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Objective: To investigate the prevalence of Echinococcus infections in wild carnivores in Serthar County, Sichuan Province, so as to provide insights into echinococcosis control in local areas., Methods: Stool samples were collected from wild carnivores in Serthar County, Sichuan Province in May 2021, and the host sources of stool samples and Echinococcus infections were identified using PCR assays. The prevalence of E. multilocularis , E. granulosus and E. shiquicus infections was estimated in different hosts., Results: A total of 583 stool samples were collected from wild carnivores, including 147 stool samples from fox, 154 from wolf, 227 from wild dogs and 11 from lynx. The overall prevalence of E. multilocularis , E. granulosus and E. shiquicus infections was 5.68%, 0.19% and 14.20% in canine stool samples, and no E. granulosus infection was detected in fox stool samples, while the prevalence of E. multilocularis and E. shiquicus infections was 0.68% and 47.62% in fox stool samples (χ 2 = 88.41, P < 0.001). No E. granulosus or E. shiquicus infection was detected in wolf stool samples, and the prevalence of E. multilocularis infection was 10.39% in wolf stool samples. The prevalence of E. multilocularis , E. granulosus and E. shiquicus infections was 5.73%, 0.44% and 2.20% in canine stool samples (χ 2 = 12.13, P < 0.01). In addition, the prevalence of E. multilocularis infections was significantly higher in wolf stool samples than in canine and fox stool samples (χ 2 = 13.23, P < 0.01), and the prevalence of E. shiquicus infections was significantly higher in fox stool samples than in canine and wolf stool samples (χ 2 = 187.01, P < 0.001). No Echinococcus infection was identified in 11 lynx stool samples., Conclusions: The prevalence of Echinococcus infections is high in wild canines in Serthar County, Sichuan Province. Wolf, wild dog and fox all participate in the wild life cycle of E. multilocularis in Serthar County, and wolf and wild dogs may play a more important role.

145 strains Gardnerella vaginalis isolated in foxes were isolated from 13 main farms raising foxes in six provinces (regions), China, after antigenicity and immunogenicity of the strains were measured, 1-3 appropriate strains were selected from each farm raising foxes for serotype studies. Cross agglutinin absorption test confirmed that selected 26 strains Gardnerella vaginalis were divided into three serotypes and then the representing strains were used to produce typing serum. Among remaining 119 strain, 108 strains were typable with the typing sera, and 11 strains can't be set. Among three serotypes, serotype I made up 79.1% of the strains. It was shown that serotype I was the principal serotype of Gardnerella vaginalis of fox in China. The test also confirmed that 5 strains of Gardnerella vaginalis isolated from racoon dog, 4 strain Gardnerella vaginalis from mink and 2 strains Gardnerella vaginalis from canine also belonged to serotype I. Supersonic antigben was produced with three serotypes, representative strains. By agar immuno-diffusion test, it confirmed that the antigens of three serotypes formed a obvious blending precipitating line with the homologous or heterologous serotype antiserum. It indicated common antigen existed among all serotypes. The agar immuno-diffusion test results revealed that the precipitating line of the homologous serotype completely blended. It is our opinion that the method of serotyping is reliable.

192 Gardnerella vaginalis antibody positive sera from artifically infected foxes, immunized foxes and foxes that the bacterial examination were positive were analysed by the established Dot-ELISA. The results showed that 187/192 were positive, the positive rate was 97.3%. Block and cross tests showed that the method was specific. The method was 28.1 times sensitive as PAT and 5.5 times sensitive as MAT respectively. The repeatability of the test was good and the positive coincidence rate among the three techniques was 100%.

By epidemiological investigation to Gardnerella vaginalis disease of fox of civil main farms raising foxes, this disease was showed to be susceptible to silver foxes, arctic foxes, red foxes and color foxes, the disease was mostly transmitted by copulation, infected foxes played the leading role in epidemic of the disease. Investigative results of all farms raising foxes showed infection rate of fox groups was 0.9-21.9%, resulting in abortion rate was 1.5-14.7%, empty rate was 3.2-47.5%. Serious harm was revealed to the disease. By serology and causative agent isolation, we had proved that the disease was able to infect feeder and manager, it belongs to zoonosis. Racoondog. mink and canine infect with the disease besides fox. White mouse, big white rat, gopher, guinea pig and rabbit for laboratory are not infected with the disease.

16 strains isolated from aborted foetus and vaginal exeretions of foxes were used for examination of cell morphology including fine structure of the cell wall and septa, test for homolysis, biochemical reactions and analysis of G+C content of the bacterial DNA. The cells are pleomorphic bacilli and coccobacilli, Gram stain reaction appear positive to variable, catalse and oxidase-negative, with a fermentative type of glucose metabolism, giving acetic and lactic acid as the major end products of fermentation. It's differentiated from the human strains of G. vaginalis by its less fastidious in growth requirements and being facultatively anaerobic to aerobic. We propose the name: a new subspecies--Gardnerella vaginalis subsp. fox, the type strain is U80.

It is the first time that this paper reports on using improved rabbit blood agar culture medium to isolate 145 strains Gardnerella vaginalis from the foxes and their abortion fortus organs of main fox farms. Among the strains, 26 strains were isolated from the abortion foetus organs, isolation rate was 92.86%; 118 strains were isolated from the vaginal exeretion of the abortion and empty foxes, isolation rate was 34.01%; 1 strain was isolated from inguinal lymph node of the pelted positive fox, isolation rate was 2%. None was isolated from blood. By causative agent isolation, we revealed the bacterium survival position in vivo, and the best isolation route isolation opportunity and isolation methods were selected. By artificial infection test, we have proved pathogenicity of the bacterium.