Objective To analyze the epidemic characteristics of plague epidemics, host and vector community structure, and abundance in plague focus of wild rodents in Yunnan Province, 2017-2023, providing a scientific basis for formulating plague prevention strategies and forecasting warning for this epidemic foci. Methods　Following the requirements of the "National Plague Surveillance Plan" and the "Yunnan Provincial Plague Surveillance Plan", host-vector surveillance, etiology, and serological testing were carried out, and plague epidemic data and host-vector surveillance data in plague focus of wild rodents in Yunnan Province, 2017-2023 were collected and sorted using Excel 2019 software to create a database for descriptive analysis. Results From 2017 to 2023, 11 animal plague epidemics were discovered in the wild plague foci of Yunnan Province, with 18 epidemic spots. From the altitude distribution point of view, 7 epidemic spots were distributed at an altitude of 2 800-3 000 meters, another seven at 3 000 and 3 200 meters, and four spots were located in areas with an altitude of ≥3 200 meters; a total of 36 samples of host and vector animals were detected positive, including 28 positive samples of host animals and 8 positive samples of vector animals, and 29 strains of Yersinia pestis were isolated; in terms of species composition, Eothenomys miletus accounted for the largest proportion of 41.67%, followed by Apodemus chevrieri at 22.22%; Ctenophthalmus quadratus at 11.11%; Rattus tanezumi and Neopsylla specialis each at 8.33%, and Dremomys pernyi, rat carcass, and Frontopsyllas padix each accounted for 2.78%; the epidemic peaked in April, and no human cases were found. A total of 453 220 rat cages (traps) were placed, capturing 27 677 rodents, with an average capture rate of 6.11%. A total of 25 075 main hosts, Apodemus chevrieri and Eothenomys miletus, were captured, accounting for 90.60% of the total capture rate. A total of 14 700 fleas were seized on the surface of small animals, with a total flea infection rate of 23.13% and a flea index of 0.59. The main vectors were Ctenophthalmus quadratus and Neopsylla specialis, with constituting ratios of 45.71% and 22.69%, respectively. Conclusions From 2017 to 2023, the population density of main host animals in Yunnan's wild rodent plague foci was relatively high and showed an upward trend, possibly related to the local planting structures. Plague plays a regulatory role in host population structures. Epidemics among animals showed obvious seasonality, with a trend of expanding epidemic areas. No human cases were found, but Yersinia pestis was detected in Rattus tanezumi in human settlements, raising the possibility that animal plague could spread to humans. It suggests strengthening the monitoring of areas adjacent to the epidemic source, eradicating rats and fleas in spring, improving the accuracy of plague prediction and early warning, providing strong technical support for the early detection of plague among animals, and preventing the spread of the epidemic to humans.

β- N-Acetyl- D-glucosaminidase ( NAGase, EC3.2.1.52) is a composition of the chitinases and cooperates with endo-chitinase and exo-chitinase to disintegrate chitin into N-acetylglucosamine. Pacific White Shrimp (P. vannamei) NAGase is involved in digestion and molting processes. Some pollutants in seawater affect the enzyme activity causing loss of the biological function of the enzyme, which affects the exuviating shell and threatens the survival of the animal. The effects of acetic anhydride on the enzyme activity for the hydrolysis of pNP-NAG have been studied. The results show that acetic anhydride can lead to reversible non-competitive inhibition at appropriate concentrations, and the IC50 is estimated to be 9.0 mmol/L. The equilibrium constants have been determined for acetic anhydride binding with the enzyme and/or the enzymesubstrate complexes. Inhibition kinetics of acetic anhydride on the enzyme has been studied using the kinetic method of the substrate reaction. The results suggest that at pH 6.2, the action of acetic anhydride on the enzyme is first quick equilibrium binding and then slow inhibition. The microscopic rate constants have been determined for inhibition and reactivation. The results show that k + 0 is much larger than k - 0, indicating the enzyme is completely inactivated at sufficiently large modificator concentration.