Epidemiologic analysis on five cases involved in an outbreak of anthrax in a village of Wengan County,Guizhou, China / 中国人兽共患病学报

ABSTRACT

We identified the routes of infection and evaluate the effect of disinfection on the field of an outbreak of an-thrax in a village of Wengan County ,Guizhou ,China ,thus trying to provide with basis for the implementation of policies for pre-vention and control of anthrax .The authors gathered the cases information by searching and interviewing the targeted persons house by house ,and reviewed the medical records in hospitals .The samples including patient’s discharging fluid ,residues of died horse ,and soil from the places where the villagers dismembered horse were gathered and cultured for Bacillus anthracis . The technique of multiple-locus variable-number tandem repeat analysis (MLVA-8) was applied for revealing the genetic rela-tionships among those isolated Bacillus anthracis strains .Five cases of cutaneous anthrax occurred in the outbreak and the total attack rate was 7 .58% (5/66) among those contactors evolved in the activity of carrying ,dismembering ,washing ,chopping and eating the died horse .The attack rate was 100% (3/3) for those who carried ,dismembered ,washed ,chopped and ate that horse ,100% (1/1) for those who carried ,dismembered and ate ,and 7 .14% (1/14) for those who washed ,chopped and ate . The 25% (1/4) of the samples of discharging fluid from the cases with cutaneous anthrax were positive .After disinfection , 15 .38% (4/26) of the soil samples retained positive .The genetic similarity was 100% among the 5 isolate strains .The results suggested that the outbreak of anthrax in villagers occurred through the activities of carrying ,dismembering ,washing and chop-ping the died horse .Strengthening the risk communication and disinfection of the dismemberment places should be the crucial strategies to prevent and control anthrax epidemics in Guizhou in the future .