Injection drug use (IDU) is a known risk factor for hepatitis C virus (HCV) infection, but the strength of other parenteral and sexual risk factors is unclear. In 1997, we performed a case-control study of 2,316 HCV-seropositive blood donors and 2,316 seronegative donors matched on age, sex, race/ethnicity, blood center, and first-time versus repeat-donor status. Odds ratios (OR) and 95% confidence intervals (CIs) were calculated using conditional logistic regression. Questionnaires were returned by 758 (33%) HCV ؉ and 1,039 (45%) control subjects (P ‫؍‬ .001). The final multivariate model included only the following independent HCV risk factors: IDU (OR ‫؍‬ 49.6; 95% CI: 20.3-121.1), blood transfusion in non-IDU (OR ‫؍‬ 10.9; 95% CI: 6.5-18.2), sex with an IDU (OR ‫؍‬ 6.3; 95% CI: 3.3-12.0), having been in jail more than 3 days (OR ‫؍‬ 2.9; 95% CI: 1.3-6.6), religious scarification (OR ‫؍‬ 2.8; 95% CI: 1.2-7.0), having been stuck or cut with a bloody object (OR ‫؍‬ 2.1; 95% CI: 1.1-4.1), pierced ears or body parts (OR ‫؍‬ 2.0; 95% CI: 1.1-3.7), and immunoglobulin injection (OR ‫؍‬ 1.6; 95% CI: 1.0-2.6). Although drug inhalation and a high number of lifetime sex partners were significantly more common among HCV seropositives, they were not associated with HCV after controlling for IDU and other risk factors. IDU, blood transfusion among non-IDU, and sex with an IDU are strong risk factors for HCV among United States blood donors. Weaker associations with incarceration, religious scarification, being stuck or cut with a bloody object, pierced ears or body parts, and immunoglobulin injection must be interpreted with caution. (HEPATOLOGY 2000;31:756-762.)Since the discovery of hepatitis C virus (HCV) was reported in 1989, much has been learned about its epidemiology and pathogenesis. HCV seroprevalence in the general population ranges from 1% to 2% in a number of countries including the United States 1-3 to 12.6% in parts of Italy, 4 and 14.1% in areas of Japan. 5 As a result of selection for those at low risk of infectious disease, HCV prevalence is lower among blood donors, ranging from 0.06% to 1.3% in several countries, and 0.4% in the United States. [6][7][8][9][10] It is hyperendemic among injection drug users (IDUs) in industrialized countries, with infection rates of up to 90%, 11,12 consistent with the high frequency of parenteral blood exposures in this subgroup. Most HCV seropositives have persistent viremia, more than half have chronic hepatitis, and cirrhosis may occur in up to 20%. 13 Other investigators have implied that up to 40% of HCV seropositives do not have recognized parenteral risk factors, 14 leading to speculation that other as-yet-undiscovered modes of transmission may exist. Whether heterosexual transmission occurs at more than a negligible rate is also controversial. [15][16][17][18] Furthermore, a recent study reported that intranasal inhalation of cocaine appeared to be a risk factor for HCV infection in United States blood donors. 19 Clarification of the risk factors for and transmiss...

These findings suggest that offering blood credits and (though to a lesser extent) items of limited value could be safe and effective strategies for retaining donors. Although medical tests were found to have broad appeal, studies are needed to identify tests in which donors would be most interested.

Disease associations of human T lymphotropic virus types I and II (HTLV-I and -II) infection were studied in 154 HTLV-I-infected, 387 HTLV-II-infected, and 799 uninfected blood donors. Adjusted odds ratios (ORs) and 99% confidence intervals (CIs) were derived from logistic regression models controlling for demographics and relevant confounders. All subjects were human immunodeficiency virus type 1-seronegative. HTLV-II was significantly associated with a history of pneumonia (OR, 2.6; 99% CI, 1.2-5.3), minor fungal infection (OR, 2.9; 99% CI, 1.2-7.1), and bladder or kidney infection (OR, 1.6; 99% CI, 1.0-2.5) within the past 5 years and with a lifetime history of tuberculosis (OR, 3.9; 99% CI, 1.3-11.6) and arthritis (OR, 1.8; 99% CI, 1.2-2.9). Lymphadenopathy (> or =1 cm) was associated with both HTLV-I (OR, 6.6; 99% CI, 2.2-19.2) and HTLV-II (OR, 2.8; 99% CI, 1.1-7.1) infection, although no case of adult T cell leukemia/lymphoma was diagnosed. Urinary urgency and gait disturbance were associated with both viruses. This new finding of increased prevalence of a variety of infections in HTLV-II-positive donors suggests immunologic impairment.

Molecular subtyping was used to investigate the epidemiology of human T-lymphotropic virus type II (HTLV-II) in the United States. Nested polymerase chain reaction of the HTLV-II long terminal repeat region followed by restriction fragment length polymorphism (RFLP) analysis was performed on HTLV-II seropositive subjects including 97 U.S. blood donors without major risk factors for HTLV-II infection, 53 injection drug users (IDU), and 10 American Indian blood donors. Three new HTLV-II RFLP types were confirmed with DNA sequencing and phylogenetic analysis. HTLV-II RFLP type aO (Switzer classification) was associated with older age [adjusted odds ratio (OR) 1.06 per year of age, 95% confidence interval (CI) 1.02-1.09] and with Black (OR 5.24, 95% CI 1.90-14.47) and White (OR 4.43, 95% CI 1.67-11.75) race/ethnicity. These data are consistent with an age-cohort effect for HTLV-II RFLP type aO among older White and Black IDU and blood donors. This finding could be explained by an epidemic of non-aO HTLV-II RFLP types among younger persons of Hispanic and other race/ethnicity, superimposed upon endemic HTLV-II RFLP type aO among older Black and White persons.

Summary. Large lymphocytes with basophilic cytoplasm and cleaved/cerebriform nuclei called flower cells have been described in human T-lymphotrophic virus type I (HTLV-I) seropositive individuals and may be precursors of adult T-cell leukaemia (ATL). A cohort of 546 HTLV-seropositive former blood donors, 32 HTLV-positive sexual partners of these donors and 799 HTLV-seronegative controls has been followed as part of the Retrovirus Epidemiology Donor Study. A novel methodology was developed to systematically review peripheral blood slides from these subjects for HTLVrelated lymphocyte abnormalities, using an algorithm based on morphologic features to objectively identify flower cells. The algorithm included: absence of azurophil granules; nuclear chromatin condensation; cell size >1·5 small lymphocytes; nuclear to cytoplasmic ratio >80%; and presence of nuclear folding/lobulation. Peripheral slides from subjects were screened by a medical technologist blinded to HTLV status. 6·8% of HTLV-I subjects (P ¼ 0·0001 versus seronegatives), 0·9% of HTLV-II subjects and 1·1% of seronegatives were confirmed to have cells classified as flower cells by two haematologists using objective criteria, and blinded to serostatus. Despite the higher prevalence of flower cells in HTLV-I positives, no clinical correlations were found. Longitudinal follow-up may yield higher rates of cellular abnormalities as the sequelae of HTLV infection develop.