Epidemiological surveillance and typing of Leptospira strains in rodents in Hunan Province during 2020-2022
To investigate the epidemiology and conduct etiological characterization of pathogenic Leptospira,we trapped 461 rodents and soricidae belonging to seven species in four regions with leptospirosis cases in Hunan province during 2020-2022.The density of rodents was 2.52%,and the most prevalent rodent species in these four regions was Apodemus agrarius.A total of 56 pathogenic Leptospira isolates from Apodemus agrarius,Rattus flavipectus and Sorex araneus Linnaeus were successfully isolated;the isolation rate in rodents was 12.15%.Microscopic agglutination tests(MATs)with 15 Chinese stand-ard serogroup-specific rabbit antisera were conducted for serogroup identification.Multilocus sequence typing(MLST)based on seven loci(glmU,pntA,sucA,tpiA,pfkB,mreA and caiB)was performed for genotyping.Two serogroups were identified among the 56 Leptospira isolates.Icterohaemorrhagiae was the dominate serogroup,accounting for 94.64%.Three se-quence types(STs),ST1,ST128 and ST105,were identified through MLST analysis.ST1(57.14%)and ST128(37.50%)were the dominant STs in Hunan.Phylogenetic analysis using UPGMA in BioNumerics software version 5.1 identified three clades(clades 1-3)corresponding to three different STs a-mong the 56 pathogenic Leptospira isolates.The leptospiral diversity of STs differed across animal species and regions in Hunan.Icterohaemorrhagiae was the main serogroup;and ST1 and ST128 were the main STs in Hunan.The epidemiology of rodents and the detailed serological and molecular characteristics of strains circulating in this province may aid in developing strategies or guidelines for vaccine preparation and the control of leptospirosis in Hunan.