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Unconventional features in the transcription and processing of spliceosomal small nuclear RNAs in the protozoan parasite Trichomonas vaginalis 阴道毛滴虫原生寄生虫中剪接体小核 RNA 的转录和处理过程中的非常规特征。
IF 4 2区 医学 Q1 PARASITOLOGY Pub Date : 2024-05-01 DOI: 10.1016/j.ijpara.2024.03.001
Augusto Simoes-Barbosa, Jully Pinheiro

Trichomonas vaginalis is a medically important protozoan parasite, and a deep-branching, evolutionarily divergent unicellular eukaryote that has conserved several key features of eukaryotic gene expression. Trichomonas vaginalis 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 T. vaginalis 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 T. vaginalis spliceosomal snRNA genes mostly lack typical eukaryotic promoters. In contrast to other eukaryotes, the putative TATA box in the T. vaginalis U6 snRNA gene was found to be dispensable for transcription or RNA polymerase selectivity. Moreover, U6 transcription in T. vaginalis was virtually insensitive to tagetitoxin compared with other cellular transcripts produced by the same RNA polymerase III. Most important and unexpected, snRNA transcription in T. vaginalis 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 T. vaginalis deviate considerably from the conventional rules of other eukaryotes.

阴道毛滴虫是一种在医学上非常重要的原生动物寄生虫,也是一种深分支、进化分化的单细胞真核生物,它保留了真核生物基因表达的几个关键特征。阴道毛滴虫具有类似于元祖/植物的封盖装置、具有帽 1 结构的 mRNA 和含有五种小核 RNA(snRNA)的剪接体。然而,与类囊动物和植物的 snRNAs 不同,结构上保守的阴道球菌 snRNAs 最初被鉴定为缺乏典型的鸟苷酸帽核苷酸。为了解释这种不寻常的情况,我们试图研究这种原生动物中剪接体 snRNA 的转录和加工特征。在这里,我们发现阴道蝇的剪接体 snRNA 基因大多缺乏典型的真核生物启动子。与其他真核生物不同的是,我们发现阴道蝇 U6 snRNA 基因中的假定 TATA 框对于转录或 RNA 聚合酶选择性来说是不可或缺的。此外,与由相同的 RNA 聚合酶 III 产生的其他细胞转录本相比,阴道球菌的 U6 转录对 tagetitoxin 几乎不敏感。最重要也是最出乎意料的是,阴道球菌的 snRNA 转录似乎绕过了封顶,因为我们发现这些转录本保留了其原始的 5'-三磷酸基团。总之,阴道球菌中剪接体 snRNA 的转录和处理大大偏离了其他真核生物的传统规则。
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引用次数: 0
Gastropod invasions in anthropogenically impacted impoundments in South Africa: Tracing their origins and exploring field evidence of parasite spillback and amplification 南非受人为影响的蓄水池中的腹足类入侵:追溯其起源并探索寄生虫回溢和放大的实地证据。
IF 4 2区 医学 Q1 PARASITOLOGY Pub Date : 2024-05-01 DOI: 10.1016/j.ijpara.2024.02.004
James Omondi Outa, Parthi Bhika, Annemariè Avenant-Oldewage
<div><p>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. <em>Gyraulus chinensis</em> (Planorbidae), <em>Physella acuta</em> (Physidae) and <em>Pseudosuccinea columella</em> (Lymnaeidae), which are invasive, were found in all the sampling sites. In contrast, the native lymnaeid <em>Radix natalensis</em> occurred at only one study site. Digeneans were observed only from <em>R</em>. <em>natalensis</em> (prevalence = 49%) and <em>Ps</em>. <em>columella</em> (prevalence = 23%). Morphological and genetic analyses revealed four digeneans: <em>Fasciola nyanzae</em>, <em>Orientocreadium</em> sp., <em>Petasiger</em> sp. and <em>Patagifer vioscai</em>. <em>Pseudosuccinea columella</em> was infected by the four digeneans while <em>R</em>. <em>natalensis</em> harboured only <em>Orientocreadium</em> sp. and <em>Petasiger</em> sp. Partial sequences of <em>Orientocreadium</em> 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 <em>Orientocreadium batrachoides</em>. Genetic and phylogenetic data based on 28S and ITS rDNA suggested that <em>Petasiger</em> sp. from the present study and isolates of three unidentified <em>Petasiger</em> spp. from Kenya, Hungary and Australia, were representatives of the same species. This is the first known report of <em>Orientocreadium</em>, <em>Petasiger</em> and <em>Patagifer</em> from <em>Ps</em>. <em>columella</em>. The occurrence of <em>F</em>. <em>nyanzae</em> in <em>Ps</em>. <em>columella</em> indicates spillback from <em>R</em>. <em>natalensis</em>. These findings echo the concerns raised in previous studies about the potential role of <em>Ps</em>. <em>columella</em> in the amplification of digenean diseases in its introduced range. Phylogenetic analyses of partial sequences of the cytochrome <em>c</em> oxidase subunit 1 mitochondrial gene (<em>cox</em>1) showed multiple lineages of <em>Ps</em>. <em>columella</em> in North and South America. <em>Pseudosuccinea columella</em> 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). <em>Physella acuta</em> 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 <em>G</em>. <em>chinensis</em> from Africa. Phylogenetic reconstruction indicated multiple exit events of <
入侵蜗牛与全球淡水水体的生态问题有关。然而,它们对地衣类传染病传播的影响仍未得到充分报道。本研究从南非林波波河水系的四个蓄水池中采集了 1708 个标本,代表了四个蜗牛物种。在所有取样地点都发现了外来蜗牛--Gyraulus chinensis(Planorbidae)、Physella acuta(Physidae)和Pseudosuccinea columella(Lymnaeidae)。相比之下,仅在一个研究地点发现了原生的裸鲤。仅在 R. natalensis(发生率 = 49%)和 Ps. columella(发生率 = 23%)中观察到 Digeneans。形态学和遗传学分析发现了四种地衣:Fasciola nyanzae、Orientocreadium sp.、Petasiger sp.和 Patagifer vioscai。本研究中的 Orientocreadium sp.部分序列与 GenBank 上有 DNA 数据的同系物的 28S 和内部转录间隔(ITS)rDNA 的 p 差至少分别为 1.84% 和 2.2%。系统进化分析表明,该物种与蝙蝠螯合蟾蜍(Orientocreadium batrachoides)是姊妹物种。基于 28S 和 ITS rDNA 的遗传和系统发育数据表明,本研究中的 Petasiger sp.与来自肯尼亚、匈牙利和澳大利亚的三个未确定的 Petasiger spp.是同一物种的代表。这是第一份已知的从 columella Ps.中发现 Orientocreadium、Petasiger 和 Patagifer 的报告。F. nyanzae 在 Ps. columella 中的出现表明其是从 R. natalensis 中溢出的。这些研究结果与之前的研究结果一致,即在引入地区,Ps. columella 在扩大地衣病的潜在作用。细胞色素 c 氧化酶亚单位 1 线粒体基因(cox1)部分序列的系统发生分析表明,Ps. columella 在北美和南美有多个品系。本研究中的 Pseudosuccinea columella 标本属于入侵基因型,该基因型已扩散到全球,津巴布韦、埃及、葡萄牙、澳大利亚、阿根廷、哥伦比亚和新墨西哥(美国)均有报道。与非洲其他地区的分离物相比,本研究中的Physella acuta与加拿大和冰岛分离物的遗传关系更为密切,这表明有几条入侵非洲的路线。这是首次对非洲的 G. chinensis 进行 DNA 鉴定。系统发育重建表明,G. chinensis 从亚洲多次进入欧洲和非洲。南非的分离株聚集在一个最近的分支中,该分支包含来自捷克共和国和中国香港的分离株。考虑到入侵蜗牛出现在本研究的所有取样地点,有必要调查促进其建立的因素,并监测其对本地蜗牛种群的影响。
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引用次数: 0
The oceanic pleuston community as a potentially crucial life-cycle pathway for pelagic fish-infecting parasitic worms 海洋菌群作为中上层鱼类感染寄生虫的潜在关键生命周期途径。
IF 4 2区 医学 Q1 PARASITOLOGY Pub Date : 2024-05-01 DOI: 10.1016/j.ijpara.2023.11.001
Clarisse Louvard , Russell Q.-Y. Yong , Scott C. Cutmore , Thomas H. Cribb

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.

浮游生物是中上层生态系统的重要组成部分,有助于形成中上层营养链,并支持海洋栖息地之间的连通性。本研究系统地分析了澳大利亚昆士兰州近海的冻疮软体动物和刺胞动物所携带的吸虫群落。在昆士兰北斯特拉德布鲁克岛的海滩上采集了四种软体动物和三种刺胞动物。两种软体动物和所有三种刺胞动物都含有大量的半类囊蚴(水螅目:半类总科)。通过分子序列分析,鉴定出4个半足科8个类群(棘足科、棘足科、半足科和棘足科)。其中4个分类群被鉴定为种。除一种双虫外,所有吸虫类群均为两个或多个寄主共有;腹足动物和刺胞动物均有5种。据推测,这些半尿样细胞的生命周期具有高度可塑性,涉及到囊蚴传播到最终宿主的多种机会性途径。半水生生物对浮游生物的传播和利用可能随着海洋表面的利用和顶端捕食者的个体发育营养变化而变化。在衣原体中发现的吸虫种类很少,这与显著的生态特异性是一致的,并且推断其他远洋吸虫使用不涉及衣原体生物的替代传播途径。这种途径可能只涉及i)远洋寄主;Ii)底栖或底栖寄主,在潜水时被顶端捕食者吃掉;或iii)依赖于猎物垂直迁移的传播链中的底栖和远洋宿主。开放海洋生态系统连通性对寄生虫传播的影响被确定为迫切需要研究的领域。
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引用次数: 0
First use of tissue exudate serology to identify Toxocara spp. infection in food animals 首次利用组织渗出物血清学鉴定食用动物的弓形虫感染。
IF 4 2区 医学 Q1 PARASITOLOGY Pub Date : 2024-05-01 DOI: 10.1016/j.ijpara.2024.02.003
Sara R. Healy , Eric R. Morgan , Joaquin M. Prada , Grégory Karadjian , Aurélie Chevillot , Martha Betson

Toxocara canis and Toxocara cati 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 Toxocara spp. larvae in meat from animals consumed as food in the UK or assessed tissue exudates for the presence of anti-Toxocara antibodies. This study aimed to assess the potential risk to consumers eating meat products from animals infected with Toxocara spp. Tissue samples were obtained from 155 different food producing animals in the south, southwest and east of England, UK. Tissue samples (n = 226), either muscle or liver, were processed by artificial digestion followed by microscopic sediment evaluation for Toxocara spp. larvae, and tissue exudate samples (n = 141) were tested for the presence of anti-Toxocara antibodies using a commercial ELISA kit. A logistic regression model was used to compare anti-Toxocara 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-Toxocara antibodies in tissue exudates was 27.7%. By species, 35.3% of cattle (n = 34), 15.0% of sheep (n = 60), 54.6% of goats (n = 11) and 61.1% of pigs (n = 18) had anti-Toxocara antibodies. Logistic regression analysis found pigs were more likely to be positive for anti-Toxocara antibodies (odds ration (OR) = 2.89, P = 0.0786) compared with the other species sampled but only at a 10% significance level. The high prevalence of anti-Toxocara 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.

犬弓形虫(Toxocara canis)和猫弓形虫(Toxocara cati)是分布于全球的人畜共患蛔虫寄生虫。人类感染后会产生严重的临床后果,包括失明和脑部疾病。除了摄入环境中的虫卵外,人类还可能通过食用生肉或未煮熟的肉制品中的感染性幼虫而受到感染。迄今为止,还没有任何研究对英国作为食物食用的动物肉类中的弓形虫幼虫流行率进行评估,或对组织渗出物中是否存在抗弓形虫抗体进行评估。这项研究旨在评估消费者食用感染弓形虫的动物肉制品的潜在风险。组织样本(226 份)取自英国英格兰南部、西南部和东部的 155 种不同的食用动物。对肌肉或肝脏组织样本(226 份)进行人工消化处理,然后用显微镜对沉淀物进行评估,以检测是否存在弓形虫幼虫,并使用商业 ELISA 试剂盒对组织渗出物样本(141 份)进行检测,以检测是否存在抗弓形虫抗体。使用逻辑回归模型比较宿主种类、组织类型和来源的抗毒原虫抗体流行率。组织消化后经显微镜检查未发现幼虫,但组织渗出物中抗弓形虫抗体的总体流行率为 27.7%。按物种划分,35.3% 的牛(34 头)、15.0% 的绵羊(60 头)、54.6% 的山羊(11 头)和 61.1% 的猪(18 头)有抗弓形虫抗体。逻辑回归分析发现,与其他采样物种相比,猪的抗毒原虫抗体呈阳性的几率更高(几率比(OR)=2.89,P=0.0786),但只有10%的显著性水平。组织渗出物中抗弓形虫抗体的高流行率表明,食用动物接触这种寄生虫在英格兰很常见。可以对人类食物链中的肉类产品进行组织渗出物血清学检测,以支持食品安全,并确定哪些做法会增加人畜共患弓形虫病经食物传播的风险。
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引用次数: 0
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 温限性潜伏二鞭毛虫幼虫的发育限制了其传播的地理分布和季节性:澳大利亚犬心丝虫管理的案例研究和决策支持系统。
IF 4 2区 医学 Q1 PARASITOLOGY Pub Date : 2024-05-01 DOI: 10.1016/j.ijpara.2024.02.001
Peter J. Atkinson , Mark Stevenson , Ryan O'Handley , Torben Nielsen , Charles G.B. Caraguel

Dirofilaria immitis 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 D. immitis 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 D. immitis transmission, meaning that infection risk of D. immitis 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 https://heartworm-mapping.adelaide.edu.au/shiny/.

水飞蓟马是犬心丝虫病的病原体。我们利用已建立的心丝虫发育单位(HDU)原理,使用 2013-2022 年的历史天气数据绘制了澳大利亚的白喉螺虫体外潜伏期(EIP)图。我们发现,适合完成 EIP 的天气条件具有很大的季节性和地域差异性。虽然澳大利亚境内有相当大比例的地区(17%)显示出始终支持 EIP 完成的适宜天气条件,但 2021 年澳大利亚仅有 2.7% 的人口生活在这一地区。因此,97% 的人口所居住的地区在研究期内改变了其 EIP 适宜性。在白喉螺菌传播之前,必须完成 EIP,这意味着白喉螺菌的感染风险具有季节性和地点依赖性,对于人类人口中的大多数狗来说,每年都会受到干扰。我们开发了一个在线开放访问工具,使我们能够近乎实时地直观了解澳大利亚各地的 EIP 完成情况。我们的目标是支持兽医通过使用该工具(可在 https://heartworm-mapping.adelaide.edu.au/shiny/ 上获取),为预防二螺旋体病提出基于风险的建议。注:与本文相关的补充数据。
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引用次数: 0
Intricate balance of dually-localized catalase modulates infectivity of Leptomonas seymouri (Kinetoplastea: Trypanosomatidae) 双定位过氧化氢酶的复杂平衡调节了西摩里钩端螺旋体(Kinetoplastea: Trypanosomatidae)的感染性。
IF 4 2区 医学 Q1 PARASITOLOGY Pub Date : 2024-04-23 DOI: 10.1016/j.ijpara.2024.04.007
Ľubomíra Chmelová , Natalya Kraeva , Andreu Saura , Adam Krayzel , Cecilia Stahl Vieira , Tainá Neves Ferreira , Rodrigo Pedro Soares , Barbora Bučková , Arnau Galan , Eva Horáková , Barbora Vojtková , Jovana Sádlová , Marina N. Malysheva , Anzhelika Butenko , Galina Prokopchuk , Alexander O. Frolov , Julius Lukeš , Anton Horváth , Ingrid Škodová-Sveráková , Denise Feder , Vyacheslav Yurchenko

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 Leptomonas seymouri. 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 Dysdercus peruvianus. 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.

几乎所有需氧生物都具有过氧化氢酶,这是一种清除过氧化氢的强力酶,有助于抵御有害的活性氧。在锥虫的共同祖先中并不存在这种酶,但单细胞锥虫的不同品系至少三次从不同细菌中独立获得了这种酶。这一观察结果提出了一个显而易见的问题:既然许多锥虫类群在没有过氧化氢酶的情况下也能正常工作,为什么过氧化氢酶会如此 "抢手 "呢?在这项工作中,我们分析了过氧化氢酶在赛毛氏钩端螺旋体中的亚细胞定位和功能。我们证明,这种酶存在于细胞质和糖体的一个子集中,而且它在细胞质中的保留是依赖于 H2O2 的。这种寄生虫体内过氧化氢酶的消减不会对其造成危害,而过量表达过氧化氢酶则会在秘鲁痢疾杆菌的实验感染中导致寄生虫数量大幅增加。我们认为,所研究的鞭毛虫能够调节昆虫宿主中肠中过氧化氢酶的活性,这有利于它们的发育,并保护它们在高温下免受氧化损伤。
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引用次数: 0
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 澳大利亚热带褐狗蜱 Rhipicephalus linnaei(Audouin,1826 年)的地理范围和生活史,以及犬艾氏菌的传播情况。
IF 4 2区 医学 Q1 PARASITOLOGY Pub Date : 2024-04-11 DOI: 10.1016/j.ijpara.2024.04.004
Ernest J.M. Teo , Kimberly L. Evasco , Dayana Barker , M.L. Levin , Stephen C. Barker

The tropical brown dog tick, Rhipicephalus linnaei, 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. Rhipicephalus linnaei is the vector of Ehrlichia canis, the causative agent of canine monocytic ehrlichiosis, an often debilitating disease of canids and, occasionally, humans. To prevent incursion of E. canis into Australia, dogs entering Australia have been required to have a negative immunofluorescence antibody test for E. canis. In May 2020 however, E. canis was detected in Western Australia. The detection of E. canis in Australia prompted disease investigation and concerted surveillance for R. linnaei and E. canis in regions across Australia. These investigations revealed that R. linnaei 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 R. linnaei in Australia. Our analyses revealed that the geographic range of R. linnaei 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 E. canis has been detected in Australia. Last, we discuss the possible routes of incursion and subsequently the factors which may have aided the spread of E. canis in Australia which led to the establishment of this pathogen in Australia.

热带褐狗蜱(Rhipicephalus linnaei)是一种在医疗、兽医和人畜共患病方面具有重要意义的蜱虫。这种蜱虫几乎遍布全球,因为它能够在狗窝和房屋中生存和繁殖。Rhipicephalus linnaei 是犬单核细胞埃希氏菌的病媒,犬单核细胞埃希氏菌病通常是一种使犬衰弱的疾病,偶尔也会传染给人类。为防止犬科埃希氏菌侵入澳大利亚,进入澳大利亚的犬只必须通过犬科埃希氏菌免疫荧光抗体检测呈阴性。但在 2020 年 5 月,西澳大利亚州检测到犬大肠杆菌。在澳大利亚检测到犬大肠杆菌后,澳大利亚各地区开展了疾病调查,并对R. linnaei和犬大肠杆菌进行了协同监测。这些调查显示,R. linnaei 的分布范围远远超出了这种蜱虫之前被认可的地理范围。在本文中,我们利用各种收集的记录、公开发表的数据以及我们的兽医合作者和同事网络提供的数据,更新了目前 R. linnaei 在澳大利亚的地理分布范围。我们的分析表明,R. linnaei 在澳大利亚的地理分布范围比以前想象的要广得多,尤其是在西澳大利亚州和南澳大利亚州。我们还首次绘制了在澳大利亚发现犬伊蚊的地区分布图。最后,我们讨论了E. canis可能的入侵路线,以及随后可能帮助E. canis在澳大利亚传播并导致这种病原体在澳大利亚形成的因素。
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引用次数: 0
Epidemiological investigation of Entamoeba in wild rhesus macaques in China: A novel ribosomal lineage and genetic differentiation of Entamoeba nuttalli 中国野生猕猴中恩塔米巴虫的流行病学调查:一种新的核糖体系和果塔利恩塔米巴虫的遗传分化
IF 4 2区 医学 Q1 PARASITOLOGY Pub Date : 2024-04-10 DOI: 10.1016/j.ijpara.2024.04.002
Mengshi Yu , Yongfang Yao , Xin Li , Aoxing Su , Meng Xie , Ying Xiong , Shengzhi Yang , Qingyong Ni , Hongtao Xiao , Huailiang Xu

Wild rhesus macaques are a potential source of zoonotic parasites for humans, and Entamoeba spp. are common intestinal parasites. To investigate the prevalence of Entamoeba 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 Entamoeba 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 Entamoeba 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 (P < 0.001). Three zoonotic species were identified: Entamoeba chattoni (60.9%) was the most prevalent species and distributed in all the populations, followed by Entamoeba coli (33.3%) and Entamoeba nuttalli (17.4%). In addition, a novel Entamoeba ribosomal lineage named RL13 (22.8%) was identified, and phylogenetic analysis revealed a close genetic relationship between RL13 and Entamoeba. hartmanni. Genotyping of E. nuttalli obtained 24 genotypes from five populations and further analysis showed E. nuttalli had a high degree of genetic differentiation (FST > 0.25, Nm < 1) between the host populations. The result of analysis of molecular variance (AMOVA) revealed that observed genetic differences mainly originate from differences among populations (FST = 0.91). Meanwhile, the phylogenetic tree showed that these genotypes of E. nuttalli were clustered according to geographical populations, indicating a significant phylogeographic distribution pattern. Considering the potential pathogenicity of E. nuttalli, attention should be paid to its risk of zoonotic transmission.

野生猕猴是人类人畜共患病寄生虫的潜在来源,而恩塔莫巴属是常见的肠道寄生虫。为了调查中国野生猕猴体内恩塔莫阿虫的流行情况,并探索潜在致病物种恩塔莫阿虫的基因分化,研究人员从5个高海拔种群(HAG,海拔2,800-4,100米)和4个低海拔种群(LAG,海拔5-1,000米)采集了共276份粪便样本。采用基于 ssrRNA 基因的 PCR 方法检测感染情况。根据六个与 tRNA 相连的短串联重复(STR)位点对 E. nuttalli 进行基因分型,以进一步进行遗传分析。结果显示,中国野生猕猴的感染率(69.2%)很高,尤其是在宿主种群间,LAG的感染率明显高于HAG(0.25,Nm < 1)。分子方差分析(AMOVA)结果显示,所观察到的遗传差异主要来源于种群间的差异(F = 0.91)。同时,系统发生树显示,这些基因型按地理种群聚类,表明存在显著的系统地理分布模式。考虑到该病毒的潜在致病性,应关注其在人畜间传播的风险。
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引用次数: 0
Effects of regional coordination of salmon louse control in reducing negative impacts of salmonid aquaculture on wild salmonids 鲑虱控制区域协调在减少鲑鱼养殖对野生鲑鱼负面影响方面的作用。
IF 4 2区 医学 Q1 PARASITOLOGY Pub Date : 2024-04-10 DOI: 10.1016/j.ijpara.2024.04.003
Leif Christian Stige , Peder A. Jansen , Kari O. Helgesen

Parasitic salmon lice (Lepeophtheirus salmonis) 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.

寄生性鲑虱(Lepeophtheirus salmonis)是露天网箱中鲑科鱼类可持续生长的一个制约因素,近年来,这一问题已导致挪威水产养殖最密集地区的产量趋于平稳。通过所谓的 "红绿灯 "系统,在区域范围内对允许的最大生物量进行监管,根据设定的目标对洄游野生鲑鱼蜕皮后因鲑虱引起的死亡率进行评估。作为一项案例研究,我们调查了一个特定的水产养殖密集区如何充分降低虱子水平,以实现对野生鲑鱼的低影响。虚拟蜕皮后模型使用鱼类养殖场报告的鲑虱数量数据作为关键输入数据,并估算蜕皮后野生外迁大西洋鲑鱼因鲑虱引起的死亡率,对该模型输出结果的分析表明,当地养殖场的雌虱数量必须在春季减少一半,才能达到交通灯系统所暗示的目标。模拟拟议的协调生产和休耕新计划的建模结果证明是有益的,总体上减少了虱子侵扰和治疗工作。然而,在这种情况下,春季虱子数量的年际变异性增加,这意味着当许多农场进入第二个生产年时,虱子数量高得令人无法接受。然后,我们将协调生产与其他虱子控制措施相结合。只有降低研究区域开放式网箱养殖鲑鱼密度的措施才能将鲑鱼虱害降低到可接受的水平。这可以通过放养较大的鱼类以减少暴露时间,或通过减少鱼类数量(如在封闭单元中生产)来实现。
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引用次数: 0
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 寻找寄生虫生态学中的共同模式:物种和宿主对南非有蹄类动物蠕虫和南美啮齿动物跳蚤β多样性的贡献
IF 4 2区 医学 Q1 PARASITOLOGY Pub Date : 2024-04-10 DOI: 10.1016/j.ijpara.2024.04.001
Ivan G. Horak , Joop Boomker , Vasily I. Grabovsky , Irina S. Khokhlova , Kerstin Junker , Juliana P. Sanchez , M. Fernanda López Berrizbeitia , Boris R. Krasnov

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.

我们通过调查南非三种有蹄类动物的蠕虫和南美洲 11 种啮齿类动物的跳蚤中的寄生虫物种和宿主对次级群落(=宿主个体寄生的寄生虫集合体)β-多样性的贡献,寻找寄生虫生态学中的共同模式,假定对截然不同的寄生虫和宿主的模式进行比较将使我们能够判断这些模式的普遍性或至少是共同性。我们使用了关于寄生虫物种组成和数量的数据,并询问:(i) 寄生虫物种的属性(蠕虫的生命周期、传播方式和宿主特异性;跳蚤的硬质栉、微生境偏好和宿主特异性)或其种群结构(平均丰度和/或流行率)以及 (ii) 宿主特征(性别和年龄)是否会影响寄生虫和宿主物种对寄生虫贝塔多样性(SCBD 和 HCBD)的贡献。我们发现,寄生虫物种的形态和生态属性大多与其 SCBD 无关。相反,有蹄类和啮齿类动物的寄生虫 SCBD 会随着寄生虫平均丰度或流行率或两者的增加而显著增加。宿主特征对寄生虫繁殖力的影响仅在少数宿主身上有所体现。总的来说,寄生虫次群落的贝塔多样性似乎是由寄生虫种类的变化而非单个宿主所寄生的寄生虫群落的独特性所驱动的。我们的结论是,某些生态模式(如SCBD与寄生虫丰度/流行率之间的关系)似乎是共同的,在不同地理区域的不同宿主-寄生虫关联之间没有差异,而其他模式(SCBD与寄生虫物种属性之间的关系)则是偶然的,取决于寄生虫和宿主的特性。
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引用次数: 0
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International journal for parasitology
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