Seroprevalence of herpes simplex virus type 1 and type 2 - data from a hospital-based study in Varna, northeastern Bulgaria, 2019-2021.

The purpose of the current study was to describe the prevalence of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in northeastern Bulgaria. From January 2019 to December 2021, we tested 1493 samples for anti-HSV-1 IgG and 817 samples for anti-HSV-2 IgG antibodies in the Virology Laboratory, "St. Marina" University Hospital, Varna, Bulgaria. HSV-1 was considerably more widespread, with an overall seroprevalence of 73.3% (95% CI: 71.0-75.5%), than HSV-2 infection, which showed a seropositive rate of 10.0% (95% CI: 8.1-12.4%). Age was the most significant risk factor for both infections, while gender had no role in herpes simplex seropositivity.

Dealing with inconclusive SARS-CoV-2 PCR samples-Our experience.

PURPOSE: Early confirmation of SARS-CoV-2 is a key point in the timely management of infected patients and contact persons. Routine diagnostics of COVID-19 cases relies on RT-PCR detection of two or three unique sequences of the virus. A serious problem for the laboratories is how to interpret inconclusive samples which are positive for only one of the SARS-CoV-2 specific genes. MATERIALS AND METHODS: A total of 16364 naso-oropharyngeal swabs were collected and tested with SARS-CoV-2 Real-TM kit (Sacace Biotechnologies, Italy) between May and September 2020. We retrospectively analyzed their amplification plots to determine the number of inconclusive samples. We also reviewed the medical records to summarize the patient's COVID-19 testing history and basic demographic characteristics. RESULTS: We obtained 136 (0.8%) inconclusive samples with amplification signal only for the N-gene. Thirty-nine of the samples were excluded from further analysis as no additional data were available for them. Of the rest of the samples, the majority- 48% (95% CI 38-59%) had a previous history of SARS-CoV-2 positivity, 14% (95% CI 8-23%)-a subsequent history of positivity and 37% (95% CI 28-48%) were considered as false positive. CONCLUSION: A substantial proportion of the inconclusive results should be considered as positive samples at the beginning or the end of the infection. However, the number of false-positive results is also significant and each patient's result should be analyzed separately following the clinical symptoms and epidemiological data.

Epidemiological study of Lyme disease in Bulgaria.

OBJECTIVES: Lyme disease (Lyme borreliosis) is a transmissible infection, common in the temperate climate zones. It is caused by a group of spirochetal bacteria known as Borrelia burgdorferi sensu lato complex. The aim of the present work was to investigate the incidence rate of borreliosis in different regions of Bulgaria and to identify possible risk factors for its occurrence. METHODS: National and regional borreliosis incidence rates for 2009-2018 were obtained from the public database of the National Centre of Public Health and Analyses. Their association with some socio-demographic variables and the geographic location (south or north) of the regions was tested with Spearman's correlation analysis and simple linear regression. RESULTS: The mean annual incidence for the last 10 years (2009-2018) in Bulgaria was 6.9 (range 4.1-11.6) cases per 100,000 inhabitants. We found that the Lyme disease was highly fluctuating at regional level with incidence rates varied from 0.3 to 30.9 per 100,000 inhabitants. Several regions showed significantly higher endemicity for the disease. Socio-demographic factors were not found to be important for Lyme disease frequency while the geographic location in the north part of the country was a significant risk factor for it. CONCLUSIONS: Lyme disease is a serious health risk in Bulgaria especially in its northern part - regions on the north are the most vulnerable to a higher incidence of the disease.

Seasonal influenza vaccination: knowledge, attitude and practice in Varna, Bulgaria.

BACKGROUND: Seasonal influenza vaccination is recommended for certain at-risk groups in Bulgaria, but vaccine coverage and the population's perception of vaccination are currently unknown. The objective of this study was to assess the level of seasonal influenza vaccination in Varna Region, Bulgaria. It also aimed to investigate the status of knowledge and the attitude towards the reliability, safety, and other aspects associated with the use of influenza vaccines. METHODS: A cross-sectional survey was conducted among 120 responders in Varna Region, Bulgaria. They completed a questionnaire assessing the practice, knowledge, and attitude towards seasonal influenza vaccination. RESULTS: Nearly 70% of all responders have never been vaccinated against seasonal influenza in their lives. The main reason indicated was a lack of confidence in the vaccine in general (53.7% of nonvaccinated responders). Individuals with insufficient knowledge, or with a negative perception, were more likely to not be vaccinated: being poorly informed and having a negative attitude towards influenza vaccination also decreased the chance of being vaccinated by 29% and 36%, respectively. CONCLUSIONS: This study indicates that efforts should be made towards achieving better understanding and knowledge of the vaccine's mechanism of prevention and effectiveness among the Bulgarian population.

Detection of EBV DNA in Non-Hodgkin Lymphoma Patients in Bulgaria.

Epstein-Barr virus is the first human oncogenic virus associated with a broad range of different malignant diseases but its role in non-Hodgkin lymphomas (NHL) development still needs to be fully understood. High expression levels of EBV major genes are found in NHL tumor cells and free viral DNA circulates in the plasma of such individuals. In the current study we detected EBV DNA levels in plasma samples from NHL patients in order to validate its significance as a laboratory marker for disease monitoring. We investigated a cohort of 52 patients diagnosed with NHL in The University Hospital "St. Marina" Varna, Bulgaria. Viral DNA was extracted from single plasma samples using Kit Ribo Virus (Sacace Biotechnologies S.r.l., Como, Italy) and amplified with EBV Real-TM Quant (Sacace Biotechnologies S.r.l., Como, Italy). Plasma samples of the same patients were tested for presence of EBV VCA IgM/IgG antibodies with indirect ELISA tests (Euroimmun, Luebeck, Germany). We found 15.4% (95% CI 6.9-28.1%, n = 8) of the samples from NHL patients to be positive in quantitative PCR (range 674-221,333 copies/ml). The diffuse large B cell lymphomas and peripheral T cell lymphomas were most often associated (although not statistically significant, p = 0.167) with detectable plasma EBV DNA levels. To our knowledge, this is the first study about the role of EBV in NHL development in Bulgaria. The results we have obtained should stimulate new, larger investigations to apply the quantitative PCR technique in the routine laboratory EBV diagnosis.

Varicella infection in a non-universally vaccinated population: Actual epidemiology in Bulgaria (2013-2015).

BACKGROUND: Varicella is a common and usually mild disease but it has great importance in regard to general infectious morbidity. The current study aimed to characterize possible risk factors of varicella epidemiology in Bulgaria, a country where infection follows its natural epidemiological pattern as no mandatory or recommended vaccine is currently applied. METHODS: Administrative regions of Bulgaria were used as units of observation and a set of sociodemographic and economic determinants, as well as geographic location (south or north) were tested for associations with the mean 3-year varicella incidence rates (2013-2015). RESULTS: The proportion of urban population, proportion of females, number of health care units and proportion of urban population aged <10 years were the four sociodemographic variables most strongly and significantly correlated (p<0.05) with varicella frequency (Spearman's rank correlation coefficients of 0.62, 0.47, 0.43, and 0.38, respectively). After reducing the number of intercorrelated factors to a few principal components and accounting for confounders, the demographic component and geographic location remained most robustly associated with varicella incidence in Bulgaria (adjusted R2 of 0.51, p<0.001). CONCLUSIONS: The results obtained identify important determinants in the local epidemiology of varicella and show that community characteristics should be considered, to improve our understanding of varicella distribution.

The Role of Cytomegalovirus in Congenital and Early Postnatal Infections in Northeastern Bulgaria.

BACKGROUND: Human cytomegalovirus is a ubiquitous, large enveloped DNA ß-herpesvirus that, like other herpesviruses, establishes lifelong latency following primary infection. It is the most frequent cause of congenital, neonatal and early postnatal infections with long lasting sequelae. AIM: The aim of the present study was to assess the prevalence of cytomegalovirus among a cohort of newborns and 1-3-month-old children with neurological symptoms, physical retardation, prolonged jaundice, thrombocytopenic purpura and other disabilities. MATERIALS AND METHODS: The study was a retrospective cross-sectional analysis of serological screening data for detection of specific anti-cytomegalovirus IgM and IgG in children from Northeastern Bulgaria. RESULTS: Between 2003 and 2015, average prevalences of 18.8% (95% CI: 15.4 to 22.2) for anti-CMV IgM antibodies (suggesting acute infection) and 84.7% (95% CI: 81.6 to 87.8) for anti-CMV IgG antibodies were measured in a total number of 517 samples. The prevalence rate of anti-CMV IgM in 1-3-month-old children was 4-fold higher than that in newborns [25.8% (95% CI: 21.1 to 30.5) and 6.4% (95% CI: 2.9 to 9.9, respectively]. In contrast, no significant difference was found for anti- CMV IgG positivity between newborns and 1-3-month-old infants (84% and 85%, respectively). CONCLUSIONS: The data obtained strongly encourage screening of pregnant women for anti-CMV IgG and IgM to avoid transmission of the infection and severe complications of congenital infection.

Epidemiological Study of Hepatitis A Infection in Eastern Bulgaria.

BACKGROUND: Hepatitis A virus (HAV) infection is an acute, self-limited liver disease transmitted usually through the faecal-oral route via person-to-person contact. Bulgaria has intermediate HAV endemicity with higher susceptibility among adults and recurrent outbreaks. AIM: As HAV infection is strongly related to human movements and represents a significant risk to travelers and migrants, as well as to local population receiving these groups, we set out to analyze the epidemiological data on hepatitis A in five of the largest tourist border regions of Bulgaria located in its eastern part: Varna, Shumen, Dobrich, Burgas and Yambol. MATERIALS AND METHODS: We reviewed retrospectively all reported cases of acute hepatitis A in the eastern regions of Bulgaria over a 7-year period between 2008 and 2014. RESULTS: A total of 2879 newly infected patients were registered during the study period, the number varying widely: from 190 cases in 2014 to 923 in 2012. The average incidence of HAV was higher in the south-eastern regions than in the northeastern regions (55.30%000 vs 15.04%000 respectively, p < 0.0001). The most affected age group in all regions was the 5-9-year olds (p < 0.0001) and males were significantly more susceptible to HAV (p = 0.02). CONCLUSION: Hepatitis A is still a major public health problem in Bulgaria; there is a significant difference in the incidence of the disease between the regions in the south-east and those in the north-east and between the different age groups and sexes.

Seroprevalence of hepatitis B among pregnant women in Varna Region, Bulgaria.

The aim of the present study was to assess the prevalence of hepatitis B surface antigen among pregnant women in Varna Region, Bulgaria. During the period 2009-2013, an average prevalence of 2.26% (95%CI 1.75, 2.91) was measured in a total number of 2,700 samples. Analysis demonstrated that rural residence and minority ethnic origin are important risk factors for hepatitis B infection among pregnant women with hazard ratios of 2.40 (95%CI 1.46, 3.94), and 2.43 (95%CI 1.46, 4.05) when compared with urban residence and ethnic majority origin, respectively. J. Med. Virol. 88:2012-2015, 2016. © 2016 Wiley Periodicals, Inc.

Seroprevalence of Syphilis among Pregnant Women in the Varna Region (Bulgaria).

Syphilis is a sexually transmitted disease with continuously rising rates among European countries. The vertical (mother to child) transmission is an important way of dissemination, often leading to stillbirth and permanent impairment of the newborn. We present a retrospective cross-sectional analysis of 2702 pregnant women tested for syphilis seropositivity. During the study period (2009-2013) non-specific and specific treponemal antibodies were detected in 15 pregnant women (0.56% of sample size with 95% confidence interval (CI) 0.28-0.84). Our results showed a lack of correlation between syphilis seropositivity and age, ethnic origin, or pregnancy trimester of the mother. The only factor found to influence syphilis seropositivity was the mother's place of residence - rural inhabitants had significantly higher risk for syphilis infection when compared to urban inhabitants, with a seropositive proportion of 1.08% versus 0.36%, respectively.

Non-enzymatic roles for the URE2 glutathione S-transferase in the response of Saccharomyces cerevisiae to arsenic.

The response of Saccharomyces cerevisiae to arsenic involves a large ensemble of genes, many of which are associated with glutathione-related metabolism. The role of the glutathione S-transferase (GST) product of the URE2 gene involved in resistance of S. cerevisiae to a broad range of heavy metals was investigated. Glutathione peroxidase activity, previously reported for the Ure2p protein, was unaffected in cell-free extracts of an ure2Δ mutant of S. cerevisiae. Glutathione levels in the ure2Δ mutant were lowered about threefold compared to the isogenic wild-type strain but, as in the wild-type strain, increased 2-2.5-fold upon addition of either arsenate (As(V)) or arsenite (As(III)). However, lack of URE2 specifically caused sensitivity to arsenite but not to arsenate. The protective role of URE2 against arsenite depended solely on the GST-encoding 3'-end portion of the gene. The nitrogen source used for growth was suggested to be an important determinant of arsenite toxicity, in keeping with non-enzymatic roles of the URE2 gene product in GATA-type regulation.

Response to different oxidants of Saccharomyces cerevisiae ure2Delta mutant.

Growth of Saccharomyces cerevisiae ure2Delta mutant strain was investigated in the presence of diverse oxidant compounds. The inability of the strain to grow on a medium supplemented with H(2)O(2) was confirmed and a relationship between diminishing levels of glutathione (GSH) and peroxide sensitivity was established. Data for the lack of significant effect of URE2 disruption on the cellular growth in the presence of paraquat and menadione were obtained. The possible role of Ure2p in acquiring sensitivity to oxidative stress by means of its regulatory role in the GATA signal transduction pathway was discussed. It was suggested that the susceptibility of ure2Delta mutant to the exogenous hydrogen peroxide can result from increased GSH degradation due to the deregulated localization of the gamma-glutamyl transpeptidase activating factors Gln3/Gat1. The important role of Ure2p in in vivo glutathione-mediated reactive oxygen species (ROS) scavenging was shown by measuring the activity of antioxidant enzymes glutathione peroxidase, superoxide dismutase (SOD) and catalase in an URE2 disrupted strain. A time-dependent increase in SOD and catalase activity was observed. More importantly, it was shown that the ure2 mutation could cause significant disturbance in cellular oxidant balance and increased ROS level.