Genetic characterization of Toxoplasma gondii isolates from China.
ABSTRACT Toxoplasma gondii infections are prevalent in humans and animals worldwide. In North America and Europe, T. gondii is highly clonal, consisting of three distinct lineages (Types I, II and III), whereas in South America, T. gondii is highly diverse with a few lineages expanded in the population. However, there is limited data on the diversity of T. gondii in Asia. Here we report the genetic characterization of T. gondii isolates from different hosts and geographical locations in China using the multilocus PCR-RFLP. A total of 17 T. gondii isolates from humans (3 strains), sheep (1 strain), pigs (5 strains) and cats (8 strains) were typed at 10 genetic markers including 9 nuclear loci SAG1, SAG2, SAG3, BTUB, GRA6, L358, PK1, c22-8, c29-2 and an apicoplast locus Apico. Four genotypes were revealed, including three previously reported and one new genotype. Three isolates belong to the clonal Type I lineage, one isolate belongs to the clonal Type II lineage, and the rest 13 isolates are grouped into two genotypes. This is the first report of genetic typing of T. gondii isolates from different hosts and geographical locations in China using a number of genetic markers, which has implications for the studies of population genetic structures of T. gondii, as well as for the prevention and control of T. gondii infections in humans and animals in China.
- SourceAvailable from: PubMed Central[Show abstract] [Hide abstract]
ABSTRACT: Cats are the definitive hosts of Toxoplasma gondii. The distribution of genetic diversity of T. gondii in cats is of importance to understand the transmission of this parasite. The objective of this study was to genetically characterize T. gondii isolates from cats in Yunnan province, southwestern China. Genomic DNA was extracted from 5-10 g cat tissue samples (brain, tongue, heart, and liver). Using multilocous polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technology, we determined genetic diversity of T. gondii isolates from cats in Yunnan province.Result: In total, 175 stray cats were tested for T. gondii DNA, respectively, 44 (25.14%) of which were found to be positive for the T. gondii B1 gene by PCR amplification. The positive DNA samples were typed at 11 genetic markers, including 10 nuclear markers, namely, SAG1, 5[prime]-3[prime]SAG2, alternative SAG2, SAG3, GRA6, L358, PK1, BTUB, c22-8, c29-2 and an apicoplast locus Apico. Of these, 16 isolates from cats were genotyped with data for more than 9 loci, revealed 5 genotypes in total, of which 11 of 16 samples were identified as ToxoDB#9, two samples may belong to genotye #225, one was Type II, one was ToxoDB#3, and one was ToxoDB#20 (http://toxodb.org/toxo/). The results of the present study indicated a wide distribution of T. gondii infection in cats in Yunnan province, which may pose significant public health concerns. To our knowledge, the present study is the first report of T. gondii prevalence and genotypes in cats in southwestern China, and the first report of Type II T. gondii from cats in China.Parasites & Vectors 04/2014; 7(1):178. · 3.25 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Toxoplasmosis, caused by the protozoan parasite Toxoplasma gondii, is one of the most common zoonosis worldwide, affecting a wide range of warm-blooded mammals and birds worldwide. However, no information on T. gondii infection in pet birds in China is available. Therefore, this study was performed to determine the prevalence of T. gondii infection in pet birds in Gansu province, China. A total of 687 blood samples were collected from pet birds (Carduelis spinus, Alauda gulgula, Cocothraustes migratorlus) in three representative administrative regions in Gansu province, northwest China between August 2011 and September 2012 T. gondii antibodies were determined using the modified agglutination test (MAT). Genomic DNA was extracted from the brain tissues of seropositive pet birds and T. gondii B1 gene was amplified using a semi-nested PCR.DNA samples giving positive B1 amplification were then genetically characterized using multi-locus PCR-RFLP. The overall T. gondii seroprevalence was 11.21% (77/687). C. spinus had the highest T. gondii seroprevalence (11.65%), followed by A. arvensis (11.39%) and C. migratorlus (5.26%), these differences were not statistically significant (P > 0.05). Of 77 DNA samples, 8 were positive for the T. gondii B1 gene, four showed complete genotyping results. Only one genotype (the Type II variant: ToxoDB genotype #3) was identified. The results of the present survey indicated the presence of T. gondii infection in pet birds in Gansu province, China. These data provide base-line information for the execution of control strategies against T. gondii infection in pet birds. To our knowledge, this is the first report documenting the occurrence of T. gondii prevalence and genotype in pet birds in China.Parasites & Vectors 04/2014; 7(1):152. · 3.25 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Genetic diversity of T. gondii is a concern of many studies, due to the biological and epidemiological diversity of this parasite. The present study examined sequence variation in rhoptry protein 17 (ROP17) gene among T. gondii isolates from different hosts and geographical regions. The rop17 gene was amplified and sequenced from 10 T. gondii strains, and phylogenetic relationship among these T. gondii strains was reconstructed using maximum parsimony (MP), neighbor-joining (NJ), and maximum likelihood (ML) analyses. The partial rop17 gene sequences were 1375 bp in length and A+T contents varied from 49.45% to 50.11% among all examined T. gondii strains. Sequence analysis identified 33 variable nucleotide positions (2.1%), 16 of which were identified as transitions. Phylogeny reconstruction based on rop17 gene data revealed two major clusters which could readily distinguish Type I and Type II strains. Analyses of sequence variations in nucleotides and amino acids among these strains revealed high ratio of nonsynonymous to synonymous polymorphisms (>1), indicating that rop17 shows signs of positive selection. This study demonstrated the existence of slightly high sequence variability in the rop17 gene sequences among T. gondii strains from different hosts and geographical regions, suggesting that rop17 gene may represent a new genetic marker for population genetic studies of T. gondii isolates.TheScientificWorldJournal. 01/2014; 2014:349325.