Objective The purpose of this study was to investigate the reproductive characteristics of indoor-housed Meriones meridianus.Methods According to the data of Meriones meridianus from 1996 to 2002 in the Center for Laboratory Animal research of Xinjiang, the sexual maturity period of male and female animals, the gestation period of female animals, the litter size, weaning rate, survival rate, sex ratio per month and different fetal times were statistically analyzed.Results Sexual maturity period of male and female animals was 109.3 ±21.0 days and 106.3 ±21.7 days, and gestation period of female animals was 21.3 ±1.4 days.The litter size, weaning rate of different fetal times showed no significant difference compared between those of the first to seventh litter ( P>0.05) , and the survival rate of fourth and sixth litter were lower than that of the average offspring per litter, but the difference was no significant (P>0.05).The sex ratio of from first to sixth litter indicated no significant difference ( P>0.05 ) , and the average proportion of male and female was 1.4:1.0.During a year, the animals almost stopped to reproduce from September to November, however, the differences of litter size between the other months were statistically not significant ( P >0.05 ) , the weaning rate and survival rate per month suggested a significant difference ( P <0.05 ) between some of the months.Conclusions Compared with the background data of wild Meriones meridianus, the laboratory reproduction of Meriones meridianus show some differences, mainly, the season of breeding is shifted to December, and the number of reproduction increased by one or two litters.Our results provide useful reference for laboratory animalization of Meriones meridianus.

Objective To observe the dynamics of F1 antibody and immunoglobulin M (IgM) in cats after vaccinated Yersinia pestis,to discuss the significance of detection of F1 antibody and IgM in surveillance of animal plague.Methods The 3 cats were vaccinated Yersinia pestis on their backs with muhipoint hypodermic injection and blood samples were collected via femoral vein on 3rd to 521st days after injection.F1 antibody was detected by sandwich Enzyme-linked immunosorbent assay (ELISA),and IgM of F1 antibody was determined with a capture antibody.Results After vaccinated Yersinia pestis for 3rd days,F1 antibody and IgM appeared slightly positive,with the titer of 1 ∶ 22.00 and 1 ∶ 20.33,respectively.The titer of F1 antibody increased to 1 ∶ 25.33 on the 4th day,and reached the peak of 1 ∶ 29.67 on the 97th day,kept 1 ∶ 25.33 on the 521st day.While the titer of IgM reached peak of 1 ∶ 212.00 on the 7th to 10th days,and decreased rapidly to below the positive standard on the 30th day.Conclusions Detection of F1 antibody in cats with plague by sandwich ELISA can trace plague prevalence in animals back to a long time,which may be applied for investigation of plague foci.A single serum sample can determine early animal plague with a capture antibody to detect IgM of F1 antibody in cat with the plague,and a single serum sample tested with the two methods at the same time for detection of F1 antibody and IgM can precisely verify the infection time of plague in animals for 3 to 7 days.

Objective To conduct morphological observation and gene identification of the strain of flagellate iso -lated from Cricetulus migratorius in the Xinjiang Research Center for Experimental Animals .Methods The ileocecal con-tents of C.migratorius were microscopically examined on direct smear with Wright-Giemsa staining , and the total RNA iso-lated from Xinjiang C.migratorius was extracted and 16S rRNA was amplified by PCR , and then sequenced .Furthermore the homology was compared and the phylogenetic tree was developed using MEGA 5.22 software.Results Morphological observation indicated that the isolated flagellate was Tritrichomonas muris.The 16S rRNA gene sequence of the Xinjiang C. migratorius isolate shared highly homology with that of other Tritrichomonas.Phylogenetic tree analysis indicated that the 16S rRNA gene of Xinjiang C.migratorius isolate was classified into a subgroup with T.muris 16S rRNA (U85966.1), but was relatively distant relative from other related tritrichomonas.Conclusions The flagellate isolated from Xinjiang C. migratorius is identified to be T.muris by both morphological observation and 16S rRNA gene analysis.

ObjectiveTo determine the virulence of desert-type Leishmania donovani strains through animal infection experiments and to explore preservation methods for maintaining their pathogenicity.Methods The isolated strain was cultured in vitro for 7, 30, 36, 44, 60, 90, and 150 days, respectively， and inoculated into Lagurus lagurus (L.lagurus) with the dose of 2.6×10⁵ per animal by intraperitoneal injection. The spleen coefficient, infection rate, and antibody positive rate of the inoculated animals were detected at day 60 after infection. The desert-type Leishmania donovani strain was further inoculated with Cricetulus migratorius (C.migratorius) and L. lagurus, respectively, for passaging and preservation. The survival time of two kinds of animals andpathogenicity change of the stain in their bodies were compared.ResultsAfter inoculation of desert-type Leishmania donovani strains cultured in vitro for 7-150 days, the spleen coefficient of inoculated L.lagurus gradually increased from 1% on day 7 to 2.2% on day 30, which was more than 10 times of the normal spleen coefficient. Additionally, on day 60, the spleen coefficient remained 3 times higher than the normal value. The infection rate and antibody positive rate decreased from 80% on day 7 to 0% on day 60. At 90 days, there were no significant differences between the infected groups and the control group, and all the observed indexes were within the normal range. The survival time of L.lagurus infected with the in vivo passage strain ranged from 1 to 13 months, and half of the infected individuals died within 4 months. In contrast, C.migratorius had a survival time ranging from 5 to 31 months, and half of the infected individuals died within an average of 13.7 months. There was a significant difference in the average time of death between the two groups (t=0.000 1, P<0.001), but no significant difference in spleen coefficient (t=0.990, P>0.05). This strain exhibited equal virulence in both animals and remained virulent for up to 4 years after continuous passage.ConclusionWith the prolonged culture time, the virulence of the strain decreases gradually. At 90 d, it has no pathogenicity to L. lagurus. Long-term in vitro culture fails to preserve it's pathogenicity to L.lagurus. Only in vivo inoculation can maintain the virulence of this strain.