Restudy On Chromoblastomycosis In Zhangqiu Area Of Shandong Province After 40 Years

Research backgroundChromoblastomycosis(CBM)is a chronic infectious disease of skin and subcutaneous tissue caused by a group of dematiaceous fungi.The common pathogens are a group of dark fungi.The course of chromoblastomycosis is chronic.The patients with a long history may have canceration or contracture of joint deformity,which is stubborn and difficult to treat.The patients with a serious history may lead to disability and loss of labor.Because of the lack of typical clinical manifestations,chromoblastomycosis is difficult to diagnose,easy to relapse.And it seriously affects the quality of life of patients.The disease is reported worldwide,incidence of which is high in tropical and subtropical regions.In China,chromoblastomycosis has been found in 20 provinces and autonomous regions,most in Zhangqiu and its surrounding areas in Shandong Province,forming a local epidemic.40 years ago,dermatologists in Shandong provincial hospital found that the patients who were diagnosed with chromoblastomycosis were mainly from Zhangqiu and its surrounding areas.Therefore,an epidemiological survey of chromoblastomycosis was carried out in Zhangqiu area of Shandong Province for 6 years since 1975.The prevalence of the disease was 0.23‰.The study showed that the pus of chromoblastomycosis patients could pollute the surrounding environment.It was also found that 42.7%of the wild toads in Zhangqiu area were carrying the pathogenic fungi.After more than 40 years of reform and opening up,what is the situation of chromoblastomycosis in Zhangqiu after comprehensive treatment?Our research group has completed " Restudy on chromoblastomycosis in Zhangqiu area of Shandong Province after 40 years".Objective1.To understand the status and trends of the Chromoblastomycosis(CBM)in Zhangqiu area of Shandong province and to compare the morbidity with that in 40 years ago,to provide scientific basis for the control of chromoblastomycosis in Zhangqiu area.2.To understand the distribution of dematiaceous fungi in the environment of Zhangqiu,and to provide relevant basic information for the prevention and control of chromoblastomycosis in Zhangqiu.Methods1.Population based study:From September 2017 to February 2018,a total of 1016,591 residents in zhangqiu district,were diagnosed with chromoblastomycosis.Suspected cases were reported by primary doctors and dermatology graduate students through questionnaires.Attending and above dermatologists conducted pathogen examination and pathological examination to verify the diagnosis,and counted the cases of chromoblastomycosis in this area.2.Toad experiment:From July to September 2019,the amphibian toad was captured in groups in Zhangqiu area,which internal organs were taken to make suspension and centrifuged for residue,for the cultivation and sequencing identification of black fungi.Results1.Zhangqiu area has 21 towns,815 villages,and has a population of 844591 people of the rural area,and a population of 172000 people of the urban area.The current morbidity of chromoblastomycosis in Zhangqiu area is zero.2.There were 78 wild toads dissected,9 of which were cultured with the bacteria.The positive rate of the bacteria isolated from wild toads was 11.54%.The difference was statistically significant(?2=26.539,P<0.01),which was significantly lower than that of 40 years ago.Four black strains were successfully identified,which were Cladosporium tenuissimum,Exophiala spinifera,Phialophora verrucosa,Cladosporium cladosporioides.Conclusions1.The endemic disease——chromoblastomycosis in Zhangqiu area has been basically eliminated.2.At present,the positive rate of dark fungi isolated from wild toads in Zhangqiu area is 11.54%.The dominant pathogen of chromoblastomycosis in the north,Cladosporium carinii,has not been isolated.