International journal for parasitology最新文献

{"title":"Unconventional features in the transcription and processing of spliceosomal small nuclear RNAs in the protozoan parasite Trichomonas vaginalis","authors":"Augusto Simoes-Barbosa,&nbsp;Jully Pinheiro","doi":"10.1016/j.ijpara.2024.03.001","DOIUrl":"10.1016/j.ijpara.2024.03.001","url":null,"abstract":"<div><p><em>Trichomonas vaginalis</em> is a medically important protozoan parasite, and a deep-branching, evolutionarily divergent unicellular eukaryote that has conserved several key features of eukaryotic gene expression. <em>Trichomonas vaginalis</em> possesses a metazoan/plant-like capping apparatus, mRNAs with a cap 1 structure and spliceosomes containing the five small nuclear RNAs (snRNAs). However, in contrast to metazoan and plant snRNAs, the structurally conserved <em>T. vaginalis</em> snRNAs were initially identified as lacking the canonical guanosine cap nucleotide. To explain this unusual condition, we sought to investigate transcriptional and processing features of the spliceosomal snRNAs in this protist. Here, we show that <em>T. vaginalis</em> spliceosomal snRNA genes mostly lack typical eukaryotic promoters. In contrast to other eukaryotes, the putative TATA box in the <em>T. vaginalis</em> U6 snRNA gene was found to be dispensable for transcription or RNA polymerase selectivity. Moreover, U6 transcription in <em>T. vaginalis</em> was virtually insensitive to tagetitoxin compared with other cellular transcripts produced by the same RNA polymerase III. Most important and unexpected, snRNA transcription in <em>T. vaginalis</em> appears to bypass capping as we show that these transcripts retain their original 5′-triphosphate groups. In conclusion, transcription and processing of spliceosomal snRNAs in <em>T. vaginalis</em> deviate considerably from the conventional rules of other eukaryotes.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 6","pages":"Pages 257-266"},"PeriodicalIF":4.0,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0020751924000511/pdfft?md5=2a6e8d2f9a34cd0cc1e7460da5f9ff00&pid=1-s2.0-S0020751924000511-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140059279","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}

{"title":"Gastropod invasions in anthropogenically impacted impoundments in South Africa: Tracing their origins and exploring field evidence of parasite spillback and amplification","authors":"James Omondi Outa,&nbsp;Parthi Bhika,&nbsp;Annemariè Avenant-Oldewage","doi":"10.1016/j.ijpara.2024.02.004","DOIUrl":"10.1016/j.ijpara.2024.02.004","url":null,"abstract":"&lt;div&gt;&lt;p&gt;Invasive snails are associated with ecological problems in freshwater bodies worldwide. However, their impact on the transmission of digenean infections remain underreported. In the present study, 1708 specimens representing four snail species were sampled from four impoundments in the Limpopo River system in South Africa. &lt;em&gt;Gyraulus chinensis&lt;/em&gt; (Planorbidae), &lt;em&gt;Physella acuta&lt;/em&gt; (Physidae) and &lt;em&gt;Pseudosuccinea columella&lt;/em&gt; (Lymnaeidae), which are invasive, were found in all the sampling sites. In contrast, the native lymnaeid &lt;em&gt;Radix natalensis&lt;/em&gt; occurred at only one study site. Digeneans were observed only from &lt;em&gt;R&lt;/em&gt;. &lt;em&gt;natalensis&lt;/em&gt; (prevalence = 49%) and &lt;em&gt;Ps&lt;/em&gt;. &lt;em&gt;columella&lt;/em&gt; (prevalence = 23%). Morphological and genetic analyses revealed four digeneans: &lt;em&gt;Fasciola nyanzae&lt;/em&gt;, &lt;em&gt;Orientocreadium&lt;/em&gt; sp., &lt;em&gt;Petasiger&lt;/em&gt; sp. and &lt;em&gt;Patagifer vioscai&lt;/em&gt;. &lt;em&gt;Pseudosuccinea columella&lt;/em&gt; was infected by the four digeneans while &lt;em&gt;R&lt;/em&gt;. &lt;em&gt;natalensis&lt;/em&gt; harboured only &lt;em&gt;Orientocreadium&lt;/em&gt; sp. and &lt;em&gt;Petasiger&lt;/em&gt; sp. Partial sequences of &lt;em&gt;Orientocreadium&lt;/em&gt; sp. from the current study differed from congeners whose DNA data are available on GenBank, by p-distances of at least 1.84 and 2.2% for 28S and the internal transcribed spacer (ITS) rDNA, respectively. Phylogenetic analyses demonstrated that the present species is sister to &lt;em&gt;Orientocreadium batrachoides&lt;/em&gt;. Genetic and phylogenetic data based on 28S and ITS rDNA suggested that &lt;em&gt;Petasiger&lt;/em&gt; sp. from the present study and isolates of three unidentified &lt;em&gt;Petasiger&lt;/em&gt; spp. from Kenya, Hungary and Australia, were representatives of the same species. This is the first known report of &lt;em&gt;Orientocreadium&lt;/em&gt;, &lt;em&gt;Petasiger&lt;/em&gt; and &lt;em&gt;Patagifer&lt;/em&gt; from &lt;em&gt;Ps&lt;/em&gt;. &lt;em&gt;columella&lt;/em&gt;. The occurrence of &lt;em&gt;F&lt;/em&gt;. &lt;em&gt;nyanzae&lt;/em&gt; in &lt;em&gt;Ps&lt;/em&gt;. &lt;em&gt;columella&lt;/em&gt; indicates spillback from &lt;em&gt;R&lt;/em&gt;. &lt;em&gt;natalensis&lt;/em&gt;. These findings echo the concerns raised in previous studies about the potential role of &lt;em&gt;Ps&lt;/em&gt;. &lt;em&gt;columella&lt;/em&gt; in the amplification of digenean diseases in its introduced range. Phylogenetic analyses of partial sequences of the cytochrome &lt;em&gt;c&lt;/em&gt; oxidase subunit 1 mitochondrial gene (&lt;em&gt;cox&lt;/em&gt;1) showed multiple lineages of &lt;em&gt;Ps&lt;/em&gt;. &lt;em&gt;columella&lt;/em&gt; in North and South America. &lt;em&gt;Pseudosuccinea columella&lt;/em&gt; specimens from the present study belong to an invasive genotype that has spread globally and has been reported from Zimbabwe, Egypt, Portugal, Australia, Argentina, Colombia and New Mexico (USA). &lt;em&gt;Physella acuta&lt;/em&gt; from the current study had a stronger genetic relationship with isolates from Canada and Iceland, than with isolates from other parts of Africa, suggesting several invasion routes into Africa. This is the first known DNA characterisation of &lt;em&gt;G&lt;/em&gt;. &lt;em&gt;chinensis&lt;/em&gt; from Africa. Phylogenetic reconstruction indicated multiple exit events of &lt;","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 6","pages":"Pages 279-301"},"PeriodicalIF":4.0,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S002075192400050X/pdfft?md5=34b1f0e137f67f931d60f98b5a5ed96a&pid=1-s2.0-S002075192400050X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140059306","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}

{"title":"The oceanic pleuston community as a potentially crucial life-cycle pathway for pelagic fish-infecting parasitic worms","authors":"Clarisse Louvard ,&nbsp;Russell Q.-Y. Yong ,&nbsp;Scott C. Cutmore ,&nbsp;Thomas H. Cribb","doi":"10.1016/j.ijpara.2023.11.001","DOIUrl":"10.1016/j.ijpara.2023.11.001","url":null,"abstract":"<div><p>Pleustonic organisms form an important part of pelagic ecosystems by contributing to pelagic trophic chains and supporting connectivity between oceanic habitats. This study systematically analysed the trematode community harboured by pleustonic molluscs and cnidarians from offshore Queensland, Australia. Four mollusc and three cnidarian species were collected from beaches of North Stradbroke Island, Queensland. Two mollusc species and all three cnidarians harboured large numbers of hemiuroid metacercariae (Trematoda: Hemiuroidea). Eight taxa from four hemiuroid families (Accacoeliidae, Didymozoidae, Hemiuridae and Sclerodistomidae) were distinguished via molecular sequencing. Four of those taxa were identified to species. All trematode taxa except one didymozoid were shared by two or more host species; five species occurred in both gastropods and cnidarians. It is hypothesised that the life-cycles of these hemiuroids are highly plastic, involving multiple opportunistic pathways of metacercarial transmission to the definitive hosts. Transmission and the use of pleuston by hemiuroids likely varies with sea surface use and ontogenetic trophic shifts of apex predators. The small number of trematode species found in pleuston is consistent with significant ecological specificity, and the inference that other pelagic trematodes use alternative pathways of transmission that do not involve pleustonic organisms. Such pathways may involve i) pelagic hosts exclusively; ii) benthic or demersal hosts exclusively, consumed by apex predators during their dives; or iii) both benthic and pelagic hosts in transmission chains dependent on vertical migrations of prey. The influence of the connectivity of open-ocean ecosystems on parasite transmission is identified as an area in critical need of research.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 6","pages":"Pages 267-278"},"PeriodicalIF":4.0,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0020751923002060/pdfft?md5=9b6490b903a1d47ffb35ccd1a359ea49&pid=1-s2.0-S0020751923002060-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136397311","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}

{"title":"First use of tissue exudate serology to identify Toxocara spp. infection in food animals","authors":"Sara R. Healy ,&nbsp;Eric R. Morgan ,&nbsp;Joaquin M. Prada ,&nbsp;Grégory Karadjian ,&nbsp;Aurélie Chevillot ,&nbsp;Martha Betson","doi":"10.1016/j.ijpara.2024.02.003","DOIUrl":"10.1016/j.ijpara.2024.02.003","url":null,"abstract":"<div><p><em>Toxocara canis</em> and <em>Toxocara cati</em> are globally distributed, zoonotic roundworm parasites. Human infection can have serious clinical consequences including blindness and brain disorders. In addition to ingesting environmental eggs, humans can become infected by eating infective larvae in raw or undercooked meat products. To date, no studies have assessed the prevalence of <em>Toxocara</em> spp. larvae in meat from animals consumed as food in the UK or assessed tissue exudates for the presence of anti-<em>Toxocara</em> antibodies. This study aimed to assess the potential risk to consumers eating meat products from animals infected with <em>Toxocara</em> spp. Tissue samples were obtained from 155 different food producing animals in the south, southwest and east of England, UK. Tissue samples (<em>n</em> = 226), either muscle or liver, were processed by artificial digestion followed by microscopic sediment evaluation for <em>Toxocara</em> spp. larvae, and tissue exudate samples (<em>n</em> = 141) were tested for the presence of anti-<em>Toxocara</em> antibodies using a commercial ELISA kit. A logistic regression model was used to compare anti-<em>Toxocara</em> antibody prevalence by host species, tissue type and source. While no larvae were found by microscopic examination after tissue digestion, the overall prevalence of anti-<em>Toxocara</em> antibodies in tissue exudates was 27.7%. By species, 35.3% of cattle (<em>n</em> = 34), 15.0% of sheep (<em>n</em> = 60), 54.6% of goats (<em>n</em> = 11) and 61.1% of pigs (<em>n</em> = 18) had anti-<em>Toxocara</em> antibodies. Logistic regression analysis found pigs were more likely to be positive for anti-<em>Toxocara</em> antibodies (odds ration (OR) = 2.89, <em>P</em> = 0.0786) compared with the other species sampled but only at a 10% significance level. The high prevalence of anti-<em>Toxocara</em> antibodies in tissue exudates suggests that exposure of food animals to this parasite is common in England. Tissue exudate serology on meat products within the human food chain could be applied in support of food safety and to identify practices that increase risks of foodborne transmission of zoonotic toxocariasis.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 6","pages":"Pages 303-310"},"PeriodicalIF":4.0,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0020751924000481/pdfft?md5=b7808135a0002430b2ff5a3381312fee&pid=1-s2.0-S0020751924000481-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140065184","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}

{"title":"Temperature-bounded development of Dirofilaria immitis larvae restricts the geographical distribution and seasonality of its transmission: case study and decision support system for canine heartworm management in Australia","authors":"Peter J. Atkinson ,&nbsp;Mark Stevenson ,&nbsp;Ryan O'Handley ,&nbsp;Torben Nielsen ,&nbsp;Charles G.B. Caraguel","doi":"10.1016/j.ijpara.2024.02.001","DOIUrl":"10.1016/j.ijpara.2024.02.001","url":null,"abstract":"<div><p><em>Dirofilaria immitis</em> is the causative agent of canine heartworm disease. We used the established heartworm development unit (HDU) principle to map the extrinsic incubation period (EIP) of <em>D. immitis</em> in Australia using historical weather data from 2013–2022. We found weather conditions suitable for EIP completion showed substantial seasonality and geographical variability. Whilst a considerable percentage of the Australian territory showed suitable weather conditions to always support EIP completion (17%), only 2.7% of the 2021 Australian human population lived in this region. Therefore, 97% of the population lived in an area that changed its EIP suitability within the study period. EIP completion is required prior to <em>D. immitis</em> transmission, meaning that infection risk of <em>D. immitis</em> is seasonal and location-dependent, being disrupted each year for most of the human population’s dogs. We developed an online, open access tool allowing us to visualise EIP completion across Australia historically and in near real-time. We aim to support veterinarians to make risk-based recommendations for dirofilariosis prevention by using the tool, available at <span>https://heartworm-mapping.adelaide.edu.au/shiny/</span><svg><path></path></svg>.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 6","pages":"Pages 311-319"},"PeriodicalIF":4.0,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S002075192400047X/pdfft?md5=69d21169a4ae16642f3c3ed6a6323d45&pid=1-s2.0-S002075192400047X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140049408","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}

{"title":"Intricate balance of dually-localized catalase modulates infectivity of Leptomonas seymouri (Kinetoplastea: Trypanosomatidae)","authors":"Ľubomíra Chmelová ,&nbsp;Natalya Kraeva ,&nbsp;Andreu Saura ,&nbsp;Adam Krayzel ,&nbsp;Cecilia Stahl Vieira ,&nbsp;Tainá Neves Ferreira ,&nbsp;Rodrigo Pedro Soares ,&nbsp;Barbora Bučková ,&nbsp;Arnau Galan ,&nbsp;Eva Horáková ,&nbsp;Barbora Vojtková ,&nbsp;Jovana Sádlová ,&nbsp;Marina N. Malysheva ,&nbsp;Anzhelika Butenko ,&nbsp;Galina Prokopchuk ,&nbsp;Alexander O. Frolov ,&nbsp;Julius Lukeš ,&nbsp;Anton Horváth ,&nbsp;Ingrid Škodová-Sveráková ,&nbsp;Denise Feder ,&nbsp;Vyacheslav Yurchenko","doi":"10.1016/j.ijpara.2024.04.007","DOIUrl":"10.1016/j.ijpara.2024.04.007","url":null,"abstract":"<div><p>Nearly all aerobic organisms are equipped with catalases, powerful enzymes scavenging hydrogen peroxide and facilitating defense against harmful reactive oxygen species. In trypanosomatids, this enzyme was not present in the common ancestor, yet it had been independently acquired by different lineages of monoxenous trypanosomatids from different bacteria at least three times. This observation posited an obvious question: why was catalase so “sought after” if many trypanosomatid groups do just fine without it? In this work, we analyzed subcellular localization and function of catalase in <em>Leptomonas seymouri</em>. We demonstrated that this enzyme is present in the cytoplasm and a subset of glycosomes, and that its cytoplasmic retention is H₂O₂-dependent. The ablation of catalase in this parasite is not detrimental in vivo, while its overexpression resulted in a substantially higher parasite load in the experimental infection of <em>Dysdercus peruvianus</em>. We propose that the capacity of studied flagellates to modulate the catalase activity in the midgut of its insect host facilitates their development and protects them from oxidative damage at elevated temperatures.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 8","pages":"Pages 391-400"},"PeriodicalIF":4.0,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0020751924000778/pdfft?md5=441d21891e548dfcb69956b13122b010&pid=1-s2.0-S0020751924000778-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140787749","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}

{"title":"The geographic limits and life history of the tropical brown dog tick, Rhipicephalus linnaei (Audouin, 1826), in Australia with notes on the spread of Ehrlichia canis","authors":"Ernest J.M. Teo ,&nbsp;Kimberly L. Evasco ,&nbsp;Dayana Barker ,&nbsp;M.L. Levin ,&nbsp;Stephen C. Barker","doi":"10.1016/j.ijpara.2024.04.004","DOIUrl":"10.1016/j.ijpara.2024.04.004","url":null,"abstract":"<div><p>The tropical brown dog tick, <em>Rhipicephalus linnaei</em>, is a tick of much medical, veterinary, and zoonotic importance. This tick has a nearly world-wide distribution due to its ability to survive and propagate in kennels and houses. <em>Rhipicephalus linnaei</em> is the vector of <em>Ehrlichia canis</em>, the causative agent of canine monocytic ehrlichiosis, an often debilitating disease of canids and, occasionally, humans. To prevent incursion of <em>E. canis</em> into Australia, dogs entering Australia have been required to have a negative immunofluorescence antibody test for <em>E. canis</em>. In May 2020 however, <em>E. canis</em> was detected in Western Australia. The detection of <em>E. canis</em> in Australia prompted disease investigation and concerted surveillance for <em>R. linnaei</em> and <em>E. canis</em> in regions across Australia. These investigations revealed that <em>R. linnaei</em> was established far beyond the previously recognised geographic range limits of this tick. In the present paper, using records from various collections, published data, and data from our network of veterinarian collaborators and colleagues, we update the current geographic range of <em>R. linnaei</em> in Australia. Our analyses revealed that the geographic range of <em>R. linnaei</em> in Australia is much wider than was previously supposed, particularly in Western Australia, and in South Australia. We also map, for the first time, where <em>E. canis</em> has been detected in Australia. Last, we discuss the possible routes of incursion and subsequently the factors which may have aided the spread of <em>E. canis</em> in Australia which led to the establishment of this pathogen in Australia.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 8","pages":"Pages 453-462"},"PeriodicalIF":4.0,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0020751924000742/pdfft?md5=09d5282294cf0dde2a227896b0e3a67b&pid=1-s2.0-S0020751924000742-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140782195","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}

{"title":"Epidemiological investigation of Entamoeba in wild rhesus macaques in China: A novel ribosomal lineage and genetic differentiation of Entamoeba nuttalli","authors":"Mengshi Yu ,&nbsp;Yongfang Yao ,&nbsp;Xin Li ,&nbsp;Aoxing Su ,&nbsp;Meng Xie ,&nbsp;Ying Xiong ,&nbsp;Shengzhi Yang ,&nbsp;Qingyong Ni ,&nbsp;Hongtao Xiao ,&nbsp;Huailiang Xu","doi":"10.1016/j.ijpara.2024.04.002","DOIUrl":"10.1016/j.ijpara.2024.04.002","url":null,"abstract":"<div><p>Wild rhesus macaques are a potential source of zoonotic parasites for humans, and <em>Entamoeba</em> spp. are common intestinal parasites. To investigate the prevalence of <em>Entamoeba</em> in wild rhesus macaques in China and explore the genetic differentiation of the potentially pathogenic species Entamoeba nuttalli, a total of 276 fecal samples from five populations at high altitudes (HAG, 2,800–4,100 m above sea level) and four populations at low altitudes (LAG, 5–1,000 m above sea level) were collected. PCR methods based on the ssrRNA gene were used to detect <em>Entamoeba</em> infection. Genotyping of E. nuttalli was performed based on six tRNA-linked short tandem repeat (STR) loci for further genetic analyses. The results revealed that <em>Entamoeba</em> infection (69.2%) was common in wild rhesus macaques in China, especially in LAG which had a significantly higher prevalence rate than that in HAG (<em>P</em> &lt; 0.001). Three zoonotic species were identified: <em>Entamoeba chattoni</em> (60.9%) was the most prevalent species and distributed in all the populations, followed by <em>Entamoeba coli</em> (33.3%) and <em>Entamoeba nuttalli</em> (17.4%). In addition, a novel <em>Entamoeba</em> ribosomal lineage named RL13 (22.8%) was identified, and phylogenetic analysis revealed a close genetic relationship between RL13 and <em>Entamoeba. hartmanni</em>. Genotyping of <em>E. nuttalli</em> obtained 24 genotypes from five populations and further analysis showed <em>E. nuttalli</em> had a high degree of genetic differentiation (F_ST &gt; 0.25, Nm &lt; 1) between the host populations. The result of analysis of molecular variance (AMOVA) revealed that observed genetic differences mainly originate from differences among populations (F_ST = 0.91). Meanwhile, the phylogenetic tree showed that these genotypes of <em>E. nuttalli</em> were clustered according to geographical populations, indicating a significant phylogeographic distribution pattern. Considering the potential pathogenicity of <em>E. nuttalli</em>, attention should be paid to its risk of zoonotic transmission.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 8","pages":"Pages 441-451"},"PeriodicalIF":4.0,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140623088","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}

{"title":"Effects of regional coordination of salmon louse control in reducing negative impacts of salmonid aquaculture on wild salmonids","authors":"Leif Christian Stige ,&nbsp;Peder A. Jansen ,&nbsp;Kari O. Helgesen","doi":"10.1016/j.ijpara.2024.04.003","DOIUrl":"10.1016/j.ijpara.2024.04.003","url":null,"abstract":"<div><p>Parasitic salmon lice (<em>Lepeophtheirus salmonis</em>) are a constraint to the sustainable growth of salmonids in open net pens, and this issue has caused production to level off in recent years in the most aquaculture-intensive areas of Norway. The maximum allowed biomass at a regional level is regulated by using the so-called “traffic light” system, where salmon louse-induced mortality of migrating wild salmon post-smolts is evaluated against set targets. As a case study, we have investigated how a specific aquaculture-intensive area can reduce its louse levels sufficiently to achieve a low impact on wild salmon. Analyses of the output from a virtual post-smolt model that uses data on the reported number of salmon lice in fish farms as key input data and estimates the salmon louse-induced mortality of wild out-migrating Atlantic salmon post-smolts, suggested that female louse abundance on the local farms must be halved in spring to reach the goal implied by the traffic light system. The outcome of a modelling scenario simulating a proposed new plan for coordinated production and fallowing proved beneficial, with an overall reduction in louse infestations and treatment efforts. The interannual variability in louse abundance in spring, however, increased for this scenario, implying unacceptably high louse abundance when many farms were in their second production year. We then combined the scenario with coordinated production with other louse control measures. Only measures that reduced the density of farmed salmonids in open cages in the study area resulted in reductions in salmon louse infestations to acceptable levels. This could be achieved either by stocking with larger fish to reduce exposure time or by reducing fish numbers, e.g. by producing in closed units.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 8","pages":"Pages 463-474"},"PeriodicalIF":4.0,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0020751924000730/pdfft?md5=462d54e56a55ac34252dcfd4fa0c45c7&pid=1-s2.0-S0020751924000730-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140779866","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}

{"title":"Searching for common patterns in parasite ecology: species and host contributions to beta-diversity in helminths of South African ungulates and fleas of South American rodents","authors":"Ivan G. Horak ,&nbsp;Joop Boomker ,&nbsp;Vasily I. Grabovsky ,&nbsp;Irina S. Khokhlova ,&nbsp;Kerstin Junker ,&nbsp;Juliana P. Sanchez ,&nbsp;M. Fernanda López Berrizbeitia ,&nbsp;Boris R. Krasnov","doi":"10.1016/j.ijpara.2024.04.001","DOIUrl":"10.1016/j.ijpara.2024.04.001","url":null,"abstract":"<div><p>We searched for common patterns in parasite ecology by investigating species and host contributions to the beta-diversity of infracommunities (=assemblages of parasites harboured by a host individual) in helminths of three species of South African ungulates and fleas of 11 species of South American rodents, assuming that a comparison of patterns in distinctly different parasites and hosts would allow us to judge the generality or, at least, commonness of these patterns. We used data on species’ composition and numbers of parasites and asked whether (i) parasite species’ attributes (life cycle, transmission mode, and host specificity in helminths; possession of sclerotized combs, microhabitat preference, and host specificity in fleas) or their population structure (mean abundance and/or prevalence) and (ii) host characteristics (sex and age) affect parasite and host species’ contributions to parasite beta-diversity (SCBD and HCBD, respectively). We found that parasite species’ morphological and ecological attributes were mostly not associated with their SCBD. In contrast, parasite SCBD, in both ungulates and rodents, significantly increased with either parasite mean abundance or prevalence or both. The effect of host characteristics on HCBD was detected in a few hosts only. In general, parasite infracommunities’ beta-diversity appeared to be driven by variation in parasite species rather than the uniqueness of the assemblages harboured by individual hosts. We conclude that some ecological patterns (such as the relationships between SCBD and parasite abundance/prevalence) appear to be common and do not differ between different host-parasite associations in different geographic regions, whereas other patterns (the relationships between SCBD and parasite species’ attributes) are contingent and depend on parasite and host identities.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 8","pages":"Pages 429-439"},"PeriodicalIF":4.0,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140623213","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}