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Classification and characterization of Oncomelania hupensis circulating hemocytes. (A) Profile of circulating hemocyte populations in O. hupensis. Three major hemocyte subpopulations (R1 = small-FSLin between 160-360, R2 = medium-FSLin between 360-760 and R3 = large-FSLin > 760) can be identified by flow cytometric dot plot distributions based on their FSLin and SSLin parameters. (B) Scanning electron micrographs of the hemocytes isolated from O. hupensis snails. Three major cell subpopulations
Source publication
Schistosomiasis, caused by parasitic trematodes of the genus Schistosoma, remains a devastating public health problem, with over 200 million people infected and 779 million people at risk worldwide, especially in developing countries. The freshwater amphibious snail Oncomelania hupensis is the obligate intermediate host of Schistosoma japonicum. Th...
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... et al., 2009) allowed the separation of circulating hemocytes from small fragments. Flow cytometric analysis showed that circulating hemocytes from O. hupensis snails could be sepa- rated into three major cell subpopulations based mainly on size (forward scatter--FSLin) and granularity (side scatter--SSLin) dot plot distribution. As observed in Fig. 5A, the hemocyte subpopula- tions have been denominated small (R1--FSLin channels between 160-360), medium (R2--FSLin channels between 360-760) and large hemocytes (R3--FSLin channels >760). Furthermore, the SEM analysis also indicated that there were three different nucleus size hemocyte subpopulations (Fig. 5B, Ba-Bc). Each of the three ...
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... dot plot distribution. As observed in Fig. 5A, the hemocyte subpopula- tions have been denominated small (R1--FSLin channels between 160-360), medium (R2--FSLin channels between 360-760) and large hemocytes (R3--FSLin channels >760). Furthermore, the SEM analysis also indicated that there were three different nucleus size hemocyte subpopulations (Fig. 5B, Ba-Bc). Each of the three hemocyte subpopulations was further analysed based on internal complexity properties, referred as low (SSLin channels 180, 280, 380) and high granularity (SSLin channels !180, 280, 380) (Supple- mentary Fig. S1). Moreover, the TEM analysis (Fig. 5Ca-Cc) demon- strated that some hemocytes contained no granules ...
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... that there were three different nucleus size hemocyte subpopulations (Fig. 5B, Ba-Bc). Each of the three hemocyte subpopulations was further analysed based on internal complexity properties, referred as low (SSLin channels 180, 280, 380) and high granularity (SSLin channels !180, 280, 380) (Supple- mentary Fig. S1). Moreover, the TEM analysis (Fig. 5Ca-Cc) demon- strated that some hemocytes contained no granules (agranulocytes, AGs), which possessed elongated pseudopodia (Ep) and small vacuoles (Va) in the cytoplasm. The hemocytes con- taining some fewer and smaller conspicuous spherical granules were referred to as basophilic granulocytes (BGs), which generally had several prominent Ep ...
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... of O. hupen- sis hemocytes, and the results demonstrated that the circulating hemocytes in O. hupensis snails could be classified into three major cell subpopulations (small, medium and large) based predomi- nantly on cell size and each subpopulation can be separated into two subsets (low and high granularity) based mainly on granular- ity (Fig. 5). Additionally, we conducted OhMIF knockdown in vivo using the artificial feeding of dsRNA to study how OhMIF affects various types of hemocyte subpopulations and subsets. The results showed that the knockdown of OhMIF in snails significantly decreased the percentages of medium and large hemocyte subpop- ulations in the circulating ...
Citations
... Similar to B. glabrata, O. hupensis has two types of immune system: cellular and humoral [37]. Although research on the immune system of O. hupensis is relatively scarce, there has been a significant increase in recent years, and some research achievements have been made, which we will review later [37][38][39][40][41][42] (Fig. 2). ...
... To date, there is no consensus on the classification of haemocytes in O. hupensis as different studies propose different classification systems [37,39,65,66]. For instance, Xu et al. [65] classified the haemocytes in O. hupensis into granular round cells, agranular round cells, and spindle-shaped cells, while another research team categorized them into round cells with filopodia, acidophilic round cells without filopodia, alkaline round cells without filopodia, and spindle-shaped cells [67]. ...
... From the currently published articles, research on the factors and mechanisms involved in the immune interaction between O. hupensis and the S. japonicum is very limited. In recent years, some research progress has been made, and some immune factors and effector factors have been identified, including MIF [39,41], Toll-like receptor (TLR) [42], myeloid differentiation factor 88 (MyD88) [42,68], and thioredoxin (Trx) [40,69]. These immune and effector factors have been identified and functionally studied, involving stimulating cell proliferation, activating immune signaling pathways, regulating the release of toxic molecules, and increasing resistance to schistosome infection. ...
Schistosomiasis, the second largest parasitic disease in the world after malaria, poses a significant threat to human health and causes public health issues. The disease primarily affects populations in economically underdeveloped tropical regions, earning it the title of “neglected tropical disease”. Schistosomiasis is difficult to eradicate globally if medication alone is used. One of the essential elements of thorough schistosomiasis prevention and control is the management and disruption of the life cycle of intermediate host snails. The key approach to controlling the transmission of schistosomiasis is to control the intermediate hosts of the schistosome to disrupt its life cycle. We believe that approaching it from the perspective of the intermediate host’s immunity could be an environmentally friendly and potentially effective method. Currently, globally significant intermediate host snails for schistosomes include Oncomelania hupensis, Biomphalaria glabrata, and Bulinus truncatus. The immune interaction research between B. glabrata and Schistosoma mansoni has a history of several decades, and the complete genome sequencing of both B. glabrata and B. truncatus has been accomplished. We have summarized the immune-related factors and research progress primarily studied in B. glabrata and B. truncatus and compared them with several humoral immune factors that O. hupensis research focuses on: macrophage migration inhibitory factor (MIF), Toll-like receptors (TLRs), and thioredoxin (Trx). We believe that continued exploration of the immune interactions between O. hupensis and Schistosoma japonicum is valuable. This comparative analysis can provide some direction and clues for further in-depth research. Comparative immunological studies between them not only expand our understanding of the immune defense responses of snails that act as intermediaries for schistosomes but also facilitate the development of more comprehensive and integrated strategies for schistosomiasis prevention and control. Furthermore, it offers an excellent opportunity to study the immune system of gastropods and their co-evolution with pathogenic organisms.
Graphical Abstract
... In addition, the non-disruptive RNAi method was used in this study to introduce dsRNA into snails by feeding RNase III-deficient E. coli cells containing AOX-specific dsRNA, which may cause the unsteady RNAi knockdown efficiency but is optimal for the stress-related gene like AOX. This RNAi method was also proved to effectively silence the macrophage migration inhibitory factor gene in O. hupensis snails for four days [36]. ...
Background
Biomphalaria glabrata is one of the main intermediate hosts of Schistosoma mansoni, the most widespread species of Schistosoma. Our previous studies proved that alternative oxidase (AOX), the terminal oxidase in the mitochondrial respiratory chain, widely exists in several species of intermediate host snails of Schistosoma. Meanwhile, inhibition of AOX activity in Oncomelania hupensis snails could dramatically enhance the molluscicidal effect of niclosamide. As a hermaphroditic aquatic mollusc, the high fecundity and population density of B. glabrata increase the difficulty of snail control, which is one of the critical strategies for schistosomiasis elimination. The present study aimed to investigate the possible role of AOX in the development and fecundity of B. glabrata snail, which could be manipulated more manageable than other species of intermediate host snails of Schistosoma.
Methods
The dynamic expression of the AOX gene was investigated in different developmental stages and tissues of B. glabrata, with morphological change and oviposition behaviour observed from juvenile to adult snails. Furtherly, dsRNA-mediated knockdown of BgAOX mRNA and the AOX protein activity inhibiting was performed to investigate the effect of AOX on the development and oviposition of snails.
Results
The BgAOX gene expression profile is highly related to the development from late juveniles to adults, especially to the reproductive system of snails, with a positive correlation of 0.975 between egg production and BgAOX relative expression in ovotestis of snails. The inhibition of BgAOX at the transcriptional level and AOX activity could efficiently inhibit snail growth. However, the interference at the BgAOX protein activity level led to more severe tissue damage and more significant inhibition of oviposition than at the transcriptional level. This inhibition of growth and oviposition decreased gradually with the increase in the snail size.
Conclusions
The inhibition of AOX could efficiently disrupt the development and oviposition of B. glabrata snails, and the intervention targeting AOX at the juvenile stage is more effective for snails. This investigation explored the role of AOX in the growth and development of snails. It would benefit snail control in the future by providing a potential target while using molluscicides more efficiently.
Graphical abstract
... Available information about the mechanism involved in Oncomelania-Schistosoma interaction is presently limited. Recent investigations demonstrated that some immune-related genes such as MIF Huang et al., 2017), Toll-like receptor (TLR) , and myeloid differentiation factor 88 (MyD88) (Qian et al., 2017;Zhao et al., 2018), expressed significantly higher in haemocytes, and activated dramatically to defence against S. japonicum infection in specific signalling pathways. These implied the critical role of haemocytes in innate cellular defence responded to S. japonicum infection. ...
... Differently, macrophagelike and lymphocyte-like cells were defined as the two main categories of haemocytes by Pengsakul et al. (Pengsakul et al., 2013). With flow cytometry and electron microscope, haemocytes of O. hupensis were classified into three subpopulations (small, medium, and large) based on cell size, and each subpopulation can be separated into two subsets (low and high granularity) based on granularity (Huang et al., 2017). It is hard to get consistent classification for O. hupensis haemocytes and not a clear definition of different subsets with related functions. ...
... Based on the dye affinity, 41% basophilic granulocytes with blue staining colour and 59% eosinophilic granulocytes with pink (purple) staining colour were distinguished, and this difference was thought to correspond to lysosomal element during the maturation of young granulocytes containing basophilic granules to eosinophilic granulocytes in some bivalves including Ruditapes philippinarum (Cima et al., 2000). Huang et al. (2017) defined basophilic granulocytes in O. hupensis as those cells containing small and few granules and referred to eosinophilic granulocytes as those containing large and many electron-dense granules. Here, granulocytes of O. hupensis showed EDG, ELG, and DFG types of granules under TEM, appearing singly or in a cluster with different density in this study. ...
Oncomelania hupensis is the only obligatory intermediate host of Schistosoma japonicum, the pathogen of zoonosis schistosomiasis. Haemocytes play a critical role in the cellular immune defence of O. hupensis against S. japonicum challenge. Here, the morphology and classification of haemocytes of O. hupensis were investigated by Giemsa staining and light microscopy, combining with the scanning and transmission electron microscopy and flow cytometry. Granulocytes and hyalinocytes were confirmed as two main types of haemocytes, account for ∼10% and ∼90% of all haemocytes, with size varying in 4.3-10.9 μm and 0.4-30.8 μm, respectively. Subpopulations can be identified further by granule feature, shape, size, and surface and inner structure of cells. The heterogeneity in morphology implied varied developmental process and function of haemocyte subpopulations. After the S. japonicum challenge, haemocytes of O. hupensis respond to S. japonicum invasion immediately. The dynamic change of haemocyte subpopulations indicates that the small hyalinocyte could differentiate into a larger one or granulocyte after S. japonicum challenge, and the granulocytes and larger hyalinocytes play leading roles in early defence reaction, but in different ways. Phagocytosis and apoptosis of haemocytes in O. hupensis were proved to be related to immune defence against S. japonicum, with the combined effect of granulocytes and larger hyalinocytes. However, the main pathway of each subpopulation to take effect in different periods need further investigation.
... Huang et al. found that found that OhMIF displays significantly increased expression in snails following challenge with S. japonicum. Furthermore, Knockdown of OhMIF significantly reduced the percentage of phagocytic cell populations in circulating hemocytes [32]. Lately, Zhao et al. [33] identified 16 Toll-like receptors (TLRs) in O. hupensis. ...
Background:
The freshwater snail Oncomelania hupensis is the obligate intermediate host for Schistosoma japonicum in China. Transcriptomic examination of snail-schistosome interactions can provide valuable information of host response at physiological and immune levels.
Methods:
To investigate S. japonicum-induced changes in O. hupensis gene expression, we utilized high-throughput sequencing to identify transcripts that were differentially expressed between infected snails and their uninfected controls at two key time-point, Day 7 and Day 30 after challenge. Time-series transcriptomic profiles were analyzed using R package DESeq 2, followed by GO, KEGG and (weighted gene correlation network analysis) WGCNA analysis to elucidate and identify important molecular mechanism, and subsequently understand host-parasite relationship. The identified unigenes was verified by bioinformatics and real-time PCR. Possible adaptation molecular mechanisms of O. hupensis to S. japonicum challenge were proposed.
Results:
Transcriptomic analyses of O. hupensis by S. japonicum invasion yielded billion reads including 92,144 annotated transcripts. Over 5000 differentially expressed genes (DEGs) were identified by pairwise comparisons of infected libraries from two time points to uninfected libraries in O. hupensis. In total, 6032 gene ontology terms and 149 KEGG pathways were enriched. After the snails were infected with S. japonicum on Day 7 and Day 30, DEGs were shown to be involved in many key processes associated with biological regulation and innate immunity pathways. Gene expression patterns differed after exposure to S. japonicum. Using WGCNA, 16 modules were identified. Module-trait analysis identified that a module involved in RNA binding, ribosome, translation, mRNA processing, and structural constituent of ribosome were strongly associated with S. japonicum invasion. Many of the genes from enriched KEGG pathways were involved in lysosome, spliceosome and ribosome, indicating that S. japonicum invasion may activate the regulation of ribosomes and immune response to infection in O. hupensis.
Conclusions:
Our analysis provided a temporally dynamic gene expression pattern of O. hupensis by S. japonicum invasion. The identification of gene candidates serves as a foundation for future investigations of S. japonicum infection. Additionally, major DEGs expression patterns and putative key regulatory pathways would provide useful information to construct gene regulatory networks between host-parasite crosstalk.
... trematodes were isolated from the intestines of infected P. asotus. The Chinese mainland strain of S. japonicum was maintained by serial passage through O. hupensis snails and inbred Chinese Kun-ming mice (Tang et al., 2014;Huang et al., 2017). The mice were raised and housed at the Xiamen University Laboratory Animals Center (XMULAC) and the protocol was in strict accordance with good animal practice as defined by XMULAC. ...
... The O. hupensis snail bodies were isolated from their shells as described in previous studies (Huang et al., 2017;Peng and Zhou 2010). Snail tissue samples were homogenized in cold liquid nitrogen, resuspended with lysis buffer (8 M Urea, 2 M Thiourea, 65 mM DTT and Cocktail protease inhibitor) and broken by intermittent application of a FastPrep Ⓡ −24 homogenizer for a total of 1 min with intervals of 10 s. ...
... For example, in the gastropod snail, Biomphalaria glabrata, MIF contributes to the activation of immune responses, promotes immune cell proliferation, and inhibits p53-mediated apoptosis [12]. These functions seem to be general features of MIF in mollusks [13], but also occur in invertebrates such as crustaceans and echinoderms [14]. Even more intriguing were the findings that plants possess MIF genes (named MDL for MIF/DDT-like) [15], and that aphids secrete a MIF protein upon feeding to manipulate plant immunity [16]. ...
... Previous phylogenetic studies on MIF/D-DT (D-DT now also often referred to as MIF-2 [68]) in metazoans were either restricted to specific taxonomic groups such as insects [18], arthropods [69], or mollusks [70], or were focused on the relation between sequences from a single species and known sequences from vertebrates [14]. Several of these phylogenies supported a classification of MIF and D-DT variants from metazoans [13,71]. The present extended cross-kingdom analysis shows that MIF sequences from most metazoan phyla, such as nematodes, insects, or mollusks, do not form monophyletic groups. ...
Macrophage migration inhibitory factors (MIF) are multifunctional proteins regulating major processes in mammals, including activation of innate immune responses. MIF proteins also play a role in innate immunity of invertebrate organisms or serve as virulence factors in parasitic organisms, raising the question of their evolutionary history. We performed a broad survey of MIF presence or absence and evolutionary relationships across 803 species of plants, fungi, protists, and animals, and explored a potential relation with the taxonomic status, the ecology, and the lifestyle of individual species. We show that MIF evolutionary history in eukaryotes is complex, involving probable ancestral duplications, multiple gene losses and recent clade-specific re-duplications. Intriguingly, MIFs seem to be essential and highly conserved with many sites under purifying selection in some kingdoms (e.g., plants), while in other kingdoms they appear more dispensable (e.g., in fungi) or present in several diverged variants (e.g., insects, nematodes), suggesting potential neofunctionalizations within the protein superfamily.
... Recently, Tfh cells have emerged to play a beneficial role in mediating anti-parasitic immunity including the resistance to schistosome infections (12). For example, Chen et al. found that after S. japonicum infection, Tfh cells were recruited into the liver in large quantities to promote the formation of granuloma (13). ...
CD4⁺ T follicular helper (Tfh) cells, a new subset of immune cells, have been demonstrated to be involved in granulomatous responses to Schistosoma japonicum (S. japonicum) infection. However, the role and underlying mechanisms of Tfh cell aggregation in S. japonicum infection remain incompletely understood. In this study, we provide evidence that S. japonicum infection enhances the accumulation of Tfh cells in the spleen, lymph nodes, and peripheral blood of C57BL/6 mice. Infection-induced Tfh cells exhibited more potent effects directly on B cell responses than the control Tfh cells (P < 0.05). Furthermore, reduced apoptosis of Tfh cells was found both in S. japonicum infected mice and in soluble egg antigen (SEA) treated Tfh cells (P < 0.05). Mechanistic studies reveal that caspase-3 is the primary drivers of down-regulated apoptotic Tfh cell death in S. japonicum infection. In summary, this study demonstrates that Tfh cell accumulation might have an impact on the generation of immune responses in S. japonicum infection, and caspase-3 signaling mediated apoptosis down-regulation might responsible for the accumulation of Tfh cell in this course.
... RNAi-mediated knockdown confirmed immune function of B. glabrata MIF, yielding increased parasite burden following exposure to S. mansoni (Baeza-Garcia et al., 2010). Likewise, in Oncomelania hupensis a more distantly related prosobranch gastropod, expression of MIF increased after challenge with Schistosoma japonicum and its involvement in the activation, differentiation and recruitment of hemocytes was demonstrated: RNAi knockdown of MIF decreased the proportion of phagocytic circulating hemocytes and restrains the migration of blood cells from the host towards the site of infection (Huang et al., 2017). The abundance, in resistant snails, of transcripts related to pro-inflammatory signaling pathways (e.g. ...
The snail Pseudosuccinea columella is one of the main vectors of the medically-important trematode Fasciola
hepatica. In Cuba, the existence of natural P. columella populations that are either susceptible or resistant to F.
hepatica infection offers a unique snail-parasite for study of parasite-host compatibility and immune function in
gastropods. Here, we review all previous literature on this system and present new “omic” data that provide a
molecular baseline of both P. columella phenotypes from naïve snails. Comparison of whole snail transcriptomes
(RNAseq) and the proteomes of the albumen gland (2D-electrophoresis, MS) revealed that resistant and susceptible
strains differed mainly in an enrichment of particular biological processes/functions and a greater
abundance of proteins/transcripts associated with immune defense/stress response in resistant snails. These
results indicate a differential allocation of molecular resources to self-maintenance and survival in resistant P.
columella that may cause enhanced responsiveness to stressors (i.e. F. hepatica infection or tolerance to variations
in environmental pH/total water hardness), possibly as trade-off against reproduction and the ecological
cost of resistance previously suggested in resistant populations of P. columella.
... Ainsi, une première étude fonctionnelle a démontré que BgMIF1 du mollusque Biomphalaria glabrata présente certaines activités biologiques majeures du MIF humain, et participe à la réponse immunitaire après infection du mollusque par le parasite Schistosoma mansoni [16]. Différentes études ont ensuite identifié des MIFs chez d'autres invertébrés libres comme d'autres espèces de mollusques, des crustacés ou des échinodermes [17][18][19]. De façon inattendue, un travail de notre équipe a récemment montré que des parasites de plantes comme les pucerons du pois et du pêcher (Acyrthosiphon pisum et Myzus persicae) injectent également des MIFs dans leur plante hôte. Ces MIFs de pucerons modulent la réponse immunitaire de la plante et sont indispensables à l'établissement de l'infection [20]. ...
... Depuis, différentes études ont été réalisées sur d'autres espèces d'invertébrés comme des échinodermes (Patiria pectinifera [17] ), des arthropodes, des mollusques et des helminthes [11,18,19,35,36]. ...
Les cytokines MIFs (Macrophage Migration Inhibitory Factor) sont des protéines multifonctionnelles qui, chez les mammifères, interviennent dans plusieurs processus majeurs tels que le contrôle du cycle et de la mobilité cellulaire, l’activation de la réponse immunitaire et l’inhibition de l’apoptose. Des travaux récents montrent que les protéines MIFs peuvent également jouer un rôle majeur dans l’immunité des invertébrés, et être utilisées par des organismes parasites d’animaux ou de végétaux pour inhiber les défenses de leurs hôtes respectifs, ce qui soulève la question de leur diversité, de leur histoire évolutive et des potentielles différences fonctionnelles. L’objectif général de ce travail de thèse était d’explorer la diversité et l’histoire évolutive des protéines MIFs à une échelle trans-règne, puis de rechercher leurs éventuelles différences fonctionnelles, en se focalisant sur les systèmes plantes-pathogènes. Nous avons tout d’abord identifié les MIFs chez 803 espèces de plantes, champignons, protistes, et métazoaires, et analysé leur présence/absence et histoire évolutive en fonction des taxa, de l’écologie et du mode de vie (libre ou parasitaire) des espèces. Nous avons montré que l’histoire évolutive des MIFs, chez les eucaryotes, est complexe et implique des duplications ancestrales ainsi que des pertes multiples ou des re-duplications récentes. Les plantes (espèces libres autotrophes) et les parasites de plantes (autres que champignons) possèdent un nombre médian de trois MIFs, alors que les espèces hétérotrophes et les parasites d’animaux ont un nombre de MIF plus faible et/ou plus variable. De plus, les protéines MIFs semblent essentielles et fortement conservées, avec de nombreux résidus sous sélection purifiante, chez certains groupes comme les plantes, alors que dans d’autres groupes, elles semblent facultatives (e.g. champignons) ou présentes en plusieurs copies divergentes (e.g. nématodes, insectes), ce qui suggère de potentielles néofonctionalisations. Nous avons ensuite analysé l’effet des protéines MIFs de plusieurs espèces sur la mort cellulaire en système végétal. Tous les organismes testés (plantes oomycètes, protozoaires, insectes et nématodes), y compris ceux n’ayant pas d’interaction avec les plantes, possèdent au moins une protéine MIF capable d’inhiber cette mort cellulaire. Cela suggère que l’inhibition de la mort cellulaire en plante ne correspond pas à une néofonctionalisation des MIFs de parasites de plantes, mais serait liée à des propriétés structurales et conservées des MIFs. Toutefois, aucun des paramètres étudiés (localisation subcellulaire) ou prédits in silico (présence de motifs, structures 3D, oligomérisation, modifications post-traductionnelles) ne semble lié à cette activité d’inhibition de la mort cellulaire. De futures études fonctionnelles poussées sont nécessaires à l’élucidation des relations structure/fonction de ces protéines complexes.
... Furthermore, schistosome proteases and snail protease inhibitors may become engaged in an enzymatic battle for compatibility via adhesion of protease inhibitors at the parasite surface to counteract against parasitic proteases [78]. Snail effectorsheat shock protein 70 (Hsp70), ferritin, granulin, a guadeloupe resistance complex protein (Grctm6), and migration inhibitory factor (MIF)induce the proliferation of snail hemocytes in response to tissue damage or cercaria development to regulate the compatibility/incompatibility of snails/schistosomes [84][85][86][87][88][89][90][91]. ...
This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal)
This article has been retracted at the request of the authors: Benjamin Sanogo, Dongjuan Yuan, Xin Zeng, Yanhua Zhang, and Zhongdao Wu.
Our article reviews the evolution, geography, diversity, genetics and host-compatibility of human schistosomes and their hosts. It has come to our attention that readers have found some of the content in the article to be confusing or misleading. As authors, we have tried our best to share our scientific discovery and understanding faithfully, but we also agree that scientific reports should stand up to doubt and discussion. After serious consideration, to avoid confusion in the Schistosoma research community, we are retracting the Review. We apologize to the community for any inconvenience we have caused.
