Objective To prepare a polyclonal antibody against the outer membrane protein OspC and the flagellin FlaB of Borrelia burgdorferi (also called Lyme disease spirochete) after prokaryotic expression, and to test its immunogenicity. Methods The genomic DNA of B.garinii strain BgNMJW1 was used as a template to amplify the gene segments of OspC and FlaB using polymerase chain reaction (PCR); then the PCR products were subcloned into the expression vector pGEX-6p-1 and transformed into the expression strain Rosetta. The fusion proteins were expressed after induction with isopropyl thiogalactoside (IPTG) and purified using glutathione transferase (GST) column or via gel cutting. The purified proteins were then used to immunize New Zealand white rabbits to obtain polyclonal antiserum. Results The result of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that compared with the control, the vector carrying the target genes had obvious expression of recombinant proteins after induction, and the sizes of the recombinant proteins were about 49×10 ³ and 63×10 ³, respectively. The induction result showed that the expression of the induced proteins reached its peak level if 1 mmol/L IPTG was added when the bacteria were cultured to an absorbance ( A) of 0.4, followed by inducing at 25℃ for 10 hours. By immunizing New Zealand white rabbits with the purified fusion proteins, the polyclonal antiserum was obtained and used to detect OspC and Flab of B.garinii strain BgNMJW1 and B.burgdorferi strain BbB31A3 in Western blot, then the clear detection bands were obtained. Conclusion The combined application of OspC and FlaB can play an effective role in the diagnosis of Lyme disease.

Objective To identify Borrelia species in ticks collected in Gengma Dai and Va Autonomous county of Yunnan province using molecular biology detection methods, and to provide a basis for the investigation of local Lyme disease. Methods DNA was extracted from individual free-living ticks collected in Gengma county of Yunnan province in April 2016, and Borrelia DNA was identified by nested-PCR amplification of the 5S-23S rRNA intergenic spacer region. Positive samples were further tested by 16S rRNA amplification and verified with the flagellin ( FLA) gene. Results A total of 94 ticks belonging to 3 species were captured, and 14 ticks (14.89%) were positive for Borrelia. All Borrelia-positive ticks were Ixodes ovatus, and there was no significant difference in the rate of Borrelia positivity between sexes ( χ ²=0.746, P=0.388). Ixodes acutitarsus and Dermacentor auratus tested negative for Borrelia. The sequences of the three target gene fragments identified from Borrelia were 98%-99% homologous to those in B. sinica. Phylogenetic analysis showed that the bacterial species identified in this study clustered with B. sinica detected in Sichuan and Anhui provinces, China, and was close to B. japonica but distinct from B. afzelii, B. burgdorferi sensu stricto, and B. valaisiana. Conclusion Ixodes ovatus collected from Gengma county carries B. sinica. The types and distribution of hosts and vectors of B. sinica and its pathogenicity in humans warrant further investigation.

Objective To understand epidemiological characteristics of typhus, in order to provide the scientific basis for prevention and control of this disease. Methods The incidence data of typhus were collected from Disease Reporting Information System in Yunnan province in 2005-2014, and descriptive epidemiological analysis and SPSS 16.0 software were conducted on the data. Results A total of 10 712 typhus cases distributed in 106 counties (districts) of Yunnan province with an average incidence of 2.34/100 000 from 2005 to 2014, including 0 deaths. Among them, 77.03% of the cases were from Xishuangbanna prefecture with the highest incidence of 76.56/100 000 in the province. There were statistical significances among the incidence of different areas ( χ ²=2.603, P<0.05). Of these patients, 65.52% of the cases occurred in summer-autumn seasons (from June to November), 18.51% were in the group of patients aged 30-39,proportion of male and female was 1:1.44, 57.21% were farmers. There were statistical significances among the annual incidence of different occupational groups( χ ²=3.280, P<0.05). Conclusion Typhus cases in Yunnan province were mainly sporadic and primarily concentrated in Xishuangbanna prefecture, so the prevention and control measure in the key areas should be strengthened.

Objective To analyze the genetic evolution and epidemiological pattern of Hantavirus (HV) isolated from different hosts, vectors and patients in different time from different regions of southeastern China from 1980 to 2015. Methods The mutation site and frequency in S, M segment hypervariable region of HV isolated from southeastern China,including Jiangsu province, Zhejiang province, Shanghai and Fujian province, from 1980 to 2015 were detected. Combining the information of HV, hosts, vectors, environment and epidemiology, the HV evolution laws in different regions, time, natural reservoir and important vectors were analyzed. Results The HV strains isolated from the hemorrhagic fever with renal syndrome (HFRS) patients in the southeast coastal area were mainly the Hantaan virus (HTNV), which were highly homologous with the 76-118 strain. While the Seoul virus (SEOV) carried by patients exhibited the highest sequence similarity to the Z37 strain. The southeast coastal area is the mixed type of HV-affected area, with apparent endemicity. The HV isolated from the rodents shared the highest identity to SEOV. The HV clades were related to host types and the locations of sample collection. SEOV was carried primarily by Rattus norvegicus, while HTNV was carried primarily by Apodemus agrarius. Conclusion The formation and maintenance of HFRS epidemic areas show a certain regularity.

Objective To study the infection of Schistosomiasis in small mammals and other final host after achieving control standards of schistosomiasis in Eryuan, explore small mammals' roles in schistosomiasis transmission in mountainous endemic regions in Yunnan province. Methods To capture the small mammals by night trapping method in the cultivated area with snail breeding around the villages. The infection by anatomical observation and stool examination after taxonomic identification of the small mammals. The infection of Schistosomiasis of residents and domestic animals, and situation on the snails were surveyed by the routine method,2010-2011. Results Six species, 4 genera, 3 families and 3 orders of 307 small mammals were captured in the schistosomiasis area. The rate of the captured was 12.79%. The predominant species were Rattus sladeni and Apodemus chevrieri, which accounted for 53.75% and 20.85% respectively. Among 305 small mammals being tested, one R. sladeni was infected with Schistosomiasis japonica, the infection rate of R. sladeni was 0.61%(1/165) and EPG(x) was 0.291, small mammals was 0.33%(1/305)and EPG(x) was 0.157. The infection rate of Schistosomiasis of humans, cattles, horses and dogs were about 1.01%(6/597), 0.83%(5/599), 0.58% (1/173), and 5.91% (13/220), and other animals were negative. The infectiosity EPG(x) of humans, cattles, horses and dogs were 0.009-0.010, 0.005, 0.007, and 0.080. There was statistical significance between the infection rate of Schistosomiasis of small mammals and dogs (χ²=15.339, P<0.05), as small mammals with others no significant differences. Density of living snails was decreased and no infected snail was found. Conclusion The result indicated the low infection of Schistosomiasis in small mammals in the area where it was achieved with control standard of Schistosomiasis. Further investigation may need to confirm the infection of Schistosomiasis in small mammals in some areas of mountainous valley region.

Insectivorous animal is one of the oldest and most primitive mammals, which is widely distributed throughout the world. Hantavirus is one of the most important zoonotic pathogens, causing hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). In recent years, 23 types of hantaviruses have been found in insectivorous animals. The typing, phylogenetic, co-evolution or cross-species transmission of hantaviruses associated with insectivorous animals were reviewed in this paper.

Objective To analyze the sequence of Hantavirus(HV) from Zhejiang, Fujian provinces and Shanghai municipal. Methods The sequence of M segment of several HV strains from coastal areas of Zhejiang, Fujian province and Shanghai municipal were collected and analyzed by Mega 4.0 and DNAStar software, phylogenetic trees were built by neighbor joining method (NJ) and analyzed to compare the similarity of HV strains isolated from Zhejiang, Fujian provinces and Shanghai municipal. Results The phylogenetic tree revealed that the similarity of isolates in the same province is much higher than the other, meanwhile, in same province or city, the nucleotide similarity of the same region is higher than the other regions. The distributions of the isolates from closer regions share higher sequence similarity in the phylogenetic branches. The ZH53 strain of HTN isolated from Fujian province, Gou3 strain and ZJ5 strain of SEO isolated from Jiande region in Zhejiang province formed a distinct phylogenic lineage in HTNV clade and SEOV clade respectively, and these strains were different from other variants and international standard strains with the similarity of 82.7%-86.3% and 84.0%-85.3% respectively. The SEOV strains in Zhejiang were isolated from field mouse indicating the phenomenon of “host spillover”. Conclusion The sequence similarity and the phylogeny of HV in southeast costal area of Zhejiang, Fujian provinces and Shanghai is closed related to the isolated regions, indicating geographic distribution of HV.

Objective To analyze the prevalence and genotypes of Hantavirus (HV) among rodents in the epidemic areas of hemorrhagic fever with renal syndrome (HFRS) in Zhejiang province, China from 2008 to 2011. Methods Direct immunofluorescence assay and RT-PCR were used to detect the antigen and nucleic acid of HV. Mongolian gerbils and Vero-E6 cells were used to isolate viruses from the HV-positive rodents, and the M segments of HV isolates were subjected to sequence analysis. Results Apodemus agrarius was the dominant species of the rodents captured in the epidemic areas of HFRS in Zhejiang province from 2008 to 2011. Six strains of HV were isolated from the lungs of this rodent species. The sequence analysis showed that the six isolates belonged to Hantaan virus (HTNV), wherein Z521, 524, and 534 were classified as H7 subtype, and TT-27, T-43, and R88 might be classified as a new subtype. The six HV isolates showed high gene homology between them and with the strains previously isolated in Zhejiang province. Conclusion HTNV was prevalent in rodent in the epidemic areas of HFRS in Zhejiang province from 2008 to 2011.

Objective The bioactivity of the essential oils from Mosla chinensis against Aedes albopictus was determined, and the chemical composition of the essential oils was analyzed to provide the basis for development of botanical mosquito control agents. Methods The essential oils were extracted from M. chinensis using steam distillation. The bioactivity of the essential oils against 4th instar Ae. albopictus larvae and pupae was determined using immersion tests, and the repellent activity was examined using human skin tests. The gas chromatography?mass spectrometry was employed to analyze the chemical composition of the essential oils from M. chinensis. Results （1） The 24 h LC₅₀ values for 4th instar Ae. albopictus larvae and pupae were 78.820 μg/ml and 122.656 μg/ml, respectively; （2） application of 1.5 mg/cm2 pure essential oils provided (2.330±0.167) h of complete protection time against adult mosquitoes, and 56% of the protective effects remained beyond 6 h; and （3） a total of 44 compounds were detected from the essential oils and 39 were identified, accounting for 98.67%. The main components included p?cymene (23.17%), 5-isopropyl-2-methylphenol (16.83%), thymol (14.92%), Benzene, 2-methoxy-4-methyl-1-(1-methylethyl) (12.89%), eucalyptol (8.48%), caryophyllene (3.96%), α?caryophyllene (3.16%) and thymol acetate (2.71%). Conclusion The essential oils from M. chinensis had strong bioactivities on both Ae. albopictus larvae and adult mosquitoes. New natural active compounds may be found from these essential oils for development of environment?friendly mosquito control agents.

Objective Several kinds of food are preferably palatable to Oncomelania hupensis. The most effective food?based attractants were identified in this study, and the application of these attractants in molluscicidal pellets was evaluated.  Methods The attracting effects of the mixture of Sedum sarmentosum leaves (food M), and fermented cornstarch (food C) were compared under various environmental conditions with different humidity and light levels. The two were combined with the water extract of Gynostemma pentaphyllum, a molluscicidal plant, to produce molluscicidal pellets, respectively, for experiment on the snail killing effects.  Results Statistically significant differences were shown in the attracting effects of different food attractants on O. hupensis under room temperature (25 ℃).  The attracting effects were greatly humidity?dependent, as the ones under an 80% relative humidity were stronger than those under a 40% relative humidity. The multi?factor analysis of variance showed that humidity (F1，64＝60.209, P＜0.001), snail food (F3，64＝344.820, P＜0.001) and time (F3，64＝724.429, P＜0.001) had substantial impact on the attracting  effects. The  attracting  effect  of  snail  food  M  was greater than that of snail food C.  Light had little influence on attracting O. hupensis.  The molluscicidal pellets made of food M and C increased the 7 d snail mortality rates by 42.68% and 30.00% as compared  to  the  control  and  experimental  groups, respectively.  Conclusion Food M had a relatively stronger attracting effect on O. hupensis under 25 ℃ and 80% relative humidity; when added in molluscicidal agents, it greatly increased the snail mortality.

Objective To provide a preliminary evaluation of the self?made horseradish peroxidase (HRP) marked Hantavirus (HV) recombinant N protein (rNP) rNP?IgM direct capture ELISA diagnostic kit. Methods Assessment of the specificity and stability of the kit and comparison of clinical results with similar products were performed to evaluate the sensitivity of the kit in the detection of serum anti?HV?IgM. Results (1) The kit was only responsive to anti?HV?IgM positive serum, and irresponsive to anti?varicella?zoster virus?IgM (anti?VZV?IgM), anti?Japanese encephalitis virus?IgM (anti?JEV?IgM), anti?dengue virus?IgM (anti?DV?IgM), anti?hand, foot and mouth EV71 virus?IgM (anti?EV71?IgM) positive sera. No obvious reduction in serum anti?HV?IgM detecting capability was noticed after placement at 37 ℃ for 3 d. (2) In 144 sera samples in 120 patients with suspected hemorrhagic fever with renal syndrome, inconsistency was observed only in the anti?HV?IgM test results in 12 sera of 12 patients between the two kinds of kits, in which 8 primary sera samples were detected positive by the kit and negative by commercial ones (the secondary sera samples were positive for both kits); 3 primary samples (the secondary samples unavailable) were at the critical value for the kit and negative for commercial kits. Meanwhile, one other primary serum sample was positive for the kit and negative for the commercial ones (the secondary and tertiary ones positive for both). Conclusion The laboratory developed capture ELISA anti?HV?IgM diagnostic kits had favorable specificity, stability and sensitivity, suitable for the clinical diagnosis and epidemiological surveillance of HV infections.

Objective To evaluate the attractiveness of main components isolated and extracted from of Laminaria and applied them as the attractive baiting agents in molluscicides to enhance the killing effect of molluscicides. Methods A series of experiments using the attractant extracts of different main components of Laminaria were conducted at different temperatures and humidity conditions.  Results The initially identified attractants in Laminaria were dietary fiber and fucoidan. At 25 ℃, the 48 h Oncomelania hupensis?attracting rates of dietary fibers and fucoidan were 79.33% and 56.33%, respectively, higher than those at 15 ℃ and 35 ℃; under 60% relative humidity, the 48 h O. hupensis?attracting rates of fucoidan and dietary fibers were 47.67% and 72.33%, respectively, higher than those under 30% relative humidity. Conclusion The dietary fibers in Laminaria, which had a favorably attracting effect on O. hupensis, were a valuable material worth exploitation and utilization.

【Abstract】 Objective Explore the role of chigger mite in the transmission of hemorrhagic fever with renal syndrome (HFRS). Methods Chigger mites were collected from rats caught in the plague foci. HV was detected by Vero-E6 culture and IFA. HV-RNA from mites was tested by RT-PCR, and HV was located by hybridization histochemistry.  Results The infection rate of HV was 66.7% in chigger mites collected from rats which antigens were positive, however it was only 25.0% in mites from rats which antigens were negative. The result showed that chigger mite could transmit HFRS by stinging and vertical transmission. Conclusion It indicates that chigger mite is one of HFRS vectors, which roles in HFRS transmission can not be neglected. 

【Abstract】 Objective To clarify the natural infection situation of rodents by Hantavirus (HV) and HV strains in Zhejiang province in 2007，and provide science evidence for the prevention and control of hemorrhagic fever with renal syndrome (HFRS)．Methods Lung tissue and serum from rodent were sampled, and IgG antibody from serum was tested by indirect immunofluorscence assay and direct immunofluorscence assay was adopted to test HV antigens from lung tissues. HV was isolated by Vero?E6 cells, and HV strains were identified by Anti?McAb．Results A total of 1129 rodents were captured in 2007．The dominant specie was Apodemus agrarius, and the positive rate of HV antigen in rodent lungs was 3.0%. The IgG antibody of 57 blood samples was positive, and the positive rate was 8.0%.  Six  strains  of  hantaan (HTN)  virus  were  isolated,  five  strains  from A.agrarius  and  one  from  Rattus norvegicus.  Conclusion There  are  natural  foci  of  HFRS  which  main  infection  sources  are A.agrarius in Zhejiang province, and HTN strain could be the main prevalence strains of HV.

【Abstract】 Objective To test the bioactivity of essential oil extracted from Pogostemon cablin (Blanoa) Benth against Aedes albopictus Skuse, so as to find a new kind of mosquito repellent. Methods Essential oil was extracted from P.cablin by steam distillation. The bioassay against larvae and pupae of Ae. albopictus was carried out by immersion method. The adulticidal of P.cablin against Ae.albopictus was investigated by modified flask method. The repellent activity of pure P.cablin oil to Ae. albopictus was  assayed  by  topical  bioassay method  on  the  skin.  Results (1) P.cablin  oil  had  strong  toxicity  to  larvae  and  pupae  of Ae.albopictus. The LC50  values  of  P.cablin  oil  to Ⅰ, Ⅱ, Ⅲ, Ⅳ instar  larvae  and  pupae of  Ae.albopictus were 20, 34, 59, 60 and 187 μg/ml after treatment for 24 h, respectively. (2) The fumigation efficacy of P.cablin oil to adult Ae.albopictus was quick and efficient, and the KT50 values against Ae.albopictus were 14.692, 16.528 and 14.807 min at the dosages of 18, 36 and 54 μg/cm3, respectively. (3) The 100% protection time offered by P.cablin oil on the skin were (2.70±0.12) h, (4.40±0.10) h and (6.00±0.44) h at dosages of 1.5, 2.0 and 2.5 mg/cm2, respectively. Conclusion P.cablin oil has good bioactivity to Ae.albopictus, which is a kind of potential environment?friendly mosquito?repellent.

Objective To understand the natural infection rate of Angiostrongylus cantonensis in Achatina fulica and Ampullaria gigas from countryside of Maoming city of Guangdong province. Methods The Ac.fulica and Am.gigas collected from the district were digested with the Pepsin, and then larvae of An.cantonensis in the snails were identified and counted. Results 276 of Ac.fulica and 432 of Am.gigas were examined. The infective rate and average infectiosity of An.cantonensis in Ac.fulica were 38.41% and 36.65, and 20.14% and 8.33 in Am.gigas. Conclusion Maoming city is the natural focus of An.cantonensis in Guangdong, and the infection of Ac.fulica is more serious than Am.gigas now.

Objective To understand epidemiological characteristic of hemorrhagic fever with renal syndrome(HFRS) and provide information for control and prevention of HFRS in Yunnan province. Methods The data of cases of HFRS was collected in Yunnan province and human sera, the lung tissue and sera of rodents were collected in the surveillance counties. Then the antibody and antigen of Hantavirus was detected. Results The 46 cases had been reported in Yunnan province in 2005. The incident rate was 0.103/100 000. The main attacking areas were Dali prefecture, Kunming city and Honghe prefecture. The 8 species of 713 rodents had been captured and the 262 rodent sera and 407 human sera had been collected in Luxi, Xundian and Yongsheng counties where are surveillance areas. Rattus norvegicus and R.flavipectus were the dominant species in human living areas and Apodemus chevrieri was the dominant species in the fields. The Hantavirus carrying rate was 3.22%(23/713) in rodents and the rodents carrying virus were R.norvegicus, R.flavipectus, A.chevrieri, Eothenomys miletus and Suncus murinus. The positive rate of the antibody in human and rodent was 3.19%(13/407) and 4.96%(13/262) respectively. The latent infected rate was 3.00%(3/100) in Luxi county in the spring and summer. However the rate was 5.13%(4/78) in the autumn. So the rate was higher in the spring and summer than that in the fall. Conclusion There are the Rattus epidemic foci with the main hosts of R.norvegicus and R.flavipectus and there are also the Apodemus epidemic foci with the main hosts of A.agrarius and E.miletus in the surveillance areas. The increasing incident rate is related to the high rodents density and the rate of infected virus in the rodents.

Objective To investigate the types and their distribution of the hantavirus carried by Rattus norvegicus and R.flabipectus in Yunnan.Methods Rodents were captured in the main epidemic areas,and hantavirus antigens in rats lungs were detected by indirect immunofluorescence assay.Partial M and S segments were amplified in antigen-positive samples by RT-PCR,and then sequenced and analyzed.Results 307 rats were trapped in the main epidemic areas,and Hantavirus specific-antigens were identified in 14 out of the 307 R.norvegicus and R.flabipectus(4.56%).The genetic analysis of the partial S(600-999nt),G1(140-640nt) and G2(2003-2302nt) genes indicated that all hantaviruses in the 14 hantavirus-positive lung tissues are Seoul virus.The further genetic and phylogenetic analysis indicated that 14 viruses were grouped into 2 genetic subtypes,Seoul 1 and Seoul 3.Conclusion Yunnan was a Rattus-type HFRS epidemic areas.There are two subtypes of Seoul virus,ie.1 and 3 of Seoul virus,and they distribute widely in Yunnan.

Objective To understand epidemiological characteristic of hemorrhagic fever with renal syndrome(HFRS) and to offer a guidance of HFRS control and prevention in Yunnan province. Methods Collecting the data of cases of HFRS in Yunnan province and collecting human sera and the lung tissue and sera of rodents in the surveillance counties and detecting the antibody and antigen of hantavirus. Results The 55 cases and 2 deaths had been reported in Yunnan province in 2004. The incident rate was 0.13/100 000 and the case fatality rate was 3.64%. The main attacked areas were in Dali prefecture,Kunming city,Honghe prefecture,and Chuxiong prefecture. The 10 species of 803 rodents had been captured and the 314 rodent sera and 313 human sera had been collected in Luxi,Xundian and Yongsheng counties which were the surveillance areas. The rodents of Rattus norvegicus and Rattus flavipectus were the dominant species in human living areas and the rodents of Apodemus agrarius was the dominant species in these fields. The hantavirus carrying rate was 3.89% ( 26/668) in rodents and the virus carrying rodents were Rattus norvegicus, Rattus flavipectus, Mus musculus, Apodemus agrarius, Suncus murinus and Blarinella guadraticauda. The positive rate of the antibody in human and rodent was 3.50% and 2.24% respectively. The 16 species of 896 rodents had been captured in 10 counties (or city) of the western Yunnan province and the rodents of Eothenomys miletus was the dominant species. The hattanvirus carrying rate was 3.01% ( 27/896) in rodents and the rodents of virus carrying were R.norvegicus, R.flavipectus,M.musculus, R.nitidus, A.agrarius, S.murinus and B.guadraticauda. Conclusion There are the Rattus foci with the hosts of the main rodents of R.norvegicus and R.flavipectus and there are the Apodemus foci with the host of the main rodents of A.agrarius and E.miletus in the surveillance areas too. The incident had been increasing as the density of rodents and the rate of infected virus in the rodents was going up.

Objective To identify the condition of hantavirus infection and genetype as well as to determine the risk factors of hantavirus infection in rodents captured in a military unit in order to provide scientific basis for prevention and control. Methods The captured rodents were classfied and the density of rodents was calculated. RT-PCR technique was used to amplify the partial M fragments. Results The infection rate of hantavirus in the 14 captured rodents was 21.43%. One sample ( from Rattus norvegicus) was positive by RT-PCR amplified. Nucleotide sequences analysis showed that the virus detected all belonged to SEO-type. The crowd positive rate of IgG was 3.64%. Conclusion The SEO-HV infection of rodents exists in the military unit. It is necessary to reinforce epidemic surveillance to prevent spread of the disease.

Objective To investigate the vertical distribution characteristics and Fauna of flea in the Wuliang Mountain Nature Reserve in Jingdong.Methods Trap for small mammals in November December,1998.Results A total of 507 individuals belonging to 26 species,15 genera and 5 families was collected.19 species(73.1%) are oriental forms,5 species( 19.2%) are palaearctic forms,and 2 species(7.7%) are wide spread forms.On the other hand,the flea fauna of Wuliang Mountain shows a high degree of endemicity(15 endemic species of Hengduan Mountains area,accounting for 58% of total species discovered).The species diversity,evenness and ecological dominance indices of flea communities in 4 main ecological environments were measured and compared.Conclusion According to the results of investigation,the diversity of flea communities is the highest in the Warm taiga and Wet evergreen broadleaf forest and lowest in subalpine shrubberg and Grasslands.The species diversity index decreased gradually with the ascending altitude.In addition,the characteristics of flea and hosts fauna and the boundary line between Palaearctic and Oriental Realms in Hengduan Mountains of Northwestern and Southwestern Yunnan were also analyzed and discussed.

Objective To explore a quick method to gain a large number of unfed filial larvae of Leptotrombidium scutellare so as to suit the needs of studying the transovarian transmission of pathogen in chigger mites.Methods Small blackboards were placed on the grassland in the endemic areas of HFRS or tsutsugamushi disease each for 10 minutes.The larvae on the blackboards were counted and their species were identified.This method could collect a large mumber of unfed filial larvae of L.scutellare.About 20-30 larvae of L.scutellare were used as a pool to bite a suckling mouse to isolate Hantavirus(HV),to bite a mouse to isolate Orientia tsutsugamushi(Ot).Results Of 24 suckling mice bitten by the larvae,5 strains of HV were isolated.Among 6 mice bitten by the larvae,2 were confirmed by detection of Ot.The larvae used in this study had never bitten,while the mice bitten by these larvae could be infected by HV and Ot,indicating that the pathogen carried by these larvae could only be originated from it parent mite via transovarian route.Conclusion Small blackboard can collect a large number of unfed filial larvae of L.scutellare on the grassland in the endemic areas.It offers a rapid,simple and economic method in studying the transovarian of pathogen in mites.The results demonstrate that:HV and Ot can be transferred via transovarian transmission in mite;and therefore, L.scutellare can serve as a transmitting vector of HFRS and tsutsugamushi disease.

Objective:To study the mosquito natural infection with Japanese encephalitis(JE) virus and evaluation on their vector status.Methods:Collecting mosquitoes from the indoor and the stables of livestocks in villages in the night,and the outdoor bamboo forests in the daytime.Using C6/36 or BHK ₂₁ cells and suckling mice to isolate viruses.Results:92 748 adult female mosquitoes belonging to 45 species of 6 genera were captured.Forty-two strains of JE virus were isolated from 13 species of mosquito,of those,15 strains were isolated from Culex tritaeniorhynchus,5 strains from Cx.whitmorei,4 strains from Cx.pseudovishnui,2 strains from Cx.fuscocephalus,4 strains from Anopheles sinensis,3 strains from Aedes vexans,2 strains from Ae.albopictus,2 strains from Ae.lineatopennis,a strain from Cx.gelidus,a strain from Cx.annulus,a strain from An.vagus,a strain from Ae.assamensis,a strain from Mansonia uniformis.Conclusions: Cx.tritaeniorhynchus might be the principal transmitting vector of JE in Border area,Yunnan.Cx.whitmorei,Cx.pseudovishoui,Ae.vexans and Ae.albopictus are also considered to be transmitting vector of JE in Yunnan.So Culex are regarded as the main vector of JE in night-actived mosquitoes and Aedes are regarded as the main vector of JE in daytime-actived mosquitoes in the area.

Objective:To study on the mosquito communities and the geographical niche of border area inYunnan province.Methods:Alluring by man body in day time and traping by trapper at night.Results:The mosquito communities were investigated in 15 border counties in Yunnan.The results showed that there were 6 dominant species of night-actived mosquitoes around domestic animal and human house in the rural area and 5 dominant species of day-actived mosquitoes in the groves of bamboo and woods.They were: Culex tritaeniorhynchus,Culex pseudovishnui,Culex fuscocephala,Culex whitmorei,Anopheles sinensis,Anopheles vagus,Aedes albopictus,Aedes pseudabopictus,Aedes annandale,Aedes vexans and Armigeres subalbatus.The diversity indexof night-actived mosquito communities were:Cangyuan(2.092 0),Ruili(2.035 5),Yingjiang(1.9521),Jinghong(1.8193),Maguan(1.7234),Genma(1.6857),Mengla(1.6717),Jingping(1.6709),Shuangjiang(1.6488),Menglian(1.6444),Menghai(1.568 8),Wangding(1.4616),Hekou(1.427 1),Luxi(1.2940) and Baoshang(1.2364).The diversity indexof day-actived mosquito communities were:Hekou(2.1630),Jinghong(1.9355),Mengla(1.7447),Cangyuan(1.6756),Genma(1.6734),Yingjiang(1.625 8),Luxi(1.601 5),Wangding(1.594 8),Ruili(1.531 8),Menglian(1.161 9) and Menghai(1.056 1).Conclusion:Thebiggest geographical niche breadth to night-actived mosquitoes wasCulex pipiengsquinquefasciatus(0.858 6),Culex tritaeniorhchus(0.838 2),Culex pseudovishnui (0.8015) and the biggest geographical niche breadth to day-actived mosquitoes wasAedes albopictus(0.895 5).

Objective: It was to further observe dynamic changes on proliferation of hemorrhagic fever with renal syndrome virus (HFRSV) in gasmid mite. Methods: The titres of HFRSV in gasmid mite were dynamic observed from cultured cells. Results: The titres of HFRSV were detected in different generation of gasmid mite which separated from HFRSV antigen positive or negative mice, the titres were in 10 ^-1～10 ^-6,but the titre of generation was as more as 10 ^-3～10 ^-5 than the last generation. It was found by anti-Mp/Np McAb that the higher the titre of virus was, the higher the toxicity was. Conclusion: The results demonstrate that the HFRSV could proliferate in gasmid mite and be transmitted by trans-stadial.

In order to clarify the routes of transmission of hemorrhagic fever with renal syndrome (HFRS), we carried out a series of studies on the relationship between chigger mites and HFRS. The results show that gamasid mites and chigger mites were the dominant species in litters of Apodemus agrarius-the main reservoir of HFRS,their seasonal distribution were correlated with the incidence of human HFRS, they could pierce the mormal skin of rodent and human to suck blood, those two mites could naturally be infected by HFRS virus. HFRS virus could be transmitted through the bite of mites among rodents and through transovarial transmission in mites. The antigenicity of HFRS virus isolated from mice and mites were identical. The results indicated that chigger mites can serve as transmitting vector of field rodent type of HFRS and act as a reservoir host as well.