blood donation in israel is voluntary and does not involve any monetary benefit . using records from magen david adom , we registered age , sex , country of birth , and maternal and paternal countries of birth once for each donor , regardless of the number of blood units donated . from 1995 through 1998
, donors were screened for antibodies against htlv-1 and htlv-2 by standard elisa ( abbott htlv-1/htlv-2 enzyme immunoassay ; abbott laboratories , abbott park , il , usa ) . since 1998
, testing has been performed by chemiluminescent immunoassay with the prism assay ( abbott laboratories ) .
the confirmatory assay was western blot htlv blot 2.4 ( genelabs diagnostics , singapore science park , singapore ) . on the basis of virus transmission modes
, we developed an algorithm for identifying the ethnic origin of both htlv-1positive and htlv-1negative blood donors ( figure 1 ) .
we considered infection to be acquired in israel when the donor and both parents were born in israel .
we considered infection to be acquired outside israel when the donor or 1 parent was born outside israel . when the donor was born in israel and
the mother was born outside israel , country of origin was considered the mother 's country of birth . when the donor and the mother were born in israel , but the father was born outside israel , country of origin was considered the father s country of birth .
detailed classification of geographic origin of blood donors ( both htlv-1 positive and htlv-1 negative ) is given in the technical appendix .
data were analyzed by using microsoft access ( microsoft , redmond , wa , usa ) and epi info ( centers for disease control and prevention , atlanta , ga , usa ) ; statistical analysis was conducted by using  analysis of contingency tables . the odds ratio ( or ) and 95% confidence interval were calculated .
the chaim sheba medical center human subjects research review board approved this study . from january 9 , 1995 , through december 31 , 2003
of these , 73 htlv-1 carriers were identified , for an overall prevalence of 5.8 infections per 100,000 donors .
average age at diagnosis was 39.4  11.9 years ; 48 ( 66% ) were men ( compared with 72% of all blood donors ; p = 0.3125 ) .
all htlv-1positive donors had negative serologic results for htlv-2 , human immunodeficiency virus , hepatitis c virus , and hepatitis b surface antigen .
donors from middle eastern and eastern european countries were at highest risk for htlv-1 carriage .
relative risk for human t - cell lymphotropic virus type 1 carriage in donors from different geographic origins .
error bars indicate 95% confidence intervals ( ci ) . * per 100,000 population ; p<0.05 .
the diversity of the population in israel , combined with systematic screening of blood donors , enabled us to examine the global epidemiology of htlv-1 infection .
one or both parents of at least 67% of jews in israel were born outside israel .
thirteen percent immigrated from asia , 16% from africa , and 36% from europe and the americas ( 3 ) .
we believe that blood donors are representative of healthy persons in the general population of the country because approximately one third of the population are blood donors .
the prevalence of htlv-1 infection among donors in israel was 5.8/100,000 but varied depending on donors geographic origins . in blood donors born in israel ,
the prevalence of htlv-1 infection was 1/100,000 , comparable to and even lower than the prevalence of htlv-1 in blood donors from northern europe ( technical appendix ) .
we found a similar prevalence of htlv-1 infection in jewish immigrants from known htlv-1 endemic countries to what is known in their native countries .
for example , the reported prevalence in blood donors in latin american countries ranged from 30/100,000 to 1,000/100,000 ( technical appendix ) ; our study found a prevalence of 20/100,000 . in donors from the middle east
, we found a high prevalence of htlv-1 infection in blood donors from iran ( 50.4/100,000 ) , turkey ( 16.0/100,000 ) , and iraq ( 10.2/100,000 ) .
of those countries , only iran can provide information about htlv-1 prevalence , and those data are limited to mashhad ( 4 ) .
our survey was performed after the initial report of htlv-1associated disorders in israelis born in or originating from mashhad ( 5 ) .
this example can highlight the role of immigrants as reflectors of the populations in their countries of origin .
we found no systematic information about the epidemiology of htlv-1 in the rest of iran and neighboring countries .
however , anecdotal reports suggest that the infection exists in kuwait , turkmenistan , and georgia ( 68 ) . in persons from eastern europe
, we found a high prevalence of htlv-1 carriage in blood donors originating from romania ( 14.9/100,000 ) , russia ( 6.3/100,000 ) , and the former yugoslavia ( 62.9/100,000 ) .
most of the literature does not consider eastern europe endemic for htlv-1 infection ( 2 ) . particularly in romania ,
htlv-1 prevalence is considered low , and htlv-1 positivity was attributed mainly to immigration from other countries ( 2 ) . in a careful review of the literature
, we found only a few studies involving a small number of blood donors ( technical appendix ) .
these studies support our findings and suggest that htlv-1 is endemic in some eastern european countries .
several cases of adult t - cell leukemia have been described in patients of romanian origin ( 914 ) .
our findings establish the need for rigorous screening of blood donors in suspected htlv-1endemic areas ( middle east and eastern europe ) and show the impact of immigrants or travelers as sentinels to the health problem in their country of origin .
our data also demonstrate high prevalence of htlv-1 infection among those whose country of origin had been considered nonendemic for htlv-1 .
viral transmission could have occurred either from the non - jewish local population or from other jewish communities in which htlv-1 is endemic .
we are not aware of immigration waves of jewish populations from iran and iraq to eastern europe and vice versa .
therefore , it seems reasonable to conclude that our findings reflect local htlv-1 endemicity in the country of origin .
 the prevalence of infection with human t - cell lymphotropic virus type 1 ( htlv-1 ) in blood donors from israel is 1 infection/100,000 persons . in donors originating from eastern 
 europe , the middle east , and latin america , prevalences are 7.7 , 14.6 , and 20.4 , respectively . 
 htlv-1 prevalence may be high outside areas where htlv-1 previously was known to be endemic . 
The Study
Conclusions
Supplementary Material