PROBLEMS of Infectious and Parasitic Diseases 2022-02-25T07:57:30+00:00 Assoc. Prof. Dimitur Shalamanov Open Journal Systems <p><strong>"PROBLEMS of Infectious and Parasitic Diseases"</strong> <span id="result_box" class="" lang="en">is <span class="">a <a href="" target="_blank" rel="noopener">peer-reviewed</a> open-access medical journal of scientific papers covering laboratory research data on human infectious diseases as well as its application for elucidation and management of epidemic processes. It is published by</span></span><span id="result_box" class="" lang="en"> <a href="" target="_blank" rel="noopener">National Centre of Infectious and Parasitic Diseases</a> in English, </span>with periodicity of three issues annually, in a print and digital version.</p> <p style="text-align: justify;"><strong><span class="" lang="en"><span class="">ISSN: 0204-9155 (Print)</span></span></strong></p> <p style="text-align: justify;"><strong><span class="" lang="en"><span class="">ISSN: 2815-2808 (Online)</span></span></strong></p> SARS-COV-2: INSIGHT INTO THE EMERGING GENETIC VARIANTS 2021-08-27T06:46:50+00:00 Neli Korsun Ivelina Trifonova Veselin Dobrinov veselin.dobrinov@nci.pd Iliyana Grigorova iliyana.grigorova@nci.pd Svetla Angelova svetla.angelova@nci.pd Ivaylo Alexiev <p>SARS-CoV-2 is a highly contagious virus, which appeared in China in late 2019, spread rapidly and caused the largest pandemic in the last 100 years. Despite the intensive research, there is no specific antiviral drug currently. Effective vaccines have been developed in a short time and they are already widely used. As a RNA virus, SARS-CoV-2 mutates constantly, and several thousand genetic variants have emerged in the course of the pandemic, some of which are associated with increased infectivity, reinfection risk, reduced activity of therapeutic antibodies and reduced effectiveness of vaccines. This review highlights the features in SARS-CoV-2 structure and replication cycle that would help to understand the significance of individual mutations contained in the emerging genetic variants and to predict the impact of mutations on viral transmissibility, disease severity, diagnostics, therapeutics or immune escape. The main characteristics of the variants of concern are presented.</p> 2022-02-25T00:00:00+00:00 Copyright (c) 2022 Prof. Neli Korsun, Ivelina Trifonova, Veselin Dobrinov, Iliyana Grigorova, Svetla Angelova, Assoc. prof. Ivaylo Alexiev (Author) DRUG RESISTANCE MUTATIONS AND TRANSMISSION CLUSTERS OF THE HIV-1 CRF01_AE SUB-EPIDEMIC IN BULGARIA 2021-06-04T10:42:48+00:00 Lyubomira Grigorova Reneta Dimitrova Aleksandra Partsuneva Anna Gancheva Asya Kostadinova Ivaylo Elenkov Nina Yancheva Mariyana Stoycheva Tsetsa Doychinova Liliya Pekova Minas Kosmidis Ivailo Alexiev <p><strong>Background.</strong> In Bulgaria the second most predominant HIV-1 strain after subtype B is CRF01_AE.</p> <p><strong>Material and Methods.</strong> 270 HIV-1 polymerase (pol) CRF01_AE sequences collected between 1995–2019 were analyzed with the phylogenetic approach. To identify transmission clusters, we used two different genetic distance thresholds (d), i. e. 1.5% and 0.5%.</p> <p><strong>Results.</strong> Genetic distance d=1.5% defined more distant infections in a huge cluster of 154 sequences composed mostly of people, who inject drugs (PWID), whereas when (d) was reduced to 0.5%, we determined more recent transmissions and the large cluster disintegrated into smaller ones. Different drug resistance mutations (DRM) were detected in patient’s HIV-1 pol sequences and were most common in male heterosexual (HET) single sequences.</p> <p><strong>Conclusions.</strong> Our data showed repeated introduction of CRF01_AE in Bulgaria and rapid spread of the infection among PWID groups. Molecular monitoring of the epidemic among PWID communities could help reduce the spread of HIV-1 infection.</p> 2022-02-25T00:00:00+00:00 Copyright (c) 2022 Lyubomira Grigorova, Reneta Dimitrova, Aleksandra Partsuneva, Anna Gancheva, Asya Kostadinova, Ivaylo Elenkov, Nina Yancheva, Mariyana Stoycheva, Tsetsa Doychinova, Liliya Pekova, Minas Kosmidis, Ivailo Alexiev (Author) NOROVIRUSES - A HIDDEN THREAT 2021-09-13T07:54:12+00:00 Asya Stoyanova <p>Acute nonbacterial gastroenteritis is ubiquitous, and noroviruses are considered to be among the most common etiological agents. Noroviruses affect people of all ages. As a rule, infections caused by them are mild and self-limiting within 1-3 days but there is always a risk of a more severe course, especially in infants and the elderly. Being considered as mild and fast transient, noroviruses receive less attention than other infectious pathogens. The clinical and economic burden of norovirus gastroenteritis is often underestimated. Detection of the etiological role of noroviruses is essential not only from the clinical point of view, but also from the economic one because of the damage that norovirus infections cause to tourism and food industry. At present, prevention and counter disinfection measures are the only weapon against norovirus infections.</p> <p>In this narrative review, results from a non-systematic search on the recent literature on noroviruses are presented. The review describes the basic biological characteristics of noroviruses, their genetic diversity and current classification, as well as the epidemiological aspects of the norovirus infection, its clinical manifestation, the diagnostic approaches, prevention and control measures and current state-of-the art for norovirus vaccine development.</p> 2022-02-25T00:00:00+00:00 Copyright (c) 2022 Asya Stoyanova (Author) STUDIES ON THE EPIDEMIOLOGICAL AND MOLECULAR CHARACTERISTICS OF THE HEPATITIS E VIRUS IN BULGARIA: A COMPREHENSIVE REVIEW 2022-01-07T08:34:50+00:00 Elitsa Golkocheva-Markova Chiydem Ismailova Tencho Tencho Tenev Lubomira Nikolaeva-Glomb <p>Hepatitis E virus (HEV) is a RNA virus that belongs to the family Hepeviridae. The virus causes self-limited acute hepatitis in immunocompetent individuals, but can become chronic or present with extrahepatic manifestations in immunosuppressed patients. In recent years, due to the increased scientific interest in HEV infection, the number of laboratory-confirmed cases have also increased. The first study of HEV infection in Bulgaria was carried out in mid-90s of the last century by Teoharov et al. Ten years later, more in-depth studies of HEV infection began. The main focus was on the evaluation of HEV seroprevalence among different target populations. Attention was also paid to the zoonotic potential of the infection. The aim of the present review is to summarize studies on HEV conducted by Bulgarian authors in regards to HEV seroprevalence among humans and animals, clinical and epidemiological characteristics of HEV infection, and molecular-characteristics of HEV.</p> 2022-02-25T00:00:00+00:00 Copyright (c) 2022 Elitsa Golkocheva-Markova, Chiydem Ismailova, Tencho Tencho Tenev, Lubomira Nikolaeva-Glomb (Author) MOLECULAR AND MICROBIOLOGICAL APPROACHES FOR RAPID ETIOLOGICAL DIAGNOSIS OF SYSTEMIC MYCOSES 2022-01-07T08:43:09+00:00 Lyubomira Boyanova <p>The review presents common laboratory methods for the diagnosis of the majority of invasive fungal diseases, i. e. candidosis, aspergillosis and cryptococcosis. Some studies reveal an increasing range of the infectious agents such as Trichosporon and endemic fungal pathogens like Histoplasma, Blastomyces and Coccidioides.</p> <p>The most common serological tests for antigen and antibody-detection in body fluids (serum, plasma, bronchoalveolar lavage) are: indirect immunofluorescense, ELISA – Platelia (enzyme linked immunosorbent assay), latex-agglutination, immunodiffusion and molecular techniques like PCR and Real Time PCR.</p> <p>Not only current data on invasive fungal disease diagnostic methods are reviewed, but also studies on new biomarkers and recent discoveries in molecular diagnostics.</p> <p>New molecular approaches are needed to provide faster results.</p> 2022-02-25T00:00:00+00:00 Copyright (c) 2022 Lyubomira Boyanova (Author)