Pub Date : 2024-11-20DOI: 10.1186/s13071-024-06517-w
José de la Fuente, Isidro Sobrino, Margarita Villar
East Coast fever is a tick-borne theileriosis caused by Theileria parva, a protozoan parasite with the primary vector being the tick Rhipicephalus appendiculatus. This disease poses significant challenges in sub-Saharan Africa, leading to severe economic losses by causing the death of over one million livestock annually. Current control measures include vector control with acaricides and the "infection and treatment" method, which involves immunization with live sporozoites of the pathogen and treatment with long acting oxytetracycline. Despite their effectiveness, these methods face scalability and usability issues, necessitating the development of new prevention strategies, particularly in the field of vaccines for the effective and sustainable control of East Coast fever. In this primer focus, East Coast fever serves as a case study to highlight recent concepts and advancements in tick and tick-borne disease vaccine research. Vaccine design and evaluation processes are reviewed, encompassing the utilization of omics datasets and knowledge on vectors and pathogens, and exploring new design methods, such as quantum vaccinomics and messenger RNA (mRNA)-based vaccines. Key limitations and areas requiring further research are addressed, including insufficient understanding of host-pathogen molecular interactions, the impact of post-translational modifications, and vaccine efficacy variability across different trials. Additionally, new research objectives are proposed to address East Coast fever but with possible impact on other tick-borne diseases. It includes advancing knowledge on tick-pathogen-host molecular interactions, studying tick microbiota, developing novel design approaches, such as combining tick and pathogen epitopes in chimeric vaccines (exemplified by the q38-p67c case), and exploring new immunological enhancers and delivery platforms.
{"title":"Design and evaluation of vaccines for the control of the etiological agent of East Coast fever.","authors":"José de la Fuente, Isidro Sobrino, Margarita Villar","doi":"10.1186/s13071-024-06517-w","DOIUrl":"https://doi.org/10.1186/s13071-024-06517-w","url":null,"abstract":"<p><p>East Coast fever is a tick-borne theileriosis caused by Theileria parva, a protozoan parasite with the primary vector being the tick Rhipicephalus appendiculatus. This disease poses significant challenges in sub-Saharan Africa, leading to severe economic losses by causing the death of over one million livestock annually. Current control measures include vector control with acaricides and the \"infection and treatment\" method, which involves immunization with live sporozoites of the pathogen and treatment with long acting oxytetracycline. Despite their effectiveness, these methods face scalability and usability issues, necessitating the development of new prevention strategies, particularly in the field of vaccines for the effective and sustainable control of East Coast fever. In this primer focus, East Coast fever serves as a case study to highlight recent concepts and advancements in tick and tick-borne disease vaccine research. Vaccine design and evaluation processes are reviewed, encompassing the utilization of omics datasets and knowledge on vectors and pathogens, and exploring new design methods, such as quantum vaccinomics and messenger RNA (mRNA)-based vaccines. Key limitations and areas requiring further research are addressed, including insufficient understanding of host-pathogen molecular interactions, the impact of post-translational modifications, and vaccine efficacy variability across different trials. Additionally, new research objectives are proposed to address East Coast fever but with possible impact on other tick-borne diseases. It includes advancing knowledge on tick-pathogen-host molecular interactions, studying tick microbiota, developing novel design approaches, such as combining tick and pathogen epitopes in chimeric vaccines (exemplified by the q38-p67c case), and exploring new immunological enhancers and delivery platforms.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"479"},"PeriodicalIF":3.0,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142681591","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 : 2024-11-20DOI: 10.1186/s13071-024-06561-6
Frans Jongejan, Laura Berger, Laura Homminga, Iris Hulsebos, Alita Petersen, Priscila Teixeira Ferreira, José Reck, Guilherme Klafke
Background: One bioassay for detecting acaricide resistance in livestock ticks is the adult immersion test (AIT), wherein engorged ticks are briefly immersed into a solution of a particular acaricidal compound and examined for mortality, their egg-laying capacity and offspring hatchability in vitro. Usually, the recommended label dose or an established discriminating dose of an acaricide is used to determine high mortality (≥ 95%) of susceptible tick strains. Such a test intends to detect the presence of resistance in a tick population. However, the adult immersion test does not directly translate the bioassay results to the predicted efficacy in the field. In this paper, we used the AIT as an initial screening bioassay supplemented with the resistance intensity test (RIT), a novel larval-based bioassay, wherein the resistance level can be determined and translated to the expected field efficacy. This was done by adopting World Health Organisation (WHO) guidelines for resistance detection in mosquitoes, which combines a 1 × recommended dose with 5 × and 10 × concentrated doses to reveal low, moderate and high resistance intensity, respectively.
Methods: Engorged Rhipicephalus microplus ticks were collected from cattle at six different ranches across Rio Grande do Sul, Brazil, as part of the state's acaricide resistance surveillance program. Groups of adult ticks from each field collection were subjected to the AIT from each field sample. Additionally, engorged female ticks from each ranch were allowed to lay eggs, and their larval progeny aged 14 to 28 days were then used in the RIT. Deltamethrin and a combination of cypermethrin, chlorpyrifos and piperonyl butoxide were used in both tests, and the results were statistically analysed.
Results: The in vitro efficacy of deltamethrin against adult ticks in the AIT ranged between 8.74% and 25.38%. The corresponding RIT results on their larval progeny indicated a high resistance level. In the immersion test, the in vitro efficacy of the combination of cypermethrin, chlorpyrifos, and piperonyl butoxide against adult ticks ranged between 49.31% and 100%. The corresponding RIT results on their larval progeny indicated a similar response ranging from fully susceptible to low or moderate resistance. The Pearson correlation coefficient (r = 0.883) showed a high correlation between tick mortality at the 1 × recommended concentrations of acaricides in both tests.
Conclusions: The resistance intensity test is a valuable addition to the range of bioassays currently available for detecting acaricide resistance by determining the level of acaricide resistance. This is relevant to whether or not to continue using a particular acaricidal class for controlling cattle ticks.
背景:检测家畜蜱对杀螨剂抗药性的一种生物测定方法是成蜱浸泡试验(AIT),将充血的蜱短暂浸入特定杀螨化合物溶液中,在体外检测其死亡率、产卵能力和后代孵化率。通常,使用杀螨剂的推荐标签剂量或既定鉴别剂量来确定易感蜱株的高死亡率(≥ 95%)。这种试验旨在检测蜱群中是否存在抗药性。然而,成虫浸泡试验并不能直接将生物测定结果转化为预测的田间药效。在本文中,我们使用成虫浸泡试验作为初步筛选生物测定,并辅以抗药性强度试验(RIT),这是一种基于幼虫的新型生物测定,可确定抗药性水平并将其转化为预期的田间药效。为此,采用了世界卫生组织(WHO)的蚊虫抗药性检测准则,将 1 倍推荐剂量与 5 倍和 10 倍浓缩剂量相结合,分别显示低、中和高抗药性强度:方法:作为巴西南里奥格兰德州杀螨剂抗药性监测计划的一部分,从该州六个不同牧场的牛身上采集了啮齿类 Rhipicephalus microplus蜱。从每个牧场采集的成蜱组都接受了来自每个牧场样本的 AIT 检测。此外,还让每个牧场的充血雌蜱产卵,然后将其 14 至 28 天的幼虫后代用于 RIT。两项试验均使用了溴氰菊酯以及氯氰菊酯、毒死蜱和胡椒基丁醚的组合,并对结果进行了统计分析:在 AIT 中,溴氰菊酯对成蜱的体外效力在 8.74% 和 25.38% 之间。对其幼虫后代的相应 RIT 结果表明抗药性水平很高。在浸泡试验中,氯氰菊酯、毒死蜱和胡椒基丁醚对成蜱的体外药效在 49.31% 和 100% 之间。对其幼虫后代的相应 RIT 结果也显示出类似的反应,从完全易感到低度或中度抗性。皮尔逊相关系数(r = 0.883)显示,在这两项试验中,1 × 建议浓度杀螨剂的蜱死亡率之间存在高度相关性:通过确定杀螨剂的抗药性水平,抗药性强度试验是对目前可用来检测杀螨剂抗药性的一系列生物测定方法的重要补充。这关系到是否继续使用某种杀螨剂来控制牛蜱。
{"title":"Resistance intensity test (RIT): a novel bioassay for quantifying the level of acaricide resistance in Rhipicephalus microplus ticks.","authors":"Frans Jongejan, Laura Berger, Laura Homminga, Iris Hulsebos, Alita Petersen, Priscila Teixeira Ferreira, José Reck, Guilherme Klafke","doi":"10.1186/s13071-024-06561-6","DOIUrl":"https://doi.org/10.1186/s13071-024-06561-6","url":null,"abstract":"<p><strong>Background: </strong>One bioassay for detecting acaricide resistance in livestock ticks is the adult immersion test (AIT), wherein engorged ticks are briefly immersed into a solution of a particular acaricidal compound and examined for mortality, their egg-laying capacity and offspring hatchability in vitro. Usually, the recommended label dose or an established discriminating dose of an acaricide is used to determine high mortality (≥ 95%) of susceptible tick strains. Such a test intends to detect the presence of resistance in a tick population. However, the adult immersion test does not directly translate the bioassay results to the predicted efficacy in the field. In this paper, we used the AIT as an initial screening bioassay supplemented with the resistance intensity test (RIT), a novel larval-based bioassay, wherein the resistance level can be determined and translated to the expected field efficacy. This was done by adopting World Health Organisation (WHO) guidelines for resistance detection in mosquitoes, which combines a 1 × recommended dose with 5 × and 10 × concentrated doses to reveal low, moderate and high resistance intensity, respectively.</p><p><strong>Methods: </strong>Engorged Rhipicephalus microplus ticks were collected from cattle at six different ranches across Rio Grande do Sul, Brazil, as part of the state's acaricide resistance surveillance program. Groups of adult ticks from each field collection were subjected to the AIT from each field sample. Additionally, engorged female ticks from each ranch were allowed to lay eggs, and their larval progeny aged 14 to 28 days were then used in the RIT. Deltamethrin and a combination of cypermethrin, chlorpyrifos and piperonyl butoxide were used in both tests, and the results were statistically analysed.</p><p><strong>Results: </strong>The in vitro efficacy of deltamethrin against adult ticks in the AIT ranged between 8.74% and 25.38%. The corresponding RIT results on their larval progeny indicated a high resistance level. In the immersion test, the in vitro efficacy of the combination of cypermethrin, chlorpyrifos, and piperonyl butoxide against adult ticks ranged between 49.31% and 100%. The corresponding RIT results on their larval progeny indicated a similar response ranging from fully susceptible to low or moderate resistance. The Pearson correlation coefficient (r = 0.883) showed a high correlation between tick mortality at the 1 × recommended concentrations of acaricides in both tests.</p><p><strong>Conclusions: </strong>The resistance intensity test is a valuable addition to the range of bioassays currently available for detecting acaricide resistance by determining the level of acaricide resistance. This is relevant to whether or not to continue using a particular acaricidal class for controlling cattle ticks.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"480"},"PeriodicalIF":3.0,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142681607","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 : 2024-11-20DOI: 10.1186/s13071-024-06533-w
Emmanuel Chinweuba Ottih, Frederic Tripet
Background: Eggs of anopheline mosquitoes hatch within a few days of laying and require high levels of humidity to survive. Assessing natural variation in egg hatching and its environmental and genetic determinants in sibling species of the malaria vector Anopheles gambiae s.l. is important for understanding their adaptation to variable aquatic habitats. Crucially, it can also inform insectary rearing practices toward the optimization of mosquito production for genetic vector control strategies.
Methods: Hatching rates and timing of egg hatching in long-established and recently colonized strains of An. gambiae s.s, Anopheles arabiensis, and Anopheles coluzzii, were compared under still water conditions (26 ℃) and with cold (4 ℃) and (15 ℃) water agitation regimes. Next, early and late hatching strains of the recently colonized An. coluzzii VK colony were generated through bidirectional selection for 18-23 generations to detect a genetic component for this trait.
Results: Hatching rates differed significantly between species and treatments. The older An. arabiensis Senn and An. gambiae s.s. Kisumu strains had the highest proportion of hatching and preferred the nonagitation treatment at 26 °C. In contrast, the more recently colonized An. coluzzii VK and An. arabiensis Rufisque strains had lower overall hatching success but responded strongly to agitation at 4 °C, while the An. coluzzii Mopti strain did not significantly respond to water agitation. In all strains, eggs hatching started at day 2 and continued till day 5 in the older strains, whilst it was more staggered and extended up to day 6 in the younger strains. Bidirectional selection for early and late hatching over many generations resulted in early hatching selected strains with eggs hatching 2-3 days earlier than in late hatching ones indicating a significant heritable component for these traits.
Conclusions: Water agitation and temperature and age of colonization are likely important determinants of egg hatching in natural An. gambiae s.l.
Populations: Current rearing protocols systematically select for fast hatching and result in the progressive loss of staggered egg hatching in older laboratory strains. The selection of novel slow-hatching strains may prove instrumental to enable the mass production, shipping, and release of Anopheles mosquitoes across Africa as part of genetic vector control programs.
{"title":"Natural variation in timing of egg hatching, response to water agitation, and bidirectional selection of early and late hatching strains of the malaria mosquito Anopheles gambiae sensu lato.","authors":"Emmanuel Chinweuba Ottih, Frederic Tripet","doi":"10.1186/s13071-024-06533-w","DOIUrl":"https://doi.org/10.1186/s13071-024-06533-w","url":null,"abstract":"<p><strong>Background: </strong>Eggs of anopheline mosquitoes hatch within a few days of laying and require high levels of humidity to survive. Assessing natural variation in egg hatching and its environmental and genetic determinants in sibling species of the malaria vector Anopheles gambiae s.l. is important for understanding their adaptation to variable aquatic habitats. Crucially, it can also inform insectary rearing practices toward the optimization of mosquito production for genetic vector control strategies.</p><p><strong>Methods: </strong>Hatching rates and timing of egg hatching in long-established and recently colonized strains of An. gambiae s.s, Anopheles arabiensis, and Anopheles coluzzii, were compared under still water conditions (26 ℃) and with cold (4 ℃) and (15 ℃) water agitation regimes. Next, early and late hatching strains of the recently colonized An. coluzzii VK colony were generated through bidirectional selection for 18-23 generations to detect a genetic component for this trait.</p><p><strong>Results: </strong>Hatching rates differed significantly between species and treatments. The older An. arabiensis Senn and An. gambiae s.s. Kisumu strains had the highest proportion of hatching and preferred the nonagitation treatment at 26 °C. In contrast, the more recently colonized An. coluzzii VK and An. arabiensis Rufisque strains had lower overall hatching success but responded strongly to agitation at 4 °C, while the An. coluzzii Mopti strain did not significantly respond to water agitation. In all strains, eggs hatching started at day 2 and continued till day 5 in the older strains, whilst it was more staggered and extended up to day 6 in the younger strains. Bidirectional selection for early and late hatching over many generations resulted in early hatching selected strains with eggs hatching 2-3 days earlier than in late hatching ones indicating a significant heritable component for these traits.</p><p><strong>Conclusions: </strong>Water agitation and temperature and age of colonization are likely important determinants of egg hatching in natural An. gambiae s.l.</p><p><strong>Populations: </strong>Current rearing protocols systematically select for fast hatching and result in the progressive loss of staggered egg hatching in older laboratory strains. The selection of novel slow-hatching strains may prove instrumental to enable the mass production, shipping, and release of Anopheles mosquitoes across Africa as part of genetic vector control programs.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"478"},"PeriodicalIF":3.0,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142681602","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 : 2024-11-19DOI: 10.1186/s13071-024-06567-0
Waraporn Jumpato, Wannachai Wannasingha, Chavanut Jaroenchaiwattanachote, Ronnalit Mintara, Komgrit Wongpakam, Peter H Adler, Pairot Pramual
<p><strong>Background: </strong>Leucocytozoonosis, a parasitic disease of birds, is caused by haemosporidian protozoan parasites of the genus Leucocytozoon, which infect diverse avian species, including poultry. These parasites are transmitted by several black fly species, but knowledge of the factors determining the diversity and prevalence in these vectors, which is crucial for fully understanding disease epidemiology, is largely unexplored. In this study, we investigated factors associated with the prevalence and diversity of Leucocytozoon species in black flies from Thailand.</p><p><strong>Methods: </strong>Adults of two black fly taxa (Simulium asakoae Takaoka and Davies complex and S. khelangense Takaoka, Srisuka and Saeung) were collected using sweep nets at nine locations in northern and northeastern regions of Thailand. Specimens were identified morphologically and the results corroborated by DNA barcoding. Molecular methods using specific primers for amplification of the mitochondrial cytochrome b (cyt b) gene of Leucocytozoon were used to detect the parasite in black flies. Species and lineages of Leucocytozoon were determined using the MalAvi database of malaria parasites and related haemosporidians in avian hosts. Regression analysis was used to examine relationships between Leucocytozoon diversity and prevalence, black fly abundance and habitat characteristics.</p><p><strong>Results: </strong>A total of 11,718 adult black flies were collected, of which 4367 were members of the S. asakoae complex and 7351 were S. khelangense. For molecular detection of Leucocytozoon, we randomly selected 300 individual female black flies of the S. asakoae complex and 850 females of S. khelangense pooled into groups of five individuals (= 170 pools). A total of 34 of the 300 specimens of the S. asakoae complex and 118 of the 170 pools of S. khelangense were positive for Leucocytozoon. Fifty-four lineages (haplotypes) were identified, all of which belonged to those reported in domestic chickens, Gallus gallus, with one exception that was identified in S. khelangense and found to be closely related to the Leucocytozoon lineages reported in owls; this is the first record of the latter lineage in Asian black flies. Among these haplotypes, nine and 45 were exclusively found in the S. asakoae complex and S. khelangense, respectively. No lineage was shared between these black fly taxa. Analysis of similarity (ANOSIM) revealed significant Leucocytozoon lineage composition between the two black flies. Phylogenetic analysis found that Leucocytozoon lineages in the S. asakoae complex and S. khelangense are largely isolated, agreeing with the ANOSIM result. The overall prevalence of Leucocytozoon in the S. asakoae complex was 11.3% and ranged from 9% to 13% in each collection. Leucocytozoon prevalence in S. khelangense was 21%, varying from 13% to 37% in each collection. The Shannon H' index indicated greater Leucocytozoon diversity in S. khelangense (H' = 3.044)
背景:白细胞虫病是一种鸟类寄生虫病,由白细胞虫属血孢子原生动物寄生虫引起,感染包括家禽在内的多种禽类。这些寄生虫由几种黑蝇传播,但决定这些病媒多样性和流行率的因素对充分了解疾病流行病学至关重要,但这方面的知识在很大程度上尚未得到探索。在这项研究中,我们调查了与泰国黑蝇中白细胞虫种类的流行和多样性有关的因素:方法:在泰国北部和东北部地区的 9 个地点使用扫网收集了两个黑蝇类群(Simulium asakoae Takaoka and Davies complex 和 S. khelangense Takaoka, Srisuka and Saeung)的成虫。对标本进行了形态鉴定,并通过 DNA 条形码对鉴定结果进行了确认。使用特异引物扩增线粒体细胞色素 b(cyt b)基因的分子方法检测了黑蝇中的寄生虫。利用 MalAvi 数据库确定了禽类宿主中的疟原虫和相关血孢子虫的种类和血系。采用回归分析法研究了Leucocytozoon多样性和流行率、黑蝇丰度和栖息地特征之间的关系:结果:共收集到 11718 只成年黑蝇,其中 4367 只为 S. asakoae 复合体成员,7351 只为 S. khelangense。为了进行白细胞介素的分子检测,我们随机选取了300只浅胁黑蝇复合体的雌性黑蝇和850只谢朗氏黑蝇的雌性黑蝇,每5只为一组(=170组)。在 300 个 S. asakoae 复合体标本和 170 个 S. khelangense 池中,共有 34 个标本和 118 个池子的白细胞介素阳性。鉴定出 54 个品系(单倍型),所有这些品系都属于在家鸡(Gallus gallus)中报告的品系,只有一个品系在 S. khelangense 中被鉴定出,并被发现与在猫头鹰中报告的 Leucocytozoon 品系密切相关;这是亚洲黑蝇中后一个品系的首次记录。在这些单倍型中,分别有 9 个和 45 个单倍型仅见于 S. asakoae 复合物和 S. khelangense。这些黑蝇类群之间没有共享的单系。相似性分析(ANOSIM)显示,这两种黑蝇之间有明显的亮孢子虫世系组成。系统进化分析发现,S. asakoae 复合体和 S. khelangense 中的 Leucocytozoon 系在很大程度上是孤立的,这与 ANOSIM 的结果一致。在 S. asakoae 复合菌群中,Leucocytozoon 的总体流行率为 11.3%,在每个菌群中的流行率从 9% 到 13% 不等。在 S. khelangense 中,白色念珠菌的流行率为 21%,每个采集物中的流行率从 13% 到 37% 不等。香农 H'指数表明,S. khelangense(H' = 3.044)中的白细胞虫多样性高于 S. asakoae 复合体(H' = 1.920)。回归分析表明,Leucocytozoon 多样性与黑蝇数量呈正相关,与最高气温呈负相关:本研究结果表明,泰国的 S. asakoae 复合体和 S. khelangense 中的 Leucocytozoon 系的流行率和多样性与这些黑蝇的数量和气温有关。鉴定出的亮孢子虫系还显示出一定程度的黑蝇类群特异性,这可能与这些媒介的不同丰度峰值有关。有利于黑蝇发展的环境条件可能是白细胞虫流行、多样性和病媒-寄生虫共同进化的驱动因素。
{"title":"Diversity and prevalence of Leucocytozoon in black flies (Diptera: Simuliidae) of Thailand.","authors":"Waraporn Jumpato, Wannachai Wannasingha, Chavanut Jaroenchaiwattanachote, Ronnalit Mintara, Komgrit Wongpakam, Peter H Adler, Pairot Pramual","doi":"10.1186/s13071-024-06567-0","DOIUrl":"https://doi.org/10.1186/s13071-024-06567-0","url":null,"abstract":"<p><strong>Background: </strong>Leucocytozoonosis, a parasitic disease of birds, is caused by haemosporidian protozoan parasites of the genus Leucocytozoon, which infect diverse avian species, including poultry. These parasites are transmitted by several black fly species, but knowledge of the factors determining the diversity and prevalence in these vectors, which is crucial for fully understanding disease epidemiology, is largely unexplored. In this study, we investigated factors associated with the prevalence and diversity of Leucocytozoon species in black flies from Thailand.</p><p><strong>Methods: </strong>Adults of two black fly taxa (Simulium asakoae Takaoka and Davies complex and S. khelangense Takaoka, Srisuka and Saeung) were collected using sweep nets at nine locations in northern and northeastern regions of Thailand. Specimens were identified morphologically and the results corroborated by DNA barcoding. Molecular methods using specific primers for amplification of the mitochondrial cytochrome b (cyt b) gene of Leucocytozoon were used to detect the parasite in black flies. Species and lineages of Leucocytozoon were determined using the MalAvi database of malaria parasites and related haemosporidians in avian hosts. Regression analysis was used to examine relationships between Leucocytozoon diversity and prevalence, black fly abundance and habitat characteristics.</p><p><strong>Results: </strong>A total of 11,718 adult black flies were collected, of which 4367 were members of the S. asakoae complex and 7351 were S. khelangense. For molecular detection of Leucocytozoon, we randomly selected 300 individual female black flies of the S. asakoae complex and 850 females of S. khelangense pooled into groups of five individuals (= 170 pools). A total of 34 of the 300 specimens of the S. asakoae complex and 118 of the 170 pools of S. khelangense were positive for Leucocytozoon. Fifty-four lineages (haplotypes) were identified, all of which belonged to those reported in domestic chickens, Gallus gallus, with one exception that was identified in S. khelangense and found to be closely related to the Leucocytozoon lineages reported in owls; this is the first record of the latter lineage in Asian black flies. Among these haplotypes, nine and 45 were exclusively found in the S. asakoae complex and S. khelangense, respectively. No lineage was shared between these black fly taxa. Analysis of similarity (ANOSIM) revealed significant Leucocytozoon lineage composition between the two black flies. Phylogenetic analysis found that Leucocytozoon lineages in the S. asakoae complex and S. khelangense are largely isolated, agreeing with the ANOSIM result. The overall prevalence of Leucocytozoon in the S. asakoae complex was 11.3% and ranged from 9% to 13% in each collection. Leucocytozoon prevalence in S. khelangense was 21%, varying from 13% to 37% in each collection. The Shannon H' index indicated greater Leucocytozoon diversity in S. khelangense (H' = 3.044)","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"475"},"PeriodicalIF":3.0,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142676423","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 : 2024-11-19DOI: 10.1186/s13071-024-06505-0
Almiro Pires da Silva Neto, Juliana Vitoriano-Souza, Mariana Ivo Khouri, Regiane Degan Favaro, Robert Alan Wilson, Luciana Cezar de Cerqueira Leite, Pablo Ivan Pereira Ramos, Leonardo Paiva Farias
Background: Despite decades of research, an effective schistosomiasis vaccine remains elusive. The radiation-attenuated (RA) cercarial vaccine remains the best model for eliciting high levels of protection. We have recently explored this model in mice to identify potentially protective pathways by examining gene expression patterns in peripheral blood mononuclear cells (PBMC).
Methods: Herein, we reanalyzed the transcriptomic data from PBMC obtained from vaccinated and infected C57BL/6 mice in three timepoints (Days 7 and 17 after infection or vaccination and Day 7 post-challenge). In addition, we generated new data on PBMC collected 35 days after infection. Deconvolution analysis was performed to estimate immune cell composition by CIBERSORTx. Gene co-expression networks and over-representation analysis (ORA) were performed using the CEMiTool package. Protein-protein interaction networks were constructed using STRING, and the hub proteins for each module were identified using Cytoscape.
Results: Co-expression network analysis identified a module (M2) associated with the infection process, grouping genes related to a Th2 immune response, and a second module (M6) associated with the vaccination process, displaying pathways related to a Th1 response, CD8 + T cells and NK cells. Within each module, five hub proteins were identified based on protein-protein interaction networks. The M2 infection module revealed Chil3, Il4, Cx3cr1, Emr1 and Ccl2 as hubs, while module M6, associated with vaccination, disclosed Prf1, Klrc1, IFN-γ, Ncr1 and Tbx21 as hub proteins.
Conclusions: Our data point to the potentiald role of NK cells that may contribute to the RA vaccine response through the production of IFN-γ orchestrated by the T-bet transcription factor (Tbx21).
{"title":"Co-expression gene module analysis in response to attenuated cercaria vaccine reveals a critical role for NK cells in protection against Schistosoma mansoni.","authors":"Almiro Pires da Silva Neto, Juliana Vitoriano-Souza, Mariana Ivo Khouri, Regiane Degan Favaro, Robert Alan Wilson, Luciana Cezar de Cerqueira Leite, Pablo Ivan Pereira Ramos, Leonardo Paiva Farias","doi":"10.1186/s13071-024-06505-0","DOIUrl":"https://doi.org/10.1186/s13071-024-06505-0","url":null,"abstract":"<p><strong>Background: </strong>Despite decades of research, an effective schistosomiasis vaccine remains elusive. The radiation-attenuated (RA) cercarial vaccine remains the best model for eliciting high levels of protection. We have recently explored this model in mice to identify potentially protective pathways by examining gene expression patterns in peripheral blood mononuclear cells (PBMC).</p><p><strong>Methods: </strong>Herein, we reanalyzed the transcriptomic data from PBMC obtained from vaccinated and infected C57BL/6 mice in three timepoints (Days 7 and 17 after infection or vaccination and Day 7 post-challenge). In addition, we generated new data on PBMC collected 35 days after infection. Deconvolution analysis was performed to estimate immune cell composition by CIBERSORTx. Gene co-expression networks and over-representation analysis (ORA) were performed using the CEMiTool package. Protein-protein interaction networks were constructed using STRING, and the hub proteins for each module were identified using Cytoscape.</p><p><strong>Results: </strong>Co-expression network analysis identified a module (M2) associated with the infection process, grouping genes related to a Th2 immune response, and a second module (M6) associated with the vaccination process, displaying pathways related to a Th1 response, CD8 + T cells and NK cells. Within each module, five hub proteins were identified based on protein-protein interaction networks. The M2 infection module revealed Chil3, Il4, Cx3cr1, Emr1 and Ccl2 as hubs, while module M6, associated with vaccination, disclosed Prf1, Klrc1, IFN-γ, Ncr1 and Tbx21 as hub proteins.</p><p><strong>Conclusions: </strong>Our data point to the potentiald role of NK cells that may contribute to the RA vaccine response through the production of IFN-γ orchestrated by the T-bet transcription factor (Tbx21).</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"476"},"PeriodicalIF":3.0,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142676420","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 : 2024-11-18DOI: 10.1186/s13071-024-06562-5
Isabella Fernandes Martins Santos, Douglas de Souza Moreira, Karla Ferreira Costa, Juliana Martins Ribeiro, Silvane Maria Fonseca Murta, Ana Maria Murta Santi
Background: Ascorbate peroxidase (APX) has emerged as a promising target for chemotherapy because of its absence in humans and crucial role in the antioxidant defence of trypanosomatids. APXs, which are class I haeme-containing enzymes, reduces hydrogen peroxide using ascorbate to produce water and monodehydroascorbate, thereby preventing cell damage caused by H2O2.
Methods: We aimed to create an APX-knockout L. infantum line using CRISPR/Cas9. Despite unsuccessful attempts at full knockouts, we achieved deletion of chromosomal copies post-APX episomal insertion, yielding LiΔchrAPX::LbAPX parasites. We performed phenotypic characterization to assess the impact of these genetic modifications, which included the determination of APX transcript expression levels using quantitative PCR, drug sensitivity, infectivity, and parasite survival in macrophages.
Results: Quantitative polymerase chain reaction (PCR) analysis revealed a 10- to 13-fold reduction in APX transcript expression in LiΔchrAPX::LbAPX compared with wild-type (LiWT) and APX-overexpressing (Li::Cas9::LbAPX) parasites, respectively. The episomes in those knockdown parasites remained stable even after 20 drug-free passages in vitro. Li::Cas9::LbAPX parasites showed increased resistance to trivalent antimony (SbIII) and isoniazid, reduced tolerance to H2O2, and unchanged macrophage infectivity compared with LiWT. In contrast, LiΔchrAPX::LbAPX parasites were more sensitive to SbIII and isoniazid, exhibited greater susceptibility to H2O2-induced oxidative stress, and 72 h post-infection, showed fewer infected macrophages and intracellular amastigotes compared with LiWT parasites.
Conclusions: Our findings hint at the indispensability of APX in L. infantum and raise the possibility of its potential as a therapeutic target for leishmaniasis.
{"title":"Ascorbate peroxidase modulation confirms key role in Leishmania infantum oxidative defence.","authors":"Isabella Fernandes Martins Santos, Douglas de Souza Moreira, Karla Ferreira Costa, Juliana Martins Ribeiro, Silvane Maria Fonseca Murta, Ana Maria Murta Santi","doi":"10.1186/s13071-024-06562-5","DOIUrl":"10.1186/s13071-024-06562-5","url":null,"abstract":"<p><strong>Background: </strong>Ascorbate peroxidase (APX) has emerged as a promising target for chemotherapy because of its absence in humans and crucial role in the antioxidant defence of trypanosomatids. APXs, which are class I haeme-containing enzymes, reduces hydrogen peroxide using ascorbate to produce water and monodehydroascorbate, thereby preventing cell damage caused by H<sub>2</sub>O<sub>2</sub>.</p><p><strong>Methods: </strong>We aimed to create an APX-knockout L. infantum line using CRISPR/Cas9. Despite unsuccessful attempts at full knockouts, we achieved deletion of chromosomal copies post-APX episomal insertion, yielding LiΔchrAPX::LbAPX parasites. We performed phenotypic characterization to assess the impact of these genetic modifications, which included the determination of APX transcript expression levels using quantitative PCR, drug sensitivity, infectivity, and parasite survival in macrophages.</p><p><strong>Results: </strong>Quantitative polymerase chain reaction (PCR) analysis revealed a 10- to 13-fold reduction in APX transcript expression in LiΔchrAPX::LbAPX compared with wild-type (LiWT) and APX-overexpressing (Li::Cas9::LbAPX) parasites, respectively. The episomes in those knockdown parasites remained stable even after 20 drug-free passages in vitro. Li::Cas9::LbAPX parasites showed increased resistance to trivalent antimony (Sb<sup>III</sup>) and isoniazid, reduced tolerance to H<sub>2</sub>O<sub>2</sub>, and unchanged macrophage infectivity compared with LiWT. In contrast, LiΔchrAPX::LbAPX parasites were more sensitive to Sb<sup>III</sup> and isoniazid, exhibited greater susceptibility to H<sub>2</sub>O<sub>2</sub>-induced oxidative stress, and 72 h post-infection, showed fewer infected macrophages and intracellular amastigotes compared with LiWT parasites.</p><p><strong>Conclusions: </strong>Our findings hint at the indispensability of APX in L. infantum and raise the possibility of its potential as a therapeutic target for leishmaniasis.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"472"},"PeriodicalIF":3.0,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11575162/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142668599","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 : 2024-11-18DOI: 10.1186/s13071-024-06564-3
Reem M Ramadan, Alaa F Bakr, Esraa Fouad, Faten F Mohammed, Azza M Abdel-Wahab, Sahar Z Abdel-Maogood, Mohamed M El-Bahy, Mai A Salem
Background: Hemoprotozoan diseases, especially trypanosomosis and theileriosis, adversely affect the productivity, growth, and performance of camels. Regular sampling and investigation of camels are challenging due to several factors. Consequently, there is a lack of knowledge on camel parasite genotyping, cytokine production, and oxidative stress parameters during infection.
Methods: The present study investigated two critical blood protozoa infecting camels in Egypt, Trypanosoma evansi and Theileria annulata, using molecular methods, specifically 18S rRNA gene analysis. Following molecular confirmation, experimental infections were induced in Swiss albino mice to assess the expression of immune response genes and oxidative stress parameters. The study further explored the correlation between histopathological alterations and inflammatory reactions in the kidney, spleen, and liver of infected mice, alongside the immunohistochemical expression of caspase-3, proliferating cell nuclear antigen (PCNA), and tumor necrosis factor (TNF).
Results: Trypanosoma evansi and T. annulata isolated from naturally infected camels were molecularly identified and deposited in GenBank under accession numbers OR116429 and OR103130, respectively. Infection with T. evansi and T. annulata caused significant adverse effects on the immune condition of infected mice, increasing the pathogenicity of the infection. This was evidenced by a significant increase in oxidative stress parameter levels in both naturally infected camels and experimentally infected mice compared to healthy controls. Furthermore, the expression of immune response genes was significantly elevated in infected mice. Immunohistochemistry analysis showed a pronounced upregulation of caspase-3, PCNA, and TNF in the infected groups relative to the control group. These findings are the first to be reported in Egypt.
Conclusions: This study successfully identified and genotyped two economically important blood protozoa, T. evansi and T. annulata, from camels in Egypt. Additionally, the experimental animal model provided valuable insights into the immune response, oxidative stress, and histopathological changes induced by these parasites, demonstrating comparable results to naturally infected camels. These findings highlight the potential of this model to study parasite-host interactions and immune responses, contributing to a better understanding of the pathogenic mechanisms of T. evansi and T. annulata infections. This model may be useful for future studies focused on disease control and therapeutic interventions.
背景:血吸虫疾病,尤其是锥虫病和丝虫病,对骆驼的生产力、生长和性能产生了不利影响。由于多种因素,对骆驼进行定期采样和调查具有挑战性。因此,人们对骆驼寄生虫的基因分型、细胞因子的产生以及感染期间的氧化应激参数缺乏了解:本研究采用分子方法,特别是 18S rRNA 基因分析,调查了埃及骆驼感染的两种重要血液原生动物--埃文斯锥虫(Trypanosoma evansi)和年轮虫(Theileria annulata)。经分子确认后,诱导瑞士白化小鼠进行实验感染,以评估免疫反应基因的表达和氧化应激参数。该研究进一步探讨了受感染小鼠肾脏、脾脏和肝脏组织病理学改变与炎症反应之间的相关性,以及 Caspase-3、增殖细胞核抗原(PCNA)和肿瘤坏死因子(TNF)的免疫组化表达:结果:从自然感染的骆驼身上分离出的Trypanosoma evansi和T. annulata经分子鉴定后存入GenBank,登录号分别为OR116429和OR103130。T.evansi和T.annulata会对受感染小鼠的免疫状况产生显著的不利影响,增加感染的致病性。与健康对照组相比,自然感染的骆驼和实验感染的小鼠的氧化应激参数水平都显著增加,这就证明了这一点。此外,受感染小鼠的免疫反应基因表达也明显升高。免疫组化分析表明,与对照组相比,感染组的 Caspase-3、PCNA 和 TNF 明显上调。这些发现在埃及尚属首次报道:本研究成功地从埃及骆驼身上鉴定出了两种具有重要经济价值的血液原生动物--T. evansi 和 T. annulata,并对其进行了基因分型。此外,实验动物模型为了解这些寄生虫引起的免疫反应、氧化应激和组织病理学变化提供了宝贵的信息,其结果与自然感染的骆驼相当。这些发现凸显了这一模型在研究寄生虫-宿主相互作用和免疫反应方面的潜力,有助于更好地了解 T. evansi 和 T. annulata 感染的致病机制。该模型可能有助于未来以疾病控制和治疗干预为重点的研究。
{"title":"Novel insights into antioxidant status, gene expression, and immunohistochemistry in an animal model infected with camel-derived Trypanosoma evansi and Theileria annulata.","authors":"Reem M Ramadan, Alaa F Bakr, Esraa Fouad, Faten F Mohammed, Azza M Abdel-Wahab, Sahar Z Abdel-Maogood, Mohamed M El-Bahy, Mai A Salem","doi":"10.1186/s13071-024-06564-3","DOIUrl":"10.1186/s13071-024-06564-3","url":null,"abstract":"<p><strong>Background: </strong>Hemoprotozoan diseases, especially trypanosomosis and theileriosis, adversely affect the productivity, growth, and performance of camels. Regular sampling and investigation of camels are challenging due to several factors. Consequently, there is a lack of knowledge on camel parasite genotyping, cytokine production, and oxidative stress parameters during infection.</p><p><strong>Methods: </strong>The present study investigated two critical blood protozoa infecting camels in Egypt, Trypanosoma evansi and Theileria annulata, using molecular methods, specifically 18S rRNA gene analysis. Following molecular confirmation, experimental infections were induced in Swiss albino mice to assess the expression of immune response genes and oxidative stress parameters. The study further explored the correlation between histopathological alterations and inflammatory reactions in the kidney, spleen, and liver of infected mice, alongside the immunohistochemical expression of caspase-3, proliferating cell nuclear antigen (PCNA), and tumor necrosis factor (TNF).</p><p><strong>Results: </strong>Trypanosoma evansi and T. annulata isolated from naturally infected camels were molecularly identified and deposited in GenBank under accession numbers OR116429 and OR103130, respectively. Infection with T. evansi and T. annulata caused significant adverse effects on the immune condition of infected mice, increasing the pathogenicity of the infection. This was evidenced by a significant increase in oxidative stress parameter levels in both naturally infected camels and experimentally infected mice compared to healthy controls. Furthermore, the expression of immune response genes was significantly elevated in infected mice. Immunohistochemistry analysis showed a pronounced upregulation of caspase-3, PCNA, and TNF in the infected groups relative to the control group. These findings are the first to be reported in Egypt.</p><p><strong>Conclusions: </strong>This study successfully identified and genotyped two economically important blood protozoa, T. evansi and T. annulata, from camels in Egypt. Additionally, the experimental animal model provided valuable insights into the immune response, oxidative stress, and histopathological changes induced by these parasites, demonstrating comparable results to naturally infected camels. These findings highlight the potential of this model to study parasite-host interactions and immune responses, contributing to a better understanding of the pathogenic mechanisms of T. evansi and T. annulata infections. This model may be useful for future studies focused on disease control and therapeutic interventions.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"474"},"PeriodicalIF":3.0,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11575088/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142668605","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 : 2024-11-18DOI: 10.1186/s13071-024-06571-4
Katrin Bisterfeld, Marie-Kristin Raulf, Patrick Waindok, Andrea Springer, Johannes Lang, Michael Lierz, Ursula Siebert, Christina Strube
Background: For several decades, the European wildcat (Felis silvestris) has gradually been returning to the forests of Germany, mainly in the central and southwestern regions. To increase the knowledge about this threatened species, the endoparasite status of dead found specimens from Germany was surveyed.
Methods: A total of 118 wildcats were examined for endoparasites in peritoneal organs and skeletal muscles. Owing to decomposition or incomplete carcasses, 104 gastrointestinal tracts (stomachs and intestines), 101 livers with gallbladders, 99 urinary bladders, as well as kidneys of 95 and skeletal muscles of 112 specimens were available for examination. All detected parasites were identified morphologically to genus or species level, followed by molecular examinations of one to ten specimens of each parasite species.
Results: Overall endoparasite prevalence in peritoneal organs was 99.0% (103/104). Among the 99.0% (103/104) infected gastrointestinal tracts, the most frequent species were Toxocara cati (95.2% [99/104]), Hydatigera kamiyai (84.6% [88/104]), Mesocestoides litteratus (69.2% [72/104]), Strongyloides spp. (58.7% [61/104]), Cylicospirura petrowi (37.5% [39/104]), Ancylostoma tubaeforme (31.7% [33/104]), Capillaria putorii (24.0% [25/104]), and Echinococcus multilocularis (18.3% [19/104]). In 77.8% (77/99) of the urinary bladders, Capillaria plica and/or Capillaria feliscati were detected. Moreover, the liver fluke Metorchis bilis occurred in 2.0% (2/101) of the livers, and roundworm larvae (presumably Toxocara spp.) were detected in 33.0% (37/112) of the muscle samples.
Conclusions: These results show a broad spectrum of endoparasite species infecting European wildcats in Germany. It might be assumed that some of the endoparasites could pose a risk to domestic cats (Felis catus) and humans through spillover events, or may be transmitted from domestic cats to the free-ranging population, posing a potential risk to wildcats.
{"title":"Endoparasites of peritoneal organs and skeletal muscles of the European wildcat (Felis silvestris) in Germany.","authors":"Katrin Bisterfeld, Marie-Kristin Raulf, Patrick Waindok, Andrea Springer, Johannes Lang, Michael Lierz, Ursula Siebert, Christina Strube","doi":"10.1186/s13071-024-06571-4","DOIUrl":"10.1186/s13071-024-06571-4","url":null,"abstract":"<p><strong>Background: </strong>For several decades, the European wildcat (Felis silvestris) has gradually been returning to the forests of Germany, mainly in the central and southwestern regions. To increase the knowledge about this threatened species, the endoparasite status of dead found specimens from Germany was surveyed.</p><p><strong>Methods: </strong>A total of 118 wildcats were examined for endoparasites in peritoneal organs and skeletal muscles. Owing to decomposition or incomplete carcasses, 104 gastrointestinal tracts (stomachs and intestines), 101 livers with gallbladders, 99 urinary bladders, as well as kidneys of 95 and skeletal muscles of 112 specimens were available for examination. All detected parasites were identified morphologically to genus or species level, followed by molecular examinations of one to ten specimens of each parasite species.</p><p><strong>Results: </strong>Overall endoparasite prevalence in peritoneal organs was 99.0% (103/104). Among the 99.0% (103/104) infected gastrointestinal tracts, the most frequent species were Toxocara cati (95.2% [99/104]), Hydatigera kamiyai (84.6% [88/104]), Mesocestoides litteratus (69.2% [72/104]), Strongyloides spp. (58.7% [61/104]), Cylicospirura petrowi (37.5% [39/104]), Ancylostoma tubaeforme (31.7% [33/104]), Capillaria putorii (24.0% [25/104]), and Echinococcus multilocularis (18.3% [19/104]). In 77.8% (77/99) of the urinary bladders, Capillaria plica and/or Capillaria feliscati were detected. Moreover, the liver fluke Metorchis bilis occurred in 2.0% (2/101) of the livers, and roundworm larvae (presumably Toxocara spp.) were detected in 33.0% (37/112) of the muscle samples.</p><p><strong>Conclusions: </strong>These results show a broad spectrum of endoparasite species infecting European wildcats in Germany. It might be assumed that some of the endoparasites could pose a risk to domestic cats (Felis catus) and humans through spillover events, or may be transmitted from domestic cats to the free-ranging population, posing a potential risk to wildcats.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"473"},"PeriodicalIF":3.0,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11575206/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142668601","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 : 2024-11-18DOI: 10.1186/s13071-024-06554-5
Monsuru A Adeleke, Kenneth N Opara, Hayward B Mafuyai, Bertram Ekejiuba Bright Nwoke, Olabanji A Surakat, Sunday B Akinde, Murphy Nwoke, Friday M Chikezie, Clement A Yaro, Ugagu Mmaduabuchi, Michael Igbe, Emeka Makata, Fatai Oyediran, Chukwuma Anyaike, Joseph Tongjura, Frances Hawkes, Zahra O Iwalewa
Background: Entomological data for onchocerciasis surveillance relies on sampling black flies through human landing collectors in the field and laboratory testing of the flies for infection using pooled screening O-150 PCR-ELISA assay. Both techniques require improvements. This study aimed to optimize the Esperanza Window Trap (EWT) for black fly collection. We tested alternative carbon dioxide (CO2) mimics to attract black flies to the traps. Additionally, we evaluated new quantitative PCR (qPCR) methods that target mitochondrial DNA markers and have been proposed to enhance the sensitivity and specificity for detecting Onchocerca volvulus infections in blackflies.
Methods: Traps baited with low, medium and high release rates of either 2-butanone or cyclopentanone as CO2 mimics were field tested against traps baited with organically generated CO2 in four ecological zones in Nigeria: Guinea savannah, derived savannah, rainforest and montane forest. The performance of EWTs baited with CO2 or in combination with 2-butanone (low release) were subsequently evaluated against the human landing collection (HLC). Trap scaling was also pilot tested by comparing two EWTs to a single HLC team. Collected black flies were used to test detection of O. volvulus in black flies using Ov ND5 real-time PCR (qPCR) compared to the conventional pool screening O-150 PCR.
Results: EWTs baited with 2-butanone caught similar numbers of black flies (Simulium damnosum s.l.) to those baited with CO2, while cyclopentanone collected significantly fewer flies in all locations. The low release of 2-butanone was the most effective overall, although HLCs collected higher numbers of black flies than EWT baited with CO2 either singly or in combination with low-release 2-butanone. The combination of two EWTs baited with CO2 and deployed 100 m apart from each other collected similar numbers of flies as one HLC. More black fly pools were positive for O. volvulus by Ov ND5 qPCR compared with O-150 PCR in derived savannah (31.15 vs. 15.57%), montane forest (11.54 vs. 0%) and rainforest (23.08 vs. 2.56%), with only one positive pool in Guinea savannah detected by both methods.
Conclusions: The 2-butanone has potential to be used in xenomonitoring as a standardized replacement for organically generated CO2. Ov ND5 qPCR detected more positive pools than O-150 PCR. The positive pools found in foci hitherto considered to have interrupted/eliminated onchocerciasis highlight the need for more sensitive and specific methods that support programmatic assessments to identify and combat recrudescence.
{"title":"Improving onchocerciasis elimination surveillance: trials of odour baited Esperanza Window Traps to collect black fly vectors and real-time qPCR detection of Onchocerca volvulus in black fly pools.","authors":"Monsuru A Adeleke, Kenneth N Opara, Hayward B Mafuyai, Bertram Ekejiuba Bright Nwoke, Olabanji A Surakat, Sunday B Akinde, Murphy Nwoke, Friday M Chikezie, Clement A Yaro, Ugagu Mmaduabuchi, Michael Igbe, Emeka Makata, Fatai Oyediran, Chukwuma Anyaike, Joseph Tongjura, Frances Hawkes, Zahra O Iwalewa","doi":"10.1186/s13071-024-06554-5","DOIUrl":"10.1186/s13071-024-06554-5","url":null,"abstract":"<p><strong>Background: </strong>Entomological data for onchocerciasis surveillance relies on sampling black flies through human landing collectors in the field and laboratory testing of the flies for infection using pooled screening O-150 PCR-ELISA assay. Both techniques require improvements. This study aimed to optimize the Esperanza Window Trap (EWT) for black fly collection. We tested alternative carbon dioxide (CO<sub>2</sub>) mimics to attract black flies to the traps. Additionally, we evaluated new quantitative PCR (qPCR) methods that target mitochondrial DNA markers and have been proposed to enhance the sensitivity and specificity for detecting Onchocerca volvulus infections in blackflies.</p><p><strong>Methods: </strong>Traps baited with low, medium and high release rates of either 2-butanone or cyclopentanone as CO<sub>2</sub> mimics were field tested against traps baited with organically generated CO<sub>2</sub> in four ecological zones in Nigeria: Guinea savannah, derived savannah, rainforest and montane forest. The performance of EWTs baited with CO<sub>2</sub> or in combination with 2-butanone (low release) were subsequently evaluated against the human landing collection (HLC). Trap scaling was also pilot tested by comparing two EWTs to a single HLC team. Collected black flies were used to test detection of O. volvulus in black flies using Ov ND5 real-time PCR (qPCR) compared to the conventional pool screening O-150 PCR.</p><p><strong>Results: </strong>EWTs baited with 2-butanone caught similar numbers of black flies (Simulium damnosum s.l.) to those baited with CO<sub>2</sub>, while cyclopentanone collected significantly fewer flies in all locations. The low release of 2-butanone was the most effective overall, although HLCs collected higher numbers of black flies than EWT baited with CO<sub>2</sub> either singly or in combination with low-release 2-butanone. The combination of two EWTs baited with CO<sub>2</sub> and deployed 100 m apart from each other collected similar numbers of flies as one HLC. More black fly pools were positive for O. volvulus by Ov ND5 qPCR compared with O-150 PCR in derived savannah (31.15 vs. 15.57%), montane forest (11.54 vs. 0%) and rainforest (23.08 vs. 2.56%), with only one positive pool in Guinea savannah detected by both methods.</p><p><strong>Conclusions: </strong>The 2-butanone has potential to be used in xenomonitoring as a standardized replacement for organically generated CO<sub>2</sub>. Ov ND5 qPCR detected more positive pools than O-150 PCR. The positive pools found in foci hitherto considered to have interrupted/eliminated onchocerciasis highlight the need for more sensitive and specific methods that support programmatic assessments to identify and combat recrudescence.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"471"},"PeriodicalIF":3.0,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11575192/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142668603","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 : 2024-11-17DOI: 10.1186/s13071-024-06563-4
Megan N Dillon, Barbara A Qurollo, Rachael Thomas, Madeline E Warren, Timothy A Mousseau, Jennifer A Betz, Norman J Kleiman, Matthew Breen
Background: The 1986 disaster at the Chornobyl Nuclear Power Plant released massive amounts of radioactive material into the local environment. In addition to radiation, remediation efforts and abandonment of military-industrial complexes contributed to contamination with heavy metals, organics, pesticides and other toxic chemicals. Numerous studies have evaluated the effects of this contamination on the local ecology. However, few studies have reported the effect of this contamination on vector-borne pathogens and their hosts. In this manuscript, we characterize tick-borne pathogen presence at two sample locations within the Chornobyl Exclusion Zone, one at the Nuclear Power Plant (NPP) and another 16 km away in Chornobyl City (CC).
Methods: Ticks and whole-blood samples were collected from free-breeding dogs captured at the NPP and CC. Endpoint PCR and quantitative PCR were used to identify tick species and to assess the presence of specific tick-borne pathogens, including Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, Babesia spp., Bartonella spp., Francisella tularensis and general Anaplasmataceae. A droplet digital PCR assay was developed for Babesia canis and A. phagocytophilum to evaluate their presence in dogs from the two populations. Pathogen prevalences between the two sample populations were compared by calculating Z-scores.
Results: Ticks were identified as Ixodes ricinus (n = 102) and Dermacentor reticulatus (n = 4). Overall, 56.9% of I. ricinus ticks were positive for at least one pathogen. A significantly higher prevalence of A. phagocytophilum and B. burgdorferi was found in ticks at the NPP (44.0% and 42.0%, respectively) compared to CC (23.1% and 19.2%, respectively). Babesia spp. (including B. canis and B. caballi) were detected in 8.8% ticks at similar proportions for both populations. Interestingly, we found a significantly lower level of A. phagocytophilum in dogs at the NPP (1.8%) than in dogs at CC (11.7%). In total, 24.3% of dogs were positive for B. canis, evenly distributed across the two populations.
Conclusions: The results of this study show contrasting pathogen prevalence in both ticks and dogs at the NPP and CC, which may reflect the differential exposures at the two locations. This work adds an important new component to our understanding of the consequences of prolonged exposure to environmental contamination on the wildlife and ecology within the Chornobyl Exclusion Zone.
{"title":"Contrasting pathogen prevalence between tick and dog populations at Chornobyl.","authors":"Megan N Dillon, Barbara A Qurollo, Rachael Thomas, Madeline E Warren, Timothy A Mousseau, Jennifer A Betz, Norman J Kleiman, Matthew Breen","doi":"10.1186/s13071-024-06563-4","DOIUrl":"10.1186/s13071-024-06563-4","url":null,"abstract":"<p><strong>Background: </strong>The 1986 disaster at the Chornobyl Nuclear Power Plant released massive amounts of radioactive material into the local environment. In addition to radiation, remediation efforts and abandonment of military-industrial complexes contributed to contamination with heavy metals, organics, pesticides and other toxic chemicals. Numerous studies have evaluated the effects of this contamination on the local ecology. However, few studies have reported the effect of this contamination on vector-borne pathogens and their hosts. In this manuscript, we characterize tick-borne pathogen presence at two sample locations within the Chornobyl Exclusion Zone, one at the Nuclear Power Plant (NPP) and another 16 km away in Chornobyl City (CC).</p><p><strong>Methods: </strong>Ticks and whole-blood samples were collected from free-breeding dogs captured at the NPP and CC. Endpoint PCR and quantitative PCR were used to identify tick species and to assess the presence of specific tick-borne pathogens, including Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, Babesia spp., Bartonella spp., Francisella tularensis and general Anaplasmataceae. A droplet digital PCR assay was developed for Babesia canis and A. phagocytophilum to evaluate their presence in dogs from the two populations. Pathogen prevalences between the two sample populations were compared by calculating Z-scores.</p><p><strong>Results: </strong>Ticks were identified as Ixodes ricinus (n = 102) and Dermacentor reticulatus (n = 4). Overall, 56.9% of I. ricinus ticks were positive for at least one pathogen. A significantly higher prevalence of A. phagocytophilum and B. burgdorferi was found in ticks at the NPP (44.0% and 42.0%, respectively) compared to CC (23.1% and 19.2%, respectively). Babesia spp. (including B. canis and B. caballi) were detected in 8.8% ticks at similar proportions for both populations. Interestingly, we found a significantly lower level of A. phagocytophilum in dogs at the NPP (1.8%) than in dogs at CC (11.7%). In total, 24.3% of dogs were positive for B. canis, evenly distributed across the two populations.</p><p><strong>Conclusions: </strong>The results of this study show contrasting pathogen prevalence in both ticks and dogs at the NPP and CC, which may reflect the differential exposures at the two locations. This work adds an important new component to our understanding of the consequences of prolonged exposure to environmental contamination on the wildlife and ecology within the Chornobyl Exclusion Zone.</p>","PeriodicalId":19793,"journal":{"name":"Parasites & Vectors","volume":"17 1","pages":"470"},"PeriodicalIF":3.0,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11571660/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142648559","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}