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Li H, Chen W, Qi W, Ren Z, Pan X, Shen F, Lu J, Zhai J, Wu Y, Zou J, Xiao L, Feng Y, Yuan D. Molecular characterization of a novel Spiruromorpha species in wild Chinese pangolin by mitogenome sequence analysis. Parasitol Res 2024; 123:137. [PMID: 38376760 DOI: 10.1007/s00436-024-08143-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Accepted: 01/24/2024] [Indexed: 02/21/2024]
Abstract
Pangolins are susceptible to a variety of gastrointestinal nematodes due to their burrowing lifestyle and feeding habits, and few parasitic nematodes have been reported. Here, a Chinese pangolin with old wounds on its leg and tail was rescued from the Heyuan City, Guangdong Province. The cox1 and SSU rRNA of the worms from the intestine of the Chinese pangolin had the highest sequence identity of 89.58% and 97.95% to the species in the infraorder Spiruromorpha. The complete mitogenome of the worm was further assembled by next-generation sequencing, with a size of 13,708 bp and a GC content of 25.6%. The worm mitogenome had the highest sequence identity of 78.56% to that of Spirocerca lupi, sharing the same gene arrangement with S. lupi and some species in other families under Spiruromorpha. However, the mitogenome between the worm and S. lupi showed differences in codon usage of PCGs, sequences of NCR, and tRNA secondary structures. Phylogenetic analysis showed that the worm mitogenome was clustered with S. lupi in the family Thelaziidae to form a separate branch. However, it is still difficult to identify the worm in the family Thelaziidae because the species in the family Thelaziidae are confused, specifically S. lupi and Thelazia callipaeda in the family Thelaziidae were separated and grouped with species from other families. Thus, the parasitic nematode from the Chinese pangolin may be a novel species in Spiruromorpha and closely related to S. lupi. This study enriches the data on gastrointestinal nematodes in the Chinese pangolin.
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Affiliation(s)
- Hongyi Li
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou, 510642, China
| | - Wu Chen
- Guangzhou Zoo & Guangzhou Wildlife Research Center, Guangzhou, 510070, China
| | - Wenmin Qi
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou, 510642, China
| | - Zhengjiu Ren
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou, 510642, China
| | - Xi Pan
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou, 510642, China
| | - Fei Shen
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou, 510642, China
| | - Jinzhi Lu
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou, 510642, China
| | - Junqiong Zhai
- Guangzhou Zoo & Guangzhou Wildlife Research Center, Guangzhou, 510070, China
| | - Yajiang Wu
- Guangzhou Zoo & Guangzhou Wildlife Research Center, Guangzhou, 510070, China
| | - Jiejian Zou
- Guangdong Wildlife Monitoring and Rescue Center, Guangzhou, 510520, China
| | - Lihua Xiao
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou, 510642, China
| | - Yaoyu Feng
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou, 510642, China.
| | - Dongjuan Yuan
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou, 510642, China.
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The Complete Mitogenome of Toxocara vitulorum: Novel In-Sights into the Phylogenetics in Toxocaridae. Animals (Basel) 2022; 12:ani12243546. [PMID: 36552470 PMCID: PMC9774135 DOI: 10.3390/ani12243546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 12/09/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Toxocara vitulorum (Ascaridida: Nematoda) is one of the most common intestinal nematodes of cattle and buffalos and, therefore, represents a serious threat to their populations worldwide. Despite its significance in veterinary health the epidemiology, population genetics, and molecular ecology of this nematode remain poorly understood. The mitogenome can yield a foundation for studying these areas and assist in the surveillance and control of T. vitulorum. Herein, the first whole mitogenome of T. vitulorum was sequenced utilizing Illumina technology and characterized with bioinformatic pipeline analyses. The entire genome of T. vitulorum was 15,045 bp in length and contained 12 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), and two ribosomal RNAs (rRNAs). The gene arrangement (GA) of T. vitulorum was similar to those of other Toxocara species under GA3. The whole genome showed significant levels of AT and GC skew. Comparative mitogenomics including sequence identities, Ka/Ks, and sliding window analysis, indicated a purifying selection of 12 PCGs with cox1 and nad6 having the lowest and highest evolutionary rate, respectively. Whole amino acid sequence-based phylogenetic analysis supported a novel sister-species relationship of T. vitulorum with the congeneric species Toxocara canis, Toxocara cati, and Toxocara malaysiensis in the family Toxocaridae. Further, 12 (PCGs) single gene-based phylogenies suggested that nad4 and nad6 genes shared same topological trees with that of the whole genome, suggesting that these genes were suitable as novel genetic markers for phylogenetic and evolutionary studies of Ascaridida species. This complete mitogenome of T. vitulorum refined phylogenetic relationships in Toxocaridae and provided the resource of markers for population genetics, systematics, and epidemiology of this bovine nematode.
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Han L, Yang Y, Li H, Zhou X, Zhou M, Liu T, Lu Y, Wang Q, Yang S, Shi M, Li X, Du S, Guan C, Zhang Y, Guo W, Wang J, Chai H, Lan T, Liu H, Liu Q, Sun H, Hou Z. Gene rearrangements in the mitochondrial genome of ten ascaris species and phylogenetic implications for Ascaridoidea and Heterakoidea families. Int J Biol Macromol 2022; 221:1394-1403. [PMID: 36116597 DOI: 10.1016/j.ijbiomac.2022.08.021] [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: 06/21/2022] [Revised: 07/21/2022] [Accepted: 08/03/2022] [Indexed: 11/05/2022]
Abstract
The Ascaridoidea family and Heterakoidea family are the most common and typical representative of large parasites. Although our understanding of these parasites' diversity has expanded by analyses of some mitochondrial genes, there is limited information on these species' evolutionary rates. Here we determined ten complete mitogenome sequences of five subfamilies of Ascaridoidea and one subfamily of Heterakoidea. The phylogenetic tree divided the Ascaridoidea into six monophyletic major clades, and the divergence time of Heterakoidea family and Ascaridoidea family can be placed during the early Carboniferous Period (300-360 Mya). The reconstruction of the ancestral state showed that the gene orders of all species in Ascaridoidea were conserved, and the Heterakoidea had obvious genome rearrangement. The conserved blocks between them were divided into five and the main types are tandem-duplication/random loss (TDRL). These results will help to better understand the gene rearrangements and evolutionary position of ascaris species.
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Affiliation(s)
- Lei Han
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China; Laboratory of Vector-Borne Diseases and Pathogens Ecology, Northeast Forestry University, Harbin 150040, China
| | - Yuling Yang
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China
| | - Haimeng Li
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen 518083, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | | | - Mengchao Zhou
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China
| | - Tianlu Liu
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China
| | - Yaxian Lu
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China
| | - Qing Wang
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen 518083, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shangcheng Yang
- College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Minhui Shi
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen 518083, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiuyun Li
- Harbin Northern Forest Zoo, Harbin 150040, China
| | - Shan Du
- Inner Mongolia Agriculture University, Hohhot 010000, China
| | - Chunyu Guan
- Harbin Northern Forest Zoo, Harbin 150040, China
| | - Yong Zhang
- Center for Animal Disease Control and Prevention of Ordos, Inner Mongolia, Ordos 017000, China
| | - Wei Guo
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150040, China
| | - Jiangang Wang
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen 518083, China
| | - Hongliang Chai
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China; Key Laboratory of Wildlife Conservation, China State Forestry Administration, Harbin 150040, China
| | - Tianming Lan
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen 518083, China; BGI Life Science Joint Research Center, Northeast Forestry University, China
| | - Huan Liu
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen 518083, China; BGI Life Science Joint Research Center, Northeast Forestry University, China
| | - Quan Liu
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China.
| | - Heting Sun
- Biological Disaster Control and Prevention Center, National Forestry and Grassland Administration, Shenyang, China.
| | - Zhijun Hou
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China; Key Laboratory of Wildlife Conservation, China State Forestry Administration, Harbin 150040, China.
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Tuli MD, Li H, Li S, Zhai J, Wu Y, Huang W, Feng Y, Chen W, Yuan D. Molecular detection of a novel Ancylostoma sp. by whole mtDNA sequence from pangolin Manis javanica. Parasit Vectors 2022; 15:70. [PMID: 35236404 PMCID: PMC8889679 DOI: 10.1186/s13071-022-05191-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 02/03/2022] [Indexed: 12/05/2022] Open
Abstract
Background Ancylostoma species are hematophagous parasites that cause chronic hemorrhage in various animals and humans. Pangolins, also known as scaly anteaters, are mammals that live in soil environments where they are readily exposed to soil-borne parasitic nematodes. However, only a limited number of helminth species have been identified in this animal host so far. Methods Ancylostoma sp. was isolated from a wild pangolin, and the complete mitochondrial (mt) genome of Ancylostoma sp. was obtained by Illumina sequencing of total genomic DNA. Results The circular complete mt genome that was assembled had a total length of 13,757 bp and comprised 12 protein-coding genes (PCGs), 22 transfer ribosomal RNAs, two ribosomal RNAs (rRNAs), two non-coding regions and one AT-rich region, but lacked the gene coding for ATPase subunit 8 (atp8). The overall AT content of the mt genome of Ancylostoma sp. was 76%, which is similar to that of other nematodes. The PCGs used two start codons (ATT and TTG) and three stop codons (TAA, TAG, and T). The nucleotide identity of the 12 PCGs ranged from 83.1% to 89.7% and had the highest sequence identity with Ancylostoma caninum among species in the Ancylostomatidae family. Also, the pangolin-derived Ancylostoma sp. lacked repeat sequences in the non-coding regions and in the unique sequence of the short non-coding regions, which differentiated it from other Ancylostoma species. In addition, phylogenetic analyses of 18S rRNA and mtDNA sequences revealed that the Ancylostoma sp. was positioned in a separate branch in the subfamily Ancylostomatinae along with other Ancylostoma species. Conclusions The Ancylostoma sp. isolated from a pangolin in this study was identified as a possible new Ancylostoma species. The identification of this Ancylostoma sp. from pangolin enriches our knowledge of the species in the Ancylostomatidae family and provides information that will lead to a better understanding of the taxonomy, diagnostics, and biology of hookworms. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05191-0.
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Affiliation(s)
- Merga Daba Tuli
- Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Hongyi Li
- Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China
| | - Song Li
- Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China
| | - Junqiong Zhai
- Guangzhou Zoo & Guangzhou Wildlife Research Center, Guangzhou, 510070, China
| | - Yajiang Wu
- Guangzhou Zoo & Guangzhou Wildlife Research Center, Guangzhou, 510070, China
| | - Wanyi Huang
- Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China
| | - Yaoyu Feng
- Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Wu Chen
- Guangzhou Zoo & Guangzhou Wildlife Research Center, Guangzhou, 510070, China.
| | - Dongjuan Yuan
- Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China.
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Palevich N, Maclean PH. Sequencing and Reconstructing Helminth Mitochondrial Genomes Directly from Genomic Next-Generation Sequencing Data. Methods Mol Biol 2022; 2369:27-40. [PMID: 34313982 DOI: 10.1007/978-1-0716-1681-9_3] [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] [Indexed: 02/09/2023]
Abstract
We present a detailed method for extraction of high-molecular weight genomic DNA suitable for numerous DNA sequencing applications, and a straightforward in silico approach for reconstructing novel mitochondrial (mt) genomes directly from total genomic DNA extracts derived from next-generation sequencing (NGS) data sets. The in silico post-sequencing pipeline described is fast, accurate, and highly efficient, with modest memory requirements that can be performed using a standard desktop computer. The approach is particularly effective for obtaining mitochondrial genomes for species with little or no mitochondrial sequence information currently available and overcomes many of the limitations of traditional strategies. The described methodologies are also applicable for metagenomics sequencing from mixed or pooled samples containing multiple species and subsequent specific assembly of specific mitochondrial genomes.
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Affiliation(s)
- Nikola Palevich
- AgResearch Limited, Grasslands Research Centre, Palmerston North, New Zealand.
| | - Paul Haydon Maclean
- AgResearch Limited, Grasslands Research Centre, Palmerston North, New Zealand
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Cháves-González LE, Morales-Calvo F, Mora J, Solano-Barquero A, Verocai GG, Rojas A. What lies behind the curtain: Cryptic diversity in helminth parasites of human and veterinary importance. CURRENT RESEARCH IN PARASITOLOGY & VECTOR-BORNE DISEASES 2022; 2:100094. [PMID: 35800064 PMCID: PMC9253710 DOI: 10.1016/j.crpvbd.2022.100094] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 05/28/2022] [Accepted: 06/07/2022] [Indexed: 11/17/2022]
Abstract
Parasite cryptic species are morphologically indistinguishable but genetically distinct organisms, leading to taxa with unclear species boundaries. Speciation mechanisms such as cospeciation, host colonization, taxon pulse, and oscillation may lead to the emergence of cryptic species, influencing host-parasite interactions, parasite ecology, distribution, and biodiversity. The study of cryptic species diversity in helminth parasites of human and veterinary importance has gained relevance, since their distribution may affect clinical and epidemiological features such as pathogenicity, virulence, drug resistance and susceptibility, mortality, and morbidity, ultimately affecting patient management, course, and outcome of treatment. At the same time, the need for recognition of cryptic species diversity has implied a transition from morphological to molecular diagnostic methods, which are becoming more available and accessible in parasitology. Here, we discuss the general approaches for cryptic species delineation and summarize some examples found in nematodes, trematodes and cestodes of medical and veterinary importance, along with the clinical implications of their taxonomic status. Lastly, we highlight the need for the correct interpretation of molecular information, and the correct use of definitions when reporting or describing new cryptic species in parasitology, since molecular and morphological data should be integrated whenever possible. Cryptic diversity has been described in helminths of human and animal importance. Cryptic species are morphologically indistinguishable but genetically distinct organisms. These entities emerge by different evolutionary and speciation mechanisms. Analysis of molecular and morphological data is needed for cryptic species delimitation. Cryptic diversity may affect pathogenicity, virulence and drug resistance of helminths.
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Affiliation(s)
- Luis Enrique Cháves-González
- Laboratory of Helminthology, Centro de Investigación en Enfermedades Tropicales, University of Costa Rica, San José, Costa Rica
| | - Fernando Morales-Calvo
- Laboratory of Helminthology, Centro de Investigación en Enfermedades Tropicales, University of Costa Rica, San José, Costa Rica
| | - Javier Mora
- Laboratory of Helminthology, Centro de Investigación en Enfermedades Tropicales, University of Costa Rica, San José, Costa Rica
| | - Alberto Solano-Barquero
- Laboratory of Helminthology, Centro de Investigación en Enfermedades Tropicales, University of Costa Rica, San José, Costa Rica
| | - Guilherme G. Verocai
- Department of Veterinary Pathobiology, Texas A&M University, College of Veterinary Medicine and Biomedical Sciences, College Station, TX, USA
| | - Alicia Rojas
- Laboratory of Helminthology, Centro de Investigación en Enfermedades Tropicales, University of Costa Rica, San José, Costa Rica
- Corresponding author. Twitter icon
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A new species of Contracaecum (Nematoda: Anisakidae) found parasitizing Nannopterum brasilianus (Suliformes: Phalacrocoracidae) and Hoplias argentinensis (Characiformes: Erythrinidae) in South America: morphological and molecular characterization of larval and adult stages. J Helminthol 2020; 94:e184. [PMID: 32847645 DOI: 10.1017/s0022149x20000644] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Nematode species of the genus Contracaecum Railliet & Henry, 1912 have been reported around the world in many species of fish-eating birds and seals. Here, Contracaecum jorgei n. sp. is morphologically described using light and scanning electron microscopy for adults and fourth-stage larvae (L4) found in the bird Nannopterum brasilianus and third-stage larvae (L3) found in the freshwater fish Hoplias argentinensis, both from the province of Córdoba, Argentina. Additionally, sequences of cytochrome c oxidase subunit II were obtained from these specimens and molecular phylogenetic analysis was used to determine its relationships within the genus. The present species is distinguished from other species by the number and disposition of cephalic papillae; shape and size of the interlabia; length of the spicules; and number and arrangement of papillae in the posterior end of the male. Furthermore, in the molecular analyses, sequences obtained from adult L4 and L3 specimens of C. jorgei n. sp. were similar and grouped, forming an independent lineage, thus confirming it as a distinct species. Thus, morphological characteristics associated with molecular data support the proposal of a new species.
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Xie Y, Li Y, Gu X, Liu Y, Zhou X, Wang L, He R, Peng X, Yang G. Molecular characterization of ascaridoid parasites from captive wild carnivores in China using ribosomal and mitochondrial sequences. Parasit Vectors 2020; 13:382. [PMID: 32727607 PMCID: PMC7391581 DOI: 10.1186/s13071-020-04254-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 07/21/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Despite the public health importance of toxocariasis/toxascariasis, only a few species of these ascaridoid parasites from wild canine and feline carnivores have been studied at the molecular level so far. Poor understanding of diversity, host distribution and the potential (zoonotic) transmission of the ascaridoid species among wild animals negatively affects their surveillance and control in natural settings. In this study, we updated previous knowledge by profiling the genetic diversity and phylogenetic relationships of ascaridoid species among eleven wild canine and feline animals on the basis of a combined analysis of the ribosomal internal transcribed spacer region (ITS) gene and the partial mitochondrial cytochrome c oxidase subunit 2 (cox2) and NADH dehydrogenase subunit 1 (nad1) genes. RESULTS In total, three genetically distinct ascaridoid lineages were determined to be present among these wild carnivores sampled, including Toxocara canis in Alopex lagopus and Vulpes vulpes, Toxocara cati in Felis chaus, Prionailurus bengalensis and Catopuma temmincki and Toxascaris leonina in Canis lupus, Panthera tigris altaica, Panthera tigris amoyensis, Panthera tigris tigris, Panthera leo and Lynx lynx. Furthermore, it was evident that T. leonina lineage split into three well-supported subclades depending on their host species, i.e. wild felids, dogs and wolves and foxes, based on integrated genetic and phylogenetic evidence, supporting that a complex of T. leonina other than one species infecting these hosts. CONCLUSIONS These results provide new molecular insights into classification, phylogenetic relationships and epidemiological importance of ascaridoids from wild canids and felids and also highlight the complex of the taxonomy and genetics of Toxascaris in their wild and domestic carnivorous hosts.
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Affiliation(s)
- Yue Xie
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, China.
| | - Yingxin Li
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, China
| | - Xiaobin Gu
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, China
| | - Yunjian Liu
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, China
| | - Xuan Zhou
- Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Lu Wang
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, China
| | - Ran He
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, China
| | - Xuerong Peng
- Department of Chemistry, College of Life and Basic Science, Sichuan Agricultural University, Chengdu, 611130, China
| | - Guangyou Yang
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, China.
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Rostami A, Ma G, Wang T, Koehler AV, Hofmann A, Chang BCH, Macpherson CN, Gasser RB. Human toxocariasis - A look at a neglected disease through an epidemiological 'prism'. INFECTION GENETICS AND EVOLUTION 2019; 74:104002. [PMID: 31412276 DOI: 10.1016/j.meegid.2019.104002] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 08/07/2019] [Accepted: 08/09/2019] [Indexed: 01/01/2023]
Abstract
Toxocariasis, a disease caused by infection with larvae of Toxocara canis, T. cati and/or congeners, represents clinical syndromes in humans including visceral and ocular larva migrans, neurotoxocariasis and covert/common toxocariasis. It is reported to be one of the most widespread public health and economically important zoonotic parasitic infections that humans share with dogs, wild canids, including foxes, and possibly other mammals. Humans become infected by accidental ingestion of embryonated Toxocara eggs, or larvae from tissues from domestic or wild paratenic hosts. Most infections are asymptomatic, and human disease may go unnoticed, as clinical investigation is often not pursued and/or diagnostic testing not conducted. Sometimes toxocariasis can be associated with complications, such as allergic and/or neurological disorders, possibly including cognitive or developmental delays in children. There is no anti-toxocariasis vaccine, and chemotherapy in humans varies, depending on symptoms and location of larvae, and may include the administration of albendazole or mebendazole, together with anti-inflammatory corticosteroids. Some recent studies indicate that toxocariasis is having an increased, adverse impact on human health in some, particularly underprivileged, tropical and subtropical communities around the world. Although tens of millions of people, especially children, are expected to be exposed to, or infected with Toxocara species, there is limited precise epidemiological data or information on the relationship between seropositivity and disease (toxocariasis) on a global scale. To gain an improved insight into this area, the present article reviews salient clinical aspects of human toxocariasis and the epidemiology of this disease, with particular reference to seroprevalence, and discusses future research and approaches/measures to understand and prevent/control this socioeconomically important, yet neglected zoonosis.
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Affiliation(s)
- Ali Rostami
- Infectious Diseases and Tropical Medicine Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
| | - Guangxu Ma
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, Australia
| | - Tao Wang
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, Australia
| | - Anson V Koehler
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, Australia
| | - Andreas Hofmann
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, Australia
| | - Bill C H Chang
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, Australia
| | - Calum N Macpherson
- School of Graduate Studies, St. George's University, Grenada; School of Veterinary Medicine, St. George's University, Grenada; Windward Islands Research and Education Foundation, Grenada
| | - Robin B Gasser
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, Australia.
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According to mitochondrial DNA evidence, Parascaris equorum and Parascaris univalens may represent the same species. J Helminthol 2018; 93:383-388. [DOI: 10.1017/s0022149x18000330] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AbstractParascarosis is caused mainly by parasitic infections with Parascaris equorum and Parascaris univalens, the most common ascarid nematodes, in the small intestine of equines. Parascarosis often causes severe illness and even death in foals and yearlings. In this study, we obtained the complete sequence of the P. equorum mitochondrial (mt) genome and compared its organization and structure with that of P. equorum Japan isolate (nearly complete), and the complete mtDNA sequences of P. univalens Switzerland and USA isolates. The complete mtDNA genome of P. equorum China isolate is 13,899 base pairs (bp), making it the smallest of the four genomes. All four Parascaris mt genomes are circular, and all genes are transcribed in the same direction. The P. equorum mtDNA genome consists of 12 protein-coding genes, two ribosomal RNA genes, 22 transfer (t) RNA genes and one non-coding region, which is consistent with P. equorum Japan isolate and P. univalens Switzerland isolate but distinct from P. univalens USA isolate, which has 20 tRNA genes. Differences in nucleotide sequences of the four entire mt genomes range from 0.1–0.9%, and differences in total amino acid sequences of protein-coding genes are 0.2–2.1%. Phylogenetic analyses showed that the four Parascaris species clustered in a clade, indicating that P. equorum and P. univalens are very closely related. These mt genome datasets provide genetic evidence that P. equorum and P. univalens may represent the same species, which will be of use in further studies of the taxonomy, systematics and population genetics of ascarids and other nematodes.
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Ma G, Holland CV, Wang T, Hofmann A, Fan CK, Maizels RM, Hotez PJ, Gasser RB. Human toxocariasis. THE LANCET. INFECTIOUS DISEASES 2018; 18:e14-e24. [PMID: 28781085 DOI: 10.1016/s1473-3099(17)30331-6] [Citation(s) in RCA: 249] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 04/21/2017] [Accepted: 05/11/2017] [Indexed: 12/25/2022]
Abstract
Parasitic nematodes of the genus Toxocara are socioeconomically important zoonotic pathogens. These parasites are usually directly transmitted to the human host via the faecal-oral route and can cause toxocariasis and associated complications, including allergic and neurological disorders. Although tens of millions of people are estimated to be exposed to or infected with Toxocara spp, global epidemiological information on the relationship between seropositivity and toxocariasis is limited. Recent findings suggest that the effect of toxocariasis on human health is increasing in some countries. Here we review the salient background on Toxocara and biology, summarise key aspects of the pathogenesis, diagnosis, and treatment of toxocariasis, describe what is known about its geographic distribution and prevalence, and make some recommendations for future research towards the prevention and control of this important disease.
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Affiliation(s)
- Guangxu Ma
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, VIC, Australia
| | - Celia V Holland
- Department of Zoology, School of Natural Sciences, Trinity College, Dublin, Ireland
| | - Tao Wang
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, VIC, Australia
| | - Andreas Hofmann
- Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD, Australia
| | - Chia-Kwung Fan
- Department of Molecular Parasitology and Tropical Diseases, School of Medicine & Research Center of International Tropical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Rick M Maizels
- Wellcome Centre for Molecular Parasitology, Institute for Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - Peter J Hotez
- Texas Children's Hospital Center for Vaccine Development, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA; Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA; Department of Molecular Virology & Microbiology, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Robin B Gasser
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, VIC, Australia.
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Abstract
Ancylostoma tubaeforme may infect canids, felids and humans, and pose a potential risk to public health. Polymerase chain reaction (PCR) techniques were used to amplify the complete mitochondrial (mt) genome sequence of A. tubaeforme from cats and to analyse its sequence characteristics after molecular identification based on the internal transcribed spacer ITS1+ sequence. The results show that the complete mt genome sequence (GenBank accession number KY070315) of A. tubaeforme from cats was 13,730 bp in length, including 12 protein-coding genes, 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes, two non-coding regions and an AT-rich region. The nucleotide content of A and T was 77.93%, biased toward A and T. Twelve protein-coding genes used ATT, TTG and GTG as initiation codons, and TAA, TAG, TA and T as termination codons. The length of the 22 tRNA genes ranged from 52 to 62 bp, their predicted secondary structures were D loops and V loops. The lengths of the two rRNAs were 958 and 697 bp. Phylogenetic analyses showed that A. tubaeforme from cats was in the lineage of Ancylostoma, having a close phylogenetic relationship with A. caninum. This study reports for the first time the mt genome of A. tubaeforme from cats in China, which could enhance the mt genome database of Ancylostomatidae nematodes, and it offers the scientific basis for further studies in the genetic diversity of hookworms among different hosts.
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He X, Lv MN, Liu GH, Lin RQ. Genetic analysis of Toxocara cati (Nematoda: Ascarididae) from Guangdong province, subtropical China. Mitochondrial DNA A DNA Mapp Seq Anal 2017; 29:132-135. [PMID: 28141958 DOI: 10.1080/24701394.2016.1258404] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Toxocara cati (cat roundworm) is a common parasitic nematode that infects humans and other hosts, causing toxocariasis. Although its significance as a pathogen, the epidemiology, genetics and biology of T. cati remain poorly understand in China. In the present study, genetic variation in mitochondrial (mt) cytochrome c oxidase subunit 1 (cox1) gene and internal transcribed spacer (ITS) of rDNA region among T. cati in Guangdong province, subtropical China was examined. A portion of the cox1 (pcox1) and the complete ITS (ITS1 + 5.8S rDNA + ITS2) were amplified separately from individual worms by polymerase chain reaction (PCR) and amplicons were then subjected to sequencing from both directions. The length of the sequences of pcox1, ITS-1, and ITS-2 were 308 bp, 462 bp, and 335 bp, respectively. The intra-specific sequence variations within T. cati were 0-3.6% for pcox1, 0-2.4% for ITS-1, and 0-2.7% for ITS-2. However, the inter-specific sequence differences were significantly higher, being 8.6%, 10.7%, and 11.3% for pcox1, ITS-1, and ITS-2, respectively. Phylogenetic analyses based on the pcox1 sequences indicated that all the isolates in Guangdong province were in genus Toxocara, which confirmed that these parasites represent T. cati. The molecular approach employed provides a powerful tool for elucidating the epidemiology, genetics, and biology of zoonotic T. cati in China and elsewhere.
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Affiliation(s)
- Xi He
- a College of Veterinary Medicine , South China Agricultural University , Guangzhou , Guangdong Province , PR China.,b Key Laboratory of Zoonosis Prevention and Control of Guangdong Province , Guangzhou , Guangdong Province , PR China
| | - Meng-Na Lv
- a College of Veterinary Medicine , South China Agricultural University , Guangzhou , Guangdong Province , PR China.,b Key Laboratory of Zoonosis Prevention and Control of Guangdong Province , Guangzhou , Guangdong Province , PR China
| | - Guo-Hua Liu
- c College of Veterinary Medicine , Hunan Agricultural University , Changsha , Hunan Province , PR China
| | - Rui-Qing Lin
- a College of Veterinary Medicine , South China Agricultural University , Guangzhou , Guangdong Province , PR China.,b Key Laboratory of Zoonosis Prevention and Control of Guangdong Province , Guangzhou , Guangdong Province , PR China
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Sun MM, Liu GH, Ando K, Woo HC, Ma J, Sohn WM, Sugiyama H, Zhu XQ. Complete mitochondrial genomes of Gnathostoma nipponicum and Gnathostoma sp., and their comparison with other Gnathostoma species. INFECTION GENETICS AND EVOLUTION 2016; 48:109-115. [PMID: 28025097 DOI: 10.1016/j.meegid.2016.12.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Revised: 12/12/2016] [Accepted: 12/21/2016] [Indexed: 11/17/2022]
Abstract
Gnathostomiasis is a foodborne zoonotic parasitosis caused by Gnathostoma nematodes. It has caused significant public problems worldwide, but its molecular biology is limited. The purpose of this study was to decode the complete mitochondrial (mt) genomes of Gnathostoma nipponicum and Gnathostoma sp., and compare their mt sequences with other Gnathostoma species. The complete mt genome sequences were amplified by long-range PCR and determined by subsequent primer walking. The complete mt genomes of G. nipponicum and Gnathostoma sp. were 14,093bp and 14,391bp, respectively. Both of the two mt genomes contain 12 protein-coding genes (PCGs), 2 ribosomal RNA genes and 22 transfer RNA genes. The gene order and transcription direction are the same as G. spinigerum and G. doloresi. The sequence difference across the entire mt genomes varied from 14.4% to 18.2% between G. nipponicum, Gnathostoma sp., G. spinigerum and G. doloresi of Japan and China isolates. Phylogenetic analyses by Bayesian inference (BI) using concatenated amino acid sequences of 12 PCGs showed that G. nipponicum and Gnathostoma sp. are two distinctive species of Gnathostoma, and G. nipponicum are more closely related to Gnathostoma sp. than to G. spinigerum. The mtDNA datasets provide abundant resources of novel markers, which can be used for the studies of molecular epidemiology and diagnosis of Gnathostoma spp.
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Affiliation(s)
- Miao-Miao Sun
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China; College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui Province 230036, PR China
| | - Guo-Hua Liu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China; College of Veterinary Medicine, Hunan Agricultural University, Changsha, Hunan Province 410128, PR China.
| | - Katsuhiko Ando
- Department of Medical Zoology, Mie University School of Medicine, Mie 514-8507, Japan
| | - Ho-Choon Woo
- Department of Veterinary Parasitology, Jeju National University College of Veterinary Medicine, Jeju 690-756, Republic of Korea
| | - Jun Ma
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China
| | - Woon-Mok Sohn
- Department Parasitology and Tropical Medicine, Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju 52727, Republic of Korea
| | - Hiromu Sugiyama
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo 162-8640, Japan
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China; College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui Province 230036, PR China; College of Veterinary Medicine, Hunan Agricultural University, Changsha, Hunan Province 410128, PR China.
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Liu GH, Nadler SA, Liu SS, Podolska M, D'Amelio S, Shao R, Gasser RB, Zhu XQ. Mitochondrial Phylogenomics yields Strongly Supported Hypotheses for Ascaridomorph Nematodes. Sci Rep 2016; 6:39248. [PMID: 27982084 PMCID: PMC5159812 DOI: 10.1038/srep39248] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 11/10/2016] [Indexed: 12/03/2022] Open
Abstract
Ascaridomorph nematodes threaten the health of humans and other animals worldwide. Despite their medical, veterinary and economic importance, the identification of species lineages and establishing their phylogenetic relationships have proved difficult in some cases. Many working hypotheses regarding the phylogeny of ascaridomorphs have been based on single-locus data, most typically nuclear ribosomal RNA. Such single-locus hypotheses lack independent corroboration, and for nuclear rRNA typically lack resolution for deep relationships. As an alternative approach, we analyzed the mitochondrial (mt) genomes of anisakids (~14 kb) from different fish hosts in multiple countries, in combination with those of other ascaridomorphs available in the GenBank database. The circular mt genomes range from 13,948-14,019 bp in size and encode 12 protein-coding genes, 2 ribosomal RNAs and 22 transfer RNA genes. Our analysis showed that the Pseudoterranova decipiens complex consists of at least six cryptic species. In contrast, the hypothesis that Contracaecum ogmorhini represents a complex of cryptic species is not supported by mt genome data. Our analysis recovered several fundamental and uncontroversial ascaridomorph clades, including the monophyly of superfamilies and families, except for Ascaridiidae, which was consistent with the results based on nuclear rRNA analysis. In conclusion, mt genome analysis provided new insights into the phylogeny and taxonomy of ascaridomorph nematodes.
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Affiliation(s)
- Guo-Hua Liu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, P. R. China.,College of Veterinary Medicine, Hunan Agricultural University, Changsha, Hunan Province 410128, P. R. China
| | - Steven A Nadler
- Department of Entomology and Nematology, University of California, Davis, CA 95616, USA
| | - Shan-Shan Liu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, P. R. China
| | - Magdalena Podolska
- National Marine Fisheries Research Institute, Kollataja 1, 81-332 Gdynia, Poland
| | - Stefano D'Amelio
- Department of Public Health and Infectious Diseases, Section of Parasitology, Sapienza University of Rome, Rome, Italy
| | - Renfu Shao
- Genecology Research Centre, University of the Sunshine Coast, Queensland 4558, Australia
| | - Robin B Gasser
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, P. R. China.,College of Veterinary Medicine, Hunan Agricultural University, Changsha, Hunan Province 410128, P. R. China
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16
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Yang S, Feng X, Jiao Z, Lu D, Duan M, Wang G. The complete mitochondrial genome of Caenorhabditis remanei (Rhabditida: Rhabditoidae), in comparison with four other Caenorhabditis species. GENE REPORTS 2016. [DOI: 10.1016/j.genrep.2016.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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17
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Sun MM, Ma J, Sugiyama H, Ando K, Li WW, Xu QM, Liu GH, Zhu XQ. The complete mitochondrial genomes of Gnathostoma doloresi from China and Japan. Parasitol Res 2016; 115:4013-20. [PMID: 27301404 DOI: 10.1007/s00436-016-5171-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 06/07/2016] [Indexed: 11/29/2022]
Abstract
Gnathostoma doloresi is one of the neglected pathogens causing gnathostomiasis. Although this zoonotic parasite leads to significant socioeconomic concerns globally, little is known of its genetics and systematics. In the present study, we sequenced and characterized the complete mitochondrial (mt) genomes of G. doloresi isolates from China and Japan. The lengths of the mt genomes of the G. doloresi China and Japan isolates are 13,809 and 13,812 bp, respectively. Both mt genomes encode 36 genes, including 12 protein-coding genes (PCGs), 2 ribosomal RNA genes, and 22 transfer RNA genes. The gene order, transcription direction, and genome content are identical with its congener G. spinigerum. Phylogenetic analyses based on concatenated amino acid sequences of 12 PCGs by Bayesian inference (BI) indicated that G. doloresi are closely related to G. spinigerum. Our data provide an invaluable resource for studying the molecular epidemiology, phylogenetics, and population genetics of Gnathostoma spp. and should have implications for further studies of the diagnosis, prevention, and control of gnathostomiasis in humans and animals.
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Affiliation(s)
- Miao-Miao Sun
- College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui Province, 230036, China.,State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, 730046, China
| | - Jun Ma
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, 730046, China
| | - Hiromu Sugiyama
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan
| | - Katsuhiko Ando
- Department of Medical Zoology, Mie University School of Medicine, Mie, 514-8507, Japan
| | - Wen-Wen Li
- Department of Animal Experiment Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, 510080, China
| | - Qian-Ming Xu
- College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui Province, 230036, China
| | - Guo-Hua Liu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, 730046, China.
| | - Xing-Quan Zhu
- College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui Province, 230036, China. .,State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, 730046, China.
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18
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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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Le TH, Anh NTL, Nguyen KT, Nguyen NTB, Thuy DTT, Gasser RB. Toxocara malaysiensis infection in domestic cats in Vietnam--An emerging zoonotic issue? INFECTION GENETICS AND EVOLUTION 2015; 37:94-8. [PMID: 26584512 DOI: 10.1016/j.meegid.2015.11.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 11/05/2015] [Accepted: 11/12/2015] [Indexed: 11/28/2022]
Abstract
Toxocara canis of canids is a parasitic nematode (ascaridoid) that infects humans and other hosts, causing different forms of toxocariasis. This species of Toxocara appears to be the most important cause of human disease, likely followed by Toxocara cati from felids. Although some studies from Malaysia and China have shown that cats can harbor another congener, T. malaysiensis, no information is available about this parasite for other countries. Moreover, the zoonotic potential of this parasite is unknown at this point. In the present study, we conducted the first investigation of domestic dogs and cats for Toxocara in Vietnam using molecular tools. Toxocara malaysiensis was identified as a common ascaridoid of domestic cats (in the absence of T. cati), and T. canis was commonly found in dogs. Together with findings from previous studies, the present results emphasize the need to explore the significance and zoonotic potential of T. malaysiensis in Vietnam and other countries where this parasite is endemic and prevalent in cats.
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Affiliation(s)
- Thanh Hoa Le
- Institute of Biotechnology, Vietnam Academy of Science and Technology, 18. Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam.
| | - Nguyen Thi Lan Anh
- Department of Parasitology, National Institute of Veterinary Research, 86 Truong Chinh, Hanoi, Vietnam
| | - Khue Thi Nguyen
- Institute of Biotechnology, Vietnam Academy of Science and Technology, 18. Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam
| | - Nga Thi Bich Nguyen
- Institute of Biotechnology, Vietnam Academy of Science and Technology, 18. Hoang Quoc Viet Rd, Cau Giay, Hanoi, Vietnam
| | - Do Thi Thu Thuy
- Department of Parasitology, National Institute of Veterinary Research, 86 Truong Chinh, Hanoi, Vietnam
| | - Robin B Gasser
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Victoria, Australia
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20
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Borges JN, Santos HLC, Brandão ML, dos Santos EGN, de Miranda DF, Balthazar DDA, Luque JL, Santos CP. Molecular and morphological characterization of Contracaecum pelagicum (Nematoda) parasitizing Spheniscus magellanicus (Chordata) from Brazilian waters. ACTA ACUST UNITED AC 2015; 23:74-9. [PMID: 24728364 DOI: 10.1590/s1984-29612014010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 02/05/2014] [Indexed: 11/22/2022]
Abstract
Three new sequences of Mitochondrial cytochrome c-oxidase subunit 2 (mtDNA cox-2) from C. pelagicum parasite of Spheniscus magellanicus, the Magelanicus penguin, were determined from Brazilian waters. The sequences presented 99 and 98% of similarity with C. pelagicum sequences from Argentina, deposited on GenBank for the same genetic region and with a strong statistical support inferred from the phylogenetic tree. The morphological and ultrastructural studies that were carried out confirmed the genetic analysis.
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Affiliation(s)
- Juliana Novo Borges
- Laboratório de Avaliação e Promoção da Saúde Ambiental ? LAPSA, Instituto Oswaldo Cruz ? IOC, Rio de Janeiro, RJ, Brasil
| | - Helena Lúcia Carneiro Santos
- Laboratório de Avaliação e Promoção da Saúde Ambiental ? LAPSA, Instituto Oswaldo Cruz ? IOC, Rio de Janeiro, RJ, Brasil
| | - Martha Lima Brandão
- Curso de Pós-graduação em Parasitologia Veterinária, Universidade Federal Rural do Rio de Janeiro ? UFRRJ, Seropédica, RJ, Brasil
| | | | - Daniele Ferreira de Miranda
- Laboratório de Avaliação e Promoção da Saúde Ambiental ? LAPSA, Instituto Oswaldo Cruz ? IOC, Rio de Janeiro, RJ, Brasil
| | | | - José Luis Luque
- Departamento de Parasitologia Animal, Universidade Federal Rural do Rio de Janeiro ? UFRRJ, Seropédica, RJ, Brasil
| | - Cláudia Portes Santos
- Laboratório de Avaliação e Promoção da Saúde Ambiental ? LAPSA, Instituto Oswaldo Cruz ? IOC, Rio de Janeiro, RJ, Brasil
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21
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Yang SS, Li S, Wang GX. The complete mitochondrial genome of Caenorhabditis tropicalis n. sp. (Rhabditida: Rhabditidae). Mitochondrial DNA A DNA Mapp Seq Anal 2014; 27:1763-4. [PMID: 25259460 DOI: 10.3109/19401736.2014.963801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In order to further study the characteristic of Caenorhabditis, the complete mitochondrial genome (mitogenome) of a modal nematode species Caenorhabditis tropicalis n. sp. (previous species name: C. sp. 11) was determined. The results showed that the mitogenome was 13,874 bp in length, which contained 12 protein-coding genes (PCGs), 2 ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), an AT-rich region and 2 non-coding regions (NCR). The base composition of the heavy strand was 28.12% A, 47.57% T, 15.53% G, and 8.78% C. Furthermore, it is more significant that this mitogenome has two unique features: One is the AT-rich region which had 4 runs of 12 AT dinucleotides and 4 copies of directly repeated sequence (47 bp) within a pair of inverted repeat sequence (13 bp), and the other is that the NCR (130 bp) between tRNA(Arg) and tRNA(Gln) of 4 small stem-loop which was described at the first time. This paper firstly expounded the the complete mitogenome of C. tropicalis n. sp. So it can enrich the molecular resource and facilitate the further research of the population genetics and systematics for Caenorhabditis.
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Affiliation(s)
- Shuang-Shuang Yang
- a Hubei Key Laboratory of Genetic Regulation and Integrative Biology , College of Life Sciences, Central China Normal University , Wuhan , China
| | - Shan Li
- a Hubei Key Laboratory of Genetic Regulation and Integrative Biology , College of Life Sciences, Central China Normal University , Wuhan , China
| | - Guo-Xiu Wang
- a Hubei Key Laboratory of Genetic Regulation and Integrative Biology , College of Life Sciences, Central China Normal University , Wuhan , China
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22
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Jabbar A, Littlewood DTJ, Mohandas N, Briscoe AG, Foster PG, Müller F, von Samson-Himmelstjerna G, Jex AR, Gasser RB. The mitochondrial genome of Parascaris univalens--implications for a "forgotten" parasite. Parasit Vectors 2014; 7:428. [PMID: 25190631 PMCID: PMC4262126 DOI: 10.1186/1756-3305-7-428] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 09/01/2014] [Indexed: 11/12/2022] Open
Abstract
Background Parascaris univalens is an ascaridoid nematode of equids. Little is known about its epidemiology and population genetics in domestic and wild horse populations. PCR-based methods are suited to support studies in these areas, provided that reliable genetic markers are used. Recent studies have shown that mitochondrial (mt) genomic markers are applicable in such methods, but no such markers have been defined for P. univalens. Methods Mt genome regions were amplified from total genomic DNA isolated from P. univalens eggs by long-PCR and sequenced using Illumina technology. The mt genome was assembled and annotated using an established bioinformatic pipeline. Amino acid sequences inferred from all protein-encoding genes of the mt genomes were compared with those from other ascaridoid nematodes, and concatenated sequences were subjected to phylogenetic analysis by Bayesian inference. Results The circular mt genome was 13,920 bp in length and contained two ribosomal RNA, 12 protein-coding and 22 transfer RNA genes, consistent with those of other ascaridoids. Phylogenetic analysis of the concatenated amino acid sequence data for the 12 mt proteins showed that P. univalens was most closely related to Ascaris lumbricoides and A. suum, to the exclusion of other ascaridoids. Conclusions This mt genome representing P. univalens now provides a rich source of genetic markers for future studies of the genetics and epidemiology of this parasite and its congener, P. equorum. This focus is significant, given that there is no published information on the specific prevalence and distribution of P. univalens infection in domestic and wild horse populations. Electronic supplementary material The online version of this article (doi:10.1186/1756-3305-7-428) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Abdul Jabbar
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, Victoria, Australia.
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23
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Lee D, Choe S, Park H, Jeon HK, Chai JY, Sohn WM, Yong TS, Min DY, Rim HJ, Eom KS. Complete mitochondrial genome of Haplorchis taichui and comparative analysis with other trematodes. THE KOREAN JOURNAL OF PARASITOLOGY 2013; 51:719-26. [PMID: 24516279 PMCID: PMC3916463 DOI: 10.3347/kjp.2013.51.6.719] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 10/02/2013] [Accepted: 10/11/2013] [Indexed: 11/23/2022]
Abstract
Mitochondrial genomes have been extensively studied for phylogenetic purposes and to investigate intra- and interspecific genetic variations. In recent years, numerous groups have undertaken sequencing of platyhelminth mitochondrial genomes. Haplorchis taichui (family Heterophyidae) is a trematode that infects humans and animals mainly in Asia, including the Mekong River basin. We sequenced and determined the organization of the complete mitochondrial genome of H. taichui. The mitochondrial genome is 15,130 bp long, containing 12 protein-coding genes, 2 ribosomal RNAs (rRNAs, a small and a large subunit), and 22 transfer RNAs (tRNAs). Like other trematodes, it does not encode the atp8 gene. All genes are transcribed from the same strand. The ATG initiation codon is used for 9 protein-coding genes, and GTG for the remaining 3 (nad1, nad4, and nad5). The mitochondrial genome of H. taichui has a single long non-coding region between trnE and trnG. H. taichui has evolved as being more closely related to Opisthorchiidae than other trematode groups with maximal support in the phylogenetic analysis. Our results could provide a resource for the comparative mitochondrial genome analysis of trematodes, and may yield genetic markers for molecular epidemiological investigations into intestinal flukes.
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Affiliation(s)
- Dongmin Lee
- Department of Parasitology, Medical Research Institute and Parasite Resource Bank, Chungbuk National University School of Medicine, Cheongju 361-763, Korea
| | - Seongjun Choe
- Department of Parasitology, Medical Research Institute and Parasite Resource Bank, Chungbuk National University School of Medicine, Cheongju 361-763, Korea
| | - Hansol Park
- Department of Parasitology, Medical Research Institute and Parasite Resource Bank, Chungbuk National University School of Medicine, Cheongju 361-763, Korea
| | - Hyeong-Kyu Jeon
- Department of Parasitology, Medical Research Institute and Parasite Resource Bank, Chungbuk National University School of Medicine, Cheongju 361-763, Korea
| | - Jong-Yil Chai
- Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine, Seoul 110-799, Korea
| | - Woon-Mok Sohn
- Department of Parasitology and Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju 660-70-51, Korea
| | - Tai-Soon Yong
- Department of Environmental Medical Biology, Institute of Tropical Medicine and Arthropods of Medical Importance Resource Bank, Yonsei University College of Medicine, Seoul 120-752, Korea
| | - Duk-Young Min
- Department of Immunology and Microbiology, Eulji University School of Medicine, Daejeon 301-746, Korea
| | - Han-Jong Rim
- Department of Parasitology, Korea University College of Medicine, Seoul 136-705, Korea
| | - Keeseon S Eom
- Department of Parasitology, Medical Research Institute and Parasite Resource Bank, Chungbuk National University School of Medicine, Cheongju 361-763, Korea
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Xie Y, Niu L, Zhao B, Wang Q, Nong X, Chen L, Zhou X, Gu X, Wang S, Peng X, Yang G. Complete mitochondrial genomes of chimpanzee- and gibbon-derived Ascaris isolated from a zoological garden in southwest China. PLoS One 2013; 8:e82795. [PMID: 24358225 PMCID: PMC3866200 DOI: 10.1371/journal.pone.0082795] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 10/28/2013] [Indexed: 01/12/2023] Open
Abstract
Roundworms (Ascaridida: Nematoda), one of the most common soil-transmitted helminths (STHs), can cause ascariasis in various hosts worldwide, ranging from wild to domestic animals and humans. Despite the veterinary and health importance of the Ascaridida species, little or no attention has been paid to roundworms infecting wild animals including non-human primates due to the current taxon sampling and survey bias in this order. Importantly, there has been considerable controversy over the years as to whether Ascaris species infecting non-human primates are the same as or distinct from Ascaris lumbricoides infecting humans. Herein, we first characterized the complete mitochondrial genomes of two representative Ascaris isolates derived from two non-human primates, namely, chimpanzees (Pan troglodytes) and gibbons (Hylobates hoolock), in a zoological garden of southwest China and compared them with those of A. lumbricoides and the congeneric Ascaris suum as well as other related species in the same order, and then used comparative mitogenomics, genome-wide nucleotide sequence identity analysis, and phylogeny to determine whether the parasites from chimpanzees and gibbons represent a single species and share genetic similarity with A. lumbricoides. Taken together, our results yielded strong statistical support for the hypothesis that the chimpanzee- and gibbon-derived Ascaris represent a single species that is genetically similar to A. lumbricoides, consistent with the results of previous morphological and molecular studies. Our finding should enhance public alertness to roundworms originating from chimpanzees and gibbons and the mtDNA data presented here also serves to enrich the resource of markers that can be used in molecular diagnostic, systematic, population genetic, and evolutionary biological studies of parasitic nematodes from either wild or domestic hosts.
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Affiliation(s)
- Yue Xie
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Ya’an, Sichuan, China
| | - Lili Niu
- Veterinary Hospital, Chengdu Zoological Garden, Chengdu, Sichuan, China
| | - Bo Zhao
- Veterinary Hospital, Chengdu Zoological Garden, Chengdu, Sichuan, China
| | - Qiang Wang
- Veterinary Hospital, Chengdu Zoological Garden, Chengdu, Sichuan, China
| | - Xiang Nong
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Ya’an, Sichuan, China
| | - Lin Chen
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Ya’an, Sichuan, China
| | - Xuan Zhou
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Ya’an, Sichuan, China
| | - Xiaobin Gu
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Ya’an, Sichuan, China
| | - Shuxian Wang
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Ya’an, Sichuan, China
| | - Xuerong Peng
- Department of Chemistry, College of Life and Basic Science, Sichuan Agricultural University, Ya’an, Sichuan, China
| | - Guangyou Yang
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Ya’an, Sichuan, China
- * E-mail:
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Mohandas N, Jabbar A, Podolska M, Zhu XQ, Littlewood DTJ, Jex AR, Gasser RB. Mitochondrial genomes of Anisakis simplex and Contracaecum osculatum (sensu stricto)--comparisons with selected nematodes. INFECTION GENETICS AND EVOLUTION 2013; 21:452-62. [PMID: 24211683 DOI: 10.1016/j.meegid.2013.10.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 09/26/2013] [Accepted: 10/28/2013] [Indexed: 11/24/2022]
Abstract
Anisakid nematodes parasitize mainly fish, marine mammals and/or fish-eating birds, and can be transmitted to a range of fish-eating mammals, including humans, where they can cause gastrointestinal disease linked to larval infection or allergic responses. In spite of the animal and human health significance of these parasites, there are still gaps in our understanding of the systematics, biology, epidemiology and ecology of anisakids. Mitochondrial (mt) DNA provides useful genetic markers for investigations in these areas, but complete mt genomic data have been lacking for most anisakids. In the present study, the mt genomes of Anisakis simplex sensu stricto and Contracaecum osculatum sensu stricto were amplified from genomic DNA by long-range polymerase chain reaction and sequenced using 454 technology. The circular mt genomes of these species were 13,926 and 13,823 bp, respectively, and each of them contained 12 protein-coding, 22 transfer RNA, and 2 ribosomal RNA genes consistent for members of the Ascaridida, Oxyurida, Spirurida, Rhabditida and Strongylida. These mt genomes provide a stepping-stone for future comparative analyses of a range of anisakids and a basis for reinvestigating their genetic relationships. In addition, these markers might be used in prospecting for cryptic species and exploring host affiliations.
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Affiliation(s)
- Namitha Mohandas
- Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Abdul Jabbar
- Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Magdalena Podolska
- National Marine Fisheries Research Institute (NMFRI), Kollataja 1, 81-332 Gdynia, Poland
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu 730046, China
| | | | - Aaron R Jex
- Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Robin B Gasser
- Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria 3010, Australia.
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The epidemiology and public health importance of toxocariasis: A zoonosis of global importance. Int J Parasitol 2013; 43:999-1008. [DOI: 10.1016/j.ijpara.2013.07.004] [Citation(s) in RCA: 264] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 07/16/2013] [Accepted: 07/18/2013] [Indexed: 11/21/2022]
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Hahn C, Bachmann L, Chevreux B. Reconstructing mitochondrial genomes directly from genomic next-generation sequencing reads--a baiting and iterative mapping approach. Nucleic Acids Res 2013; 41:e129. [PMID: 23661685 PMCID: PMC3711436 DOI: 10.1093/nar/gkt371] [Citation(s) in RCA: 1427] [Impact Index Per Article: 129.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We present an in silico approach for the reconstruction of complete mitochondrial genomes of non-model organisms directly from next-generation sequencing (NGS) data—mitochondrial baiting and iterative mapping (MITObim). The method is straightforward even if only (i) distantly related mitochondrial genomes or (ii) mitochondrial barcode sequences are available as starting-reference sequences or seeds, respectively. We demonstrate the efficiency of the approach in case studies using real NGS data sets of the two monogenean ectoparasites species Gyrodactylus thymalli and Gyrodactylus derjavinoides including their respective teleost hosts European grayling (Thymallus thymallus) and Rainbow trout (Oncorhynchus mykiss). MITObim appeared superior to existing tools in terms of accuracy, runtime and memory requirements and fully automatically recovered mitochondrial genomes exceeding 99.5% accuracy from total genomic DNA derived NGS data sets in <24 h using a standard desktop computer. The approach overcomes the limitations of traditional strategies for obtaining mitochondrial genomes for species with little or no mitochondrial sequence information at hand and represents a fast and highly efficient in silico alternative to laborious conventional strategies relying on initial long-range PCR. We furthermore demonstrate the applicability of MITObim for metagenomic/pooled data sets using simulated data. MITObim is an easy to use tool even for biologists with modest bioinformatics experience. The software is made available as open source pipeline under the MIT license at https://github.com/chrishah/MITObim.
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Affiliation(s)
- Christoph Hahn
- Natural History Museum, University of Oslo, Oslo N-0318, Norway.
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28
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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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Abstract
Toxocara canis has extraordinary abilities to survive for many years in the tissues of diverse vertebrate species, as well as to develop to maturity in the intestinal tract of its definitive canid host. Human disease is caused by larval stages invading musculature, brain and the eye, and immune mechanisms appear to be ineffective at eliminating the infection. Survival of T. canis larvae can be attributed to two molecular strategies evolved by the parasite. Firstly, it releases quantities of 'excretory-secretory' products which include lectins, mucins and enzymes that interact with and modulate host immunity. For example, one lectin (CTL-1) is very similar to mammalian lectins, required for tissue inflammation, suggesting that T. canis may interfere with leucocyte extravasation into infected sites. The second strategy is the elaboration of a specialised mucin-rich surface coat; this is loosely attached to the parasite epicuticle in a fashion that permits rapid escape when host antibodies and cells adhere, resulting in an inflammatory reaction around a newly vacated focus. The mucins have been characterised as bearing multiple glycan side-chains, consisting of a blood-group-like trisaccharide with one or two O-methylation modifications. Both the lectins and these trisaccharides are targeted by host antibodies, with anti-lectin antibodies showing particular diagnostic promise. Antibodies to the mono-methylated trisaccharide appear to be T. canis-specific, as this epitope is not found in the closely related Toxocara cati, but all other antigenic determinants are very similar between the two species. This distinction may be important in designing new and more accurate diagnostic tests. Further tools to control toxocariasis could also arise from understanding the molecular cues and steps involved in larval development. In vitro-cultivated larvae express high levels of four mRNAs that are translationally silenced, as the proteins they encode are not detectable in cultured larvae. However, these appear to be produced once the parasite has entered the mammalian host, as they are recognised by specific antibodies in infected patients. Elucidating the function of these genes, or analysing if micro-RNA translational silencing suppresses production of the proteins, may point towards new drug targets for tissue-phase parasites in humans.
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Affiliation(s)
- Rick M Maizels
- Institute of Immunology and Infection Research, University of Edinburgh, Ashworth Laboratories, West Mains Road, Edinburgh EH9 3JT, United Kingdom.
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Xie Y, Zhang Z, Niu L, Wang Q, Wang C, Lan J, Deng J, Fu Y, Nie H, Yan N, Yang D, Hao G, Gu X, Wang S, Peng X, Yang G. The mitochondrial genome of Baylisascaris procyonis. PLoS One 2011; 6:e27066. [PMID: 22046447 PMCID: PMC3203944 DOI: 10.1371/journal.pone.0027066] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Accepted: 10/10/2011] [Indexed: 11/17/2022] Open
Abstract
Background Baylisascaris procyonis (Nematoda: Ascaridida), an intestinal nematode of raccoons, is emerging as an important helminthic zoonosis due to serious or fatal larval migrans in animals and humans. Despite its significant veterinary and public health impact, the epidemiology, molecular ecology and population genetics of this parasite remain largely unexplored. Mitochondrial (mt) genomes can provide a foundation for investigations in these areas and assist in the diagnosis and control of B. procyonis. In this study, the first complete mt genome sequence of B. procyonis was determined using a polymerase chain reaction (PCR)-based primer-walking strategy. Methodology/Principal Findings The circular mt genome (14781 bp) of B. procyonis contained 12 protein-coding, 22 transfer RNA and 2 ribosomal RNA genes congruent with other chromadorean nematodes. Interestingly, the B. procyonis mtDNA featured an extremely long AT-rich region (1375 bp) and a high number of intergenic spacers (17), making it unique compared with other secernentean nematodes characterized to date. Additionally, the entire genome displayed notable levels of AT skew and GC skew. Based on pairwise comparisons and sliding window analysis of mt genes among the available 11 Ascaridida mtDNAs, new primer pairs were designed to amplify specific short fragments of the genes cytb (548 bp fragment) and rrnL (200 bp fragment) in the B. procyonis mtDNA, and tested as possible alternatives to existing mt molecular beacons for Ascaridida. Finally, phylogenetic analysis of mtDNAs provided novel estimates of the interrelationships of Baylisasaris and Ascaridida. Conclusions/Significance The complete mt genome sequence of B. procyonis sequenced here should contribute to molecular diagnostic methods, epidemiological investigations and ecological studies of B. procyonis and other related ascaridoids. The information will be important in refining the phylogenetic relationships within the order Ascaridida and enriching the resource of markers for systematic, population genetic and evolutionary biological studies of parasitic nematodes of socio-economic importance.
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Affiliation(s)
- Yue Xie
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Ya'an, China
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The morphology and genetic characterization of Iheringascaris goai n. sp. (Nematoda: Raphidascarididae) from the intestine of the silver whiting and spotted catfish off the central west coast of India. J Helminthol 2011; 86:353-62. [PMID: 21846431 DOI: 10.1017/s0022149x11000472] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In this study a new species of nematode, Iheringascaris goai n. sp., is reported from two fish hosts, including silver whiting, Sillago sihama, and spotted catfish, Arius maculatus, caught off the Central West Coast of India at Goa. The new species can be differentiated morphologically from I. inquies, the most closely related species collected from cohabiting marine fish. The distinguishing characteristics are distinct cuticular striations, a unilateral excretory system, the presence of dentigerous ridges on the inner margin of the lips and the ratio of oesophagus to body length. In males, the ratio of spicules to body length is higher and the number of pre-anal papillae is less in comparison to those in I. inquies. In addition, the tail curves ventrad in males, while in females, the vulva is post-equatorial. The sequence alignment of 18S rDNA and cytochrome c oxidase subunit I with sequences of known species selected from the same superfamily shows a significant difference. The morphological and molecular differences reported here can, therefore, be used to assign the specimen to a new species.
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Complete mitochondrial genomes of Baylisascaris schroederi, Baylisascaris ailuri and Baylisascaris transfuga from giant panda, red panda and polar bear. Gene 2011; 482:59-67. [PMID: 21621593 DOI: 10.1016/j.gene.2011.05.004] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2011] [Revised: 05/01/2011] [Accepted: 05/10/2011] [Indexed: 11/24/2022]
Abstract
Roundworms of the genus Baylisascaris are the most common parasitic nematodes of the intestinal tracts of wild mammals, and most of them have significant impacts in veterinary and public health. Mitochondrial (mt) genomes provide a foundation for studying epidemiology and ecology of these parasites and therefore may be used to assist in the control of Baylisascariasis. Here, we determined the complete sequences of mtDNAs for Baylisascaris schroederi, Baylisascaris ailuri and Baylisascaris transfuga, with 14,778 bp, 14,657 bp and 14,898 bp in size, respectively. Each mtDNA encodes 12 protein-coding genes, 22 transfer RNAs and 2 ribosomal RNAs, typical for other chromadorean nematodes. The gene arrangements for the three Baylisascaris species are the same as those of the Ascaridata species, but radically different from those of the Spirurida species. Phylogenetic analysis based on concatenated amino acid sequences of 12 protein-coding genes from nine nematode species indicated that the three Baylisascaris species are more closely related to Ascaris suum than to the three Toxocara species (Toxocara canis, Toxocara cati and Toxocara malaysiensis) and Anisakis simplex, and that B. ailuri is more closely related to B. transfuga than to B. schroeder. The determination of the complete mt genome sequences for these three Baylisascaris species (the first members of the genus Baylisascaris ever sequenced) is of importance in refining the phylogenetic relationships within the order Ascaridida, and provides new molecular data for population genetic, systematic, epidemiological and ecological studies of parasitic nematodes of socio-economic importance in wildlife.
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Toward next-generation sequencing of mitochondrial genomes — Focus on parasitic worms of animals and biotechnological implications. Biotechnol Adv 2010; 28:151-9. [DOI: 10.1016/j.biotechadv.2009.11.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Revised: 10/28/2009] [Accepted: 11/04/2009] [Indexed: 11/21/2022]
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Jex AR, Hall RS, Littlewood DTJ, Gasser RB. An integrated pipeline for next-generation sequencing and annotation of mitochondrial genomes. Nucleic Acids Res 2009; 38:522-33. [PMID: 19892826 PMCID: PMC2811008 DOI: 10.1093/nar/gkp883] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Mitochondrial (mt) genomics represents an understudied but important field of molecular biology. Increasingly, mt dysfunction is being linked to a range of human diseases, including neurodegenerative disorders, diabetes and impairment of childhood development. In addition, mt genomes provide important markers for systematic, evolutionary and population genetic studies. Some technological limitations have prevented the expanded generation and utilization of mt genomic data for some groups of organisms. These obstacles most acutely impede, but are not limited to, studies requiring the determination of complete mt genomic data from minute amounts of material (e.g. biopsy samples or microscopic organisms). Furthermore, post-sequencing bioinformatic annotation and analyses of mt genomes are time consuming and inefficient. Herein, we describe a high-throughput sequencing and bioinformatic pipeline for mt genomics, which will have implications for the annotation and analysis of other organellar (e.g. plastid or apicoplast genomes) and virus genomes as well as long, contiguous regions in nuclear genomes. We utilize this pipeline to sequence and annotate the complete mt genomes of 12 species of parasitic nematode (order Strongylida) simultaneously, each from an individual organism. These mt genomic data provide a rich source of markers for studies of the systematics and population genetics of a group of socioeconomically important pathogens of humans and other animals.
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Affiliation(s)
- Aaron R Jex
- Department of Veterinary Science, The University of Melbourne, Victoria 3030, Australia.
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Jex AR, Waeschenbach A, Hu M, van Wyk JA, Beveridge I, Littlewood DTJ, Gasser RB. The mitochondrial genomes of Ancylostoma caninum and Bunostomum phlebotomum--two hookworms of animal health and zoonotic importance. BMC Genomics 2009; 10:79. [PMID: 19210793 PMCID: PMC2656527 DOI: 10.1186/1471-2164-10-79] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Accepted: 02/11/2009] [Indexed: 11/22/2022] Open
Abstract
Background Hookworms are blood-feeding nematodes that parasitize the small intestines of many mammals, including humans and cattle. These nematodes are of major socioeconomic importance and cause disease, mainly as a consequence of anaemia (particularly in children or young animals), resulting in impaired development and sometimes deaths. Studying genetic variability within and among hookworm populations is central to addressing epidemiological and ecological questions, thus assisting in the control of hookworm disease. Mitochondrial (mt) genes are known to provide useful population markers for hookworms, but mt genome sequence data are scant. Results The present study characterizes the complete mt genomes of two species of hookworm, Ancylostoma caninum (from dogs) and Bunostomum phlebotomum (from cattle), each sequenced (by 454 technology or primer-walking), following long-PCR amplification from genomic DNA (~20–40 ng) isolated from individual adult worms. These mt genomes were 13717 bp and 13790 bp in size, respectively, and each contained 12 protein coding, 22 transfer RNA and 2 ribosomal RNA genes, typical for other secernentean nematodes. In addition, phylogenetic analysis (by Bayesian inference and maximum likelihood) of concatenated mt protein sequence data sets for 12 nematodes (including Ancylostoma caninum and Bunostomum phlebotomum), representing the Ascaridida, Spirurida and Strongylida, was conducted. The analysis yielded maximum statistical support for the formation of monophyletic clades for each recognized nematode order assessed, except for the Rhabditida. Conclusion The mt genomes characterized herein represent a rich source of population genetic markers for epidemiological and ecological studies. The strong statistical support for the construction of phylogenetic clades and consistency between the two different tree-building methods employed indicate the value of using whole mt genome data sets for systematic studies of nematodes. The grouping of the Spirurida and Ascaridida to the exclusion of the Strongylida was not supported in the present analysis, a finding which conflicts with the current evolutionary hypothesis for the Nematoda based on nuclear ribosomal gene data.
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Affiliation(s)
- Aaron R Jex
- Department of Veterinary Science, The University of Melbourne, Werribee, Victoria 3030, Australia.
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