Hepatitis B virus DNA in blood donors with anti-HBc as a possible indicator of active hepatitis B virus infection in Yucatan, Mexico

Hepatitis B Virus Genotype H: Epidemiological, Molecular, and Clinical Characteristics in Mexico

The hepatitis B virus (HBV), comprising of ten genotypes (A-J), has been a silent threat against humanity, constituting a public health problem worldwide. In 2016, the World Health Organization set forth an impressive initiative for the global elimination of viral hepatitis by 2030. As the target date approaches, many nations, particularly in the Latin American region, face challenges in designing and implementing their respective elimination plan. This review aimed to portray the state of knowledge about the epidemiological, molecular, and clinical characteristics of HBV genotype H (HBV/H), endemic to Mexico. PubMed, Scopus, Web of Science, and Google Scholar were searched to compile scientific literature over 50 years (1970-2022). A total of 91 articles were organized into thematic categories, addressing essential aspects such as epidemiological data, risk factors, HBV genotype distribution, HBV mixed infections, clinical characteristics, and vaccination. The prevalence and its associated 95% confidence interval (95% CI) were estimated using the Metafor package in R programming language (version 4.1.2). We provide insights into the strengths and weaknesses in diagnostics and prevention measures that explain the current epidemiological profile of HBV/H. Training, research, and awareness actions are required to control HBV infections in Mexico. These actions should contribute to creating more specific clinical practice guides according to the region's characteristics. Mexico's elimination plan for HBV will require teamwork among the government health administration, researchers, physicians, specialists, and civil society advocates to overcome this task jointly.

Occult hepatitis B in kidney transplants recipients and donors from Western Mexico

BACKGROUND

Occult hepatitis B virus infection (OBI) is defined as the presence of hepatitis B virus (HBV) DNA in serum and/or liver from HBsAg-negative subjects. Our aim was to determine OBI frequency in serum and genomic DNA in patients undergoing renal transplant and their cognate donors in a selected population from Western Mexico.

METHODS

Blood samples were obtained from 94 donors and their cognate recipients (188 participants) before kidney transplantation. Identification of HBV DNA was carried-out by nested (S-region) and semi-nested (Pol-region) PCR in both genomic and serum DNA samples from 188 participants at pre-surgical stage and from a subset of 73 recipients at three-month follow-up.

RESULTS

HBV-DNA was not detected in either genomic or serum DNA samples from recipients or donors prior to transplantation. After three-months of follow-up, 2 out of 73 (2.7%, 95% CI: 0.9-11.9%) recipients were positive to HBV-DNA (Pol-region) in genomic DNA samples using a high sensitivity Taq DNA polymerase.

CONCLUSIONS

OBI incidence in recipients of kidney transplant may be higher than previously recognized. Detection of HBV-DNA was higher in genomic DNA than in serum samples using a high sensitivity Taq DNA polymerase. To the best of our knowledge, this is the first report regarding this specific topic in Mexicans.

Prevalence and risk factors of hepatitis B and C among hemodialysis patients in Tunisia

OBJECTIVE

Hemodialysis patients are at increased risk of infection by hepatitis C and B viruses, which are significant causes of mortality and morbidity. Prevention of their transmission in hemodialysis units remains a challenge worldwide. We aimed to investigate the prevalence of these two infections and to explore major risk factors among patients on chronic hemodialysis.

MATERIALS AND METHODS

We performed a cross-sectional study of 109 hemodialysis patients (mean duration of hemodialysis of seven years) between 2012 and 2014 in a Teaching Hospital of Monastir, Tunisia. Hepatitis B and C serological markers were searched for using a chemiluminescent assay. Genome detection was performed using a commercially available quantitative real-time PCR test.

RESULTS

A total of 109 hemodialysis patients were enrolled (75 males and 34 females). Ages ranged from 21 to 81 years. Six (5.5%) of these 109 patients had HBV infection defined by a positive HBsAg in four (3.7%) patients and by a detectable DNA associated with an "isolated anti-HBc" profile in the remaining two patients. Hepatitis C was observed in eight patients (7.3%) and five of them had detectable RNA. Hemodialysis duration ˃5years was the main risk factor for hepatitis C infection (P=0.01; OR: 3.11; 95% CI [1.57-13.71]).

CONCLUSION

Our findings confirm the downward trend of the prevalence of both hepatitis B and C infections among Tunisian hemodialysis patients. Hemodialysis duration remains the main risk factor for hepatitis C infection. Occult hepatitis B infection should be suspected and investigated, especially among patients with an "isolated anti-HBc" profile.

Isolated anti-HBc: The Relevance of Hepatitis B Core Antibody-A Review of New Issues

Hepatitis B core antibody (anti-HBc) is considered the most sensitive serological marker for history of hepatitis B virus (HBV) infection. In a subset of anti-HBc carriers, anti-HBc is present in the absence of hepatitis B surface antigen and hepatitis B surface antibody-a serological pattern known as "isolated anti-HBc" (IAHBc). IAHBc has been of clinical interest over the past several years, with growing data to suggest its role as a serological marker for occult HBV infection (OBI). This article reviews the clinical significance and association of IAHBc with hepatitis C virus (HCV) co-infection, risk of HBV reactivation during direct-acting antiviral therapy for HCV as well as immune suppression, and development of hepatocellular carcinoma (HCC). Hepatitis B core-related antigen is also highlighted as an emerging laboratory assay that may identify OBI and predict HCC development in non-cirrhotic patients receiving nucleoside/nucleotide analog therapy.

High prevalence of HBV infection, detection of subgenotypes F1b, A2, and D4, and differential risk factors among Mexican risk populations with low socioeconomic status

Hepatitis B virus (HBV) infection may be underestimated among high-risk individuals in regions of low HBs antigenemia. This study aimed to assess HBV serological markers, genotypes, and risk factors in Mexican patients with risk of HBV infection and low socioeconomic status. Demographics, clinical, and risk factor data were collected in patients with HIV (n = 289), HCV (n = 243), deferred blood donors (D-BD) (n = 83), and two native populations, Mixtecos (n = 57) and Purepechas (n = 44). HBV infection was assessed by HBsAg, anti-HBc, and HBV-DNA testing. Overall, patients had low education and very-low income. Totally, HBsAg prevalence was 16.5% (113/684) ranging from 0.7% (HCV) to 37.3% (D-BD), while anti-HBc was 30.2% (207/684). Among 52 sequences, genotypes H (n = 34, 65.4%), G (n = 4, 7.7%), subgenotypes F1b (n = 7, 13.5%), A2 (n = 6, 11.5%), and D4 (n = 1, 1.9%) were detected. Surgeries, sexual promiscuity, and blood transfusions had a differential pattern of distribution. In HCV patients, single (OR = 5.84, 95%Cl 1.91-17.80, P = 0.002), MSM (OR = 4.80, 95%Cl 0.75-30.56, P = 0.097), and IDU (OR = 2.93, 95%CI 1.058-8.09, P = 0.039) were predictors for HBV infection. While IDU (OR = 2.68, 95%CI 1.08-6.61, P = 0.033) and MSM (OR = 2.64, 95%CI 1.39-5.04, P = 0.003) were predictors in HIV patients. In this group, MSM was associated with HBsAg positivity (OR = 3.45, 95%CI 1.48-8.07, P = 0.004) and IDU with anti-HBc positivity (OR = 5.12, 95%CI 2.05-12.77, P < 0.001). In conclusion, testing with a combined approach of three different HBV markers, a high prevalence of HBV infection, a differential distribution of HBV genotypes, including subgenotypes F1b, A2, and D4, as well as risk factors in low-income Mexican risk groups were detected.

Prevalence of Serologic Hepatitis B Markers in Blood Donors From Puebla, Mexico: The Association of Relatively High Levels of Anti-Core Antibodies With the Detection of Surface Antigen and Genomic DNA

BACKGROUND

The hepatitis B virus (HBV) causes chronic hepatitis, hepatic cirrhosis, and hepatocellular carcinoma. Surface antigen (HBsAg) detection is a definitive test that can confirm HBV infection, while the presence of antibodies against the core protein (anti-HBc) suggests either a previous or ongoing infection or occult hepatitis B infection (OBI).

OBJECTIVES

The aim of the present study was to determine the prevalence of anti-HBc and HBsAg in blood donors. Further, the study aimed to estimate the anti-HBc level at which HBV DNA is detected in putative OBI cases, as well as to search for mutations in the "a" determinant associated with the non-detection of HBsAg in serum.

PATIENTS AND METHODS

We conducted a cross-sectional study from 2003-2009. The study included 120,552 blood donors from the state of Puebla, Mexico. Different commercial systems based on microparticles (enzymatic (MEIA) or chemiluminescent (CMIA)) were used to determine the HBsAg and anti-HBc levels. For the detection of HBV DNA, a nested polymerase chain reaction (nested PCR) was used and the genotypes were determined using Sanger sequencing.

RESULTS

Of the 120,552 blood donors, 1437 (1.19%, 95% CI: 1.12 - 1.26) were reactive to anti-HBc, while 82 (0.066%, 95% CI: 0.053 - 0.079) were reactive to HBsAg. Some 156 plasma samples collected in 2009 from anti-HBc-positive/HBsAg-negative blood donors were submitted for HBV DNA detection in a search for probable OBI. Viral DNA was detected in 27/156 (17.3%, 95% CI: 11.5 - 23.1). Our results show an association between HBV DNA or HBsAg and anti-HBc S/CO levels ≥ 4.0. All DNA samples were identified as genotype H and some "a" determinant mutations were identified, although none corresponded to mutations previously reported to hinder the detection of HBsAg by commercial immunoassays.

CONCLUSIONS

We observed that as the anti-HBc levels increase, there is a higher prevalence of the viral protein HBsAg in blood donors. Samples testing positive for HBV-DNA were seen to exhibit a ten-fold higher presence of anti-HBc S/CO ≥ 4 than those with S/CO ≥ 1 and < 4.0, which highlights the relevance of anti-HBc determination in blood donor samples.

Perfiles serológicos de hepatitis B en donantes de sangre con anti-HBc reactivos

<p><strong>Objetivo </strong>Determinar los perfiles serológicos para el virus de hepatitis B, en donantes de sangre anti-HBc reactivo y antígeno de superficie no reactivo, provenientes de cuatro ciudades del país<strong></strong></p><p><strong>Métodos</strong> Se realizó un estudio prospectivo transversal, durante un período de 17 meses, aplicando el perfil serológico completo de la hepatitis B, en muestras de donantes con anti-HBc reactivo y antígeno de superficie de hepatitis B no reactivo. Los resultados fueron analizados utilizando Microsoft^® Excel y Epiinfo V 3.5.1.</p><p><strong>Resultados </strong>Se encontró que el 75 % de los donantes reactivos para anti-HBc en los bancos de sangre, presentaban algún marcador adicional de exposición para el VHB; el 1,3 % de los donantes presentaban marcadores serológicos de infección crónica por hepatitis B y un caso que resultó reactivo solamente para antígeno de superficie de hepatitis B. Se halló perfil de vacunación en el 6,1 % de donantes, que fueron reactivos solamente para anticuerpo contra antígeno de superficie.</p><p><strong>Conclusiones. </strong>Se ratifica la importancia de la tamización de anti-HBc, a los donantes de sangre.</p>

Occult hepatitis B virus infection and blood transfusion

Transfusion-transmitted infections including hepatitis B virus (HBV) have been a major concern in transfusion medicine. Implementation of HBV nucleic acid testing (NAT) has revealed occult HBV infection (OBI) in blood donors. In the mid-1980s, hepatitis B core antibody (HBc) testing was introduced to screen blood donors in HBV non-endemic countries to prevent transmission of non-A and non-B hepatitis. That test remains in use for preventing of potential transmission of HBV from hepatitis B surface antigen (HBsAg)-negative blood donors, even though anti-hepatitis C virus tests have been introduced. Studies of anti-HBc-positive donors have revealed an HBV DNA positivity rate of 0%-15%. As of 2012, 30 countries have implemented HBV NAT. The prevalence of OBI in blood donors was estimated to be 8.55 per 1 million donations, according to a 2008 international survey. OBI is transmissible by blood transfusion. The clinical outcome of occult HBV transmission primarily depends on recipient immune status and the number of HBV DNA copies present in the blood products. The presence of donor anti-HBs reduces the risk of HBV infection by approximately five-fold. The risk of HBV transmission may be lower in endemic areas than in non-endemic areas, because most recipients have already been exposed to HBV. Blood safety for HBV, including OBI, has substantially improved, but the possibility for OBI transmission remains.

Occult HBV infection: a faceless enemy in liver cancer development

The hepatitis B virus (HBV) represents a worldwide public health problem; the virus is present in one third of the global population. However, this rate may in fact be higher due to occult hepatitis B virus infection (OBI). This condition is characterized by the presence of the viral genome in the liver of individuals sero-negative for the virus surface antigen (HBsAg). The causes of the absence of HBsAg in serum are unknown, however, mutations have been identified that produce variants not recognized by current immunoassays. Epigenetic and immunological host mechanisms also appear to be involved in HBsAg suppression. Current evidence suggests that OBI maintains its carcinogenic potential, favoring the progression of fibrosis and cirrhosis of the liver. In common with open HBV infection, OBI can contribute to the establishment of hepatocellular carcinoma. Epidemiological data regarding the global prevalence of OBI vary due to the use of detection methods of different sensitivity and specificity. In Latin America, which is considered an area of low prevalence for HBV, diagnostic screening methods using gene amplification tests for confirmation of OBI are not conducted. This prevents determination of the actual prevalence of OBI, highlighting the need for the implementation of cutting edge technology in epidemiological surveillance systems.

Evaluation of commercialized rapid diagnostic testing for some Hepatitis B biomarkers in an area of intermediate endemicity

Hepatitis B virus (HBV) is a major public health threat. Enzyme immune assay (EIA) of HBsAg is the screening method used in most settings, including in blood banks. Other markers are used to evaluate the HBV replication, immunity and the infectious level of the patient. Testing negative for HBsAg, however, does not always mean the absence of infection, and testing other markers using EIA is costly. This study evaluated the diagnostic reliability of commercially available non-HBsAg HBV biomarkers to detect their usefulness to screen for HBV infection. INTEC rapid tests for HBV markers were evaluated in 508 HBsAg negative blood donors and were compared to EIA as a reference method. Only anti-HBs, anti-HBc and anti-HBe could be evaluated. Sensitivities of all tests (64.2, 85.48, and 82.78 respectively) were much lower than those claimed by the manufacturer. The specificities and negative predictive values for all tests exceeded 95% and 93% respectively and were lowest for anti-HBs. Anti-HBe had the highest accuracy (99.02%), while anti-HBs had the lowest (90.16%). It was concluded that the rapid test performance was lower than the manufacturer's reports. They are reliable tools to prove negativity, but less efficient to confirm reactivity. The best performance was for anti-HBe. The positive results of anti-HBs was significantly associated with higher ELISA titer levels, which is therefore recommended to be used for screening of immunity.

Stochastic model for estimating the risk of transfusion-transmitted hepatitis B in Vietnam

BACKGROUND AND OBJECTIVE

Transfusion-transmitted hepatitis B virus (HBV) infection may originate from hepatitis B surface antigen (HBsAg) false-negative blood donors, HBsAg negative and anti-HBc positive blood donors and blood donors with both tests negative. HBV DNA may be present in all these cases and blood may be infectious. The aim of the study was to estimate the risk of transfusion-transmitted HBV in Vietnam using a stochastic Monte Carlo model.

METHODS

A cross-sectional study of HBV prevalence in 1200 potential blood donors in rural Vietnam is used as basis for the Monte Carlo model together with expert panel estimates of occult hepatitis B infection (OBI) prevalence in blood donors.

RESULTS

With 1 000 000 blood donors running in the model, the potential OBI ranged from 658 to 747 blood units per million at 5 percentile and from 1342 to 2507 blood units per million at 95 percentile resulting in the risk of post-transfusion hepatitis ranging from 66 to 250 blood units per million assuming that risk of post-transfusion from potential OBI is 10%. Using the manufacturer's HBsAg sensitivity, the mean rate of blood units per million donations having false-negative HBsAg results was 298 (5-95 percentile: 14-893). When the test sensitivity was set lower, false-negative tests was observed at a mean of 1087 per million (5-95 percentile: 762-3220). The fraction of potential OBI donors increased with the increasing age in both genders.

CONCLUSION

Current HBsAg screening in Vietnam is insufficient in eliminating the risk of transfusion-transmitted HBV infection. The major risk factors are HBsAg false-negative results and OBI. Increased test sensitivity and locally validated HBsAg assays are recommended.

Significance of screening antibodies to hepatitis B virus core antigen among Syrian blood donors

BACKGROUND

Hepatitis B virus (HBV) transmission via hepatitis B surface antigen (HBsAg)-negative blood donors has been reported. While many countries have implemented screening antibodies to hepatitis B core antigen (anti-HBc) to further enhance transfusion safety, HBsAg is still the only obligatory HBV screening test of blood donors in Syria.

OBJECTIVE

To evaluate the significance of screening anti-HBc to reduce the risk of transfusion transmitted HBV infection in Syria.

METHODS/MATERIALS

A cohort cross-sectional prospective study included 1939 healthy blood donors assigned at the blood transfusion center of Damascus University. All donors were tested for HBsAg and anti-HBc. HBsAg-negative, anti-HBc-positive sera were further tested quantitatively for antibodies to hepatitis B surface antigen (anti-HBs) and 'anti-HBc alone' sera were considered for HBV quantitative real time polymerase chain reaction (qPCR).

RESULTS

Among 1913 HBsAg-negative donors, 215 (11·2%) were anti-HBc-positive including 125 anti-HBs high-positive and 59 anti-HBs low-positive donors. The remaining 31 donors were 'anti-HBc alone', five of which were HBV DNA-positive.

CONCLUSION

Our results suggest including anti-HBc as an additional screening test for blood donors in Syria to reduce the risk of HBV transmission. As the most cost-effective measure, anti-HBc-positive donors should be tested quantitatively for anti-HBs and only donors with no or low (<100 IU L(-1) ) anti-HBs should be deferred.

The prevalence of "anti-HBc alone" and HBV DNA detection among anti-HBc alone in Korea

The "anti-HBc alone" is a frequent serological finding in clinical laboratories, making it difficult to determine whether the HBV infection has resolved. The objectives of this study were to investigate the prevalence of anti-HBc alone and HBV DNA detection (occult HBV infection) among anti-HBc alone, and to describe the demographic and clinical characteristics of anti-HBc alone. A total of 17,677 sera referred from the Health Promotion Center (HPC group, 4,014 sera) as well as all the hospital clinical departments (Patient group, 13,663 sera) were tested for HBs Ag, anti-HBc, and anti-HBs. HBV DNA test using real-time PCR was performed on 230 anti-HBc alone. The prevalence of anti-HBc alone was 8.9%, significantly higher in the Patient group than in the HPC group. The prevalence of anti-HBc was higher in men than women and was increased with age. Very low levels of HBV DNA were found in only 4 (1.7%) out of 230 subjects with anti-HBc alone. They were patients with conditions unrelated to chronic liver disease. Considering the high prevalence of anti-HBc alone, the frequency of occult HBV infection among anti-HBc alone was unexpectedly low. In addition, HBV viral load was low in these patients. Further studies are required to determine the clinical significance and infectivity of anti-HBc alone, in conjunction with very low levels of HBV DNA and to standardize the detection methodology for both anti-HBc alone and HBV DNA.

The underlying mechanisms for the 'anti-HBc alone' serological profile

The serological pattern, "anti-HBc alone", characterized by the presence of antibodies against the core antigen of hepatitis B virus (anti-HBc) as the only marker of hepatitis B, is not rare in a diagnostic setting. Depending on the prevalence of HBV infection and the patient group investigated, 1-31% of positive anti-HBc results are isolated positive findings. Anti-HBc alone is frequently observed in intravenous drug addicts, HIV-infected individuals, patients who are coinfected with HBV and hepatitis C virus, and pregnant women. However, it is not clear how this profile should be interpreted. Several studies have shown that anti-HBc alone is not only compatible with acute and resolved HBV infection but also with chronic infection. The reasons for the lack of HBsAg and anti-HBs in anti-HBc-alone individuals are not clear, but several mechanisms and possibilities have been suggested that could explain this phenomenon, some of which are delineated in this article.

Lack of occult hepatitis B virus infection among blood donors with isolated hepatitis B core antibody living in an HBV low prevalence region of Iran

BACKGROUND

Occult hepatitis B virus (HBV) infection in blood donors is considered a potential threat for the safety of the blood supply, however conclusive studies on this issue are lacking. The aim of this study was to assess the occult HBV infection in blood donors with isolated hepatitis B core antibody (anti-HBc) living in the city of Arak, in the Central Province of Iran, as a low prevalence region for HBV.

METHODS

A total of 531 voluntary blood donors in Arak, Iran were included in this study. Hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (anti-HBs), anti-HBc, and hepatitis C antibody (anti-HCV) were tested in all subjects. The presence of HBV-DNA was determined quantitatively in plasma samples of cases with isolated anti-HBc (HBsAg-negative, anti-HBs-negative, and anti-HBc-positive) by real-time PCR using the artus HBV RG PCR kit on the Rotor-Gene 3000 real-time thermal cycler.

RESULTS

Of 531 subjects enrolled in this study, 11 (2.1%, 95% confidence interval 0.8-3.2%) had isolated anti-HBc. HBV-DNA was not detected in any of the cases with isolated anti-HBc.

CONCLUSIONS

Our study showed that all the blood donors with isolated anti-HBc were negative for HBV-DNA, and occult HBV infection did not occur in the blood donors of this low prevalence region for HBV infection.

Efficacy of hepatitis B virus (HBV) DNA screening and characterization of acute and occult HBV infections among blood donors from Madrid, Spain

BACKGROUND

Screening of blood units for hepatitis B virus (HBV) DNA identifies donations collected during the window period (WP) of the acute infection and may improve viral safety of the blood supply. It also leads to the detection of occult hepatitis B infection (OBI).

STUDY DESIGN AND METHODS

From January 2005 to December 2006, a total of 383,267 blood units were screened for hepatitis B surface antigen (HBsAg) and HBV DNA in two transfusion centers in Madrid, using either individual-donation nucleic acid testing (ID-NAT) or minipool (MP-NAT) of eight donations (MP8). Samples positive for HBV DNA and negative for HBsAg were confirmed by a second molecular test, the viral DNA was quantified, and a genome fragment including the region encoding the major hydrophilic region (MHR) of HBsAg was sequenced.

RESULTS

The overall yield of HBV DNA-positive, HBsAg-negative units was 1 in 21,282 (18 cases), higher when using ID-NAT than MP8-NAT (1:9862 vs. 1:51,011; p < 0.01). Four donations (1/95,817) were collected during the infectious pre-HBsAg WP, one during an early recovery stage, and the remaining 13 (1/29,482) were OBIs, six of whom had no detectable antibody to HBsAg. Low-level Genotype D HBV DNA was detected in all OBI cases; the frequencies of this genotype and MHR amino acid substitutions were significantly higher than reported from unselected Spanish HBsAg carriers. Donors with OBI had normal aminotransferase levels and were significantly older than donors carrying HBsAg.

CONCLUSIONS

Blood donors in the WP and with OBI are not uncommon in Madrid and are detected at a higher frequency with ID-NAT than MP-NAT.

Clinical significance of antibody to hepatitis B core antigen in multitransfused hemodialysis patients

BACKGROUND

In spite of the progress made in the prevention of transfusion transmitted infections over the last few years, transmission of HBV infection through transfusion of HBsAg negative blood has been documented.

OBJECTIVES

To assess the frequency and clinical significance of anti-HBc in multitransfused hemodialysis patients.

MATERIALS AND METHODS

One hundred and forty-three hemodialysis patients who had been receiving blood regularly with an average of 39.4 +/- 7.579 months on hemodialysis were enrolled in this study. HBV markers (HBsAg, anti-HBc, anti-HBs) were measured in these patients and in 100 healthy controls by the ELISA technique. The following data were obtained for all patients: socio demographic data, number of blood transfusions and some laboratory investigations.

RESULTS

In our patients, anti-HBc was positive in 9%, anti HBs in 7%, coexistant HbsAg/anti-HBc in 2.8% and anti HBc/anti HBs in 18.9%, meanwhile no patients were positive for HBsAg alone. In patients with only positive anti-HBc, the levels of anti-HBc were significantly related to abnormal results of liver function. In patients with positive anti-HBs/anti-HBc (n = 27), 18 patients had abnormal liver function, and 9 patients had normal liver function with no significant difference between them.

CONCLUSIONS

This study suggests that hepatitis B prevalence in our multitransfused hemodialysis patients is far in excess of that anticipated on the basis of HBsAg prevalence. Absence of HBsAg in the blood of hemodialyzed patients may not be sufficient to ensure lack of circulating HBV, and isolated positivity of anti-HBc may be a possible indicator of active hepatitis B infection.

Detection and characterization of hepatitis B virus of anti-hepatitis B core antigen-reactive blood donors in Quebec with an in-house nucleic acid testing assay

BACKGROUND

Hepatitis B virus (HBV) infection can be detected in blood donations by many serologic markers. Since the introduction of routine anti-hepatitis B core antigen (HBc) donor screening at Héma-Québec in April 2003, a large number of donors have been deferred on the basis of reactive anti-HBc test results. The objective of this study was to evaluate the correlation between the anti-HBc-reactive donations and the detection of HBV DNA with an in-house nucleic acid testing (NAT) assay.

STUDY DESIGN AND METHODS

The in-house HBV NAT assay is a conventional polymerase chain reaction amplifying part of the viral S gene. From October 2004 to November 2005, a total of 1169 anti-HBc-reactive donations were tested with this in-house assay. The results were correlated with hepatitis B surface antigen (HBsAg) and anti-HBs markers. HBV DNA-positive samples were further investigated by DNA sequencing.

RESULTS

All HBsAg-positive samples were detected by the NAT assay. Overall, 38 (3.25%) of anti-HBc-positive samples were found to be positive for the presence of HBV DNA. Of these 38, a total of 12 donations with a low level of HBV DNA were HBsAg-negative. The sequencing results clearly showed various genotypes and subtypes within a same genotype.

CONCLUSION

The 3.25 percent HBV DNA positivity rate among the anti-HBc-reactive donations and more particularly the low level of HBV DNA observed in occult donations underline the importance of the use of a sensitive assay to detect HBV DNA in conjunction with other markers. The HBV genetic diversity found in our donor population reflects the province demographics, particularly in the Montreal area where most of the positive donors were from.

Epidemiology of hepatitis virus B and C

Hepatitis B and C virus infections constitute a significant health problem in Latin America. Approximately 400,000 new cases of hepatitis B per year and 10 million people infected with hepatitis C are estimated to occur. HBV and HCV genotype distribution may reflect the different patterns of migration to the Americas: Genotype F and H of HBV correspond to the Amerindian genotype. Overall, Genotype 1 is the most prevalent HCV genotype in the Caribbean and in South and Central America. Hepatitis B and C epidemiology needs to be considered in the context of dissimilar social and economic aspects among the countries of the region. Behaviors, cultural and ethical aspects, as well as environmental and organizational processes affect directly the way these diseases are approached in their diagnosis, treatment and prevention.