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Biomedical subjects

E L Murphy

Publications and source records attributed to E L Murphy.

At least 55 records · Page 3Linked to original sources
PubMed1996

The clinical epidemiology of human T-lymphotropic virus type II (HTLV-II).

Human T-lymphotropic virus type II (HTLV-II) is endemic among Amerindian tribes and is also prevalent at high levels among certain U.S. and European intravenous drug users (IVDU), and at lower levels among blood donors. Most epidemiologic evidence supports transmission via parenteral, breast-feeding, and sexual routes, although more quantitative studies of the latter two routes are needed. There is growing evidence that HTLV-II causes a neurologic syndrome similar to HTLV-I-associated myelopathy, but there is some controversy as to whether the clinical features of this illness differ between HTLV-II and HTLV-I cases. Preliminary evidence also suggests that HTLV-II may predispose to skin and soft tissue bacterial infections among IVDU. Questions amenable to future research are discussed.

Bacterial Infections↗
PubMed1996

Human T-lymphotropic virus type II seroprevalence among emergency department and clinic patients.

To determine the seroprevalence of human T-lymphotropic virus types I and II (HTLV-I and HTLV-II) among emergency department and clinic patients at a San Francisco, California, hospital, consecutive patients from 4 outpatient settings-emergency department, medical clinic, antenatal clinic, and neighborhood health centers-were tested for antibody to 1 of the viruses using an enzyme-linked immunosorbent assay and Western blot test. Of 4,019 patients, 169 (4.2%) had antibody to HTLV-I or -II; the seroprevalence of HTLV-II (3.5%) was greater than that of HTLV-I (0.7%). Seroprevalence for HTLV-II was highest in the emergency department (6.9%) and neighborhood clinics (3.9%) and in those aged 30 to 59 years (5.9%). Crude HTLV-II prevalence was higher in men (5.2%) than in women (2.2%), but sex was not an independent risk factor after age and location were controlled for. This study showed a higher seroprevalence of HTLV-I and HTLV-II among outpatients than did previous studies, probably because of a high proportion of injection-drug users. In view of the recent description of HTLV-II-associated myelopathy, studies of neurologic disease in this population may be warranted. HTLV-II should be included in the list of occupationally transmitted infections for hospitals with many injection-drug-using patients.

Adult↗
PubMed1995

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

Human T-cell lymphotropic virus type I (HTLV-I) has been etiologically associated with a neurologic syndrome called HTLV-I-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-I 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-I-seropositive, asymptomatic carriers in Jamaica, ascertained in a separate study conducted in 1988. Although HTLV-I seropositivity was not a component of the case definition for HAM/TSP, all 43 HAM/TSP patients were HTLV-I seropositive compared with two (4.0%) of the controls with other neurologic diseases. Given HTLV-I seropositivity, one cofactor associated with the risk of HAM/TSP was young age at initial heterosexual confidence interval 1.29-12.46 for individuals aged < or = 15; odds ratio = 4.26, 95% 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% confidence interval 0.90-8.70). Neither an early age at initial sexual intercourse or 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-I infection, whereas adult T-cell leukemia/lymphoma is not.

Adolescent↗
PubMed1994

Transfusion-related transmissible diseases: detection by polymerase chain reaction-amplified genes of the microbial agents.

The detection of blood-borne microbes by PCR has broadly and rapidly progressed in the past 5 years as briefly described in this article. This progress has been largely because of the scientific developments made at Roche Molecular Systems by Sninsky et al through collaborations with academic and Government institutions. This unprecedented cooperation propels the continuing work at Roche Molecular Systems to bring the PCR technology into routine laboratory diagnosis. Whether the success of EIA in virtual elimination of hepatitis and retroviral infections can be matched by the cost-effectiveness of putative application of PCR in screening blood supply remains to be determined.

Bacterial Infections↗
PubMed1994

Seroprevalence of human T-lymphotropic virus, hepatitis C virus, and human immunodeficiency virus in Asian American potential bone marrow donors.

BACKGROUND: Asian Americans are generally underrepresented both as volunteer blood and bone marrow donors. STUDY DESIGN AND METHODS: To investigate the risk of transfusion transmission of viruses that is associated with increasing participation by Asian American donors, antibodies to human T-lymphotropic virus (HTLV), hepatitis C, and human immunodeficiency virus in Asian American volunteers recruited as potential bone marrow donors were measured. A total of 1354 Asian Americans were enrolled in the study, of whom 54 percent were Chinese, 26 percent Japanese, 9 percent Filipino, 4 percent Korean, 3 percent Indian, and 5 percent of other Asian or mixed Asian and other ethnicity. The majority of the study population was aged 20 through 49 and of high socioeconomic status, as indicated by education and income. Viral antibodies were measured with both screening enzyme-linked immunosorbent assays and supplemental testing, and polymerase chain reaction was used to resolve discrepant HTLV results. RESULTS: Confirmed seroprevalence rates for HTLV were 0.15 percent with one manufacturer's Western blot and 0.3 percent with the other; however, no sample was positive for HTLV types I or II in polymerase chain reaction. Confirmed seroprevalence to hepatitis C virus was 0.5 percent. No subject was seropositive for human immunodeficiency virus. CONCLUSION: On the basis of the moderate size and high education level of this study population, it is concluded that Asian American volunteer bone marrow donors do not pose a greater risk for transmission of HTLV type I or II, human immunodeficiency virus, or hepatitis C virus than does the average American blood donor.

Adolescent↗
PubMed1993

Determination of human T lymphotropic virus type by polymerase chain reaction and correlation with risk factors in northern California blood donors.

To determine the relative prevalence of human T lymphotropic virus (HTLV) types I and II, type-specific polymerase chain reaction (PCR) was done on seropositive northern California blood donors. From October 1988 through March 1990, 67 (0.055%) of 122,517 blood donors had confirmed HTLV antibody. Seropositive donors were more likely to be middle-aged, female, and nonwhite than the overall donor base. PCR of samples from 30 HTLV-seropositive donors yielded 19 (63%) with HTLV-II and 9 (30%) with HTLV-I; 2 (7%) were repeatedly negative by PCR. HTLV-I-infected subjects had ancestry (n = 3), sexual contact (n = 3), or paternal military service in (n = 1) Japan or the Caribbean. HTLV-II carriers reported past intravenous drug abuse (n = 3) or sex with a drug user (n = 11). Two carriers of each type reported previous blood transfusions, and 1 HTLV-II carrier was a dentist with no other risk factors for retroviral infection.

Adult↗
PubMed1993

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

To study mother-to-child transmission of HTLV-I in Jamaica, we screened antenatal patients in Kingston, Jamaica, from 1983 to 1985. Of 2,329 women, 81 (3.5%) 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 titer, and titers to six synthetic peptides from the HTLV-I envelope glycoprotein gp46. Seventeen of 74 (23%) [95% confidence interval (CI) 15-34%] 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 sp4a1, 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.

Adolescent↗
PubMed1993

Human T-lymphotropic virus type I seroprevalence among Japanese Americans.

The epidemiology of human T-lymphotropic virus type I (HTLV-I) infection is not well defined in Japanese Americans. This impairs using approaches that could reduce viral transmission and monitor carriers for the disease. Using enzyme-linked immunosorbent assay and p21e recombinant Western blot testing, HTLV-I antibody was measured in unlinked samples from Japanese-American patients at 4 physicians' offices in San Francisco, California. Of 442 patients, 4 (0.9%; 95% confidence interval 0.25%, 2.3%) were confirmed seropositive, all with an HTLV-I rather than an HTLV-II pattern on Western blot. Seroprevalence was highest among the issei or immigrant generation (3/230 or 1.3%) compared with the second-generation nisei (1/191 or 0.5%) or third-generation sansei (0 of 17). Prevalence did not differ by age or sex, although the number of positive subjects in each subgroup was small. Of 88 patients with familial origins in endemic areas of southern Japan, none were seropositive. In this sample of Japanese Americans, HTLV-I seroprevalence was lower than in residents of endemic southern Japan but higher than among American blood donors. The prevalence was most similar to that in nonendemic areas of Japan. The public health implications of HTLV-I infection among Japanese Americans are discussed.

Adult↗
PubMed1992

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

To evaluate the risk of transfusion-related transmission 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%) 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% confidence interval (CI) = 1.83 to 21.92], male sex (OR = 4.79, 95% CI = 1.15 to 20.0) or use of immuno-suppressive therapy at time of transfusion (OR = 12.20, 95% CI = 0.95 to 156). Risk of blood-borne infection per person per year in Jamaica was estimated to be 0.009%. 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.

Blood Donors↗
PubMed1992

Cost-benefit analysis of autologous blood donation in obstetrics.

OBJECTIVE: To determine whether there are predictors of peripartum transfusion, other than placenta previa, that identify a population of pregnant women whose risk of transfusion is high enough to justify antepartum autologous blood donation. METHODS: Using an established perinatal data base, we studied 14,267 consecutive term deliveries without placenta previa. Univariate and multivariate analyses were performed to assess ten predictors of peripartum transfusion that might reasonably be detected in the antepartum period. Costs were calculated for a hypothetical autologous blood donation program to prevent transfusion-related infection. RESULTS: Red-cell transfusion was used in 150 deliveries (1.1%). A total of 424 units was transfused (2.9 per 100 deliveries). Four risk factors were significantly (P less than .05) predictive of peripartum red-cell transfusion: preeclampsia (adjusted odds ratio 3.69), multiple gestation (2.82), elective cesarean (1.71), and nulliparity (1.51). Controlling for these, there was no association between transfusion and previous postpartum hemorrhage, previous cesarean with trial of labor, prior abortions, induction of labor, or ethnic group. A hypothetical antepartum blood donation program restricted to patients with three or more risk factors would cost $32,800-130,700 per case to prevent transfusion-related hepatitis and $26,000,000-78,000,000 per case to prevent human immunodeficiency virus infection. CONCLUSION: In obstetric patients without placenta previa, the need for peripartum red-cell transfusion cannot be predicted with sufficient accuracy to justify the costs of antepartum autologous blood donation.

Blood Transfusion, Autologous↗
PubMed1991

Evaluation of screened blood donations for human immunodeficiency virus type 1 infection by culture and DNA amplification of pooled cells.

BACKGROUND: Reports of transmission of the human immunodeficiency virus type 1 (HIV-1) from transfusions of screened blood and reports of silent, antibody-negative HIV-1 infections in persons at high risk continue to foster concern about the safety of the blood supply. Previous estimates of the risk of HIV-1 range from 1 in 38,000 to 1 in 300,000 per unit of blood but are based on either epidemiologic models or the demonstration of seroconversion in recipients. METHODS: We isolated peripheral-blood mononuclear cells from blood that was fully screened and found to be seronegative, combined them into pools of cells from 50 donors, and tested them for HIV-1 by viral culture and the polymerase chain reaction, using protocols specifically adapted for this analysis. RESULTS: The 1530 pools of mononuclear cells were prepared from 76,500 blood donations made in San Francisco between November 1987 and December 1989. Of these pools, 1436 (representing 71,800 donations) were cultured successfully; 873 (43,650 donations) were evaluated by the polymerase chain reaction. Only one pool was confirmed as HIV-1--infected by both methods. After adjustment for sample-based estimates of the sensitivity of the detection systems using culture and the polymerase chain reaction, the probability that a screened donor will be positive for HIV-1 was estimated as 1 in 61,171 (95 percent upper confidence bound, 1 in 10,695). CONCLUSIONS: Silent HIV-1 infections are exceedingly rare among screened blood donors, so the current risk of HIV-1 transmission from blood transfusions, even in high-prevalence metropolitan areas, is extremely low.

Acquired Immunodeficiency Syndrome↗
PubMed1991

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.

Adolescent↗
PubMed1991

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.

Adolescent↗
PubMed1991

Detection of early human T-cell lymphotropic virus type I antibody patterns during seroconversion among transfusion recipients.

From a cohort of human T-cell lymphotropic virus type I (HTLV-I) exposed transfusion recipients (N = 71) enrolled in the Jamaican Transfusion Study, 11 were selected for detailed laboratory evaluation. All recipients were followed at monthly intervals for 6 months and then bimonthly up to 1 year for evidence of HTLV-I seroconversion. Without regard to results on screening assays, pretransfusion and posttransfusion samples were tested with two licensed HTLV-1 whole-virus screening enzyme immunoassays (EIAs), recombinant EIAs for antibody against tax (p40x) and p21e envelope, standard whole virus Western blot (WB), WB enhanced with recombinant p21e, and radioimmunoprecipitation assay (RIPA). In the early period posttransfusion, antibody to gag core protein was predominant with anti-p24 generally appearing before anti-p19. Recombinant anti-p21e envelope protein, in EIA and WB format, was frequently the earliest envelope reactivity detected, while anti-gp46 in WB and anti-gp61/68 in RIPA system appeared later. Anti-tax antibodies appeared later in the time course of seroconversion. The whole-virus EIAs were less sensitive than the confirmatory assays. The combination of WB and RIPA or WB enhanced with recombinant p21e appeared equally effective in confirming samples as positive by the Public Health Service two gene group confirmatory algorithm. However, specificity of this assay approach could not be addressed in this study.

Adolescent↗