Human T-lymphotropic virus type I (HTLV-I) seroprevalence in Jamaica. I. Demographic determinants.

During 1985 and 1986, the authors measured antibodies to human T-lymphotropic virus type I (HTLV-I) in a cohort of 13,260 Jamaicans from all parts of the island who applied for food-handling licenses. HTLV-I seroprevalence was strongly age and sex dependent, rising from 1.7% (10-19 years) to 9.1% (greater than or equal to 70 years) in men and from 1.9% (10-19 years) to 17.4% (greater than or equal to 70 years) in women. In a logistic regression analysis, women were more likely to be seropositive than were men, and farmers, laborers, and the unemployed were more likely to be HTLV-I seropositive than were those reporting student or professional occupations. In men, African ethnicity was associated with HTLV-I seropositivity in the univariate analysis but was not a risk factor after adjustment for age and sex. There was a trend toward higher age-stratified HTLV-I seroprevalence among younger women who reported more pregnancies, but older multigravidas had lower rates of HTLV-I seropositivity. Persons born outside Jamaica had significantly lower seroprevalence than did those born in Jamaica, but they were of slightly different ethnic and occupational compositions than those born in Jamaica.

Human T-lymphotropic virus type I (HTLV-I) seroprevalence in Jamaica. II. Geographic and ecologic determinants.

An island-wide cohort of 13,260 Jamaicans who applied for food-handling licenses during 1985 and 1986 were tested for antibodies to human T-cell lymphotropic virus type I (HTLV-I). Demographic and residence history data were linked to geographic and ecologic measures of elevation, rainfall, crop-growing areas, population density, and additional measures of urbanization and correlated with HTLV-I antibody status. By logistic regression analysis (performed separately for men and women), men and women who currently resided at low elevation (less than or equal to 1,000 ft (305 m)) were more likely to be HTLV-I infected than were those residing at high elevation. Men, but not women, who were born in citrus-growing areas were more likely to be HTLV-I infected than were men who were born in other areas. By univariate analysis, there was a significant positive trend of increasing HTLV-I seroprevalence with increasing amount of annual rainfall associated with birthplace and primary residence areas. However, these associations did not remain significant after adjusting for age and sex. These environmental associations raise the possibility of new modes of viral transmission or host response to infection, although they may simply be surrogates for socioeconomic status, breastfeeding habits, or sexual behavior, which are known determinants of HTLV-I zero prevalence.

Sexual transmission of human T-lymphotropic virus type I (HTLV-I).

STUDY OBJECTIVE: To study the seroprevalence of human T-lymphotropic virus type I (HTLV-I) in a sexually active population and to determine sexual behavior risk factors for infection. DESIGN: Cross-sectional seroprevalence study using enzyme-linked immunosorbent assay (ELISA) and Western blot. Risk-factor data were gathered by administered questionnaire and chart review. SETTING: Two urban, primary care clinics for persons with sexually transmitted diseases run by the Jamaican Ministry of Health. PATIENTS: Of the 2050 consecutive patients presenting with new episodes of sexually transmitted disease, 1977 patients were eligible for analysis. MEASUREMENTS AND RESULTS: Overall HTLV-I seroprevalence was 5.7%; prevalence increased with age from 1.6% (age, 14 to 19 years) to 5.1% (age, 30 years and older) in men and from 5.3% (age, 14 to 19 years) to 14.1% (age, 30 years and older) in women. Compared with a reference cohort of food service employees, age-adjusted HTLV-I seroprevalence was increased in female patients with sexually transmitted disease (odds ratio = 1.83; CI, 1.41 to 2.83) but not in male patients with sexually transmitted disease. Independent risk factors for HTLV-I infection in women included having had more than ten lifetime sexual partners (odds ratio = 3.52, CI, 1.28 to 9.69) and a current diagnosis of syphilis (odds ratio = 2.12; CI, 1.12 to 3.99). In men, a history of penile sores or ulcers (odds ratio = 2.13; CI, 1.05 to 4.33) and a current diagnosis of syphilis (odds ratio = 3.56; CI, 1.24 to 10.22) were independent risk factors for HTLV-I infection. Of 1977 patients, 5 (0.3%) had antibodies to human immunodeficiency virus type 1 (HIV-1), including 2 with HTLV-I and HIV-1 coinfection. CONCLUSIONS: We conclude that HTLV-I is transmitted from infected men to women during sexual intercourse. Our data are consistent with the lower efficiency of female-to-male sexual transmission of HTLV-I, but penile ulcers or concurrent syphilis may increase a man's risk of infection.