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Objective To group and characterize natural plague foci in China.Methods A novel two-class typing method as well as a three-indication nomenclature method were established to group and characterize the natural plague foci,on the basis of eco-geographical landscapes of plague foci,genetics of Yersinia pestis,zoology of rodent reservoirs and the entomology of flea vectors.Results A total of 12 distinct natural plague foci (including 19 subtypes) as well as their biological features were characterized.Conclusion Natural plague foci in China were grouped and characterized in this study.
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Objective To characterize the biological characteristics of natural vectors of Yesinia (Y.) pestis in China.Methods Species and genera of natural vectors of Y.pestis in China and their faunal distribution were characterized with modem insect taxonomic techniques.The ecological roles of natural vectors of Y.pestis in natural plague foci were determined according to insect ecological experiments.Results There were 63 species of natural vectors of Y.pestis including 28 major reservoirs and 35 secondary ones.Conclusion The biology characteristics of major vectors on Y.pestis and their roles in natural plague foci were defined.
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Objective To explore the relationship between wild rodent plague and human in wild rodent plague foci of the northwestern area in Yunnan to probe the possible transmission mechanism of wild rodent plague to human. Methods Data of component ratio of rodents and fleas was collected in different areas from 1985 - 1995. Activities and habits of residents regarding the way they keep cats and dogs and parasitic fleas and free fleas indoor were investigated, the dog serum was collected for detecting F1 antibody. Results Eothenomys miletus were main rodents in farmland and shrub, accounting for 48.00% (4753/9902) and 54.50% (4282/7857), Apodemus chevrieri were main rodents in garden, being 50.47% (1332/2639). The component ratio of Neopsylla specialis specialis was 13.31%(229/1720), 12.31%(1678/13 739) and 10.87%(957/8802) respectively in garden, farmland and shrub, higher than in indoor. The component ratio of Frantcpsylla spodix was 39.88% (686/1720), the highest in garden. Thirty-two per cent (32/100) of residents kept cats,in which 63% (20/32) with cat fleas, 68% (68/100) of villages kept dogs, in which 76%(52/68) with fleas. Eighteen parasitic fleas were caught from 43 dogs with a flea index of 0.119 and a rate for fleas of 11.63%, 7 pulex were collected from 17 indoor. Forty-three blood serum samples were obtained from dogs, among which 3 were positive blood serum. Conclusions Residents touch affected animals or media in different situations. The possibility of transmission for wild rodent plague to human exists in loci in a chain of wild rodent plague → fleas or predation → homebred animal plague (cats or dogs) →touching or respiratory → human.
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<p><b>OBJECTIVE</b>To investigate the prevalence of Anaplasma phagocytophilum in small mammals from the forest area of Hengduan Mountains in southwestern China.</p><p><b>METHODS</b>Small mammals captured from Gaoligong and Xianggelila mountainous area of Yunnan province were detected by PCR amplification. The sequences of 16S rRNA and Msp4 gene fragments from positive samples were compared with corresponding sequences deposited in GenBank.</p><p><b>RESULTS</b>A total number of 436 small animals, which belongs to 5 orders 18 genera 35 species were tested, 32 (7.34%) were positive in 6 genera 11 species. There were 8.64% (26/301) positive in 25 species at Goligong mountainous areas, and 4.44% (6/135) were positive in 19 species at the Xianggelila mountainous areas. Positive small mammals were most rodents. The nucleotide sequences of A.phagocytophilum 16S rRNA gene amplified from small mammals varied from 99% - 100% and were 99% - 100% similar with the corresponding segments of A. phagocytophilum from Jilin deposited in GeneBank. The sequences of A. phagocytophilum Msp4 gene showed that there was 95% - 97% similarity with the corresponding sequences registered in GenBank.</p><p><b>CONCLUSION</b>A. phagocytophilum was firstly identified in 6 genera 11 species small mammals from a forest area of Hengduan Mountainous areas in southwestern China. Rodents might serve as the primary hosts indicating the potential risk to the domestic animals and human beings in this area.</p>
Subject(s)
Animals , Anaplasma phagocytophilum , Classification , Genetics , Base Sequence , China , Epidemiology , DNA, Bacterial , Genetics , Ehrlichiosis , Epidemiology , Molecular Sequence Data , RNA, Ribosomal, 16S , Genetics , Rodentia , Microbiology , Sequence Analysis, DNAABSTRACT
<p><b>OBJECTIVE</b>To investigate Bartonella infections in small mammalian reservoir hosts from different environments and types of climate in Yunnan.</p><p><b>METHODS</b>Femoral blood samples were collected from the anesthetic captured animals from five counties including three types of climate. All isolates were grown on brain and heart infusion agar plates containing 5% defibrinated rabbit blood. The agar plates were incubated at 35 degrees C in a humidified with 5% CO2 environment for at least 4 weeks. Bartonella-like isolates were confirmed by the polymerase chain reaction and visualizing the target gene fragment by gel electrophoresis.</p><p><b>RESULTS</b>Bartonella species were isolated from 69 of 176 small animals including 4 species of 3 genera from 4 counties and the total prevalence in rodents was 39.2%. The maximal prevalence was 42.0% of Rattus tanezumi flavipectus usually inhabiting indoors and courtyard and contacting closely to human. Moreover, Bartonella isolates were obtained from Rattus noruegicus, Eothenomys miletus and Mus pahari. Life environments of captured animals involved indoors, courtyard, brush and forest in mountain.</p><p><b>CONCLUSION</b>The finding in this study suggested the characteristic of diversity of Bartonella infections in rodent hosts in southern China included Bartonella species parasiting in a wide range of animal hosts in different environments as well as climate types. Further investigations were needed in different areas in China to confirm more mammalian reservoir hosts with Bartonella infections.</p>