Prevalence of Kaposi’s sarcoma-associated herpesvirus among intravenous drug users: a systematic review and meta-analysis

  • Qiwen Fang ,

    #These authors contributed equally to this work.

    Affiliation Department of Epidemiology, School of Public Health, Fudan University, Shanghai 200032, China,
    Key Laboratory of Public Health Safety, Fudan University, Ministry of Education, Shanghai 200032, China

  • Zhenqiu Liu ,

    #These authors contributed equally to this work.

    Affiliation Department of Epidemiology, School of Public Health, Fudan University, Shanghai 200032, China

  • Zhijie Zhang,

    Affiliation Department of Epidemiology, School of Public Health, Fudan University, Shanghai 200032, China

  • Yan Zeng ,

    yzeng910@163.com

    Affiliation Department of Biochemistry and Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University School of Medicine, Shihezi 832002, China

    http://orcid.org/0000-0002-2396-2830

  • Tiejun Zhang

    tjzhang@shmu.edu.cn

    Affiliation Department of Epidemiology, School of Public Health, Fudan University, Shanghai 200032, China,
    Collaborative Innovation Center of Social Risks Governance in Health, Fudan University, Shanghai 200032, China

    http://orcid.org/0000-0002-5187-7393

Prevalence of Kaposi’s sarcoma-associated herpesvirus among intravenous drug users: a systematic review and meta-analysis

  • Qiwen Fang, 
  • Zhenqiu Liu, 
  • Zhijie Zhang, 
  • Yan Zeng, 
  • Tiejun Zhang
x

Abstract

Intravenous drug users (IDUs) have been demonstrated to be highly vulnerable to HIV/AIDS. Nevertheless, the prevalence of Kaposi’s sarcoma associated herpesvirus (KSHV), an important co-infected agent with HIV, among this population remained obscure. We conducted a systematic review on the epidemiological features of KSHV among IDUs worldwide. Eligible studies were retrieved from 6 electronic databases (PubMed, EMBASE, Web of Science, CBM, CNKI and Wanfang). We calculated the pooled prevalence and 95% confidence interval (CI) overall and among subgroups using either random-effects model or fixed-effects model depending on between-study heterogeneity. The potential publication bias was assessed by the Egger’s test. A meta-regression analysis was performed to explore the sources of heterogeneity. Finally, twenty-two studies with a total sample of 7881 IDUs were included in the analysis. The pooled prevalence of KSHV was 14.71% (95% CI 11.12%–19.46%) among IDUs. Specifically, KSHV prevalence was 10.86% (95% CI 6.95%–16.96%) in HIV-negative IDUs, and 13.56% (95% CI 10.57%–17.38%) in HIV-positive IDUs. Moreover, prevalence among IDUs from the three continents involved in the current study was similar: 16.10% (95%CI 7.73%–33.54%) in Asia; 14.22% (95%CI 8.96%–22.57%) in Europe and 14.06% (95%CI 11.38%–17.37%) in America. Globally, IDUs are at higher risk of the KSHV infection when compared with the general population, regardless of geographical region or HIV-infection status.

INTRODUCTION

Kaposi’s sarcoma-associated herpesvirus (KSHV), also known as Human herpesvirus 8 (HHV8), a member of the gamma herpesvirus family, is the infectious etiological agent associated with all forms of Kaposi’s sarcoma (KS), primary effusion lymphoma (PEL) and multicentric Castleman’s disease (Razonable, 2011; Zhang et al., 2017). Since its first discovery in 1994(Chang et al., 1994), KSHV has been well studied worldwide (Schwartz et al., 2008; Bagni and Whitby, 2009). Unlike most herpes viruses, KSHV infection is not ubiquitous in the general population. In Asia, North America and West Europe, the prevalence is about 1–10% (Zhang et al., 2014b; Ahmadi Ghezeldasht et al., 2015). However, previous studies have demonstrated that KSHV was endemic in parts of Africa and Mediterranean region, with the prevalence varied from 30% to 50% above (Whitby et al., 1998; Biryahwaho et al., 2010). These studies were of indicative disparities of KSHV prevalence among different geographical regions. Moreover, it has been well documented that HIV was the most important factor associated with KSHV infection (Zhang et al., 2012; Rohner et al., 2016; Liu et al., 2017b), especially in the men who have sex with men (MSM), among whom KSHV has been extensively investigated and some convincible results were obtained. However, among intravenous drug users (IDUs), a population at high risk of HIV infection, results of KSHV infection derived from previous studies were quite diverse. Atkinson et al (Atkinson et al., 2003) reported that KSHV prevalence was 10% in men who practicing intravenous drug use, which was much lower than our previous result (Zhang et al., 2014a). Undoubtedly, the considerable variability of KSHV infection among IDUs (Simpson et al., 1996; Rezza et al., 1998; Wang et al., 2000; Lee et al., 2014) hampered the accurate understanding of KSHV epidemiology in this special population.

Therefore, we, for the first time, performed a comprehensive meta-analysis to obtain the global prevalence of KSHV among IDUs. These results will accelerate the completion of picture depicting the epidemiology of KSHV among IDUs, and assist the better understanding of KSHV transmission route.

MATERIALS AND METHODS

Search strategy

We conducted a comprehensive search of literature in Medline (PubMed), EMBASE, Web of Science, the Chinese Biomedical Literature Database (CBM), the China National Knowledge Infrastructure Database (CNKI) and Wanfang Database. The search strategy was listed in Supplementary Table S1. The references of reviews were also examined to search for additional eligible studies.

Inclusion and exclusion criteria

Studies were eligible if they fulfilled the following criteria: 1) reporting data on prevalence of KSHV infection (a positive result for antigens or virus DNA) among IDUs (drug users who ever had an injecting history) from any region in the world; 2) testing KSHV antibodies or DNA for virus detection; 3) cohort studies, case-control studies, cross-sectional surveys, or randomized controlled trials documenting the prevalence of KSHV infection with a minimum sample size of 50 participants in total. We excluded publications that were: 1) of which study population covered by other articles from the same research group; 2) non-original studies (including commentaries, reviews, meta-analyses, correspondence, editorials); 3) lacking of sufficient information.

The titles retrieved from this research were reviewed independently by two researchers (QF and ZL). The third researcher was involved in the decision-making in case of any disagreement. At least three authors (including first author) further reviewed the abstracts and full texts of the included papers before making a final decision on which studies to be included in this meta-analysis. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) statement was followed as a guideline for conducting this systematic review and meta-analysis.

Data extraction

The following information was extracted from each study: first author, year of publication, study location (country, continent), testing method of KSHV, age range and gender distribution of the participants, number of KSHV-positive cases and sample size of the IDUs (total and stratified by HIV-infected status). If any data essential to the analysis were not available for a study, best efforts were made to contact the authors to obtain the missing data. Two researchers extracted the information independently. Inconsistencies were resolved by examining the original paper and discussing the discrepancy until a consensus was reached.

Statistical analysis

The number of KSHV infected cases and all participants in each study were combined to obtain a pooled proportion and 95% confidence interval (CI). Subgroup analysis was conducted to aggregate the prevalence among IDUs with different HIV-infection status and from different continents. The overall prevalence was presented via forest plots. Considering the variance stabilization, 0.5 was added to event number and sample size of studies with an event probability of either 0 or 1 and log-transformation of the original prevalence was implemented to calculate an overall prevalence according to the Shapiro-Wilk normality test (Luo et al., 2013). Heterogeneity across the included studies was tested using the Q-test, and the results were considered statistically significant when P < 0.1. I2 metric was also used to quantify heterogeneity. When the effects were assumed to be homogeneous (P > 0.1, I2 < 25%), the fixed-effects model was used; otherwise, the random-effects model was applied. Between-study heterogeneity, if existed, was further explored using meta-regression analysis, in which we evaluated the effect of variables included in the data extraction form. Dummy variables were created for the categorical variables. Publication bias was examined with funnels plots, which showed a scatter plot of studies included in the meta-analysis. An asymmetrical appearance of dots in the funnel plots can be regarded as a proof of publication bias. Egger weighted regression methods (Egger’s test) were used to statistically assess publication bias. All analyses were performed using R package Meta (Version 4.8-2) and Metafor (version 2.0-0). A two tailed P < 0.05 was considered statistically significant, unless otherwise specified.

RESULTS

Studies included in the meta-analysis

A total of 193 abstracts were retrieved after duplicates were removed. Through preliminary screening of their titles and abstracts, we excluded 149 studies due to irrelevance and undesirable study design. After further full-text reading, additional 22 studies were excluded. A full PRISMA record management flow chart was presented in Figure 1. Finally, twenty-two studies were eligible for this meta-analysis according to the inclusion and exclusion criteria. A total of 7881 IDUs, involving 3611 HIV-uninfected and 2504 HIV-infected individuals, were included (Table 1). Variables, such as age and gender, were not shown in Table 1 or subsequently analyzed in the meta-regression due to the scarcity of original data.

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Fig 1. Flow chart of the study selection process and specific reasons for exclusion from meta-analysis.

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Table 1. The detailed characteristics of all eligible studies
Authors Year Continent(Country) Testing Method KSHV positivity (No. of positive sera/No. of tested sera)
Total HIV-positive HIV-negative
Khajedaluee et al. 2016 Asia (Iran) ELISA 8/111
Kakavand-Ghalehnoei et al. 2016 Asia (Iran) PCR 8/60
Lee et al. 2014 Asia (China) ELISA 27/553 25/377 2/176
Zhang et al. 2014 Asia (China) IFA 56/296
Zavitsanou et al. 2010 Europe (Greece) ELISA 70/288 67/286
Yang et al. 2010 Asia (China) ELISA 58/203
Larocca et al. 2005 Europe (Italy) IFA 14/134 8/32 6/102
Bernstein et al. 2003 America (US) IFA 45/390 38/294 7/96
Atkinson et al. 2003 America (US) ELISA 218/1905 55/233 163/1672
Goedert et al. 2003 America (US) ELISA 14/137 14/137
Parisi et al. 2002 Europe (Italy) IFA 13/155 13/155
2002 Europe (Italy) IFA 18/85 18/85
Sosa et al. 2001 America (Argentina) IFA 26/153 25/144 1/9
Greenblatt et al. 2001 America (US) IFA 40/237 35/178 5/59
Gambus et al. 2001 Europe (Spain) IFA 44/382 29/254 15/128
Cannon et al. 2001 America (US) ELISA 141/771
Diamond et al. 2001 America (US) IFA 9/65
Perna et al. 2000 Europe (Italy) IFA 62/374 32/163 30/211
Wang et al. 2000 Asia (China) ELISA 63/107
Rezza et al. 1999 Europe (Italy) IFA 20/133 20/133
Renwick et al. 1998 Europe (The Netherlands) ELISA 89/1167 26/351 63/816
Rezza et al. 1998 Europe (Italy) IFA 55/112 26/47 29/65
Simpson et al. 1996 Europe (UK) ELISA 2/63 2/38 0/25

Prevalence estimates

The pooled prevalence of KSHV among IDUs was 14.71% (95% CI 11.12%– 19.46%), varied from 3.17% to 58.88% across included studies. Random-effects model was applied because of the significant between-study heterogeneity (I2 = 96%; P < 0.01) (Figure 2). In those free of HIV, the pooled KSHV prevalence was 10.86% (95% CI, 6.95%–16.96%; I2 = 94%; P < 0.01), varied from1.14% to 44.62% (Supplementary Figure S1a), while in those infected HIV, the pooled KSHV prevalence was 13.56% (95% CI, 10.57%–17.38%; I2 = 83%; P < 0.01), varied from 6.63% to 23.61% (Supplementary Figure S1b).

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Fig 2. Pooled prevalence of KSHV infection among intravenous drug users.

To explore geographical diversity of KSHV distribution, the variability across different regions was assessed as well (Figure 3). Overall, the pooled KSHV prevalence among IDUs in the three continents involved in the present meta-analysis was 16.10% (95%CI 7.73%–33.54%) in Asia, 14.22% (95%CI 8.96%–22.57%) in Europe, 18.24% (95%CI 11.63%–28.61%) in the Mediterranean part and 14.06% (95%CI 11.38%–17.37%) in America, respectively. There is no significant difference in the KSHV prevalence amongst these geographical regions.

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Fig 3. Subgroup analysis of the pooled prevalence of KSHV infection according to study location.

Publication bias and meta-regression analysis

No publication bias was detected in terms of Egger’s test (t = –1.37, P = 0.18), and the shape of the funnel plots did not reveal any evidence of asymmetry (Figure 4).

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Fig 4. Funnel plot of the KSHV prevalence in the overall population

The variables including publication year, study regions and testing assays were fitted in the multivariate model of meta-regression. None of the three variables proved to be statistically significant (Table 2).

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Table 2. Meta-regression analysis showing influence of variables on the heterogeneity of prevalence (N = 7881)
Standard error Z value P value Regression coefficient (95%CI)
Constant 73.62 1.55 0.12 113.88 (–30.40, 258.17)
Year 0.04 –1.58 0.12 –0.06 (–0.13, 0.01)
Continent
America (reference)
Asia 0.51 1.57 0.12 0.79 (–0.20, 1.79)
Europe 0.33 –0.12 0.91 –0.04 (–0.68, 0.60)
Testing method
ELISA (reference)
IFA 0.31 0.82 0.41 0.25 (–0.35, 0.86)
PCR 0.79 0.16 0.88 0.12 (–1.43, 1.67)

DISCUSSION

In the present meta-analysis, we found a moderately higher KSHV prevalence (14.71%, 95% CI, 11.12%–19.46%) among IDUs in contrast to the general population (Moore, 2000) and no significant difference was detected among subgroups, thereby highlighting the vulnerability of KSHV infection in IDUs regardless of the HIV status and geographical region.

A previous systematic review reported that the KSHV seroprevalence was 47% in HIV-positive population and 24% in HIV-negative population which suggested an increased risk of KSHV seropositivity was associated with HIV-infection (Rohner et al., 2016). In the current study, higher KSHV prevalence was found in HIV positive IDUs than those free of HIV, albeit the difference was not statistically significant. This result might partly be explained by the between-study heterogeneity and also to some extent imply the absolute risk of intravenous drug use for KSHV infection. However, IDUs seem to have a lower KSHV prevalence when compared with MSM (Liu et al., 2017a). According to our pre-published results, KSHV prevalence was approximately double fold in MSM than that in IDUs. This discrepancy might suggest KSHV is much more likely to be transmitted via sexual behaviors while not blood, though controversy remains (Kedes et al., 1996; Vitale et al., 2000; Minhas and Wood, 2014). Since it is difficult to synthesize information on behavior-associated risk factors quantitatively due to the lack of data, the current meta-analysis could not resolve the perplexity precisely. Further studies focusing on more restricted target population, for example, blood donors, transfusion recipients or children without high-risk sexual practice, are warranted.

Moreover, no significant disparity of KSHV prevalence was detected across geographical regions included in this analysis, while according to previous studies, the KSHV infection were deemed to be low in Asia, Europe except Mediterranean regions, and America (Tornesello et al., 2010; Stiller et al., 2014; Zhang and Wang, 2017). An elevated KSHV prevalence was observed within IDUs compared with general population. In the current study, seven studies were from either Italy or Greece, where were endemic of KSHV(Schwartz, 2004). Nevertheless, the KSHV prevalence in Europe was not significantly higher than that in other regions among IDUs. This result may partly ascribe to the between-study heterogeneity, as regional differences have been documented by Whitby et al. in Italy: a low prevalence was reported for the northern part, whereas a prevalence of 35% was detected in Sicily (Whitby et al., 1998). Moreover, since no publication bias was detected in our study, the shrunken gap of KSHV infection among IDUs from different geographical regions compared with general population may also serve as a reminder of the role intravenous drug abuse played in the transmission of KSHV.

Unfortunately, limited information on the KSHV seroprevalence among IDUs in Africa is available, though comprehensive literature research has been performed. Generally, in Africa, particularly the sub-Saharan part, both HIV and HHV8 are endemic (Butler et al., 2009). Therefore, it is not hard to expect an appallingly high KSHV seroprevalence among IDUs, because injection drug use is increasingly contributing to the HIV epidemic across sub-Saharan Africa (Syvertsen et al., 2015). This fact of missing information on the KSHV prevalence among IDUs in Africa highlights the unmet study for KSHV in Africa and calls for wider range of KSHV investigations.

Some limitations of this study should be mentioned. First, significantly higher between-study heterogeneity was noted. A meta-regression was conducted to identify the potential sources, but no significant variable was detected. Second, data from Africa, South America and Australia were not available, thereby undermining the accuracy and representativeness of overall KSHV prevalence. Finally, some variables such as age and sex have not been evaluated in our study due to the dearth of data. Therefore, the pooled results should be interpreted with caution.

In conclusion, the prevalence of KSHV among IDUs was higher compared to general population, regardless of geographical location and HIV-infected status. To our best knowledge, this is the first systematic analysis on the epidemiologic characteristics of KSHV infection among IDUs. It can be used as an important supplement to the existing KSHV data, elucidate the gaps in the epidemiologic characteristics of this virus, as well as provide evidence for changing KSHV prevention practice in the marginalized population. Given the paucity and some limitations of the available studies, more well-designed researches should be performed in the future to depict the epidemiology of KSHV and to enrich the present findings, especially in Africa.

ACKNOWLEDGMENTS

This work was supported by the Natural Science Foundation of Shanghai (17ZR1401400), the Natural Science Foundation of China (grant no. 81772170, U603117) and the Doctoral Fund of Ministry of Education of China (Grant No. 20120071120050).

COMPLIANCE WITH ETHICS GUIDELINES

The author declares no conflict of interest. This article does not contain any studies with human or animal subjects performed by the author.

AUTHOR CONTRIBUTIONS

QWF, ZQL and TJZ designed the experiments. QWF, ZQL and YZ searched literature, collected and summed up the data. QWF, YZ and ZJZ analyzed the data. QWF, ZQL wrote the paper. All authors read and approved the final manuscript.

Supplementary figures/tables are available on the websites of Virologica Sinica: www.virosin.org; link.springer.com/journal/12250.

SUPPLEMENTARY MATERIAL

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Table S1. Search strategy of the databases
Database Search strategy Results
PubMed (prevalen* OR inciden* OR epidemiolog* OR seroprevalen* OR sero-prevalen* OR seroepidemiolog* OR sero-epidemiolog* OR seropositiv* OR sero-positiv* OR seroepidemiologic studies[MeSH] OR prevalence[MeSH] OR incidence[MeSH]) AND (("Drug Users"[Mesh] AND ("Injections, Intravenous"[Mesh] OR "Substance Abuse, Intravenous"[Mesh])) OR ((intraven* OR inject*) AND drug)) AND (("HHV-8" OR "HHV 8" OR "KSHV" OR "Human Herpesvirus 8" OR "Kaposi's Sarcoma-Associated Herpesvirus" OR "Kaposi's Sarcoma Associated Herpesvirus" OR "Kaposis Sarcoma-Associated Herpesvirus" OR "Kaposi Sarcoma-Associated Herpesvirus" OR "Kaposi Sarcoma Associated Herpesvirus") OR "Herpesvirus 8, Human"[Mesh]) 39
EMBASE 1. exp Human herpesvirus 8/ 2. ("human herpesvirus 8" or "hhv-8" or "hhv8" or "kshv" or "kaposi sarcoma associated herpesvirus" or "kaposi’s sarcoma associated herpesvirus" or "kaposi sarcoma-associated herpesvirus" or "kaposi’s sarcoma-associated herpesvirus" or "kaposi NEAR/3 herpesvirus" or "kaposi NEAR/3 virus").mp. [mp=title, abstract, heading word, drug trade name, original title, device manufacturer, drug manufacturer, device trade name, keyword, floating subheading word] 3. exp seroprevalence/ or exp prevalence/ 4. exp seroepidemiology/ 5. exp incidence/ 6. (prevalen* or inciden* or epidemiolog* or sero*epidemiolog* or sero*prevalen* or sero*positiv*).mp. [mp=title, abstract, heading word, drug trade name, original title, device manufacturer, drug manufacturer, device trade name, keyword, floating subheading word] 7. exp intravenous drug abuse/ 8. (drug and (intraven* or inject*)).mp. [mp=title, abstract, heading word, drug trade name, original title, device manufacturer, drug manufacturer, device trade name, keyword, floating subheading word] 9. 1 or 2 10. 3 or 4 or 5 or 6 11. 7 or 8 12. 9 and 10 and 11 162
Web Of Science TOPIC: ("human herpesvirus 8" OR "hhv-8" OR "hhv8" OR "kshv" OR "kaposi sarcoma associated herpesvirus" OR "kaposi’s sarcoma associated herpesvirus" or "kaposi sarcoma-associated herpesvirus" or "kaposi’s sarcoma-associated herpesvirus" or "kaposi NEAR/3 herpesvirus" or "kaposi NEAR/3 virus") AND TOPIC: (prevalen* or inciden* or epidemiolog* or sero*epidemiolog* or sero*prevalen* or sero*positiv*) AND TOPIC: (drug and (intraven* or inject*)) 39
CBM (("herpesvirus 8, human"[weighted: exploded]) OR ("KSHV"[common fields] OR "human herpesvirus 8"[common fields] OR "kaposi sarcoma associated herpesvirus"[common fields] OR "herpesvirus 8, human"[subject terms] OR "HHV-8"[common fields] OR "HHV8"[common fields] OR "herpesvirus 8"[common fields] OR "Kaposi%virus"[common fields]) AND (("Substance Abuse, Intravenous"[unweighted: exploded]) OR ("drug abuse"[common fields]) OR ("drug"[common fields])) (in Chinese) 5
CNKI (SU='KSHV' or SU='HHV-8' or SU='HHV 8' or SU='HHV8' or SU='herpesvirus 8' or SU %'Kapo%virus') and (SU%'drug abuse' or SU%'drug') (in Chinese) 11
Wanfang (Topic:("KSHV or HHV-8 or HHV 8 or herpesvirus 8") + Topic:(Kapo%virus ))* Topic:("drug abuse" or "drug") (in Chinese) 10

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Fig S1. (A) Pooled prevalence of KSHV infection among HIV-negative intravenous drug users. (B) Pooled prevalence of KSHV infection among HIV-positive intravenous drug users.

References

  1. . Ahmadi Ghezeldasht S, Hassannia T, Rafatpanah H, Hekmat R, Valizadeh N, Ghayour Mobarhan M, Rezaee SA. 2015. Oncogenic Virus Infections in the General Population and End-stage Renal Disease Patients With Special Emphasis on Kaposi’s Sarcoma Associated Herpes Virus (KSHV) in Northeast of Iran. Jundishapur J Microbiol, 8: e14920.
  2. . Atkinson J, Edlin BR, Engels EA, Kral AH, Seal K, Gamache CJ, Whitby D, O’Brien TR. 2003. Seroprevalence of human herpesvirus 8 among injection drug users in San Francisco. J Infect Dis, 187: 974-981.
  3. . Bagni R, Whitby D. 2009. Kaposi’s sarcoma-associated herpesvirus transmission and primary infection. Curr Opin HIV AIDS, 4: 22-26.
  4. . Bernstein KT, Jacobson LP, Jenkins FJ, Vlahov D, Armenian HK. 2003. Factors associated with human herpesvirus type 8 infection in an injecting drug user cohort. Sex Transm Dis, 30: 199-204.
  5. . Biryahwaho B, Dollard SC, Pfeiffer RM, Shebl FM, Munuo S, Amin MM, Hladik W, Parsons R, Mbulaiteye SM. 2010. Sex and geographic patterns of human herpesvirus 8 infection in a nationally representative population-based sample in Uganda. J Infect Dis, 202: 1347-1353.
  6. . Butler LM, Dorsey G, Hladik W, Rosenthal PJ, Brander C, Neilands TB, Mbisa G, Whitby D, Kiepiela P, Mosam A, Mzolo S, Dollard SC, Martin JN. 2009. Kaposi sarcoma-associated herpesvirus (KSHV) seroprevalence in population-based samples of African children: evidence for at least 2 patterns of KSHV transmission. J Infect Dis, 200: 430-438.
  7. . Cannon MJ, Dollard SC, Smith DK, Klein RS, Schuman P, Rich JD, Vlahov D, Pellett PE. 2001. Blood-borne and sexual transmission of human herpesvirus 8 in women with or at risk for human immunodeficiency virus infection. N Engl J Med, 344: 637-643.
  8. . Chang Y, Cesarman E, Pessin MS, Lee F, Culpepper J, Knowles DM, Moore PS. 1994. Identification of herpesvirus-like DNA sequences in AIDS-associated Kaposi’s sarcoma. Science, 266: 1865-1869.
  9. . Diamond C, Thiede H, Perdue T, MacKellar D, Valleroy LA, Corey L. 2001. Seroepidemiology of human herpesvirus 8 among young men who have sex with men. Sex Transm Dis, 28: 176-183.
  10. . Gambus G, Bourboulia D, Esteve A, Lahoz R, Rodriguez C, Bolao F, Sirera G, Muga R, Del RJ, Boshoff C, Whitby D, Casabona J. 2001. Prevalence and distribution of HHV-8 in different subpopulations, with and without HIV infection, in Spain. AIDS, 15: 1167-1174.
  11. . Goedert JJ, Charurat M, Blattner WA, Hershow RC, Pitt J, Diaz C, Mofenson LM, Green K, Minkoff H, Paul ME, Thomas DL, Whitby D. 2003. Risk factors for Kaposi’s Sarcoma-associated herpesvirus infection among HIV-1-infected pregnant women in the USA. AIDS, 17: 425-433.
  12. . Greenblatt RM, Jacobson LP, Levine AM, Melnick S, Anastos K, Cohen M, DeHovitz J, Young MA, Burns D, Miotti P, Koelle DM. 2001. Human herpesvirus 8 infection and Kaposi’s sarcoma among human immunodeficiency virus-infected and -uninfected women. J Infect Dis, 183: 1130-1134.
  13. . Kakavand-Ghalehnoei R, Shoja Z, Najafi A, Mollahoseini MH, Shahmahmoodi S, Marashi SM, Nejati A, Jalilvand S. 2016. Prevalence of human herpesvirus-8 among HIV-infected patients, intravenous drug users and the general population in Iran. Sex Health, 13: 295-298.
  14. . Kedes DH, Operskalski E, Busch M, Kohn R, Flood J, Ganem D. 1996. The seroepidemiology of human herpesvirus 8 (Kaposi’s sarcoma-associated herpesvirus): distribution of infection in KS risk groups and evidence for sexual transmission. Nat Med, 2: 918-924.
  15. . Khajedaluee M, Babaei A, Vakili R, Valizade N, Homaei Shandiz F, Alavian SM, Seyed Nozadi M, Jazayeri SM, Hassannia T. 2016. Sero-Prevalence of Bloodborne Tumor Viruses (HCV, HBV, HTLV-I and KSHV Infections) and Related Risk Factors among Prisoners in Razavi Khorasan Province, Iran, in 2008. Hepat Mon, 16: e31541.
  16. . Larocca L, Leto D, Celesta BM, Maccarone S, Mazza C, Cacopardo B, Nigro L. 2005. Prevalence of antibodies to HHV-8 in the general population and in individuals at risk for sexually transmitted and blood-borne infections in Catania, Eastern Sicily. Infez Med, 13: 79-85.
  17. . Lee YM, Chuang SY, Wang SF, Lin YT, Chen YMA. 2014. Epidemiology of human herpesvirus type 8 and parvovirus B19 infections and their association with HIV-1 among men who have sex with men and injection drug users in Taiwan. J Microbiol Immunol Infect, 47: 233-238.
  18. . Liu Z, Fang Q, Zhou S, Minhas V, Wood C, He N, Zhang T. 2017a. Seroprevalence of Kaposi’s sarcoma-associated herpesvirus among HIV-infected Uygurs in Xinjiang, China. J Med Virol, 89: 1629-1635.
  19. . Liu Z, Fang Q, Zuo J, Wang J, Chen Y, Minhas V, Wood C, He N, Zhang T. 2017b. High seroprevalence of human herpesvirus 8 and herpes simplex virus 2 infections in men who have sex with men in Shanghai, China. J Med Virol, 89: 887-894.
  20. . Luo M-l, Tan H-z, Zhou Q, Wang S-y, Cai C, Guo Y-w, Shen L. 2013. Realizing the Meta-Analysis of Single Rate in R Software. EBM, 13: 181-184.
  21. . Minhas V, Wood C. 2014. Epidemiology and transmission of Kaposi’s sarcoma-associated herpesvirus. Viruses, 6: 4178-4194.
  22. . Moore PS. 2000. The emergence of Kaposi’s sarcoma-associated herpesvirus (human herpesvirus 8). N Engl J Med, 343: 1411-1413.
  23. . Parisi SG, Sarmati L, Pappagallo M, Mazzi R, Carolo G, Farchi F, Nicastri E, Concia E, Rezza G, Andreoni M. 2002. Prevalence trend and correlates of HHV-8 infection in HIV-infected patients. J Acquir Immune Defic Syndr, 29: 295-299.
  24. . Perna AM, Bonura F, Vitale F, Viviano E, Di Benedetto MA, Ajello F, Villafrate MR, Prestileo T, Mancuso S, Goedert JJ, Romano N. 2000. Antibodies to human herpes virus type 8 (HHV8) in general population and in individuals at risk for sexually transmitted diseases in Western Sicily. Int J Epidemiol, 29: 175-179.
  25. . Razonable RR. 2011. Rare, unusual, and less common virus infections after organ transplantation. Curr Opin Organ Transplant, 16: 580-587.
  26. . Renwick N, Halaby T, Weverling GJ, Dukers NHTM, Simpson GR, Coutinho RA, Lange JMA, Schulz TF, Goudsmit J. 1998. Seroconversion for human herpesvirus 8 during HIV infection is highly predictive of Kaposi’s sarcoma. AIDS, 12: 2481-2488.
  27. . Rezza G, Andreoni M, Dorrucci M, Pezzotti P, Monini P, Zerboni R, Salassa B, Colangeli V, Sarmati L, Nicastri E, Barbanera M, Pristera R, Aiuti F, Ortona L, Ensoli B. 1999. Human herpesvirus 8 seropositivity and risk of Kaposi’s sarcoma and other acquired immunodeficiency syndrome-related diseases. J Natl Cancer Inst, 91: 1468-1474.
  28. . Rezza G, Lennette ET, Giuliani M, Pezzotti P, Caprilli F, Monini P, Butto S, Lodi G, Di Carlo A, Levy JA, Ensoli B. 1998. Prevalence and determinants of anti-lytic and anti-latent antibodies to human herpesvirus-8 among Italian individuals at risk of sexually and parenterally transmitted infections. Int J Cancer, 77: 361-365.
  29. . Rohner E, Wyss N, Heg Z, Faralli Z, Mbulaiteye SM, Novak U, Zwahlen M, Egger M, Bohlius J. 2016. HIV and human herpesvirus 8 co-infection across the globe: Systematic review and meta-analysis. Int J Cancer, 138: 45-54.
  30. . Schwartz RA. 2004. Kaposi’s sarcoma: an update. J Surg Oncol, 87: 146-151.
  31. . Schwartz RA, Micali G, Nasca MR, Scuderi L. 2008. Kaposi sarcoma: a continuing conundrum. J Am Acad Dermatol, 59: 179-206.
  32. . Simpson GR, Schulz TF, Whitby D, Cook PM, Boshoff C, Rainbow L, Howard MR, Gao SJ, Bohenzky RA, Simmonds P, Lee C, De Ruiter A, Hatzakis A, Tedder RS, Weller IVD, Weiss RA, Moore PS. 1996. Prevalence of Kaposi’s sarcoma associated herpesvirus infection measured by antibodies to recombinant capsid protein and latent immunofluorescence antigen. Lancet, 349: 1133-1138.
  33. . Sosa C, Benetucci J, Hanna C, Sieczkowski L, Deluchi G, Canizal AM, Mantina H, Klaskala W, Baum M, Wood C. 2001. Human Herpes virus 8 can be transmitted through blood in drug addicts. Medicina, 61: 291-294.
  34. . Stiller CA, Trama A, Brewster DH, Verne J, Bouchardy C, Navarro C, Chirlaque MD, Marcos-Gragera R, Visser O, Serraino D, Weiderpass E, Dei Tos AP, Ascoli V. 2014. Descriptive epidemiology of Kaposi sarcoma in Europe. Report from the RARECARE project. Cancer Epidemiol, 38: 670-678.
  35. . Syvertsen JL, Agot K, Ohaga S, Strathdee SA, Camlin CS, Omanga E, Odonde P, Rota G, Akoth K, Peng J, Wagner KD. 2015. Evidence of injection drug use in Kisumu, Kenya: Implications for HIV prevention. Drug Alcohol Depend, 151: 262-266.
  36. . Tornesello ML, Biryahwaho B, Downing R, Hatzakis A, Alessi E, Cusini M, Ruocco V, Katongole-Mbidde E, Loquercio G, Buonaguro L, Buonaguro FM. 2010. Human herpesvirus type 8 variants circulating in Europe, Africa and North America in classic, endemic and epidemic Kaposi’s sarcoma lesions during pre-AIDS and AIDS era. Virology, 398: 280-289.
  37. . Vitale F, Viviano E, Perna AM, Bonura F, Mazzola G, Ajello F, Romano N. 2000. Serological and virological evidence of non-sexual transmission of human herpesvirus type 8 (HHV8). Epidemiol Infect, 125: 671-675.
  38. . Wang Y, Zhu B, Zhao X, Zhang X. 2000. Seroprevalence of Kaposi’s sarcoma associated herpesvirus infection among drug users. National Medical Journal of China, 80: 597-598.
  39. . Whitby D, Luppi M, Barozzi P, Boshoff C, Weiss RA, Torelli G. 1998. Human herpesvirus 8 seroprevalence in blood donors and lymphoma patients from different regions of Italy. J Natl Cancer Inst, 90: 395-397.
  40. . Yang PR, Tan XH, Guo SX, Yang L. 2010. Research of Kaposi’s Sarcoma-associated herpesvirus in drug users in one city of Xinjiang. Modern Preventive Medicine, 37: 107-109.
  41. . Zavitsanou A, Malliori M, Sypsa V, Petrodaskalaki M, Psichogiou M, Rokka C, Giannopoulos A, Kalapothaki V, Whitby D, Hatzakis A. 2010. Seroepidemiology of human herpesvirus 8 (HHV-8) infection in injecting drug users. Epidemiol Infect, 138: 403-408.
  42. . Zhang T, Liu Y, Zhang Y, Wang J, Minhas V, Wood C, He N. 2014a. Seroprevalence of human herpesvirus 8 and hepatitis C virus among drug users in Shanghai, China. Viruses, 6: 2519-2530.
  43. . Zhang T, Liu Z, Wang J, Minhas V, Wood C, Clifford GM, He N, Franceschi S. 2017. Seroprevalence of antibodies against Kaposi’s sarcoma-associated herpesvirus among HIV-negative people in China. Infect Agent Cancer, 12: 32.
  44. . Zhang T, Shao X, Chen Y, Zhang T, Minhas V, Wood C, He N. 2012. Human herpesvirus 8 seroprevalence, China. Emerg Infect Dis, 18: 150-152.
  45. . Zhang T, Wang L. 2017. Epidemiology of Kaposi’s sarcoma-associated herpesvirus in Asia: Challenges and opportunities. J Med Virol, 89: 563-570.
  46. . Zhang T, Yang Y, Yu F, Zhao Y, Lin F, Minhas V, Wood C, He N. 2014b. Kaposi’s sarcoma associated herpesvirus infection among female sex workers and general population women in Shanghai, China: a cross-sectional study. BMC Infect Dis, 14: 58.