Hepatitis B virus genotypes and subgenotypes and the natural history and epidemiology of hepatitis B.

INTRODUCTION AND OBJECTIVES: Espírito Santo state is considered a region with a higher frequency of hepatitis B virus infection. This study characterized demographic, epidemiological, laboratory, virological and clinical aspects of 587 chronic HBV carriers followed up at the University of Espírito Santo Hospital. MATERIALS AND METHODS: Demographic, epidemiological, laboratory and clinical data were extracted from medical records during the entire follow-up period. Classification of the evolutionary phases of chronic hepatitis B was defined as immunotolerant; inactive carrier; chronic active hepatitis HBeAg (+)  and HBeAg (-). Characterization of HBV genotypes/subgenotypes was performed by sequencing of overlapping surface antigens and HBV DNA polymerase genes. Phylogenetic relationships were determined using BEAST 1.8.3 software. RESULTS: and Conclusions: Genotypes found were A (132/65.3%) [A1 = 129 (63.9%) and A2 = 3 (1.5%)], D (66/32.7%) [D3 = 56 (27.7%), D4 = 8 (4.0%) and D2 = 2 (1.0%)] and F (4/2.0%) - all F2a. Subgenotypes A1 or D3 were not associated with age, sex, HIV/HCV co-infection, viral load, antiviral usage, HBeAg status or clinical stages of chronic hepatitis B. Mother -to-child-transmission (MTCT) was associated with the subgenotype A1 and intrafamilial transmission with subgenotype D3. Subgenotype A1 was more frequent than D3 among individuals born outside ES compared to those born in ES. CONCLUSIONS: The most predominant clinical phases were HBeAg (-), inactive carrier and chronic active hepatitis HBeAg (-). Subgenotypes A1 and D3 were most frequent and were associated were MTCT and intrafamilial transmission of HBV, respectively.

Comparison of interferon-γ release assay to two cut-off points of tuberculin skin test to detect latent Mycobacterium tuberculosis infection in primary health care workers.

BACKGROUND: An interferon-γ release assay, QuantiFERON-TB (QFT) test, has been introduced an alternative test for the diagnosis of latent Mycobacterium tuberculosis infection (LTBI). Here, we compared the performance of QFT with tuberculin skin test (TST) measured at two different cut-off points among primary health care work (HCW) in Brazil. METHODS: A cross-sectional study was carried out among HCWs in four Brazilian cities with a known history of high incidence of TB. Results of the QFT were compared to TST results based on both ≥5 mm and ≥10 mm as cut-off points. RESULTS: We enrolled 632 HCWs. When the cut-off value of ≥10 mm was used, agreement between QFT and TST was 69% (k = 0.31), and when the cut-off of ≥5 mm was chosen, the agreement was 57% (k = 0.22). We investigated possible factors of discordance of TST vs QFT. Compared to the TST-/QFT- group, risk factors for discordance in the TST+/QFT- group with TST cut-off of ≥5 mm included age between 41-45 years [OR = 2.70; CI 95%: 1.32-5.51] and 46-64 years [OR = 2.04; CI 95%: 1.05-3.93], BCG scar [OR = 2.72; CI 95%: 1.40-5.25], and having worked only in primary health care [OR = 2.30; CI 95%: 1.09-4.86]. On the other hand, for the cut-off of ≥10 mm, BCG scar [OR = 2.26; CI 95%: 1.03-4.91], being a household contact of a TB patient [OR = 1.72; CI 95%: 1.01-2.92] and having had a previous TST [OR = 1.66; CI 95%: 1.05-2.62], were significantly associated with the TST+/QFT- group. No statistically significant associations were found among the TST-/QFT+ discordant group with either TST cut-off value. CONCLUSIONS: Although we identified BCG vaccination to contribute to the discordance at both TST cut-off measures, the current Brazilian recommendation for the initiation of LTBI treatment, based on information gathered from medical history, TST, chest radiograph and physical examination, should not be changed.