Objective To investigate the species, composition and infection with Yersinia pestis of parasitical fleas on Myospalax aspalax bodies and their role in the epidemic of rodent plague in Hebei province, providing a scientific basis for the better control of rodent plague. Methods Parasitical fleas on the bodies of M. aspalax were collected and classified with Y. pestis isolated. Results Nine species of fleas belonging to 7 genera and 3 families were found in the present study. No Y. pestis was isolated from the 111 M. aspalax and the cultures of 715 fleas in 68 groups by microbiological tests, with the Y. pestis specific antibody negative in 88 serum samples from M. aspalax. Conclusion There are a great number of fleas on the body of M. aspalax that can be infected with Y. pestis naturally, with Amphipsylla daea being the dominant parasitical flea, which may be involved in plague epidemics.

Objective To identify palatable baits for Myospalax aspalax for the basis of poisonous baits during the pairing season. Methods M. aspalax were fed with different baits such as carrots, potatoes, sweet potatoes, corns, peanuts and naked oats in laboratory for comparison of palatability. Results The palatability index of carrots to potatoes, sweet potatoes, corns, peanuts and naked oats were 0.65, 0.36, 0.39, 0.25 and 0.44 when feeding alone, and 0.50, 0.90, 0.01, 0.21 and 0.13 when group feeding, respectively. Carrots were the best bait, followed by potatoes and sweet potatoes, while corns, peanuts and naked oats were of poor palatability. Conclusion Carrots, potatoes and sweet potatoes are good ingredients for the preparation of poisonous baits for killing M. aspalax.

Objective To evaluate the killing effect of aluminum phosphide and bromadiolone bait on Spermophilus dauricus, and compare the two agents in terms of their killing effect on rodents. Methods All rat holes in the experimental area were plugged before the experiment. Based on calculation of the effective holes the next day, rodentcidal agents were put in the holes, with protection zones set up between and around each of the plots. Results The killing effect of aluminum phosphide was good each month of the study, with maximum corrected efficacy rate greater than 90%. The killing effect of 0.005% bromadiolone bait was better in May to June than in July to September, with the corrected efficacy rates being more than 90% and less than 75%, respectively. Conclusion Aluminum phosphide has a strong killing effect on S. dauricus the entire active season, while 0.005% bromadiolone bait shows good efficacy against the rodent only in May and June.

【Abstract】 Carry out the plague prevention and control measures, increase the emergency handing ability of professionals, prevent and control effectively the occurrence of plague and assure the public health security of country according to the epidemic situation of plague in Hebei province trend and its geographic position by making the plague integrated control measure, publicizing the knowledge of killing rats, the evaluation of control efficacy, professionals training and actual simulated training.

Objective In order to make tracks for infectious factors of hemorrhagic fever with renal syndrome(HFRS),and to investigate hantavirus(HV) infection of rodents from urban district of Beijing. Methods We trapped the rodents in different niches in urban district monthly during 2003-2004,detected the IgG reacting sera to HV antigen using ELISA,and amplified the partial M segment of HV from captured rodent lung samples with RT-PCR and then sequenced it directly. The alignment of the nucleotide and the deduced amino acid sequences,together with phylogenetic analysis were made with DNASTAR software. Results 2 species ( Rattus norvegicus and Mus musculus) of 229 rodents were captured. The overall seroprevalence of HV infection was 4.37% (10/229) with R.norvegicus 3.51%( 6/171) and M.musculus 6.90%( 4/58) respectively. RT-PCR positive rates were 0.87%( 2/229) with R.norvegicus 0.58%( 1/171) and M.musculus 1.72%( 1/58) respectively. The nucleotide sequences of 356 bp region (1958-2313) of M segment obtained from these 2 samples were all identified to SEOV,with 5.40% divergence. Phylogenetic analysis revealed that they all belonged to Z37 subgenotypes from Zhejiang province,and could be branched into 2 different subclades. Conclusion It showed SEOV were the dominant genotypes in Murinae rodents from urban district of Beijing and had the variational nature among different hosts. The HV prevalence of hosts in urban district was not high. Besides R.norvegicus,the increasing prevalence effect of M.musculus should be noticed.

Objective To study the natural infection of spotted fever group rickettsia (SFGR) in rodents,and to compare the difference of the positive rates between different species of the southern and northern areas in China. Methods Rodents were collected in Heilongjiang,Inner Mongolia Autonomous Region,Xinjiang Autonomous Region,Zhejiang and Guizhou provinces. SFGR DNA sequence fragments in spleen of rodents was detected by PCR assay. Results The total number of 473 rodents were collected and detected,the positive rate was 14.6%. The positive samples came from Heilongjiang,Inner Mongolia Autonomous Region,Xinjiang Autonomous Region,Zhejiang and Guizhou provinces,with the infection rates of 3.1%,21.6%,30.0%,10.8%,21.4%,respectively. Conclusion There are SFGR infections in the rodents of Heilongjiang,Inner Mongolia Autonomous Region,Xinjiang Autonomous Region,Zhejiang and Guizhou province in China. The difference of the infections rates of both northern and southern areas are not significant( P> 0.05).

Objective To understand the association between the genetic variation of hantavirus and genetic differentiation of Rattus norvegicus population from Beijing.Methods The partial M segment of hantaviruses from captured rodent lung samples were amplified and then sequenced.The alignment of the nucleotide and phylogenetic analysis were made with DNASTAR software.RAPD-PCR was used to analyze the DNA polymorphism of R.norvegicus populations.Results(The 356) bp M segment obtained from 11 representative samples were all identified as SEOV,with some degree of heterogeneity(0.1%8.0%) between the different geographical locations.Phylogenetic analysis revealed that there exists at least 2 genetical distinct hantaviruses lineages.BjFT01 strain virus represented a mono-phylogentic lineage.62 clear polymorphic bands received with 4 out of 50 random primers presented the polymorphism.The cluster of analysis showed that the samples can be divided in to different groups.The individual(XFD population) from Fengtai district 2 had a special band and formed a distinct cluster.The inheritic distance of XFD population was larger than between others and was relatively independent group.Comparison of phylogenies inferred from HV and hosts showed the match phylogenies of BjFT01 strain and XFD population.Conclusion(RAPD marker) reveals the population differentiation of R.norvegicus and has some to extend association with HV variation and distribution at in Beijing.These data suggest that BjFT01 HV and their rodents hosts population share the common differentiation history.It's farther approved that Beijing Seoul virus is more probability to be transmitted from other place with the rat hosts.

Objective To identify the spatial distribution of rodents and hantavirus infection in Beijing.Methods Nine sites in Beijng were selected for a survey of HV reservoirs,especially the rodents.The captured hosts were identified.RT PCR was used to amplify the partial M fragments of hantavirus to determine the positive rate.The character of spatial distribution of hantavirus infection of rodents population was analyzed using SPSS software.Results 387 rodents were captured,among which Rattus norvegicus was the dominant species.The significant difference of spatial distribution of HV reserviors community and HV prevalence in selected sites had not been observed.The infection of SEO HV was widely distributed in the area studied,and mainly restricted to Rattus norvegicus and Mus musculus.The results of present study show that rodents from non domestic habitat did not carry HV.There was no significant difference of HV prevalence among sites as well as among 9 different niche.Significant difference in infection rate of HV was observed between domestic habitat and field habitat(include cultivation,brushwood and forest).Conclusion There are to a certain extend differences of rodents community and HV infection among different sites and different habitat in Beijing.The SEO HV infection of rodents was widely distributed in domestic habitat in Beijing and the major host of hantaviruse in Beijing was Rattus norvegicus.The new nature focus of HTN HV was not found.

Objective To investigate the species and composing of parasitical fleas of Allactaga sibirica in plague natural foci of Hebei Province.Methods Living Allactaga sibirica were collected with nest and placed in fuming-mouse tank full of aether,chloroform or petrol,rats and fleas were fumed to death without exception.Then parasitical fleas of Allactaga sibirica were identified under microspcope.Results A total of 3 families 7 genera 12 species parasitical fleas of Allactaga sibirica were discovered.The Ophthalmopsylla praefecta praefecta was most common dominant species of the parasitical fleas account for 36.6%,and Frontopsylla luculentaparilis,Ophthalmopsylla kukuschkini,Leptopsylla Pavlovskii and Frontopsylla are 9.68%,8.81%,8.72% and 7.91% respctively.Conclusion It is made clearly that the species,composition and seasonal fluctuation of parasitical fleas of Allactaga sibirica in Hebei natural foci.It provided scientific basis for further studying the prevalence factors of rodent plague and natural plague foci in Hebei province.