The Epidemiological Characteristics And Animal Models Of Crayfish-related Rhabdomyolysis Syndrome

Background:Haff disease is an unexplained rhabdomyolysis(Rhabdomyolysis,RM)caused by eating cooked freshwater and seawater aquatic products.Cases in our country are mostly caused by eating crayfish.Since the summer of 2010,there were several cases reported,with the most cases in 2016,which caused widespread social concern.However,the etiology of Haff disease is still unclear.The systematic research on the epidemiological characteristics and influencing factors of Haff disease caused by crayfish in our country is limited,and animal experiments have not obtained clear etiological clues.Objective:To summarize the epidemiological characteristics and influencing factors by reviewing the previous cases and the epidemiological investigation of the new cases of crayfish related RM in 2019.Explore the occurrence of RM in laboratory animals with known RM-causing substances to select the animal with similar pathogenic characteristics and clinical manifestations of crayfish-related RM.Use the samples collected from the suspicious food traceability investigation of new cases to conduct animal experiments,and screen the suspicous samples containing pathogenic factors.To establish a method for screening suspicious food samples in animal experiments.Methods:We conducted a systematic literature study on cases of Haff disease,selected provinces and cities with high incidence of RM to carry out epidemiological investigations on new cases to clarify the epidemiological characteristics of disease.Combined with previous investigations and etiology hypotheses,we collected information on related risk factors such as crayfish exposure history,field catch points,etc.and conducted case-control studies to discover the influencing factors of the disease.Using known drugs that can cause human rhabdomyolysis in animals of different species and lines to select appropriate animals with similar pathogenic characteristics and clinical manifestations of human Haff disease.On the basis of epidemiological research,we administered crayfish samples related to cases to laboratory animals,the serum levels of Creatine Kinase,Myoglobin and Alanine aminotransferase,Aspartate aminotransferase were tested bofere and after adminstation.Tissue samples from skeletal muscle were stained with hematoxylin and eosin(HE)and were observed under a microscope for routine pathological examination.Results:(1)There were 1606 crayfish-related cases reported in the literature and 188 related to other aquatic products.Crayfish-related RM cases occur in cities in the Yangtze River Basin in China in July and August each year,with high incidence among young women.The prevalence of other aquatic product-related cases has no obvious seasonal characteristics and population distribution characteristics.From July 1,2019 to August 23,2019,a total of 45 cases of crayfish-related rhabdomyolysis were collected from Wuhan City,Hubei Province and Ma’anshan City,Anhui Province,including 32 confirmed cases,5 probable cases,and 8 suspected cases.Myalgia(n=45,100.00%),muscle weakness(n=31,68.89%)and chest tightness(n=23,51.11%)were the most common symptoms.Laboratory tests showed elevated creatine kinase,up to 17432U/L.The age of cases was concentrated in 20-50 years old,female cases were slightly more than male cases.All cases were fed crayfish before the onset of disease.The interval between the last meal and the onset was 8h(range 2h-15h).The average amount of crayfish taken by cases was 16 pieces(500g),they mainly ate the muscle of crayfish(91.09%)and the hepatopancreas(86.67%).A case control survey of cases and non-diseased persons taken the same crayfish with cases found that there was a statistically significant difference between the number of crayfish eaten(OR=1.23(1.07,1.40))and whether they eat hepatopancreas(OR=18.24(2.80,118.87))between the case group and the control group.(2)Serum CK,AST,ALT increased in Wistar rats after 10 consecutive days of co-administration of simvastatin and gemfibrozil compared with baseline(P<0.05).Pathological examination of muscle tissue of individual rats showed muscle fiber necrosis.After co-administration of simvastatin and gemfibrozil or single administration of ICR mice,there was no statistically significant difference in the biochemical indexes compared with the control group and before administration.Wistar rats can be used in the crayfish-related RM animal experiment.The crayfish samples collected from the source investigation(case ID:420103-001-1)were divided into three parts:musle,hepatopancreas,and gills,fed Wistar rats after cooking or not.Continuous administration of raw and cooked muscle of crayfish,the serum CK and AST of rats were increased on the 5th and 10th days,and the activity of the rats was reduced.Continuous administration of raw and cooked hepatopancreas,on the 5th day,serum CK,AST increased.It is suggested that this crayfish samples may contain a factor that causes RM.This factor is mainly present in muscle and hepatopancreas,and the content in each piece of crayfish may be different,the content in muscle and hepatopancreas may be different.The factor is heat-stable.Conclusion:Crayfish-related RM is popular in cities in the Yangtze River Valley in July and August every year in China.The incidence in young women who like to eat crayfish is high.Large amounts of muscle and hepatopancreas are possible risk factors;Wistar rats can develop RM after co-administration of simvastatin and gemfibrozil,which is appropriate animal in studies on Haff disease;crayfish samples related to cases caused RM in rats.Muscle and hepatopancreas of crayfhis may contain RM-causing hazards.Hazardous materials are thermally stable.