Pub Date : 2024-09-01DOI: 10.1016/j.ijpara.2024.05.001
Chagas disease affects millions of people in Colombia and worldwide, with its transmission influenced by ecological, environmental, and anthropogenic factors. There is a notable correlation between vector transmission cycles and the habitats of insect vectors of the parasite. However, the scale at which these cycles operate remains uncertain. While individual triatomine ecotopes such as palms provide conditions for isolated transmission cycles, recent studies examining triatomine blood sources in various habitats suggest a more intricate network of transmission cycles, linking wild ecotopes with human dwellings. This study aims to provide further evidence on the complexity of the scale of Trypanosoma cruzi transmission cycles, by exploring the different blood sources among developmental stages of infected triatomines in different habitats. We evaluated infection rates, parasite loads, feeding sources, and the distribution of Rhodnius prolixus insects in Attalea butyracea palms across three distinct habitats in Casanare, Colombia: peridomestics, pastures, and woodlands. Our results show that there is no clear independence in transmission cycles in each environment. Analyses of feeding sources suggest the movement of insects and mammals (primarily bats and didelphids) among habitats. A significant association was found between habitat and instar stages in collected R. prolixus. The N1 stage was correlated with pasture and woodland, while the N4 stage was related to pasture. Additionally, adult insects exhibited higher T. cruzi loads than N1, N2, and N3. We observed higher T. cruzi loads in insects captured in dwelling and pasture habitats, compared with those captured in woodland areas. Effective Chagas disease control strategies must consider the complexity of transmission cycles and the interplay between domestic and sylvatic populations of mammals and vectors.
南美锥虫病影响着哥伦比亚和全世界数百万人,其传播受生态、环境和人为因素的影响。病媒传播周期与寄生虫昆虫病媒的栖息地之间存在明显的相关性。然而,这些周期的运作规模仍不确定。虽然棕榈树等个别三蠹生态群落为孤立的传播周期提供了条件,但最近对不同栖息地的三蠹血源进行的研究表明,传播周期网络更加错综复杂,将野生生态群落与人类居住地联系在一起。本研究旨在通过探究不同栖息地中受感染三蠹发育阶段的不同血液来源,进一步证明克氏锥虫传播周期规模的复杂性。我们评估了哥伦比亚卡萨纳雷三种不同栖息地(围牧场、牧场和林地)的感染率、寄生虫量、食源以及Attalea butyracea棕榈中Rhodnius prolixus昆虫的分布情况。我们的研究结果表明,每种环境中的传播周期都没有明显的独立性。对食物来源的分析表明,昆虫和哺乳动物(主要是蝙蝠和蚜虫)在不同的栖息地之间流动。在采集到的 R. prolixus 中,栖息地与分化阶段之间存在明显的关联。N1 阶段与牧场和林地相关,而 N4 阶段与牧场相关。此外,与 N1、N2 和 N3 相比,成虫表现出更高的 T. cruzi 负荷。我们观察到,与在林地捕获的昆虫相比,在住所和牧场捕获的昆虫体内有更高的南美锥虫病病毒载量。有效的南美锥虫病控制策略必须考虑到传播周期的复杂性,以及哺乳动物和病媒在家养种群和草原种群之间的相互作用。
{"title":"Exploring dietary differences among developmental stages of triatomines infected with Trypanosoma cruzi in different habitats","authors":"","doi":"10.1016/j.ijpara.2024.05.001","DOIUrl":"10.1016/j.ijpara.2024.05.001","url":null,"abstract":"<div><p>Chagas disease affects millions of people in Colombia and worldwide, with its transmission influenced by ecological, environmental, and anthropogenic factors. There is a notable correlation between vector transmission cycles and the habitats of insect vectors of the parasite. However, the scale at which these cycles operate remains uncertain. While individual triatomine ecotopes such as palms provide conditions for isolated transmission cycles, recent studies examining triatomine blood sources in various habitats suggest a more intricate network of transmission cycles, linking wild ecotopes with human dwellings. This study aims to provide further evidence on the complexity of the scale of <em>Trypanosoma cruzi</em> transmission cycles, by exploring the different blood sources among developmental stages of infected triatomines in different habitats. We evaluated infection rates, parasite loads, feeding sources, and the distribution of <em>Rhodnius prolixus</em> insects in <em>Attalea butyracea</em> palms across three distinct habitats in Casanare, Colombia: peridomestics, pastures, and woodlands. Our results show that there is no clear independence in transmission cycles in each environment. Analyses of feeding sources suggest the movement of insects and mammals (primarily bats and didelphids) among habitats. A significant association was found between habitat and instar stages in collected <em>R. prolixus</em>. The N1 stage was correlated with pasture and woodland, while the N4 stage was related to pasture. Additionally, adult insects exhibited higher <em>T. cruzi</em> loads than N1, N2, and N3. We observed higher <em>T. cruzi</em> loads in insects captured in dwelling and pasture habitats, compared with those captured in woodland areas. Effective Chagas disease control strategies must consider the complexity of transmission cycles and the interplay between domestic and sylvatic populations of mammals and vectors.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0020751924001073/pdfft?md5=96a3bbd4f11f3639150ed3d465355083&pid=1-s2.0-S0020751924001073-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140957274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.ijpara.2024.04.008
Parasites can indirectly impact hosts through non-consumptive effects (NCEs) via changes in behaviour, morphology, and/or physiology. These responses can be understood in terms of the ecology of fear (ectoparasites) or the ecology of disgust (endoparasites) framework. We tested the hypothesis that NCEs of parasite exposure (e.g., parasite avoidance and defense) trade off with other important behaviours such as feeding and resting. We predicted that when exposed to parasites (without infection), hosts will increase their defensive behaviors at the expense of feeding. We also posited that history of exposure (without infection), or previous infection would impact the expression of these NCEs. The study system involves a cactophilic fruit fly (Drosophila nigrospiracula) and a naturally occurring parasitic mite (Macrocheles subbadius). First, we assessed how prior mite exposure affected fly behaviour in response to current parasite exposure. Mite presence resulted in increased grooming and movement, but exposure history did not affect these behaviours. However, the interaction between previous and current exposure influenced host feeding and resting behaviours. We found that previously exposed flies increased feeding and decreased resting upon a secondary mite exposure. In a second experiment, we tested the role of infection history on current parasite exposure. Compared with naïve flies, previously infected flies were expected to increase defensive behaviours upon secondary exposure. Flies increased defensive and ambulatory behaviour in the presence of mites, and consequently less time was spent resting but feeding was unaffected. None of the behaviours measured were affected by previous infection status. In general, current parasite exposure resulted in NCEs. Moreover, our results showed that previous exposure (without infection) to parasites may have an even stronger effect upon secondary exposure than infection history. Our study highlights the importance of the ecology of fear and the role that exposure and infection history plays in generating NCEs of parasitism.
{"title":"Ghosts of parasites past influence current non-consumptive effects in Drosophila nigrospiracula","authors":"","doi":"10.1016/j.ijpara.2024.04.008","DOIUrl":"10.1016/j.ijpara.2024.04.008","url":null,"abstract":"<div><p>Parasites can indirectly impact hosts through non-consumptive effects (NCEs) via changes in behaviour, morphology, and/or physiology. These responses can be understood in terms of the ecology of fear (ectoparasites) or the ecology of disgust (endoparasites) framework. We tested the hypothesis that NCEs of parasite exposure (e.g., parasite avoidance and defense) trade off with other important behaviours such as feeding and resting. We predicted that when exposed to parasites (without infection), hosts will increase their defensive behaviors at the expense of feeding. We also posited that history of exposure (without infection), or previous infection would impact the expression of these NCEs. The study system involves a cactophilic fruit fly (<em>Drosophila nigrospiracula</em>) and a naturally occurring parasitic mite (<em>Macrocheles subbadius</em>). First, we assessed how prior mite exposure affected fly behaviour in response to current parasite exposure. Mite presence resulted in increased grooming and movement, but exposure history did not affect these behaviours. However, the interaction between previous and current exposure influenced host feeding and resting behaviours. We found that previously exposed flies increased feeding and decreased resting upon a secondary mite exposure. In a second experiment, we tested the role of infection history on current parasite exposure. Compared with naïve flies, previously infected flies were expected to increase defensive behaviours upon secondary exposure. Flies increased defensive and ambulatory behaviour in the presence of mites, and consequently less time was spent resting but feeding was unaffected. None of the behaviours measured were affected by previous infection status. In general, current parasite exposure resulted in NCEs. Moreover, our results showed that previous exposure (without infection) to parasites may have an even stronger effect upon secondary exposure than infection history. Our study highlights the importance of the ecology of fear and the role that exposure and infection history plays in generating NCEs of parasitism.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S002075192400078X/pdfft?md5=071607e5ac2bf5976c8f7eeb0ce9c541&pid=1-s2.0-S002075192400078X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140793131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.ijpara.2024.05.003
Xenobiotic biotransformation is an important modulator of anthelmintic drug potency and a potential mechanism of anthelmintic resistance. Both the free-living nematode Caenorhabditis elegans and the ruminant parasite Haemonchus contortus biotransform benzimidazole drugs by glucose conjugation, likely catalysed by UDP-glycosyltransferase (UGT) enzymes. To identify C. elegans genes involved in benzimidazole drug detoxification, we first used a comparative phylogenetic analysis of UGTs from humans, C. elegans and H. contortus, combined with available RNAseq datasets to identify which of the 63 C. elegans ugt genes are most likely to be involved in benzimidazole drug biotransformation. RNA interference knockdown of 15 prioritized C. elegans genes identified those that sensitized animals to the benzimidazole derivative albendazole (ABZ). Genetic mutations subsequently revealed that loss of ugt-9 and ugt-11 had the strongest effects. The “ugt-9 cluster” includes these genes, together with six other closely related ugts. A CRISPR-Cas-9 deletion that removed seven of the eight ugt-9 cluster genes had greater ABZ sensitivity than the single largest-effect mutation. Furthermore, a double mutant of ugt-22 (which is not a member of the ugt-9 cluster) with the ugt-9 cluster deletion further increased ABZ sensitivity. This additivity of mutant phenotypes suggest that ugt genes act in parallel, which could have several, not mutually exclusive, explanations. ugt mutations have different effects with different benzimidazole derivatives, suggesting that enzymes with different specificities could together more efficiently detoxify drugs. Expression patterns of ugt-9, ugt-11 and ugt-22 gfp reporters differ and so likely act in different tissues which may, at least in part, explain their additive effects on drug potency. Overexpression of ugt-9 alone was sufficient to confer partial ABZ resistance, indicating increasing total UGT activity protects animals. In summary, our results suggest that the multiple UGT enzymes have overlapping but not completely redundant functions in benzimidazole drug detoxification and may represent “druggable” targets to improve benzimidazole drug potency.
{"title":"Multiple UDP glycosyltransferases modulate benzimidazole drug sensitivity in the nematode Caenorhabditis elegans in an additive manner","authors":"","doi":"10.1016/j.ijpara.2024.05.003","DOIUrl":"10.1016/j.ijpara.2024.05.003","url":null,"abstract":"<div><p>Xenobiotic biotransformation is an important modulator of anthelmintic drug potency and a potential mechanism of anthelmintic resistance. Both the free-living nematode <em>Caenorhabditis elegans</em> and the ruminant parasite <em>Haemonchus contortus</em> biotransform benzimidazole drugs by glucose conjugation, likely catalysed by UDP-glycosyltransferase (UGT) enzymes. To identify <em>C. elegans</em> genes involved in benzimidazole drug detoxification, we first used a comparative phylogenetic analysis of UGTs from humans<em>, C. elegans</em> and <em>H. contortus,</em> combined with available RNAseq datasets to identify which of the 63 <em>C. elegans ugt</em> genes are most likely to be involved in benzimidazole drug biotransformation<em>.</em> RNA interference knockdown of 15 prioritized <em>C. elegans</em> genes identified those that sensitized animals to the benzimidazole derivative albendazole (ABZ). Genetic mutations subsequently revealed that loss of <em>ugt-9</em> and <em>ugt-11</em> had the strongest effects. The “<em>ugt-9 cluster</em>” includes these genes, together with six other closely related <em>ugt</em>s. A CRISPR-Cas-9 deletion that removed seven of the eight <em>ugt-9 cluster</em> genes had greater ABZ sensitivity than the single largest-effect mutation. Furthermore, a double mutant of <em>ugt-22</em> (which is not a member of the <em>ugt-9 cluster)</em> with the <em>ugt-9 cluster</em> deletion further increased ABZ sensitivity. This additivity of mutant phenotypes suggest that <em>ugt</em> genes act in parallel, which could have several, not mutually exclusive, explanations. <em>ugt</em> mutations have different effects with different benzimidazole derivatives, suggesting that enzymes with different specificities could together more efficiently detoxify drugs. Expression patterns of <em>ugt-9, ugt-11</em> and <em>ugt-22 gfp</em> reporters differ and so likely act in different tissues which may, at least in part, explain their additive effects on drug potency. Overexpression of <em>ugt-9</em> alone was sufficient to confer partial ABZ resistance, indicating increasing total UGT activity protects animals. In summary, our results suggest that the multiple UGT enzymes have overlapping but not completely redundant functions in benzimidazole drug detoxification and may represent “druggable” targets to improve benzimidazole drug potency.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0020751924001097/pdfft?md5=1b485fbd725694b19b4f5bc56ae0cd6f&pid=1-s2.0-S0020751924001097-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141161331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.ijpara.2024.06.003
Establishing an intact intracellular parasitophorous vacuole (PV) that enables efficient nutrient uptake and protein trafficking is essential for the survival and proliferation of Toxoplasma gondii. Although the PV membrane (PVM)-localized dense granule protein 17 (GRA17) and GRA23 mediate the permeability of the PVM to small molecules, including nutrient uptake and excretion of metabolic by-products, the molecular mechanism by which T. gondii acquires nutrients remains unclear. In this study, we showed that the secreted protein GRA47 contributed to normal PV morphology, PVM permeability to small molecules, growth, and virulence in T. gondii. Co-immunoprecipitation analysis demonstrated potential interaction of GRA47 with GRA72, and the loss of GRA72 affected PV morphology, parasite growth and infectivity. To investigate the biological relationship among GRA47, GRA72, GRA17 and GRA23, attempts were made to construct strains with double gene deletion and overexpressing strains. Only Δgra23Δgra72 was successfully constructed. This strain exhibited a significant increase in the proportion of aberrant PVs compared with the Δgra23 strain. Overexpressing one of the three related GRAs partially rescued PVs with aberrant morphology in Δgra47, Δgra72 and Δgra17, while the expression of the Plasmodium falciparum PVM protein PfExp2, an ortholog of GRA17 and GRA23, fully rescued the PV morphological defect in all three Δgra strains. These results suggest that these GRA proteins may not be functionally redundant but rather work in different ways to regulate nutrient acquisition. These findings highlight the versatility of the nutrient uptake mechanisms in T. gondii, which may contribute to the parasite’s remarkable ability to grow in different cellular niches in a very broad range of hosts.
{"title":"GRA47 is important for the morphology and permeability of the parasitophorous vacuole in Toxoplasma gondii","authors":"","doi":"10.1016/j.ijpara.2024.06.003","DOIUrl":"10.1016/j.ijpara.2024.06.003","url":null,"abstract":"<div><p>Establishing an intact intracellular parasitophorous vacuole (PV) that enables efficient nutrient uptake and protein trafficking is essential for the survival and proliferation of <span><em>Toxoplasma gondii</em></span><span>. Although the PV membrane (PVM)-localized dense granule protein 17 (GRA17) and GRA23 mediate the permeability of the PVM to small molecules, including nutrient uptake and excretion of metabolic by-products, the molecular mechanism by which </span><em>T. gondii</em> acquires nutrients remains unclear. In this study, we showed that the secreted protein GRA47 contributed to normal PV morphology, PVM permeability to small molecules, growth, and virulence in <em>T. gondii</em>. Co-immunoprecipitation analysis demonstrated potential interaction of GRA47 with GRA72, and the loss of GRA72 affected PV morphology, parasite growth and infectivity. To investigate the biological relationship among GRA47, GRA72, GRA17 and GRA23, attempts were made to construct strains with double gene deletion and overexpressing strains. Only Δ<em>gra</em>23Δ<em>gra72</em> was successfully constructed. This strain exhibited a significant increase in the proportion of aberrant PVs compared with the Δ<em>gra23</em> strain. Overexpressing one of the three related GRAs partially rescued PVs with aberrant morphology in Δ<em>gra47</em>, Δ<em>gra72</em> and Δ<em>gra17</em>, while the expression of the <em>Plasmodium falciparum</em> PVM protein <em>Pf</em>Exp2, an ortholog of GRA17 and GRA23, fully rescued the PV morphological defect in all three Δ<em>gra</em> strains. These results suggest that these GRA proteins may not be functionally redundant but rather work in different ways to regulate nutrient acquisition. These findings highlight the versatility of the nutrient uptake mechanisms in <em>T. gondii</em>, which may contribute to the parasite’s remarkable ability to grow in different cellular niches in a very broad range of hosts.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141467798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-30DOI: 10.1016/j.ijpara.2024.08.005
Célia Koellsch, Robert Poulin, Priscila M Salloum
The fast technological advances of molecular tools have enabled us to uncover a new dimension hidden within parasites and their hosts: their microbiomes. Increasingly, parasitologists characterise host microbiome changes in the face of parasitic infections, revealing the potential of these microscopic fast-evolving entities to influence host-parasite interactions. However, most of the changes in host microbiomes seem to depend on the host and parasite species in question. Furthermore, we should understand the relative role of parasitic infections as microbiome modulators when compared with other microbiome-impacting factors (e.g., host size, age, sex). Here, we characterised the microbiome of a single intermediate host species infected by two parasites belonging to different phyla: the acanthocephalan Plagiorhynchus allisonae and a dilepidid cestode, both infecting Transorchestia serrulata amphipods collected simultaneously from the same locality. We used the v4 hypervariable region of the 16S rRNA prokaryotic gene to identify the hemolymph bacterial community of uninfected, acanthocephalan-infected, and cestode-infected amphipods, as well as the bacteria in the amphipods' immediate environment and in the parasites infecting them. Our results show that parasitic infections were more strongly associated with differences in host bacterial community richness than amphipod size, presence of amphipod eggs in female amphipods, and even parasite load. Amphipods infected by acanthocephalans had the most divergent bacterial community, with a marked decrease in alpha diversity compared with cestode-infected and uninfected hosts. In accordance with the species-specific nature of microbiome changes in parasitic infections, we found unique microbial taxa associating with hosts infected by each parasite species, as well as taxa only shared between a parasite species and their infected hosts. However, there were some bacterial taxa detected in all parasitised amphipods (regardless of the parasite species), but not in uninfected amphipods or the environment. We propose that shared bacteria associated with all hosts parasitised by distantly related helminths may be important either in helping host defences or parasites' success, and could thus interact with host-parasite evolution.
{"title":"What shapes a microbiome? Differences in bacterial communities associated with helminth-amphipod interactions.","authors":"Célia Koellsch, Robert Poulin, Priscila M Salloum","doi":"10.1016/j.ijpara.2024.08.005","DOIUrl":"10.1016/j.ijpara.2024.08.005","url":null,"abstract":"<p><p>The fast technological advances of molecular tools have enabled us to uncover a new dimension hidden within parasites and their hosts: their microbiomes. Increasingly, parasitologists characterise host microbiome changes in the face of parasitic infections, revealing the potential of these microscopic fast-evolving entities to influence host-parasite interactions. However, most of the changes in host microbiomes seem to depend on the host and parasite species in question. Furthermore, we should understand the relative role of parasitic infections as microbiome modulators when compared with other microbiome-impacting factors (e.g., host size, age, sex). Here, we characterised the microbiome of a single intermediate host species infected by two parasites belonging to different phyla: the acanthocephalan Plagiorhynchus allisonae and a dilepidid cestode, both infecting Transorchestia serrulata amphipods collected simultaneously from the same locality. We used the v4 hypervariable region of the 16S rRNA prokaryotic gene to identify the hemolymph bacterial community of uninfected, acanthocephalan-infected, and cestode-infected amphipods, as well as the bacteria in the amphipods' immediate environment and in the parasites infecting them. Our results show that parasitic infections were more strongly associated with differences in host bacterial community richness than amphipod size, presence of amphipod eggs in female amphipods, and even parasite load. Amphipods infected by acanthocephalans had the most divergent bacterial community, with a marked decrease in alpha diversity compared with cestode-infected and uninfected hosts. In accordance with the species-specific nature of microbiome changes in parasitic infections, we found unique microbial taxa associating with hosts infected by each parasite species, as well as taxa only shared between a parasite species and their infected hosts. However, there were some bacterial taxa detected in all parasitised amphipods (regardless of the parasite species), but not in uninfected amphipods or the environment. We propose that shared bacteria associated with all hosts parasitised by distantly related helminths may be important either in helping host defences or parasites' success, and could thus interact with host-parasite evolution.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142107086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.1016/j.ijpara.2024.04.010
Coprological and serological diagnostic tests were compared to define the status of a pig farm with regard to Ascaris suum. On each of the 100 farms in France visited for the study, 10 blood samples were taken from pigs at the end of fattening (at least 22 weeks old) and 20 to 30 faecal samples were taken, depending on the category of animals present on the farm (10 sows, 10 piglets aged 10 to 12 weeks and 10 pigs at the end of fattening, aged at least 22 weeks). A SERASCA® ELISA test (Laboratory of Parasitology, Ghent University) was performed on each blood sample (cut-off 0.5) and a coprological analysis on each faecal sample. A Bayesian approach was used to estimate the sensitivity and specificity of the coprological and serological tests. A farm was considered positive if at least one A. suum egg was observed in the faecal samples. With regard to the serological test, various hypotheses were tested in order to define the number of seropositive animals required to consider a farm positive for A. suum. The coprological test has very good specificity in the search for A. suum, whether 20 or 30 samples are taken per farm. However, even with an increase in the number of samples, the sensitivity of this diagnostic approach is very low (less than 30%). On the other hand, the serological diagnostic method, which consists of taking blood samples from 10 animals at the end of fattening, has good sensitivity and seems better suited to defining the status of a farm with regard to A. suum, provided that a farm is considered seropositive only if two out of 10 samples are positive.
{"title":"Bayesian estimation of the sensitivity and specificity of coprological and serological diagnostic tests for the detection of Ascaris suum infection on pig farms","authors":"","doi":"10.1016/j.ijpara.2024.04.010","DOIUrl":"10.1016/j.ijpara.2024.04.010","url":null,"abstract":"<div><p>Coprological and serological diagnostic tests were compared to define the status of a pig farm with regard to <em>Ascaris suum</em>. On each of the 100 farms in France visited for the study, 10 blood samples were taken from pigs at the end of fattening (at least 22 weeks old) and 20 to 30 faecal samples were taken, depending on the category of animals present on the farm (10 sows, 10 piglets aged 10 to 12 weeks and 10 pigs at the end of fattening, aged at least 22 weeks). A SERASCA® ELISA test (Laboratory of Parasitology, Ghent University) was performed on each blood sample (cut-off 0.5) and a coprological analysis on each faecal sample. A Bayesian approach was used to estimate the sensitivity and specificity of the coprological and serological tests. A farm was considered positive if at least one <em>A. suum</em> egg was observed in the faecal samples. With regard to the serological test, various hypotheses were tested in order to define the number of seropositive animals required to consider a farm positive for <em>A. suum</em>. The coprological test has very good specificity in the search for <em>A. suum</em>, whether 20 or 30 samples are taken per farm. However, even with an increase in the number of samples, the sensitivity of this diagnostic approach is very low (less than 30%). On the other hand, the serological diagnostic method, which consists of taking blood samples from 10 animals at the end of fattening, has good sensitivity and seems better suited to defining the status of a farm with regard to <em>A. suum</em>, provided that a farm is considered seropositive only if two out of 10 samples are positive.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0020751924000808/pdfft?md5=a406f431556c5d7ac96323016073abfe&pid=1-s2.0-S0020751924000808-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140766302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.1016/j.ijpara.2024.04.006
Infection by the zoonotic fish-borne trematode, Opisthorchis viverrini, remains a crucial health issue in Thailand and neighboring countries. Recently, molecular analysis revealed two populations of putative O. viverrini: one found primarily in human hosts (“human-specific” population) and the other primarily in cats (“cat-specific” population). It is unclear how the infective stages (metacercariae) of these different populations circulate among definitive and reservoir hosts in nature. To gain an insight into this, mitochondrial cox1 and nad1 gene sequences of metacercariae from fish intermediate hosts were examined. None of 192 metacercariae from cyprinid fish in Lao PDR and Thailand had sequences typical of “cat-specific” O. viverrini, suggesting that cyprinid fish are not the main second intermediate hosts of this population. Interestingly, all 20 O. viverrini-like metacercariae from snakehead fish (Channa striata) shared 99.51–100% sequence identity with eggs from cats naturally infected in a previous study. Hence, we propose a modification of the known transmission dynamics of O. viverrini: consumption of metacercariae within snakehead fish provides another pathway for cats and (occasionally) humans to acquire infection. We also performed morphological comparisons of eggs, metacercariae, and adult flukes (raised in hamsters) of both Opisthorchis populations. The “cat-specific” population has eggs that are narrower and adults that are shorter and wider than in the human-specific population. The metacercaria of the “cat-specific” population is elliptical, while that of the “human-specific” population is oval, occasionally rounded. Our results confirmed that O. viverrini-like metacercariae from snakehead fish are the infective stages of the “cat-specific” fluke. This provides a new insight into the dissemination and transmission of each population in the second intermediate host. The identity of the cat-specific population is discussed.
{"title":"Exploring the second intermediate hosts and morphology of human- and cat-specific Opisthorchis viverrini-like populations","authors":"","doi":"10.1016/j.ijpara.2024.04.006","DOIUrl":"10.1016/j.ijpara.2024.04.006","url":null,"abstract":"<div><p>Infection by the zoonotic fish-borne trematode, <em>Opisthorchis viverrini,</em> remains a crucial health issue in Thailand and neighboring countries. Recently, molecular analysis revealed two populations of putative <em>O. viverrini</em>: one found primarily in human hosts (“human-specific” population) and the other primarily in cats (“cat-specific” population). It is unclear how the infective stages (metacercariae) of these different populations circulate among definitive and reservoir hosts in nature. To gain an insight into this, mitochondrial <em>cox</em>1 and <em>nad</em>1 gene sequences of metacercariae from fish intermediate hosts were examined. None of 192 metacercariae from cyprinid fish in Lao PDR and Thailand had sequences typical of “cat-specific” <em>O. viverrini</em>, suggesting that cyprinid fish are not the main second intermediate hosts of this population. Interestingly, all 20 <em>O. viverrini</em>-like metacercariae from snakehead fish (<em>Channa striata</em>) shared 99.51–100% sequence identity with eggs from cats naturally infected in a previous study. Hence, we propose a modification of the known transmission dynamics of <em>O. viverrini</em>: consumption of metacercariae within snakehead fish provides another pathway for cats and (occasionally) humans to acquire infection. We also performed morphological comparisons of eggs, metacercariae, and adult flukes (raised in hamsters) of both <em>Opisthorchis</em> populations. The “cat-specific” population has eggs that are narrower and adults that are shorter and wider than in the human-specific population. The metacercaria of the “cat-specific” population is elliptical, while that of the “human-specific” population is oval, occasionally rounded. Our results confirmed that <em>O. viverrini</em>-like metacercariae from snakehead fish are the infective stages of the “cat-specific” fluke. This provides a new insight into the dissemination and transmission of each population in the second intermediate host. The identity of the cat-specific population is discussed.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140762471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.1016/j.ijpara.2024.04.009
Theileria parva causes East Coast fever (ECF), one of the most important and lethal tick-borne diseases of cattle in sub-Saharan Africa. ECF is a considerable burden to the livestock industry, causing annual losses exceeding US $300 million. Currently, diagnosis of T. parva infections relies mainly on clinical signs, serology, and microscopic identification of parasites in either blood or lymph fluid samples. However, some of these tests might not indicate ongoing infection and they all lack the sensitivity to detect low-level infections. Molecular tests such as nested and quantitative PCR assays offer high sensitivity for detection of T. parva. However, these tests remain highly complex technologies that are impractical to use in resource-limited settings where economic losses due to the disease have the most significant impact. A field-deployable, point-of-care test will be of significant value in the treatment and control of ECF in endemic areas. For this purpose, we have developed a CRISPR-Cas12a-based pen-side tool that can sensitively and specifically detect T. parva based on the p104 gene. We describe a streamlined, field-applicable diagnostic tool comprising a 20 min recombinase polymerase amplification (RPA) reaction followed by a 60 min CRISPR-Cas12a reaction using a FAM/Biotin lateral flow strip readout. We tested two different RPA primer pairs and four different CRISPR-RNAs (crRNAs). The p104-based assay displayed high sensitivity, detecting as low as one infected lymphocyte per three microliters of blood and universally detecting eight different T. parva strains without detecting DNA from other Theileria spp. such as Theileria mutans and Theileria lestoquardi. This work opens the way for a field-applicable diagnostic tool for the sensitive point-of-care early diagnosis of T. parva infections in cattle.
{"title":"Novel CRISPR-Cas-powered pen-side test for East Coast fever","authors":"","doi":"10.1016/j.ijpara.2024.04.009","DOIUrl":"10.1016/j.ijpara.2024.04.009","url":null,"abstract":"<div><p><em>Theileria parva</em> <!-->causes East Coast fever (ECF), one of the most important and lethal tick-borne diseases of cattle in sub-Saharan Africa. ECF is a considerable burden to the livestock industry, causing annual losses exceeding US $300 million. Currently, diagnosis of <em>T. parva</em> infections relies mainly on clinical signs, serology, and microscopic identification of parasites in either blood or lymph fluid samples. However, some of these tests might not indicate ongoing infection and they all lack the sensitivity to detect low-level infections. Molecular tests such as nested and quantitative PCR assays offer high sensitivity for detection of <em>T. parva</em>. However, these tests remain highly complex technologies that are impractical to use in resource-limited settings where economic losses due to the disease have the most significant impact. A field-deployable, point-of-care test will be of significant value in the treatment and control of ECF in endemic areas. For this purpose, we have developed a CRISPR-Cas12a-based pen-side tool that can sensitively and specifically detect <em>T. parva</em> based on the p104 gene. We describe a streamlined, field-applicable diagnostic tool comprising a 20 min recombinase polymerase amplification (RPA) reaction followed by a 60 min CRISPR-Cas12a reaction using a FAM/Biotin lateral flow strip readout. We tested two different RPA primer pairs and four different CRISPR-RNAs (crRNAs). The p104-based assay displayed high sensitivity, detecting as low as one infected lymphocyte per three microliters of blood and universally detecting eight different <em>T</em>. <em>parva</em> strains without detecting DNA from other <em>Theileria</em> spp. such as <em>Theileria mutans</em> and <em>Theileria lestoquardi.</em> This work opens the way for a field-applicable diagnostic tool for the sensitive point-of-care early diagnosis of <em>T. parva</em> infections in cattle.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0020751924000791/pdfft?md5=78a5296214bd5de6acc7e548081dd6fe&pid=1-s2.0-S0020751924000791-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140770583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.1016/j.ijpara.2024.05.002
Malaria remains the most important arthropod-borne infectious disease globally. The causative agent, Plasmodium, is a unicellular eukaryote that develops inside red blood cells. Identifying new Plasmodium parasite species that infect mammalian hosts can shed light on the complex evolution and diversity of malaria parasites. Bats feature a high diversity of microorganisms including seven separate genera of malarial parasites. Three species of Plasmodium have been reported so far, for which scarce reports exist. Here we present data from an investigation of Plasmodium infections in bats in the western Guinean lowland forest in Sierra Leone. We discovered a new Plasmodium parasite in the horseshoe bat Rhinolophus landeri. Plasmodium cyclopsi infections in a member of leaf-nosed bats, Doryrhina cyclops, exhibited a high prevalence of 100%. Phylogenetic analysis of complete mitochondrial genomes and nine nuclear markers recovered a close relationship between P. cyclopsi and the new Plasmodium parasite with the rodent species Plasmodium berghei, a widely used in vivo model to study malaria in humans. The data suggests that the “rodent/bat” Plasmodium (Vinckeia) clade represents a diverse group of malarial parasites that would likely expand with a systematic sampling of small mammals in tropical Africa. Identifying the bat Plasmodium repertoire is central to our understanding of the evolution of Plasmodium parasites in mammals.
{"title":"New member of Plasmodium (Vinckeia) and Plasmodium cyclopsi discovered in bats in Sierra Leone – nuclear sequence and complete mitochondrial genome analyses","authors":"","doi":"10.1016/j.ijpara.2024.05.002","DOIUrl":"10.1016/j.ijpara.2024.05.002","url":null,"abstract":"<div><p>Malaria remains the most important arthropod-borne infectious disease globally. The causative agent, <em>Plasmodium,</em> is a unicellular eukaryote that develops inside red blood cells. Identifying new <em>Plasmodium</em> parasite species that infect mammalian hosts can shed light on the complex evolution and diversity of malaria parasites. Bats feature a high diversity of microorganisms including seven separate genera of malarial parasites. Three species of <em>Plasmodium</em> have been reported so far, for which scarce reports exist. Here we present data from an investigation of <em>Plasmodium</em> infections in bats in the western Guinean lowland forest in Sierra Leone. We discovered a new <em>Plasmodium</em> parasite in the horseshoe bat <em>Rhinolophus landeri</em>. <em>Plasmodium cyclopsi</em> infections in a member of leaf-nosed bats, <em>Doryrhina cyclops,</em> exhibited a high prevalence of 100%. Phylogenetic analysis of complete mitochondrial genomes and nine nuclear markers recovered a close relationship between <em>P. cyclopsi</em> and the new <em>Plasmodium</em> parasite with the rodent species <em>Plasmodium berghei</em>, a widely used <em>in vivo</em> model to study malaria in humans. The data suggests that the “rodent/bat” <em>Plasmodium</em> (<em>Vinckeia)</em> clade represents a diverse group of malarial parasites that would likely expand with a systematic sampling of small mammals in tropical Africa. Identifying the bat <em>Plasmodium</em> repertoire is central to our understanding of the evolution of <em>Plasmodium</em> parasites in mammals.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0020751924001085/pdfft?md5=eb2f710268bdc9cfda46e390f40e3f45&pid=1-s2.0-S0020751924001085-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140957278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.1016/j.ijpara.2024.04.005
The interaction between pathogens and vectors’ physiology can impact parasite transmission. Studying this interaction at the molecular level can help in developing control strategies. We study leishmaniases, diseases caused by Leishmania parasites transmitted by sand fly vectors, posing a significant global public health concern. Lipophosphoglycan (LPG), the major surface glycoconjugate of Leishmania, has been described to have several roles throughout the parasite’s life cycle, both in the insect and vertebrate hosts. In addition, the sand fly midgut possesses a rich microbiota expressing lipopolysaccharides (LPS). However, the effect of LPG and LPS on the gene expression of sand fly midgut proteins or immunity effectors has not yet been documented. We experimentally fed Lutzomyia longipalpis and Phlebotomus papatasi sand flies with blood containing purified LPG from Leishmania infantum, Leishmania major, or LPS from Escherichia coli. The effect on the expression of genes encoding gut proteins galectin and mucin, digestive enzymes trypsin and chymotrypsin, and antimicrobial peptides (AMPs) attacin and defensins was assessed by quantitative PCR (qPCR). The gene expression of a mucin-like protein in L. longipalpis was increased by L. infantum LPG and E. coli LPS. The gene expression of a galectin was increased in L. longipalpis by L. major LPG, and in P. papatasi by E. coli LPS. Nevertheless, the gene expression of trypsins and chymotrypsins did not significantly change. On the other hand, both L. infantum and L. major LPG significantly enhanced expression of the AMP attacin in both sand fly species and defensin in L. longipalpis. In addition, E. coli LPS increased the expression of attacin and defensin in L. longipalpis. Our study showed that Leishmania LPG and E. coli LPS differentially modulate the expression of sand fly genes involved in gut maintenance and defence. This suggests that the glycoconjugates from microbiota or Leishmania may increase the vector’s immune response and the gene expression of a gut coating protein in a permissive vector.
{"title":"Pathogen-associated molecular patterns (PAMPs) derived from Leishmania and bacteria increase gene expression of antimicrobial peptides and gut surface proteins in sand flies","authors":"","doi":"10.1016/j.ijpara.2024.04.005","DOIUrl":"10.1016/j.ijpara.2024.04.005","url":null,"abstract":"<div><p>The interaction between pathogens and vectors’ physiology can impact parasite transmission. Studying this interaction at the molecular level can help in developing control strategies. We study leishmaniases, diseases caused by <em>Leishmania</em> parasites transmitted by sand fly vectors, posing a significant global public health concern. Lipophosphoglycan (LPG), the major surface glycoconjugate of <em>Leishmania</em>, has been described to have several roles throughout the parasite’s life cycle, both in the insect and vertebrate hosts. In addition, the sand fly midgut possesses a rich microbiota expressing lipopolysaccharides (LPS). However, the effect of LPG and LPS on the gene expression of sand fly midgut proteins or immunity effectors has not yet been documented. We experimentally fed <em>Lutzomyia longipalpis</em> and <em>Phlebotomus papatasi</em> sand flies with blood containing purified LPG from <em>Leishmania infantum</em>, <em>Leishmania major</em>, or LPS from <em>Escherichia coli</em>. The effect on the expression of genes encoding gut proteins galectin and mucin, digestive enzymes trypsin and chymotrypsin, and antimicrobial peptides (AMPs) attacin and defensins was assessed by quantitative PCR (qPCR). The gene expression of a mucin-like protein in <em>L. longipalpis</em> was increased by <em>L. infantum</em> LPG and <em>E. coli</em> LPS. The gene expression of a galectin was increased in <em>L. longipalpis</em> by <em>L. major</em> LPG, and in <em>P. papatasi</em> by <em>E. coli</em> LPS. Nevertheless, the gene expression of trypsins and chymotrypsins did not significantly change. On the other hand, both <em>L. infantum</em> and <em>L. major</em> LPG significantly enhanced expression of the AMP attacin in both sand fly species and defensin in <em>L. longipalpis</em>. In addition, <em>E. coli</em> LPS increased the expression of attacin and defensin in <em>L. longipalpis</em>. Our study showed that <em>Leishmania</em> LPG and <em>E. coli</em> LPS differentially modulate the expression of sand fly genes involved in gut maintenance and defence. This suggests that the glycoconjugates from microbiota or <em>Leishmania</em> may increase the vector’s immune response and the gene expression of a gut coating protein in a permissive vector.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0020751924000754/pdfft?md5=ef1b1513e03bd7764d678541142e77e2&pid=1-s2.0-S0020751924000754-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140793675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}