[Genetic diversity of Sparganum isolates from snakes in Hunan Province based on mitochondrial nad4 and nad5 genes].

OBJECTIVE: To investigate the genetic diversity and phylogenetic relationship of Sparganum isolates from snakes in Hunan Province. METHODS: The partial mitochondrial NADH dehydrogenase subunit 4 (pnad4) and NADH dehydrogenase subunit 5 (pnad5) genes were amplified using a PCR assay in 7 Sparganum isolates from snakes in Hunan Province and the amplification product was sequenced. The homology and genetic evolution were investigated using the software DNAMAN 7.0, MegAlign, DnaSP 5.0 and MEGA 5.0. RESULTS: The pnad4 and pnad5 gene sequences were approximately 578 bp and 484 bp in length in the 7 Sparganum isolates from Hunan Province, and the percentages of genetic variations were 0 to 2.8% and 0 to 0.8%, respectively. There were 4 haplotypes detected in both the pnad4 and pnad5 genes, with global haplotype diversities of 0.810 ± 0.016 and 0.905 ± 0.011, nucleotide diversities of 0.006 ± 0.005 and 0.004 ± 0.003, and mean nucleotide variations of 3.960 and 1.905, respectively. Phylogenetic analysis showed that all 7 Sparganum isolates from snakes in Hunan Province were clustered into the same branch with Spirometra erinaceieuropaei isolates from different regions/hosts in the world, which belonged to S. erinaceieuropaei, which were close to Diphyllobothrium latum and far from other tapeworms. CONCLUSIONS: There is a low genetic variation in snake-derived S. erinaceieuropaei isolates from Hunan Province, and both pnad4 and pnad5 genes may be potential molecular genetic markers for identification of S. erinaceieuropaei.

Genetic diversity of Sparganum isolates from snakes in Hunan Province based on mitochondrial nad4 and nad5 genes / 中国血吸虫病防治杂志

Objective To investigate the genetic diversity and phylogenetic relationship of Sparganum isolates from snakes in Hunan Province. Methods The partial mitochondrial NADH dehydrogenase subunit 4 (pnad4) and NADH dehydrogenase subunit 5 (pnad5) genes were amplified using a PCR assay in 7 Sparganum isolates from snakes in Hunan Province and the amplification product was sequenced. The homology and genetic evolution were investigated using the software DNAMAN 7.0, MegAlign, DnaSP 5.0 and MEGA 5.0. Results The pnad4 and pnad5 gene sequences were approximately 578 bp and 484 bp in length in the 7 Sparganum isolates from Hunan Province, and the percentages of genetic variations were 0 to 2.8% and 0 to 0.8%, respectively. There were 4 haplotypes detected in both the pnad4 and pnad5 genes, with global haplotype diversities of 0.810 ± 0.016 and 0.905 ± 0.011, nucleotide diversities of 0.006 ± 0.005 and 0.004 ± 0.003, and mean nucleotide variations of 3.960 and 1.905, respectively. Phylogenetic analysis showed that all 7 Sparganum isolates from snakes in Hunan Province were clustered into the same branch with Spirometra erinaceieuropaei isolates from different regions/hosts in the world, which belonged to S. erinaceieuropaei, which were close to Diphyllobothrium latum and far from other tapeworms. Conclusion There is a low genetic variation in snake-derived S. erinaceieuropaei isolates from Hunan Province, and both pnad4 and pnad5 genes may be potential molecular genetic markers for identification of S. erinaceieuropaei.

Distinguishing Echinococcus granulosus sensu stricto genotypes G1 and G3 with confidence: A practical guide.

Cystic echinococcosis (CE), a zoonotic disease caused by tapeworms of the species complex Echinococcus granulosus sensu lato, represents a substantial global health and economic burden. Within this complex, E. granulosus sensu stricto (genotypes G1 and G3) is the most frequent causative agent of human CE. Currently, there is no fully reliable method for assigning samples to genotypes G1 and G3, as the commonly used mitochondrial cox1 and nad1 genes are not sufficiently consistent for the identification and differentiation of these genotypes. Thus, a new genetic assay is required for the accurate assignment of G1 and G3. Here we use a large dataset of near-complete mtDNA sequences (n = 303) to reveal the extent of genetic variation of G1 and G3 on a broad geographical scale and to identify reliable informative positions for G1 and G3. Based on extensive sampling and sequencing data, we developed a new method, that is simple and cost-effective, to designate samples to genotypes G1 and G3. We found that the nad5 is the best gene in mtDNA to differentiate between G1 and G3, and developed new primers for the analysis. Our results also highlight problems related to the commonly used cox1 and nad1. To guarantee consistent identification of G1 and G3, we suggest using the sequencing of the nad5 gene region (680 bp). This region contains six informative positions within a relatively short fragment of the mtDNA, allowing the differentiation of G1 and G3 with confidence. Our method offers clear advantages over the previous ones, providing a significantly more consistent means to distinguish G1 and G3 than the commonly used cox1 and nad1.

Molecular Identification of Diphyllobothrium nihonkaiense from 3 Human Cases in Heilongjiang Province with a Brief Literature Review in China.

Human diphyllobothriasis is a widespread fish-borne zoonosis caused by the infection with broad tapeworms belonging to the genus Diphyllobothrium. In mainland China, so far 20 human cases of Diphyllobothrium infections have been reported, and the etiologic species were identified as D. latum and D. nihonkaiense based on morphological characteristics or molecular analysis. In the present study, proglottids of diphyllobothriid tapeworms from 3 human cases that occurred in Heilongjiang Province, China were identified as D. nihonkaiense by sequencing mitochondrial cytochrome c oxidase subunit I (cox1) and NADH dehydrogenase subunit 5 (nad5) genes. Two different cox1 gene sequences were obtained. One sequence showed 100% homology with those from humans in Japan. The remaining cox1 gene sequence and 2 different nad5 gene sequences obtained were not described previously, and might reflect endemic genetic characterizations. D. nihonkaiense might also be a major causative species of human diphyllobothriasis in China. Meanwhile, the finding of the first pediatric case of D. nihonkaiense infection in China suggests that infants infected with D. nihonkaiense should not be ignored.

Molecular Identification of Diphyllobothrium nihonkaiense from 3 Human Cases in Heilongjiang Province with a Brief Literature Review in China

Human diphyllobothriasis is a widespread fish-borne zoonosis caused by the infection with broad tapeworms belonging to the genus Diphyllobothrium. In mainland China, so far 20 human cases of Diphyllobothrium infections have been reported, and the etiologic species were identified as D. latum and D. nihonkaiense based on morphological characteristics or molecular analysis. In the present study, proglottids of diphyllobothriid tapeworms from 3 human cases that occurred in Heilongjiang Province, China were identified as D. nihonkaiense by sequencing mitochondrial cytochrome c oxidase subunit I (cox1) and NADH dehydrogenase subunit 5 (nad5) genes. Two different cox1 gene sequences were obtained. One sequence showed 100% homology with those from humans in Japan. The remaining cox1 gene sequence and 2 different nad5 gene sequences obtained were not described previously, and might reflect endemic genetic characterizations. D. nihonkaiense might also be a major causative species of human diphyllobothriasis in China. Meanwhile, the finding of the first pediatric case of D. nihonkaiense infection in China suggests that infants infected with D. nihonkaiense should not be ignored.