during september 2003 through may 2004 , serum samples were collected from 512 adult blood donors 1864 years old ( median 42 years ) and 188 children 24 years old . the blood donors were unpaid voluntary donors ; the children were hospitalized in toulouse for surgery or trauma . the prevalence of hev igg was determined by using the wantai hev igg enzyme immunoassay ( wantai biologic pharmacy enterprise , beijing , people s republic of china ) , according to the manufacturer s instructions . details of baseline demographic data and putative risk factors were collected from blood donors by using a structured questionnaire . in addition , to assess the risk for foodborne infection , we tested 18 local pig - liver sausages for hev rna using a quantitative real - time pcr based on the open reading frame 2 region of the hev genome ( 6 ) . hev igg was detected in 268 ( 52.5% ) of 512 ( 95% confidence interval [ ci ] 48.2%56.8% ) of the blood donors . the ranges of optical density / cutoff ratios for positive and negative samples showed a clear bimodal distribution ( figure 2 ) . of 244 rural donors , 63.1% ( 95% ci 57%69.2% ) were anti - hev positive compared with 42.9% ( 95% ci 3748.8 ) of 268 urban donors ( p<0.01 ) . for children , seroprevalence was 3.7% ( 95% ci 1.0%6.5% ) . the mean  sd optical density / cutoff ratio of the positive samples was 5.43  3.93 for children and 5.99  3.52 for adults . although several factors were associated with the presence of hev igg after univariate analysis , multivariate analysis identified only age , rural residence , hunting , and contact with cats as factors independently associated with hev igg positivity ( table 1 ) . prevalence of hepatitis e virus ( hev ) igg in 512 blood donors by age group , midi - pyrnes region , france , 20032004 . distribution of optical density / cut off ratios for hepatitis e virus igg in positive and negative samples from 512 blood donors , midi - pyrnes region , france , 20032004 . * hev , hepatitis e virus ; ci , confidence interval ; ns , not significant . hev rna was found in 8 ( 44% ) of the 18 sausages tested by real - time pcr ( table 2 ) . the virus load ranged from 100 ( the limit of detection for this assay ) to 668,520 copies / g . positive samples by sequencing a 189-nt fragment of the open reading frame 2 gene ( 7 ) . hev , hepatitis e virus ; na , no pcr amplification with primers used for genotyping . we determined that the hev igg prevalence among blood donors in midi - pyrnes is 52.5% , the highest seroprevalence reported in an industrialized country . this rate is 3.1 times higher than our previous estimate ( 16.6% ) for the same population ( 2 ) . although surprising , we believe these results are valid for several reasons . first , the wantai assay used to assess hev seroprevalence has been validated for this purpose in the united kingdom , another region where hev-3 predominates ( 5 ) . the greater proportion of reactive serum seen with this assay is unlikely to have resulted from nonspecific reactivity because the assay produced a clear distinction between negative and positive samples , and only a small proportion of young children tested positive . our findings agree with those of another study that found a much increased hev seroprevalence when the more accurate test was used ( 5 ) . . the estimated rate of acquisition of hev infection in organ transplant recipients in toulouse is 3.2 per 100 person - years ( 8) . this figure is derived from regular monitoring by using sensitive molecular techniques and does not depend on serologic assays . as noted in other countries ( 9,10 ) , the percentage of hev - positive serum increased with age , which is consistent with cumulative exposure to infection over time . hev is usually transmitted orally , and foodborne transmission of zoonotic strains has been demonstrated . hunting of wild boar and deer is popular in midi - pyrnes , particularly in rural areas . the consumption of uncooked game meat , which is traditional in this area , could explain the high hev antibody prevalence in 20 ( 80% ) of 25 hunters . further evidence comes from a case  control study among organ transplant recipients in midi - pyrnes that demonstrated that the only factor independently associated with hev infection was consumption of game meat ( 6 ) . some of these foods have been shown to contain hev rna , and phylogenetic analysis demonstrated that these strains were closely related to human strains ( 8) . another suspected zoonotic source of hev genotype 3 infection is the domestic pig ( 12 ) . hepatitis e cases have been linked to eating uncooked pork - liver sausage in southeastern france ( 13 ) . we found that a high proportion ( 44% ) of pig - liver sausages purchased in toulouse contained hev rna . these air - dried sausages are popular in midi - pyrnes and are usually eaten raw . their infectivity is unknown , but cell - culture experiments have demonstrated that high virus loads correlate with high infectivity ( 14 ) . in addition to direct foodborne transmission , the growing boar population in midi - pyrnes and the spreading of pig manure on land may pose indirect risks through fecal contamination of soil and watercourses . these 2 factors and the 2 foodborne sources of hev might explain the high hev antibody prevalence in midi - pyrnes and the statistical association of hev seropositivity with rural residence and hunting , but they can not explain the association with cat contact . hev rna has not yet been detected in domestic cats . the high percentage of donors with hev antibodies in our area contrasts with the low recorded incidence of autochthonous hepatitis e in france and other industrialized countries ( 1,15 ) . even though we documented dozens of hepatitis e cases in midi - pyrnes during the past decade , the remarkably high seroprevalence in this area suggests that most infections must be subclinical or unrecognized . however , in susceptible persons , such as organ transplant recipients and patients with chronic liver disease , the consequences of hev infection are grave and raise public health , as well as food and environmental safety , concerns . we showed that seroprevalence increases with age and is associated with rural residence , hunting , and exposure to cats . these associations became apparent only when we used a sensitive assay to detect hev igg . the reasons for the high hev prevalence in this population are uncertain but may be due , at least partially , to the culinary culture of the local community . thorough cooking of game meat and pork products would help minimize the risk for hev infection and could form part of a public health initiative in this area .