Human Herpesvirus 8 Transmission Research Articles

Transmission of human herpesvirus 8 by sexual activity among adults in Lagos, Nigeria.

Human herpesvirus 8 (HHV-8) infection is common in Africa, but prevalence varies geographically. Studies in Europe and America suggest spread through homosexual contact, but evidence of heterosexual spread is inconsistent. We examined the association between HHV-8 and markers of risky sexual activity in Nigeria. The study subjects included an adult referent population at relatively low risk of HIV infection, patients attending a sexually transmitted disease (STD) clinic, and female commercial sex workers (CSW). Sera were collected between 1991 and 1994 to study the epidemiology of retroviruses and STD in Lagos, Nigeria. Residual samples were tested for HHV-8 antibodies using a K8.1 enzyme immunoassay and for antibodies to syphilis, chancroid, herpes simplex virus 2, HIV-1/2, and HTLV-1. Associations were sought using chi square tests and logistic regression. Overall, HHV-8 prevalence was 26.5% in 2002 study subjects, being higher among CSW and STD patients (31% in each) than in the referent population (19%). HHV-8 prevalence in women was approximately half that in men in both the referent and the STD populations. Increasing age and STD were each associated with HHV-8-seropositivity in men and women, and among women being a CSW was also a risk factor. HHV-8 antibodies were more frequently detected in those with laboratory evidence of STD in each group. Having at least one STD was associated with having HHV-8 antibodies. The higher prevalence of HHV-8 antibody in groups with multiple sexual partners and the association with STD among individuals both support the sexual transmission of HHV-8 in African adults.

Prevalence of human herpesvirus 8 antibodies in the population of Belém, Pará, Brazil.

Serum samples from 497 children and adults inhabiting two neighbourhoods (Guamá and Terra Firme) in Belém, Pará, North Brazil were screened for the presence of human herpesvirus 8 (HHV-8) antibody using an enzyme-linked immunosorbent assay. An overall 16.3% prevalence was found for these urban communities. Taken both genders together, prevalence rates of HHV-8 antibody increase gradually, across age-groups, ranging from 12.0% to 33.3%. When seroprevalence is analysed by gender, similar rates are found for female (18.4%) and male (14.0%) individuals. In the former gender group, seroprevalence rates increased from 10.3%, in children < or = 10 years of age, to 30.0% in adults 41-50 years of age. Conversely, among male subjects, the prevalence of HHV-8 antibodies decreased from 13.3% in children/young adults aged < or = 10 to 20 years of age to 6.1% in adults aged 21-30 years. From the 31-40 year-old group male onwards, seropositivity rates increased gradually, ranging from 8.3% to 66.7%. A significant difference in seropositivity rates was noted when comparing 21-30 age groups for female and male subjects: 23.3% and 6.1%, respectively (P = 0.03). Geometric mean optical densities were found to increase slightly from the lower to the higher age-groups. Our data suggest that transmission of HHV-8 occurs frequently in the general urban population of Belém, and that prevalence of antibody seems to increase with age.

Correlates of human herpesvirus 8 seropositivity among heterosexual men in Kenya.

Several studies have suggested that sexual transmission of human herpesvirus 8 (HHV-8) occurs among homosexual men in developed countries. However, few studies have examined heterosexual HHV-8 transmission, especially among African populations in which HHV-8 is endemic. To determine the seroprevalence and correlates of HHV-8 infection among heterosexual African men. Cross-sectional study. Participants were 1061 men enrolled in a prospective cohort study of risk factors for HIV-1 acquisition among trucking company employees in Mombasa, Kenya. Stored frozen sera from the study baseline visit were tested for antibodies to HHV-8 by whole-virus lysate ELISA. HHV-8 seroprevalence was 43%. In multivariate logistic regression analysis, HHV-8 infection was independently associated with older age [for men aged 30-39 years: odds ratio (OR), 1.5; 95% confidence interval (CI), 1.1-2.0; for men aged > or = 40 years: OR, 1.7; 95% CI, 1.1-2.7, compared with men aged < 30 years], Christian religion (OR, 1.6; 95% CI, 1.2-2.1), being uncircumcised (OR, 1.5; 95% CI, 1.0-2.2), and ever having syphilis (OR, 2.2; 95% CI, 1.4-3.5). Ever having used condoms was associated with decreased likelihood of infection (OR, 0.7; 95% CI, 0.6-1.0). Seropositivity was not significantly related to other sexual behaviors characterized or to HIV-1 status. HHV-8 seropositivity is common in this population and increases with age, suggesting on-going transmission during adulthood. Infection was more common among men who were uncircumcised or who had ever had syphilis and was less common among those who had ever used condoms, suggesting that sexual factors may play a role in HHV-8 transmission. Prospective studies of HHV-8 acquisition in heterosexual African populations are needed to demonstrate whether safer sexual practices can reduce transmission.

Detection of human herpesvirus 8 DNA in serum from blood donors with HHV-8 antibodies indicates possible bloodborne virus transmission.

Human herpesvirus 8 (HHV-8) is associated with Kaposi's sarcoma. There is a high seroprevalence of HHV-8 in several African countries, but the transmission route is not known definitively. In this study 174 serum samples from blood donors in Tanzania were examined by immunofluorescence assays detecting antibodies to latent and lytic HHV-8 antigens. Real-time polymerase chain reaction was used for detection and quantification of HHV-8 DNA in serum. In all, 83/174 (48%) of the subjects had antibodies to latent or lytic antigens. Forty (23%) had antibodies to both antigens and of those eight (20%) had detectable HHV-8 DNA in serum. HHV-8 DNA load correlated with antibody titres to lytic, but not latent, HHV-8 antigens. This supports the usefulness of anti-lytic antibodies in HHV-8 serology and suggests that transmission of HHV-8 by blood contact could be of importance in this region.

High prevalence of human herpesvirus 8 (HHV-8) infection in south Texas children.

Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus, is etiologically associated with Kaposi's sarcoma and other rare malignancies. HHV-8 infection is common in certain areas of Africa and Italy, but occurs in only 0-15% of populations in North America and Europe. The epidemiology and prevalence of HHV-8 infection among children in the United States has not been determined, but is assumed to be low based on limited studies. The objective of this study was to determine the seroprevalence and possible risk factors of HHV-8 infection in children living in south Texas. Questionnaire data were collected and HHV-8 serologic tests were performed from a consecutive, non-probability sample of 123 healthy children (ages 4-13 years) attending general pediatric clinics in south Texas. Serum was tested for HHV-8 antibodies by latent immunofluorescence assay and ORF65 enzyme-linked immunosorbent assay confirmed by immunoblot. HHV-8 prevalence and 95 percent confidence intervals were calculated using standard epidemiologic methods. Logistic regression was used to assess independent risk factors associated with HHV-8 seropositivity. The overall prevalence of HHV-8 infection was 26%. No statistically significant associations were exhibited between HHV-8 prevalence and the variables under study. The prevalence of HHV-8 infection among children in south Texas, particularly among those under the age of 12 years, indicates that non-sexual transmission of this virus is likely to occur among this population. Future investigations of larger study samples will be necessary to develop an understanding of specific routes and risk factors of HHV-8 transmission among children in south Texas.

Risk factors for human herpesvirus 8 infection in a cohort of drug users in the Netherlands, 1985-1996.

To elucidate the mode of human herpesvirus 8 (HHV-8) transmission in a population of Amsterdam drug users, HHV-8 seroprevalence and seroincidence were determined in 1179 drug users in the Amsterdam Cohort Studies (1985-1996). Risk factors for HHV-8 infection were examined. Serum samples were screened with an enzyme immunoassay by using HHV-8 lytic capsid (open-reading frame [ORF] 65) and latent nuclear (ORF73) antigens; positive results were confirmed by Western blot and immunofluorescence assay. Seroprevalence (men, 3.4%; women, 1.4%) and seroincidence (men, 0.08; women, 0.05/100 person-years) were low in this study. Infections with human immunodeficiency virus (HIV) type 1, hepatitis B virus (HBV), and hepatitis C virus (HCV), but not HHV-8, were associated with injection drug use (IDU). Independent risk factors for HHV-8 seropositivity were homosexual contacts and Mediterranean nationality for men and sexual contact with bisexual men, absence of a steady partner, and unprotected commercial sex for women. Unlike HIV-1, HBV, or HCV infection, HHV-8 infection is uncommon in Amsterdam drug users, as is HHV-8 transmission through IDU.

HHV-8 Infection in the Transplantation Setting: A Concern Only for Solid Organ Transplant Patients?

Early epidemiologic studies have shown an increased risk of Kaposi sarcoma (KS) in recipients of solid organ transplants, while KS is exceptional in the setting of autologous and allogeneic bone marrow (BM) and peripheral blood stem cell (PBSC) transplant patients. The recent discovery of human herpesvirus 8 (HHV-8) as the necessary etiologic agent of KS has stimulated studies to assess whether KS is the result of HHV-8 transmission from the donor or of reactivation of a pre-existing HHV-8 infection in the recipient host. An association of HHV-8 infection with lymphoid neoplasias has also been observed, identifying this herpesvirus as a possible causal agent of some Epstein-Barr virus negative post-transplant lymphoproliferative diseases. The recent description of non-neoplastic complications associated with HHV-8 reactivation after autologous PBSC transplantation, has raised concerns about the spectrum of diseases potentially associated with this herpesvirus, even in the setting of BM and or PBSC transplantation. The issue of HHV-8 transmission with the grafts, the problems inherent with the diagnosis and monitoring of active viral infection, the need for prevention and treatment of the clinical consequences of HHV-8 primary infection and reactivation cannot be underestimated, at least in areas endemic for HHV-8 infection.

Detección del virus herpes humano tipo 8 en sarcoma de Kaposi, mieloma múltiple y síndromes linfoproliferativos en pacientes con inmunodepresión y sin ella

The purposes of this study were: to study the presence of human herpesvirus-8 (HHV-8) in different Kaposi's sarcoma (KS) epidemiological groups, multiple myeloma (MM), and immunodeficiency-associated lymphoid proliferations; to investigate the potential sexual transmission of HHV-8 by analyzing its presence in women from the general population, human immunodeficiency virus (HIV) seropositive women, and prostitutes; and to establish a reliable and efficient PCR strategy for the detection of HHV-8. HHV-8 detection was performed by PCR and positive cases were confirmed by automatic bi-directional sequencing. We selected 25 KS, 70 immunodeficiency associated non-Hodgkin's lymphomas (NHL), 30 HIV-positive Hodgkin's lymphomas (HL), and 2 primary effusion lymphomas (PEL). Bone marrow aspirates were available from 41 MM, 9 monoclonal gammopathies of undetermined significance and 24 patients with other disorders. Bone marrow dendritic cell cultures from 12 MM patients were also performed. Cells from cervical, anal, and oral cavity scrapes were examined for the presence of HHV-8 in 40 control women, 10 HIV-seropositive women, and 20 HIV-seronegative prostitutes. Serologic tests were also performed. HHV-8 was specifically detected in 100% KS and PEL, and in 5.7% immunodeficiency associated NHL. All cases of HIV-HL and MM were HHV-8 negative. Antibodies against HHV-8 were found in 10% of control women, 10% HIV-positive women, and 25% prostitutes. Only 1 sample was positive for HHV-8 by PCR. HHV-8 is associated with all epidemiological forms of KS; HHV-8 does not contribute to the pathogenesis of MM, and this virus is not ubiquitous in the human population. Seroprevalence of HHV-8 is increased in prostitutes, although this may partially be attributed to the geographical origin. For a reliable PCR detection of HHV-8, it is necessary to target different regions of the viral genome and to sequence amplification products.

Seroprevalence of human herpes virus 8 antibody in populations at high or low risk of transfusion, graft, or sexual transmission of viruses.

The routes of transmission of human herpes virus 8 (HHV-8) remain unclear. In particular, HHV-8 transmission by blood components and organ transplantation is still debated and raises public health issues. The objective of this study was to determine the prevalence of anti-HHV-8 in selected populations of persons or patients with or without risk factors for the transmission of viral infections, in order to determine the routes of HHV-8 transmission. A total of 1431 persons or patients at low or high risk of sexually, blood-, or graft-transmitted viral infections were tested by means of a standardized immunofluorescence serologic assay detecting anti-HHV-8. The persons or patients could be classified into three distinct groups according to anti-HHV-8 prevalence: a low prevalence group (0.0% to 5.0%), including healthy blood donors, healthy pregnant women, multiply transfused patients with thalassemia major, and IV drug users; an intermediate prevalence group (5.0% to 20.0%), including organ donors, kidney transplant recipients, and multiply transfused patients with sickle cell disease; a high prevalence group (>20.0%), including HIV-negative persons at high risk of sexually-transmitted viral infections, and HIV-infected homosexual men and heterosexuals. The sexual route appears to be the main route of HHV-8 transmission; bloodborne transmission of HHV-8, if it exists, is rare. In contrast, organ transplantation recipients might be exposed to HHV-8 transmission by the transplanted organ, which raises the issue of systematic screening of organ donors.

Human herpesvirus 8 and oral health care: An update

The purpose of this report was to review the current literature on human herpesvirus 8 (HHV-8) with particular attention to the aspects of interest for dental health care workers. The authors searched original research and review articles on specific aspects of HHV-8 infection, including virology, epidemiology, transmission, diagnosis, natural history, therapy, and oral aspects. The relevant material was evaluated and reviewed. HHV-8 is a recently discovered DNA virus that is present throughout the world but with major geographic variation. In the Western world, the virus, transmitted mainly by means of sexual contact, is strongly associated with Kaposi's sarcoma and body cavity-based lymphoma and more controversially with multiple myeloma and non-neoplastic disorders. There is no specific effective treatment, but human immunodeficiency virus protease inhibitors may play an indirect role in the clearance of HHV-8 DNA from peripheral blood mononuclear cells of patients infected with human immunodeficiency virus. HHV-8 DNA is present in saliva, but as yet, there are no documented instances of nosocomial transmission to health care workers. The prevalence of HHV-8 among dental health care workers is probably similar to that in the general population. HHV-8 does not appear to be ubiquitous in most populations, particularly in western Europe and the United States, where it may be restricted to a population at risk of having Kaposi's sarcoma develop (men infected with human immunodeficiency virus and patients who are iatrogenically immunosuppressed). Most serologic studies suggest a global HHV-8 seroprevalence of 2% to 10% and show that the virus may be under immunologic control in people who are healthy but infected with HHV-8. Also, HHV-8 certainly has the means to overcome cellular control and immune responses and thus predispose to malignancy. To date, there are no data to suggest that health care staff members are at particular risk of HHV-8 acquisition through occupational routes.

Kaposi's sarcoma in South Africa.

Kaposi's sarcoma was endemic in South Africa even before the advent of the human immunodeficiency virus (HIV). Between 1988 and 1996, the incidence of Kaposi's sarcoma in South Africa has risen at least threefold and continues to increase as the HIV epidemic grows. Research from South Africa has shown that infection with human herpesvirus 8 (HHV8) is associated with Kaposi's sarcoma but not with any other major cancer site or type. In addition, the risk of Kaposi's sarcoma increases with increasing antibody titer to HHV8, but, for a given titer, the risk is greater in HIV-seropositive compared with HIV-seronegative individuals. The age- and sex-standardized seroprevalence of HHV8 in black South African hospital patients was found to be slightly more than 30%; the seroprevalence of HHV8 increased with age and was similar in men and in women. The modes of transmission of HHV8 are yet to be fully elucidated. Limited evidence exists for sexual transmission in black South African adults, but mother-to-child and person-to-person transmission in childhood is also likely. Furthermore, the seroprevalence of HHV8 decreases with increasing levels of education and is lower in whites than in blacks, suggesting that factors associated with poverty may be important determinants of transmission. Future research should focus on risk factors for Kaposi's sarcoma in HHV8-infected individuals, on determinants and mode of transmission of HHV8, and on the elucidation of the effect of primary HHV8 infection in adults and in children.

Human herpesvirus-8 infection among heterosexual partners of patients with classical Kaposi's sarcoma.

DNA sequences of human herpesvirus-8 (HHV8) are found in lesions of Kaposi's sarcoma (KS). To verify the hypothesis of the sexual transmission of HHV8 infection. We used the immunoperoxidase assay to study the prevalence of serum antibodies to HHV8-related antigens in 27 consorts of patients with classical KS, and in a control group of 25 healthy women. Forty-four per cent of the study group were positive, compared with 8% of the controls. The sexual route may be one of the possible ways of transmission of the HHV8 virus.

Molecular evidence of organ-related transmission of Kaposi sarcoma–associated herpesvirus or human herpesvirus-8 in transplant patients

In transplant patients, Kaposi sarcoma (KS)-associated herpesvirus or human herpesvirus-8 (HHV-8) infection is associated with the development of KS, primary effusion lymphoma and Castleman disease. Whether HHV-8 is either reactivated in the recipient or transmitted by the donor has been investigated so far only by serologic studies. Thus, we addressed the issue of HHV-8 transmission in the transplantation setting by molecular methods. We exploited the high level variability of the orf-K1 gene and the polymorphism of the orf-73 gene of the HHV-8 genome to assess the genetic relatedness of the HHV-8 strains identified in the posttransplant KS lesions that developed, simultaneously, 20 months after transplantation, in 2 recipients of twin kidneys from the same cadaver donor. The 100% identity of nucleotide sequence of the most variable viral region and the presence of the same, single orf-73 type in both patients provides strong molecular evidence of organ-related transmission of HHV-8 in the setting of transplantation.

Human herpesvirus 8 transmission from mother to child and between siblings in an endemic population

Transmission of human herpesvirus 8 (HHV-8), the aetiological agent of Kaposi's sarcoma, is known to occur during sex among homosexual men. However, other modes of HHV-8 transmission remain to be elucidated in endemic populations. We did a population-based seroepidemiological survey in a village in French Guiana among 1337 individuals of African origin (age 2-91 years) who had reliable genealogical data. Plasma samples were taken and tested for HHV-specific IgG by immunofluorescence assay. Risk factors and familial correlations for HHV-8 seropositivity were modelled by logistic regression analysis by use of the estimating equations approach, which expresses familial dependences in terms of odds ratios. Familial odds ratios were also acquired by use of the distribution of all possible pairs of a given familial dependence. The overall HHV-8 seroprevalence was 13.2% with no difference according to sex. HHV-8 seropositivity was strongly age dependent: at 1.2% under 5 years, HHV-8 seroprevalence rose up to a plateau around 15% between 15 and 40 years, and showed a seroprevalence of more than 27% in individuals older than 40 years. Strong familial aggregation in HHV-8 seroprevalence was found with high mother-child (odd ratio 2.8 [95% CI 1.6-5.0]) and sib-sib (3.8 [1.6-9.5]) correlations. By contrast, no significant correlation between spouses (0.6 [0.2-1.9]) was seen. This pattern of familial aggregation, together with the variation of HHV-8 seroprevalence with age, indicate that, in endemic populations, HHV-8 transmission mainly occurs from mother to child and between siblings during childhood and adolescence.

Seropositivity to human herpesvirus 8 in relation to sexual history and risk of sexually transmitted infections among women

The mode of transmission of human herpesvirus 8 (HHV8) was investigated in two seroepidemiological studies of Swedish women who completed a questionnaire about sexual behavior. Seropositivity for HHV8 antibodies, measured using an indirect immunofluorescence assay, was linked to a high number (>10) of sexual partners (P < 0.004). It also correlated strongly with a history of other sexually transmitted diseases (STD; P < 0.0001), in particular with a history of Chlamydia trachomatis infection and condyloma acuminata. There was appreciable HHV8 seropositivity already among virginal or monogamous women (9%). In summary, HHV8 transmission to women in Sweden may occur nonsexually. When sexual transmission occurs, it appears to be associated with high risk-taking sexual behavior. Int. J. Cancer 87:232–235, 2000. © 2000 Wiley-Liss, Inc.

Human herpesvirus 8 and Kaposi's sarcoma in persons infected with human immunodeficiency virus.

Human herpesvirus 8 (HHV-8) was detected in 1994 in biopsies of Kaposi's sarcoma (KS) tissues from a patient with AIDS. The evidence that HHV-8 infection is etiologically related to the development of KS is compelling. Essentially all patients with KS of any epidemiological type have serological evidence of HHV-8 infection. About 30%-40% of homosexual men infected with human immunodeficiency virus (HIV) are seropositive for HHV-8; rates are lower (<10%) among HIV-infected women, hemophiliacs, and injection drug users. Among homosexual men, the probability of HHV-8-seropositivity is directly proportional to the numbers of previous male sex partners, which suggets that HHV-8 is a sexually transmitted infection. Although HHV-8 is detectable in saliva and semen, the exact mechanism of transmission is not known. A reduction in KS incidence among patients with AIDS in the 1980s has been attributed to lower rates of HHV-8 transmission that resulted from alterations in sexual behaviors. A further decline in KS incidence has been associated with the use of antiretroviral therapy. Antiretroviral therapy to control HIV replication and to limit the associated immunodeficiency is currently the best approach for preventing KS in persons infected with HHV-8 and HIV.

Invited Commentary: Determining Specific Sexual Practices Associated with Human Herpesvirus 8 Transmission

Laboratory and epidemiologic studies have established human herpesvirus 8 (HHV8) as an etiologic agent of Kaposi's sarcoma. With strong evidence linking HHV8 infection with the number of sexual partners among homosexual men, the challenge now is to determine the specific sexual acts associated with HHV8 transmission. Initial studies of specific practices, however, have differed in their conclusions; the paper by Dukers et al. in this issue of the Journal is the first to associate penile-oral intercourse with HHV8 transmission. Many sources of bias may contribute to the conflicting findings of studies reported to date: HHV8 research still lacks an adequately specific and sensitive serologic assay; identification of relevant exposure periods and measurement of sexual practices are imperfect; and sufficient adjustment for confounding is problematic. These numerous potential biases may be particularly important when trying to detect underlying associations that may be of low-order magnitude. The study by Dukers et al. (Am J Epidemiol 2000;151:213-24) is an important contribution to research on HHV8 transmission, but we do not yet know enough about the possible sexual routes of transmission to recommend avoiding any single behavior. For now, the best prevention advice is to reinforce the more general safe sex practices that have been promoted to prevent human immunodeficiency virus and other sexually transmitted diseases.

Risk factors for human herpesvirus 8 seropositivity and seroconversion in a cohort of homosexual men.

Sexual and nonsexual modes of transmission of human herpesvirus 8 (HHV8) have been suggested, but specific routes remain unclear. Therefore, the objective of this study was to assess risk factors for HHV8 seropositivity and determine specific sexual practices associated with HHV8 seroconversion. Sera from 1,458 homosexual men (Amsterdam Cohort Study, 1984-1996) were tested for antibodies to HHV8 with a modified version of an enzyme immunoassay, using recombinant HHV8 lytic phase capsid (ORF65) and latent phase nuclear (ORF73) proteins. HHV8 seroprevalence at study entry was 20.9% (305/1,458); was highest among those with positive human immunodeficiency virus (HIV) status, no steady partner, and southern European or Latin American nationality; and increased with older age and higher number of sexual partners. During follow-up, 215 men seroconverted for HHV8 (incidence: 3.6/100 person-years). Both prevalence and incidence rates remained more or less stable during the study period. Orogenital insertive sex (odds ratio (OR) = 5.95; 95% confidence interval (CI): 2.88, 12.29) or orogenital receptive sex (OR = 4.29; 95% CI: 2.11, 8.71) with more than five partners in the past 6 months, older age (OR = 2.89; 95% CI: 1.13, 7.34, when older than 45 years), and preceding HIV infection (OR = 2.47; 95% CI: 1.53, 3.99) were independent predictors for HHV8 seroconversion. The authors found strong evidence for orogenital transmission of HHV8 among homosexual men.

A search for human herpesvirus 8(HHV-8) in HIV-1 infected mothers and their infants does not suggest vertical transmission of HHV-8

A search for human herpesvirus 8(HHV-8) in HIV-1 infected mothers and their infants does not suggest vertical transmission of HHV-8

Transfusion-Associated Infections with Cytomegalovirus and Other Human Herpesviruses

Of all human herpesviruses, human cytomegalovirus (HCMV) is the most significant cause of transfusion-associated (TA) morbidity and mortality. The problem of TA HCMV infection differs from that of other transfusion-transmitted infections in that only certain groups of patients require HCMV-free blood or blood components, i.e. seronegative pregnant women, premature infants of low birth weight who are born to seronegative mothers, seronegative recipients of allogeneic bone marrow transplants from seronegative donors, seronegative AIDS patients, and seronegative immunosuppressed patients in general. HCMV is strictly cell-associated, and transmission appears to be due to reactivation of latent virus in white blood cells. TA HCMV infec-tion in risk groups can be minimized by selection of HCMV-seronegative donors. Since transmission of HCMV from seropositive donors by blood components containing fewer than 10 7 leukocytes per unit is unlikely, leukodepletion of transfusion products by filtration is an effective alternative to the use of seronegative blood products. Other human herpesviruses causing TA infections are Epstein-Barr virus (EBV) and the human herpesviruses 6 and 7 (HHV-6, HHV-7), whereas transmissions of herpes simplex viruses (HSV-1, HSV-2) and varicella-zoster virus (VZV) by blood transfusion – if occurring at all – are extremely rare events. Frequency and clinical significance of TA infections with the human herpesvirus 8 (HHV-8) have not yet been fully elucidated. Despite the low seroprevalence of HHV-8 in Germany, its oncogenic potential merits attention, and strategies to prevent transmission and spread of HHV-8 by blood and blood products should be discussed.