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Eamsobhana P, Yong HS, Boonyong S, Wanachiwanawin D, Tungtrongchitr A. Genetic diversity and identity of Ascaris worms from human and pig hosts in Thailand. Vet Parasitol Reg Stud Reports 2022; 33:100752. [PMID: 35820723 DOI: 10.1016/j.vprsr.2022.100752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 05/05/2022] [Accepted: 06/09/2022] [Indexed: 06/15/2023]
Abstract
Ascaris roundworms are of public health and socio-economic importance worldwide. They are conventionally attributed to two taxa - A. lumbricoides infecting principally human and A. suum infecting principally pig. Phylogenomic analysis has revealed that Ascaris worms from both human and pig are represented in Clades A and B. A recent study indicates that the Ascaris worms from human and pig in Thailand belong to Clade A. We examined adult Ascaris worms from human and pig in Thailand by means of the partial sequences of three mitochondrial genes (cox1, cox2 and nad1) and concatenation of these genes. Phylogenomic analysis indicates that two isolates (H1,H2) of A. lumbricoides from human belonged to Clade B; one isolate (H3) belonged to Clade A (based on cox1, cox2 and concatenated sequences) or as an outlier to Clades A and B (based on nad1 sequences). All the eight isolates of A. suum from pig clustered in Clade A. The partial nad1 and the concatenated sequences revealed two lineages of A. suum isolates which were distinct from the two A. lumbricoides isolates of Clade B. It is evident that greater genetic diversity, and a more robust phylogeny, could be uncovered by the application of multiple genes. In sum, the present study reveals the presence in Thailand of A. lumbricoides from human in Clades A and B which necessitates appropriate treatment and control measures; Clades A and B have been reported to contain haplotypes of Ascaris worms from both human and pig in other parts of the world. A country wide study is needed to elucidate the identity, distribution, prevalence, cross transmission, genetic diversity and phylogeny of the Ascaris worms in Thailand.
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Affiliation(s)
- Praphathip Eamsobhana
- Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
| | - Hoi-Sen Yong
- Institute of Biological Sciences, Faculty of Science, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Sudarat Boonyong
- Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Darawan Wanachiwanawin
- Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Anchalee Tungtrongchitr
- Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
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Development of allele-specific PCR methodology (AS-PCR) to screening A. lumbricoides and A. suum. Parasitol Res 2022; 121:2389-2397. [PMID: 35710846 DOI: 10.1007/s00436-022-07572-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 06/03/2022] [Indexed: 10/18/2022]
Abstract
Ascaris lumbricoides and Ascaris suum are described as helminths that infect humans and pigs, respectively. It is estimated that infection by A. lumbricoides affects about 447 million individuals living in tropical regions of developing countries. However, there is an increasing number of cases of human ascariasis in countries with no recent history of autochthonous infection by A. lumbricoides. In these places, pigs have been incriminated as the main source of human infection. Conventional parasitological diagnosis does not allow species-specific identification, and the real epidemiological scenario of human and swine ascariasis is still uncertain. Therefore, this work presents the application of a species-specific molecular diagnosis, based on the allele-specific PCR methodology (AS-PCR), using the Internal Transcript Space 1 (ITS-1) of the ribosomal DNA, as a target for differentiating between the two species, using DNA obtained from eggs. To validate the methodology, stool samples positive for Ascaris spp, were obtained from 68 humans from seven Brazilian states and from six pigs from the state of Minas Gerais. All samples obtained from humans were genotyped as A. lumbricoides and all samples obtained from swine were genotyped as A. suum. These results are in agreement with the literature, which demonstrates that in most endemic regions, transmission cycles are separate. Therefore, the execution of this work allowed the availability of a useful methodology for the differential diagnosis of the species, which may contribute to the characterization of the real epidemiological profile of human and swine ascariasis, and to the implementation of future control strategies.
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Nkouayep VR, McManus DP, Mbida M, Gordon CA, Nejsum P. Molecular epidemiology of Ascaris species recovered from humans and pigs in Cameroon. Trans R Soc Trop Med Hyg 2022; 116:949-958. [PMID: 35385862 DOI: 10.1093/trstmh/trac020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 01/22/2022] [Accepted: 03/10/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND In Cameroon, considerable research has been conducted on human ascariasis, but no studies have been undertaken to determine whether pigs contribute to the persistence of the infection in children or to unravel the evolutionary relationship between human-derived and pig-derived Ascaris. METHODS DNA was extracted from adult Ascaris worms collected from humans and pigs. Segments of the cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 1 (nad1) genes were sequenced and analysed for 83 worms to dissect the local transmission dynamics of Ascaris in Cameroon. RESULTS The data showed high genetic diversity and revealed demographically expanding populations in the human and pig Ascaris samples. A restricted gene flow between Ascaris lumbricoides and Ascaris suum populations correlating with the preference for humans and pigs, respectively, as hosts was evident. Phylogenetic analyses and haplotype networks split the haplotypes into two major clusters, A and B. However, support for cross-transmission between hosts and hybridization were revealed through shared haplotypes among worms from both hosts. CONCLUSIONS This study provides useful baseline information for future studies of the genetics of Ascaris in Cameroon and suggests that effective and sustainable control of human ascariasis should target both human and pig hosts.
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Affiliation(s)
- Vanessa R Nkouayep
- Research Unit of Biology and Applied Ecology, Department of Animal Biology, Faculty of Science, University of Dschang, P.O. Box 067, Dschang, Cameroon
| | - Donald P McManus
- Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Mpoame Mbida
- Research Unit of Biology and Applied Ecology, Department of Animal Biology, Faculty of Science, University of Dschang, P.O. Box 067, Dschang, Cameroon
| | - Catherine A Gordon
- Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Peter Nejsum
- Department of Clinical Medicine, Faculty of Health, Aarhus University, Palle Juul-Jensens Boulevard 99, 8200 Aarhus N, Denmark
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HODDA M. Phylum Nematoda: trends in species descriptions, the documentation of diversity, systematics, and the species concept. Zootaxa 2022; 5114:290-317. [DOI: 10.11646/zootaxa.5114.1.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Indexed: 11/04/2022]
Abstract
This paper summarizes the trends in nematode species description and systematics emerging from a comparison of the latest comprehensive classification and census of Phylum Nematoda (Hodda 2022a, b) with earlier classifications (listed in Hodda 2007). It also offers some general observations on trends in nematode systematics emerging from the review of the voluminous literature used to produce the classification. The trends in nematodes can be compared with developments in the systematics of other organisms to shed light on many of the general issues confronting systematists now and into the future.
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Human-type and pig-type Ascaris hybrids found in pigs. Vet Parasitol 2022; 302:109646. [PMID: 34999317 DOI: 10.1016/j.vetpar.2021.109646] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 12/30/2021] [Accepted: 12/30/2021] [Indexed: 01/14/2023]
Abstract
The discovery of hybrids between Ascaris lumbricoides and Ascaris suum has complicated our understanding of the relationship between the two species. We examined the same Ascaris specimens (48 from humans and 48 from pigs) using two methods: microsatellite markers combined with Bayesian clustering and PCR-RFLP of the nuclear internal transcribed spacer region. The results obtained by the two methods were inconsistent but showed that hybrid Ascaris identified through both approaches could infect pigs. The results of this study suggest that PCR-RFLP of ITS alone is not suitable for molecular identification of human-type and pig-type Ascaris hybrids. Use of multiple SSR markers combined with Bayesian analysis was the most reliable method in our study. Our results indicate that, in addition to host-specific Ascaris types, there may be some that do not show host specificity. Our results show for the first time that hybrid individuals can infect pigs as well as humans. This study has important theoretical and practical implications, including suggesting the need to re-evaluate long-term ascariasis control strategies.
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Genetic background affects the mucosal SIgA levels, parasite burden, lung inflammation and susceptibility of male mice to Ascaris suum infection. Infect Immun 2021; 90:e0059521. [PMID: 34807734 DOI: 10.1128/iai.00595-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ascariasis is a neglected tropical disease, widespread in the world and causing important socioeconomic impacts. The presence of various stages of worm development in the pulmonary and intestinal mucosa induces a humoral and cellular immune response. However, although there is much evidence of the protective role of mucosal immunity against various pathogens, including helminthes, there is still a gap in the knowledge about the immune response and the mechanisms of action that are involved in protection against diseases, especially in the initial phase of ascariasis. Then, the aim of this study was to evaluate the kinetic aspects of the immune parasitological parameters in intestinal and pulmonary mucosa in male mice with early ascariasis. Therefore, two mice strains showed a different susceptibility to ascariasis (BALB/c and C57BL6/j), when experimentally infected with 2,500 infective eggs of Ascaris suum from time-point 0 and the immune parasitological parameters evaluated each two days after infection, during the period of 12 days. The results were suggestive of a synergetic action of intestinal and pulmonary SIgA contributing for the protection against early ascariasis by reducing the amount of migrating larval as well as the influx of leukocytes in the lung and the consequent impair of the pulmonary capacity.
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Zhou C, Guo T, Deng Y, He J, Ouyang S, Wu X. Mitochondrial phylogenomics of human-type Ascaris, pig-type Ascaris, and hybrid Ascaris populations. Vet Parasitol 2020; 287:109256. [PMID: 33053491 DOI: 10.1016/j.vetpar.2020.109256] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/25/2020] [Accepted: 09/27/2020] [Indexed: 12/15/2022]
Abstract
Ascaris lumbricoides and Ascaris suum are parasitic nematodes in human and pig intestines. The two species can cross infect and produce hybrids, which contribute to the controversy concerning the taxonomy of A. lumbricoides and A. suum. The purpose of this study was to investigate the microevolutionary process and evolutionary history of human-type Ascaris, pig-type Ascaris, and hybrid Ascaris and provide a theoretical basis for the prevention and control of human and animal ascariasis. The mitochondrial phylogenomics of human-type Ascaris (n = 5), pig-type Ascaris (n = 6), and hybrid Ascaris (n = 6) populations were analyzed using high-throughput sequencing technology. The mitochondrial genomes of human-type Ascaris, pig-type Ascaris, and hybrid Ascaris contained 36 genes (atp8 was missing), including 12 protein-coding genes, 2 rRNA genes, and 22 tRNA genes. All genes were located on the heavy chain. The initiation codons used for protein-coding genes were ATT and TTG and the termination codons were TAA and TAG. The base distribution showed obvious AT preference. The phylogenetic tree based on the Ascaris mitochondrial genomes showed three main clusters (A, B, and C). The Ascaris populations sequenced in this study were all gathered in cluster B. The human-type and hybrid Ascaris populations belonged to different sub-clusters, but the pig-type Ascaris population was more scattered. The mitochondrial genome sequences of the 17 Ascaris individuals in this study did not differ much. The results of this study indicate that Ascaris populations were geographically isolated before host shift. In addition, the data show that there are differences between hybrid Ascaris, human-type Ascaris, and pig-type Ascaris. The information has important theoretical significance and application value.
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Affiliation(s)
- Chunhua Zhou
- School of Life Sciences, Nanchang University, Nanchang 330031, People's Republic of China.
| | - Ting Guo
- School of Life Sciences, Nanchang University, Nanchang 330031, People's Republic of China
| | - Yuanyu Deng
- School of Life Sciences, Nanchang University, Nanchang 330031, People's Republic of China
| | - Jingjing He
- School of Life Sciences, Nanchang University, Nanchang 330031, People's Republic of China
| | - Shan Ouyang
- School of Life Sciences, Nanchang University, Nanchang 330031, People's Republic of China
| | - Xiaoping Wu
- School of Life Sciences, Nanchang University, Nanchang 330031, People's Republic of China.
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Zawawi A, Else KJ. Soil-Transmitted Helminth Vaccines: Are We Getting Closer? Front Immunol 2020; 11:576748. [PMID: 33133094 PMCID: PMC7565266 DOI: 10.3389/fimmu.2020.576748] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 09/02/2020] [Indexed: 01/07/2023] Open
Abstract
Parasitic helminths infect over one-fourth of the human population resulting in significant morbidity, and in some cases, death in endemic countries. Despite mass drug administration (MDA) to school-aged children and other control measures, helminth infections are spreading into new areas. Thus, there is a strong rationale for developing anthelminthic vaccines as cost-effective, long-term immunological control strategies, which, unlike MDA, are not haunted by the threat of emerging drug-resistant helminths nor limited by reinfection risk. Advances in vaccinology, immunology, and immunomics include the development of new tools that improve the safety, immunogenicity, and efficacy of vaccines; and some of these tools have been used in the development of helminth vaccines. The development of anthelminthic vaccines is fraught with difficulty. Multiple lifecycle stages exist each presenting stage-specific antigens. Further, helminth parasites are notorious for their ability to dampen down and regulate host immunity. One of the first significant challenges in developing any vaccine is identifying suitable candidate protective antigens. This review explores our current knowledge in lead antigen identification and reports on recent pre-clinical and clinical trials in the context of the soil-transmitted helminths Trichuris, the hookworms and Ascaris. Ultimately, a multivalent anthelminthic vaccine could become an essential tool for achieving the medium-to long-term goal of controlling, or even eliminating helminth infections.
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Affiliation(s)
- Ayat Zawawi
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia,*Correspondence: Ayat Zawawi
| | - Kathryn J. Else
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine, and Health, School of Biological Sciences, Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester, United Kingdom,Kathryn J. Else
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Zhou C, Chen J, Niu H, Ouyang S, Wu X. Study on the population evolution of Ascaris lumbricoides and Ascaris suum based on whole genome resequencing. Vet Parasitol 2020; 279:109062. [DOI: 10.1016/j.vetpar.2020.109062] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 02/21/2020] [Accepted: 02/24/2020] [Indexed: 12/27/2022]
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Abstract
Abstract
Ascariasis is a neglected tropical disease, caused by Ascaris lumbricoides, affecting 800 million people worldwide. Studies focused on the early stage of parasite infection, occurring in the gut, liver and lungs, require the use of a mouse model. In these models, the porcine ascarid, Ascaris suum, is often used. The results obtained from these studies are then used to draw conclusions about A. lumbricoides infections in humans. In the present study, we sought to compare larval migration of A. suum and A. lumbricoides in mouse models. We used a previously developed mouse model of ascariasis, which consists of two mouse strains, where one mouse strain – C57BL/6J – is a model for relative susceptibility and the other – CBA/Ca – for relative resistance. Mice of both strains were infected with either A. suum or A. lumbricoides. The larval burden was assessed in two key organs, the liver and lungs, starting at 6 h post infection (p.i.) and ending on day 8 p.i. Additionally, we measured the larval size of each species (μm) at days 6, 7 and 8 p.i. in the lungs. We found that larval burden in the liver is significantly higher for A. lumbricoides than for A. suum. However, the inverse is true in the lungs. Additionally, our results showed a reduced larval size for A. lumbricoides compared to A. suum.
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Eighteenth Century Urban Growth and Parasite Spread at the Fortress of Louisbourg, Nova Scotia, Canada. BIOARCHAEOLOGY AND SOCIAL THEORY 2020. [DOI: 10.1007/978-3-030-53417-2_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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Abstract
AbstractAscaris sp. is a soil-transmitted helminth (STH) significantly affecting the health of human and swine populations. Health inequities and poverty, with resulting deficiencies in water, sanitation and hygiene, are directly associated with Ascaris lumbricoides prevalence in humans. Resource constraints also lead to small-scale livestock production under unsanitary conditions. Free-ranging pigs, for instance, are exposed to a number of infectious agents, among which Ascaris suum is one of the most common. Under these conditions, close proximity between people and pigs can result in cross-contamination; that is, pigs harbouring human Ascaris and vice versa. Moreover, the potential interbreeding between these two Ascaris species has been demonstrated. The present study analysed Ascaris worms obtained from children and pigs in Honduras. Adult worms were collected from stool samples of children after pharmacological treatment, and from pigs’ intestines after slaughter for commercial purposes at a local abattoir. A nuclear ribosomal internal transcribed spacer (ITS) region was amplified by polymerase chain reaction (PCR) and digested with a restriction enzyme in order to separate putative human- and pig-derived Ascaris isolates. PCR products were also sequenced, and cladograms were constructed. All parasites isolated from children showed the typical human-derived genotype of Ascaris, whereas 91% of parasites from pigs showed the expected pig-derived genotype. Cross-infections between hosts were not demonstrated in this study. Nine per cent of pig-derived worms showed a restriction band pattern highly suggestive of a hybrid human–pig Ascaris genotype. These results contribute to the understanding of ascariasis epidemiology and its zoonotic potential in a highly endemic region.
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Van Horn R, Clay K. MITOCHONDRIAL DNA VARIATION IN THE FUNGUS
ATKINSONELLA HYPOXYLON
INFECTING SYMPATRIC
DANTHONIA
GRASSES. Evolution 2017; 49:360-371. [DOI: 10.1111/j.1558-5646.1995.tb02248.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/1993] [Accepted: 04/22/1994] [Indexed: 11/30/2022]
Affiliation(s)
- Randall Van Horn
- Department of Biology Indiana University Bloomington Indiana 47405‐6801
| | - Keith Clay
- Department of Biology Indiana University Bloomington Indiana 47405‐6801
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Jesudoss Chelladurai J, Murphy K, Snobl T, Bader C, West C, Thompson K, Brewer MT. Molecular Epidemiology of Ascaris Infection Among Pigs in Iowa. J Infect Dis 2016; 215:131-138. [PMID: 28077590 DOI: 10.1093/infdis/jiw507] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 10/15/2016] [Indexed: 11/12/2022] Open
Abstract
Ascaris is a large roundworm parasite that infects humans and pigs throughout the world. Molecular markers have been used to study parasite transmission in Ascaris-endemic and -nonendemic regions of the world. In the United States, ascariasis still persists in commercial swine and has been designated a neglected disease of poverty in humans. However, relatively few data are available for evaluation of zoonotic transmission. In the present study, we obtained adult worms from abattoirs and characterized each worm on the basis of the gene encoding nuclear internal transcribed sequence (ITS) and mitochondrial cox1 Restriction fragment-length polymorphism analysis of ITS revealed swine, human, and hybrid genotypes. cox1 sequences were compared to all complete sequences available in GenBank, and haplotype analysis demonstrated 92 haplotypes worldwide. Sequences from the parasites in this study represented 10 haplotypes, including 6 new haplotypes that have not been previously described. Our results indicate that anthropozoonotic transmission has occurred in the past, resulting in the presence of human genotypes in pigs and supporting further investigation of zoonotic Ascaris transmission in the United States.
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Affiliation(s)
| | - Kaitlyn Murphy
- Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University, Ames
| | - Tymbrie Snobl
- Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University, Ames
| | - Christopher Bader
- Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University, Ames
| | - Cody West
- Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University, Ames
| | - Kylie Thompson
- Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University, Ames
| | - Matthew T Brewer
- Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University, Ames
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Gasser RB, Korhonen PK, Zhu XQ, Young ND. Harnessing the Toxocara Genome to Underpin Toxocariasis Research and New Interventions. ADVANCES IN PARASITOLOGY 2016; 91:87-110. [PMID: 27015948 DOI: 10.1016/bs.apar.2015.12.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Parasitic worms, such as flatworms (platyhelminths) and roundworms (nematodes), cause substantial morbidity and mortality in animals and people globally. The ascaridoid nematode Toxocara canis is a zoonotic parasite of socioeconomic significance worldwide. In humans, this worm causes toxocariasis (disease) mainly in underprivileged communities in both the developed and developing worlds. While reasonably well studied from clinical and epidemiological perspectives, little is understood about the molecular biology of T. canis, its relationship with its hosts and the disease that it causes. However, a recent report of the draft genome and transcriptomes of T. canis should underpin many fundamental and applied research areas in the future. The present article gives a background on Toxocara and toxocariasis, a brief account of diagnostic approaches for specific identification and genetic analysis, and gives a perspective on the impact that the genome of T. canis and advanced molecular technologies could have on our understanding of the parasite and the diseases that it causes as well as the design of new and improved approaches for the diagnosis, treatment and control of toxocariasis.
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Schneider R, Auer H. Incidence of Ascaris suum-specific antibodies in Austrian patients with suspected larva migrans visceralis (VLM) syndrome. Parasitol Res 2015; 115:1213-9. [DOI: 10.1007/s00436-015-4857-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 11/27/2015] [Indexed: 10/22/2022]
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Vazquez-Prieto S, Vilas R, Paniagua E, Ubeira FM. Influence of life history traits on the population genetic structure of parasitic helminths: a minireview. Folia Parasitol (Praha) 2015; 62. [DOI: 10.14411/fp.2015.060] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 09/22/2015] [Indexed: 11/19/2022]
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Bass D, Stentiford GD, Littlewood D, Hartikainen H. Diverse Applications of Environmental DNA Methods in Parasitology. Trends Parasitol 2015; 31:499-513. [DOI: 10.1016/j.pt.2015.06.013] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 06/16/2015] [Accepted: 06/24/2015] [Indexed: 01/05/2023]
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Cwiklinski K, Dalton JP, Dufresne PJ, La Course J, Williams DJ, Hodgkinson J, Paterson S. The Fasciola hepatica genome: gene duplication and polymorphism reveals adaptation to the host environment and the capacity for rapid evolution. Genome Biol 2015; 16:71. [PMID: 25887684 PMCID: PMC4404566 DOI: 10.1186/s13059-015-0632-2] [Citation(s) in RCA: 190] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 03/13/2015] [Indexed: 12/30/2022] Open
Abstract
Background The liver fluke Fasciola hepatica is a major pathogen of livestock worldwide, causing huge economic losses to agriculture, as well as 2.4 million human infections annually. Results Here we provide a draft genome for F. hepatica, which we find to be among the largest known pathogen genomes at 1.3 Gb. This size cannot be explained by genome duplication or expansion of a single repeat element, and remains a paradox given the burden it may impose on egg production necessary to transmit infection. Despite the potential for inbreeding by facultative self-fertilisation, substantial levels of polymorphism were found, which highlights the evolutionary potential for rapid adaptation to changes in host availability, climate change or to drug or vaccine interventions. Non-synonymous polymorphisms were elevated in genes shared with parasitic taxa, which may be particularly relevant for the ability of the parasite to adapt to a broad range of definitive mammalian and intermediate molluscan hosts. Large-scale transcriptional changes, particularly within expanded protease and tubulin families, were found as the parasite migrated from the gut, across the peritoneum and through the liver to mature in the bile ducts. We identify novel members of anti-oxidant and detoxification pathways and defined their differential expression through infection, which may explain the stage-specific efficacy of different anthelmintic drugs. Conclusions The genome analysis described here provides new insights into the evolution of this important pathogen, its adaptation to the host environment and external selection pressures. This analysis also provides a platform for research into novel drugs and vaccines. Electronic supplementary material The online version of this article (doi:10.1186/s13059-015-0632-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Krystyna Cwiklinski
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK. .,School of Biological Sciences, Medical Biology Centre, Queen's University of Belfast, Belfast, Northern Ireland, UK.
| | - John Pius Dalton
- School of Biological Sciences, Medical Biology Centre, Queen's University of Belfast, Belfast, Northern Ireland, UK. .,Institute of Parasitology, McGill University, Montreal, Quebec, Canada.
| | - Philippe J Dufresne
- Institute of Parasitology, McGill University, Montreal, Quebec, Canada. .,Institut National de Santé Publique du Québec, Montreal, Quebec, Canada.
| | | | - Diana Jl Williams
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK.
| | - Jane Hodgkinson
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK.
| | - Steve Paterson
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK.
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Modelling the effects of mass drug administration on the molecular epidemiology of schistosomes. ADVANCES IN PARASITOLOGY 2015; 87:293-327. [PMID: 25765198 DOI: 10.1016/bs.apar.2014.12.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
As national governments scale up mass drug administration (MDA) programs aimed to combat neglected tropical diseases (NTDs), novel selection pressures on these parasites increase. To understand how parasite populations are affected by MDA and how to maximize the success of control programmes, it is imperative for epidemiological, molecular and mathematical modelling approaches to be combined. Modelling of parasite population genetic and genomic structure, particularly of the NTDs, has been limited through the availability of only a few molecular markers to date. The landscape of infectious disease research is being dramatically reshaped by next-generation sequencing technologies and our understanding of how repeated selective pressures are shaping parasite populations is radically altering. Genomics can provide high-resolution data on parasite population structure, and identify how loci may contribute to key phenotypes such as virulence and/or drug resistance. We discuss the incorporation of genetic and genomic data, focussing on the recently sequenced Schistosoma spp., into novel mathematical transmission models to inform our understanding of the impact of MDA and other control methods. We summarize what is known to date, the models that exist and how population genetics has given us an understanding of the effects of MDA on the parasites. We consider how genetic and genomic data have the potential to shape future research, highlighting key areas where data are lacking, and how future molecular epidemiology knowledge can aid understanding of transmission dynamics and the effects of MDA, ultimately informing public health policy makers of the best interventions for NTDs.
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Schneider R, Obwaller A, Auer H. Immunoblot for the detection of Ascaris suum-specific antibodies in patients with visceral larva migrans (VLM) syndrome. Parasitol Res 2014; 114:305-10. [PMID: 25367210 DOI: 10.1007/s00436-014-4196-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 10/16/2014] [Indexed: 11/26/2022]
Abstract
Visceral larva migrans (VLM) syndrome caused by Toxocara canis larvae was first described in the 1950s. The role of other nematode larvae, i.e. the pig roundworm Ascaris suum as a causative agent of visceral larva migrans-associated symptoms like general malaise, cough, liver dysfunction, hypereosinophilia with hepatomegaly and/or pneumonia, was discussed controversially during the last decades. Recent serological screening studies for specific A. suum antibodies carried out in the Netherlands and Sweden yielded remarkable high seroprevalences, while a number of case reports from Japan report pulmonal, hepatic and cerebral symptoms caused by A. suum larvae after ingestion of infected raw meat (liver) or contaminated vegetables. We present here a sensitive and specific larval excretory-secretory (E/S) antigen-based immunoblot (As-IB) for the serodiagnosis of A. suum-infected patients suffering from symptoms associated to the VLM syndrome. In total, 34 sera from patients with hypereosinophilia and other clinical symptoms associated to the VLM syndrome tested negative for Toxocara sp. antibodies but positive in our newly established As-IB, 30 sera from healthy volunteers, 53 sera from patients with clinically and serologically confirmed toxocarosis and other helminthoses as well as 3 sera from patients with intestinal ascariosis due to Ascaris lumbricoides were included in the study. When evaluated with 30 sera from healthy volunteers and 53 sera from patients suffering from different helminthoses, the calculated specificity of our new As-IB is 95%. Problems hampering the establishment of simple serological screening tests for specific A. suum antibodies, like extensive antigenic similarities between the nematodes Ascaris and Toxocara or the absence of suitable experimental animals, are discussed. We assume that specific serological testing for antibodies of A. suum is very important for the treatment of individual patients on one hand and seroepidemiological investigations will help to clarify routes of transmission on the other hand. Further studies will be necessary to learn more about the extent of A. suum as a causative agent of the VLM syndrome and the role of pigs and their manure as the main source of human Ascaris infections in Austria and other industrialized countries.
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Affiliation(s)
- Renate Schneider
- Department of Medical Parasitology, Institute of Specific Prophylaxis and Tropical Medicine, Center of Pathophysiology, Infectiology and Immunology, Medical University Vienna, Kinderspitalgasse 15, 1095, Vienna, Austria
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Cavallero S, Costa A, Caracappa S, Gambetta B, D'Amelio S. Putative hybrids between two Anisakis cryptic species: molecular genotyping using High Resolution Melting. Exp Parasitol 2014; 146:87-93. [PMID: 25241034 DOI: 10.1016/j.exppara.2014.08.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 08/18/2014] [Accepted: 08/26/2014] [Indexed: 11/19/2022]
Abstract
The genus Anisakis includes nine recognized species and the complex of cryptic species Anisakis simplex s. l. is often associated with the human disease known as anisakiasis. During the last decades the use of nuclear ribosomal ITS allowed the identification and description of numerous anisakid nematodes and the discovery of recombinant genotypes or putative hybrids even in other parasitic helminths, such as those between A. simplex sensu stricto and A. pegreffii. The existence of pure hybrids of the two sibling species has been long debated due to the large recovery of larval forms from sympatric areas and the rare observation of adult hybrids. The aims of the present report were to identify anisakid nematodes collected from Stenella coeruleoalba using PCR-RFLP of ITS and to focus the interest on hybrid forms using a High Resolution Melting (HRM) and direct sequencing analyses, since the new record of putative hybrid at adult stage. The PCR-RFLP analysis enabled to identify A. simplex s.s., A. pegreffii, the heterozygous genotype of the two species and A. physeteris. The use of the genotyping approach based on HRM confirmed the profiles of the two species A. simplex s.s. and A. pegreffii, and of the hybrid individuals. The new record of adult hybrids in definitive hosts rekindles the long debate about their existence and their evolutionary meaning. Since the reproductive isolation between A. simplex s.s. and A. pegreffii is the assumption for their existence as separated species, the use of alternative molecular markers and population genetic studies on adult anisakids are recommended.
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Affiliation(s)
- S Cavallero
- Department of Public Health and Infectious Diseases, Section of Parasitology, Sapienza University of Rome, Italy.
| | - A Costa
- Istituto Zooprofilattico Sperimentale della Sicilia, Italy
| | - S Caracappa
- Istituto Zooprofilattico Sperimentale della Sicilia, Italy
| | - B Gambetta
- Department of Public Health and Infectious Diseases, Section of Parasitology, Sapienza University of Rome, Italy
| | - S D'Amelio
- Department of Public Health and Infectious Diseases, Section of Parasitology, Sapienza University of Rome, Italy
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Betson M, Nejsum P, Bendall RP, Deb RM, Stothard JR. Molecular epidemiology of ascariasis: a global perspective on the transmission dynamics of Ascaris in people and pigs. J Infect Dis 2014; 210:932-41. [PMID: 24688073 PMCID: PMC4136802 DOI: 10.1093/infdis/jiu193] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Background. The roundworm Ascaris lumbricoides infects 0.8 billion people worldwide, and Ascaris suum infects innumerable pigs across the globe. The extent of natural cross-transmission of Ascaris between pig and human hosts in different geographical settings is unknown, warranting investigation. Methods. Adult Ascaris organisms were obtained from humans and pigs in Europe, Africa, Asia, and Latin America. Barcodes were assigned to 536 parasites on the basis of sequence analysis of the mitochondrial cytochrome c oxidase I gene. Genotyping of 410 worms was also conducted using a panel of microsatellite markers. Phylogenetic, population genetic, and Bayesian assignment methods were used for analysis. Results. There was marked genetic segregation between worms originating from human hosts and those originating from pig hosts. However, human Ascaris infections in Europe were of pig origin, and there was evidence of cross-transmission between humans and pigs in Africa. Significant genetic differentiation exists between parasite populations from different countries, villages, and hosts. Conclusions. In conducting an analysis of variation within Ascaris populations from pig and human hosts across the globe, we demonstrate that cross-transmission takes place in developing and developed countries, contingent upon epidemiological potential and local phylogeography. Our results provide novel insights into the transmission dynamics and speciation of Ascaris worms from humans and pigs that are of importance for control programs.
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Affiliation(s)
- Martha Betson
- Department of Production and Population Health, Royal Veterinary College, Hatfield, Hertfordshire, United Kingdom Department of Parasitology, Pembroke Place, Liverpool School of Tropical Medicine, United Kingdom
| | - Peter Nejsum
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | | | - Rinki M Deb
- Department of Parasitology, Pembroke Place, Liverpool School of Tropical Medicine, United Kingdom
| | - J Russell Stothard
- Department of Parasitology, Pembroke Place, Liverpool School of Tropical Medicine, United Kingdom
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Zhan B, Beaumier CM, Briggs N, Jones KM, Keegan BP, Bottazzi ME, Hotez PJ. Advancing a multivalent 'Pan-anthelmintic' vaccine against soil-transmitted nematode infections. Expert Rev Vaccines 2014; 13:321-31. [PMID: 24392641 PMCID: PMC3934375 DOI: 10.1586/14760584.2014.872035] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ascaris lumbricoides The Sabin Vaccine Institute Product Development Partnership is developing a Pan-anthelmintic vaccine that simultaneously targets the major soil-transmitted nematode infections, in other words, ascariasis, trichuriasis and hookworm infection. The approach builds off the current bivalent Human Hookworm Vaccine now in clinical development and would ultimately add both a larval Ascaris lumbricoides antigen and an adult-stage Trichuris trichiura antigen from the parasite stichosome. Each selected antigen would partially reproduce the protective immunity afforded by UV-attenuated Ascaris eggs and Trichuris stichosome extracts, respectively. Final antigen selection will apply a ranking system that includes the evaluation of expression yields and solubility, feasibility of process development and the absence of circulating antigen-specific IgE among populations living in helminth-endemic regions. Here we describe a five year roadmap for the antigen discovery, feasibility and antigen selection, which will ultimately lead to the scale-up expression, process development, manufacture, good laboratory practices toxicology and preclinical evaluation, ultimately leading to Phase 1 clinical testing.
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Affiliation(s)
- Bin Zhan
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, National School of Tropical Medicine, Baylor College of Medicine , Houston, TX , USA
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Parvatham K, Veerakumari L. Drug target prediction using elementary mode analysis in Ascaris lumbricoides energy metabolism. BIOTECHNOL BIOPROC E 2013. [DOI: 10.1007/s12257-012-0390-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Cavallero S, Snabel V, Pacella F, Perrone V, D'Amelio S. Phylogeographical studies of Ascaris spp. based on ribosomal and mitochondrial DNA sequences. PLoS Negl Trop Dis 2013; 7:e2170. [PMID: 23593529 PMCID: PMC3623706 DOI: 10.1371/journal.pntd.0002170] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 03/08/2013] [Indexed: 11/25/2022] Open
Abstract
Background The taxonomic distinctiveness of Ascaris lumbricoides and A. suum, two of the world's most significant nematodes, still represents a much-debated scientific issue. Previous studies have described two different scenarios in transmission patterns, explained by two hypotheses: (1) separated host-specific transmission cycles in highly endemic regions, (2) a single pool of infection shared by humans and pigs in non-endemic regions. Recently, A. suum has been suggested as an important cause of human ascariasis in endemic areas such as China, where cross-infections and hybridization have also been reported. The main aims of the present study were to investigate the molecular epidemiology of human and pig Ascaris from non-endemic regions and, with reference to existing data, to infer the phylogenetic and phylogeographic relationships among the samples. Methodology 151 Ascaris worms from pigs and humans were characterized using PCR-RFLP on nuclear ITS rDNA. Representative geographical sub-samples were also analysed by sequencing a portion of the mitochondrial cox1 gene, to infer the extent of variability at population level. Sequence data were compared to GenBank sequences from endemic and non-endemic regions. Principal Findings No fixed differences between human and pig Ascaris were evident, with the exception of the Slovak population, which displays significant genetic differentiation. The RFLP analysis confirmed pig as a source of human infection in non-endemic regions and as a corridor for the promulgation of hybrid genotypes. Epidemiology and host-affiliation seem not to be relevant in shaping molecular variance. Phylogenetic and phylogeographical analyses described a complex scenario, involving multiple hosts, sporadic contact between forms and an ancestral taxon referable to A. suum. Conclusions/Significance These results suggest the existence of homogenizing gene flow between the two taxa, which appear to be variants of a single polytypic species. This conclusion has implications on the systematics, transmission and control programs relating to ascariasis. Ascaris lumbricoides, the world's most common human nematode, and A. suum, the pig roundworm, are two of the most important soil-transmitted helminthes of public health and socio-economic concern. However, previously documented similarities at the morphological and genetic level, coupled with evidence for hybridization and gene flow, have clouded the taxonomic distinctiveness of these two nematodes. To date, molecular epidemiological studies have been carried out, mostly in highly endemic regions, where two different transmission cycles have been described. Recently, pigs have been recognized as an important source of human ascariasis in China, opening questions about the zoonotic potential and the efficiency of control programs. Here, samples from non-endemic regions have been analysed using a nuclear marker to identify nematodes to species level plus a mitochondrial marker to investigate the phylogeographic relationships among individuals of the two species from both endemic and non-endemic regions. Results obtained suggested that A. suum and A. lumbricoides may be variants of the same species, with the lack of fixed genetic differences and considerable phylogeographic admixture confirming an extremely close evolutionary relationship among these nematodes. This study highlights the need to further explore the evolutionary affinities of the two taxa to help shed light on the epidemiology of ascariasis.
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Affiliation(s)
- Serena Cavallero
- Department of Public Health and Infectious Diseases, Section of Parasitology, Sapienza University of Rome, Rome, Italy
| | - Viliam Snabel
- Institute of Parasitology, Slovak Academy of Sciences, Kosice, Slovakia
| | - Francesca Pacella
- Department of Public Health and Infectious Diseases, Section of Parasitology, Sapienza University of Rome, Rome, Italy
| | | | - Stefano D'Amelio
- Department of Public Health and Infectious Diseases, Section of Parasitology, Sapienza University of Rome, Rome, Italy
- * E-mail:
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A perfect time to harness advanced molecular technologies to explore the fundamental biology of Toxocara species. Vet Parasitol 2013; 193:353-64. [DOI: 10.1016/j.vetpar.2012.12.031] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Iñiguez AM, Leles D, Jaeger LH, Carvalho-Costa FA, Araújo A. Genetic characterisation and molecular epidemiology of Ascaris spp. from humans and pigs in Brazil. Trans R Soc Trop Med Hyg 2012; 106:604-12. [DOI: 10.1016/j.trstmh.2012.06.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 06/20/2012] [Accepted: 06/20/2012] [Indexed: 10/27/2022] Open
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Awad AM, El-Nahas AF, Abu-Akkada SS. Evaluation of the protective efficacy of the anticoccidial vaccine Coccivac-B in broilers, when challenged with Egyptian field isolates of E. tenella. Parasitol Res 2012; 112:113-21. [PMID: 23001507 DOI: 10.1007/s00436-012-3112-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2012] [Accepted: 08/28/2012] [Indexed: 11/30/2022]
Abstract
The present study was performed to explore the efficacy of the commercial anticoccidial vaccine (Coccivac B®) in broiler chickens using five field strains of Eimeria tenella that were isolated from five provinces in Egypt. This study also analyzed the ITS-1-rDNA sequence of these five strains and its corresponding sequence in the vaccine. In a floor pen experiment, 216 one-day-old commercial broiler chicks were classified into vaccinated and non-vaccinated groups. Each main group was classified into six subgroups. The chicks were challenged on the 28th day of age with 10(4) sporulated oocysts of one of the five field strains of E. tenella. Our results indicated that Coccivac B® produced variable degrees of protection in the birds infected with the five different strains of E. tenella. Aligning the ITS-1 sequences from the five strains with the ITS-1 sequence of E. tenella from the vaccine revealed 96 % sequence similarity with the Kafer El-Sheikh strain, 94 % with the Gharbia strain, 90 % with the Alexandria strain, and 78 % with the Matrouh and Behera strains. While interesting, these similarity values were not useful for predicting the protection conferred by the vaccine against the five field isolates. However, based on the data reported here, we can conclude that Coccivac B® produced variable degrees of protection in the birds infected with the five different strains of E. tenella.
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Affiliation(s)
- Asharaf M Awad
- Department of Avian and Aquatic Diseases, Faculty of Veterinary Medicine, Alexandria University, Edfina, Egypt
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31
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Zhou C, Li M, Yuan K, Deng S, Peng W. Pig Ascaris: An important source of human ascariasis in China. INFECTION GENETICS AND EVOLUTION 2012; 12:1172-7. [DOI: 10.1016/j.meegid.2012.04.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 04/13/2012] [Accepted: 04/17/2012] [Indexed: 10/28/2022]
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32
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Ascaris: Development of selected genotypes in mice. Exp Parasitol 2012; 131:69-74. [DOI: 10.1016/j.exppara.2012.03.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 05/15/2011] [Accepted: 03/08/2012] [Indexed: 11/18/2022]
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Assessing the zoonotic potential ofAscaris suumandTrichuris suis: looking to the future from an analysis of the past. J Helminthol 2012; 86:148-55. [DOI: 10.1017/s0022149x12000193] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AbstractThe two geohelminths,Ascaris lumbricoidesandTrichuris trichiura, infect more than a billion people worldwide but are only reported sporadically in the developed part of the world. In contrast, the closely related speciesA. suumandT. suisin pigs have a truly global distribution, with infected pigs found in most production systems. In areas where pigs and humans live in close proximity or where pig manure is used as fertilizer on vegetables for human consumption, there is a potential risk of cross-infections. We therefore review this relationship betweenAscarisandTrichurisin the human and pig host, with special focus on recent evidence concerning the zoonotic potential of these parasites, and identify some open questions for future research.
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Currier RW, Walton SF, Currie BJ. Scabies in animals and humans: history, evolutionary perspectives, and modern clinical management. Ann N Y Acad Sci 2012; 1230:E50-60. [DOI: 10.1111/j.1749-6632.2011.06364.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ascariasis in people and pigs: New inferences from DNA analysis of worm populations. INFECTION GENETICS AND EVOLUTION 2012; 12:227-35. [DOI: 10.1016/j.meegid.2012.01.012] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 01/12/2012] [Accepted: 01/14/2012] [Indexed: 11/18/2022]
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Leles D, Gardner SL, Reinhard K, Iñiguez A, Araujo A. Are Ascaris lumbricoides and Ascaris suum a single species? Parasit Vectors 2012; 5:42. [PMID: 22348306 PMCID: PMC3293767 DOI: 10.1186/1756-3305-5-42] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Accepted: 02/20/2012] [Indexed: 11/29/2022] Open
Abstract
Since the original description and naming of Ascaris lumbricoides from humans by Linnaeus in 1758 and later of Ascaris suum from pigs by Goeze 1782, these species have been considered to be valid. Four hypotheses relative to the conspecificity or lack thereof (and thus origin of these species) are possible: 1) Ascaris lumbricoides (usually infecting humans) and Ascaris suum (recorded mostly from pigs) are both valid species, with the two species originating via a speciation event from a common ancestor sometime before the domestication of pigs by humans, or 2) Ascaris lumbricoides in humans is derived directly from the species A. suum found in pigs with A. suum then existing as a persistent ancestor after formation of A. lumbricoides, or 3) Ascaris suum is derived directly from A. lumbricoides with the persistent ancestor being A. lumbricoides and A. suum being the newly derived species, and finally, 4) Ascaris lumbricoides and A. suum are the same species, this hypothesis being supported by studies showing both low morphological and low genetic divergence at several genes. We present and discuss paleoparasitological and genetic evidence that complement new data to evaluate the origin and evolution of Ascaris spp. in humans and pigs, and the uniqueness of the species in both hosts. Finally, we conclude that Ascaris lumbricoides and A. suum are a single species and that the name A. lumbricoides Linnaeus 1758 has taxonomic priority; therefore A. suum Goeze 1782 should be considered a synonym of A. lumbricoides.
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Affiliation(s)
- Daniela Leles
- Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, MIP-UFF, Rua Professor Hernani Melo 101, São Domingos, Niterói, 24210-130, RJ, Brazil
| | - Scott L Gardner
- School of Biological Sciences, University of Nebraska- Lincoln, Harold W. Manter Laboratory of Parasitology W 529 Nebraska Hall University of Nebraska-Lincoln Lincoln, Nebraska 68588-0514 USA
| | - Karl Reinhard
- School of Natural Resource Sciences, University of Nebraska at Lincoln, 6940 Van Dorn Street Ste 105, Lincoln, Nebraska 68506, USA
| | - Alena Iñiguez
- Intituto Oswaldo Cruz, Fundação Oswaldo Cruz, Av. Brasil 4365, Manguinhos, Rio de Janeiro, 21045-900, RJ, Brazil
| | - Adauto Araujo
- Escola Nacional de Saúde Pública, Fundação Oswaldo Cruz, Rua Leopoldo Bulhões 1480, Manguinhos, Rio de Janeiro, 21041-210, RJ, Brazil
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Liu GH, Wu CY, Song HQ, Wei SJ, Xu MJ, Lin RQ, Zhao GH, Huang SY, Zhu XQ. Comparative analyses of the complete mitochondrial genomes of Ascaris lumbricoides and Ascaris suum from humans and pigs. Gene 2011; 492:110-6. [PMID: 22075400 DOI: 10.1016/j.gene.2011.10.043] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 10/03/2011] [Accepted: 10/20/2011] [Indexed: 12/12/2022]
Abstract
Ascaris lumbricoides and Ascaris suum are parasitic nematodes living in the small intestine of humans and pigs, and can cause the disease ascariasis. For long, there has been controversy as to whether the two ascaridoid taxa represent the same species due to their significant resemblances in morphology. However, the complete mitochondrial (mt) genome data have been lacking for A. lumbricoides in spite of human and animal health significance and socio-economic impact globally of these parasites. In the present study, we sequenced the complete mt genomes of A. lumbricoides and A. suum (China isolate), which was 14,303 bp and 14,311 bp in size, respectively. The identity of the mt genomes was 98.1% between A. lumbricoides and A. suum (China isolate), and 98.5% between A. suum (China isolate) and A. suum (USA isolate). Both genomes are circular, and consist of 36 genes, including 12 genes for proteins, 2 genes for rRNA and 22 genes for tRNA, which are consistent with that of all other species of ascaridoid studied to date. All genes are transcribed in the same direction and have a nucleotide composition high in A and T (71.7% for A. lumbricoides and 71.8% for A. suum). The AT bias had a significant effect on both the codon usage pattern and amino acid composition of proteins. Phylogenetic analyses of A. lumbricoides and A. suum using concatenated amino acid sequences of 12 protein-coding genes, with three different computational algorithms (Bayesian analysis, maximum likelihood and maximum parsimony) all clustered in a clade with high statistical support, indicating that A. lumbricoides and A. suum was very closely related. These mt genome data and the results provide some additional genetic evidence that A. lumbricoides and A. suum may represent the same species. The mt genome data presented in this study are also useful novel markers for studying the molecular epidemiology and population genetics of Ascaris.
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Affiliation(s)
- Guo-Hua Liu
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China
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Helminth parasites in pigs: New challenges in pig production and current research highlights. Vet Parasitol 2011; 180:72-81. [DOI: 10.1016/j.vetpar.2011.05.029] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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39
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Betson M, Halstead FD, Nejsum P, Imison E, Khamis IS, Sousa-Figueiredo JC, Rollinson D, Stothard JR. A molecular epidemiological investigation of Ascaris on Unguja, Zanzibar using isoenyzme analysis, DNA barcoding and microsatellite DNA profiling. Trans R Soc Trop Med Hyg 2011; 105:370-9. [PMID: 21605883 DOI: 10.1016/j.trstmh.2011.04.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 04/13/2011] [Accepted: 04/13/2011] [Indexed: 11/20/2022] Open
Abstract
Ascariasis is of public health importance on the islands of Zanzibar (Unguja and Pemba). To shed light on the molecular epidemiology of this parasite, 68 Ascaris worms, obtained from 14 individuals in four Ungujan villages, were examined by isoenzyme analysis (ISA), DNA barcoding and microsatellite DNA profiling. ISA revealed genetic variation, which was confirmed by DNA barcoding. Nineteen worms recovered from individuals in Uganda were included for comparison. Sixteen unique DNA barcodes were identified, 15 on Unguja and three in Uganda with two shared between. These two barcodes were found in all four Ungujan villages. Worms from Tumbatu-Jongowe, an isolated village on an islet off Unguja, seemed particularly diverse. Within our barcodes, three exact matches were found with Chinese Ascaris retrieved from pigs, which is perhaps surprising given the present rarity of these animals on Unguja. Microsatellite profiling and population genetic analysis revealed further genetic diversity within our samples although population sub-structuring within Unguja was minor in comparison to that between Unguja and Uganda. As African Ascaris has not been subjected to detailed molecular scrutiny, this new diversity represents an important piece in its evolutionary jigsaw and such population markers are informative in monitoring worm dynamics during ongoing control.
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Affiliation(s)
- Martha Betson
- Wolfson Wellcome Biomedical Laboratories, Department of Zoology, Natural History Museum, Cromwell Road, London, UK
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Zhou C, Li M, Yuan K, Hu N, Peng W. Phylogeography of Ascaris lumbricoides and A. suum from China. Parasitol Res 2011; 109:329-38. [PMID: 21301872 DOI: 10.1007/s00436-011-2260-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 01/18/2011] [Indexed: 10/18/2022]
Abstract
In order to obtain further understanding of genetic structure and evolutionary relationship of Ascaris from humans and pigs, phylogeography study on 12 populations from six endemic regions in China was conducted using mitochondrial DNA markers (cytochrome c oxidase subunit 1 (COX1) and NAD1) and the software programs of DnaSP 5.0, Arlequin 3.0, MEGA 4.0, and NETWORK 4.5.1.6. Results showed that (a) genetic diversity of Ascaris varied with hosts and locations, but no distinct geographical distribution pattern was found, (b) a higher level of genetic diversity and differentiation was found in pig-derived populations in contrast to human-derived ones, and in populations of human-derived Ascaris from the southern regions in comparison to that from the middle and northern locations, but similar geographical difference was not observed within pig-derived populations, (c) historical population expanding was detected from a large part of human-derived Ascaris populations but not in pig-derived Ascaris, (d) a high level of gene flow was detected between human- and pig-derived Ascaris and also among human-derived populations, and (e) network analysis from haplotype of COX1 indicated an ancestral haplotype from human-derived Ascaris. In conclusion, the present study revealed new information on Ascaris on the aspects of genetic diversity, population differentiation and historical demographic patterns, gene flow, phylogenesis reconstruction, and haplotype network, discussed the results with historical demographic migration of humans and domestication of wild boar in China, and raised a different assumption about the evolutionary relationship of the two roundworms. This study should have certain enlightenment for the epidemiology and the evolutionary and taxonomy relationship of Ascaris from humans and pigs.
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Affiliation(s)
- Chunhua Zhou
- Department of Parasitology, College of Basic Medicine, Nanchang University, Xuefu Dadao 999, Nanchang 330031, People's Republic of China
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Abstract
Ascaris lumbricoides and Ascaris suum are widespread parasitic nematodes of humans and pigs respectively. Recent prevalence data suggests that approximately 1.2 billion people are infected. Adult worms exhibit an overdispersed frequency distribution in their hosts and individuals harbouring heavy burdens display associated morbidity. In this review, we describe the parasite, its distribution and measures undertaken to control infection.
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Affiliation(s)
- Christina Dold
- Department of Zoology, School of Natural Science, Trinity College, Dublin 2, Ireland.
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Jex AR, Waeschenbach A, Littlewood DTJ, Hu M, Gasser RB. The mitochondrial genome of Toxocara canis. PLoS Negl Trop Dis 2008; 2:e273. [PMID: 18682828 PMCID: PMC2483351 DOI: 10.1371/journal.pntd.0000273] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Accepted: 07/10/2008] [Indexed: 11/25/2022] Open
Abstract
Toxocara canis (Ascaridida: Nematoda), which parasitizes (at the adult stage) the small intestine of canids, can be transmitted to a range of other mammals, including humans, and can cause the disease toxocariasis. Despite its significance as a pathogen, the genetics, epidemiology and biology of this parasite remain poorly understood. In addition, the zoonotic potential of related species of Toxocara, such as T. cati and T. malaysiensis, is not well known. Mitochondrial DNA is known to provide genetic markers for investigations in these areas, but complete mitochondrial genomic data have been lacking for T. canis and its congeners. In the present study, the mitochondrial genome of T. canis was amplified by long-range polymerase chain reaction (long PCR) and sequenced using a primer-walking strategy. This circular mitochondrial genome was 14162 bp and contained 12 protein-coding, 22 transfer RNA, and 2 ribosomal RNA genes consistent for secementean nematodes, including Ascaris suum and Anisakis simplex (Ascaridida). The mitochondrial genome of T. canis provides genetic markers for studies into the systematics, population genetics and epidemiology of this zoonotic parasite and its congeners. Such markers can now be used in prospecting for cryptic species and for exploring host specificity and zoonotic potential, thus underpinning the prevention and control of toxocariasis in humans and other hosts.
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Affiliation(s)
- Aaron R. Jex
- Department of Veterinary Science, The University of Melbourne, Werribee, Victoria, Australia
| | | | | | - Min Hu
- Department of Veterinary Science, The University of Melbourne, Werribee, Victoria, Australia
| | - Robin B. Gasser
- Department of Veterinary Science, The University of Melbourne, Werribee, Victoria, Australia
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Abstract
In any geographical area, surveys of the prevalence of intestinal helminths are necessary to suggest appropriate control measures. The aim of this study was to determine the prevalence of intestinal helminth infections in children of the Kashmir valley and to identify the risk factors. Stool samples were collected from 2256 children from rural as well as urban areas of the Kashmir valley. The samples were examined by simple smear and zinc sulphate concentration methods. Intensity of the infection was quantified by Stoll's egg-counting technique. Infection by at least one intestinal helminth was found in 71.18% of the sampled population. The prevalence of Ascaris lumbricoides was highest (68.30%), followed by Trichuris trichiura (27.92%), Enterobius vermicularis (12.67%) and Taenia saginata (4.60%). Light (57.1%) to moderate (42.8%) intensity of infection was observed for A. lumbricoides, while the majority of the infected children (92.3%) harboured a light intensity of infection for T. trichiura. The age group, rural or urban residence, type of water source, boiled or unboiled water, type of defecation site, level of personal hygiene and maternal education were associated with helminth infection. Adequate control measures are urgently needed to combat the high prevalence of intestinal helminths and risk factors in the children of Kashmir valley.
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Criscione CD, Anderson JD, Sudimack D, Peng W, Jha B, Williams-Blangero S, Anderson TJC. Disentangling hybridization and host colonization in parasitic roundworms of humans and pigs. Proc Biol Sci 2007; 274:2669-77. [PMID: 17725977 PMCID: PMC2279219 DOI: 10.1098/rspb.2007.0877] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Knowledge of cross-transmission and hybridization between parasites of humans and reservoir hosts is critical for understanding the evolution of the parasite and for implementing control programmes. There is now a consensus that populations of pig and human Ascaris (roundworms) show significant genetic subdivision. However, it is unclear whether this has resulted from a single or multiple host shift(s). Furthermore, previous molecular data have not been sufficient to determine whether sympatric populations of human and pig Ascaris can exchange genes. To disentangle patterns of host colonization and hybridization, we used 23 microsatellite loci to conduct Bayesian clustering analyses of individual worms collected from pigs and humans. We observed strong differentiation between populations which was primarily driven by geography, with secondary differentiation resulting from host affiliation within locations. This pattern is consistent with multiple host colonization events. However, there is low support for the short internal branches of the dendrograms. In part, the relationships among clusters may result from current hybridization among sympatric human and pig roundworms. Indeed, congruence in three Bayesian methods indicated that 4 and 7% of roundworms sampled from Guatemala and China, respectively, were hybrids. These results indicate that there is contemporary cross-transmission between populations of human and pig Ascaris.
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Affiliation(s)
- Charles D Criscione
- Department of Genetics, Southwest Foundation for Biomedical Research, PO Box 760549, San Antonio, TX 78245, USA.
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Criscione CD, Anderson JD, Raby K, Sudimack D, Subedi J, Rai DR, Upadhayay RP, Jha B, Williams-Blangero S, Anderson TJC. Microsatellite markers for the human nematode parasite Ascaris lumbricoides: development and assessment of utility. J Parasitol 2007; 93:704-8. [PMID: 17626368 DOI: 10.1645/ge-1058r.1] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
We describe 35 microsatellite markers from the human parasitic nematode Ascaris lumbricoides. We found 7 sex-linked markers and demonstrate that 26 autosomal loci can be scored reliably. These markers have high genetic variability and provide the tools to address multiple questions concerning the epidemiology, fine-scale genetic structure, host specificity, and mating systems of this parasite.
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Affiliation(s)
- Charles D Criscione
- Department of Genetics, Southwest Foundation for Biomedical Research, P.O. Box 760549, San Antonio, Texas 78245, USA.
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Mallet J, Beltrán M, Neukirchen W, Linares M. Natural hybridization in heliconiine butterflies: the species boundary as a continuum. BMC Evol Biol 2007; 7:28. [PMID: 17319954 PMCID: PMC1821009 DOI: 10.1186/1471-2148-7-28] [Citation(s) in RCA: 178] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2006] [Accepted: 02/23/2007] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND To understand speciation and the maintenance of taxa as separate entities, we need information about natural hybridization and gene flow among species. RESULTS Interspecific hybrids occur regularly in Heliconius and Eueides (Lepidoptera: Nymphalidae) in the wild: 26-29% of the species of Heliconiina are involved, depending on species concept employed. Hybridization is, however, rare on a per-individual basis. For one well-studied case of species hybridizing in parapatric contact (Heliconius erato and H. himera), phenotypically detectable hybrids form around 10% of the population, but for species in sympatry hybrids usually form less than 0.05% of individuals. There is a roughly exponential decline with genetic distance in the numbers of natural hybrids in collections, both between and within species, suggesting a simple "exponential failure law" of compatibility as found in some prokaryotes. CONCLUSION Hybridization between species of Heliconius appears to be a natural phenomenon; there is no evidence that it has been enhanced by recent human habitat disturbance. In some well-studied cases, backcrossing occurs in the field and fertile backcrosses have been verified in insectaries, which indicates that introgression is likely, and recent molecular work shows that alleles at some but not all loci are exchanged between pairs of sympatric, hybridizing species. Molecular clock dating suggests that gene exchange may continue for more than 3 million years after speciation. In addition, one species, H. heurippa, appears to have formed as a result of hybrid speciation. Introgression may often contribute to adaptive evolution as well as sometimes to speciation itself, via hybrid speciation. Geographic races and species that coexist in sympatry therefore form part of a continuum in terms of hybridization rates or probability of gene flow. This finding concurs with the view that processes leading to speciation are continuous, rather than sudden, and that they are the same as those operating within species, rather than requiring special punctuated effects or complete allopatry. Although not qualitatively distinct from geographic races, nor "real" in terms of phylogenetic species concepts or the biological species concept, hybridizing species of Heliconius are stably distinct in sympatry, and remain useful groups for predicting morphological, ecological, behavioural and genetic characteristics.
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Affiliation(s)
- James Mallet
- Galton Laboratory, University College London, Wolfson House, 4 Stephenson Way, London NW1 2HE, UK
- Department of Entomology, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
- Smithsonian Tropical Research Institute, Balboa, Apartado 2072, Panamá
| | - Margarita Beltrán
- Galton Laboratory, University College London, Wolfson House, 4 Stephenson Way, London NW1 2HE, UK
- Smithsonian Tropical Research Institute, Balboa, Apartado 2072, Panamá
| | | | - Mauricio Linares
- Departamento de Ciencias Biológicas, Instituto de Genética, Universidad de los Andes, Carrera 1E No 18A10, Bogotá, Colombia
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Peng W, Yuan K, Hu M, Gasser RB. Recent insights into the epidemiology and genetics of Ascaris in China using molecular tools. Parasitology 2006; 134:325-30. [PMID: 17052373 DOI: 10.1017/s0031182006001521] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Revised: 08/16/2006] [Accepted: 08/17/2006] [Indexed: 11/07/2022]
Abstract
Ascaris is a large parasitic roundworm (nematode) of the small intestine of humans and pigs, which causes the socio-economically important disease, ascariasis. To better understand the relationship of Ascaris between the 2 host species, recent studies in China have focused on investigating the genetics and epidemiology of Ascaris from humans and pigs using a mutation scanning-based approach. Findings provided support for a low level of gene flow between the human and porcine Ascaris populations. Extending the studies of genotypic variability within Ascaris from humans and pigs, experimental infections of mice and pigs with selected genotypes of Ascaris were carried out. Initial results indicate that there is a significant difference in the ability of Ascaris eggs of genotype G1 (derived from human) and G3 (derived from pig) to infect and establish as adults in pigs, supporting the difference in the frequencies of these genotypes in natural Ascaris populations between pigs and humans in China. Taken together, current information supports that there is limited cross-infection of Ascaris between humans and pigs in endemic regions and that pigs are not a significant reservoir of human infection with the adult nematode in such areas.
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Affiliation(s)
- W Peng
- Department of Veterinary Science, The University of Melbourne, 250 Princes Highway, Werribee, Victoria 3030, Australia.
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48
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Islam MK, Miyoshi T, Yamada M, Alim MA, Huang X, Motobu M, Tsuji N. Effect of piperazine (diethylenediamine) on the moulting, proteome expression and pyrophosphatase activity of Ascaris suum lung-stage larvae. Acta Trop 2006; 99:208-17. [PMID: 16987490 DOI: 10.1016/j.actatropica.2006.08.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2006] [Revised: 08/01/2006] [Accepted: 08/03/2006] [Indexed: 11/29/2022]
Abstract
Piperazine (diethylenediamine) is an anthelmintic widely used against animal and bird ascariasis. In this study, we show that treatment with piperazine blocks Ascaris suum larval moulting and development processes and affects larval proteome expression profiles. A. suum lung-stage L3 (LL3) obtained from an infected rabbit's lungs were cultured in RPMI medium in the presence of increasing concentrations of piperazine sulfate (Pzes). Our results showed that Pzes potently inhibited moulting of A. suum LL3 in a dose-dependent manner and that moulting was completely blocked (100%) at 50mM concentrations. We then examined the changes in A. suum LL3 proteome expression patterns following Pzes exposure using two-dimensional (2D) electrophoresis. Pzes exposure inhibited expression of at least 16 major protein spots in unmoulted LL3 out of more than 200 visible protein spots resolved on 2D gels prepared from moulted larvae (i.e., lung-stage L4). Pzes exposure also inhibited expression of 13 immunogenic protein spots in unmoulted LL3. More importantly, Pzes exposure inhibited activity of a moulting-specific enzyme, inorganic pyrophosphatase of A. suum (AsPPase), by 26%. Expression of native AsPPase was also reduced following Pzes exposure as detected by immunoblotting and immunofluorescent staining. Transmission electron microscopy showed that Pzes interfered with growth and ecdysis of the cuticle and caused damage to gut tissues of the larvae. Our results suggest that A. suum LL3 may become a suitable model to screening new-class anthelmintics with antimoulting functions and that A. suum LL3-Pzes may serve as a useful tool for identification of moulting-specific potential proteins in Ascaris roundworms.
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Affiliation(s)
- M Khyrul Islam
- Laboratory of Parasitic Diseases, National Institute of Animal Health, National Agricultural Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan
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Peng W, Yuan K, Hu M, Peng G, Zhou X, Hu N, Gasser RB. Experimental infections of pigs and mice with selected genotypes of Ascaris. Parasitology 2006; 133:651-7. [PMID: 16834792 DOI: 10.1017/s0031182006000643] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2006] [Revised: 05/13/2006] [Accepted: 05/14/2006] [Indexed: 11/06/2022]
Abstract
Extending a previous investigation of the genotypic variability within Ascaris from humans and pigs, experimental infections of mice and pigs with selected genotypes of Ascaris were performed in the present study to explore possible host affiliation. Initial findings indicate that there is a significant difference in the ability of Ascaris eggs of genotype G1 (derived from human) and G3 (derived from pig) to infect and establish as larvae in mice and as adults in pigs, supporting the difference in the frequencies of the genotypes reported previously in natural Ascaris populations in pigs and humans in areas in China endemic for ascariasis.
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Affiliation(s)
- W Peng
- Jiangxi Medical Science Research Institute, Nanchang University, 461 Ba Yi Road, Nanchang, Jiangxi 330006, People's Republic of China.
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50
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Cutter AD, Félix MA, Barrière A, Charlesworth D. Patterns of nucleotide polymorphism distinguish temperate and tropical wild isolates of Caenorhabditis briggsae. Genetics 2006; 173:2021-31. [PMID: 16783011 PMCID: PMC1569728 DOI: 10.1534/genetics.106.058651] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Caenorhabditis briggsae provides a natural comparison species for the model nematode C. elegans, given their similar morphology, life history, and hermaphroditic mode of reproduction. Despite C. briggsae boasting a published genome sequence and establishing Caenorhabditis as a model genus for genetics and development, little is known about genetic variation across the geographic range of this species. In this study, we greatly expand the collection of natural isolates and characterize patterns of nucleotide variation for six loci in 63 strains from three continents. The pattern of polymorphisms reveals differentiation between C. briggsae strains found in temperate localities in the northern hemisphere from those sampled near the Tropic of Cancer, with diversity within the tropical region comparable to what is found for C. elegans in Europe. As in C. elegans, linkage disequilibrium is pervasive, although recombination is evident among some variant sites, indicating that outcrossing has occurred at a low rate in the history of the sample. In contrast to C. elegans, temperate regions harbor extremely little variation, perhaps reflecting colonization and recent expansion of C. briggsae into northern latitudes. We discuss these findings in relation to their implications for selection, demographic history, and the persistence of self-fertilization.
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Affiliation(s)
- Asher D Cutter
- Institute of Evolutionary Biology, University of Edinburgh, UK.
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