The present study is the first epidemiological study of the seroprevalence of HSV-2 in prisoners at penal establishments of Brazil and associated risk factors.
Our results have several important implications for public health. First, the overall prevalence of HSV-2 infection was 43.1%, almost four-times higher than the global prevalence (11.3%;(16, 20), and also higher than the prevalence in the general population of Brazil (about 30%; (21). The prevalence of HSV-2 infection in this study was also higher than reported in previous studies of prisoners elsewhere in the world. For example, the seroprevalence was 20.5% at prisons in northern Italy, 21.3% at prisons in southern Italy (22), 19.9% in a cross-sectional regional level study of prisons in Portugal (23), and 14.5% at prisons in Nigeria (24).
The higher prevalence of HSV-2 infection in Brazil may be due to the ineffectiveness of its prison organization, in which incarceration can directly and indirectly cause adverse health effects (3).
Due to the greater number of male samples, the prevalence in men was higher than in women (32.1% and 11%, respectively). However, we also found that the estimated Seropositivity rate of HSV-2 infection was 68% among women and 37% among men. In statistical analysis indicated the prevalence was 3.4-fold greater in women in adjusted model. A similar study in Australia (25) also reported that women had a higher seroprevalence for HSV-2 than men. This may be because the signs and symptoms in women occur in the vaginal mucosa, and therefore tend to be less visible (26, 27); (28). In addition, the sexual transmission of herpes from men to women is much more efficient than the transmission from women to men (12, 29, 30). In pregnant women, HSV-2 can be transmitted to the fetus during pregnancy and/or parturition (26, 27).
Our results indicated that the risk for HSV-2 increased with older. This may be because those who are older simply have more years during which they could possibly be exposed.
These results indicated that prisoners who already had another STI had a nearly 5-fold increased risk of HSV-2 positivity. A 2017 study by our group found that the prevalence of HSV-2 in HIV-positive pregnant women was 3-fold greater than the prevalence of HIV-negative pregnant women (31). HSV-2 infections have been identified as a risk factor for contracting STIs mostly HIV, especially in the presence of a lesion, even if it is not apparent, since the lesion would serve as a gateway to the other STIs.
The present study also showed that prisoners who were not previously incarcerated had an increased risk of HSV-2 positivity relative to those who were previously incarcerated; and that the presence of 26 or more other prisoners in the same room increased the risk of HSV-2 positivity. Although the current legislation represents an advance in the guarantee health of the population incarcerated in Brazil, it is known that the conditions unhealthy incarceration such as: overcrowding, space for the dissemination of diseases and exposure to violence, associated with the lack of structure to carry out of health care in the prison environment such as: space, reduced number of health professionals, untrained professionals to deal with the specificities of the prison population, as well as tensions among inmates themselves, make it difficult to carry out promotion and protecting the health of this population. In Brazil, the rate of prison overcrowding is 166% (32)
None of our study participants reported apparent lesions from HSV-2 infections, however the presence of genital discharge in the last month increased the risk for HSV-2 positivity, even though HSV-2 infection is typically characterized by no apparent signs or symptoms. The most common symptoms of infection are vaginal discharge and/or discomfort during sexual relations (33). Contact with ulcerated lesions or vesicles is the most common route, but transmission can also occur through the asymptomatically.
Although our prisoners reported a low frequency of homosexual intercourse (7.9%), individuals who did have homosexual intercourse had an increased risk of HSV-2 positivity. Many previous studies have examined HSV-2 in populations of men who have sex with men. The results indicated a high prevalence in this population, thus demonstrating the importance of implementing prevention programs that target these high-risk groups (34); (35); (36); (37).
When an individual contracts herpes, the immune system develops IgG and IgM. IgM generally detectable 9 to 10 days after exposure to the virus and last 7 to 14 days, although they can remain detectable for up to six weeks under certain criteria. It is always important to evaluate IgM since positive individuals are more likely to transmit HSV-2 and outbreaks can be identified (38). The presence of anti-HSV-2 IgM was detected in 46% of prisoners who were anti-HSV-2 IgG-positive. However, the presence of this IgM does not necessarily suggest a primary infection, because reactivation of a latent infection may lead to anti-HSV-2 IgM positivity (38). We also found that the presence of more prisoners in the same cell (<26 vs. 26 to 50) is associated with an increased risk of active HSV-2 infection. This is likely because overcrowding increases contact among prisoners, and is also associated with more intimate contact and worse hygiene.
Conflict in the prison environment can adversely impact the health of prisoners, contributing to the spread of multiple STIs as HSV-2, due to the emotional stress suffered in the prison environment (8).
Interventions and improvements in the provision of basic health care to prison population worldwide are needed, such as screening of individuals infected with STIs, Interaction between prisoners and health services, medications and effective treatment and health care and hygiene (39)
In cases of individuals identified with any STI, including HSV-2, we suggest as an intervention the temporary suspension of intimate visits, large-scale distribution of condoms, treatment and talks on the prevention of STIs. The virus dissemination can occurs due to the mobility into and out of prisons, with about 30 million people transiting each year worldwide there is also great mobility within individual prisons, due to transfers among different units, and the return of former prisoners who committed subsequent crimes (40). Thus, the high rate of HSV-2 infection at prisons in Brazil may have a significant economic impact on Brazilian society at large. (41, 42). Infected individuals can experience frequent relapses. In addition, this disease is associated with an increased risk of transmission of other STIs, including HIV. In Brazil, treatment for STIs is performed by Unified Health System (SUS) and has a high cost for public coffers. it is worth mentioning that the WHO has since generated estimates to assess the global burden of STIs and help respond to partner countries and institutions. This includes research to strengthen prevention, improve the quality of care, develop point-of-care diagnostics and new treatments, as well as generate investments in vaccine development (32)
This study had some limitations. First, the reported associations rely upon the veracity and memory of the study participants', especially regarding risky behaviors.