INTRODUCTION
Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are serious global public health problems. It is estimated that there are 350 and 130 million chronic carriers of these viruses, respectively, which are also at risk of developing chronic hepatitis, cirrhosis, and hepatocellular carcinoma1,2.
Hepatitis B virus has been classified into eight genotypes (A-H)3, and six HCV genotypes (1-6) and multiple subtypes have already been described4. The genotypic groups have variable geographic distribution and have been used to trace transmission routes. Furthermore, the genetic diversity of these viruses seems to interfere in the effectiveness of antiviral treatment5,6.
The prison population is at high risk for acquiring infectious diseases such as hepatitis B and C. Further some investigations have identified these viruses as important causes of deaths related to chronic liver diseases in prisoners7,8. Many characteristics of confined people, including low socioeconomic status, illicit drug use, and multiple sexual partners, are predictors of these infections. Therefore, most are already infected at the time of imprisonment, becoming a source of propagation and maintenance of these viruses in the prison setting9-11.
The majority of studies on HBV and HCV infections in the prison population have been carried out among male prisoners12-14. As such, the overall results of these studies generally reflect the characteristics of the dominant population. In Brazil, a continental country, the few available data on hepatitis B and C epidemiology in female prisoners are mainly from populations in the Southeast Region10,11,15. Thus, the purpose of this study was to investigate the prevalence and risk factors associated with HBV and HCV infections and to identify the genotypes of these viruses circulating in female prisoners of Goiás, Central Brazil.
METHODS
This was a cross-sectional study of the female population serving time in the Complexo Prisional of Aparecida de Goiânia, which represents the largest prison complex in the State of Goiás, Central Brazil16. From August 2007 to June 2008, all of the female inmates (n=150) were invited to participate in the study; two refused to participate. Written informed consent was obtained from all 148 women who agreed to participate. The study was approved by the Ethics Committee of the Federal University of Goiás (Protocol Number: 074/06).
Participants were interviewed face to face on sociodemographic data and risk factors. After the interview, a blood sample was collected by venipuncture and tested by enzyme linked immunosorbent assay (ELISA) for detection of hepatitis B surface antigen (HBsAg), antibody to hepatitis B surface antigen (anti-HBs), antibody to hepatitis B core antigen (anti-HBc) (Hepanostika Uni-form Biomérieux, Netherlands), and hepatitis C virus antibody (anti-HCV) antibodies (Abbott Laboratories, Brazil). Samples weakly reactive to anti-HCV (ratio OD/cut-off <3.0) were retested by line immunoassay (INNO-LIA HCV Ab III, Innogenetics , Belgium).
Deoxyribonucleic acid (DNA) was extracted from HBsAg-positive samples, and the Pre-S/S genome region was amplified using a semi-nested PCR assay17. Polymerase chain reaction (PCR) products were subjected to restriction fragment length polymorphism (RFLP) genotyping analysis18. The detection of viral ribonucleic acid (RNA) was carried out in all anti-HCV-positive samples by reverse transcription polymerase chain reaction (RT-PCR), using primers complementary to the 5′ non-coding region of the HCV genome19. The hepatitis C virus ribonucleic acid (HCV RNA)-positive samples were genotyped using a line probe assay (INNO-LiPA, Innogenetics, Belgium).
The HBV and HCV prevalence was estimated using a 95% confidence interval (95% CI). Initially, bivariate analysis was performed to determine the relation between the dependent variable (prevalence of HCV or HBV) and each independent variable, thus obtaining the prevalence ratios and respective confidence intervals of 95%. Variables with value p < 0.10 were included in the multivariate Poisson regression models. All analysis were performed using the Stata statistical Package v. 11.
RESULTS
The majority of female prisoners was ≤ 30 years of age (60.1%), had five-to-nine years of formal education (52.9%) and reported a family income of less than or equal to one Brazilian minimum wage salary per month (65.2%). Within the study population, 63% were born in Goiás and the remaining (37%) were born in other Brazilian states. Approximately half of the participants (46.6%) were married, 36.5% were single, and 16.9% were divorced/widowed.
As shown in Table 1, 28 (18.9%) women were anti-HBc positive: 25 (16.9%) had anti-HBc associated with anti-HBs, and 1 (0.7%) had anti-HBc associated with HBsAg. Only 36 (24.3%) women were positive for anti-HBs alone, suggesting previous vaccination against hepatitis B. Further nine inmates (6.1%; 95% CI: 3.0-11.6) were anti-HCV positive by ELISA and were confirmed by immunoblot.
95% CI: 95% confidence interval; HBV: hepatitis B virus; HCV: hepatitis C virus; HBsAg: hepatitis B surface antigen; anti-HBc: antibody to hepatitis B core antigen; anti-HBs: antibody to hepatitis B surface antigen; anti-HCV: Hepatitis C virus antibody
Hepatitis B virus deoxyribonucleic acid (HBV DNA) was detected in the HBsAg positive sample, and genotype A was identified. HCV RNA was detected in five samples. Genotyping revealed the presence of genotype 1, subtypes 1a (n = 3) and 1b (n = 1), and genotype 3, subtype 3a (n = 1).
The 36 female prisoners positive for anti-HBs alone were excluded from the analysis of risk factors for HBV infection. Age over 30 years, lower education, injection drug use, sexually transmitted disease (STD) history, sex with an STD carrier and sex with a drug user were statistically associated with HBV infection (p <0.05) (Table 2). In addition to sex with a male prisoner (p=0.10), these variables were included in a multivariate Poisson regression model, and four were independently associated with HBV infection: age > 30 years, lower education, sex with an STD carrier, and sex with a male prisoner (Table 3).
95% CI: 95% confidence interval; PR: prevalence ratio; HBV: hepatitis B virus; HCV: hepatitis C virus; STD: sexually transmitted diseases; IDU: Injection drug use. a denominators reflects the number of valid responses.
PR: prevalence Ratio; 95% CI: 95% confidence interval; HBV: hepatitis B virus; HCV: hepatitis C virus; STD: sexually transmitted diseases; IDU: Injection drug use; a adjusted Prevalence Ratio by age, schooling, IDU, STD, Sex with STD carrier, sex with IDU and sex with male prisoner; b adjusted Prevalence Ratio by age, illicit drug user, IDU, sex with IDU, length of incarceration, and number of prisons.
With regard to HCV infection, the following variables were statistically significant: age over 40 years, injection drug use, having sex with a drug user, and the number of prisons attended (p < 0.05) (Table 2). In addition to illicit drug use (p = 0.09) and length of incarceration (p=0.07), these variables were included in a multivariate Poisson regression model. Age over 40 years, injection drug use and length of incarceration were independently associated with HCV infection (Table 3).
DISCUSSION
The present investigation confirms that female prisoners have a high risk for hepatitis B and C infections. Seropositivity for HBV markers in our study (18.9%) was three fold higher than that found in a female population aged 13 to 69 years in the Midwest Region of Brazil (6.6%)20. Further, the present prevalence was higher than that found in female prisoners in São Paulo (n=225; 8.4%; 95% CI: 5.3-13.0)15 but was similar to those reported by Stief et al.21 in Mato Grosso do Sul (n=242; 14%; 95% CI: 10-19.2) and in other countries such as England (n=400; 12.2%; 95% CI: 9.3-16)22, and the United States of America (n=555; 26%; 95% CI: 24-27)23.
Although our study demonstrated that prevalence of hepatitis C among inmates (6.1%) was 40-fold higher than that reported in pregnant women in Goiânia City (0.15%)24, but it was lower than those recorded by Strazza et al.11 (n=290; 16.2%; 95% CI: 12.3-21.1) and Miranda et al.10 (n=121; 19%; 95% CI: 12.7-27.3) among female prisoners in southeastern Brazil and in other countries such as Italy (n = 973; 38%; 95% CI: 34.9-41.2)13, England (n= 9965; 24.2%; CI 95%: 23.4-25.1)25, Finland (n= 388; 52%; 95% CI: 46.9-57.1)26 and Australia (n=630; 57.5%, 95% CI: 53.5-61.3)27.
Five of the nine anti-HCV-positive samples were also HCV RNA positive. These samples were genotyped as genotype 1, subtypes 1a (n = 3) and 1b (n = 1), and genotype 3, subtype 3a (n = 1). Similarly, another study conducted in male prisoners from the same penitentiary complex found genotype 1 in 80% of the samples (1a = 60%), followed by genotype 3a (13.3%) 28. In this sense, the HCV genotypes circulating in Goiás prisoners reflect the diversity of this virus in Goiás, Central Brazil29,30.
As observed elsewhere21,23,24, age was independently associated with HBV and HCV infections. In this investigation, the age association was evident among women > 30 years old for hepatitis B, while HCV infection increased after age 40.
Hepatitis B virus is efficiently transmitted by sexual contact, while HCV is spread predominantly by parental routes1,2,31. The present findings highlight these assumptions. There was a significant association between HBV markers and sexual variables, including sex with an STD carrier (adjusted PR: 3.0) and sex with a male serving time in the same penitentiary (adjusted PR: 2.3). By contrast, illicit injection drug use was a predictor of HCV infection (adjusted PR: 5.9), suggesting parenteral transmission of this virus.
Outbreaks of viral hepatitis are not unusual events in prisons32-34. In this investigation, one female prisoner was HBsAg and HBV-DNA positive, and five were HCV RNA positive. These individuals may serve as reservoirs of HBV and HCV and may be potential transmitters of these viruses in the prison environment and their social network. In fact, a stricter association was found between HCV positivity and length of incarceration.
Although the hepatitis B vaccine has been recommended for prisoners since it became available in the 1980s35, a low immunization rate is still observed in this group36. In Brazil, this vaccine has been recommended and free of charge for prisoners since the late 1990s. Nonetheless, only a low frequency of individuals vaccinated against hepatitis B has been observed. In Rio Claro (southern region) and Campo Grande (midwestern region), serologic evidence of previous vaccination was found in only 13.8% and 32.3% of the prisoners investigated, respectively15,21. Our investigation indicated a similar rate, as only 24% of the women were anti-HBs positive alone, suggesting previous vaccination against HBV.
Our results should be considered with caution. This was a cross-sectional study, and behavioral findings are based on self-reports. Although this study included 98.6% (148/150) of the female inmates of the largest prison Complex in State of Goiás, Central Brazil, they may not be representative of all women confined in this state.
Prisoners should be targeted for hepatitis B and C prevention and control programs. Serological screening at the time of admission and treatment of those with chronic hepatitis may contribute to the reduction of such infections in Brazilian prison settings. A safe and effective hepatitis B vaccine is available free of charge for this population, and investigations have reported a good acceptance of this vaccine among prisoners37. Therefore, the low HBV vaccination rate in this population should indicate that there is a need for interventions aimed at improving hepatitis B vaccination in prison settings.