ABSTRACT
To investigate the relationship of the variation of virulence and the external capsid proteins of the pandemic duck hepatitis A virus type 1(DHAV-1) isolates,the virulence,cross neutralization assays and the complete sequence of the virion protein 1(VP1) gene of nine virulent DHAV-1 strains,which were isolated from infected ducklings with clinical symptoms in Shandong province of China in 2007-2008,were tested.The fifth generation duck embryo allantoic liquids of the 9 isolates were tested on 12-day-old duck embryos and on 7-day-old ducklings for the median embryonal lethal doses(ELD50s) and the median lethal doses(LD50s),respectively.The results showed that the ELD5s of embryonic duck eggs of the 9 DHAV-1 isolates were between 1.9 × 106/mL to 1.44 × 107/mL,while the LD50s were 2.39 × 105/mL to 6.15 × 106/mL.Cross-neutralization tests revealed that the 9 DHAV-1 isolates were completely neutralized by the standard serum and the hyperimmune sera against the 9 DHAV-1 isolates,respectively.Compared with other virulent,moderate virulent,attenuated vaccine and mild strains,the VP1 genes of the 9 strains shared 89.8％-99.7％ similarity at the nucleotide level and 92.4％-99.6％ at amino acid level with other DHAV-1 strains.There were three hypervariable regions at the C-terminus(as 158-160,180-193 and 205-219) and other variable points in VPI protein,but which didn't cause virulence of DHAV-1 change.
ABSTRACT
To investigate molecular epidemiology of DuCV in Cherry Valley ducks in China,the complete genomes of six DuCV strains,which were detected from Cherry Valley ducks in China between 2007 and 2008,were sequenced.Sequence and phylogenetic analysis were carried out to compare these six strains with another 27DuCV strains from Mulard duck,Muscovy duck,Pekin ducks and Mule duck.The analysis showed that the six DuCV strains exhibited typical genetic features of the family of DuCV,such as a stem-loop structure,three major open reading frames (Rep,Cap and ORF3),four intergenic repeats and the conserved motifs for rolling circle replication and for the dNTP binding domain located in the Rep protein.Phylogenetic analysis of the nucleotide sequences of the complete genome and Cap gene of these strains together with those that have been previously published demonstrated two distinct DuCV genotypes.The DuCV strains with complete genomes containing 1988and 1989 nucleotides clustered in genotype A,whereas the strains with complete genomes containing 1991,1992,1995 and 1996 nucleotides lay in genotype B.The six DuCV strains from Cherry Valley ducks were divided into the two groups.The results of the study provides some insight into the variation of DuCVs in Cherry Valley ducks.
ABSTRACT
Objective: To explore the relation of psychological abuse and neglect in childhood and college students’ mental health. Methods: Cluster sampling was used to select 457 college students studying in the Central South University and Hunan Commercial College as subjects. The general information questionnaire,Child Psychological Abuse and Neglect Scale (CPANS) and Symptom Checklist 90 (SCL-90) were completed by all subjects. Results: 45.30% of the respondents experienced psychological abuse or neglect in childhood. The total score and scores of each factor of SCL-90 of the group of psychological abuse combined with neglect was above those of psychological-abuse group,neglect-group and neither-abuse-nor-neglect-group. Additionally,ten factor scores and total score of SCL-90 of neglect-group were distinctly higher than those of neither-abuse-nor-neglect-group. The scores of each aspect and sub-scale of CPANS were significantly correlated with every factor and total score of SCL-90(P