Differentiation of Haemonchus placei from H. contortus (Nematoda: Trichostrongylidae) by the ribosomal DNA second internal transcribed spacer

Stevenson, Lisa A.; Chilton, Neil B.; Gasser, Robin B.

doi:10.1016/0020-7519(94)00156-i

Cited by 165 publications

(105 citation statements)

References 19 publications

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“…The alignments performed with our results confirmed the specificity of the ITS-2 domain: five repeated different nucleotides for ITS-2 between S. spiculoptera and S. asymmetrica and only three between H. contortus and H. placei [36].…”

Section: Discussionsupporting

confidence: 81%

“…Comparisons of genetic sequences from both Internal Transcribed Spacers (ITS-1 and ITS-2) which are known as specific level markers are now used to detect polymorphism [18,23,42]. Yet, no ITS sequence difference has been displayed within species morphs [9,32,36]. Mitochondrial DNA has also been investigated to resolve the polymorphic issue [42] or to assess cryptic species [7].…”

Section: Introductionmentioning

confidence: 99%

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Spiculopteragia mathevossianiRuchliadev, 1948 is the minor morph ofSpiculopteragia spiculoptera(Gushanskaya, 1931): molecular evidence

2006

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-Although Spiculopteragia spiculoptera is primarily a parasite of cervids, it can also but less often contaminate domestic livestock. Little is known about its epidemiology and its pathogenicity in domestic ruminants and other unusual cervid species. Its taxonomic status remains unclear since the hypothesis of morphological polymorphism among males has been proposed. However, accurate taxonomy is fundamental in the identification and survey of potentially pathogenic species of parasites. The second internal transcribed spacer of rDNA (ITS-2) and the mitochondrial (mt) DNA-derived ND4 gene were used to study the polymorphism hypothesis for S. spiculoptera. ND4 evolves more quickly than ITS-2 and is considered to be more discriminant in the characterization of closely related species. DNA sequences of ITS-2 and ND4 were studied in 18 individual males of morphological type spiculoptera and in 3 of morphological type of mathevossiani from Red deer (Cervus elaphus), Roe deer (Capreolus capreolus) and Chamois (Rupicapra rupicapra). Intraindividual ITS-2 variations were detected within and between each morphotype of Spiculopteragia but these differences did not separate the two morphs mathevossiani and spiculoptera. Similarly, although ND4 showed a high level of nucleotide substitution, the morphotypes S. mathevossiani and S. spiculoptera were clustered together. Our genetic data support the dimorphic male hypothesis for the species S. spiculoptera. mitochondrial DNA / second internal transcribed spacer (ITS-2) / Spiculopteragia spiculoptera / Spiculopteragia mathevossiani / polymorphism

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Section: Discussionsupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Spiculopteragia mathevossianiRuchliadev, 1948 is the minor morph ofSpiculopteragia spiculoptera(Gushanskaya, 1931): molecular evidence

2006

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“…Differences in the morphology of the infective larvae (L3) have also been reported, with H. placei L3s longer, more robust, and with longer sheath tail than those of H. contortus (SANTIAGO, 1968;VAN WYK et al, 2004). There are also several approaches using molecular techniques that can be employed do differentiate H. placei from H. contortus, including the use of PCR primers to amplify ribosomal RNA genes (ZARLENGA et al, 1994), and differences in mitochondrial ND4 gene sequences (BLOUIN et al, 1997) and in the ribosomal DNA second internal transcribed spacer sequences (STEVENSON et al, 1995;BRASIL et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Differentiation of Haemonchus placei from Haemonchus contortus by PCR and by morphometrics of adult parasites and third stage larvae

Santos

Amarante

Silva

et al. 2014

Rev. Bras. Parasitol. Vet.

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Molecular and morphological methods were evaluated to distinguish between Haemonchus contortus and Haemonchus placei species. A total of 141 H. contortus and 89 H. placei male adult specimens collected from artificially infected lambs were identified individually by PCR analysis, using a species-specific primer pair. These PCR results were used as gold standard for Haemonchus spp. identification. Haemonchus placei presented higher mean spicule and barb lengths than H. contortus (P<0.05). However, some measurements overlapped. For this reason, a discriminate function did not allow the correct identification of 13 H. contortus and one H. placei specimen. The sheath tail length of the third stage larvae (L3), which comprises the distance between the tip of the larval tail and the end of the sheath tail, were measured. Only three of the 485 H. placei larvae (0.619%) had a sheath tail shorter than 85 µm, while only four of the 500 H. contortus larvae (0.8%) presented a sheath tail longer than 85 µm. The results indicated that 6.09% of the male adult specimens would be misclassified based on the discriminate function, while only 0.71% of infective larvae would be misclassified. Therefore, identification of L3 can be used as the first method to indicate the presence of H. placei and/ or H. contortus in a population of domestic ruminants.Keywords: Diagnosis, Trichostrongyloidea, molecular biology, ruminants, epidemiology. ResumoMétodos moleculares e morfológicos foram avaliados para a identificação de Haemonchus contortus e Haemonchus placei. No total, 141 H. contortus e 89 H. placei machos adultos, obtidos de cordeiros artificialmente infectados, foram identificados individualmente por PCR com o emprego de um par de "primers" espécie-específico. Esses resultados da análise por PCR foram considerados como padrão para a identificação das espécies de Haemonchus. Haemonchus placei apresentou valores médios de espículos e ganchos superiores aos de H. contortus (P<0,05). Entretanto, houve sobreposição de alguns valores. Por essa razão, a função discriminante não permitiu a identificação correta de 13 exemplares de H. contortus e de um, de H. placei. Foi medida a cauda da bainha de larvas infectantes (L3), que compreende a distância entre a ponta da cauda da larva e a ponta da cauda da bainha. Apenas três das 485 L3 de H. placei (0,619%) apresentaram a cauda da bainha com medida inferior a 85 µm e somente em quatro das 500 L3 de H. contortus (0,8%) essa medida foi superior a 85 µm. Os resultados demonstraram que 6,09% dos machos adultos seriam identificados erroneamente com base na função discriminante, enquanto a identificação incorreta de L3 seria de apenas 0,71%. Portanto, a identificação de L3 pode ser utilizada como método inicial para indicar a presença de H. placei e/ou H. contortus em uma população de ruminantes domésticos.

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“…Normally, nematode parasites like T. canis, T. cati and T. leonina are detected by microscopic analysis and serological tests but both these methods are incapable of differentiating closely related taxa such as T. canis and T. cati (Van Knapen and Buijs 1993). In comparison, the second internal transcribed spacer (ITS-2) region, an insertion between the 5.8S and large subunit rRNA gene, has proven to be particularly valuable in resolving the taxonomic status of various parasitic groups including cestodes (Bowles et al 1995), trematodes (Blair et al 1996) and nematodes (Hoste et al 1995, Stevenson et al 1995. ITS-2 sequence has been utilised to identify single eggs of strongyloid nematodes to the species level (Campbell et al 1995) and for differentiating ascaridoid infections in dog, fox and cat (Jacobs et al 1997).…”

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confidence: 99%

Detection and molecular characterization of ascarid nematode infection (Toxascaris leonina and Toxocara cati) in captive Asiatic lions (Panthera leo persica)

Pawar

Lakshmikantan

Hasan

et al. 2012

Acta Parasitologica

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The objective of this study was to investigate the ascarid infection in Asiatic lions using scat samples, based on microscopic analysis, PCR amplification of the ITS-2 region of ribosomal DNA and sequence analysis of the amplicons. Microscopic analysis indicated the presence of eggs of Toxascaris leonina in eleven of the sixteen scat samples analysed and in one of these eleven scats eggs of Toxocara cati were also detected. In five of the scats eggs were not detectable. The presence of T. leonina in all the infected samples was also confirmed by PCR amplification of the ITS-2 of ribosomal RNA gene and five of these also showed amplicons corresponding to T. cati, respectively. Toxocara canis infection was not observed in any of the scat samples. Nucleotide sequence analysis of the ITS-2 region indicated 97% to 99% similarity with T. leonina and T. cati, respectively. To our knowledge, this is the first molecular characterization of ascarid infection in captive Asiatic lions from a zoological garden of India. This study also indicates that Asiatic lions are more prone to infection either with T. leonina or T. cati and the parasite is not host specific.

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Differentiation of Haemonchus placei from H. contortus (Nematoda: Trichostrongylidae) by the ribosomal DNA second internal transcribed spacer

Cited by 165 publications

References 19 publications

Spiculopteragia mathevossianiRuchliadev, 1948 is the minor morph ofSpiculopteragia spiculoptera(Gushanskaya, 1931): molecular evidence

Spiculopteragia mathevossianiRuchliadev, 1948 is the minor morph ofSpiculopteragia spiculoptera(Gushanskaya, 1931): molecular evidence

Differentiation of Haemonchus placei from Haemonchus contortus by PCR and by morphometrics of adult parasites and third stage larvae

Detection and molecular characterization of ascarid nematode infection (Toxascaris leonina and Toxocara cati) in captive Asiatic lions (Panthera leo persica)

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