one of the most important helminthic diseases is hydatidosis or cystic echinococcosis , established via ingesting parasite s egg through soil , air , vegetable , contacting with dog etc . unilocoular cyst ( produced by echinococcus granulosus ) and multilocular cyst ( produced by e. multilocularis , respectively ) are among the most important human diseases in terms of imposed dalys and economic damages ( 2 , 3 ) . has estimated the number of asymptomatic individuals living in iran as 635,232 , in addition to overall annual cost of cystic echinococcosis as us$93.39 million ( 4 ) . as for livestock , iran has been considered as a country of endemic situation by who and various researches attested this claim ( 57 ) . so far , many studies have been conducted in different parts of iran to show the seroprevalence of human hydatidosis . accordingly , the rate of prevalence has been reported from 1.2% to 13.7% in different provinces ( 6 , 812 ) . iran has ideal situation in terms of the risk of infecting with hydatidosis such as the high rate of dogs infected with e. granulosus , food habit of eating row vegetable , presence of nomads in southern provinces , dusts etc . hence , it is of great importance to monitor the situation of human hydatidosis regularly throughout the country . although many diagnostic tests have been evaluated and established to diagnose hydatidosis , ( 1 , 1517 ) , but in iran mostly elisa test using agb has been reported as an authentic and valuable test for this issue ( 6 ) . elisa has the potential to be served as a vehicle to detect the seroprevalence of some diseases , so it was utilized in this study to detect the hydatidosis in isfahan province , central iran . the aim of this study was to determine the prevalence of human hydatidosis using elisa test in isfahan province , central iran . 1 ) . location of isfahan province in iran overall , 635 serum samples were collected from 20 health centers of isfahan city , and 10 centers from suburb areas . according to the statistician consultant , because population of the city is higher than in rural areas , 468 samples were collected from the city and 167 from rural areas . based on a random sampling all participants filled out an informed consent . besides , a questionnaire including information on food diet , vegetable consumption , clinical symptoms etc . was filled out for each case . in case of inability of the participant to fill out the questioner or informed consent form for any reason , the study was approved by the ethics committee of tehran university of medical sciences , tehran , iran . , hydatid cyst fluid ( hcf ag ) was aspirated from hydatid cysts obtained from livers and lungs of sheep slaughtered at the local abattoirs of tehran . antigen b was purified and extracted as described earlier ( 18 ) and was applied in elisa test . elisa test was performed in 96 well micro plates ( nunc , denmark ) as previously described ( 18 ) , with some modifications . micro plate wells were coated overnight at 4 c with 100 l agb ( 10 g / ml ) in 0.05 m bicarbonate buffer , ph 9.6 . wells were washed 3 times in pbs plus 0.05% tween 20 ( pbs - t ) and blocked with pbs - t containing 1% bsa for 30 min at 37 c . sera were added at 1:500 dilutions in pbst , incubated at 37 c for 1 h then washed as before . antihuman igg -hrp ( sigma chemical co. , poole , dorset , united kingdom ) conjugates were added at 1 : 10000 dilutions in pbs - t and the micro plate incubated and washed as before . this was then developed by opd substrate ( 5 mg 1 , 2-phenylenediamine , 12.5 ml of 0.2 m citrate phosphate buffer ph 5 , 10 l 30% h2o2 ) . the absorbance was read at 492 nm after 10 min using an automatic micro plate reader ( state fax 2100 , awareness , usa ) . altogether 30 samples of sera from healthy volunteers had been collected during the previous studies were examined to set the cut - off . 1 ) . location of isfahan province in iran overall , 635 serum samples were collected from 20 health centers of isfahan city , and 10 centers from suburb areas . according to the statistician consultant , because population of the city is higher than in rural areas , 468 samples were collected from the city and 167 from rural areas . based on a random sampling all participants filled out an informed consent . besides , a questionnaire including information on food diet , vegetable consumption , clinical symptoms etc . was filled out for each case . in case of inability of the participant to fill out the questioner or informed consent form for any reason , the study was approved by the ethics committee of tehran university of medical sciences , tehran , iran . at first , hydatid cyst fluid ( hcf ag ) was aspirated from hydatid cysts obtained from livers and lungs of sheep slaughtered at the local abattoirs of tehran . antigen b was purified and extracted as described earlier ( 18 ) and was applied in elisa test . elisa test was performed in 96 well micro plates ( nunc , denmark ) as previously described ( 18 ) , with some modifications . micro plate wells were coated overnight at 4 c with 100 l agb ( 10 g / ml ) in 0.05 m bicarbonate buffer , ph 9.6 . wells were washed 3 times in pbs plus 0.05% tween 20 ( pbs - t ) and blocked with pbs - t containing 1% bsa for 30 min at 37 c . sera were added at 1:500 dilutions in pbst , incubated at 37 c for 1 h then washed as before . antihuman igg -hrp ( sigma chemical co. , poole , dorset , united kingdom ) conjugates were added at 1 : 10000 dilutions in pbs - t and the micro plate incubated and washed as before . this was then developed by opd substrate ( 5 mg 1 , 2-phenylenediamine , 12.5 ml of 0.2 m citrate phosphate buffer ph 5 , 10 l 30% h2o2 ) . the absorbance was read at 492 nm after 10 min using an automatic micro plate reader ( state fax 2100 , awareness , usa ) . altogether 30 samples of sera from healthy volunteers had been collected during the previous studies were examined to set the cut - off . the result of seroprevalence study of human hydatidosis was detected as 1.1% ( 7 cases ) by elisa test in isfahan province ( fig . cut - off was calculated as 0.19 , so each od absorbance higher than this rate was considered positive . analysis of sera from subjects and normal controls from isfahan city and suburb areas , isfahan province , central iran by igg - elisa using antigen b. serum samples obtained from subjects ( 635 , lanes 1 ) , and normal controls ( 30 , lanes 2 ) the sero - prevalence of hydatidosis was 0.27% among females and 2.24% among males ( p=0.019 ) . age group of 6069 years old , with 2.59% as prevalence had the highest rate of positivity . there was no significant difference as regards age groups , job , residency , contact by dog and literacy . according to job , as regards residency , urban life ( 1.49% ) showed no significant difference with rural life . table 1 shows the distribution of age group among cases examined by elisa text in isfahan city and suburb areas for hydatidosis . distribution of positive cases of hydatidosis using elisa according to age group ( yr ) in isfahan city and suburb areas , isfahan province , central iran in this study , we detected a seroprevalence for human hydatidosis using elisa test in isfahan city and suburb area , accordingly total prevalence of human hydatidosis was 1.1% ( 7 cases ) . due to long time of prepatent period of human hydatidosis , and the risk of death after consecutive surgeries , it is regarded as one the most important parasitic disease throughout the world . iran for a long time has been considered as an endemic area for this disease and before considering a watch and wait method to monitor the disease , altogether 1% of all surgeries in iran belonged to hydatidosis ( 6 , 7 , 19 ) . the annual incidence in iran from various cities are as follows : hamadan 1.33/100000 ( 20 ) , kashan ( isfahan ) 3/100000 ( 8) , babol 1.18/100000 ( 21 ) and entire of iran 0.61/100000 ( 22 ) . many studies have been conducted so far to detect the rate of human hydatidosis in various parts of iran . accordingly the rate of infection has been reported as zanjan 3% ( 23 ) , nomads tribes from south of iran 13.7% ( 24 ) , ilam 1.2% ( 25 ) , kashan 2.04% ( 8) , sanandaj 7.3% ( 26 ) , golestan 2.34% ( 9 ) , meshkinshahr 1.79% ( 10 ) , tehran 1.63% ( 27 ) and qom 1.6% ( 28 ) . the rate of infection in our study was 1.1% , which shows more or less a similar rate with other parts of iran . in this study , the highest rate of infection was in the age group of 6069 yr old ( 2.59% ) . it is obvious that hydatidosis is a disease of long prepatent period and nearly most cases are diagnosed after a long time , so finding the most cases in higher ages is expectable ( 29 ) . previous studies reported the highest rate of infection in 6090 yr old in meshkinshahr ( 10 ) , 3060 yr in qomand and golestan ( 9 , 28 ) , 2030 yr in shahryar ( 12 ) , 4049 in arak ( 11 ) , and > 60 yr in mongolia ( 30 ) . in our study previous studies in iran shows nearly contradict findings in this regard , which originates from the culture and habit of people in different areas . some studies have reported more seropositivity in females than males ( 9 , 10 , 28 , 31 ) , but some studies reported invers results ( 10 , 32 ) , and one study has reported the same findings , i.e. , equivalence in males and females ( 33 ) . sources of infection with hydatidosis are varies such as soil , contact with dog , eating vegetable , etc . , so depending the culture and geographical situation the risk for infection would vary between males and females . for example , in villages where females have more contact with soil and intend to geophagy because of pregnancy , so they encompass more chance to get the disease ( 5 , 6 ) . considering occupation , we noticed no obvious difference between seropositive cases , which might be due to low sample , but many studies conducted in iran and abroad have reported mare seropositivity in housewives and farmers than other jobs ( 57 ) . in this study , illiterates showed the highest rate of infection ( 4 cases ) , which is attested by other studies as well ( 9 , 28 , 34 ) . as for residency in the city and rural areas , more all seropositive cases belonged to city . one of the most important limitations of this study might be mentioned as the low rate of sero - positive cases , which is a hinder in statistical analysis , but it would undoubtedly assist for conducting a systematic review and meta - analysis article . this study would help to complete the puzzle of determining the situation of human hydatidosis in different parts of iran . although the rate of infection was not high in isfahan city in this study , but it should be considered as a challenge in establishing the backbone of healthy measurements . ethical issues ( including plagiarism , informed consent , misconduct , data fabrication and/or falsification , double publication and/or submission , redundancy , etc . ) have been completely observed by the authors .
background : the aim of this study was to conduct a sero - epidemiological survey in isfahan city and suburb areas , central iran to detect the rate of human hydatidosis using elisa test.methods:overall , 635 serum samples were collected from subjects referred to different health centers in urban and rural regions of the city . 
 sera were analyzed using ag - b elisa test . 
 ten g / ml antigens , serum dilutions of 1:500 and conjugate anti - human coombs with 1:10000 dilutions were utilized to perform the test . 
 all subjects filled out a questionnaire and an informed consent . 
 data analysis was conducted using spss 18 software . 
 cut - off was calculated as x+3 sd.results:cut-off value was calculated 0.19 . 
 seven cases ( 1.1% ) were seropositive for hydatidosis by elisa test . 
 the sero - prevalence of hydatidosis was 0.27% among females and 2.24% among males ( p=0.019 ) . 
 age group of 6069 years old , with 2.59% as prevalence had the highest rate of positivity . 
 there was no significant difference as regards age groups , job , residency , contact by dog and literacy . according to job 
 , self - employed people had the highest rate of infection as 3.05% . 
 the sero - prevalence of infection was 1.14% in diploma and 1.13% in illiterates . 
 as regards residency , urban life ( 1.49% ) showed no significant difference with rural life.conclusion:the rate of prevalence in this region showed that necessary cautions should be taken into account to monitor the spread of human hydatidosis in this region . in comparison with other studies , 
 the rate of infection was roughly less than other regions .