| BackgroundBartonella spp.are a group of bloodthirsty,oxidase negative,gram negative,facultative cell-parasitic and aerobic bacteria,which are shaped like a tiny,polymorphic,slightly curved rod body.They mainly parasitize host animal and human vascular endothelial cells,epithelial cells and red blood cells,which can cause such as cat scratch disease in humans,endocarditis,trench fever,Carrion disease and Bartonella disease.Since the pathogen was first isolated in 1919,new species and subspecies of Bartonella have been derived,attracting much attention due to its wide variety,wide pathogenicity and outbreaks.Rodents are diverse,widely distributed and closely related to human beings.They can carry a variety of pathogenic organisms,and are the natural host and main source of infection of natural epidemic diseases such as leptospirosis and hemorrhagic fever with renal syndrome.They are often used for monitoring and warning the biological characteristics and epidemic characteristics of related natural focal diseases.At present,the most species of Bartonella have been isolated from,and 22 species of Bartonella have been detected from more than 40 species of rodents.Rodents are generally considered to be the natural host and the most important reservoir of Bartonella.Since Bartonella was first isolated from rodents in Yunnan province,studies on rodent infection with Bartonella have been carried out in various regions of China,mainly involving the infection status of rodents,molecular evolution and phylogeny.Liupan Mountain,located in the southernmost part of Ningxia Hui Autonomous Region,is listed as a national nature reserve and national forest park.It has a complex and diverse terrain and rich natural landscape.Rodents and blood-sucking arthropods are widely distributed and diverse,which have close contact with human beings.Since it was set up as China’s first tourism poverty alleviation and development pilot zone,the tourism industry in Liupan Mountain area has been greatly developed,and the risk of Bartonella infection in the population in Liupan Mountain area is also increasing.However,studies of Bartonella infection in rodents and population in this area do not exist.Therefore,it is necessary to investigate Bartonella infection in rodents and healthy population in Liupan Mountain area.Objectives(1)To understand the density,distribution characteristics and parasite carrying situation of rodents in Liupan Mountain area of Ningxia.(2)To analyze Bartonella infection and mixed infection in rodents in Liupan Mountain area of Ningxia.(3)To investigate the serum prevalence of Bartonella in healthy people in Liupan Mountain area of Ningxia,and explore whether there is bartonella infection in local healthy people.MethodsResearch was carried out in three survey sites in Liupan Mountain area of Ningxia in September 2020.In the process of specimen collection,rodents were first captured by night trapping method.Species identification was carried out by morphological method.Organ samples were obtained by aseptic anatomy,and the species,gender,collection location and habitat information of rodents were recorded.At the same time,ticks,mites and fleas parasitized on the body surface of rodents were collected,and corresponding information was recorded.Biological slides were made for those with typical morphology.At the time of the investigation,100 samples of 2-3ml fresh serum from healthy people were collected in the physical examination department of Jingyuan County Hospital.In laboratory tests,DNA was extracted and Bartonella and other pathogens positive samples were screened by RT-qPCR.GltA gene and rpoB gene were amplified and sequenced for phylogenetic analysis to obtain Bartonella genotype.ELISA was used to detect Bartonella antibody in serum of healthy people.The χ2 test or Fisher’s exact probability method was used to analyze whether there was significant difference in the infection rate of Bartonella among different genders,rodent species,survey sites and habitats.Results(1)Basic information of rodents:A total of 88 rodents were captured,and the rodent density was 11.00%.The rodent density was the highest in Old Longtan scenic spot(21.00%),and the lowest in Huanghua township(6.75%).There were 10 females and 71 males,7 of which could not be identified.The ratio of male to female was 1:7.10.The composition ratio of Apodemus peninsulae(38.03%)was the largest among males,and that of Cricetulus migratorius(40.00%)was the largest among females.A total of 88 rodents were identified as belonging to 7 species,5 genera,3 families.Apodemus peninsulae was the largest rodent species(36.36%,32/88),followed by Cricetulus migratorius(26.14%,23/88)and Tscherskia tritonde Winton(21.59%,19/88).In addition,10 Apodemus agrarius(11.36%,10/88),2 Niviventer confucianus(2.27%,2/88),and 1 Eozapus setchuanus Pousargues and Mus musculus(1.14%,1/88)were captured.There were 91 ticks among the rodents.The overall tick infection rate was 42.05%(37/88),and the tick index was 1.03.There were 57 mites,and the overall mite infesting rate was 28.41%and the mite index was 0.65.There were 44 fleas.The overall flea infection rate of rodents was 19.32%,and the flea index was 0.50.(2)PCR test results of pathogens:41 Bartonella positive specimens,5 Borrelia burgdorferi positive specimens,8 Ehrlichia positive specimens,and the detection results of SFTS V,Rickettsii mooseri and Hantavirus were all negative.(3)Analysis of rodent infection with pathogens:The infection rate of Bartonella in rodents was 46.59%(41/88),and there was significant difference among different survey sites(P<0.05).The highest infection rate of Bartonella was 83.33%(35/42)in Longtan scenic spot.However,there was no significant difference in the infection rate of Bartonella among different rodent species,genders and habitats(P>0.05).The infection rate of Borrelia burgdorferi in rodents was 5.68%(5/88).However,there was no significant difference in the infection rate of Borrelia burgdorferi among different rodent species,male and female,and habitats(P>0.05).Ehrlichia infection rate in rodents was 9.09%(8/88).However,there was no significant difference in the infection rate of Ehrlichia among different rodent species,male and female,and habitats(P>0.05).The coinfection rate of three pathogens in rodents was 10.23%(9/88).The double infection rate of Bartonella and Ehrlichia was 5.68%(5/88),the double infection rate of Bartonella and Borrelia burgdorferi was 2.27%(2/88),and the double infection rate of Borrelia burgdorferi and Ehrlichia was 1.14%(1/88).The triple infection rate of Bartonella,Borrelia burgdorferi and Ehrlichia 1.14%(1/88).(4)Genetic evolution analysis of Bartonella:Genetic evolution analysis based on gltA gene showed that 11 samples,represented by JY-37,clustered with B.grhamii as a large branch,with homology ranging from 95.52%to 99.63%.The four samples represented by JY-4 and B.phoceensis from Rattus norvegicus,France,were aggregated into one branch,and their homology ranged from 96.33%to 97.67%.The results of genetic evolution analysis based on rpoB gene showed that 13 samples represented by JY-14 were clustered with B.grahamii as a large branch,and their homology ranged from 97.03%to 100%.Five specimens,including JY7,and B.phoceensis from Rattus norvegicus,France,were aggregated into one branch,with homology ranging from 96.66%to 97.16%.The results based on the two gene fragments were totally the same:rodents were infected with B.grahamii and B.phoceensis in Liupan Mountain area of Ningxia.Only JY-9 and JY-32 had different results,suggesting that the same rodent might be infected with B.gramii and B.phoceensis simultaneously.(5)Serum ELISA test results of healthy people:A total of 8 samples were positive by ELISA,and the positive rate of Bartonella antibody in healthy people in Liupan Mountain area of Ningxia was 8.00%,indicating the presence of previous infections with Bartonella in healthy populations in the region.Conclusions(1)There is a high density and abundant species of rodents in Liupan Mountain area of Ningxia.At the same time,it is common for rodents to carry blood-sucking arthropods.(2)In Liupan Mountain area,Bartonella infection in rodents is highly popular.In three survey points,rodent infection rate in Old Longtan scenic spot is highest.Two species of Bartonella,B.grahamii and B.phoceensis,were found in rodents in Liupan Mountain area of Ningxia,among which B.phoceensis was first found in rodents in Ningxia,existing in Apodemus peninsulae and Apodemus agrarius.(3)Coinfection of Bartonella,Borrelia burgdorferi and Eichliella were found in rodents in Liupan Mountain area.Ehrlichia was detected in Apodemus peninsulae,Cricetulus migratorius and Cricetulus triton in Ningxia Hui Autonomous Region and Borrelia burgdorferi was detected in Cricetulus migratorius and Cricetulus triton in Liupan Mountain area for the first time in this study.(4)There were previous infections of Bartonella in healthy people in Liupan Mountain area of Ningxia. |
PDF Full Text Request