Agricultural Academy

Abstract ATANASSOVA, I., M. TEOHAROV and P. IVANOV, 2009. Characterisation of a fire affected catena sequence from Lyulin Mountain, Bulgaria. Bulg. J. Agric. Sci., We analysed the effects of a forest fire having occurred in the late summer of 2007 on major characteristics and properties of surface soils and soil profiles characterised as a catena sequence. The objectives of our study were to carry out a detailed morphological description of the individual soil profiles on the ridge and slopes of Lyulin mountain and analyse other chemical, physico-chemical and mineralogical characteristics in the surface horizons mostly affected by fire. Our key findings are: (1) changes were observed in the surface depths and concern mainly the soil organic carbon, primary minerals mineralogy and texture; (2) no major changes in the cation exchange capacity and exchangeable Ca and Mg cation composition between the surface and the lower depths of the soil profiles were found and no additional release of bases as a result of burning was accounted for; (3) total organic carbon increased in all the burnt soils, due to partially combusted organic remnants. As a result of the detailed analysis of the catena sequence we conclude that the fire that occurred was not of high severity and had mainly affected the ridge of the mountain and the surface depths of the higher parts of the hillslope

Molecular analysis of hepatitis C virus infection in Bulgarian injecting drug users

Intravenous drug users constitute a group at risk for hepatitis C virus (HCV) infection. Today, no data are available on the molecular epidemiology of HCV in Bulgaria despite the fact that in recent years the incidence of acute hepatitis C infection among Bulgarian intravenous drug users increased sixfold and about 2/3 of them developed a chronic infection. The aim of this study was to determine the circulation of hepatitis C genotypes among drug users and to study the evolution and transmission history of the virus by molecular clock and Bayesian methods, respectively. Sequencing of NS5B gene showed that the genotype 3a was the most prevalent type among intravenous drug users. In the Bayesian tree, the 3a subtypes grouped in one main clade with one small cluster well statistically supported. The root of the tree was dated back to the year 1836, and the main clade from Bulgaria was dated 1960. The effective number of infections remained constant until about years 1950s, growing exponentially from the 1960s to the 1990s, reaching a plateau in the years 2000. The not significant intermixing with isolates from other countries may suggest a segregated circulation of the epidemic between 1940s and 1980s. The plateau reached by the epidemic in the early 2000s may indicate the partial success of the new preventive policies adopted in Bulgaria. J. Med. Virol. 83:1565-1570, 2011. © 2011 Wiley-Liss, Inc

Molecular analysis of hepatitis B virus in Bulgaria

Hepatitis B virus infection is a global health problem. Based on the sequence divergence of the entire genome, hepatitis B virus has been classified into eight genotypes which have a characteristic geographic distribution. To date, no data are available on the molecular epidemiology of hepatitis B virus in Bulgaria. The aim of the present study was to reconstruct the epidemiological history of HBV genotypes/subgenotypes circulating in Bulgaria using a phylodynamic approach and a Bayesian statistical inference framework. Sequence analysis of the HBsAg/Reverse Transcriptase overlapping genomic regions revealed that D1 and A2 were the subgenotypes detected most frequently in the patients examined. The tMRCA estimations of the few HBV D1 Bulgarian significant clades dated back to 23-27 years ago, corresponding to the early 1980s. The HBV A2 Bulgarian sequences fell into two closely related supported clusters dated to 2003 and 1996 years, respectively, suggesting a more recent introduction of subgenotype A2 into Bulgaria. The study provides new information about the HBV subgenotypes in Bulgaria. J. Med. Virol. 85:49-54, 2012. © 2012 Wiley Periodicals, Inc

The long-term immunogenicity of recombinant hepatitis B virus (HBV) vaccine: contribution of universal HBV vaccination in Italy

Universal hepatitis B virus (HBV) vaccination of newborn babies was introduced in Italy in 1991 and was extended to 12-years-old children for the first 12 years of application so as to cover in a dozen years the Italian population aged 0-24 years. The aim of this study was to identify factors associated with long-term immunogenicity against HBV 17 years after primary vaccination in students attending medical schools in Naples, Italy