Objective To evaluate the level of resistance of Aedes albopictus to pyrethroid insecticides in Guiyang,China,and identify mutations in the knockdown resistance gene, so as to provide a scientific basis for the control of Ae. albopictus in the region.Methods From July to August 2022,the larvae of Ae. albopictus were captured at different locations of Guiyang and then reared to F1-F2 generations in the laboratory. The resistance to pyrethroid insecticides was determined by using the dipping method for larvae and the World Health Organization tube method for adult mosquitoes. The genomic DNA of individual adult Ae. albopictus mosquito was extracted for PCR amplification and sequencing to detect knockdown resistance gene mutations. The Chi-square test was used to analyze the frequency differences of mutant genes between groups.Results The median lethal concentrations of deltamethrin, permethrin, and beta-cypermethrin against Ae. albopictus larvae in Guiyang were 0.559, 0.021, and 0.012 mg/L, respectively;and the resistance ratios were 433.33, 46.67, and 16.44, respectively. The mortality rates of adult Ae. albopictus mosquitoes exposed to 0.03% deltamethrin, 0.4% permethrin, and 0.08% beta-cypermethrin were all <80%. No mutations were detected at the 1016, 1532, and 1534 loci in the sensitive population of Ae. albopictus. Knockdown resistance gene mutations were found at all the three loci in the natural population of Ae. albopictus. There were two alleles at 1016 locus, which were wild-type GTA (V) (76.35%) and mutant GGA (G) (23.65%), with no statistically significant differences in frequency of mutant genes between the sensitive and resistant phenotypes (χ²=1.810, P=0.178); There were three genotypes at 1016 locus: wild-type homozygous V/V (58.78%), wild/mutant heterozygous V/G (35.14%),and mutant homozygous G/G (6.08%). There were two alleles at 1532 locus, which were wild-type ATC (I) (99.83%) and mutant ACC (T) (0.17%),with two genotypes of wild-type homozygous I/I (99.66%) and wild/mutant heterozygous I/T (0.34%). There were two alleles at 1534 locus, namely wild-type TTC (F) (48.48%) and mutant TCC (S) (51.52%),with no statistically significant difference in frequency of mutant genes between the sensitive and resistant phenotypes (χ²=0.603, P=0.437); There were three genotypes at 1534 locus: wild-type homozygous F/F (8.11%), wild/mutant heterozygous F/S (80.74%),and mutant heterozygous S/S (11.15%).Conclusions Larval and adult Ae. albopictus mosquitoes in Guiyang have developed medium-to-high resistance to the three pyrethroid insecticides and mutations in the knockdown resistance gene,but with no significant association between the mutations and the resistant phenotypes. The level of resistance in the region should be continuously monitored to guide the scientific and rational use of insecticides to effectively control mosquitoes and delay the evolution of insecticide resistance.

Objective To investigate the species composition of edible rodents and rodent-borne pathogens in some ethnic minority areas in Guizhou province, and to provide basic data for the prevention and control of rodents and rodent-borne diseases. Methods Edible rodents were preliminarily investigated through interviews with local ethnic minority people. Rodents were captured by the night trapping method in the mountainous forest areas of three counties and four towns in Qiandongnan Miao and Dong autonomous prefecture. Rodents were identified and dissected and the viscera were stored at -20 ℃ and transported to the laboratory. PCR was used to detect rodent-borne Leptospira, Hantavirus, and Yersinia pestis. Bacteria were isolated and identified from two intestinal samples. Results A total of 141 (20.74%) rodents were captured, which belonged to 2 families, 5 genera, and 10 species, and the most frequently consumed rodents were Berylmys bowersi and Niviventer coninga. Leptospira (positive rate, 13/48, 27.08%), Hantavirus type I (positive rate, 1/141, 0.71%), and Hantavirus type Ⅱ (positive rate, 18/141, 12.77%) were detected, while Y. pestis was absent (0/125). Four non-diarrheagenic bacterial species were isolated from the duodenum of B. bowersi, while two of the four bacterial strains isolated from N. coninga were diarrheagenic. Conclusion The dominant species of edible rodents in mountain forests are B. bowersi and N. coninga. These species are major hosts of Leptospira and Hantavirus and present a high risk of disease transmission. We suggest to strengthen the surveillance of rodents and rodent-borne diseases in this area, and pay attention to the publicity and education of rodent-borne diseases to reduce the risk of infection.

Objective To investigate the mosquito species and the distribution of mosquito-borne viruses in some regions of Guizhou province, China, and to provide a basis for the prevention and control of mosquito-borne diseases in this area. Methods Mosquitoes collected with trapping lamps were identified, mosquito-borne viruses were identified by molecular biological methods, and a phylogenetic tree of virus strains was constructed using bioinformatics software. Results A total of 27 169 mosquitoes (9 species, 3 genera) were collected in Zhongchao town of Liping county and Yangchang town of Wudang district (Guiyang city) of Guizhou province in June 2019. The dominant species was Anopheles sinensis (13 712/27 169,50.47%), followed by Culex tritaeniorhynchus (12 444/27 169,45.80%) and other species (70/27 169,0.26%). A virus strain isolated from a mosquito sample (LK6110) from Zhongchao town was identified as Japanese encephalitis virus genotype Ⅲ (JEV Ⅲ). Conclusion In this investigation, Yangchang town was dominated by An. sinensis and Zhongchao town was dominated by Cx. tritaeniorhynchus, and JEV Ⅲ was isolated from Cx. tritaeniorhynchus in Zhongchao town.

Objective To investigate the current status of resistance to commonly used insecticides in Aedes albopictus in Xingyi and Chishui cities of Guizhou province, China, to explore the killing effect of Bacillus thuringiensis subsp. israelensis on Ae. albopictus larvae in Chishui, and to provide a scientific basis for the prevention and control of Aedes vector and related infectious diseases. Methods In September 2018 and July 2019, Ae. albopictus larvae were collected from small water containers in communities in different locations of Xingyi and Chishui and were reared to obtain the F1 to F2 generations in the laboratory. The larval dipping method and the contact tube method recommended by WHO were used to investigate the insecticide resistance of Ae. albopictus larvae and adults, respectively, and determine the degree of insecticide resistance. Results The resistance ratios of Ae. albopictus larvae against deltamethrin, beta-cypermethrin, permethrin, and DDVP were 44.78, 39.18, 113.74, and 2.74 folds, respectively, in Xingyi city, and 38.38, 24.25, 26.37, and 1.64 folds, respectively, in Chishui city. In addition, the resistance ratios of Ae. albopictus larvae against propoxur and B. thuringiensis subsp. israelensis were 7.51 and 1.28 folds, respectively, in Chishui. The 24-hour mortality rates of adult Ae. albopictus mosquitoes in Xingyi against deltamethrin, beta-cypermethrin, permethrin, and fenitrothion were 27.22%, 57.89%, 46.75%, and 100%, respectively. The 24-hour mortality rates of adult mosquitoes in Chishui against deltamethrin, beta-cypermethrin, and permethrin were 53.00%, 93.33%, and 94.40%, respectively, and the mortality rate against propoxur was 99.20%. Conclusion Ae. albopictus larvae in both cities have developed moderate or above resistance to pyrethroid insecticides and are sensitive to DDVP. Ae. albopictus larvae from Chishui have low resistance to propoxur and are sensitive to B. thuringiensis subsp. israelensis. In both Xingyi and Chishui cities, Ae. albopictus adults have resistance or suspected resistance to pyrethroid insecticides and are sensitive to fenitrothion or propoxur. It is recommended to adhere to the principle of integrated vector management in both cities, timely monitor the level and changing trend of insecticide resistance of Ae. albopictus, suspend the use of high-resistance insecticides, and adopt an appropriate rotation or combination strategy, so as to delay the development of insecticide resistance.

Objective To establish a RT-hemi-nested PCR assay for laboratory detection of mosquito-borne alphaviruses based on the universal primers of mosquito-borne alphaviruses. Methods Three universal primers of mosquito-borne alphaviruses were designed in the conserved regions based on the whole genome sequence of alphaviruses in GenBank. The RT-hemi-nested PCR assay was established using the cDNAs of Sindbis virus (SINV) and Chikungunya virus (CHIKV) as templates under optimized conditions; the sensitivity and specificity of this method were validated and mosquitoes collected in the field were tested. Results The sensitivity test results showed that the lowest detection limit of SINV and CHIKV was 3×10³ and 3×10⁴ copies/µl. The sensitivity test results showed that the RT-hemi-nested PCR was only able to amplify the alphavirus. The established method was used to detect mosquito specimens collected in the field. The results showed that mosquito-borne alphavirus was not detected in all samples. Conclusion The RT-hemi-nested PCR assay established in the study is highly specific and sensitive and can be used for epidemiological survey on alphavirus infection.

Objective To investigate the distribution of mosquito species and mosquito-borne viruses in different regions of Guizhou province, China, and to provide evidence for the prevention and control of mosquito-borne diseases. Methods Mosquito samples were collected using mosquito lamps in Liping, Congjiang county, Huaxi, and Wudang district in Guizhou province in August 2018. Virus species were identified by molecular biology methods and the sequences of newly isolated viruses were analyzed using bioinformatics software. Results A total of 17 018 mosquitoes belonging to 3 genera and 4 species were collected from the above four sites in Guizhou province, including Culex tritaeniorhynchus (34.0%), Cx. pipiens pallens (2.3%), Anopheles sinensis (24.7%), and Armigeres subalbatus (39.0%). Among these species, Ar. subalbatus was the most collected one. Two strains of viruses were isolated from mosquito specimens and identified by molecular biology. The virus strain GZWK isolated from Cx. tritaeniorhynchus belonged to genotype I Japanese encephalitis virus (JEV), and the virus strain GZWA isolated from Ar. subalbatus belonged to genotype Ⅲ JEV. Conclusion Armigeres subalbatus was the dominant species in the regions investigated in Guizhou, and the Japanese encephalitis virus was also isolated in the study. The GZWK strain has a close phylogenetic relationship with the genotype I JEV VN105 strain from Vietnam, and the GZWA strain has a close phylogenetic relationship with the genotype Ⅲ JEV FJ0339 strain from Fujian province, China.

Objective To investigate the distribution patterns of mosquitoes and mosquito-borne viruses in northeast Guizhou province. Methods In 2017, host-seeking mosquitoes were collected from livestock sheds using Ultraviolet lights in Dejiang and Jiangkou, Guizhou province. The mosquito specimens were classified according to morphology and stored in liquid nitrogen. All the samples were incubated with BHK-21 and C6/36 cells for virus isolation and detected the virus genes. The virus isolates were identified and analyzed by molecular biological methods. Results In total, there were 7 380 mosquitoes from 3 genera and 3 species collected from Dejiang and Jiangkou, Guizhou province, 61.55% (4 542/7 380) of which were Armigeres subalbatus and 26.80% (1 978/7 380) were Anopheles sinensis. Out of the 3 virus strains isolated from the mosquitoes, One (GZDJ1765) was identified as typeⅠof Japanese encephalitis virus (JEV) isolated from Culex tritaeniorhynchus and two (GZDJ1746-1, GZDJ1752-1) were identified as Getah virus isolated from A. subalbatus. Three mosquito pools (GZDJ1704, GZDJ1743-2, GZDJ1751-2) tested positive for JEV genes y by PCR. Conclusion Armigeres subalbatus was the predominant species in northeast Guizhou. JEV and GETV were isolated.

Objective To investigate epidemiological characteristics of imported dengue fever in Daozhen county, the species and density of local Aedes mosquitoes, and provide basis for prevention and control. Methods Epidemiological investigation was carried out on dengue fever cases and other returnees in July 2016. The dengue IgM antibody of the serum returnees were detected by ELISA, and investigating the Aedes mosquitoes in the town where the cases reside was carried out by human baiting and Breteau index(BI). Results There were 5 clinical cases, 2 suspected cases, 1 asymptomatic infection among all 26 returnees from Maldives, with morbidity rate 30.77%. Six sera were positive for dengue IgM antibody, 7 cases were treated and recovered. Other 19 asymptomatic individuals were quarantined for 14 d, and no new clinical cases emerged. Investigating the Aedes mosquitoes in towns of Yuxi, Hekou, and Zongping revealed that landing rate on human was 2.4, the mosquito density was more than C level (human landing rate less than 1.5). BI was 7.0, slightly higher than the threshold for the spread of dengue fever (BI ≤ 5). Conclusion An imported dengue fever outbreak from Maldives occurred in Daozhen county in 2016. There was no secondary dengue transmission locally, because of the effective preventive measures.

This paper reports 2 genera, 16 species of hematophagous midges in 2016 in Dejiang county, Guizhou province, China, among which 13 species in Culicoides and 3 species in Lasiohelea. A new species C. (Oecacta) qinglongensis Liu, sp. nov. was described. Five species, C. actoni, C. kongmiaoensis, C. newsteadi, C. parahumeralis, and La. danxinensis were recorded for the first time in Guizhou province. Culicoides (O.) qinglongensis Liu, sp. nov. wassomewhat allied to C.(O.) okinawensis Arnaud, 1956, but was distinctly different from wing length 1.38 mm, antennasensilla coeloconica present on segments 3-14, antennal ratio (AR)1.28, mandible with 17 teeth of female; and shape of aedeagus, parameres, and basistyle with ventral root of male of C. (O.) okinawensis Arnaud, 1956. The type specimens are deposited in the PLA Shenyang Command Center for Disease Control and Prevention (Shenyang 110034).

Objective In order to provide scientific basis for Brucellosis control and prevention, sero-epidemiological survey, Brucella isolation and genetic characteristic analysis were conducted for the high-risk population in a human Brucellosis epidemic in Weining county of Guizhou province. Methods Tube agglutination test was used to detect the anti-Brucella antibody for the high-risk human population. Rose Bengal Plate Test was applied to detect the antibody in goat blood samples. The blood of antibody positive human population was collected for Brucella isolation. Conventional methods, genus specific BCSP31-PCR and species-specific AMOS-PCR were used to identify the bacteria strain, and the genetic characteristic was analyzed using MLVA and MLST techniques. Results Six people of 43 high-risk populations were confirmed as anti-Brucella antibody positive, 64 out of 302 goat blood samples were anti-Brucella antibody positive, with positive rate of 21.19%. A suspected Brucella strain were isolated from one of the high-risk human populations and was identified as B. melitensis biovar 3. MLVA-16 analysis indicated that the bacteria strain was most closely clustered with B. melitensis biovar 3. Multilocus sequence typing analysis indicated the strain was ST8. Conclusion Genetic characteristic of Brucella strain isolated from the Brucelosis epidemic was consistent with that of M. melitensis biovar 3. Although antibody and Brucella were detected, the high-risk populations did not displayed symptoms, so all of them were asymptomatic infections. The epidemic was seemingly imported due to goats trading, suggested that health and animal disease control and prevention departments and doctors should pay great attention to it.

Objective　Borrelia burgdorferi were isolated from captured ticks in the border areas between Guangxi and Guizhou, in order to identify the vector of Lyme disease in Guangxi Zhuang Autonomous Region and Guizhou province. Methods　The BSK?Ⅱ culture media were used to isolate B. burgdorferi from ticks. The 5S-23S rRNA gene spacer region of the isolates was amplified by the PCR, and the product was cloned and sequenced. The sequencing results were compared with the 5S-23S rRNA gene spacer region of the B. burgdorferi strains from the gene bank and analyzed for the homology to identify their genotypes. Results　One B. burgdorferi was isolated from the captured Ixodes sinensis (named QLT1). The isolate was identified as the genotype B. valaisiana. Conclusion　I. sinensis is the likely vector of Lyme disease in Guangxi Zhuang Autonomous Region and Guizhou province.

　　【Abstract】　Objective　To investigate the influence factors in areas where rabies raged in Guizhou province, and provide the evidence for the establishment of focused intervention measure suitable for the rural areas. Methods　A multistage sampling method was used in this study and all the data were analyzed by Excel 2003 after logging data with Epi Data. Results　In recent years, the incidence of rabies in Zhenning county was very serious. The incidence rates of rabies in 2005 and 2006 were 6.16/10 thousand and 5.19/10 thousand respectively, which mainly caused by bite of dogs. Because of the large number of the dogs, the injury rate of the crowd was also higher. It was 6.47% in 2006, and there was significant difference between exposure rate of students （10.58%） and that of farmers （5.05%）（χ2＝36.57, P＜0.001）. About 31.40% exposed crowd were not done the medical treatment, and 35.41% exposed crowd without inoculation rabies vaccines, only 4.26% of Ⅲ° exposed crowd with rabies immunoglobulin. Villagers knew less about the knowledge of rabies prevention and control. Conclusion　The main factors leading to the rage of rabies were large number of dogs, low immunization rate of the crowd, high exposure rate of the public and low treatment rate of exposed crowd in the investigated districts.

Objective According to cases surveillance data of Japanese encephalitis(JE) from 2004 to 2005 in Guizhou province, understand the proportion of JE diagnosed cases to reported JE cases and master the epidemic status of JE to provide the science base for the control of JE case. Methods To analyze synthetically JE epidemic status based on epidemic situation surveillance management system, JE cases questionnaire, laboratory results and JE cases information of 2 surveillance counties. Results There were 1230 and 1038 cases in 2004 and 2005 respectively. The cases under 15 years old accounted for 96.58%(1188/1230) and 97.69% (1014/1038) respectively. The ratio of male to female was 1.58∶1 and 1.57∶1, respectively. The cases peak was in the 7-8 month, accounted for 78.21%(962/1230) and 79.09%(821/1038). The cases accounted for 88.36%(319/361) in two national surveillance counties. It was remarkable seasonal and highly dispersed for JE. The population with vaccine history was only 6.90%(26/377) and 8.86%(32/361). The positive rate of JE IgM antibody was 74.90%(188/251) and 71.74%(259/361) respectively. And it reached 71.88%(23/32) in surveillance counties. The JE cases reduced 15.61% in 2005 compared to that of 2004, and it decreased 39.47% in surveillance counties. Conclusion The diagnosed JE cases accounted for 71.88%-74.90% in Guizhou province. It should further strengthen JE surveillance system, enhance laboratory diagnosis technique so as to diagnize effectivly JE cases, and put the emphasis on the immunization of JE vaccine to the population of under 15 years old.

Objective To analyse prevalence trend of Japanese encephalitis(JE) in 1997-2004 in Guizhou province and to supply scientific gist for the prevention and Control strategy. Methods Analysis information was got from the epidemic surveillance and JE Cases Questionnaire. Results There were accumulative total 13 664 JE cases and 540 death cases. The annual average Morbidity and Mortality and fatality rate were 4.65/100 000 and 0.18/100 000 and 3.95%,respectively. Male to female was 1.48∶1. Children of decentralization resident population accounted for 67.54%( 9 228/ 13 664) and students were 23.06%( 3 151/ 13 664). Younger than 10 years old children case accounted for 88.00%( 12 024/ 13 664);Season distribution was from June to October and high peak period was from July to August. Conclusion The results showed that JE cases were mainly younger than 10 years old children in Guizhou province. The cases season were from June to October and high peak period lasted two months from July to August. The high risk prefectures were Zunyi and Bijie. There were so many cases with out vaccine history and unknown history during 1997-2004. The preventive strategies are to be that the health education and propaganda should be conducted. All-around control countermeasure such as preventive and destroying mosquitoes and JE vaccine immunization should be carried on to decrease the morbidity and mortality of JE in Guizhou province.

Objective Analyses epidemiological status of rabies and searches for the control countermeasure according to the rabies cases surveillance in Guizhou province in 2004.Methods Analyse synthetically information of epidemic situation surveillance administration system and rabies cases questionnaire form.Results Totally 206 rabies cases were reported in Guizhou province in 2004 and the morbidity was(0.53/100 000).Mortality was the same as morbidity.Among them,the rabies cases of Anlong county is account for the 65.67%((44/67)) of Qianxinan prefecture.Though there were rabies cases in the whole year,the peak was March and from July to October and the rabies cases from July to October amount for 46.12%((95/206).Proportion of male and female was 2.68∶1.The most cases were farmers and students which amount to 57.28% and 27.18% respectively.The high risk age was(10-44) years and amount to 66.5%.The youngest rabies case was 2 years old and the oldest was 76 years old.Conclusion Rabies cases mostly were farmers and students in Guizhou.The high peak season of rabies cases is summer and autumn.High risk prefecture is Qianxinan,Qiannan,Qiandongnan and Anshun city.Suggestion more works should be done according to "Administrating,Immunizing and Destroying" principle.Strengthen propaganda and health education,and let people realize the importance of injecting the rabies vaccine and immunize on one's own initiative.It will decline the rabies morbidity and mortality in Guizhou province and protect the health of people.