Detection and genetic evolution analysis of porcine parvovirus type 7 (PPV7) in Fujian Province.

Porcine parvovirus (PPV) is an important pathogen causing reproductive disorders in sows, with clinical symptoms including stillbirth, mummified fetuses, embryonic dysplasia and death, and sow infertility. Porcine parvovirus 7 (PPV7) is a recently discovered type of PPV and its widespread distribution and rapid evolution has caused huge economic losses in the pig industry. To investigate the molecular epidemiology of PPV7 in Fujian Province, China, we collected 491 blood samples and 72 tissue samples from diseased pigs in large-scale pig farms across selected areas of Fujian Province from 2019 to 2022. PPV7 infection was determined using real-time quantitative PCR, and positive samples underwent whole-genome amplification, sequencing, and subsequent homology, phylogenetic, and recombination analyses. The PPV7 positive detection rate was 25.73% (145/563) in Fujian Province, among which the positive rate of blood and tissue samples was 26.47% (130/491) and 20.83% (15/72), respectively. The nucleotide sequence homology among the 29 PPV7 whole-genome sequences obtained in this study was 90.0%-97.2%, whereas that with 128 reference strains from China and other countries was 88.9%-98.1%. Six strains had partial nucleotide deletions or insertions. Phylogenetic analysis based on the whole-genome sequences classified the 29 PPV7 strains and 128 reference strains into eight subtypes (PPV7a-PPV7h), and PPV7h was the predominant subtype in Fujian Province. Recombination analysis revealed evidence of inferred recombination events in the genomes of four strains. This study provides significant insights into the molecular characteristics of PPV7 in Fujian Province and serves as a crucial foundation for further advancements in PPV7 prevention and control strategies.

Relationship between physical activity screen time and sleep duration and overweight and obesity among children and adolescents in Beijing Tianjin Hebei region / 中国学校卫生

Objective@#To investigate the relationship among physical activity, sleep duration and screen time and overweight and obesity among children and adolescents in Beijing Tianjin Hebei region, and to provide reference for children and adolescents in Beijing Tianjin Hebei region to maintain healthy physique.@*Methods@#In November 2019, 4 262 primary and secondary school students in Beijing Tianjin Hebei region were surveyed on physical activity, sleep status and screen time according to the physical activity guidelines for children and adolescents, and the relationship between overweight and obesity was analyzed by Logistic regression.@*Results@#The prevalence of overweight and obesity among children and adolescents in Beijing Tianjin Hebei region was 22.03%. The positive rate of overweight was 12.01% and obesity was 10.02%. The prevalence of overweight and obesity in male students (26.09%) was higher than that in female students (17.88%), the difference was statistically significant ( χ 2=41.77, P < 0.01 ). The prevalence of overweight and obesity in urban children (24.09%) and Han children (22.74%) was significantly higher than that in rural areas (21.05%) and ethnic minorities (17.70%) ( χ 2=5.00, 7.63, P <0.05). The proportion of children who met physical activity, screen time and sleep duration guideline was 24.85%, 38.69% and 57.09%, respectively. A total of 21.68% of children and adolescents did not meet the guideline of physical activity, screen time and sleep duration, among which 42.80% and 28.77% met the guideline for one or two out of three behaviors, respectively. Only 6.76% of children and adolescents met the guideline of all three behaviors. Logistic regression analysis showed that the risk of overweight and obesity was negatively correlated with sleep duration ( OR=0.72, 95%CI =0.52-0.98). The risk of overweight and obesity was lower in patients with 2 criteria than in those with less sleep duration and less screen time ( OR=0.57, 95%CI =0.36-0.87).@*Conclusion@#Percentage of sufficient physical activity among children and adolescents in Beijing Tianjin Hebei region is low, and ensuring sufficient sleep duration is helpful for overweight and obesity prevention. The impact of sleep duration and screen time on overweight and obesity in children and adolescents should be considered in childhood obesity prevention and control.