RESUMEN
Senecaviurs A (SVA) infection, an emerging infectious disease in pig populations, is characterized by vesicular lesions predominantly affecting the mouth, snout, and hooves of infected pigs, similar to the symptoms of Foot and Mouth Disease Virus (FMDV). This disease first spread into China in 2015, causing great panic in the pig breeding industry. To determine the prevalence of SVA in pig herds in China from 2018 to 2021, a total of 4,901 pig tissue samples were collected from 18 provinces, autonomous regions and municipalities (P.A.M.s) for epidemiological investigation, virus isolation and genetic analysis. In 2021, the individual positive rates (IPRs) from the perspective of spatial distribution in East China, South China, Central China, North China, Southwest China, Northwest China, and Northeast China were 0, 0, 1.69, 0.94, 11.70, 3.31 and 2.21%, respectively. The herd positive rates (HPRs) were 0, 0, 9.52, 9.09, 50.00, 7.69 and 23.08%. From the perspective of temporal distribution, the IPR showed an overall downwards trend from 2018 to 2021, with only a slight increase in 2020. Moreover, the HPR decreased from 36.63 to 10.07%. From the perspective of population distribution in 2021, the IPR (2.62%) and HPR (12.00%) in apparently healthy pig herds (slaughterhouses) were greater than those in non-healthy pig herds (2.10 and 5.13%, respectively), consistent with the results in 2019. To characterize the prevalent strains, 10 SVA strains isolated from positive samples in 2019 were clustered in Clades I and VII; SVA-FJ039-2019, SVA-HuN032-2019, SVA-GX011-2019, SVA-FJ036-2019, SVA-GXF011-2019 and SVA-GXF053-2019 were clustered in Clade I; and SVA-FJ018-2019, SVA-SD069-2019, SVA-SD072-2019, and SVA-SD074-2019 were clustered in Clade VII. In conclusion, until 2021, the prevalence of SVA in pig herds in China was still relatively high, the contaminated area was still large, and there were a number of hidden infections. In the future, the epidemic status of SVA in pig herds in China must be closely monitored and the prevention and control measures must be adjusted in a timely manner.
RESUMEN
In this study, a total of 3432 aquatic animals covering eight species were tested by specific polymerase chain reaction (PCR) assays to investigate the presence of Toxoplasma gondii, in China. The results showed that, out of 618 Procambarus clarkii samples collected from the different areas in southeast China, four samples from Jiangxi province were positive. Of 456 Hypophthalmichthys molitrix samples, one sample from Jiangsu province was positive. In addition, there was only one positive sample collected from Shandong province out of 813 Macrobranchium nipponense samples. All other samples, including 309 Cyprinus carpio, 398 Concha Ostreae, 98 Momopterus albus, 426 Penaeus monodon Fabricius and 309 Carassius auratus were negative. The results suggested that the level of T. gondii in aquatic animals was low in China. However, the importance of T. gondii in aquatic animals should not be ignored. Consumption of contaminated raw shellfish may represent a considerable health threat.
