| Objective:Explore the possibility of Blastocystis spreading between family members and between family members and domestic animals,by understanding the infection and genetic polymorphisms of Blastocystis in elementary school students and their family members and domestic animals.Provide a reference for the prevention and control of Blastocystis in local populations and animals.Methods:In June 2020,a cross-sectional survey method was used to conduct a questionnaire survey on primary school pupils in grades 3 to 5 of a primary school in Jiangjin District,Chongqing.Logistic regression model was used to analyze the influencing factors of Blastocystis infection in primary school pupils,and SPSS 25.0 software was used for statistical analysis.Collect fresh stool samples from primary school students,extract genomic DNA from stool samples,apply PCR method for nucleic acid detection,obtain amplified sequences at the same time,splice and compare the sequences,and construct a phylogenetic tree.The sequence was assembled using the SeqMan program of DNAStar software,and the MEGA5.0 software was used for sequence comparison and a phylogenetic tree was constructed to confirm the infection status and subtype distribution of Blastocystis in primary school students.From June 2020 to August 2020,using a case-control study method,the cross-sectional survey of primary and middle school students who were positive for Blastocystis as the case group,matched the corresponding Blastocystis negative among the primary school students as the control group.Household surveys were used to conduct questionnaire surveys on the family members of the case group and the control group,and the χ2 test or Fisher exact probability method was used to analyze the economic status,education level and hygiene habits of the two groups of family members.Collect stool samples from family members and domestic animals in the case group and the control group,extract the genomic DNA of the stool samples,apply PCR method for nucleic acid detection,obtain the amplified sequence at the same time,splice and compare the sequences,construct a phylogenetic tree,and understand the current status and subtype distribution of Blastocystis infection of two groups in family members and domestic animals.The χ2 test or Fisher’s exact probability method was used to compare the infection of Blastocystis in family members and domestic animals in the case group and the control group.Statistical analysis uses SPSS 25.0 software.Results:A total of 427 primary school students were investigated,including 214 boys and 213 girls.The average age was(10.42±0.971)years.The infection rate of Blastocystis was 7.49%(32/427).Among them,the infection rate of boys was 7.9%(17/214),and that of girls was 7.0%(15/213).There was no statistically significant difference between male and female Blastocystis infection rates(χ2=0.125,P=0.723).The infection rate of Blastocystis among pupils living in rural areas was 7.2%,and that of urban pupils was 8.8%.The difference in infection rate of Blastocystis between the two groups was not statistically significant(χ2=0.224,P=0.636).The infection rate of Blastocystis among students of different race(χ2=0.001,P=1.000)and different grades(χ2=1.438,P=0.487)was not statistically significant.There was no statistically significant difference between Blastocystis-infected and non-infected people:the type of daily drinking water(χ2=0.044,P=0.834),whether to wash hands after going to the toilet(χ2=2.522,P=0.112),whether to keep pets at home(χ2=0.013,P=0.908),whether to raise livestock at home(χ2=3.066,P=0.080),etc.It was also shown that non-water flushing toilet(OR=2.256,95%CI:1.007,5.053)was the influencing factor of Blastocystis infection in primary school students in single factor analysis and multivariate logistic regression analysis.The clinical symptoms of diarrhea,nausea,vomiting,abdominal distension,fever,loss of appetite,and fatigue were not statistically significant between Blastocystis-infected and non-infected patients.The primary school students were infected with four subtypes:ST1,ST3,ST4,and ST6,of which ST3 was the most 71.9%(23/32),followed by ST1(18.8%,6/32),ST4 and ST6 were 1(3.1%)and 2(6.2%)cases.This study investigated 92 family members in 32 families in the case group.There were 26,29,28,and 10 family members with parents,grandparents,siblings,and other relationships in the case group,respectively.82 family members in 32 families in the case group control.There were 32,26,23,and 1 family members with parents,grandparents,siblings,and other relationships with the control group,respectively.The infection rate of Blastocystis in family members in the case group was 10.87%(10/92).There was no Blastocystis infection in family members in the control group.The difference between the two groups was statistically significant(P<0.05).The infection rate of siblings among family members of the case group was 17.9%(5/28),followed by 15.4%(4/26)of parents.The difference in infection rates of different family members was not statistically significant(χ2=4.280,P=0.196).There are three subtypes of family members infected with Blastocystis:10%are ST1(1),70%are ST3(7),20%are ST4(2),ST3 is the dominant genotype.No correlation was found between subtype and clinical symptoms.Among the primary school students and family members,the infected persons came from 32 families,and there were 8 families with 2 or more infected persons.Among them,all the infected persons in the 5 families had the same subtype.In this study,85 fecal samples of domestic animals(including livestock,poultry and pets)were collected from 32 case groups,including six species of animals chickens,ducks,pigs,geese,dogs,and cats.The fecal samples were 24,28,11,16,5 and 1,respectively.60 domestic animal feces samples were collected from 32 control families,including 6 species of chickens,ducks,pigs,geese,dogs,and cats.The fecal samples were 29,13,5,3,9 and 1,respectively.The detection rate of Blastocystis in domestic animals in the case group and the control group was 8.2%(7/85)and 8.3%(5/60),respectively.The difference in detection rate between the two groups was not statistically significant(P>0.05).The detection rate of chickens in the case group and control group was 12.5%(3/24)and 10.3%(3/29),respectively.The detection rate of ducks in the case group was 3.6%(1/28),and the control group had 15 duck feces no infection was found in the sample.The detection rate of pigs in the case group and the control group was 27.3%(3/11)and 40.0%(2/5),respectively.There was no statistically significant difference in the detection rate of chickens,ducks and pigs between the case group and the control group(P>0.05).Blastocystis was not detected in the stool samples of geese,dogs and cats in the case and control groups.The subtypes of chicken in the case group were:ST6(2),ST7(1),the control group were:ST6(1),ST7(2).The subtype of ducks in the case group was ST7(1).The subtype of pig infection in the case group was ST5(3),the control group was ST5(2).The two groups of domestic animals infected with subtypes include ST5(41.7%;5/12),ST6(25.0%;3/12)and ST7(33.3%;4/12),all three subtypes are zoonotic subtype.Among them,ST5 is the main subtype,which is only detected in pig feces samples.The subtypes of infected chickens are mainly ST6(50%,3/6)and ST7(50%,3/6).One case detected in ducks was positive and the subtype was ST7.Animal fecal samples infected with Blastocystis came from 10 families,and compared with the subtypes of family members in these 10 families,it was found that the family members were not consistent with the subtypes of domestic animals.Conclusion:The infection rate of Blastocystis in primary school students is relatively high(7.49%)in Jiangjin District,Chongqing China.The subtypes include ST1,ST3,ST4 and ST6,of which ST3 is at most 71.9%(23/32).Non-water flushing is the influencing factor for the infection of Blastocystis in local primary school students.The infection rate of Blastocystis in family members of the case group was significantly higher than the control group.The difference between the two groups was statistically significant,and all infected persons in the same family had the same subtype,suggesting that Blastocystis may spread among family members.In this investigation,only ST6 existed in both humans and domestic animals,but no consistent genotypes of family members and domestic animals were found in the same family,suggesting that Blastocystis is less likely to spread between family members and domestic animals.The results of this study can provide a reference for the prevention and control of Blastocystis in local populations and animals. |
PDF Full Text Request