Novel genotypes and multilocus genotypes of Enterocytozoon bieneusi in two wild rat species in China: potential for zoonotic transmission.

Enterocytozoon bieneusi is an opportunistic pathogen in immunodeficient patients. Although this pathogen has been reported in many domestic animals, few data are available about the occurrence of E. bieneusi in wild rats. In the current study, a total of 228 fecal samples from two wild rat species (Leopoldamys edwardsi and Berylmys bowersi) in China were examined by a nested PCR-based sequencing approach employing the internal transcribed spacer (ITS) region of nuclear ribosomal DNA. The overall prevalence of E. bieneusi in wild rats was 33.3% (76/228), with 35.1% (39/111) in L. edwardsi and 31.6% (37/117) in B. bowersi. Ten E. bieneusi genotypes (including four known and six novel genotypes) were identified, with the novel CQR-2 (n = 15) as the predominant genotype. Phylogenetic analysis indicated that ten genotypes in the present study belong to zoonotic group 1, which contains many genotypes in humans. Furthermore, multilocus sequence typing (MLST) analysis showed that 19 ITS-positive samples were successfully amplified at three microsatellites and one minisatellite, forming 18 multilocus genotypes (MLGs). This is the first report of E. bieneusi infection in the wild rats L. edwardsi and B. bowersi. Our findings suggest that wild rats could be a significant source of human infection, including contaminated food and water.

Characterization of the complete mitochondrial genome of the echinostome Echinostoma miyagawai and phylogenetic implications.

Echinostomes are important intestinal foodborne parasites. Despite their significance as pathogens, characterization of the molecular biology and phylogenetics of these parasites are limited. In the present study, we determined the entire mitochondrial (mt) genome of the echinostome Echinostoma miyagawai (Hunan isolate) and examined the phylogenetic relationship with selected members of the suborder Echinostomata. The complete mt genome of E. miyagawai (Hunan isolate) was 14,468 bp in size. This circular mt genome contained 12 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and one non-coding region. The gene order and genomic content were identical with its congeners. Phylogenetic analyses (maximum parsimony, maximum likelihood, and Bayesian inference) based on the concatenated amino acid sequences of 12 protein-coding genes strongly supported monophyly for the genus Echinostoma; however, they rejected monophyly for the family Echinostomatidae and the genus Fasciola. The mt genomic data described in this study provides useful genetic markers for studying the population genetics, molecular biology, and phylogenetics of these echinostomes.

The Complete Mitochondrial Genome of the Caecal Fluke of Poultry, Postharmostomum commutatum, as the First Representative from the Superfamily Brachylaimoidea.

Postharmostomum commutatum (Platyhelminthes: Brachylaimoidea), a parasite of the caeca of poultry, has been frequently reported from many countries and regions, including China. However, the molecular epidemiology, population genetics and phylogenetics of this parasite are poorly understood. In the present study, we determined and characterized the complete mitochondrial (mt) genome of P. commutatum, as the first representative from the superfamily Brachylaimoidea. The mt genome of P. commutatum is a circular DNA molecule of 13,799 bp in size and encodes the complete set of 36 genes (12 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes) as well as a typical control region. The mt genome of P. commutatum presents a clear bias in nucleotide composition with a negative AT-skew on average (-0.306) and a positive GC-skew on average (0.466). Phylogenetic analyses showed that P. commutatum (superfamily Brachylaimoidea) and other ten members of the order Diplostomida were recovered as sister groups of the order Plagiorchiida, indicating that the order Diplostomida is paraphyletic. This is the first mt genome of any member of the superfamily Brachylaimoidea and should represent a rich source of genetic markers for molecular epidemiological, population genetic and phylogenetic studies of parasitic flukes of socio-economic importance in poultry.

Comparative analysis of mitochondrial DNA datasets indicates that Toxascaris leonina represents a species complex.

BACKGROUND: Toxascaris leonina is one of the most common intestinal parasites of canids and felids. In this study, we characterised the entire mitochondrial (mt) genome sequence of T. leonina from the cheetah and compared it with that of T. leonina from the dog. RESULTS: The entire mt genome sequence of T. leonina from the cheetah is 14,685 bp in size, which is 375 bp longer than that from the dog, and it is 408 bp longer than that from the South China tiger. The overall nucleotide sequence (except for the non-coding region) identity was 92.8% between the two mt genomes of T. leonina from the cheetah and the dog. For the 12 protein-coding genes, sequence difference between T. leonina from the cheetah and the dog was 5.0-9.7% at the nucleotide level and 1.0-7.2% at the amino acid level. Moreover, comparison of mt cox1 sequences among T. leonina isolates (n = 23) from different hosts revealed substantial nucleotide differences (10.6%). Phylogenetic analysis showed the separation of T. leonina from canid and felid hosts into three distinct clades. CONCLUSIONS: Taken together, these mtDNA datasets indicate that T. leonina from canid and felid hosts represents a species complex. Our results have implications for further studies of the molecular epidemiology, systematics and population genetics of this nematode.

Molecular Prevalence and Genetic Characterization of Toxoplasma gondii in Wild Birds in Hunan Province, China.

Toxoplasma gondii is a ubiquitous apicomplexan parasite of warm-blooded animals and humans. However, limited information is available about T. gondii infection in wild birds. In this study, 239 wild birds were collected from Hunan province of China, including 38 chestnut bunting, 44 olive-backed pipit, 26 yellow-breasted bunting, and 131 tree sparrows. Genomic DNA of brain tissues were extracted and assayed by B1 gene, and the positive samples were genotyped at 10 genetic markers [SAG1, SAG2 (5'+3' SAG2, alter. SAG2), SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico] using multilocus nested-PCR-restriction fragment length polymorphism technology. The results showed that 13 (5.51%) of the 239 wild birds were positive for T. gondii. Among them, three samples have completely genotyped at all loci, and were identified as ToxoDB #10. Our results have indicated that wild birds can carry and potentially disseminate the T. gondii. This is the first report of the molecular prevalence and genetic characterization of T. gondii in wild birds in Hunan province, China. Further research should be investigated to understand weather T. gondii can be transmitted from wild birds to other animals or humans.