[Seropositivity for human T-lymphotropic virus types I and II among donors at the Municipal Blood Bank of Caracas and associated risk factors].
OBJECTIVE
To conduct research at the Municipal Blood Bank of Caracas (MBBC) and find out the proportion of blood units discarded for being seropositive for human T-lymphotropic virus (HTLV) types I and II, the prevalence of that infection among their donors, and the probable risk factors for that infection among those HTLV-positive donors.


METHODS
ELISA serological testing was done with 23 413 donors seen at the MBBC between July 2000 and April 2001. Samples that were repeat reactive (RR) with the ELISA underwent supplementary Western blot (WB) testing. Donors who had a positive or indeterminate WB result were scheduled for counseling in order to carry out confirmatory testing using nucleic acid amplification (NAA), to collect data on their risk background, and to advise them concerning their HTLV status.


RESULTS
Of the 23 413 MBBC donors, 48 of them (0.2%) had a donation that was RR. Of those 48, 25 of them (52.1%) were positive on the WB (23 for HTLV-I and 2 for HTLV-II), 2 of them (4.1%) were indeterminate on the WB, 14 of them (29.2%) were negative, and 7 (14.6%) could not be evaluated. Of the 27 donors scheduled for counseling, 16 of them actually attended (14 WB-positive for HTLV-I, 1 WB-positive for HTLV-II, and 1 indeterminate). All 16 of them were positive with the confirmatory NAA testing. When these 16 seropositive donors were compared with a control group of seronegative donors, no significant differences were found with regard to age, sex, type of donation, number of previous donations, history of transfusions, and sexual behavior. However, significant differences were found in two areas: the seropositive donors were more likely to have used non-intravenous drugs (P < 0.05), and the seropositive donors were much more likely to have had an extended breast-feeding period (more than 2 years) as a child (P < 0.001). To assess the probability of mother-to-child transmission, six of the mothers of seropositive donors who had had an extended breast-feeding period were tested, and all six of those mothers were also found to be seropositive. With the 16 seropositive donors who were counseled, the spouse or partner of 13 of them was also tested; only 1 of those 13 was positive, but the oldest son of that couple was also HTLV-positive.


CONCLUSIONS
Of the donated blood, 0.2% of the units were discarded for being positive for HTLV-I or HTLV-II, and the prevalence found among the donors was 0.11%. Sexual transmission between an HTLV-positive donor and a partner or spouse was less frequent than was mother-to-child transmission. At present in Venezuela, blood banks are not required to screen donations for HTLV. Given our results at the MBBC, we believe serious consideration should be given to implementing serological screening for HTLV I/II among blood donors throughout Venezuela.
Banco Municipal de Sangre del Distrito Capital, Caracas, Venezuela. gonzaleo@cantv.net
Graciela
G
León
Ana M
AM
Quirós
José L
JL
López
Meilyn
M
Hung
Ana M
AM
Díaz
Juvic
J
Goncalves
Osiris
O
Da Costa
Teodoro
T
Hernández
Merlin
M
Chirinos
Rafael
R
Gómez
D000328:Adult; D001771:Blood Banks / Q000458:organization & administration; D001782:Blood Donors; D006800:Deltaretrovirus Infections / Q000453:epidemiology / Q000821:virology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006679:HIV Seropositivity; D006773:Hospitals, Municipal; D015368:Human T-lymphotropic virus 1 / Q000302:isolation & purification*; D015367:Human T-lymphotropic virus 2 / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D014687:Venezuela / Q000453:epidemiology