Serological diagnosis and molecular epidemiological analysis of rickettsiosis in Lu'an,Anhui Province,China
Objective From May 2017 to November 2021,there was an increased number of cases of fever with rashes admitted to Huoshan County Hospital in Lu'an City,Anhui Province,China.The aim of the study is to find out the etiology of the patients through epidemiological and clinical characteristic analysis,so as to provide a scientific basis for the prevention and control of the febrile illness with rashes.Methods An epidemiological investigation was carried out on the cases of fever with rashes through inquiring their medical histories and reviewing their medical records.The acute sera at admission and convalescent sera were collected from the patients to examine IgG antibody titers to Anaplasma,Borrelia burgdorferi,Orientia,Ehrlichia,Rickettsia rickettsii,and R.typhi using indirect immunofluorescence assay.An infection of a pathogen was determined by a 4-fold increase of the serum IgG antibody titer to the pathogen between the acute serum and the convalescent serum.The etiologic agent causing the outbreak was further identified by PCR amplification and DNA sequences of the rickettsial genes from acute serum.Results The IgG antibodies to Anaplasma,B.burgdorferi,and R.typhi were all negative in the acute sera of the patients.The positive rate of serum IgG antibodies to R.rickettsii was 51.52%(68/132)in the acute sera and 89.19%(33/37)in the convalescent sera.In the paired sera,the IgG titer had more than four time increase in the acute sera than in the convalescent sera.Phylogenetic analysis with the Rickettsia ompA sequence indicated that the etiologic agent formed a monoclade with newly identified Candidatus R.jingxinensis in Yunnan,China.Conclusion The febrile cases with rashes in Lu'an were serologically diagnosed as spotted fever rickettsial infection.
NETL
NSTL
万方数据
