Genetic Variation of Porcine Circovirus Type 2 Isolate 201105ZJ

[Objective] This study aimed to investigate the genetic variation of porcine circovirus type 2 （PCV2） in China. [Method] The strain was isolated from infected samples by cel passage and preliminarily identified by PCR and IFA. Ful-length genome of the isolated strain was obtained by specific amplification for homology and phylogenetic analysis. [Result] A PCV2 strain was successful y isolated and named 201105ZJ, which could proliferate in PK15 cel lines. Specific fragments could be amplified by specific PCR assay. According to results of IFA assay, specif-ic immunofluorescence was observed; the TCID50 was low （102.67）; the ful-length genome sequence of the isolated strain was 1 768 bp, sharing 94.1%-96.8% ho-mology with 13 reference strains; to be specific, the isolated strain exhibited the highest homology of 96.8% with AF055392PCV2a; the isolated strain 201105ZJ and reference strain AF055392 belonged to genotype PCV2a, exhibiting a distant genetic relationship with genotype PCV2c. [Conclusion] Characteristics of genetic variation of PCV2 isolate 201105ZJ provided theoretical basis for vaccine development, investi-gation of PCV2 pathogenesis, and prevention and control of porcine circovirus-as-sociated diseases （PCVAD） in East China.

Follow up of infection of chacma baboons with inoculum containing a and non-a genotypes of hepatitis B virus

AIM: To determine whether one genotype (A or non-A genotypes of HBV) predominated over the other during the course of HBV infection.METHODS: Four baboons were inoculated with HBV. DNA was extracted from serum obtained at monthly intervals postinoculation for 52 weeks and HBV DNA was amplified using primers specific for the core region containing an insert characteristic of genotype A (nt 2 354-2 359, numbering from the EcoRI site). The amplicons were cloned into PCRScriptTM and a minimum of 15 clones per time point were sequenced in both directions.RESULTS: Both genotypes persisted for the entire followup period of 52 weeks. Genotype non-A predominated in two baboons and genotype A in one baboon. Neither genotype predominated in the fourth baboon, as shown at a 5 % level of testing.CONCLUSION: No conclusions concerning the dominance of either genotype or the natural progression or replication rates of HBV could be drawn because the pattern of the genotypes found may have been caused by sampling fluctuations at the time of DNA extraction and cloning as a result of the very low viral loads in the baboon sera.

Simultaneous virus identification and characterization of severe unexplained pneumonia cases using a metagenomics sequencing technique

Many viruses can cause respiratory diseases in humans.Although great advances have been achieved in methods of diagnosis,it remains challenging to identify pathogens in unexplained pneumonia(UP) cases.In this study,we applied next-generation sequencing(NGS) technology and a metagenomic approach to detect and characterize respiratory viruses in UP cases from Guizhou Province,China.A total of 33 oropharyngeal swabs were obtained from hospitalized UP patients and subjected to NGS.An unbiased metagenomic analysis pipeline identified 13 virus species in 16 samples.Human rhinovirus C was the virus most frequently detected and was identified in seven samples.Human measles virus,adenovirus B 55 and coxsackievirus A10 were also identified.Metagenomic sequencing also provided virus genomic sequences,which enabled genotype characterization and phylogenetic analysis.For cases of multiple infection,metagenomic sequencing afforded information regarding the quantity of each virus in the sample,which could be used to evaluate each viruses' role in the disease.Our study highlights the potential of metagenomic sequencing for pathogen identification in UP cases.