Association between human immunodeficiency virus and herpes simplex virus type 2 seropositivity among male factory workers in Zimbabwe.
ABSTRACT To determine the seroprevalence of herpes simplex virus type 2 (HSV-2), to identify correlates of infection, and to describe the correlation with human immunodeficiency virus (HIV) seropositivity, 224 HIV-negative and 191 HIV-positive male factory workers in Zimbabwe were screened for HSV-2-specific antibodies. HSV-2 seroprevalence was 35.7% among HIV-negative subjects and 82.7% among HIV-positive subjects. The weighted estimate of HSV-2 seroprevalence in this population is 44.6%. The correlation between HIV and HSV-2 remained significant after controlling for multiple sex partners, paying for sex, and history of sexually transmitted disease (adjusted odds ratio, 8.0; 95% confidence interval, 4.8-13.1). If the association between HSV-2 and HIV is causal, then the high seroprevalence of HIV and HSV-2 suggests that suppressive HSV-2 treatment should be considered as a strategy to reduce HIV transmission in this population. HSV-2 seroconversion may be a suitable surrogate end point to evaluate HIV prevention interventions.
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ABSTRACT: Background: A number of surveys have reported a high prevalence of herpes simplex virus type 2 (HSV-2) infection in south central and east central Africa. Goal: To evaluate the distribution and modes of HSV-2 transmission in northern Cameroon. Study Design: A serosurvey was conducted among 194 adolescents and adults in a Cameroon hospital. Antibodies against HSV-2 were detected by a gG2-specific enzyme-linked immunoabsorbent assay. Results: The prevalence of HSV-2 antibodies was found to be 37.1%. In the multivariate analysis, female gender, no condom use, a positive syphilis serology, and HIV infection were significantly associated with HSV-2 infection. Conclusions: The current findings show that the HSV-2 seroprevalence in northern Cameroon is high and similar to that found in other African countries. HSV-2 infection represents a marker for at-risk sexual behavior and may be a common cofactor for HIV transmission in this geographic area.Sex Transm Dis 11/2001; 28(12):690-693. · 2.75 Impact Factor
- JAIDS Journal of Acquired Immune Deficiency Syndromes 01/2005; 39(3):333-339. · 4.39 Impact Factor
Association between Human Immunodeficiency Virus and Herpes Simplex Virus
Type 2 Seropositivity among Male Factory Workers in Zimbabwe
Lovemore Gwanzura, William McFarland,
D’Anna Alexander, Rae Lyn Burke,
and David Katzenstein
Department of Medical Laboratory Technology, University of
Zimbabwe, Harare; Center for AIDS Prevention Studies, University of
California, San Francisco, Chiron Corporation, Emeryville, and
Department of Infectious Diseases and Geographic Medicine, Stanford
University, Stanford, California
To determine the seroprevalence of herpes simplex virus type 2 (HSV-2), to identify correlates of
infection, and to describe the correlation with human immunodeficiency virus (HIV) seropositivity,
224 HIV-negative and 191 HIV-positive male factory workers in Zimbabwe were screened for HSV-
2–specific antibodies. HSV-2 seroprevalence was 35.7% among HIV-negative subjects and 82.7%
among HIV-positive subjects. The weighted estimate of HSV-2 seroprevalence in this population is
44.6%. The correlation between HIV and HSV-2 remained significant after controlling for multiple
sex partners, paying for sex, and history of sexually transmitted disease (adjusted odds ratio, 8.0;
95% confidence interval, 4.8–13.1). If the association between HSV-2 and HIV is causal, then the
high seroprevalence of HIV and HSV-2 suggests that suppressive HSV-2 treatment should be
considered as a strategy to reduce HIV transmission in this population. HSV-2 seroconversion may
be a suitable surrogate end point to evaluate HIV prevention interventions.
Epidemiologic and biologic evidence increasingly impli-
cate sexually transmitted diseases (STDs) as causal factors
in human immunodeficiency virus (HIV) transmission .
The relatively high prevalence of untreated STDs in sub-
Saharan Africa has been proposed as a contributing factor in
the higher prevalence of heterosexually transmitted HIV in
that region compared with the industrialized world . The
hypothesis is supported by the success of an HIV prevention
intervention based on community-wide enhanced STD treat-
ment in Mwanza, Tanzania .
STDs that cause genital ulceration, such as syphilis, chan-
croid, and herpes simplex virus type 2 (HSV-2) infection, are
particularly implicated in facilitating HIV transmission [1, 4].
Genital ulcer disease (GUD) is believed to increase the risk of
HIV acquisition per sexual exposure by increasing the amount
of HIV shedding through genital lesions and by providing an
easy portal of entry of the virus into the host .
Although GUD is a common complaint at STD clinics in
Africa, screening for HSV-2 is rarely done. Nonetheless, recent
studies confirm that HSV-2 is common in adult populations on
the continent. Laboratory evidence of HSV-2 was present
among 36% of GUD patients in Kampala . In one study that
screened stored sera from Dakar, HSV-2 seroprevalence ranged
from 20% of surgical patients to as high as 96% among prosti-
tutes . Considering the high prevalence of HSV-2, the in-
creased shedding of HIV through genital herpes lesions, and
the fact that persons with HSV-2 remain potentially infectious
for life, HSV-2 may account for a large proportion of HIV
infection in Africa.
To determine the prevalence of HSV in a population of
male factory workers in Harare, Zimbabwe, we screened stored
serum specimens from subjects participating in an HIV preven-
tion intervention for HSV-1– and HSV-2–specific antibodies.
The availability of HIV serostatus at enrollment in the interven-
tion as well as demographic and sexual risk–related data per-
mitted examination of the correlation between HIV and HSV-
2 seropositivity in case-control analysis.
Received 15 May 1997; revised 2 September 1997.
Presented in part: International Union of Immunologic Sciences Meeting,
Capetown, South Africa, 9–14 March 1997.
The study was carried out as part of HIVNET 011, for which written in-
formed consent was obtained from all participants. Human experimentation
guidelines of the US Department of Health and Human Services, the National
Commission for the Protection of Human Subjects of Biomedical and Behav-
ioral Research,Stanford University MedicalCenter InstitutionalReview Board,
and the Medical Research Council of Zimbabwe were followed.
D.A.A. and R.L.B. are employees of Chiron Corporation.
Financial support: NIH (AI-33868); Preparation for AIDS Vaccine Evalua-
tion (PAVE); and HIVNET 011. HSV1/2 assays were provided by Chiron.
Reprints or correspondence: Dr. William McFarland, Seroepidemiology
Unit, AIDS Office, San Francisco Dept. of Public Health, 25 Van Ness Ave.,
Suite 500, San Francisco, CA 94102-6033 (Willi_McFarland@dph.sf.ca.us).
HSV-1–specific antibodies originated from subjects enrolled in the
Zimbabwe AIDS Prevention Project, a longitudinal cohort study
established to determine the prevalence, incidence, and correlates
of HIV infection and to evaluate a peer education intervention.
Recruitment and follow-up methods and observational findings of
the cohort have been described in detail elsewhere [8, 9]. Briefly,
subjects are male factory workers recruited and followed at 40
work sites in greater Harare, Zimbabwe. At enrollment and at
6-month intervals, subjects are interviewed on HIV risk–related
behaviors, and blood is drawn for serologic testing for HIV, syphi-
Serum specimens screened for HSV-2– and
The Journal of Infectious Diseases
? 1998 by The University of Chicago. All rights reserved.
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482Concise Communications JID 1998;177 (February)
lis, and hepatitis B. An aliquot of serum is stored. As of May
1997, ú3000 subjects have been enrolled. Nineteen percent of
subjects are HIV-positive at enrollment. HIV seroincidence in the
cohort is Ç3/100 person-years; the incidence of reported STD
syndromes is 10/100 person-years.
To assess the correlation between HIV and
HSV-2 seropositivity, a case-control study without matching was
used. A pre-study sample size calculation estimated that 200 cases
and 200 controls would provide ample power to detect an associa-
tion between the presence of HIV and HSV-2 antibodies. Stored
serum specimens were consecutively retrieved starting from the
first date of enrollment until the sample size was approximated
for both HIV-negative and HIV-positive subjects. Although not
random, the consecutive sampling method was likely to produce
a representative sample of cases and controls, as no differences
were observed among subjects recruited early or late in the study.
Because of the size of the storage boxes and the number of tests
that could be run per kit, 224 HIV-negative and 191 HIV-positive
subjects were ultimately screened for HSV-1 and HSV-2 antibod-
ies. HIV serostatus and risk-related information for the correspond-
ing subjects were recorded at the time of enrollment.
A strip recombinant immunoblot assay
(RIBA HSV Type 1/Type 2 SIA; Chiron, Emeryville, CA) was
used to detect and differentiate HSV-1– and HSV-2–specific anti-
bodies. The RIBA type 1/type 2 nitrocellulose strips include re-
combinant antigen bands from HSV-1 (gG1 and gB1) and HSV-
2 (gG2 and gD2) as well as controls for IgG. Antibodies specific
for HSV-1 will react with gB1 and gG1 antigen bands but not
with the gG2 band. HSV-2 antibodies will react with gG2 and
gD2 bands but not with gB1 and gG1 bands. Because of homology
between HSV-1 and HSV-2 in the gD glycoprotein, reactivity is
expected for both viral types to the gD2 band. Compared with
Western blot, the sensitivity of the RIBA assay is 95.1% for HSV-
1 and 98.2% for HSV-2; specificity compared with Western blot
is 99.4% for both HSV-1 and HSV-2 .
The presence of HIV antibodies was demonstrated by use of
a third-generation EIA (HIV-1/HIV-2; Abbott, Abbott Park, IL).
Specimens reactive or indeterminate in the Abbott EIA were re-
tested with a second, third-generation EIA (Enzygnost Anti-HIV
1/2 Plus; Behring, Marburg, Germany). Samples were considered
HIV antibody–positive when positive results were obtained from
both EIAs. Indeterminate or conflicting results were resolved by
Western blot (HIV Blot 2.2; Diagnostic Biotechnology, Singa-
We first examined associations between
HSV-2 seropositivity and variables previously shown to be related
to HIV infection in the study population . These variables in-
cluded age, education, marital status, history of STD, history of
paying for sex, and number of sex partners. At baseline, subjects
were asked risk information pertaining to the year prior to the
interview. In the present analysis, associations between baseline
serology and reported risk behaviors in the preceding year were
examined. No information on previous HIV testing and knowledge
of serostatus was collected. Bivariate associations were assessed
by the x2test for trend or test for differences in proportions.
For these analyses, HIV-negative and HIV-positive subjects were
examined separately. HIV-positive subjects were then compared
with HIV-negative subjects with respect to HSV-2 serostatus by
use of logistic regression analysis. To control for the potential
tory workers in Harare, Zimbabwe.
Prevalence of HSV-2–specific antibodies among male fac-
(n Å 224)
(n Å 191)Variable
Age group, years
Secondary school or more
Less than secondary school
Married, live together
Married, live apart
History of any STD, last year
History of genital ulcer, last
History of paying for sex,
Number of sex partners, last
80 (35.7)158 (82.7)
tum (%). STD, sexually transmitted disease.
* x2test for trend: P õ .001.
†x2test for difference in proportions: P õ .001.
‡x2test for difference in proportions: P õ .01.
Data are no. of subjects testing HSV-2–seropositive for each stra-
confounding effect of high-risk sexual behaviors that could result
in both HSV-2 and HIV infection, we included history of STD,
paying for sex, and multiple sex partners in a multiple logistic
The prevalence of HSV-2–specific antibodies was 35.7%
among HIV-negative subjects and 82.7% among HIV-positive
subjects. Given that 19% of all subjects at the factories are
HIV-positive at enrollment , a weighted estimate of the
prevalence of HSV-2 in this male population is 44.6%. With
theexception ofa singlespecimen fromanHSV-2–positive but
HIV-negative subject, all participants were HSV-1–positive.
Among HIV-negative subjects (table 1), demographic char-
acteristics significantly associated with HSV-2 seropositivity
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483JID 1998;177 (February)Concise Communications
male factory workers in Harare, Zimbabwe.
Association between antibodies to HIV and HSV-2 among
The body of evidence from other studies weighs in favor of
a causal relationship between HIV and HSV-2 [1, 3–5] by
meeting key criteria for causation in observational studies as
reasoned by Hill (cited in ): biologic plausibility, the cor-
rect temporal sequence, the strength of association, and consis-
tency across different studies. In the present study, HSV-2
seropositivity was overwhelmingly the strongest correlate of
HIV seropositivity, with an adjusted odds ratio of 8.0. HSV-2
seropositivity had a greater magnitude of association with HIV
than did any other variable examined in the present study or in
our previous analysis of risk factors for prevalent HIV infection
among 2691 cohort participants .
Several limitations of the present study are recognized. The
case-control design does not permit assessment of a causal
association between HSV-2 infection and HIV acquisition. In
particular, the temporal sequence or directionality of the associ-
ation betweenHSV-2 andHIV couldnot be analyzed.Although
the association was not confounded by the most common be-
havioral risk factors for HIV infection in the study population
(multiple partners,history ofSTD, paying forsex), itis possible
that unmeasured behavioral risk factors common to both HSV-
2 and HIV infection could cause residual confounding. More-
over, the role of asymptomatic or subclinical HSV-2 infection
on facilitating HIV transmission remains to be assessed, partic-
ularly in view of the fact that very few subjects with antibodies
to HSV-2 in the present study reported history of GUD within
the preceding year. In another study, only 21% of STD clinic
attendeeswith serologicevidence ofHSV-2 reportedsymptoms
or histories of genital herpes .
Despite these limitations, the association between HSV-2
and HIV infection has several potential practical applications.
The findings support the use of HSV-2 as a serologic end point
in the assessment of HIV prevention interventions that seek to
reduce high-risk sexual behaviors. The presence or acquisition
of antibodies to HSV-2 is a promising, objective measure of
high-risk sexualbehavior [13,14]. HSV-2seropositivity among
HIV-negative subjects may be useful in identifying a subpopu-
lation of persons at high risk of acquiring HIV. Prevention
resources and recruitment for prevention intervention studies
may be targeted to such persons. If the relationship between
HSV-2 infection and HIV acquisition is indeed causal, then
suppressive treatment of HSV-2 has biologic plausibility as an
HIV prevention intervention. Suppression of HSV-2 among
HIV-positive persons may be particularly important in pre-
venting secondary transmission.
Model: outcome HIV antibody–
History of STD last year
History of paying for sex last year
§2 sex partners last year
* Odds ratios adjusted for other variables in model.
STD, sexually transmitted disease.
included older age, lower education level, and marital status.
Being married but living apart from one’s wife was associated
with a higher prevalence of HSV-2 (54.1%) compared with
being single (10.9%) or being married and residing with one’s
wife (41.2%). History of genital ulcer in the last year was
significantly associated with HSV-2 seropositivity. A nonsig-
nificant increase in HSV-2 seropositivity (34.6% vs. 50.0%, P
Å .20) was noted among subjects with a history of any STD in
the last year (mostly urethral discharge). HIV-negative subjects
reporting one or more sex partners in the last year were more
likely to be HSV-2 seropositive than were those reporting no
sex partners in the last year; however, no linear trend for in-
creasing HSV-2 seroprevalence with increasing number of sex
partners was found (P Å .81). History of paying for sex in the
last year was not associated with HSV-2 serostatus (P Å .86).
No demographic or behavioral variables were significantly
associated with HSV-2 seropositivity among HIV-positive sub-
jects (table 1). The association between HSV-2 and marital
status was borderline significant (P Å .053) among HIV-posi-
In case-control analysis (table 2), HSV-2 seropositivity was
strongly associated with HIV seropositivity. The relationship
remained significant after controlling for other risk factors for
HIV infection, including history of STD, history of paying for
sex, and two or more sex partners in the last year (adjusted
odds ratio, 8.0; 95% confidence interval, 4.8–13.1).
The estimated prevalence of HSV-2–specific antibodies in
our study population, 44.6%, was high but comparable with
that in other populations in the region. The prevalence of HSV-
2 antibodies was 40.8% among adults in Kinshasa and 51.3%
among hospital workers in Rwanda . The higher prevalence
of HSV-2 among older subjects, subjects with a lower level of
education, and those with one or more sex partners is consistent
with the known epidemiology of the virus .
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Identification and Characterization of Herpes Simplex Virus–Specific CD4/T
Cells in Corneas of Herpetic Stromal Keratitis Patients
Georges M. G. M. Verjans, Lies Remeijer,
Robert S. van Binnendijk, Jose ´ G. C. Cornelissen,
Hennie J. Vo ¨lker-Dieben, Seerp G. Baarsma,
and Albert D. M. E. Osterhaus
Rotterdam Eye Hospital, and Institute of Virology, Erasmus University
Rotterdam, and Free University Hospital, Amsterdam, The Netherlands
Herpetic stromal keratitis (HSK) is a corneal disease initiated by a herpes simplex virus (HSV)
infection with a postulated T cell–mediated immunopathology. To study the antigen specificity of
cornea-infiltrating T cells in HSK patients, T cells were isolated and expanded by mitogenic stimulation
fromcorneasof2patients with HSV-1–mediatedHSK.Asubstantial number oftheTcell clones(TCCs)
obtained from these T cell lines were HSV-specific. All HSV-specific TCCs were of the CD3/CD4/CD80
phenotype. These TCCs responded to autologous HSV-infected corneal keratocytes, which expressed
HLA classII molecules following incubationwith interferon-g. Upon HSV-specific stimulation,all TCCs
secreted interleukin-4, interleukin-5, and interferon-g. The data presented suggest that HSV-specific
CD4/T cells play a role in the immunopathogenesis of HSK in humans and that corneal keratocytes
may act as antigen-presenting cells in this local T cell response.
Recurrent herpes simplex virus (HSV) infections of the cor-
nea can lead to tissue-destructive inflammation of the corneal
stroma. This disease, known as herpetic stromal keratitis
(HSK), is a leading infectiouscause of corneal blindness world-
wide. The stromal pathology seen in HSK patients is most
probably not due to the direct cytopathic effect of the virus
but more likely the result of a local cellular immune response
(reviewed in ). Studies in the mouse model of HSK have
shown that CD4/T cells, possibly HSV-specific, that secrete
type 1 cytokines (i.e., Th1 cells) play a pivotal role in the
immunopathology of this disease [1–4].
Studies on T cell involvement in the immunopathogenesis
of HSK in humans is limited to immunohistologic analyses
and phenotypic characterization of isolated intracorneal T cells
[5, 6]. In the present study, a protocol was developed that
enabled the expansion and functional characterization of intra-
corneal T cells obtained from 2 HSK patients.
Received 24 March 1997; revised 8 September 1997.
Presented in part: 4th International Symposium on Ocular Inflammation,
London, September 1996.
The study protocol was approved by the local investigational review board,
and informed consent was obtained from all patients included in this study.
Financial support: ‘‘De Rotterdamse Vereniging Blinden Belangen,’’
‘‘Stichting HOF,’’ ‘‘Hoornvlies Stichting,’’ and the ‘‘Flieringa-Houet Sticht-
ing’’ (G.M.G.M.V. and J.G.C.C.). R.S.v.B. was supported by the United Na-
tions Development Programme, World Health Organization (V21/181/35/ID
91/RV0020), and NIH (AI-93-06; AI-35144).
Reprints or correspondence: Dr. G. M. G. M. Verjans, Institute of Virology,
Erasmus University Rotterdam, PO Box 1738, 3000 DR, Rotterdam, The Neth-
Materials and Methods
The Journal of Infectious Diseases
? 1998 by The University of Chicago. All rights reserved.
Clinical material and reagents.
blood mononuclear cells (PBMC) were obtained from 2 patients,
Cornealbuttons and peripheral
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