Southern Bulgaria Research Articles

First Report of Troglotrema acutum Trematoda Parasitizing a European Polecat (Mustela putorius) in Bulgaria

The finding also represents the first detection of this trematode on the Balkan Peninsula. The study was conducted between 2014 and 2023. Nineteen road-killed polecats, mainly from southern Bulgaria, were examined. A four-year-old male polecat road-killed near Chepelare, a town in the Somlyan Province in the Rhodope Mountains, was infested with six adult Troglotrema acutum within its frontal sinus. The skull exhibited only weakly developed lesions. The prevalence of 5.26% observed in this sample was lower than values reported from other European countries. This finding extends the known southeastern distribution range of T. acutum by over 700 km.

Генетично разнообразие на Sclerotinia sclerotiorum в България

The mycelial compatibility of 154 isolates of Sclerotinia sclerotiorum, obtained from sunflower and rapeseed plant samples, collected from 2019 - 2021 from 17 locations in Northern and Southern Bulgaria, was studied. The studied isolates were grouped into 108 local MCGs, and 60.1% included only one isolate. The Shannon index (Ho) at the studied locations varied from 0.718 to 1.00. The total diversity in MCG resulting from variation among individuals in the population was 92.2%, and the proportion of total diversity in MCG due to variation among populations was 7.78%. The clonal index for all populations was 0.299. In two of the six compatibility tests between isolates from different locations, 10 additional groups were formed, and one of them (MCGs-1D5x2D4x1SH3x1Y8) included six isolates from four locations (Dropla – Tsaricheno - Rish 1-Straldzha) located in three regions of the country. The results show significant genetic diversity in S. sclerotiorum populations based on mycelial compatibility between isolates.

Susceptibility of apple varieties to infestation by aphids (Hemiptera: Aphididae) in Southern Bulgaria

Aphids regularly infest apple orchards and are considered as one of the most damaging species, especially in humid conditions. In 2021-2023, the collection of different species and the rate of infestation by aphids on different apple varieties were studied in the region of Plovdiv, Bulgaria. Among the four aphid species identified in the apple orchard, Aphis spiraecola and Dysaphis plantaginea were predominant, followed by Aphis pomi and Dysaphis devecta. The rate of infestation varied significantly among the apple varieties. The Gala Resistant was the most infested by the aphids with a population coefficient (K) 302.5, followed by the Crimson Crisp – 124, the Pinova – 91, and the Red del Mestar – 52.5. The least infested variety was the Super Chief – 0.9, followed by the Modi – 2.2, the Fujion – 2.8, the Enterprise – 7.2 and the Rosella – 19. Keywords: apples, varietal susceptibility, aphids

Possibility for control with botanical insecticides against the mealy plum aphid Hyalopterus pruni Geoffroy, 1762 (Hemiptera: Aphididae) on the plum in Southern Bulgaria

The aim of this study was to evaluate the efficacy of botanical insecticides recommended for control of the mealy plum aphid Hyalopterus pruni (Hemiptera: Aphididae). The experiment was carried out in 2024 in the experimental field of the Fruit Growing Institute-Plovdiv, Bulgaria. The tested insecticides were orange oil (Limocid), liquid extract of Urtica spp. (Basictec) and pyrethrins (Abanto). The insecticides were applied at the recommended concentrations for control of aphids, whiteflies, thrips and other pests. All tested botanical insecticides showed high biological efficacy and can be used to control the mealy plum aphid. Keywords: mealy plum aphid, biological control, botanical insecticides, Limocid, Basictec, Abanto, Hyalopterus pruni

Effect of disturbed irrigation regime on the yield of Sudan grass, grown for the Southern Bulgaria environmental conditions

The aim of this study was to determine the effect of disturbed irrigation regime on dry biomass yield of Sudan grass. In the period 2021 - 2023 for the region of Stara Zagora on meadow - cinnamon soil was conducted an experiment with Sudan grass variety Endje - 1, grown after the precursor barley. The following variants were studied in the field trial 1 No irrigation (control), var. 2 Optimal irrigation 75-80% of FC (100% irrigation rate), var. 3 Irrigation with 70% of calculated irrigation rate, 4 Irrigation with 40% of calculated irrigation rate. It was found that the highest average yield of 13940 kg/ha dry biomass was obtained with the optimally irrigated variety, which was 36.5% higher than the yield of the non-irrigated variety. When the irrigation rate is reduced by 30% compared to the optimal option 1 (100%), the dry biomass yield decreases by 8.5%.

Reasons for Collapse of Steel Silos for Wheat with 1600 M3 Capacity

In 2021, five silos for grain storage were ordered, delivered and mounted for expansion of a warehouse in southern Bulgaria. They were produced of thin-walled galvanized sheets. The sheets were corrugated to prevent local loss of stability. All elements were joined together with bolts to facilitate and speed up the mounting processes. After completion of the mounting works, all five silos were filled up to the roof with grains. Three were filled with wheat, and the remaining two with sunflower seeds. On August 16, 2021, at about 8:30 am, a few minutes after the beginning of the first unloading of one of them, its cylindrical shell had torn, and it collapsed. A team from the University of Architecture, Civil Engineering and Geodesy (UACEG) was invited to inspect the accident site and determine the causes of the collapse. For this purpose, the members of the team carefully inspected the structure of the collapsed silos, tested samples of the used material and made control calculations. Through these activities, they established the most likely causes for steel silos destruction.

Mental Health Disorders of Bulgarian Healthcare Professionals during a Recurring Wave of the COVID-19 Pandemic

Introduction: During the COVID-19 pandemic, health hazards for medical professionals are associated not only with the high risk of infection, but also with poor working conditions, a stressful psychosocial environment and several socio-demographic factors. Objectives: The study aims to gain insight into possible mental health disorders among healthcare professionals working in the Bulgarian healthcare system and to determine which professional and socio-demographic categories are most significantly affected. Methods: This cross-sectional study was conducted in October 2022 in healthcare facilities from seven regions in Southern Bulgaria. A total of 665 workers from hospitals, emergency centers, general and specialized medical practices, and medical laboratories filled out the self-assessment mental health questionnaire DASS-21 (Depression, Anxiety and Stress Scale), as well as a survey about their occupational and socio-demographic characteristics. Suitable statistical methods were used to assess the scientific hypothesis. Results: 40% of all surveyed healthcare workers had some type of self-reported mental health disorder, with 27% having more than one. 13% had simultaneous signs of depression, anxiety and stress. The rates of depression, anxiety and stress were highest among those working in COVID wards and emergency care centers, among young workers under 26 years of age, and among workers with disabilities and frequently ill workers. Conclusions: Protecting healthcare workers’ physical and mental health and work ability is a matter of primary importance, particularly under challenging working conditions such as the COVID-19 epidemic.

Chemical Composition and Lipid Bioactive Components of Centaurea thracica Dwelling in Bulgaria.

Centaurea thracica (Janka) Hayek is a plant common in southern Bulgaria. The inflorescences were collected during June and September 2021, while their seeds were obtained in September 2021. The chemical and lipid composition of the inflorescences during the vegetation process of the plant were established. A significant decrease in total proteins (from 8.7 to 7.4%), glyceride oils (2.0-1.7%), and ash (4.5-4.2%) content was observed, while the amount of carbohydrates (72.3-77.2%) and fibers (28.7-35.8%) increased. During the vegetation of the plant, the content of oleic and linoleic acids increased up to 2-3 times, while the level of palmitic acid decreased. The lipids from the seeds were rich in oleic (53.0%) and palmitic (36.2%) acids. The tocopherol content in the oils of the inflorescences during vegetation increased from 58 to 110 mg/kg, and the content in the oil from the seeds was 260 mg/kg. The phospholipid content decreased during vegetation, and differences were observed in the composition between the inflorescences and the seeds. The high content of oleic acid, linoleic acid, tocopherols, and phospholipids determine the nutritional and biological value of the oils isolated from Centaurea thracica, and contribute to their potential use in various directions.

TBE In Bulgaria

First cases of probable tick-borne encephalitis (TBE) were reported in 1961 by Andonov et al. in eastern regions of Bulgaria.1 Possible TBE cases with the typical two-wave fever, originating from consumption of raw goat milk, were described back in 1953 by Vaptzarov et al. in southern Bulgaria.2 Investigations in the 1960s were able to isolate 3 tick-borne encephalitis virus (TBEV) strains from Haemaphysalis punctata and 1 from Dermacentor marginatus ticks from goats and sheep in the district of Plovdiv.3 The antigenic properties of these 4 virus strains were identical to the highly virulent strain “Hypr” of the European subtype of TBEV (TBEV-EU).3

Seroprevalence of West Nile Virus among Equids in Bulgaria in 2022 and Assessment of Some Risk Factors.

The aim of this study was to analyze the seroprevalence of West Nile virus (WNV) among equids in Bulgaria, confirm the results of a competitive ELISA versus the virus neutralization test (VNT) and investigate some predisposing factors for WNV seropositivity. A total of 378 serum samples from 15 provinces in northern and southern Bulgaria were tested. The samples originated from 314 horses and 64 donkeys, 135 males and 243 females, aged from 1 to 30 years. IgG and IgM antibodies against WNV protein E were detected by ELISA. ELISA-positive samples were additionally tested via VNT for WNV and Usutu virus. Thirty-five samples were WNV-positive by ELISA (9.26% [CI = 6.45-12.88]), of which 15 were confirmed by VNT; hence, the seroprevalence was 3.97% (CI = 2.22-6.55). No virus-neutralizing antibodies to Usutu virus were detected among the 35 WNV-ELISA-positive equids in Bulgaria. When compared with VNT, ELISA showed 100.0% sensitivity and 94.5% specificity. A statistical analysis showed that the risk factors associated with WNV seropositivity were the region (p < 0.0001), altitude of the locality (p < 0.0001), type of housing (p < 0.0001) and breed (p = 0.0365). The results of the study demonstrate, albeit indirectly, that WNV circulates among equids in northern and southern Bulgaria, indicating that they could be suitable sentinel animals for predicting human cases and determining the risk in these areas or regions of the country.

ОПТИМИЗАЦИЯ ОБРЕЗКИ ПРИ ВЫСОКОШТАМБОВОЙ ФОРМИРОВКЕ ВИНОГРАДА СОРТА КАБЕРНЕ СОВИНЬОН

The influence of the length of the fruiting canes on the productive capacity of the Cabernet Sauvignon grapevine variety grown on the Umbrella formation in the soil and climatic conditions of southern Bulgaria was studied. The percentage of developed blind buds and fruiting shoots on knots and fruiting canes was found to be highest in variants with pruning for 6 winter eyes and longer with 9 winter eyes, while the trend was reversed for winter eyes allocated above blind bud. The winter eye fertility rate has been shown to be highest in the variant with the longest fruiting canes with 12 winter eyes. The values of this indicator for blind eyes of the fruiting canes decrease slightly with increasing length, while for winter eyes the decreasing order by variant is reversed. The yield per vine and per acre and the mass per bunch were shown to be highest in the variant with pruning of 10 knots of 2 winter eyes and 4 fruiting canes of 9 winter eyes, which under the soil and climatic conditions of the experiment should be preferred.

NONTUBERCULOUS MYCOBACTERIA - CURRENT RISK IN BULGARIA

Background: Nontuberculous mycobacteria (NTM) are generally free-living and have a potential to cause opportunistic infection. More than 190 species of NTM have been identified (http://www.bacterio.net/mycobacterium.html), up to 60 species of them are pathogenic. The distribution is geographically specific for some species and others are cosmopolitan. Understanding their diversity has practical value for the treatment and management of NTM disease. Except for isolated reports, there is no accurate information about NTM spread among Bulgarian patients. Material and Methods: We retrospectively analysed the data on the NTM isolated from patients throughout the country for the period from January 2010 to December 2017. Identification to the species level was done by Line Probe Assay (LPA). Results: 586 NTM strains were identified. We calculated the rate of NTM isolation in Bulgaria and NTM disease incidence by applying microbiological criteria defined by the American Thoracic Society (ATS). As a result, the laboratory isolation rate amounted to 1/100 000 people for the period, and when applying only the ATS criteria, the prevalence of NTM disease was 0,23 per 100 000 people. In both cases, we reported that NTM disease incidence remains low as compared to tuberculosis, though with an increasing trend. The prevalence of NTM varied significantly between northern and southern Bulgaria, as well as between the capital and the rest of the country's regions. Conclusions: Slow growing NTM species predominate in Bulgaria but rapidly growing ones have isolation levels higher than the average for Europe and closer to that of Asian countries. Given the demographic situation in Bulgaria and the changing climatic factors, NTM infections need special attention.

Comparative Technological Assessment of the Quality Formation of Local and Introduced Varieties of Virginia Flue-cured and Burley Tobaccos

The production of “marketable” tobacco is decisive in the pReferences of local farmers towards certain varieties of Virginia and Burley tobaccos. The aim of the study was to complete a comparative technological evaluation of the quality potential of introduced and local varieties of Virginia flue-cured and Burley air-cured tobaccos in Bulgaria. The investigation was conducted with tobaccos from 2018 crop year and included 4 varieties of Virginia flue-cured and 2 varieties of Burley tobacco (local and introduced), grown in different regions of Southern and Northern Bulgaria. The complex assessment of tobacco quality was based on leaf and smoke chemical indicators, external leaf quality elements and smoking performance of the studied tobaccos. The final rating was achieved by referring to the value of the calculated “quality indices”. Two of the local varieties, V 0454 from region Parvomay and PVH 19 from Central Northern Bulgaria were rated the best in the complex evaluation of the FCV tobaccos. A better complex expression of quality was found in the introduced (trial) variety Burley N compared to the local Burley 1317 in Southern Bulgaria region.

Organic vs. Conventional Farming of Lavender: Effect on Yield, Phytochemicals and Essential Oil Composition

Increasing prices and market demand for organic products are stimulants of organic farming. However, this sector is a challenge for producers and further improvements are still necessary. The present study case was conducted to compare the effects of organic (OF) and conventional (CF) farming on lavender (Lavandula angustifolia Mill.) oil yield, plant pigments and essential oil composition. The study was conducted for two years in the period 2019–2020. Six private farms were included in the experiment with conventional and organic agriculture systems. They are located in Kazanlak Valley, Southern Bulgaria. Organic lavender inflorescences were determined to have chlorophyll a and total chlorophyll within a narrow range between 251.3 and 275.7 μg·g−1 and between 375.5 and 487.0 μg·g−1 compared to conventional ones—between 245.9 and 377.5 μg·g−1 and 385.3 and 595.4 μg·g−1 respectively. However, carotenoids and anthocyanins were in a wide range in organic lavender between 36.9 and 72.2 μg·g−1 and 410 and 1240 µg cyn-3-gly.g−1 compared to conventional ones—between 55.5 and 77.3 μg·g−1 and 200 and 780 µg cyn-3-gly.g−1, respectively, for both studied years. The key constituents in essential oil were linalyl acetate (28.42–38.23%), linalool (20.01–31.04%) and β-caryophyllene (7.95–14.97%). The composition was compared with the parameters set out in the international standard for lavender oil. The influence of the type of agricultural system on essential oil yield and its composition was not found. According to the obtained results, levels of chlorophyll a, chlorophyll b and total chlorophyll were higher in conventional farming than in organic farming for the second year of the study.

Blood parameters of adult marsh frogs Pelophylax ridibundus (Amphibia: Ranidae) in rice paddies subjected to intense agrochemical use.

We present the results of an in situ study of a set of blood parameters in adult marsh frogs (Pelophylax ridibundus (Pallas 1771) from populations inhabiting the largest system of rice fields in Bulgaria, the Tsalapitsa rice fields (TRF), under chronic stress conditions. This study was conducted in spring 2022 to assess the health status of TRF frogs compared to that of frogs occupying a reference site (RS). Furthermore, this study also compared the results obtained for the TRF population with those obtained in a study conducted at the exact same location with P. ridibundus individuals in 2013 (Zhelev et al. 2018). This comparison highlights the potential effects of persistent use of agrochemicals (pesticides and fertilizers) on the marsh frogs of later generations. Our results suggest that the general health of marsh frogs in the polluted site (PS) in southern Bulgaria has severely deteriorated. Frogs of both sexes were anemic with weakened immune systems compared to those living in the RS. The long-term use of agrochemicals in the PS affected males to a greater extent than it did females. Statistically significant hypochromia was observed in males, combined with general leukopenia, neutrophilia, lymphopenia, monocytosis, eosinophilia, and higher neutrophil/lymphocyte (N/L) ratios.

Pepper vein mottling virus (PVMV) – нов вирус по тютюна в България

The aim of the present study is to trace the emergence and development of TEV and PVMV, new viruses for tobacco in Bulgaria, in the three varietal groups of Burley, Virginia and Basmi tobacco grown in the central part of southern Bulgaria. During the period 2017-2019, immunological studies were carried out to prove new viruses for tobacco in Bulgaria from the group of potyviruses PVMV and TEV. A kit for serological identification of the French company SEDIAG S.A.S. was used to prove the viruses. To detect TEV, TAS-ELISA was performed with IgG dilution of 1:100 and DAS-ELISA - to detect PVMV with IgG dilution of 1:100. In Virginia and Basmi tobacco variety groups, the potyvirus PVMV was serologically proven, and the virus was identified for the first time in tobacco in Bulgaria. PVMV was demonstrated in monoinfection and in complex with TEV in isolates from the cultivar group Virginia and Basmi. TEV and PVMV were not detected in isolates from the Burley cultivar group. In tobacco, the two potyviruses cannot be distinguished based on symptoms alone. Accurate diagnosis is possible by applying an ELISA or PCR test

Hepatitis E Virus (HEV) Infection among Hemodialysis Patients from Southern Bulgaria.

Viral hepatitis B and C are widely recognized problems in hemodialysis (HD) patients. There have been increasing reports of the importance of the hepatitis E virus (HEV) in recent years, but the worldwide data on the seroprevalence of HEV among them are conflicting. The aim of the present study was to assess the seroprevalence of HEV in HD patients and to analyze the predictors of seropositivity. This study was conducted in 2020 in the central part of southern Bulgaria. A total of 225 patients were enrolled. An enzyme-linked immunosorbent assay for the determination of anti-HEV IgM/IgG was used. All patients were tested for the presence of HEV RNA. Anti-HEV IgM alone and anti-HEV IgG alone were found in 6 (2.7%) and 14 (6.2%) patients, respectively, and in 4 (1.8%) patients, they were found simultaneously. All patients were HEV RNA-negative. The overall HEV seroprevalence was 10.7% (24/225). The binominal logistic regression analysis of available predictors confirmed the role of vascular access and a duration of dialysis treatment over 5 years as predictors significantly associated with increased risk for HEV, and the consumption of bottled water with lower levels of HEV IgG seroprevalence among hemodialysis patients. The accumulated data are the basis for comparative analysis in subsequent trials in the same dialysis centers and for enhancing the range of screening markers used in this particular patient group.

Body condition based on scaled mass index in adult Pelophylax ridibundus (Amphibia: Ranidae) inhabiting a polluted area in Southern Bulgaria

Body condition based on scaled mass index in adult Pelophylax ridibundus (Amphibia: Ranidae) inhabiting a polluted area in Southern Bulgaria

Few dental indices in modern Bulgarian population from southern Bulgaria

AimThe aim of the present study is to evaluate the reduction of the distal teeth towards the medial ones in one functional dental group in southern Bulgarian population.Materials and methodsThe study included 232 Bulgarians aged 20–40 years. Mesiodistal dimensions of the teeth were measured by Dentistry Sliding Vernier Caliper and analyzed with SPSS 23.0. Four interdental indices were calculated: inter-incisive, premolar, upper, and lower molar indices.ResultsWe found a decrease in the percentage ratio of the lateral to the central incisors of people from the Bulgarian population compared to those dating from the Eneolithic period on the territory of Bulgaria. Furthermore, we found a reduction in the percentage ratio of the upper and lower second molars compared to the first ones. The biggest reduction in the percentage ratio (more than 6%) was found in the lower second premolars compared to the first ones, which is characteristic for southern Bulgarians.ConclusionThere was a dental reduction in all the distal members compared to the medial ones participating in one morphological dental group. As a result, we think that interdental indices can be used for explaining historical, cultural, and biological macro and microevolutionary processes and thus for understanding the origin, formation, contacts, and migration pathways of the different populations leading to ethnic variation of humanity. Therefore, they can be a reliable source of information in physiological anthropology.

First report of the occurrence of Pestalotiopsis sp. on blueberry in Bulgaria – morphology and pathogenicity - (short communication)

The cultivation of blueberry (Vaccinium sp.) in Bulgaria has increased in recent years, but the knowledge of its diseases is almost nonexistent. During monitoring for the sanitary status of blueberry crops in Southern Bulgaria (Plovdiv region), symptoms of stem cancer, twigs necrotic lesions, leaf spots and low vigour were observed on 3-year-old Duke cv. Four isolates were obtained from damaged stems and leaves and were single-spored. The isolates were recognized as Pestalotiopsis sp. according to the cultural characteristics of the fungal colony (colony color and the presence of fruiting bodies) and morphological characteristics of conidia (color, length, width, number and size of the apical and basal appendages). In a controlled experiment, the representative isolate was pathogenic to the Duke cv. Based on morphological characteristics and pathogenicity, this study is the first report of the Pestalotiopsis sp. associated with cancer stem and leaf spots on blueberries in Bulgaria.