Séverin-Guy Mahiane
email: mahianes@yahoo.fr

Camille Legeai
email: camille.legeai@apr.aphp.fr

Dirk Taljaard

Aurélien Latouche
email: aurelien.latouche@uvsq.fr

Adrian Puren
email: adrianp@nicd.ac.za

Aurélie Peillon
email: aureliepeillon@aol.com

Jean Bretagnolle

Pascale Lissouba
email: pascale.lissouba@inserm.fr

Eugène-Patrice Ndong Nguéma

Elisabeth Gassiat
email: elisabeth.gassiat@math.u-psud.fr

Prof. Bertran Auvert

Transmission probabilities of HIV and herpes simplex virus type 2, effect of male circumcision and interaction: a longitudinal study in a township of South Africa

Keywords: HSV-2, HIV, male circumcision, mathematical modeling, heterosexual transmission

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Introduction

Observational studies have suggested an association between HIV and herpes simplex virus type 2 (HSV-2) [START_REF] Corey | The effects of herpes simplex virus-2 on HIV-1 acquisition and transmission: a review of two overlapping epidemics[END_REF][START_REF] Wald | Risk of human immunodeficiency virus infection in herpes simplex virus type 2-seropositive persons: a meta-analysis[END_REF][START_REF] Freeman | Herpes simplex virus 2 infection increases HIV acquisition in men and women: systematic review and meta-analysis of longitudinal studies[END_REF][START_REF] Brown | and prevalent herpes simplex virus type 2 infection increases risk of HIV acquisition among women in Uganda and Zimbabwe[END_REF]. However our knowledge is limited regarding their interaction. Determining a) the transmission probabilities of HSV-2 and HIV, b) the cofactor effect of each virus on the transmission probability of the other and c) the cofactor effect of male circumcision (MC) status on these transmission probabilities will help understand the dynamics of the HSV-2 and HIV epidemics in Africa and develop targeted interventions.

Published values of female-to-male HSV-2 transmission probability per sex-act were obtained from studies investigating discordant couples, mostly from developed countries. The value of 0.00015 was found by a study conducted in the United States [START_REF] Wald | Effect of condoms on reducing the transmission of herpes simplex virus type 2 from men to women[END_REF]. Another study conducted in 96 sites from the United States, Canada, Europe, Latin America and Australia found a value of 0.00035 [START_REF] Corey | Once-daily valacyclovir to reduce the risk of transmission of genital herpes[END_REF].

Epidemiologic studies have also estimated the probability of female-to-male HIV-1 transmission per sex-act. A study conducted in Rakai (Uganda) estimated this probability to be 0.0011 (95% confidence interval, CI: 0.0008-0.0015) [START_REF] Gray | Probability of HIV-1 transmission per coital act in monogamous, heterosexual, HIV-1-discordant couples in Rakai, Uganda[END_REF]. However, studies in Kenya and in Thailand, investigating sexual encounters with prostitutes, evaluated per-contact HIV-1 transmission probabilities to be around 30 to 80 times higher than the Ugandan study [START_REF] Mastro | Probability of female-to-male transmission of HIV-1 in Thailand[END_REF][START_REF] Cameron | Female to male transmission of immunodeficiency virus type 1: risk factors for seroconversion in men[END_REF]. In the context of multiple partnerships, a Kenyan prospective cohort study estimated the overall probability of female-to-male HIV-1 transmission per sex-act at 0.0063 (95% CI: 0.0035-0.0091) [START_REF] Baeten | Female-to-male infectivity of HIV-1 among circumcised and uncircumcised Kenyan men[END_REF]. Recently, a systematic review estimated that the crude female-to-male transmission probability per-sex-act for developing countries was 0.0030 (95% CI: 0.0009-0.010) [START_REF] Boily | The risk of HIV-1 infection per sexual contact in absence of antiretroviral therapy: a systematic review and metaanalysis of observational studies[END_REF].

A synergy between HIV and HSV-2 has been observed. Epidemiologic studies have demonstrated that prevalent HSV-2 is associated with a 2-to 4-fold increased risk of HIV-1 acquisition [START_REF] Corey | The effects of herpes simplex virus-2 on HIV-1 acquisition and transmission: a review of two overlapping epidemics[END_REF][START_REF] Wald | Risk of human immunodeficiency virus infection in herpes simplex virus type 2-seropositive persons: a meta-analysis[END_REF][START_REF] Freeman | Herpes simplex virus 2 infection increases HIV acquisition in men and women: systematic review and meta-analysis of longitudinal studies[END_REF][START_REF] Brown | and prevalent herpes simplex virus type 2 infection increases risk of HIV acquisition among women in Uganda and Zimbabwe[END_REF][START_REF] Weiss | The epidemiology of HSV-2 infection and its association with HIV infection in four urban African populations[END_REF]. Several mechanisms can explain this association. The presence of other sexually transmitted infections (STIs) could enhance HIV susceptibility by breaching the epithelial barrier, recruiting HIV target cells to the genital tract, or generating a proinflammatory local immune milieu [START_REF] Kaul | The genital tract immune milieu: An important determinant of HIV susceptibility and secondary transmission[END_REF]. This has been confirmed by one study which estimated the effect of genital ulceration associated with HSV-2 infection on HIV transmission probability among HIV-1 serodiscordant couples. This study found that genital ulceration in the previous 10 months was a risk factor for HIV transmission, with per-contact risk increasing 5-fold (0.0062 vs. 0.0012) [START_REF] Corey | The effects of herpes simplex virus-2 on HIV-1 acquisition and transmission: a review of two overlapping epidemics[END_REF].

In terms of co-infections, both clinical and sub-clinical reactivations of HSV-2 are associated with the influx of activated CD4+ T cells into the genital mucosa and skin, and conversely several HSV-2 proteins are capable of reactivating a latent HIV infection [START_REF] Corey | copathogens--HIV-1 and HSV-2[END_REF]. These interactions appear to account for the higher titers of HIV-1 in the plasma of coinfected patients: HIV-1 is shed from genital ulcers caused by HSV-2 and viral variants of HIV-1 that arise from these ulcers can appear and persist in plasma [START_REF] Schacker | Frequency of symptomatic and asymptomatic herpes simplex virus type 2 reactivations among human immunodeficiency virus-infected men[END_REF]. Frequent sub-clinical episodes of HSV-2 reactivation are associated with both a higher frequency and a higher amount of HIV-1 in genital secretions [START_REF] Nagot | Reduction of HIV-1 RNA levels with therapy to suppress herpes simplex virus[END_REF]. Hence, since genital co-infections increase HIV levels in the genital secretions, they may be an important factor in secondary sexual transmission [START_REF] Kaul | The genital tract immune milieu: An important determinant of HIV susceptibility and secondary transmission[END_REF].

HIV infection is also thought to facilitate HSV-2 transmission. Outbreaks of HSV-2 are generally more severe, extensive, persistent, and invasive for those with more advanced HIV disease [START_REF] Schacker | Frequency of symptomatic and asymptomatic herpes simplex virus type 2 reactivations among human immunodeficiency virus-infected men[END_REF][START_REF] Augenbraun | Increased genital shedding of herpes simplex virus type 2 in HIV-seropositive women[END_REF]. In fact, persistent HSV-2 infection was one of the original opportunistic infections that resulted in the identification of AIDS [START_REF] Siegal | Severe acquired immunodeficiency in male homosexuals, manifested by chronic perianal ulcerative herpes simplex lesions[END_REF]. Three randomized controlled trials demonstrated that MC reduces the female-to-male sexual acquisition of HIV by about 60% [START_REF] Auvert | Randomized, controlled intervention trial of male circumcision reduction of HIV infection risk: the ANRS 1265 Trial[END_REF][START_REF] Gray | Male circumcision for HIV prevention in men in Rakai, Uganda: a randomised trial[END_REF][START_REF] Bailey | Male circumcision for HIV prevention in young men in Kisumu, Kenya: a randomised controlled trial[END_REF]. A meta-analysis of observational data showed that the risk reduction of HSV-2 infection by MC was of borderline statistical significance (RR=0.88, 95% CI: 0.77-1.01) [START_REF] Weiss | Male circumcision and risk of syphilis, chancroid, and genital herpes: a systematic review and meta-analysis[END_REF]. Preliminary results of the effect of MC on male HSV-2 acquisition that were observed in the Rakai and Orange Farm (South Africa) MC trials were presented in international AIDS conferences [START_REF] Auvert | Can male circumcision prevent acquisition of HSV-2 infection? 16th Biennial Meeting of the International Society for Sexually Transmitted Diseases Research[END_REF][START_REF] Tobian | Trial of Male Circumcision: Prevention of HSV-2 in Men and Vaginal Infections in Female Partners, Rakai, Uganda[END_REF]. The study's first objective was to estimate the per-sex-act and per-partnership femaleto-male transmission probabilities (FtoMTPs) of HSV-2 and HIV. The second objective was to assess the effect of each virus on the FtoMTP of the other. The last objective was to assess the effect of MC on these FtoMTPs. This analysis was conducted using a specific mathematical modeling applied to the longitudinal data of the MC trial conducted in Orange Farm among men aged 18-24 [START_REF] Auvert | Randomized, controlled intervention trial of male circumcision reduction of HIV infection risk: the ANRS 1265 Trial[END_REF]. Orange Farm is a township located close to Johannesburg in Gauteng province, an area with a high HIV prevalence [START_REF]Report National HIV and Syphilis Prevalence Survey South Africa 2006[END_REF]. Samples collected during this trial were specifically tested for HSV-2. The results of a cross-sectional study conducted in the same township [START_REF] Auvert | Can Highly Active Antiretroviral Therapy Reduce the Spread of HIV?: A Study in a Township of South Africa[END_REF] were used to estimate the HIV and HSV-2 statuses of each female partner of the males having participated in the MC trial.

Methods

Collection of data

The technical details of the trial have been published elsewhere [START_REF] Auvert | Randomized, controlled intervention trial of male circumcision reduction of HIV infection risk: the ANRS 1265 Trial[END_REF] and only a summary will be presented in this article. Between February 2002 and July 2004, 3274 uncircumcised males, aged 18 to 24, were recruited, randomized into two groups and followed up. At baseline, HSV-2 and HIV serological statuses were ascertained and MC was offered to the intervention group. During each of the follow-up visits at 3, 12 and 21 months, MC status was assessed by a nurse through genital examination and a blood sample was taken and tested for HIV and HSV-2. Information about sexual behavior was collected, including number of partners as a function of time, number of sexual contacts with each partner, reported condom use with each partner and age of each partner. The dataset used in this study included 590 additional 21-month follow-up visits (20.0% of the total number of 21-month visits) which were not included when the analysis of the effect of MC on HIV acquisition was published because corresponding laboratory data were not available at that time.

Laboratory methods

Details of the HIV testing methods have been described in the main publication of the trial [START_REF] Auvert | Randomized, controlled intervention trial of male circumcision reduction of HIV infection risk: the ANRS 1265 Trial[END_REF]. Plasma samples were tested using an HSV type 2 specific IgG assay to detect HSV-2 antibodies (Kalon HSV-2 gG2 assay; Kalon Biologicals Ltd., Aldershot, UK), according to the manufacturer's recommendations.

Data analysis

We constructed two mathematical models of HIV and HSV-2 statuses as functions of time. These models were used to estimate the FtoMTPs of HIV and HSV-2. In this article, FtoMTP is defined as the probability that a susceptible male becomes infected following a sex act or partnership with an infected female. These mathematical models considered HIV and HSV-2 statuses simultaneously. Model 1 estimated the per-sex-act FtoMTPs of HIV and HSV-2, and model 2 their per-partnership FtoMTPs. These FtoMTPs were supposed to be constant as a function of time and were estimated by fitting the HIV and HSV-2 statuses predicted by the models on the observed data using the maximum likelihood method. Each of these models took into account three types of dichotomous cofactors: the effect of each virus on the FtoMTP of the other (2 cofactors), the effect of MC on the FtoMTP of each virus (2 cofactors) and the effect of reported condom use on each of these FtoMTPs (2 cofactors).

Condom use was dichotomized as follows: a given partnership was considered protected when condom use was reported as "always" used for the partnership. Otherwise the partnership was considered not protected. All sexual contacts of a protected partnership were considered as protected, otherwise they were considered as not protected.

The model estimated the HIV and HSV-2 statuses of each female partner of the males. For this estimation, we used data from a representative sample of 476 females aged 15-49 years. These data had been collected during a cross-sectional survey conducted in the same community in the year 2004 [START_REF] Auvert | Can Highly Active Antiretroviral Therapy Reduce the Spread of HIV?: A Study in a Township of South Africa[END_REF]. They included age, HIV serostatus, HSV-2 serostatus obtained with the same HSV-2 assay and reported number of sexual partners in the past 12 months. HIV and HSV-2 prevalences were 25.8% and 67.7%, respectively. 24.0% of women were co-infected by the two viruses. The mean (median) number of lifetime partners was 3.4 (3). For each female partner of each male of the MC trial, we estimated the probability of being infected with HIV and/or HSV-2. This estimation was done using the age of these partners and the distribution of the HIV and HSV-2 statuses of women as a function of age and of their reported number of sexual partners. In this manner, the more sexual partners a female had had in the past 12 months the more likely she was to be a partner of males (see Annex 1 in supporting document).

The effect of each cofactor was expressed by its relative risk (RR). The RR of any cofactor was obtained by dividing the FtoMTP in the presence of the cofactor by the FtoMTP in the absence of the cofactor. This method was applied to estimate the effect of MC and the effect of reported condom use on the FtoMTPs of HIV and HSV-2. To estimate the effect of HSV-2 infection on the FtoMTP of HIV, we considered that this FtoMTP was multiplied by the corresponding RR when only one of the partners was infected by HSV-2 and that it was multiplied by RR 2 when both partners were infected. The same method was applied to estimate the effect of HIV on the FtoMTP of HSV-2. We assumed that the effects of the cofactors were constant as a function of time.

Details of the model are given in Annex 1 (see supporting document). Regarding the FtoMTP of HIV per sex act, when all the cofactors were constant (reported condom use, MC status, HSV-2 status of partners), the model assumed that the FtoMTP of HIV after n sexual contacts (P n,HIV ) was given by the following formula:

n HIV HIV n, ) P (1 1 P - - = .
In this formula, P HIV is the FtoMTP of HIV per sex act. The formulas for HSV-2 and for the FtoMTPs per partnership are similar. The FtoMTPs of HIV and HSV-2 as well as the six RRs were estimated in a unique simulation of model 1 for the per-sex-act FtoMTPs and of model 2 for the per-partnership FtoMTPs.

A first complementary set of analyses was performed to estimate the FtoMTPs of HIV and HSV-2 with only MC status as cofactor. It generated the FtoMTP of each infection averaged on reported condom use and on the other infection. A second complementary set of analyses was conducted to allow the comparison of the results obtained by this modeling approach with those obtained by a published survival analysis performed on the same dataset [START_REF] Auvert | Randomized, controlled intervention trial of male circumcision reduction of HIV infection risk: the ANRS 1265 Trial[END_REF]. For this, we estimated the intention-to-treat (ITT) RR of MC on the FtoMTP of HIV by replacing circumcision status by the randomization group in the model's equations with only MC as cofactor. These analyses were then repeated with HSV-2 in order to obtain the ITT RR of MC on the FtoMTP of HSV-2.

To estimate the 95% CI of the FtoMTPs and RRs, we used the bootstrap re-sampling method with 2000 replications [START_REF] Carpenter | Bootstrap confidence intervals: when, which, what? A practical guide for medical statisticians[END_REF]. For each bootstrap simulation, new samples of 3274 males and 476 females were randomly selected from the MC trial data for males and from the cross-sectional survey data for females. The 95% CI were estimated by the interval between the 2.5 th and 97.5 th percentiles of the bootstrapped simulations. The RRs were statistically compared with 1 by estimating a corresponding two-tailed P-value. This P-value was determined using the percentile (r) corresponding to a RR of 1 by P=2r/100 when r≤50 and by P=2(100-r)/100 when r≥50. When the value 1 was out of the range given by the re-sampling method, we used P<0.001 (2x1/2000).

Simulations and estimations were performed using the R programming language (version 2.6.1) [START_REF] Team | R: A language and environment for statistical computing[END_REF]. R scripts can be provided upon request to the corresponding author.

Results

The HSV-2 and HIV prevalences at enrolment were 5.9% (194/3274) and 4.4% (145/3274), respectively. Table 1 presents the number of new HSV-2 infections, new HIV infections, and new HSV-2/HIV co-infections observed at the end of each follow-up visit.

The per-sex-act FtoMTPs of HIV and HSV-2, for an uncircumcised and non-condom user male, in the absence of the other virus in both partners, were 0.0047 (95% CI: 0.0014-0.017) and 0.0067 (95% CI: 0.0028-0.014), respectively. The corresponding per-partnership FtoMTPs were 0.017 (95% CI: 0.0065-0.044) and 0.026 (95% CI: 0.014-0.047), respectively. For each virus, the per-partnership FtoMTP was about 4 times higher than the corresponding per-sex-act FtoMTP.

Table 2 gives the multivariate RRs of the FtoMTPs of HIV per sex act and per partnership. The effects of MC and of an HSV-2 infection in either partner were similar in both cases: MC significantly reduced the FtoMTPs of HIV whereas HSV-2 infection in either partner significantly increased the FtoMTPs of HIV. Reported condom use significantly reduced the per-partnership FtoMTP of HIV and the confidence interval of the effect of reported condom use on the per-sex-act FtoMTP was large. Table 3 gives the multivariate RRs of the FtoMTPs of HSV-2 per sex act and per partnership. The results obtained were qualitatively similar to the results obtained with HIV but quantitatively weaker.

In this longitudinal study, 50.5% of males were circumcised at the beginning of the follow-up. Table 4 presents the FtoMTPs of HIV and HSV-2 per sex act and per partnership as functions of MC status, and averaged on the other cofactors. The univariate protective effect of MC status is significant for HIV and HSV-2. The protective effect on HIV is about twice the protective effect on HSV-2. The per-sex-act and per-partnership FtoMTPs of HIV, averaged on MC, reported condom use and HSV-2 status, were 0.0088 (95% CI: 0.0061-0.013) and 0.032 (95% CI: 0.022-0.045), respectively. The corresponding values for HSV-2 were close: 0.0099 (95% CI: 0.0074-0.013) and 0.037 (95% CI: 0.028-0.048), respectively.

In the univariate ITT analysis, the effects of MC on per-sex-act and per-partnership FtoMTPs of HIV were 0.37 (95% CI: 0.19-0.71, P=0.004) and 0.40 (95% CI: 0.21-0.73, P=0.004), respectively. The corresponding values for HSV-2 showed a non-significant protective effect with RR values of 0.79 (95% CI: 0.50-1.2, P=0.32) and 0.83 (95% CI: 0.54-1.2, P=0.39), respectively.

Discussion

Using a mathematical modeling approach, this study estimated the per-sex-act and perpartnership FtoMTPs of HIV and HSV-2 among a cohort of young males in South Africa. It suggested that HSV-2 infection enhanced HIV acquisition and conversely, that HIV infection could enhance HSV-2 acquisition. Furthermore, this study provided evidence of a protective effect of MC on HSV-2 acquisition by young males.

This study has some limitations: a) we used data obtained among men aged 18 to 24, recruited for a MC trial and thus not representative of the general male population; b) condom use was collected by partnership. Thus, condom use per sex act was not directly available and had to be extrapolated; c) we cannot exclude some bias since the HIV and HSV-2 serostatuses of the female partners of each male were not directly assessed but estimated. Nevertheless, in estimating the males' exposure to these two viruses for each of their sexual partnerships, we were careful to take into account the age of their female partners and the sexual behavior by age of the females of the same community; d) we also cannot exclude bias due to misreporting of sexual behavior of males and females. However, this limitation is inherent to all studies of this type.

Our estimation of HIV FtoMTP per sex act is consistent with recent values obtained by a meta-analysis of transmission studies conducted in developing countries [START_REF] Boily | The risk of HIV-1 infection per sexual contact in absence of antiretroviral therapy: a systematic review and metaanalysis of observational studies[END_REF]. In particular it is consistent with the results of a recent HIV-1 per-sex-act FtoMTP estimation conducted in a Kenyan prospective cohort study in the context of multiple partnerships [START_REF] Baeten | Female-to-male infectivity of HIV-1 among circumcised and uncircumcised Kenyan men[END_REF]. In contrast, our estimation of HSV-2 FtoMTP per sex act is higher than the comparable published values obtained in two studies conducted among discordant couples, mostly in developed countries [START_REF] Wald | Effect of condoms on reducing the transmission of herpes simplex virus type 2 from men to women[END_REF][START_REF] Corey | Once-daily valacyclovir to reduce the risk of transmission of genital herpes[END_REF]. Several factors may explain this difference [START_REF] Wald | Effect of condoms on reducing the transmission of herpes simplex virus type 2 from men to women[END_REF][START_REF] Mastro | HIV type 1 transmission probabilities: estimates from epidemiological studies[END_REF]. Using discordant couples can create a selection bias for two reasons: a) couples having a low average FtoMTP are more likely to be discordant, b) people engaged in long-term relationships have a lower FtoMTP because HSV-2 transmission decreases as a function of the duration of the partnership [START_REF] Corey | Once-daily valacyclovir to reduce the risk of transmission of genital herpes[END_REF].

This study was conducted among young men who are for the most part unmarried or not living as married. The short duration of their partnerships and the low number of sexual contacts [START_REF] Auvert | Randomized, controlled intervention trial of male circumcision reduction of HIV infection risk: the ANRS 1265 Trial[END_REF][START_REF] Auvert | HIV infection among youth in a South African mining town is associated with herpes simplex virus-2 seropositivity and sexual behaviour[END_REF] may explain why per-partnership FtoMTPs were only about 4 times higher than the corresponding per-sex-act FtoMTPs for HIV and HSV-2.

In this study, which used a mathematical modeling approach, the ITT and as-treated (AT) protective effect of MC on the per-sex-act and per-partnership FtoMTPs of HIV were almost identical to the reducing effect of MC on HIV incidence estimated using a statistical approach and the same dataset [START_REF] Auvert | Randomized, controlled intervention trial of male circumcision reduction of HIV infection risk: the ANRS 1265 Trial[END_REF].

In both ITT and AT analyses, we observed a reducing effect of MC on HSV-2 acquisition by males, which was significant for the AT analysis. This effect was estimated by ensuring that the effect of MC on HIV and the effect of HIV on HSV-2 were taken into account. The difference between ITT and AT analyses may be partly due to the diluting effect of crossovers. This reducing effect of MC on HSV-2 acquisition is consistent with the conclusions of a meta-analysis [START_REF] Weiss | Male circumcision and risk of syphilis, chancroid, and genital herpes: a systematic review and meta-analysis[END_REF] and the results of the Rakai MC trial [START_REF] Tobian | Trial of Male Circumcision: Prevention of HSV-2 in Men and Vaginal Infections in Female Partners, Rakai, Uganda[END_REF]. It provides additional evidence supporting the promotion of MC in Africa as a method to reduce the spread of STIs such as HIV and HSV-2. This effect should be further investigated by pooling the results of the three circumcision randomized trials.

We found a significant reducing effect of reported condom use on the perpartnership FtoMTPs of HIV and HSV-2. The fact that condom use per sex act was extrapolated in addition to its possible misreporting may have contributed to the large confidence intervals found for the effect of reported condom use on the per-sex-act FtoMTPs of HIV and HSV-2.

The significant enhancing effect of male or female HSV-2 positive status on the FtoMTP of HIV, as shown in this study and in many others, is now well accepted [START_REF] Corey | The effects of herpes simplex virus-2 on HIV-1 acquisition and transmission: a review of two overlapping epidemics[END_REF][START_REF] Wald | Risk of human immunodeficiency virus infection in herpes simplex virus type 2-seropositive persons: a meta-analysis[END_REF][START_REF] Freeman | Herpes simplex virus 2 infection increases HIV acquisition in men and women: systematic review and meta-analysis of longitudinal studies[END_REF][START_REF] Brown | and prevalent herpes simplex virus type 2 infection increases risk of HIV acquisition among women in Uganda and Zimbabwe[END_REF][START_REF] Weiss | The epidemiology of HSV-2 infection and its association with HIV infection in four urban African populations[END_REF]. This study showed a significant enhancing effect of HIV status on the FtoMTP of HSV-2. Such an effect could be due to transient immunosuppression during the acute stage of HIV infection which may increase HSV-2 acquisition and/or increase HSV-2 infectiousness among HIV-infected females. It should be further investigated.

The findings of this study confirm and reinforce the interpretation of a multisite study which found that sexual behavior and prevalence levels of MC and HSV-2 were key factors in understanding the heterogeneity of the HIV epidemic in Africa [START_REF] Auvert | Ecological and individual level analysis of risk factors for HIV infection in four urban populations in sub-Saharan Africa with different levels of HIV infection[END_REF][START_REF] Buve | multicentre study on factors determining the differential spread of HIV in four African cities: summary and conclusions[END_REF]. It appears that the interactions between HIV, HSV-2, sexual behavior and MC should all be taken into account to understand the heterogeneity of the HIV and HSV-2 epidemics in Africa.

Studying the FtoMTPs of both HIV and HSV-2, we found that cofactors such as MC and the presence of the other virus had a strong effect on these FtoMTPs. Hence, it is important for transmission studies to carefully take into account these cofactors, in order to obtain comparable results independent of the prevalence of these cofactors in the study population.

The results of this study are consistent with our current knowledge of the epidemiology of HSV-2 in Africa and the synergy between the HIV and HSV-2 epidemics in this part of the world. The fact that HSV-2 treatment (acyclovir 400 mg twice daily) does not prevent HIV acquisition [START_REF] Celum | HSV-2 Suppressive Therapy for Prevention of HIV Acquisition: Results of HPTN 039[END_REF], most likely because the current HSV-2 treatment does not eradicate HSV-2, does not disprove the facilitating effect of HSV-2 on HIV acquisition. In addition to the reducing effect of MC on HIV acquisition by males, the effect of MC on HSV-2 is another argument in favor of the roll-out of MC in African countries where most males are uncircumcised [START_REF]New Data on Male Circumcision and HIV Prevention: Policy and Programme Implications[END_REF]. Modeling studies are needed to better understand the interactions between HIV, HSV-2, MC, sexual behavior including condom use, not only in the short term, as studied by randomized controlled trials, but also in the long term.

HIV and HSV-2 statuses of females

For females, the probability of being infected was estimated based on data from a published survey [START_REF] Corey | The effects of herpes simplex virus-2 on HIV-1 acquisition and transmission: a review of two overlapping epidemics[END_REF]. Indeed, the statuses of the males' partners are unknown. These statuses e k (k=0, 1, 2, 3) are expressed as four configurations (states) detailed in Table 1. For each female, the covariates are age, HIV and HSV-2 statuses and reported number of sexual partners in the past 12 months. The probability of being in state e k was estimated by a multi-class logistic regression. This probability depends on age, q and the reported number of sexual partners in the past 12 months, y. Thus, we obtain the following formula: .

∑ = + + = 3
The reported number of sexual partners in the past 12 months was modeled by a Poisson distribution Y, which mean λ was estimated from the survey data using the maximum likelihood method. Hence:

∑ = × = = 0 ) , ( ) ( ) ( y k r k y q y Y P q π π
= l i υ γ
denotes the use of condom with a partner (0 otherwise), and 1

) ( = υ i c
denotes a circumcision (0 otherwise).

Per-sex-act transmission model 2.2.1 Notations

We define the transmission probability per sex act of a given virus as the probability that a person becomes infected after a sexual contact with a person infected with the virus. Let: , q r, integers: r r r r q q q q q r pm q q q q q q r qm q q q q q q r rm

υ υ υ υ υ υ υ υ υ υ υ υ ϕ ϕ ϕ i i s t j l i l i l i l i l i l i s t t j l i l i l i i q r qm q r um q r pm e e L ; ) , ( ) , ( ) , ( 1 )

Per-partnership transmission model 2.3.1 Notation

In this setting the transmission probability refers to the transmission probability per partnership from a woman to a man not infected. Thus, the previous model for transmission probability can be used with the following convention: ) 2 , ( hsv hiv P denotes the transmission probability per partnership of HIV from a woman not infected by HSV-2 to a man not infected by HSV-2.

Table 1 : Number of HSV-2 HIV infections per follow-up visit Follow-up visit Number of HSV-2 infections*

 1

	Number of	Number of co-
	HIV infections*	infections*

Table 2 : Multivariate risk factors of the female-to-male per-sex-act and per-partnership transmission probabilities of HIV

 2 In one of the partners. If HSV-2 is present in both partners the relative risk (RR) becomes RR 2 .

		Relative risk (95% CI) of the	Relative risk (95% CI) of the
	Cofactor	per-sex-act transmission	per-partnership transmission
		probability	probability
	Presence of HSV-2*	3.0(1.01-7.3) P=0.048	3.7(1.7-6.9) P=0.003
	Circumcised male	0.24 (0.11-0.44) P<0.001	0.25 (0.12-0.44) P<0.001
	Reported condom protection	0.90 (0.30-1.9) P=0.65	0.47 (0.17-0.92) P=0.021

*

Table 3 : Multivariate risk factors of the female-to-male per-sex-act and per-partnership transmission probabilities of HSV-2 Cofactor Relative risk (95% CI) of the per-sex-act transmission probability

 3 In one of the partners. If HIV is present in both partners the relative risk (RR) becomes RR .

	Relative risk (95% CI) of the
	per-partnership transmission
	probability

*

Table 4 : Univariate effect of male circumcision on the female-to-male transmission probabilities of HIV and HSV-2 Transmission type Circumcision status Transmission probability* (95% CI)

 4 Averaged on condom use and on the cofactor effect of the other virus.ContributionsSG.M. and B.A. contributed equally to this work. DT and AP collected the data. AP, SGM, JB, EPNN, EG and BA analyzed the data. AL, JB, CL and PL wrote some parts of the paper and edited the entire manuscript.

	Relative Risk
	(95% CI)

*

Table 1 : Statuses of men and women. 2 Notations and models 2.1 Settings

 1

			.
											HIV HSV-2
					e 0				-	-
					e 1				+	-
					e 2				-	+
					e 3				+	+
	The HIV and HSV-2 statuses of males are determined at recruitment	υ	=	0	and at the end of
	each of the 3 follow-up visits	υ	=	, 1	3 , 2	.
	Consider an individual i . For	υ	=	, 1	3 , 2	, consider the period between visits	υ	-	1	andυ ; then,
	for that period, the observed data consist of:
	) s , the number of partners of i , (υ i		) r υ , his number of sexual contacts with his th , ( l i l partner,
	) q υ , the age of his th , ( l i l partner,		(	,	)	1

Foundation (USA) grant 33759, NICD (South Africa), INSERM (France), SACEMA (South Africa), SCAC (France Embassy, Cameroon).

) 2 , ( hiv P be the transmission probability per sex act of HIV from a woman not infected by HSV-2 to a man not infected by HSV-2, not circumcised and not condom user.

) , 2 ( hiv hsv P be the transmission probability per sex act of HSV-2 from a woman not infected by HIV to a man not infected by HIV, not circumcised and not condom user.

) 1 ( RR be the relative risk of HIV transmission to males associated with the presence of HSV- 2) 2 ( RR be the relative risk of HSV-2 transmission to males associated with the presence of HIV ) 1 , 0 ( RR be the relative risk of HIV transmission to males associated with condom use ) 0 , 1 ( RR be the relative risk of HIV transmission to males associated with male circumcision ) 2 , 0 ( RR be the relative risk of HSV-2 transmission to males associated with condom use ) 0 , 2 ( RR be the relative risk of HSV-2 transmission to males associated with male circumcision.

Probabilities of transmission between two visits

We derive the expression of the transmission probability per sex act, P ~, for a male i with his th l partner between the visits 1 -

is the transmission probability of HIV when neither the man nor his partner is infected by HSV-

(

is the transmission probability of HIV when either the male or his partner is infected by HSV-

is the transmission probability of HSV-2 when both the male and his partner are infected by HIV.

Likelihood

) ) is obtained as follow:

) , 2 ( hiv P denotes the transmission probability per partnership of HSV-2 from a woman not infected by HIV to a man not infected by HIV.

Probabilities of transmission between two visits

When a male i is with his th l partner between the visits 1 -υ and υ (

), the transmission probabilities per partnership are given by the same formulas as those of section 2.2.3.

Likelihood

The likelihood is obtained by setting 1 ) , ( = l i r υ for all , , , l i υ and using the formulas of section 2.2.3.


Critical Han Studies Symposium & Workshop

April 24-27, 2008 -Stanford University Paper title :

"Class", "Race" and Language : Imagining China and the Discourse on the Category "Han" in the Writing of Marxist Revolutionary Qu Qiubai (1899-1935) Florent Villard, IETT (Institute for Transtextual and Transcultural Studies), University of Lyons (Jean Moulin)

The primary aim of this paper is to investigate the discursive peregrinations of the category "Han" in the writings of the Chinese revolutionary theoretician and activist Qu Qiubai (1899-1935) ; this paper does not then deal with the theoretical and political work carried out by Qu Qiubai as the former leader of the Chinese Communist Party during the nineteen twenties, but rather focuses on the texts concerning cultural and linguistic issues that he wrote at the beginning of the thirties after retiring from direct political activism. I intend to analyze, through Qu's discourse on language and writing, how the category minzu (nation/ethnicity/race) and more specifically the idea of a Hanzu or Han minzu are deployed and integrated in his theoretical writing.

In his writing of the early nineteen thirties, the author made a singular use of the signifier "Han" to talk about the language/writing of the Han (hanzi, hanyu) as that of a racial or ethnic group understood as hanzu. Narrating the history of the cultural hegemony of the Han in Asia and criticizing the policy of assimilation (tonghua), Qu elaborated a discourse which articulated and mobilized, sometimes in a contradictory manner, the category Han both as a "race" and as a social class.

Going beyond the race/class dialectic, we will try to show that these texts question the territorial, cultural and ethnic boundaries of "China" and its homogeneity. Even if the author integrated the Han category in his discourse, I argue that his use of the notion in theoretical works dealing with the linguistic identity of China tends to deconstruct the modern invention of this homogeneous ethnic community in two different but associated ways : the assertion of a linguistic multiplicity within the Han group and at the same time the identification of the traditional Han language and writing (hanzi, hanyu) with a dominant social class which overcomes this internal diversity.

Qu Qiubai and the modern tradition of the category "Han"

As Dru Gladney has said, the notion of Hanzu or Han minzu in the sense of an ethnic community as the cohesive body of the nation is "an entirely modern phenomenon, arising with the shift from empire to nation". [START_REF]Clashed Civilizations ? Muslim and Chinese Identities in the PRC" in Making Majorities: Constituting the Nation in Japan[END_REF] The nationalist ideology in China, embodying the will to invent a political nation-state, goes back to the beginning of the twentieth century as a consequence of and as an answer to the Western imperial domination: nation as a concept and as a political form was to be used by Chinese intellectuals to build a new and strong state able to compete among the family of nations. The last hundred years have witnessed the political construction of the Chinese nationstate, and this nationalist project has been sustained by the volontarist constitution of a cultural and linguistic homogeneity. Even if, as in all nationalist narratives, this history/story functions as a fiction, the nationalist ideology which invented boundaries between China and the outer world (these being not only political and state boundaries but also cultural, linguistic and ethnic ones) is nowadays deeply inscribed in the Chinese collective imaginary. In the modern construction of a Chinese nation, the Han as an ethnic/racial community functions as a major component of the discursive construction of the nation as one and homogeneous. The category Han is now an integral part of the Chinese collective consciousness and corresponds, in the Chinese society, to what the Graeco-French social philosopher Cornelius Castoriadis called a "social imaginary signification". [START_REF] Castoriadis | Domaines de l'homme : Les carrefours du labyrinthe[END_REF] From the first conceptualization of a "Han race" by the anti-Manchu revolutionaries to the invention of the "Han nationality" by the communists, the homogeneity of the Han community has never been questioned by Chinese nation-builders. At the same time, the fact that the territory referred to as China under the Qing dynasty greatly exceeds the physical habitat of the so-called Han, obligated Chinese nation-builders -both nationalists and communists -to integrate in different ways the inner others in their national narratives. The complex palimpsest of the narration of the "Chinese nation" is composed of different strata. The polysemy and ambiguities of the notion of minzu is the result of multiple intertextualities between the Japanese (minzoku), the European (nation), the Russian (natsiya, narodnost) and Chinese translations, besides being the consequence of the re-invention and transformation of the meanings of minzu within the Chinese intellectual and political space according to various political and ideological orientations of the speakers. It is acknowledged that the first occurrences of the word minzu appeared at the end of the nineteenth century when theoreticians of Chinese nationalism, both reformist and revolutionary, borrowed this word from the Japanese. [START_REF] Weiner | On the history of this term, see Fang Weigui方维规, Lun jindai sixiangshi shang de "minzu[END_REF] The word had been constructed by the Japanese to translate the modern-Western notion of the "nation" while the idea of nation came along with the European nineteenth century "scientific " discourse of the race struggle. In the political context of the anti-Manchu discourse developed by revolutionaries at the end of the Qing dynasty, notions such as "minzu " and "Hanzu " had a racialist connotation in the texts of nationalist propagandists such as Zhang Binglin and later Sun Yat-sen. [START_REF]For the various meaning of minzu and zhongzu in late Imperial China see Kauko Laitinen, Chinese Nationalism in the Late Qing Dynasty: Zhang Binglin as an Anti-Manchu Propagandist[END_REF] The connotations of the concept of Hanzu in the writings of a Chinese intellectual in the thirties cannot be understood without examining the semantic history of the signifiers of the communitythat is national, ethnic and racial. The imaginary of the "nation" and its boundaries is a recent phenomenon in China, but it is interesting to note that in Qu's texts we can already find different theoretical and textual traditions which give it a polysemic sense often veiled by the translation of signifiers such as hanzi, hanyu, hanzu, Zhongguo, minzu, and so on.

As a Marxist, Qu Qiubai would probably have contested an essentialist, biological, race-based definition of Han, it is however obvious that, like his contemporaries, he had integrated the notion of a Han ethnic majority as a dominant discursive category through which to read China's politics. [START_REF] Qiubai | Xiandai minzu wenti jiangan " 现代民族问题讲案[END_REF] In Qu's texts, minzu is related to the Soviet theoretical tradition concerning "nationalities " and " national question " policies. This intertextual track is strenghtened by the fact that Qu spent many years in Moscow and spoke Russian fluently. The theoretical reference here is, of course, to Stalin's 1913 definition of natsiya or "nationality " . [START_REF] Staline | Le marxisme et la question nationale et coloniale[END_REF] In this regard, minzu as a community of the capitalist stage identified by the "four common " criteria of the Stalinist definition is explicit in the author's political texts written in the nineteen twenties on the so-called national and colonial question.

When he mentions the ruoxiao minzu or "weak and small nationalities " , he refers to the ethnocultural communities living whithin political entities such as the Soviet Union or China. [START_REF]Qu Qiubai's texts in Minzu wenti wenxian huibian, 民族问题文献汇编 1921-1949, Beijing, Zhonggong zhongyang dangxiao chubanshe[END_REF] The set-phrase "shaoshu minzu " or " national minorities " , which had a Comintern origin, already appears in the communist party literature of the nineteen twenties. [START_REF] Liu | Frontier Passages: Ethnopolitics and the Rise of Chinese Communism[END_REF] The term was used to refer to the non-Han communities within the Chinese space, including refugees from various countries and foreign residents in the concessions. [START_REF]Zhonggong liu jia er zhong quanhui taolun zuzhi wenti jielun[END_REF] Qu uses the word minzu both for "small " nationalities and for the Han but we must bear in mind that in the theoretical framework of the communists, these communities were not located at the same historical stage. In accordance with the communist literature of that time, we can say that in most cases the Han minzu was seen as the majority, as overlapping with China, and as historically in advance compared to the other nationalities in the Marxist socio-economic framework.

My purpose here is to question the position of the Hanzu or Han minzu as an ethnic category in relation to Zhongguo or China seen as a territory, a political entity and also a language in the writings of the author and to point out the contradictions or ambiguities in his discourse. As I mentioned earlier, the Han question was not the main concern of Qu's texts in the nineteen thirties, it was nevertheless a prevalent element in his discourse.

The author wrote extensively on the question of a common language for China which would not be a "national language " or "state language " . His critics focused on the linguistic project of invention of a standardized and uniform Mandarin-based "national language " (guoyu). [START_REF]Qu's essays on language and writing in the early thirties include «Zhongguowen he Zhongguohua de xianzhuang " 中国文和中国话的现状[END_REF] In his texts, the author identified different linguistic communities referring to both the Hanzu and other nationalities. I believe that the discursive relation between the Han, the nationalities and Zhongguo in Qu's thinking can be clarified by focusing on the question of language. It is a way to elucidate how a Chinese revolutionary in the nineteen thirties understood and imagined the Chinese identity, that is to say China in its political, spatial, cultural and linguistic dimensions, by revealing some ambiguities within his discourse and identifying questions on his thinking concerning the relation between the Han, the "others " and China. Are the Han located in the same level as the "others " in his imaginary of China ? Is the Han category a synonym of Zhongguo in his texts ? Does the heterogeneity and diversity of the "others " necessarily imply a homogeneous and unique Han majority ?

The Han as China I would first like to insist on the arguments in Qu's essays which give credit to the habitual thesis according to which the Han category is synonymous with Zhongguo and, which consequently establishes the other nationalities as being outside this relationship. Let me quote here the author in a critique of the assimilationist position (tongwen zhengce) held by the poet and May Fourth movement the activist Liu Dabai (1880-1932). Qu aimed at proving that China, unlike in the past, no longer had the power and the dominant position -economic and by extension cultural-which would have allowed her to impose an assimilationist policy on "alien races" (yizu In this last sentence, what is intended by Zhongguo is a political space or entity and the other "ethnicities " refer to ethno-cultural communities. The author clearly sets these two different types of communities apart, and the relationship between Zhongguo, as a political power, and the nationalities allows no confusion in this quotation. But the situation gets more complicated and ambiguous when we try to understand how the third term of the conversation -that is to say the Hanzu or Han minzu -came to be included within the discursive relationship between Zhongguo and its "inner others " . Qu uses the words Hanzu and Zhongguo de Hanzu to talk about a dominant culture -symbolized here by the characters Han -which deeply influenced many Asian countries in the past. Later in the essay, as he deals with the question of the assimilation of the "alien races" (yizu) (Xinjiang, Mongolia and Tibet), he uses the word Zhongguo and conflates this term with the notion of Hanzu. In the same way, it seems clear that in the last question quoted above replacing minzu by Hanzu would sound like a non-sense: Does China still want to apply this kind of [assimiliationist] policy to tackle the Hanzu ? It is obvious that in Qu's imaginary, the idea of China as limited to the Han community has been partly integrated. Qu gives a particular status to the Han nationality which finds its origin in the nineteenth-century nationalist invention of the category of the Han as a majority ethnic/racial community in China. This example follows the Communist party's position on nationalities at the end of the nineteen twenties which pointed to the possibility of future independance for non-Han nationalities on the grounds that they were not naturally included within the Chinese nation. It is also coherent with Qu's position in his political texts written in the nineteen twenties where he made clear that for him "Zhongguo minzu " only included the Hanren, and within the Han themselves Qu said that the commoners were the sole representatives of the Chinese nation. [START_REF] Liu | Qu Qiubai Wenji Zhengzhi Lilun Bian瞿秋白文集 政治理论篇[END_REF] China as a language, China as a space

Saying that in Qu Qiubai's texts China is synonymous to the Han would be too simplistic a resolution of the complexity of the relations between the category Han, the nationalities and Zhongguo as a spatial, political and historical entity. I will now go a little further by questioning the relationship and differences between Qu's imaginary of the territorial and linguistic Chinese/Han space. The author recurrently used the expression Zhongguo yuzu or "Chinese linguistic family " as a synonym for "the languages of the Han " . As mentioned above, Qu insisted in saying that the non-Han nationalities were not included in the notion of Zhongguohua:

可以说 : 中国话是所谓中国语族的意思。因为中国境内 --除出苗,黎,西藏,蒙古等等不同的民族的言语之外 --同是汉族的言语又有许多种. [START_REF] Qu | Zhongguowen he Zhongguohua de xianzhuang[END_REF] We can say that the Chinese language means the Chinese family of languages because within the Chinese [Zhongguo] space, -besides the languages of different nationalities such as Miao, Li, Yi, Tibetan or Mongol, there are also numerous varieties Han nationality language.

In one and the same sentence here, we can spot a double use of the concept Zhongguo : first, Zhongguo as a geographic territory in Zhongguo jingnei; and secondly, Zhongguo defining a linguistic community in Zhongguohua where the notion only refers to a limited Han ethnic group. On the other hand, Zhongguo as a territorial entity subsumes different nationalities or minzu including the Han. The"geographic concept" of Zhongguo jingnei implies the idea of an inner and an outer China, and the term used here also refers to the old Qing dynasty imperial territory. If a Chinese map involving a sovereign territory with fixed and precisely delimited boundaries belongs to a strictly modern imaginary, it is a historical fact that the Qing had already established boundaries with their neighboring states but its "frontiers policy operated within 'zones' rather than along 'lines' " . 14 This meaning of Zhongguo as a political territory including different nationalities is confirmed in another text by Qu where he notes that ''[a]s a nation, China is not simply the Han nationality; there are also the Hui, the Tibetans, the Mongols, the Li, the Miao, the Yi " [中国不但是汉族的民族, 还有回族, 西藏族, 蒙古族, 黎, 苗, 彝族.]. [START_REF] Qu | Xin wenzi de Zhongguowen (Sin-Zongod wenze gemin)[END_REF] The vision of China as a multinational state is in apparent contradiction with his Han-China conception. Therefore we can wonder whether minzu has the meaning of a political community here as in the expression Zhonghua minzu ?

If we consider language as a major ethnic criterion we can say that the author made a distinction between an ethnic Han China and a territorial, historical, imperial China overcoming this ethnic identity. This split within a Chinese space can be read as the classic distinction made by the communists, and by Qu in his texts, between "China proper " or Zhongguo benbu and "frontier regions " or Zhongguo jiangbu. As Liu Xiaoyuan remarked, if this distinction was used by the communists within the Marxist economic theoretical framework, it still echoed older "in-grained" conceptions of the ''frontier administration'' or bianzheng. [START_REF] Liu | Communism, Nationalism, Ethnicism, and China's National Question, 1921-1945[END_REF] This internal boundary between "proper'' and ''frontier'' China also corresponded to ethnic boundaries between the Han and the non-Han read in terms of historical differences, that is to say economic differences, since the Han were considered as advanced compared to the "alien races" (yizhong minzu): "When applying the standard Marxist political-economic analysis to China's inter-ethnic situation, the CCP made a stark contrast between the burgeoning capitalist" China proper (benbu) and the "nomadic, primitive" non-Han frontiers (jiangbu) " . [START_REF] Liu | [END_REF] contesting Han ethnicity in emphasizing the plurality of languages

The distinction between the homogeneous Han as the Chinese proper and the heterogeneous others within a global Chinese space or Zhongguo jingnei covering both territories is however put in questioned by the author's emphasis on the plurality of languages or dialects spoken within the Han community itself. If again the author gives a cohesive identity to the Han with the notion of linguistic family, he however recurrently insists on the inner diversity within this "family" and includes in it all the languages talked inside the "Han" Chinese world such asShanghainese, Cantonese, the language of Beijing, which were all subsumed under the concept of a "Chinese linguistic family", a notion which means, according to the author, Zhongguohua or "Chinese languages " . In many essays, as he criticizes the guoyu project, Qu considers a national mandarinbased language which would be imposed on the Han population as a violence committed against the diversity of idioms spoken in China :

对于他们绝对不应当实行所谓中国话的 "国语统一 "的政策。就是汉族自己的许多种方言,也不能够实行强迫 的统一政策。 [START_REF] Qu | Xin wenzi de Zhongguowen (Sin-Zongod wenze gemin)[END_REF] A policy of so-called Chinese (Zhongguohua) "national language (guoyu) unification " must absolutely not be applied to them [the nationalities]-just as a policy of coercive [linguistic] unification cannot be applied to the numerous dialects (fangyan) of the Han themselves.

It is a fact that the homogeneity of the Han majority has seldom been questioned either by Chinese nationalist intellectuals or by "scientific" scholars. Dru Gladney notes that "discussions of China generally take cultural homogeneity for granted" and argues that "there is a tremendous ethnic diversity among its "official" minority nationalities, but also that there are equally important cultural differences among China's majority population, identified as the Han people." [START_REF] Gladney | Dislocating China: Muslims, Minorities, and Other Subaltern[END_REF] Significantly, the division between the Han as the Chinese ethnic group and the other nationalities does not imply in Qu's texts the unity of the Han. Qu even goes further in rewriting history and imagining the past fragmentation of China into numerous different nations and the constitution of multiple literary languages within the territory. [START_REF] Qu | Zhongguowen he Zhongguohua de xianzhuang[END_REF] According to Qu, the "Chinese family of languages" can be compared to the "Latin family of languages" and, in this perspective, he insists on the fact that there were as many differences between the European languages as there were between the Chinese "Han" languages. If we compare this imaginary to China's contemporary situation, it is relatively explicit that today in the multinational People's Republic, the so-called official "national minorities" or shaoshu minzu 少数民族 function, in their diversity, as the other of the unique, homogenized Han majority.

I would say that although it cannot be denied that Qu Qiubai still relied upon the category of the Hanzu as an ethnic community and imagined it through a Marxist-Leninist socio-economic framework, at the same time, dealing with the question of language, which is one of the most important criteria in defining ethnicity, he repeatedly noted the extreme diversity within the Han and in a sense deconstructed or at least contested an essentialist vision of the Han-based identity of the Chinese modern nation.

The Han as a class which overcome China's boundaries

In taking into account the internal diversity of the Han, I argue that the author helps us to imagine in a singular way the traditional relationship between the apparent Han majority, the ancient "alien races" or modern "national minorities" and the old vassal states (shuguo and keguo) outside the Chinese imperial boundaries. Having taken for granted the linguistic diversity within "China proper", Qu articulates this reality with the construction of a historical metanarrative involving a

Han/Chinese culture (Hanzi, Hanwen, Hanyu) which formerly imposed its domination within the space named "Tianxia" that is to say a more or less large territory around the middle point of the Empire. [START_REF] Qu | Luomazi de Zhongguowen haishi ruomazi de Zhongguowen ?[END_REF] When narrating the ancient "Chinese" cultural domination over Asia, the authors stands, unsurprisingly, on a historical materialist point of view and insists on the "Hanzu" cultural domination as the consequence of its position as "advanced nation" in political-economical terms.

In other words, if Japan or South-East Asian nations used Han characters and Han writing, it was, according to Qu, the result of an economic domination and of the political superiority of the Han.

This cultural and linguistic hegemony was not read by Qu as a consequence of a race struggle, as the domination of one nation or ethnicity over another, it was seen rather as the hegemony of a social class, that is the bureaucracy and the gentry of the Chinese imperial state. That is, the common, at least in appearance, cultural and linguistic identity (Confucian culture and Classical Chinese) in Asia was interpreted as the hegemony of a dominant class. It is not surprising to hear a Marxist using the argument of the class struggle to narrate historical evolution. But the shift, in its interpretation, from ethnicity to social class has profound implications on the way he imagines China and its identity, especially its cultural and linguistic identity. As he writes on the relations between this dominant class and the local populations (minzhong, pingmin), we can again witness a destabilization of the ethno-cultural frontiers or essential differences between a Han and a non-Han cultural space. Hence the fact that in the theoretical imaginary of Qu Qiubai, the cultural and linguistic diversity under the imperial bureaucracy cannot be understood only in terms of "Proper China" and "Frontiers China" or Han and non-Han populations and territory. This inner traditional frontier is here partly erased because Qu considers that the diversity under the dominant class also exists within the Han territory itself. Let me quote Qu' s construction of a fascinating comparative perspective which helps us to understand his geopolitical imaginary :

欧洲中世纪各国的绅士贵族用拉丁话,可是,各国民众所说的话,却仍旧是各国本地的话[...]远东的古代,各国 绅士都多多少少用过汉文,然而各国民众所说的话,却仍旧是各地的"土话"[...]就全中国本部来说,古代 个省的秀才举人的确用的是同一种的汉文文言, 可是中国个省的民众说的却是北京话, 广东话, 上海话... [START_REF] Qu | Luomazi de Zhongguowen haishi ruomazi de Zhongguowen ?[END_REF] During the middle ages, the European aristocratic class from different states were all using Latin while the languages of the people within these states were all local vernaculars. [...] In the Far East in ancient times, the gentries of different kingdoms used the Han written language, however the peoples of these different states spoke there own local idioms [...] Over the entirety of China proper, scholars of the various provinces province all used the same Han classical language while what the ordinary people of China's various provinces spoke was Beijing dialect, Cantonese, the Shanghainese and so on... It is not my purpose here to assess the scientific credibility of Qu's historical reading and knowledge, but to track the way he imagines and articulates spaces, populations, languages and cultures to inform his discursive (de)construction of the Chinese nation's identity. Qu develops a comparative approach articulating three different socio-historical and political spaces so as to contest the cultural assimilationist discourse which claimed that in the past China had always been able to acculturate alien races, owing to its uniform Han writing system. We can nevertheless notice some basic differences between these three spaces: Qu uses the concept of «China proper" and thus naturally implies the existence of another and distinct part of the Chinese territory. Identifying local identities under these geographical spaces, he also mentions "sheng " or province in the Chinese example and deploys the term "guo " or country when dealing with Europe and Asia.

However, the numerous arguments the author puts forward in order to compare the European and the Chinese situations tend to deconstruct China as a nation even when reduced to the Han community. He objects to a Chinese or Han linguistic identity by insisting on the fact that this superficial unity (biaomian de shangceng de tongyi) and cultural homogeneity was made by the "ruling aristocratic bureaucracy" (guanliao guizu tongzhi). [START_REF] Qu | Zhongguowen he Zhongguohua de xianzhuang[END_REF] He reads China's linguistic differences in a vertical manner: multiplicity of local idioms among the people, unity of language and culture in the dominant class.

Frank Dikotter reminds us that Liang Qichao "rearticulated traditional social hierarchies into a new racial taxinomy". 24 Similarly, Balibar (following Foucault) noticed that the old classical myths of race all have something to do with class distinction and especially with aristocratic identity. [START_REF] Balibar | Racisme et nationalisme[END_REF] In reading the word "class" behind the word "race", it is as if the texts of Qu were inverting the process by which these two concepts had been linked.

Etienne Balibar calls "fictive ethnicity" the way populations have been "represented in the past or in the future as if they constituted a natural community, possessing an identity of origin, culture, and interests which would transcend individuals and social conditions". 26 He adds that there are two common means to invent this fictive ethnicity which are language and race. In China, since the end of the nineteenth century, the category Han has been the major figure of this "fictive ethnicity". Qu's writings are deeply imbued with this imaginary of the Han "fictive ethnicity", a theoretical conceptualization produced by the Western political modernity and transformed in the Chinese historical context.

Qu's discourse is however disrupted by his internationalist and Marxist ideological position which leads him to read the interests and logic of the class struggles behind the signifiers of the "nation". In this perspective, a "national language" or old Mandarin, along with its characters, do not represent an ethnic community or even a people but only the culture of the dominant class artificially veiling the internal diversity within China. His cultural work of the nineteen thirties however tended to negotiate class problematics without neglecting local identities -especially linguistic identities -which take into account but also tend to overcome traditional ethnic categories.

The essays by Qu mentioned here were written during a crucial historical moment for China which preceded the political invention of a national culture and language by Mao Zedong and his advisors during the Yan'an period, and elaborated and implemented by the communist state after the civil war. The Chinese cultural and linguistic homogeneity and national consciousness which seems so natural now was still questioned at the beginning of the nineteen thirties by intellectuals such as Qu Qiubai. He never wiled political power and did not live to witness the construction of the People's Republic of China, but, without doubt, he would have been perturbed to see a state imposing a common language or culture while conceiling class hierarchies and local diversities.

  ). The dominant imperialist nations were now European countries and they were imposing their cultures on Asia and notably China's old vassal states. It is interesting to notice that in this passage Zhongguo and the In the historical past, the Hanzu of China was the most culturally advanced nation. In the Far East Annam(i.e.Vietnam), Siam, Burma, Korea and Japan have all been influenced by the Han and have adopted the Hanzu's Han characters. [...] Nowadays, we must recognize that China's own cultural level on the world political-economic stage is rather backward.

	Han are conflated :
	中国的汉族在古代历史上固然是文化先进的民族,远东的安南,暹罗,缅甸,高丽,日本都受着他的影响,而 采用汉族的汉字。[...]现在,中国自己的文化程度,在世界的政治经济舞台上,不能不承认是比较落后了。日 本是超越了中国一世纪。[...]其他的远东民族,都自然在文化上接受先进的欧美影响,而不再受中国的领导了 。中国现在还说要同化异族,用什么东西去同化人家呢 ?[...]中国还想用这种政策去对付蒙古西藏新疆吗?不知 道联合这些民族去反抗帝国主义? 11

Japan is one century ahead of China. [...] [At the same time], other Far Eastern minzu have naturally come under the cultural influence of advanced Europea and America and are no longer under China's dominance . China is still talking about the acculturation of alien races [yizu], but with what does China want to acculturate others ? [...] Does China still want to apply this kind of [assimilationist] policy to tackle Tibet, Mongolia and Xinjiang ? Is China capable of federating these minzu to resist imperialism ?