To gain a better understanding of the genetic diversity and evolution of PRRSV in the Ningxia Hui Nationality Autonomous Region (Ningxia) of China, the nsp2 genes from a series of PRRSV strains collected from the region in 2007 were partially sequenced. These sequences were then analyzed along with the classical strain (ch-la) and two other epidemic strains SD (3) and SD2006. Comparison of the nucleotide sequence with ch-la indicated that nsp2 genes of seventeen Ningxia isolates (NX strain) have deletions of 87 nucleotides. Sequence analysis indicated that homology between the Ningxia strain and ch-la was 60.3%-79.9% in the nucleotide sequence, and homology between the NX strains and SD strains was 80.3%-98.8% in the nucleotide sequence. The nsp2 genes of the seventeen isolates had 74.9%-100% nucleotide sequence identities with each other. This study was undertaken to assess the regional variation of prevalent PRRSV and to establish a sequence database for PRRSV molecular epidemiological studies.

In order to explore the role of pre-basic course teaching in the standardized training of residents in clinical pathology, we have independently designed and constructed a pre-basic course teaching system mainly focusing on anatomy and histoembryology, consisting of two levels of theoretical teaching (small lectures by students and systematic lectures by instructors) and two dimensions of practical training (sample collection teaching and case teaching). This teaching model centering on participatory lecturing, practice, summarization, assessment, and feedback has been demonstrated effective. The results showed that the theoretical and practical assessment scores of the experimental group [(458.80±17.60) and (415.40±19.30), respectively] were significantly higher than those of the control group [(444.50±20.90) and (398.80±23.70), respectively]. Among 28 students of grades 2019 to 2021 surveyed for teaching effectiveness, 96.43% were satisfied with the teaching model. The established teaching model provides new ideas for the reform of teaching methods in the standardized training of residents in clinical pathology.