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Genetic variability within and among Haemonchus contortus isolates from goats and sheep in China.

Yin F, Gasser RB, Li F, Bao M, Huang W, Zou F, Zhao G, Wang C, Yang X, Zhou Y, Zhao J, Fang R, Hu M - Parasit Vectors (2013)

Bottom Line: Haemonchus contortus (order Strongylida) is a common parasitic nematode infecting small ruminants and causing significant economic losses worldwide.The results revealed high within-population variations, low genetic differentiation and high gene flow among different populations of H. contortus in China.The present results could have implications for studying the epidemiology and ecology of H. contortus in China.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China. mhu@mail.hzau.edu.cn.

ABSTRACT

Background: Haemonchus contortus (order Strongylida) is a common parasitic nematode infecting small ruminants and causing significant economic losses worldwide. Knowledge of genetic variation within and among H. contortus populations can provide a foundation for understanding transmission patterns, the spread of drug resistance alleles and might assist in the control of haemonchosis.

Methods: 152 H. contortus individual adult worms were collected from seven different geographical regions in China. The second internal transcribed spacer (ITS-2) of the nuclear ribosomal DNA and mitochondrial nicotinamide dehydrogenase subunit 4 gene (nad4) were amplified by polymerase chain reaction (PCR) and sequenced directly. The sequence variations and population genetic diversities were determined.

Results: Nucleotide sequence analyses revealed 18 genotypes (ITS-2) and 142 haplotypes (nad4) among the 152 worms, with nucleotide diversities of 2.6% and 0.027, respectively, consistent with previous reports from other countries, including Australia, Brazil, Germany, Italy, Malaysia, Sweden, the USA and Yemen. Population genetic analyses revealed that 92.4% of nucleotide variation was partitioned within populations; there was no genetic differentiation but a high gene flow among Chinese populations; some degree of genetic differentiation was inferred between some specimens from China and those from other countries.

Conclusions: This is the first study of genetic variation within H. contortus in China. The results revealed high within-population variations, low genetic differentiation and high gene flow among different populations of H. contortus in China. The present results could have implications for studying the epidemiology and ecology of H. contortus in China.

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Sampling sites. Seven different geographical locations in China (longitudes and latitudes given in Table 1) at which adult Haemonchus contortus were collected from sheep or goats.
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Figure 1: Sampling sites. Seven different geographical locations in China (longitudes and latitudes given in Table 1) at which adult Haemonchus contortus were collected from sheep or goats.

Mentions: In total, 152 individual adult specimens of H. contortus were collected from the abomasa of slaughtered sheep or goats from seven geographical locations in tropical to subtropical climate zones and six provinces of China (Figure 1 and Table 1). Geographical locations were separated by distances of 370 to 4000 km. Samples from Liaoning and Heilongjiang were from sheep, whereas those from other regions were from goats. The adult specimens of H. contortus (17 to 24 per population) were washed extensively in physiological saline, stored in 70% ethanol and then sent to the College of Veterinary Medicine, Huazhong Agricultural University, Wuhan. Upon arrival, individual worms were identified morphologically, according to Lichtenfels et al. (1994) [15].


Genetic variability within and among Haemonchus contortus isolates from goats and sheep in China.

Yin F, Gasser RB, Li F, Bao M, Huang W, Zou F, Zhao G, Wang C, Yang X, Zhou Y, Zhao J, Fang R, Hu M - Parasit Vectors (2013)

Sampling sites. Seven different geographical locations in China (longitudes and latitudes given in Table 1) at which adult Haemonchus contortus were collected from sheep or goats.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3852563&req=5

Figure 1: Sampling sites. Seven different geographical locations in China (longitudes and latitudes given in Table 1) at which adult Haemonchus contortus were collected from sheep or goats.
Mentions: In total, 152 individual adult specimens of H. contortus were collected from the abomasa of slaughtered sheep or goats from seven geographical locations in tropical to subtropical climate zones and six provinces of China (Figure 1 and Table 1). Geographical locations were separated by distances of 370 to 4000 km. Samples from Liaoning and Heilongjiang were from sheep, whereas those from other regions were from goats. The adult specimens of H. contortus (17 to 24 per population) were washed extensively in physiological saline, stored in 70% ethanol and then sent to the College of Veterinary Medicine, Huazhong Agricultural University, Wuhan. Upon arrival, individual worms were identified morphologically, according to Lichtenfels et al. (1994) [15].

Bottom Line: Haemonchus contortus (order Strongylida) is a common parasitic nematode infecting small ruminants and causing significant economic losses worldwide.The results revealed high within-population variations, low genetic differentiation and high gene flow among different populations of H. contortus in China.The present results could have implications for studying the epidemiology and ecology of H. contortus in China.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China. mhu@mail.hzau.edu.cn.

ABSTRACT

Background: Haemonchus contortus (order Strongylida) is a common parasitic nematode infecting small ruminants and causing significant economic losses worldwide. Knowledge of genetic variation within and among H. contortus populations can provide a foundation for understanding transmission patterns, the spread of drug resistance alleles and might assist in the control of haemonchosis.

Methods: 152 H. contortus individual adult worms were collected from seven different geographical regions in China. The second internal transcribed spacer (ITS-2) of the nuclear ribosomal DNA and mitochondrial nicotinamide dehydrogenase subunit 4 gene (nad4) were amplified by polymerase chain reaction (PCR) and sequenced directly. The sequence variations and population genetic diversities were determined.

Results: Nucleotide sequence analyses revealed 18 genotypes (ITS-2) and 142 haplotypes (nad4) among the 152 worms, with nucleotide diversities of 2.6% and 0.027, respectively, consistent with previous reports from other countries, including Australia, Brazil, Germany, Italy, Malaysia, Sweden, the USA and Yemen. Population genetic analyses revealed that 92.4% of nucleotide variation was partitioned within populations; there was no genetic differentiation but a high gene flow among Chinese populations; some degree of genetic differentiation was inferred between some specimens from China and those from other countries.

Conclusions: This is the first study of genetic variation within H. contortus in China. The results revealed high within-population variations, low genetic differentiation and high gene flow among different populations of H. contortus in China. The present results could have implications for studying the epidemiology and ecology of H. contortus in China.

Show MeSH
Related in: MedlinePlus