1. Introduction

The condom use resistance is far from being a thing of the past. It is relevant in our modern society and deserves special attention is paid to it. And because, despite awareness campaigns made about the dangers of HIV and AIDS especially its defenses, it persists in the African population, behavior of refusal to use condoms during sexual acts. This is even more true and even strengthened in Central Africa. It is, therefore, this region is the second most affected by the HIV epidemic after the Southern region. The prevalence, depending the country, varies: 4.9% in Centrafric (MICS IV, 2010), 5% in Equatorial Guinea (UNAIDS, 2009), 4.1% in Gabon (EDSCG, 2012), 3.2% Congo (ESIS, 2009), 4.3% in Cameroon (EDS-MICS, 2011) and 3.3% in Tchad (UNAIDS, 2012).

From these statistics, one can therefore argue that, like many other African countries, The Tchad continues to face the pandemic of HIV / AIDS. To significantly reduce the prevalence of this epidemic among the population, the authorities of this country prefer, as strategies, two types of approaches: a curative approach and the so-called preventive.

The curative approach is characterized by the search for a drug that taken by the HIV-positive or AIDS patient leads to its complete cure. Unfortunately, to date, although the curative approach known significant advances, it is clear that no drug can permanently cure the HIV-positive or patient with terminal phase of AIDS. To this must be added that the Tchad has no control over the curative approach, lack of resources and appropriate technology. Therefore, its authorities continue to emphasize the preventive approach. This involves educating the Tchadian population by raising awareness, that is to say by making available the appropriate information so that they can change their behavior.

Although the results are very encouraging, we must, however, take the appearance of a typical problem that goes far beyond medicine. This is the resistance to change behaviors as desired. The condom use refusal is in the logic of this resistance to change, especially among those might be called sex workers. This social layer, it must be said, is particularly affected by the epidemic as evidenced by the statistics in the countries of sub-saharan Africa, 80% (UNAIDS, 2013).

In Tchad, for example, according to UNAIDS (2012), the HIV status of sex workers involves more than one because of the prevalence of HIV/AIDS which is 20%. However, this percentage represents only the visible dimension of the iceberg because of the prevalence of illiteracy, stigma and discrimination continue to face sex workers. So despite the intensification of campaigns to prevent HIV/AIDS, it is likely that the results of the strategies of communication for behavior change are still insufficient and need further studies be intensified to reduce this fault phenomenon able to master it.

Thus leading this study, we intend to contribute to improving the state of knowledge of the factors explaining sexual risk behaviors among sex trade. This objective is justified, socially, by the fact that HIV / AIDS today called the "disease of the century", is timely and spares no social layer. Its dramatic consequences in terms of loss of life and increasing the number of orphans, widowers, widows, social event of brief leave indifferent. Therefore, the findings of this research could help policymakers and other development partners to have reliable information that can serve as a basis for management of specific sex workers needs. From there, they will integrate the issue of HIV / AIDS policies and national development programs.

Scientifically, sexuality is an area that has long attracted the attention of sociologists, psychologists, anthropologists and demographers. This attention stems, among others, the relationships identified between sexual behavior and certain phenomena with social, health, economic and adverse demographic. The proliferation of scientific works, globally, to identify the determinants of the pandemic is a potential indicator of worrying proportions within human societies. This written proliferation is also in the perspective of finding appropriate solutions to this epidemic. This course involves identifying its causes at a general level, specifically in terms of resistance to condom use. Precisely, in this way, agree to say that the listed causes are multiples. However, a literature review allows to identify four factors that explain groups. This is the socio-economic approach, socio-cultural, institutional and psychological.

The socio-economic approach considers youth as rational actors. This approach is based on the theory of "rational adaptation" that young people would engage in sex to achieve specific objectives, specifically economic or social order (Rwenge 1999). In the first case, one can note the studies insisted that economic conditions also contribute to youth engagement in sexual activity. Thus, the satisfaction of sexual impulses can be done in young boys in exchange for gifts, clothes, money or paid work for young girls. In the second case, find themselves studies that explain the sexual activity of young people, especially girls, marriage and fertility, it is actually a culmination of marriage strategy.

The socio-economic approach then states that the sexual activity of teenagers meets specific goals of economic and social order. Young boys and girls contract the sex for profit. This is the gender marketing phenomenon by teenage girls who want to earn money to meet their needs (Rwenge 1999). Worldwide, the lower economic and social status for women has the direct consequence of increasing their vulnerability to HIV and limit their ability to control their sex lives and protect themselves (Panos, 1993). In most African societies, gender relations are characterized by a power imbalance. In these societies, the role of women is essentially to have children and to exercise housework. Very few women have access to economic and educational resources crucial: information, assets, professional competence. Women's dependence on men has a negative influence on their ability to determine the conditions under which sex takes place.

According to this approach, young people living in poverty or at risk of poverty are vulnerable to sexual exploitation and are encouraged to exchange sexual favors to survive. Economic difficulties thus motivate adolescents to adopt behaviors "at risk". Under these conditions, some even engage in prostitution.

Noumbissie (2004) reveals, for example, that, in the metropolis, the sexuality is an economic variable and real currency. Feyisetan and Bankole (1991) and Meekers (1995), in the same direction, say premarital sexuality youth is both an economic objective and social objective. The purpose of sexual activity can also be fertility. This is usually a necessary strategy at the culmination of marriage. Therefore, it exposes girls to unprotected sex and suddenly promotes resistance to sexual behavior change and HIV/AIDS.

The socio-cultural approach is based on the fact that we can not "desocialize" sexual activity. It grants a central role in the social and cultural construction, without which, it claims, no desire can appear and speak (Foucault, 1984 quoted by Bozon, 1994b). Thus, the authors of this approach, sexual behavior are determined by socio-cultural norms and values about sexuality. That is all of these ideological constructions that determine the circumstances of the progress of sexual activity. In this case, sex would be spontaneous and do not meet a particular goal (Diop, 1995; Calvès 1996). One expression of this approach is the notion that sexual activity of young people in urban areas can be explained by the "social disorganization", the weakness of social control or loosening of morals. This thesis is part of the general theory of modernization, which is based on the weakening of traditional structures and loosening control on older cadets. The new resulting behaviors are more oriented towards personal satisfaction and personal gratification to family responsibility (Diop, 1995).

This approach requires that the weakening of traditional structures and the relaxation of the biggest checks on smaller from modernization would be the basis of sexual risk behaviors of adolescents (Sala-Diakanda 1980; Evina 1990). It is this factor that was favorable to the spread of sexually transmitted diseases (STDs) sterilizing (gonorrhea, gonorrhea, chlamydia and mycoplasma) or abortion (syphilis) (Sala-Diakanda 1980; Evina, 1990).

The institutional approach implies that sexual activity of young people in urban areas would also be based on the importance that policymakers attach to legislation and programs concerning them. Hence the emphasis on laws relating to marriage, to the marital life of parents, social protection of young people and the specific services to youth in some previous studies that have addressed this issue. The use of institutional factors for explanation of adolescent sexual behavior stems from the fact that policies create conditions likely to influence the behaviors of adolescents, their knowledge and sensitization to HIV / AIDS.

In most previous studies, these factors were presented as recommendations (Rwenge 1999). None of them has so emphasized their associations with the sexual behavior of young people. The celebration of youth unions is regulated in most African countries by texts on the organization of civil status and various provisions relating to the status of natural persons (Mbarga, 1991). There are however still African countries where child marriage legislation is non-existent; the "customary" and remains the legal framework for excellence in marriage (Rwenge 1999). This author also points out that there are laws on social protection of children, but very few African countries have and where these laws exist, they are rarely enforced. Population programs of African countries are limited in that they are more for adults and less young.

In the psychological approach, Campbell (1997) shows that among clients of sex workers, male identity is the basis of their refusal to use condoms during sex. Authors agree to discuss "internal factor" which consists of the difficulty experienced by some customers to control their sexual desires. This internal factor is mentioned as a potential barrier to the use of condoms with a sex worker. This difficulty controlling their sexual desires in fact corresponds to a male norm they have learned. Personal reluctance to use condoms are also explained by the fact that the users believe that they undermine the sensitivity, they cause discomfort or embarrassment when spontaneous relationships.

Furthermore, based on the conclusions of their study, Ku et al. (1993) show that young’s sex education change their sexual behavior, to the extent that sex education may delay the time of first sexual act, reducing the number of partners and increased condom use. But the loosening of social control sexual matters due to urbanization, western education and changes in production patterns in African societies has, indeed, led the young’s to adhere to certain western practices, including sexual libertinism (Bauni, 1990; Meekers, 1992).

From the literature review that has been made, we can argue that the refusal of condom use among individuals is due to several approaches. However, as part of our research, we focus on the psychological approach, including socio-cognitive aspects of the phenomenon: the perception of the social marketing of condoms and level of education individuals.

The choice of these variables is the fact that, for the psychologist, the problem of behavior change can be explained by the perception of messages calling for change, hence the inclusion of the perception variable. The latter, as a perceptual process, also depends on the level of education, that is to say the body of knowledge that the individual capitalized along its curriculum and/or academic and influences his opinion in respect of a given reality.

This rationale is supported by ecological theory of social cognition Beauvois (1995). This occurs in the overcoming of the classical theories of social perception that design perception as a process under the criterion of truth or accuracy. The special feature of this theory is that perception apprehends as evaluating the object according to the constraints of the environment.

According Beauvois (1995) perceive an object is to judge its value, that is to say, its desirability or social utility. The desirability refers to the emotions and motivations that a person can feel towards an object. Social utility refers to the social that is to say that, in a society, is a fundamental principle of evaluation.

This author, to build his theory has used the concept of affordance initially developed by Gibson (1966). The latter defines the affordance as what the environment offers a living being, he provides it for his own good or evil. The affordance is an offer of the environment, what it offers us for our good and our bad. This is the behavior that the environment makes it possible.

In this study, the use or not the object (here the condom) by sex workers implementing a set of behavior that previously considers the assessment they make of this object. This assessment is based of course on the affordances (A1: mean of prevention and protection against the epidemic...; A2: barrier to sexual pleasure element likely to put customers...). Finally, this is a result of this evaluation, which also takes into account their level of education they decide to behave vis-a-vis the social object.

This theoretical model that helps us make sense of our knowledge and strengthen our seen finally allows us to develop two working hypotheses below provide:

1. The condom social marketing perception has significant influence on condom use resistance among sex workers.

2. The level of education of professional sex workers greatly influences their resistance vis-a-vis of the condom during sex.

To submit to the test of reality these assumptions, he said seems to us to expose the appropriate methodological approach.

2. Methodology

Two types of variables are involved in this study. These are two independent variables and one dependent variable. The firsts concerns the perception of condom social marketing and educational level and the second represent the resistance to condom use.

The perception of condom social marketing refers to all cognitions relating to the social utility of condom. In other terms, it refers to the beliefs, ideas, the mental image developed by the sex professionals vis-a-vis of condom. Qualitatively, this variable has two distinct modes: positive perception and negative perception of the social marketing of condom. When the messages of social marketing concerning the condom are perceived as beneficial by the female sex workers, the perception is, in this case, positive. On the contrary, when the messages of social marketing around of condom are deemed harmful by the female sex workers, the perception is described as negative.

The level of education is considered as the most educational level attainment of sex workers. This variable is qualitative and has two characters, first level and second level. The first level takes into account the sex workers whose educational level is limited to the first secondary school (from primary to the last level of the first secondary school). The second level, meanwhile, includes sex workers with a higher level of education in lower secondary education (from second grade and higher).

The resistance is a polysemic concept that relates to the context to which it uses. However, in this study, should be considered resistance to condom use facing the HIV/AIDS as a set of overt behaviors both offensives and defensives opposing the use of condom. It is a qualitative variable with two modalities: low and high resistance to condom use. Low resistance to condom reflects the situation where the sex worker uses quite often the use of condoms during his sexual acts with its customers. In contrast, is called strong resistance to condom using any situation where the sex worker uses rarely use condoms during sexual acts with its clients.

The study population is all sex workers in N'Djamena. According AMASOT (2013), the prevalence of infection with HIV/AIDS in this city amounts to 25.5%.

However, since it is impossible to question all sex workers of that city, statistical methods allow us to select the subjects of a given study. This process is called sampling. As part of this research, in the absence of a database on subjects of study, we used simple random sampling. In principle, each member of a population has an equal chance of being included within the sample. Each combination of members of the public also has an equal chance to compose the sample. The simple random method is the easiest sampling method to apply and the most commonly used. The advantage of this technique is that it requires no additional data in the frame (like geographic region) other than the complete list of members of the surveyed population and information to contact them.

Also, as simple random sampling is a simple method and the theory behind it is well established, there are standard formulas for determining the sample size, estimates, etc., and these formulas are easy to use. Finally, with this technique, one hundred (100) Professional sex workers were selected.

They have an age ranging from 20 to 24 years, because this age group is the most affected by the epidemic with a prevalence rate of 22% (AMASOT, op.cit.). They come from seven (07) districts identified as the main areas where prostitution is practiced (UNAIDS, 2013). These are areas of Moursal, Kaballay, Ambassatna, Djambalbare, Chagoua, Nguéli and Bololo. In some of these areas, it indicates the presence of a particular market called "Mokolo market" and several inns where meet many professional sex at nightfall.

The selected respondents were submitted to a questionnaire during an investigation. This lasted a month and was performed by indirect administration because of the delicacy of the subject of study. Once appropriate to have the culture of our target population, we relied on their leaders and some of their members they have in our disposal to administer our investigative tool.

It should be noted that the questionnaire has three axes. The first line contains the demographic characteristics of the respondents (age, ethnicity, religion, marital status, socioeconomic status). The second area includes statements concerning the perception of condom social marketing. Five in number (05), these statements were developed from indicators on the affordances of condoms. The subject must choose between true and false. The third axis consists of questions about the use of condoms during sexual intercourse. Specifically, the subject must indicate the frequency of condom use during his passes by checking either never, rarely, often or always.

With this survey, we were finally able to collect data which subsequently underwent statistical processing. This treatment, two different types of results is recorded. They are thus presented.

3. Results

The results of this study stem from existing working hypotheses. They occur in two forms.

1. Perception of condom social marketing and resistance to condom use

To test the significance of this first independent variable on the phenomenon under study (resistance to condom use), we used the statistical test of chi-squared. This test is applied to the following table:

Table 1. Frequencies distribution of the sex professionals according to the perception of condom social marketing

The chi-squared calculated using the SPAD software is 5.63. This value is well above the chi-squared read (3.84) at the 0.05 probability level and one degree of freedom. The difference is therefore significant that threshold. Moreover, a detailed examination of comparative frequencies illuminates the significant difference observed. It reveals that the majority of sex workers having a negative perception of the social marketing of condom showed a strong resistance to wearing such protection mean (28 on 46, or 60.87%) in contrast to a minority of positive perception and a strong resistance to concerning the condom use (20 on 54 or 37.03%). Conversely, the majority of sex workers who have a positive perception of condom weakly resist using it (34 on 54, or 62.96%) in contrast to a minority of them a negative perception and a low resistance (18 on 46, or 39.13%).

Hypothesis 1 is thus confirmed. Sex workers who have a negative perception of condom social marketing are highly resistant to the port of it during the sexual act than their counterparts who have a positive perception.

This result can be explained by several reasons. First, the observed resistance among sex workers vis-a-vis to the port of condom may be due to the reflection of the thought patterns of social group to which they belong. What fantasies and misconceptions hear these girls about condoms and sexuality as they have adult with them? The resignation of parents and the community that no longer fulfill their role is to give good sex education to girls forcing them to turn to their peers. Now, the bad influence the peers lead some of them to be encouraged by others to take risks in their sexual relationships. This risk taking is also enhanced by the economic poverty that forces them to seek and have money often paying with their live.

Next, it should be emphasized that AIDS poses not only a physical and mental health problems or psychological but especially sexual behavior problem that takes place in a context of social pressures. Therefore, integration of condom in sexual practices of female sex workers involves significant changes in their sexual habits. These changes are upsetting or disturbing their equilibrium can only generate the resistances. Indeed, the condom generates, psychologically, in the past, perceptions, representations, motivations and attitudes that lead to just the resistance.

In light of the ecological approach of social cognition, such resistance is explained by the fact that the affordances from which the social object (condom) is evaluated are perceived as providing less scope for action to sex professionals. So, based on this perception, all the messages around this object or mean of protection have not systematically internalized in their psychological functioning and therefore in their sexual relationships.

Finally, the non-use of condom among the female sex workers is supported by certain religious beliefs and cultural norms that restrict or stigmatize the condoms use. Do not ignore that the Tchad is a country with large Muslim dominance. From the point of view of this religion, the use of condoms is seen as a practical little "manly", especially when ejaculation within the vagina is considered a key moment of the sexual relationship. Marked by this religious and cultural education, do not be surprised to see such opposition with regard to condom use among the women in general and particularly the female sex workers.

In addition, another possible explanation lies in the fact that sex workers are often unable to negotiate the use of condom. These are usually the brothel keepers and pimps who decide whether to use condoms by sex workers and their clients.

2. Level of education and resistance to condom

The chi-squared is best described here to test the effect of the second explanatory variable on the dependent variable of the study: resistance to condom use. On the table below is applied:

Table 2. Frequencies distribution of the sex professionals by the level of education

14.59 is the value given by the chi-squared calculated. Compared to read chi-squared (3.84), whichever is greater, that the 0.05 probability level and one degree of freedom. Careful analysis of the compared frequencies can account for this difference. It indicates that the majority of subjects who have a lower level of study at first secondary school show a strong resistance to condom (38 on 60, or 63.33%) against a minority of a higher educational level at first secondary school and a high resistance (10 on 40, 25%). Conversely, the female sex workers of level of study higher at first secondary school have a low resistance vis-a-vis the condom (30 on 40, 75%) against a minority of them with a lower level of study at first secondary school with a low resistance (22 on 60, or 36.67%).

We conclude with a confirmation of the hypothesis 2. Thus, female sex workers with a level of study is limited to the first secondary school show a strong resistance vis-a-vis of condom port during the sexual relationship than their comrades of a level of education higher than at first secondary school.

This result is understandable in view of the importance of education in the life of a person. Indeed, one of the major roles of schooling is to provide the individual a body of knowledge’s. These, in turn, allow him to better appreciate the different facts of the society, treat fairly the various informations of the environment to adopt appropriate behaviors. The subject sufficiently educated is more likely to have a wide view (contours and edges) messages provided by the social environment and, therefore, more likely to get it right before the situations or problems of life. Is that the instruction received made him a freed person, thoughtful and vigilant. But, the more an individual goes far in his studies, the more it acquires and accumulates intellectual knowledge’s, expertise and knowledge be greatly guided his actions.

Cognitively, it shows greater ease in processing information and giving them a meaning. Moreover, the intellectual potential it has, through everything he has learned in his studies, may make him a less suggestible about his group of friends. Where else would lack arguments to support an idea (here the benefits of condom use), he will defend his point of view or position. Then explains that the female sex workers who have a level of education higher at first secondary school weakly resist condom they know the benefits or positive aspects in the fight against HIV/AIDS.

In contrast, the sex professionals of level of study lower at first secondary school are, intellectually, somewhat limited. So in front of some aspects of social life, they may have difficulty understanding the validity of certain actions. Inadequate acquired knowledge or ignorance of certain things of life may expose them to danger. This is especially true, because ignorance is the mother of all vices. An unprotected sexual relationship is one.

4. Discussion

This study was conducted in order to highlight some of the determinants of resistance to condom use among the female sex professionals. When we are heading, it should be noted both accomplished tow conclusions.

The first reveals that the female sex workers who have a negative perception of condom social marketing are highly resistant to the port of it during the sexual relationships than their counterparts who have a positive perception. This result is congruent with the works of Numbi (2007). He said several reasons explain the non-use of condom, including difficulties to understand and explain the prevention messages. These challenges include the inability to identify difficult words, signs, foreign and unusual codes in Zaïre environment. The refusal to wear a condom also depends on a wrong selection times and places of communication around this mean of protection and prevention.

For his part, an Amadou (2008) show that the non-condom uses among the young Nigerians is significantly related to their ethnicity. Note that the term ethnicity has indicator socialization, area of residence. He argues that adolescents belonging to an ethnic group advocating permissive mores have early sex with casual partners without condoms.

The second indicates that the female sex workers have a level of study limited to the first secondary school show a strong resistance vis-a-vis to the port of condom during the sexual relationship than their peers of a higher level of education to the first secondary school. This result converges with those reported by Lagarde et al. (2001). These authors show that a low level of education appears to be a risk factor. They argue that the female sex workers little or no education were more likely than their friends from secondary/higher grade. They explain this fact by limited access to sex professionals with little education to information and education on the HIV/AIDS. Say definitively that their study shows that educational attainment is associated with certain risky sexual behaviors, including those that are practiced without condom.

Rwengé (1999; 2000) and Kouton (1992), meanwhile, show that the level of education significantly influences the early occurrence of sexual debut means that an advanced education correspond to lower risks of early sexual activity. Kuate-Defo (1998) highlights the reducing effect of improving women's education on early sexual activity in Cameroon. In Benin, Kouton (1992) observed that over the teenager with the high school, the teenager who has at most primary level has 7 times more likely to have early sex.

Almost in this perspective, Bédard (2005) asserts that the girls who are perceived as having no experience or with little experience are those that some men, thanks to their power, influence easily for the sexual relationships without protected. According to this author, in this context, the girls appear in the eyes of these men and women-objects.

The findings of this research are on the practice range at two levels. First, they help to deepen the examination of complex psychological determinants of resistance to condom use. Secondly, by now including these two variables in the explanation and understanding of resistance to condom use, one could anticipate the occurrence of this phenomenon by acting upstream of these identified factors. We believe that quality promotional message can help make condoms not only acceptable but also representative of a modern and responsible attitude in the sex professionals. They will thus become more attractive because it is important to clarify that any action at the location of that corporation must be based on facts and not assumed. It also implies the need to clarify first of all how female sex workers perceive condom social marketing. This research is realistic and can provide an illuminating approach to the issue of condom use by sex workers in N'djamena.

To boost motivation and break brakes, awareness messages, according to the methods of interpersonal communication, must be differentiated, clear, appropriate to the context middle and psycho borrow easily accessible channels. Efforts in the field of education must also aim to lift the stigma that weighs on the use of condoms, to make this normal and acceptable attitude. Similarly, many religious and social barriers must be overcome.

This study, although interesting, nevertheless presents some methodological shortcomings. First, the sensitivity of the subject forced us to investigate by proxy (the responsible professional sex). Therefore, the answers given by the respondents could be concealed. Then simple random sampling used here allows us to generalize the results of this study because of not being representative of the population. Finally, the questionnaire may not allow to identify the complexity of the phenomenon.

As a result of the above, we recommend that this study extends not only a sample of a larger size but also that the measuring instrument is complemented by a directive or semi-structured interview.