in terms of mortality and morbidity. A description of the various life stages of schistosomes is presented, which will be informative for both those unfamiliar with the disease and experienced scientists. Clinical and public health aspects are addressed that cover acute and chronic disease, diagnosis, current treatment regimens and alternative drugs, and schistosomiasis control programs. A brief overview of genomics and proteomics is included that details recent advances in the field that will help scientists investigate the molecular biology of schistosomes. The reader will take away an appreciation for general aspects of schistosomiasis and research advances.


Asunto(s)
Esquistosomiasis , Animales , Humanos , Investigación/tendencias , Schistosoma/fisiología , Esquistosomiasis/tratamiento farmacológico , Esquistosomiasis/parasitología , Esquistosomiasis/patología , Esquistosomiasis/prevención & control
7.
Proc Natl Acad Sci U S A ; 112(31): 9650-5, 2015 Aug 04.
Artículo en Inglés | MEDLINE | ID: mdl-26195752

RESUMEN

Eliminating human parasitic disease often requires interrupting complex transmission pathways. Even when drugs to treat people are available, disease control can be difficult if the parasite can persist in nonhuman hosts. Here, we show that restoration of a natural predator of a parasite's intermediate hosts may enhance drug-based schistosomiasis control. Our study site was the Senegal River Basin, where villagers suffered a massive outbreak and persistent epidemic after the 1986 completion of the Diama Dam. The dam blocked the annual migration of native river prawns (Macrobrachium vollenhoveni) that are voracious predators of the snail intermediate hosts for schistosomiasis. We tested schistosomiasis control by reintroduced river prawns in a before-after-control-impact field experiment that tracked parasitism in snails and people at two matched villages after prawns were stocked at one village's river access point. The abundance of infected snails was 80% lower at that village, presumably because prawn predation reduced the abundance and average life span of latently infected snails. As expected from a reduction in infected snails, human schistosomiasis prevalence was 18 ± 5% lower and egg burden was 50 ± 8% lower at the prawn-stocking village compared with the control village. In a mathematical model of the system, stocking prawns, coupled with infrequent mass drug treatment, eliminates schistosomiasis from high-transmission sites. We conclude that restoring river prawns could be a novel contribution to controlling, or eliminating, schistosomiasis.


Asunto(s)
Biomphalaria/parasitología , Palaemonidae/fisiología , Ríos , Esquistosomiasis/parasitología , Esquistosomiasis/transmisión , Adolescente , Adulto , Animales , Niño , Preescolar , Femenino , Interacciones Huésped-Parásitos , Humanos , Masculino , Persona de Mediana Edad , Modelos Biológicos , Conducta Predatoria , Prevalencia , Schistosoma/fisiología , Esquistosomiasis/epidemiología , Adulto Joven
8.
J Helminthol ; 94: e21, 2018 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-30526698

RESUMEN

Schistosomiasis or bilharzia is a widespread parasitic disease caused by blood flukes of the genus Schistosoma. Some factors have been investigated previously regarding their effect on the pathophysiological mechanism of human schistosomiasis, but the possible influence of the ABO blood group on the severity of Schistosoma infection has been the most promising. Hence, we performed a systematic review and meta-analysis to further investigate the association of the ABO blood group with schistosomiasis susceptibility. Selected publications were retrieved from PubMed up to 21 August 2018, for related studies written in English. Number of cases (with schistosomiasis) and controls (without schistosomiasis) were extracted across all ABO blood types. Odds ratios (OR) and 95% confidence intervals (CI) were computed, pooled and interpreted. Subgroup analysis by the species of Schistosoma infecting the population and the participants' ethnicity was also performed. The overall analysis revealed heterogeneity in the outcomes, which warranted the identification of the cause using the Galbraith plot. Post-outlier outcomes of the pooled ORs show that individuals who are not blood type O are more susceptible (OR: 1.40; 95% CI: 1.17-1.67; PA < 0.001) to schistosomiasis than those who are blood type O (OR: 0.71; 95% CI: 0.60-0.85; PA < 0.001). Subgroup analysis yielded the same observations regardless of the species of schistosome and the ethnicity of the participants. Results of this meta-analysis suggest that individuals who are blood type B and A are more susceptible to schistosomiasis than those who are blood type O. However, more studies are needed to confirm our claims.


Asunto(s)
Sistema del Grupo Sanguíneo ABO/inmunología , Schistosoma/fisiología , Esquistosomiasis/parasitología , Sistema del Grupo Sanguíneo ABO/genética , Animales , Tipificación y Pruebas Cruzadas Sanguíneas , Femenino , Humanos , Masculino , Schistosoma/genética , Schistosoma/aislamiento & purificación , Esquistosomiasis/genética , Esquistosomiasis/inmunología
9.
Acta Vet Hung ; 66(4): 587-606, 2018 12.
Artículo en Inglés | MEDLINE | ID: mdl-30580539

RESUMEN

Additional geographical distribution of the Central European populations of Schistosoma turkestanicum and the detectability of their eggs in droppings were investigated in red deer samples, because this rare species had previously been shown only in a single Hungarian habitat. Samples from visceral organs, intestinal contents, and droppings on the ground from 11 hunting areas of Hungary were investigated to find a new presence of this fluke. Close to the first site of detection in the Gemenc forest another habitat along the southern border of the country was found where the parasite lives in red deer. Therefore, it is possible that the worm also occurs in neighbouring Serbia or Croatia. Schistosoma turkestanicum causes a low-intensity infection in red deer and this host sheds low amounts of eggs, therefore the eggs are difficult to detect. Droppings were cleared by sedimentation, filtered by sieve screening and then the eggs were flotated using solutions with an increasing density of 1200 g/L, 1300 g/L, 1350 g/L, and 1400 g/L while they were being stained red with acid fuchsin. Eggs in fresh faeces can be most efficiently separated from plant fibres using a flotation solution of 1350 g/L density, but in some cases eggs in old dung can be detected using a solution of a specific gravity lower or higher than that. By combining the advantages of the three concentration processes, eggs of S. turkestanicum, which are more recognisable by the red stain, can be found in samples in which they are present at a density lower than 1/g.


Asunto(s)
Ciervos , Heces/parasitología , Schistosoma/fisiología , Esquistosomiasis/veterinaria , Animales , Geografía , Hungría , Esquistosomiasis/parasitología
10.
J Theor Biol ; 432: 87-99, 2017 11 07.
Artículo en Inglés | MEDLINE | ID: mdl-28823529

RESUMEN

Simple models of disease propagation often disregard the effects of transmission heterogeneity on the ecological and epidemiological dynamics associated with host-parasite interactions. However, for some diseases like schistosomiasis, a widespread parasitic infection caused by Schistosoma worms, accounting for heterogeneity is crucial to both characterize long-term dynamics and evaluate opportunities for disease control. Elaborating on the classic Macdonald model for macroparasite transmission, we analyze families of models including explicit descriptions of heterogeneity related to differential transmission risk within a community, water contact patterns, the distribution of the snail host population, human mobility, and the seasonal fluctuations of the environment. Through simple numerical examples, we show that heterogeneous multigroup communities may be more prone to schistosomiasis than homogeneous ones, that the availability of multiple water sources can hinder parasite transmission, and that both spatial and temporal heterogeneities may have nontrivial implications for disease endemicity. Finally, we discuss the implications of heterogeneity for disease control. Although focused on schistosomiasis, results from this study may apply as well to other parasitic infections with complex transmission cycles, such as cysticercosis, dracunculiasis and fasciolosis.


Asunto(s)
Esquistosomiasis/transmisión , Animales , Enfermedades Endémicas , Humanos , Modelos Biológicos , Schistosoma/fisiología , Esquistosomiasis/epidemiología , Esquistosomiasis/parasitología , Factores de Tiempo
11.
Mol Cell Probes ; 31: 2-21, 2017 02.
Artículo en Inglés | MEDLINE | ID: mdl-27986555

RESUMEN

Schistosomiasis is a common disease in endemic areas of Sub-Saharan Africa, South America and Asia. It is rare in Europe, mainly imported from endemic countries due to travelling or human migration. Available methods for the diagnosis of schistosomiasis comprise microscopic, molecular and serological approaches, with the latter detecting antigens or antibodies associated with Schistosoma spp. infection. The serological approach is a valuable screening tool in low-endemicity settings and for travel medicine, though the interpretation of any diagnostic results requires knowledge of test characteristics and a patient's history. Specific antibody detection by most currently used assays is only possible in a relatively late stage of infection and does not allow for the differentiation of acute from previous infections for therapeutic control or the discrimination between persisting infection and re-infection. Throughout the last decades, new target antigens have been identified, and assays with improved performance and suitability for use in the field have been developed. For numerous assays, large-scale studies are still required to reliably characterise assay characteristics alone and in association with other available methods for the diagnosis of schistosomiasis. Apart from S. mansoni, S. haematobium and S. japonicum, for which most available tests were developed, other species of Schistosoma that occur less frequently need to be taken into account. This narrative review describes and critically discusses the results of published studies on the evaluation of serological assays that detect antibodies against different Schistosoma species of humans. It provides insights into the diagnostic performance and an overview of available assays and their suitability for large-scale use or individual diagnosis, and thus sets the scene for serological diagnosis of schistosomiasis and the interpretation of results.


Asunto(s)
Esquistosomiasis/sangre , Esquistosomiasis/diagnóstico , Serotipificación/métodos , Animales , Anticuerpos Antihelmínticos/inmunología , Antígenos Helmínticos/inmunología , Humanos , Schistosoma/inmunología , Schistosoma/fisiología , Esquistosomiasis/inmunología
12.
Parasitology ; 144(12): 1602-1612, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27363810

RESUMEN

Part of Robert T. Leiper's (1881-1969) lasting legacy in medical helminthology is grounded on his pioneering work on schistosomiasis (Bilharzia). Having undertaken many expeditions to the tropics, his fascination with parasite life cycles typically allowed him to devise simple preventive measures that curtailed transmission. Building on his formative work with others in Africa and Asia, and again in Egypt in 1915, he elucidated the life cycles of African schistosomes. His mandate, then commissioned by the British War Office, was to prevent and break transmission of this disease in British troops. This he did by raising standing orders based on simple water hygiene measures. Whilst feasible in military camp settings, today their routine implementation is sadly out of reach for millions of Africans living in poverty. Whilst we celebrate the centenary of Leiper's research we draw attention to some of his lesser known colleagues, then focus on schistosomiasis in Uganda discussing why expanded access to treatment with praziquantel is needed now. Looking to WHO 2020 targets for neglected tropical diseases, we introduce COUNTDOWN, an implementation research consortium funded by DFID, UK, which fosters the scale-up of interventions and confirm the current relevance of Leiper's original research.


Asunto(s)
Medicina Militar/historia , Enfermedades Desatendidas/historia , Esquistosomiasis/historia , Medicina Tropical/historia , África , Animales , Asia , Historia del Siglo XX , Humanos , Enfermedades Desatendidas/prevención & control , Schistosoma/fisiología , Esquistosomiasis/prevención & control , Escocia , Uganda
13.
Parasitol Res ; 116(3): 865-870, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28012027

RESUMEN

Nasal bird schistosomes can cause bilharziosis in birds and have the potential to cause swimmer's itch in humans. We determined the prevalence of bird schistosomes in 106 mallards (Anas plathyrhynchos) from 11 water sources in Germany from 2014. Dissections were performed focusing on parasitic infections of the neural system. Infections with Trichobilharzia regenti (Horák et al. 1998) were found in 21% of the birds (n = 22), whereas Bilharziella polonica (Kowalewski 1895) were found between the brain membranes (meninges) and the brain, in the spinal cord or in the intestine of 12% of the mallards (n = 13). No significant influence of sex, age, and body condition between infected and non-infected animals was observed. Our study provides the first description of B. polonica from the neural system of birds and provides an epidemiological understanding of a parasite of human health concern.


Asunto(s)
Enfermedades de las Aves/parasitología , Patos/parasitología , Sistema Nervioso/parasitología , Schistosoma/aislamiento & purificación , Schistosomatidae/aislamiento & purificación , Infecciones por Trematodos/veterinaria , Animales , Animales Salvajes/parasitología , Alemania , Humanos , Schistosoma/genética , Schistosoma/fisiología , Schistosomatidae/genética , Schistosomatidae/fisiología , Infecciones por Trematodos/parasitología
14.
PLoS Pathog ; 10(8): e1004246, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25121497

RESUMEN

Schistosomes are parasitic flatworms that infect >200 million people worldwide, causing the chronic, debilitating disease schistosomiasis. Unusual among parasitic helminths, the long-lived adult worms, continuously bathed in blood, take up nutrients directly across the body surface and also by ingestion of blood into the gut. Recent proteomic analyses of the body surface revealed the presence of hydrolytic enzymes, solute, and ion transporters, thus emphasising its metabolic credentials. Furthermore, definition of the molecular mechanisms for the uptake of selected metabolites (glucose, certain amino acids, and water) establishes it as a vital site of nutrient acquisition. Nevertheless, the amount of blood ingested into the gut per day is considerable: for males ∼100 nl; for the more actively feeding females ∼900 nl, >4 times body volume. Ingested erythrocytes are lysed as they pass through the specialized esophagus, while leucocytes become tethered and disabled there. Proteomics and transcriptomics have revealed, in addition to gut proteases, an amino acid transporter in gut tissue and other hydrolases, ion, and lipid transporters in the lumen, implicating the gut as the site for acquisition of essential lipids and inorganic ions. The surface is the principal entry route for glucose, whereas the gut dominates amino acid acquisition, especially in females. Heme, a potentially toxic hemoglobin degradation product, accumulates in the gut and, since schistosomes lack an anus, must be expelled by the poorly understood process of regurgitation. Here we place the new observations on the proteome of body surface and gut, and the entry of different nutrient classes into schistosomes, into the context of older studies on worm composition and metabolism. We suggest that the balance between surface and gut in nutrition is determined by the constraints of solute diffusion imposed by differences in male and female worm morphology. Our conclusions have major implications for worm survival under immunological or pharmacological pressure.


Asunto(s)
Interacciones Huésped-Parásitos/fisiología , Schistosoma/fisiología , Animales , Femenino , Humanos , Masculino , Esquistosomiasis/fisiopatología
15.
Expert Rev Proteomics ; 13(1): 19-33, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26558506

RESUMEN

Schistosomiasis is a neglected tropical disease of clinical significance that, despite years of research, still requires an effective vaccine and improved diagnostics for surveillance, control and potential elimination. Furthermore, the causes of host pathology during schistosomiasis are still not completely understood. The recent sequencing of the genomes of the three key schistosome species has enabled the discovery of many new possible vaccine and drug targets, as well as diagnostic biomarkers, using high-throughput and sensitive proteomics methods. This review focuses on the literature of the last 5 years that has reported on the use of proteomics to both better understand the biology of the schistosome parasites and the disease they cause in definitive mammalian hosts.


Asunto(s)
Proteínas del Helminto/metabolismo , Proteoma/metabolismo , Schistosoma/fisiología , Esquistosomiasis/parasitología , Animales , Proteínas del Helminto/inmunología , Proteínas del Helminto/aislamiento & purificación , Interacciones Huésped-Patógeno , Humanos , Proteoma/inmunología , Proteoma/aislamiento & purificación , Proteómica , Esquistosomiasis/diagnóstico , Esquistosomiasis/inmunología
16.
Cell Microbiol ; 17(6): 796-801, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25850569

RESUMEN

Schistosomiasis is a neglected tropical disease caused by infection with trematode parasites of the genus Schistosoma. Despite ongoing treatment programmes, the prevalence of schistosomiasis has failed to decline and the disease remains a cause of severe morbidity in millions of people. Understanding the biology of egg production by schistosomes is critical since eggs allow transmission of the infection, and when trapped in host tissues induce the immune responses that are responsible for the pathologic changes that underlie disease development. Unusually among trematodes, adult schistosomes exhibit sexual dimorphism and display a fascinating codependency in that the female is dependent on the male to grow and sexually mature. Thus, virgin females are developmentally stunted compared with females from mixed-sex infections and are unable to lay eggs. Moreover, fecund female schistosomes rapidly lose the ability to produce eggs when placed in tissue culture. Here we discuss the metabolic regulation of egg production in schistosomes, and in particular the critical role played by fatty acid oxidation in this process.


Asunto(s)
Schistosoma/fisiología , Cigoto/fisiología , Animales , Ácidos Grasos/metabolismo , Femenino , Fertilidad , Humanos , Masculino , Oxidación-Reducción
17.
Nat Rev Immunol ; 5(5): 420-6, 2005 05.
Artículo en Inglés | MEDLINE | ID: mdl-15864275

RESUMEN

Humans and the many parasites that we can host have co-evolved over millions of years. This has been compared to an arms race in which the immune armoury of the human has evolved to deal with potential pathogens and the pathogen has evolved strategies to evade, and in some cases use, the immune system of the human host. Recently, there have been marked changes in the exposure of individuals in the developed world to both microorganisms and metazoan parasites, so the immune stimuli such organisms provide no longer have a role in our lives. As we discuss here, this is a marked perturbation, and the absence of the associated immunomodulation might have led to the increased emergence of autoimmune diseases.


Asunto(s)
Enfermedades Autoinmunes/inmunología , Interacciones Huésped-Parásitos/inmunología , Schistosoma/inmunología , Esquistosomiasis/inmunología , Animales , Enfermedades Autoinmunes/genética , Autoinmunidad/inmunología , Interacciones Huésped-Parásitos/fisiología , Humanos , Schistosoma/fisiología , Linfocitos T Colaboradores-Inductores/inmunología
18.
PLoS Pathog ; 9(12): e1003781, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24385897

RESUMEN

Schistosomes, parasitic flatworms that cause the tropical disease schistosomiasis, are still a threat. They are responsible for 200 million infections worldwide and an estimated 280,000 deaths annually in sub-Saharan Africa alone. The adult parasites reside as pairs in the mesenteric or perivesicular veins of their human host, where they can survive for up to 30 years. The parasite is a potential activator of blood coagulation according to Virchow's triad, because it is expected to alter blood flow and endothelial function, leading to hypercoagulability. In contrast, hepatosplenic schistosomiasis patients are in a hypocoagulable and hyperfibrinolytic state, indicating that schistosomes interfere with the haemostatic system of their host. In this review, the interactions of schistosomes with primary haemostasis, secondary haemostasis, fibrinolysis, and the vascular tone will be discussed to provide insight into the reduction in coagulation observed in schistosomiasis patients. Interference with the haemostatic system by pathogens is a common mechanism and has been described for other parasitic worms, bacteria, and fungi as a mechanism to support survival and spread or enhance virulence. Insight into the mechanisms used by schistosomes to interfere with the haemostatic system will provide important insight into the maintenance of the parasitic life cycle within the host. This knowledge may reveal new potential anti-schistosome drug and vaccine targets. In addition, some of the survival mechanisms employed by schistosomes might be used by other pathogens, and therefore, these mechanisms that interfere with host haemostasis might be a broad target for drug development against blood-dwelling pathogens. Also, schistosome antithrombotic or thrombolytic molecules could form potential new drugs in the treatment of haemostatic disorders.


Asunto(s)
Hemostasis , Interacciones Huésped-Parásitos , Schistosoma/patogenicidad , Animales , Coagulación Sanguínea , Trastornos de la Coagulación Sanguínea/parasitología , Fibrinólisis , Humanos , Schistosoma/fisiología , Esquistosomiasis/complicaciones
19.
Clin Sci (Lond) ; 129(10): 875-83, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26201095

RESUMEN

Schistosomiasis is a major cause of portal hypertension worldwide. It associates with portal fibrosis that develops during chronic infection. The mechanisms by which the pathogen evokes these host responses remain unclear. We evaluated the hypothesis that schistosome eggs release factors that directly stimulate liver cells to produce osteopontin (OPN), a pro-fibrogenic protein that stimulates hepatic stellate cells to become myofibroblasts. We also investigated the utility of OPN as a biomarker of fibrosis and/or severity of portal hypertension. Cultured cholangiocytes, Kupffer cells and hepatic stellate cells were treated with soluble egg antigen (SEA); OPN production was quantified by quantitative reverse transcriptase polymerase chain reaction (qRTPCR) and ELISA; cell proliferation was assessed by BrdU (5-bromo-2'-deoxyuridine). Mice were infected with Schistosoma mansoni for 6 or 16 weeks to cause early or advanced fibrosis. Liver OPN was evaluated by qRTPCR and immunohistochemistry (IHC) and correlated with liver fibrosis and serum OPN. Livers from patients with schistosomiasis mansoni (early fibrosis n=15; advanced fibrosis n=72) or healthy adults (n=22) were immunostained for OPN and fibrosis markers. Results were correlated with plasma OPN levels and splenic vein pressures. SEA-induced cholangiocyte proliferation and OPN secretion (P<0.001 compared with controls). Cholangiocytes were OPN (+) in Schistosoma-infected mice and humans. Liver and serum OPN levels correlated with fibrosis stage (mice: r=0.861; human r=0.672, P=0.0001) and myofibroblast accumulation (mice: r=0.800; human: r=0.761, P=0.0001). Numbers of OPN (+) bile ductules strongly correlated with splenic vein pressure (r=0.778; P=0.001). S. mansoni egg antigens stimulate cholangiocyte proliferation and OPN secretion. OPN levels in liver and blood correlate with fibrosis stage and portal hypertension severity.


Asunto(s)
Proliferación Celular , Hipertensión Portal/metabolismo , Cirrosis Hepática/metabolismo , Osteopontina/metabolismo , Esquistosomiasis mansoni/metabolismo , Adolescente , Adulto , Animales , Antígenos Helmínticos/farmacología , Conductos Biliares/citología , Conductos Biliares/efectos de los fármacos , Conductos Biliares/metabolismo , Línea Celular , Células Cultivadas , Femenino , Células Estrelladas Hepáticas/efectos de los fármacos , Células Estrelladas Hepáticas/metabolismo , Interacciones Huésped-Parásitos , Humanos , Hipertensión Portal/genética , Hipertensión Portal/parasitología , Inmunohistoquímica , Macrófagos del Hígado/efectos de los fármacos , Macrófagos del Hígado/metabolismo , Cirrosis Hepática/genética , Cirrosis Hepática/parasitología , Masculino , Ratones , Persona de Mediana Edad , Osteopontina/sangre , Osteopontina/genética , Ratas , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Schistosoma/fisiología , Esquistosomiasis mansoni/genética , Esquistosomiasis mansoni/parasitología , Adulto Joven
20.
Parasitol Res ; 114(9): 3509-19, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26122990

RESUMEN

Schistosomiasis is the second widespread tropical disease that affects the health of over 240 million people of 78 countries. Questionnaires have been commonly used to diagnose schistosomiasis, while no meta-analysis of their efficacy had been reported previously. This meta-analysis was conducted to assess their diagnostic accuracy of schistosomiasis. Studies published prior to December 1, 2014, that had used questionnaires as a diagnostic tool were searched in PubMed, Medline, EMBASE, and China National Knowledge Infrastructure (CNKI) database. A total of 32 studies with 72,812 cases were identified for the meta-analysis. The best diagnostic odds ratio (DOR) was obtained from Schistosoma haematobium (67.68, 95 % confidence interval (CI) = 31.48 to 145.54), followed by Schistosoma japonicum (11.74, 95 % CI = 4.59 to 30.05) then Schistosoma mansoni (2.98, 95 % CI = 1.95 to 4.54). Pooled sensitivity and specificity were respectively 0.82, 0.88, and 0.46, and 0.59, 0.86, and 0.81 for S. japonicum, S. haematobium, and S. mansoni. The multivariable subgroup analyses showed that the questionnaires which had been pretested and standardized had better diagnostic performance. The result suggested that questionnaires can be used to diagnose schistosomiasis with moderate sensitivity and specificity and the questionnaires for diagnosing S. haematobium performed best.


Asunto(s)
Schistosoma/fisiología , Esquistosomiasis/diagnóstico , Animales , Humanos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Encuestas y Cuestionarios/normas
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