Transmission of Kaposi sarcoma-associated herpesvirus in sub-Saharan Africa

HHV-8 seroprevalence: a global view

BACKGROUND

Human herpes virus 8 (HHV-8) is the underlying infectious cause of Kaposi sarcoma (KS) and other proliferative diseases; that is, primary effusion lymphoma and multicentric Castleman disease. In regions with high HHV-8 seroprevalence in the general population, KS accounts for a major burden of disease. Outside these endemic regions, HHV-8 prevalence is high in men who have sex with men (MSM) and in migrants from endemic regions. We aim to conduct a systematic literature review and meta-analysis in order 1) to define the global distribution of HHV-8 seroprevalence (primary objective) and 2) to identify risk factors for HHV-8 infection, with a focus on HIV status (secondary objective).

METHODS/DESIGN

We will include observational studies reporting data on seroprevalence of HHV-8 in children and/or adults from any region in the world. Case reports and case series as well as any studies with fewer than 50 participants will be excluded. We will search MEDLINE, EMBASE, and relevant conference proceedings without language restriction. Two reviewers will independently screen the identified studies and extract data on study characteristics and quality, study population, risk factors, and reported outcomes, using a standardized form. For the primary objective we will pool the data using a fully bayesian approach for meta-analysis, with random effects at the study level. For the secondary objective (association of HIV and HHV-8) we aim to pool odds ratios for the association of HIV and HHV-8 using a fully bayesian approach for meta-analysis, with random effects at the study level. Sub-group analyses and meta-regression analyses will be used to explore sources of heterogeneity, including factors such as geographical region, calendar years of recruitment, age, gender, ethnicity, socioeconomic status, different risk groups for sexually and parenterally transmitted infections (MSM, sex workers, hemophiliacs, intravenous drug users), comorbidities such as organ transplantation and malaria, test(s) used to measure HHV-8 infection, study design, and study quality.

DISCUSSION

Using the proposed systematic review and meta-analysis, we aim to better define the global seroprevalence of HHV-8 and its associated risk factors. This will improve the current understanding of HHV-8 epidemiology, and could suggest measures to prevent HHV-8 infection and to reduce its associated cancer burden.

A case report of the rapid dissemination of Kaposi’s sarcoma in a patient with HIV

Introduction: Kaposi’s sarcoma is the most common HIV-associated neoplastic disease. In most cases it starts on the skin and later spreads to other visceral organs. We reported a case of HIV-associated cutaneous Kaposi’s sarcoma which rapidly progressed to involve the visceral organs within a few weeks and resulted in fatality. Case presentation: A 21-year old man who recently started antiretroviral therapy developed disseminated Kaposi’s sarcoma with a right-sided pleural effusion. Chest x-ray confirmed the effusion which was tapped for diagnostic purposes. Biopsy confirmed Kaposi’s sarcoma. He insisted on being discharged so that he could visit a traditional healer. Management and outcome: Despite antiretroviral therapy and supportive management his condition deteriorated rapidly and he died within a month of the diagnosis of disseminated Kaposi’s sarcoma. He died before chemotherapy could be commenced. Discussion: The lessons that could be learned from this case include the following: Kaposi’s sarcoma is asymptomatic and, since one out of three are HHV-8 positive, patients should have a thorough examination before starting on highly-active antiretroviral therapy. Patients with Kaposi’s sarcoma or even those on treatment should be warned of deterioration in the first 12 weeks of treatment. Pulmonary Kaposi’s sarcoma is fatal and requires timeous management and chemotherapy. Patients with HIV-related Kaposi’s sarcoma and chest signs require sputa to exclude pulmonary tuberculosis. Finally, traditional healers may be used to assist, especially if they are taught to identify HIV-related skin conditions and can refer patients appropriately.

A population-based study of Kaposi Sarcoma-associated herpesvirus seropositivity in Uganda using principal components analysis

Background

Kaposi sarcoma-associated herpesvirus (KSHV) seropositivity is associated with sexual, environmental, and socioeconomic exposures. Whether these characteristics are independent risk factors is uncertain because of reliance on selected high-risk or hospital-based populations and incomplete adjustment for confounding. Therefore, we evaluated risk factors for KSHV seropositivity in a population-based study in Uganda using principal components analysis (PCA).

Methods

The study population comprised 2,681 individuals randomly selected from a nationally-representative population-based HIV/AIDS sero-behavioral survey conducted in 2004/05. Questionnaire and laboratory data (97 variables) were transformed into a smaller set of uncorrelated variables using PCA. Multivariable logistic regression models were fitted to estimate odds ratios and 95% confidence intervals for the association between components and KSHV seropositivity.

Results

Data were reduced to three principal components (PCs) labeled as Sexual behavioral, Socioeconomic, and Knowledge PCs. In crude analysis, KSHV seropositivity was associated with the Knowledge (p_trend = 0.012) and Socioeconomic components (p_trend = 0.0001), but not with the Sexual-behavioral component (p_trend = 0.066). KSHV seropositivity was associated with the Socioeconomic PC (p_trend = 0.037), but not with the Sexual-behavioral and Knowledge PCs, in the models including PCs, age, gender and geographic region.

Conclusions

Our results fit with the view that in Uganda socioeconomic characteristic may influence KSHV seropositivity. Conversely, the results fit with the interpretation that in Uganda sexual-behavioral characteristics, if relevant, contribute minimally.

Human herpesvirus 8 seropositivity among sexually active adults in Uganda

Introduction

Sexual transmission of human herpesvirus 8 (HHV8) has been implicated among homosexual men, but the evidence for sexual transmission among heterosexual individuals is controversial. We investigated the role of sexual transmission of HHV8 in a nationally representative sample in Uganda, where HHV8 infection is endemic and transmitted mostly during childhood.

Materials and Methods

The study population was a subset of participants (n = 2681) from a population-based HIV/AIDS serobehavioral survey of adults aged 15–59 years conducted in 2004/2005. High risk for sexual transmission was assessed by questionnaire and serological testing for HIV and herpes simplex virus 2. Anti-HHV8 antibodies were measured using two enzyme immunoassays targeting synthetic peptides from the K8.1 and orf65 viral genes. The current study was restricted to 2288 sexually active adults. ORs and 95% CIs for HHV8 seropositivity were estimated by fitting logistic regression models with a random intercept using MPLUS and SAS software.

Results

The weighted prevalence of HHV8 seropositivity was 56.2%, based on 1302 seropositive individuals, and it increased significantly with age (P_trend<0.0001). In analyses adjusting for age, sex, geography, education, and HIV status, HHV8 seropositivity was positively associated with reporting two versus one marital union (OR:1.52, 95% CI: 1.17–1.97) and each unit increase in the number of children born (OR: 1.04, 95% CI: 1.00–1.08), and was inversely associated with ever having used a condom (OR: 0.64, 95% CI: 0.45–0.89). HHV8 seropositivity was not associated with HIV (P = 0.660) or with herpes simplex virus 2 (P = 0.732) seropositivity. Other sexual variables, including lifetime number of sexual partners or having had at least one sexually transmitted disease, and socioeconomic variables were unrelated to HHV8 seropositivity.

Conclusion

Our findings are compatible with the conclusion that sexual transmission of HHV8 in Uganda, if it occurs, is weak.

Sex and geographic patterns of human herpesvirus 8 infection in a nationally representative population‐based sample in Uganda

BACKGROUND

Human herpesvirus 8 (HHV8), the infectious cause of Kaposi sarcoma, varies dramatically across Africa, suggesting that cofactors correlated with large-area geographic or environmental characteristics may influence risk of infection. Variation in HHV8 seropositivity across small-area regions within countries in Africa is unknown. We investigated this issue in Uganda, where Kaposi sarcoma distribution is uneven and well described.

METHODS

Archival samples from individuals aged 15-59 years randomly selected from a nationally representative 2004-2005 human immunodeficiency virus-AIDS serobehavioral survey were tested for HHV8 seropositivity with use of enzyme immunoassays based on synthetic peptides from the K8.1 and orf65 viral genes. Adjusted odds ratios and 95% confidence intervals (CIs) of association of HHV8 seropositivity with demographic risk factors were estimated.

RESULTS

Among 2681 individuals tested, HHV8 seropositivity was 55.4%. HHV8 seropositivity was lower in female than in male persons (adjusted odds ratio, 0.82 [95% CI, 0.69-0.97]) and increased 2.2% (95% CI, 1.0%-3.6%) in female persons and 1.2% (95% CI, 1.0%-2.3%) in male persons per year of age. HHV8 seropositivity was inversely associated with education ( P = .01, for trend) and was elevated in the West Nile region, compared with the Central region (adjusted odds ratio, 1.49 [95% CI, 1.02-2.18]) but not with other regions.

CONCLUSIONS

Our findings suggest that HHV8 seropositivity in Uganda may be influenced by cofactors correlated with small-area geography, age, sex, and education.

Lack of evidence for frequent heterosexual transmission of human herpesvirus 8 in Zimbabwe

BACKGROUND

There is conflicting evidence about the contribution of heterosexual transmission to the spread of human herpesvirus 8 (HHV-8) in southern Africa. This study evaluated the hypothesis that HHV-8 infection is associated with risk factors for human immunodeficiency virus type 1 (HIV-1) and other sexually transmitted infections among Zimbabwean men.

METHODS

HHV-8 seroprevalence was determined for 2750 participants in the Zimbabwe AIDS Prevention Project cohort of male factory workers in Harare, Zimbabwe. Potential associations of HHV-8 antibody detection with risk factors for HIV-1 infection were examined by univariate analysis. Variables with P < .1 in the univariate analysis were included in a multivariate logistic regression model. HHV-8 seroprevalence was also determined among 297 heterosexual couples.

RESULTS

Prevalence of HHV-8, HIV-1, and HHV-8 and HIV-1 coinfection was 28.5% (95% confidence interval [CI], 26.8%-30.2%), 19.5% (95% CI, 18.0%-20.9%), and 6.5% (95% CI, 5.6%-7.5%), respectively. Detection of HHV-8 antibodies was independently associated with older age and HIV-1 infection but not with number of recent sex partners, marital status, education, condom use, prior sexually transmitted infections, payment for sex, chronic hepatitis B infection, or incident HIV-1 infection. HHV-8 seroprevalence was 31.7% (95% CI, 26.3-37.0) among wives in the couples tested, but HHV-8 infection of wives was not associated with HHV-8 infection of husbands (odds ratio, 1.08; 95% CI, 0.62-1.88; P = .8).

CONCLUSIONS

HHV-8 and HIV-1 infection did not have common sexual risk factors among urban Zimbabwean men. Sexual transmission does not explain the high prevalence of HHV-8 in this population.