Background Survey Of Pathogens And Ectozoic Parasites Carried By Rats In The Port Of Jilin Province Adjacent To DPRK In 2021

Objective:Jilin Province is located in northeastern China,adjacent to North Korea,with a1334-km border between China and DPRK,including 1289 km of land border.Yanji,Hunchun,Baishan,and Tonghua are the four representative port area adjacent to DPRK of Jilin Province,which are similar to DPRK in terms of ecological environment,vector hosts,and pathogenic basis;moreover,these four port areas adjacent to DPRK are all land crossings,where rats are highly mobile and can freely migrate across the border,and the risk of rodent-borne disease introduction and transmission is high.However,there are few reports on vector organism surveillance in DPRK,and a full understanding of the epidemiological situation and spread trend of rodent-borne diseases in the adjacent areas of China and DPRK can effectively promote the prevention and control of rodent-borne diseases in the border areas of the two countries.To provide the theoretical basis for evaluating the risk of transmission of rodent-borne diseases and to provide comprehensive prevention and control measures,an investigation of important vectors(rats)and their pathogens was carried out in Yanji,Hunchun,Baishan,and Tonghua in 2021.Methods:An on-site survey of rats and rat parasitic vectors in the port area adjacent to DPRK in Jilin Province from June to November 2021.PCR was used to detect the pathogens of Boca Virus,Hanta Virus,Typhus group rickettsias,Yersinia pestis,Leptospira,Bartonella and Borrelia burgdorferi.After verification by Seq Man Pro of the DNASTAR software package,the sequencing results of PCR products were uploaded to Gen Bank for Blast analysis.The analysis of the genetic evolution tree and genetic distance was performed by Mega 11.0 software.Carriage rates of pathogens were compared across regions,habitats,and rodent species using chi-square tests.Results:A total of 484 mice of 9 species were captured in Yanji,Hunchun,Baishan,and Tonghua in Jilin Province,including 278(57.44%)Apodemus agrarius,130(26.86%)Rattus norvegicus,13(2.69%)Mus musculus,23(4.75%)Apodemus peninsulae,29(5.99%)Tscherskia triton,1(0.21%)Cricetulus longicaudatus,1(0.21%)Meriones unguiculatus,1(0.21%)Tamias sibiricus,and 8(1.65%)Myodes rufocanus.In addition,6 rats cannot be identified by morphology.Eight fleas which were identified as 2 species,3 genera,3 families were detected,including: 2(25%)C.(Euctenophthalmus)congeneroides-congeneroides Wagner,1930,2(25%)N.bidentatiformis(Wangen 1893),4(50%)Monopsyllus anisus Rothschild1907.13(2.65%)Boca virus,2(0.41%)Bartonella,9(1.84%)Leptospira and 8(1.63%)Hantavirus were identified from 490 rats.None of Typhus group rickettsias,Yersinia pestis and Borrelia burgdorferi was detected.Three pathogens were detected in 153 rats in Hunchun: Bartonella(2 cases,positive rate 1.31%),Leptospira(1 case,positive rate 0.65%),and Hantavirus(1 case,positive rate 0.65%,SEO type).Two kinds of pathogens were detected in 95 rats in Tonghua: Boca virus(13 cases,positive rate 13.68%)and hantavirus(1 case,positive rate 1.05%,).Two pathogens were detected in 146 rats in Changbai: Leptospira(8 cases,positive rate of 5.48%)and hantavirus(6 cases,positive rate of 4.11%).None of 7pathogens was detected in 96 rats in Yanji.The carriage rates of rodent pathogens in three regions,Hunchun,Tonghua and Yanji,were different and the differences were statistically significant(χ2 = 12.211,P = 0.002).Four pathogens were detected in 278 Apodemus agrarius: hantavirus(7 cases,positive rate 2.52%),Boca virus(6 cases,positive rate 2.16%),Bartonella(2 cases,positive rate 0.72%)and Leptospira(9 cases,positive rate 3.24%).Two pathogens were detected in 130 Rattus norvegicus: Hantavirus(1 case,positive rate 0.77%)and Boca virus(5 cases,positive rate 3.85%).Only one pathogen,the Boca virus,was detected in 13 Mus musculus(2 cases,positive rate 15.38%).No statistically significant differences in the carriage rates of pathogens in Apodemus agrarius,Rattus norvegicus and Mus musculus(χ2 = 3.193,P = 0.203).Conclusion:1.In 2021,four kinds of pathogens were detected in rats at the port area adjacent to DPRK in Jilin Province: Hantavirus,Bartonella,Leptospira,and Boka virus.Yersinia pestis,Borrelia burgdorferi and Typhus group rickettsias were not detected.There was no difference in the pathogen carrier rate of different rats in the port area adjacent to DPRK in Jilin Province.However,apodemus agrarius was the main rat that carried pathogens.Hantavirus,Bartonella,Leptospira,and Boka virus were all detected in apodemus agrarius,suggesting that apodemus agrarius was the host of various pathogens.Hantavirus is the most widely distributed pathogen,which has been detected in Hunchun,Tonghua,and Changbai.The Hantavirus in Changbai and Tonghua regions was HTN Hantavirus;however,the Hantavirus in Hunchun was SEO Hantavirus.Boca virus is the pathogen with the highest detection rate.2.In 2021,among Yanji,Hunchun,Baishan,and Tonghua,the rats in Tonghua had the highest pathogen carrier rate,and the species of pathogen carried by rats in Hunchun were the widest variety;however,the rats in Yanji did not carry any pathogens.The pathogen carrier rate of rats in the farmland was higher than that in the woodland and port living area of the port areas adjacent to DPRK in Jilin Province.