Vulnerability to APOBEC3G linked to the pathogenicity of deltaretroviruses.

Human retroviruses are derived from simian ones through cross-species transmission. These retroviruses are associated with little pathogenicity in their natural hosts, but in humans, HIV causes AIDS, and human T-cell leukemia virus type 1 (HTLV-1) induces adult T-cell leukemia-lymphoma (ATL). We analyzed the proviral sequences of HTLV-1, HTLV-2, and simian T-cell leukemia virus type 1 (STLV-1) from Japanese macaques (Macaca fuscata) and found that APOBEC3G (A3G) frequently generates G-to-A mutations in the HTLV-1 provirus, whereas such mutations are rare in the HTLV-2 and STLV-1 proviruses. Therefore, we investigated the mechanism of how HTLV-2 is resistant to human A3G (hA3G). HTLV-1, HTLV-2, and STLV-1 encode the so-called antisense proteins, HTLV-1 bZIP factor (HBZ), Antisense protein of HTLV-2 (APH-2), and STLV-1 bZIP factor (SBZ), respectively. APH-2 efficiently inhibits the deaminase activity of both hA3G and simian A3G (sA3G). HBZ and SBZ strongly suppress sA3G activity but only weakly inhibit hA3G, suggesting that HTLV-1 is incompletely adapted to humans. Unexpectedly, hA3G augments the activation of the transforming growth factor (TGF)-ß/Smad pathway by HBZ, and this activation is associated with ATL cell proliferation by up-regulating BATF3/IRF4 and MYC. In contrast, the combination of APH-2 and hA3G, or the combination of SBZ and sA3G, does not enhance the TGF-ß/Smad pathway. Thus, HTLV-1 is vulnerable to hA3G but utilizes it to promote the proliferation of infected cells via the activation of the TGF-ß/Smad pathway. Antisense factors in each virus, differently adapted to control host cellular functions through A3G, seem to dictate the pathogenesis.

The impact of non-disclosure of HIV status and antiretroviral therapy on HIV recency testing and incidence algorithms.

BACKGROUND AND OBJECTIVES: Accurate HIV incidence estimates among blood donors are necessary to assess the effectiveness of programs aimed at limiting transfusion-transmitted HIV. We assessed the impact of undisclosed HIV status and antiretroviral (ARV) use on HIV recency and incidence estimates using increasingly comprehensive recent infection testing algorithms. MATERIALS AND METHODS: Using 2017 donation data from first-time and lapsed donors, we populated four HIV recency algorithms: (1) serology and limiting-antigen avidity testing, (2) with individual donation nucleic amplification testing (ID-NAT) added to Algorithm 1, (3) with viral load added to Algorithm 2 and (4) with ARV testing added to Algorithm 3. Algorithm-specific mean durations of recent infection (MDRI) and false recency rates (FRR) were calculated and used to derive and compare incidence estimates. RESULTS: Compared with Algorithm 4, progressive algorithms misclassified fewer donors as recent: Algorithm 1: 61 (12.1%); Algorithm 2: 14 (2.8%) and Algorithm 3: 3 (0.6%). Algorithm-specific MDRI and FRR values resulted in marginally lower incidence estimates: Algorithm 1: 0.19% per annum (p.a.) (95% confidence interval [CI]: 0.13%-0.26%); Algorithm 2: 0.18% p.a. (95% CI: 0.13%-0.22%); Algorithm 3: 0.17% p.a. (95% CI: 0.13%-0.22%) and Algorithm 4: 0.17% p.a. (95% CI: 0.13%-0.21%). CONCLUSION: We confirmed significant misclassification of recent HIV cases when not including viral load and ARV testing. Context-specific MDRI and FRR resulted in progressively lower incidence estimates but did not fully account for the context-specific variability in incidence modelling. The inclusion of ARV testing, in addition to viral load and ID-NAT testing, did not have a significant impact on incidence estimates.

A case-control study of risk factors for incident hepatitis B virus infection in South African blood donors.

OBJECTIVES: Hepatitis B virus (HBV) infection remains a global health problem. Risk factors for HBV infection are usually assessed in prevalent rather than incident infections. To identify demographic and behavioral risks associated with incident HBV among South African blood donors. METHODS: A case-control study was performed between November 2014 and January 2018. Cases were blood donors testing positive for HBV DNA with or without hepatitis B surface antigen but negative for antibody to hepatitis B core antigen. Participants completed an audio computer-assisted structured interview on exposures during the previous 6 months. Sex-specific multivariable logistic regression yielded independent associations between risks and HBV infection. RESULTS: 56 females and 37 males with incident HBV were compared to 438 female and 439 male controls, respectively. For females, risk factors were accepting money or goods for sex, using agents to prepare one's anus prior to anal sex, penetrating injury, non-Black race, and lower educational status. Men reporting homosexual or bisexual orientation or sex with other men, previous injury, referral for HBV testing, or lack of medical insurance were at increased risk. For both sexes, having more than two male sexual partners increased risk. CONCLUSIONS: Sexual behaviors predominated over parenteral exposures as risks for incident HBV in both female and male blood donors.

HTLV in the Americas: challenges and perspectives

La primera descripción del virus de la leucemia humana de células T tipo 1 (VLHT-1) se hizo en 1980, y al poco tiempo, en 1982, se descubrió el VLHT-2. Desde entonces las características principales de estos virus, a los que a menudo se les llama VLHT-1/2, se han estudiado exhaustivamente. Centroamérica, América del Sur y el Caribe son áreas con una alta prevalencia de VLHT-1 y VLHT-2 donde hay conglomerados de personas infectadas. Las principales vías de transmisión han sido el contacto sexual, la sangre y sus derivados, y la de madre a hijo por la leche materna. El VLHT-1 se asocia con la leucemia o el linfoma de células T maduras (LTM), la mielopatía o paraparesia tropical espástica ligada al VLHT (M/PTE), y la uveítis ligada al VLHT, así como con la dermatitis infecciosa de la infancia. Se necesita más información acerca del posible papel que desempeña el VLHT en la aparición de enfermedades reumáticas, psiquiátricas e infecciosas. En vista de que no se dispone de ninguna cura para la LTM ni la M/PTE, como tampoco de ninguna vacuna para prevenir la transmisión del VLHT-1 y VLHT-2, estas enfermedades acarrean enormes costos sociales y económicos para las personas infectadas, sus parientes y los sistemas de salud. Por este motivo, las intervenciones sanitarias orientadas a asesorar e instruir a personas y poblaciones en alto riesgo revisten una importancia crítica. En el continente americano esto cobra aun más importancia en zonas de alta prevalencia.

HTLV in the Americas: challenges and perspectives

The first description of the human T-lymphotropic virus type 1 (HTLV-1) was made in 1980 followed closely by the discovery of HTLV-2, in 1982. Since then, the main characteristics of these viruses, commonly referred to as HTLV-1/2, have been thoroughly studied. Central and South America and the Caribbean are areas of high prevalence of HTLV-1 and HTLV-2 and have clusters of infected people. The major modes of transmission have been through sexual contact, blood, and mother to child via breast-feeding. HTLV-1 is associated with adult T-cell leukemia/lymphoma (ATL), HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP), and HTLV-associated uveitis as well as infectious dermatitis of children. More clarification is needed in the possible role of HTLV in rheumatological, psychiatric and infectious diseases. Since cures for ATL and HAM/TSP are lacking and no vaccine is available to prevent HTLV-1 and HTLV-2 transmission, these illnesses impose enormous social and financial cost on infected individuals, their families, and health care systems. For this reason, public health interventions aimed at counseling and educating high-risk individuals and populations are of vital importance. In the Americas this is especially important in the areas of high prevalence(AU)

HTLV-I-associated leukemia : a model for chronic retroviral diseases

Human T-lymphotropic virus type I (HTLV-I) has been associated with adult T-cell leukemia/lymphoma (ATL), a malignancy of mature CD4-positive lymphocytes, and tropical spastic paraparesis (TSP), a demyelinating neurological syndrome. This article describes the clinical and pathological features of ATL and reviews the epidemiology of this disease and of its putative etiological agent, HTLV-I. From what is known about the molecular biology and epidemiology of HTLV-I, hypotheses on the etiology of TSP are proposed, and strategies for studying the neurological syndrome are suggested. (AU)

Mother-to-child transmission of human T-cell lymphotropic virus type I (HTLV-1) in Jamaica: association with antibodies to envelope glycoprotein (gp46) epitopes

To study mother-to-child transmission of HTLV-I in Jamaica, we screen antenatal patients in Kingston, Jamaica, from 1983 to 1985. Of 2,329 women, 81 (3.5 percent) were HTLV-I seropositive. Two to three years later, 36 seropositive mothers were recontacted, and blood was drawn from them and their children. All sera were tested for HTLV-I antibodies, and mother's sera were additionally tested for HTLV-I whole-virus antibody titer, syncytium-inhibition neutralizing antibody liter, and titers to six synthetic peptides from the HTLV-I envelope glycoprotein gp46. Seventeen of 74 (23 percent) [95 percent confidence interval (CI) 15-34 percent] children were seropositive. HTLV-I transmission was associated with breast-feeding duration > 6 months [relative risk (RR) 3.2; CI 0.4-22.1], maternal age > 30 years (RR 2.8; CI 1.0 - 7.8), and higher maternal whole-virus antibody titer (RR 3.3; CI 1.3 - 8.5). After controlling for higher whole-virus antibody titer, transmission remained associated with higher titer of neutralizing antibody and higher titer of antibody to the peptide sp4al, corresponding to amino acids 196 - 209 of the gp46 envelope glycoprotein. We conclude that mother-to-child transmission of HTLV-I in Jamaica is associated with longer duration of breast-feeding, older age, and higher HTLV-I antibody titer, in particular to a certain immunogenic portion of the gp46 envelope glycoprotein.(AU)

A case-control study of risk factors for seropositivity to human T-lymphotropic virus type I (HTLV-I) in Jamaica

BACKGROUND: We investigated behavioural and environmental risk factors for seropositivity to human T-lymphotropic virus type I (HTLV-I). METHODS: A nested case-control study of 201 HTLV-I seropositive subjects and 225 age and sex matched seronegative controls was performed using questionaire data from the enrollment visit of a cohort study in 1987-1988. HTLV-I serostatus was confirmed using enzyme-linked imunosorbent assay (ELISA) and Western blot. RESULTS: Among women, the number of lifetime sexual partners (P < 0.05, chi 2 trend) and the number of different men fathering a child by the woman (P < 0.06, chi 2 trend) were associated with HTLV-I seropositivity. Use by the female subject of an intrauterine device (IUD) was associated with an increased risk of seropositivity (odds ratio (OR) = 2.67, 95 percent confidence interval (CI): 1.13-6.23); condom use was rare in this population. Among male subjects, a larger number of lifetime sexual partners was also associated with HTLV-I seropositivity (P < 0.05, chi 2 trend). No association was found between HTLV-I seropositivity and educational attainment, income, or occupation. Having been breastfed as a child or receipt of a blood transfusion had elevated but imprecise OR due to very high and low prevalence of the risk factors, respectively. Several variables relating to insect or animal exposure showed no association with HTLV-I seropositivity. CONCLUSIONS: These data confirm that heterosexual intercourse is a major route of HTLV-I transmission, but do not support suggestions of insect or environmental vectors.(AU)

A prospective study of transmission by transfusion of HTLV-I and risk factors associated with seroconversion

To evaluate the risk of transfusion-related transmisssion of HTLV-I in Jamaica, a prospective study was initiated, prior to availability of a licensed HTLV-I serological screening assay. This information would prove useful in formulating strategies for blood-donor screening. We followed 118 pre-transfusion HTLV-I-negative transfusion recipients at monthly intervals post-transfusion for 1 year. Laboratory and questionnaire data were obtained at each visit to evaluate the clinical and immunological status of recipients. Cumulative incidence of HTLV-I seroconversion was estimated and risk-factor data associated with seroconversion among 66 HTLV-I-exposed transfusion recipients were analyzed. Seroconversion occurred in 24/54 (44 percent) of recipients of HTLV-I-positive cellular blood components, 0/12 recipients of positive non-cellular donor units and 0/52 recipients of HTLV-I-negative donor units. Significant risk factors associated with recipient seroconversion were receipt of a seropositive cellular blood component stored for less than one week odds ratio (OR) = 6.34, 95 percent confidence interval (CI) = 1.83 to 21.92], male sex (OR = 4.79, 95 percent CI = 1.15 to 20.0) or use of immunosuppressive therapy at time of transfusion (OR = 12.20, 95 percent CI = 0.95 to 156). Risk of blood-borne infection per person per year in Jamaica was estimated to be 0.009 percent. Our results confirm that blood transfusion carries a significant risk of HTLV-I transmission and that screening of donor blood effectively prevents HTLV-I seroconversion. Recipients at greatest risk for seroconversion were those who required multiple transfusions or who were receiving immunosuppressive therapy at the time of transfusion. These patients should be given priority in receiving selectively screened blood components, if universal blood-donor screening for HTLV-I is not possible (AU)

Clinical outcome following transfusion acquired HTLV-1 infection in Jamaica - abstract

To evaluate the acute and long-term risk of adverse clinical outcomes following transfusion acquired HTLV-1 infection, a prospective cohort of recipients were followed-up after transfusion between 1987 and 1988. Pre-transfusion seronegative recipients of HTLV-1 positive blood components were retrospectively identified and subsequently enrolled in the Jamaica Transfusion Study. Recipients were followed at monthly intervals post-tranfusion for one year, then semi-annually. Laboratory questionnaire data and a brief physical examination were obtained at each visit to evaluate the clinical, haematological and immunological status of recipients. Further diagnostic evaluation by dermatology, neurology, haematology and rheumatology were performed when clinically indicated. Sixty-six (66) recipients received Western Blot and/or RIPA confirmed HTLV-1 positive blood components; 24/66 recipients of confirmed positive components sero-converted. Five subjects, 4 sero-converters (SC) and one non-seroconverter (NSC), developed skin rashes 18-39 months post-transfusion [odds ratio (OR) = 8.2, Fishers exact test p = 0.06. One SC developed cleaved atypical lymphocytes on peripheral blood smear 32 months post-transfusion (PT). One SC developed TSP 36 months PT. Two NSC with transient antibody to HTLV-1 PT developed rheumatoid factor negative polyarthritis 20 and 25 months PT. Recipients of HTLV-1 sero-positive blood components appear to be at risk for adverse clinical events. As has been previously reported, TSP can develop after a short incubation period following transfusion findings reinforce the potential public health benefit of HTLV-1 testing of donor blood. However, in countries where health resources are limited, the feasibility of such screening is limited by financial constraints (AU)

Coincidental HTLV-I infection influences outcome of treatment of strongyloidiasis - abstract

It is uncertain whether HTLV-I infection and Strongyloidiasis are related other than by chance. A consecutive series of Jamaican patients and controls have been analysed retrospectively for anti-Strongyloides and HTLV-1 antibodies to determine whether either influences the outcome of anti-helminthic therapy. Twenty-seven Jamaicans (16 M, 11F) mean age 50.2 years (range 16-85), who were found to have Strongyloides stercoralis infection were studied at the University Hospital of the West Indies. At the same time, a parasite-negative group of 13 patients (6M, 7F) of mean age 37.6 years, (range 23-53), with minor or no gastrointestinal disease served as controls. Pretreatment blood samples were taken from the Strongyloides group and controls. Serum was subsequently tested for IgG antibodies to filariform Strongyloides stercoralis larval antigens by ELISA and to HTLV-1 by ELISA and Western Blot. Outcome of the treatment of Strongyloidiasis with thiabendazole (25 -mg/kg b.d. orally for 10 days was determined at 2 months. Strongyloides reciprocal antibody titre was considerably higher in patients than controls, mean 870 vs 167; median 1,024 vs 8 (p<0.001). The sensitivity of the antibody test was 93 percent, but the specificity was 69 percent at best. There was no correlation with the anti-Strongyloides antibody titre and outcome with anti-helminthic therapy. HTLV-1 antibodies were found only in the Strongyloides patients, 12 of 27 (44 percent); antibody titres were high and positive with both test used: only one patient was known beforehand to have a disease associated with HTLV-1 infection. Of those 12 with HTLV-1 antibodies, 3 (25 percent) were cured, 7 still had the infection at 2 months, a further 2 had died or defaulted from follow-up. Of the 15 patients without HTLV-1 antibodies, 9 (60 percent) were cured, 3 still had the infection and 3 had died or defaulted. By chi-square analysis, the difference is significant whether one includes all the deaths and defaulters on an intention-to-treat basis or just those who were available at 2 months post-therapy. However, since none of the deaths were related to Stongyloidiasis or HTLV-1 injection, it is probably justifiable to exclude the deaths from the computation. These results show that the association of Strongyloidiasis and HTLV-1 is more than chance clustering. Not only is the prevalence of HTLV-1 antibodies far higher in the patients with Strongyloidiasis than in the normal Jamaican population, but that concurrent asymptomatic HTLV-1 infection interferes with anti-helminthic treatment (AU)

Maternal infant transmission of HTLV-I in Jamaica - abstract

HTLV-I has been aetiologically linked with adult T-cell leukaemia and tropical spastic paraparesis. Studies from Japan have shown that transmission from mother to child is the principal mode of early-life infection; breast milk has been implicated as the route of this transmission. To study the frequency of, and risk factors for, maternal-infant transmission in Jamaica, we screened women attending a Kingston antenatal clinic for the presence of HTLV-I antibodies. Of 2,329 women screened, 81 (3.5 percent) were seropositive. Two to three years following screening, 35 seropositive mothers were successfully recontacted, a questionnaire was administered, and blood was collected from the mothers and the child of the original pregnancy (index child) as well as any other children. Five of 34 (15 percent) index children and 8 of 31 (26 percent) siblings were seropositive. Having a seropositive child was significantly associated with older maternal age (p<0.05) and a higher level of maternal antibody titre (p<0.05). Seropositive index children tended to breast feed for longer than seronegative index children (11 months vs 1 month; p=0.18). We conclude that HTLV-I transmission occurs in Jamaica at rates similar to those seen in Japan. Older age and measures of higher "viral load" such as elevated antibody titre are associated with transmission. Although the evidence is suggestive that transmission occurs through breast-milk, a larger study is currently underway to this tissue (AU)

HIV and HTLV-I infection among homosexual men in Kingston, Jamaica - abstract

From August 1985 through January 1986, 123 homosexual or bisexual men from the Kingston area were enrolled in a study to determine the prevalence of human immunodeficiency virus (HIV) and the human T-lymphotrophic virus type I (HLTV-I) and the levels of risk factors for these infections. Eighteen men (15 percent) were sero-positive for HIV and 11 (9 percent) were sero-positive for HTLV-I. Only one man was positive for both viruses. The median age was 27 years (range 17 to 70). Overall, the level of promiscuity was lower than that reported in studies of homosexual men in the U.S.A. and in Europe. However, almost a third of the men reported having had homosexual encounters with foreign visitors or whilst travelling outside Jamaica. The presence of lymphadenopathy (p<0.05) was higher in HIV sero-positive patients, as was the percentage who reported having sex with men from the U.S.A. (p=0.16). Men who were sero-positive for HTLV-I tended to be more promiscuous than their sero-negative counterparts; the proportion with a history of gonorrhoea and the mean number of homosexual acts per week were both increased (p<0.05). A history of receptive anal intercourse and the mean number of homosexual partners per month were increased in positive subjects but the difference did not reach statistical significance. These results suggest that HTLV-I is an endemic, sexually transmitted infection. In contrast, HIV appears to have entered this population through homosexual contact with foreigners; the lack of association between HIV infection and promiscuity may be due to the small number of positives and the sporadic nature of transmission early in an epidemic (AU)

Human T-lymphotropic virus type I (HTLV-I) seroprevalence in Jamaica - II geographic and ecological 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 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 (ó1,000 ft (305 m)) were more likely to be HTLV-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 in significance 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, breast-feeding habits, or sexual behaviour, which are known determinants of HTLV-I zero prevalence. (AU)

Modelling the risk of adult T-Cell leukemia/lymphoma in persons infected with human T-lymphotropic virus type I

Adult T-cell leukemia/lymphoma (ATL), a malignancy of mature CD4-positive lymphocytes, has been etiologically linked to the human retrovirus HTLV-I. Although a long latent period is suggested from malignant studies, little prospective information on the risk of developing ATL among persons with HTLV-I infection is available. We present here a model of ATL risk based upon age- and sex-specific HTLV-I seroprevalence data from a cross-sectional survey of 13,000 Jamaicans and ATL incidence data from a 2« year case-control study. By examining the age-specific incidence of ATL relative to both adult and childhood-acquired seropositivity versus childhood-acquired seropositivity alone, we provide evidence in support of the hypothesis that childhood infection with HTLV-I is important to the development of ATL. Using this model, the cumulative lifetime risk of ATL for those infected before age 20 is estimated to be 4.0 percent for males and 4.2 percent for females. Under this hypothesis, HTLV-I-associated diseases with shorter latent periods, such as tropical spastic paraparesis, should have a higher incidence in adult females than in adult males. (AU)

Gastrointestinal parasitic infection in healthy Jamaican carriers of HTLV-I

A subsample (1.6 percent; n = 13,260) of a healthy Jamaican population of food-handlers, studied by Murphy et al. (1991), who were serologically positive (n = 99) or negative (n = 113) for HTLV-I was investigated for intestinal parasitic infection using coprological methods. Helminth infection included Ascaris lumbricoides (2.8 percent), Trichuris trichiura (7.1 percent) and hookworms (6.1 percent). Entamoeba coli was found in 21.8 percent of samples, while E. hartmanni, Giardia lamblia, Endolimax nana, Iodamoeba butschlii and Chilomastrix mesnili each occurred in less than 10 percent of responders. T. trichiura displayed a higher prevalence (10.6 vs 3 percent (chi 2 = 4.623;p = 0.03) in the HTLV-I negative group. G. lamblia was detected more frequently among HTLV-I carriers compared to controls (9.1 and 3.5 percent respectively), but the association was not statistically significant (chi 2 = 2.825;p = 0.09). Infection with intestinal parasites is likely to occur independent of HTLV-I status: however, possible HTLV-I-induced immunosuppression may lead to higher intensity infections of certain organisms thus facilitating easier detection using parasitological methods. The immunomodulatory potential of HTLV-I infection in the aetiology of non-malignant diseases requires further investigation. (AU)

Health effects of human T-lymphotropic virus type I (HTLV-I) in a Jamaican cohort

BACKGROUND: Other than adult T-cell leukaemia (ATL) and HTLV-I associated myelopathy (HAM), the health effects of infection with human T-lymphotropic virus type I (HTLV-I) are not well defined. METHOD: A cohort of 201 confirmed HTLV-I seropositive Jamaican food service workers and 225 seronegative controls of similar age and sex from the same population was examined. A health questionnaire, physical examination, and laboratory tests were performed at enrollment into the cohort in 1987-1988. RESULTS: One of 201 HTLV-I seropositives, but no controls were diagnosed with HAM, for a prevalence of 0.5 percent (95 percent confidence interval) (CI) 0.01-2.7 percent); no cases of ATL were diagnosed. While there was no difference in current symptoms, the HTLV-I seropositive group was more likely to report a past medical history of hepatitis or jaundice (OR = 3.49, 95 percent CI: 0.93-13.08), malaria (OR = 2.13, 95 percent CI: 0.96-4.73), and dengue fever (OR = 1.37, 95 percent CI 0.82-2.29); however, these differences were of borderline statistical significance. Low income HTLV-I seropositive women had lower body weight (P , 0.01) and body mass index (P < 0.009) than their seronegative counterparts; similar differences were seen in the smaller male group. A trend toward higher prevalence of severe anaemia (haemoglobin < 10 g/dl) (12.6 percent verus 7.7 percent, P < 0.105) and a significantly lower prevalence of eosinophilia (1.0 percent verus 6.3 percent, P < 0.004) was seen among HTLV-I seropositives are asymptomatic, HAM may be diagnosed in approximately 0.5 percent of carriers. Chronic HTLV-I infection may also subtle effects on body mass and haematological parameters.(AU)

Risk factors and cofactors for human T-cell lymphotropic virus type 1 (HTLV-1) - associated myelopathy/tropical spastic paraparesis (HAM/TSP) in Jamaica

Human T-cell lymphotrophic virus type 1 (HTLV-1) has been etiologically associated with a neurologic syndrome called HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) as well as with adult T-cell leukemia/lymphoma. The authors sought to quantify the risk in Jamaica of HAM/TSP associated with HTLV-1 infection and cofactors associated with this disease among infected individuals. Between 1988 and 1989, prevalent and incident HAM/TSP patients and controls with other neurologic diseases were enrolled in a retrospective study. A second control group was composed of HTLV-1-seropositive, asymptomatic carriers in Jamaica, ascertained in a separate study conducted in 1988. Although HTLV-1 seropositivity was not a component of the case definition for HAM/TSP, all 43 HAM/TSP patients were HTLV-1 seropsitive compared with two (4.0 percent) of the controls with other neurologic diseases. Given HTLV-1 seropositivity, one cofactor associated with the risk of HAM/TSP was young age at initial heterosexual intercourse (odds ratio = 4.00, 95 percent confidence interval 1.29-12.46 for individuals aged ó15; odds ratio = 4.26, 95 percent confidence interval 1.41-12.90 for individuals aged 16-17 years at initial intercourse). Among individuals who reported this early age at initial sexual intercourse, an increased risk of HAM/TSP was associated with having reported more than five lifetime sexual partners (odds ratio = 2.88, 95 percent confidence interval 0.90-8.70). Neither an early age at initial sexual intercourse nor the number of lifetime sexual partners was a risk factor for adult T-cell leukemia/lymphoma. These data support the hypothesis that HAM/TSP is associated with sexually acquired HTLV-1 infection, whereas adult T-cell leukemia/lymphoma is not. (AU)