| Objective: To screen for tick-borne infections in the population in Liaoning Province.To conduct an epidemiological survey of screened tick-borne infectious diseases,collect specific clinical manifestations of tick-borne infectious disease cases,and provide a basis for the diagnosis and treatment of tick-borne infectious diseases.Methods: In this study,the First Affiliated Hospital of China Medical University and the Liaoning CDC were selected as the sample sources,and strict inclusion criteria were established based on the epidemiological characteristics and clinical manifestations of tick-borne infectious diseases,blood samples and clinical data of suspected patients were collected,and epidemiologically relevant information such as onset,exposure history and contact history of the included cases were obtained.The collected blood samples were processed into serum samples in a timely manner and stored with numbers,and pathogenic nucleic acids were extracted from the blood samples according to the steps of the kit.In this study,a tick-borne pathogen Taq Man Array Card detection system was used to detect all blood samples in this study for tick-borne pathogens,including SFTSV,SFGR,Coxiella burnetiid,Borrelia burgdorferi sensu lato,Anaplasma phagocytophilum,Ehrlichia,Babesia and Francisella tularensis.The pathogens with positive screening results were amplified and then sequenced for specific gene fragments,and the sequencing results were compared and analyzed to establish an evolutionary developmental tree.Results: From 2018 to 2022,a total of 398 cases were included in this study,and the sample source covered all 14 prefectures under Liaoning province,and 255 patients with tick-borne pathogens infections were finally detected,including 236 cases of SFTS,13 cases of SFGR infection,5 cases of Q fever,and 1 case of HGA.One of the cases was a mixed SFTSV and SFGR infection.(1)SFTS infection: A total of 236 positive cases were screened,with an overall increasing trend of severe disease rate(Z=2.2045,P<0.05)and an overall decreasing trend of morbidity and mortality rate(Z=-2.2045,P<0.05).The mean age of the patients was 63.65±12.18 years,the gender ratio of patients was 0.94:1,and the majority of patients were farmers(77.5%).The peak incidence period was June to September.All cases were disseminated,with a clear history of tick bite in 80 patients(33.90%)and a history of field activities or animal contact in all other patients.The incidence areas were mainly in Dalian,Dandong and Yingkou.(2)SFGR infection: A total of 13 positive cases were screened,and after sequencing and analysis,the final cases were one case of infection with R.parkeri strain Atlantic rainforest,one case of infection with Rickettsia felis,and 11 cases of infection with the provisional strain of Candidatus R.jingxinensis.The mean age of the patients was 49.54±14.72 years,the male to female sex ratio was 1.6:1,and the majority of the patients were farmers.The onset of spot fever was from May to October,with a peak in June.Geographic distribution was mainly concentrated in Dandong City.The clinical manifestations were mainly fever with malaise,headache,rash,and diarrhea.White blood cell and platelet counts are reduced.(3)Q fever infection: A total of 5 positive cases were screened,among which 3 patients were over 70 years old.The onset of Q fever was from June to October,with the most frequent in July.The incidence area was mainly in Anshan City.The clinical manifestation can be chronic Q fever infective endocarditis and acute Q fever "flu-like" manifestation,which can be combined with pneumonia.Severe cases can be complicated by multi-organ failure and death.The white blood cell count is mostly normal and the platelet count is low.(4)HGA infection: One positive case was screened,a middle-aged male,starting in October,living in Dandong City.The clinical presentation was fever with peripheral pain,dizziness and nausea.The white blood cell and platelet counts were decreased and the percentage of neutrophils was progressively and substantially decreased.(5)Mixed infection: one case of mixed infection of SFTSV and SFGR Candidatus R.jingxinensis was screened in this study.The clinical presentation was fever with malaise,headache,arthralgia,nausea,and scattered hemorrhagic spots on the skin,combined with secondary hemophagocytic syndrome.Conclusion: 1.In this study,the pathogenicity of Candidatus R.jingxinensis in humans was confirmed for the first time and 11 cases of Candidatus R.jingxinensis infection were found,including an co-infection of SFTSV and Candidatus R.jingxinensis.The infection of Rickettsia felis,Q fever,Anaplasma phagocytophilum was detected in Liaoning Province for the first time.Therefore,the possibility of infection by tick-borne pathogens other than SFTSV needs to be considered for infected patients whose pathogens cannot be identified by routine laboratory tests in Liaoning Province and other natural epidemic sites of tick-borne infectious diseases in China.2.Clinical manifestations of tick-borne infectious diseases are mostly nonspecific systemic reactions,commonly fever,malaise,nausea,diarrhea,dizziness,headache,and generalized muscle and joint pain.Laboratory tests may include decreased white blood cell,platelet and neutrophil counts.Severe patients may die from multiple organ failure.3.From 2018 to 2022,the SFTS fatality rate in Liaoning Province showed an overall decreasing trend,but the rate of severe illness showed an overall increasing trend. |
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