Epidemiological investigation on an outbreak of autumn tsutsugamushi disease in Taizhou region of Jiangsu Province / 中华传染病杂志

ABSTRACT

Objective To analyze the epidemiological and clinical characteristics of an outbreak of tsutsugamushi disease in Taizhou region of Jiangsu Province,and to clarify new changes of endemic focus of tsutsugamushi disease in Jiangsu Province.Methods The definition of tsutsugamushi infected cases was determined,field epidemiological investigation with analysis of clinical features and polymerase chain reaction (PCR) results to diagnose tsutsugamushi disease were combined.Some of the positive samples were conducted genotyping by amplification and sequencing.Results The outbreak occurred from October to November,2011.The endemic focus located on the plain with humid climate and abundant rainfall.Fifteen cases of tsutsugamushi disease were found,including 6 PCR confirmed cases,5 clinically diagnosed cases,and 4 suspected cases.The main clinical symptoms were fever in 15 cases,skin rash in 14 cases,lymphadenectasis in 3 cases,skin eschar or ulcer in 12 cases,and liver dysfunction in 3 cases.None of the patients developed severe complications,and all recovered rapidly after the treatment.Comparing the sequencing results of positive samples with standard strains,the homology of base sequences was 99.00％ with that of Kawasaki.Conclusions The outbreak of tsutsugamushi disease in Jiangsu Province in 2011 is of autumn type in transitional endemic focus,and the pathogen is Kawasaki Orientia tsutsugamushi.