Complete genome sequences of two strains of classical swine fever virus of subgenotype 2.3 detected during outbreaks in 2005 and 2006 in Serbia.

Two strains of classical swine fever virus (CSFV) (SRB/CSFV/1264/2005 and SRB/CSFV/6168/2006), producing serious clinical signs of disease during outbreaks in 2005 and 2006 in Serbia, were isolated on porcine kidney cells, and their complete genomes were determined by next-generation sequencing. This first complete genome characterization of Serbian CSFV strains provides new data about the evolution of CSFV in the Balkan region and enables further detailed phylogenetic studies of the various strains.

Epidemiology of human trichinellosis in Vojvodina province, Serbia, from 2005 to 2016.

Trichinellosis is one of the most important foodborne diseases in the Eastern European countries. The main objective of this study was to investigate the epidemiological patterns of trichinellosis outbreaks that occurred between 2005 and 2016 in Vojvodina, a northern province of the Republic of Serbia. The average incidence was 3.5 per 100,000 inhabitants. A total of 828 people acquired the infection. The disease occurred in all age groups, slightly more often in males, and quite frequently in a severe form considering the high share of hospitalised patients and the fatal outcome rate (41.6 ± 31.1% and 0.4%, respectively). Trichinella spiralis was confirmed as the causative agent in eight outbreaks. The outbreaks usually occurred among family members due to the consumption of pork or traditional pork products from not tested backyard pigs. Veterinary control measures and the education of consumers and farmers should be implemented to control this zoonotic disease.

African Swine Fever Outbreak in an Enclosed Wild Boar Hunting Ground in Serbia.

African swine fever (ASF) has been detected in many European countries since its introduction in Georgia in 2007. Serbia suffered its first case of ASF in the domestic pig population in 2019. At the beginning of 2020, ASF was detected in wild boars in open hunting grounds in the southeastern region of the country in districts along the country's borders with Romania and Bulgaria. Since then, all ASF outbreaks in wild boar were clustered in the population located in the same bordering areas. Despite the newly implemented biosecurity protocols for hunters in 2019, ASF was detected for the first time in June 2021 in the wild boar population located in an enclosed hunting ground in the northeast region of the country. In this study, we reported the first ASF outbreak in a wild boar population located in an enclosed hunting ground in close proximity to the Serbian-Romanian border. The epizootiological data on the field investigation of the ASF outbreak, with descriptions of the clinical signs and gross pathological lesions detected, including the total number as well as the estimated age, sex, and postmortem interval, were analyzed. Clinical signs were detected only in nine diseased wild boars, while in total, 149 carcasses were found in the open and enclosed part of the hunting ground. In addition, 99 carcasses from which samples (parts of spleen or long bones) were collected for molecular diagnostics (RT-PCR) were confirmed as ASF-positive. The results of the epidemiological investigations indicate the central role of wild boar movements as well as the constant risk of human-related activities in the countries bordering area.

Risk Factor Impact on African Swine Fever Transmission in Different Extensive Pig Production Settings in Serbia.

The first case of ASF in a domestic pig population in Serbia was confirmed in 2019 in a backyard population. Today, outbreaks in wild boar and, more importantly, in domestic pigs are still occurring, although the government measures for ASF prevention are in place. The aim of this study was to determine critical risk factors and identify the possible reasons for ASF introduction into different extensive pig farms. The study was conducted on 26 extensive pig farms with confirmed ASF outbreaks, with data collected from beginning of 2020 to the end of 2022. Collected epidemiological data were divided into 21 main categories. After identifying specific values of variables as critical for ASF transmission, we identified nine important ASF transmission indicators as those variables for which at least 2/3 of the observed farms reported values critical for ASF transmission. Among them were type of holding, distance to hunting ground, farm/yard fencing, and home slaughtering; however, the hunting activity of pig holders, swill feeding, and feeding with mowed green mass were not included. We represented the data in the form of contingency tables to study associations between pairs of variables using Fisher's exact test. All pairs of variables in the group including type of holding, farm/yard fencing, domestic pig-wild boar contact, and hunting activity were significantly related; hunting activity of pig holders, holding pigs in backyards, unfenced yards, and domestic pig-wild boar contact were observed on the same farms. Free-range pig farming led to observed domestic pig-wild boar contact on all farms. The identified critical risk factors need to be strictly addressed to prevent the further spread of ASF to extensive farms and backyards in Serbia and elsewhere.

Eight-Year Study of Haemogregarina stepanowi Infection in Poached European Pond Turtles (Emys orbicularis) Held in Belgrade Zoo Quarantine.

The eight-year study (2015-2023) was performed on a large sample of poached European pond turtles infected with Haemogregarina stepanowi and held in a pond that belongs to a quarantine section of Belgrade Zoo. The protected species of European pond turtles have been found in poor health, with general weakness, anorexia, and low motility. Comprehensive cytological, hematological, molecular, and postmortem evaluations have been performed. Initially, Diff Quick staining of the blood smears revealed rounded or elongated erythrocytes, often bearing premeront or U-shaped gamont of the hemogregarines inside. The reduced erythrocyte numbers, hemoglobin, and hematocrit values found in the examined population of infected turtles indicated anemia. Macroscopically, shell necrosis and massive skin hemorrhages were the most prominent findings observed in diseased turtles. Microscopically, the lungs, liver, kidneys, and spleen revealed hyperemia, hemorrhages, and the presence of parasitic stages in tissue samples in 31 of 40 necropsied turtles. Cytological and microscopic examination of the samples proved to be sufficient for establishing the infection, but molecular analyses of the 18S sequence were used for phylogenetic studies. Over the years, the number of diseased and dead turtles has decreased, which could be hypothetically attributed to the elimination of leeches as the definitive host.

Study of the genetic variability of porcine circovirus type 2 detected in Serbia and Slovenia.

Recent variants of porcine circovirus type 2 (PCV2) were obtained from tissues of domestic pigs with porcine circovirus associated disease and from randomly selected wild boar samples from Serbia and Slovenia. A 450-base-pair nucleotide sequence was obtained by PCR from the ORF2. The derived nucleotide and amino acid sequences were aligned and compared to the corresponding region of closely related PCV2 sequences determined in previous years and retrieved from the GenBank. The 30 Serbian and 17 Slovenian PCV2 sequences clustered into three previously determined genotypes (PCV2a: 7), (PCV2b: 38) and (PCV2d: 2). Three major variable regions, concerning 29 amino acid position substitutions within the ORF2, were observed, which further supports the segregation of the detected strains into three separate genotypes. This study indicates that PCV2b is the predominant genotype in Serbia and Slovenia and the detected PCV2 strains are closely related to those previously described in Europe and in other parts of the world.

First Report of Sarconema eurycerca Heart Infection in Mute Swans in Serbia.

BACKGROUND: The Sarconema eurycerca heart infection may be one of the main causes of death in swans and geese due to severe heart lesions. To date, there have been no reports of Sarconema eurycerca in mute swans (Cygnus olor) in Serbia and this parasite has never been morphologically characterized in wild birds from this region. METHODS: In spring 2021, eight dead mute swans (Cygnus olor) were collected during avian influenza surveillance on the territory of the Province of Vojvodina and submitted to Scientific Veterinary Institute "Novi Sad" to determine the cause of death. The presence of highly pathogenic avian influenza subtype H5N1 was determined in all swans using molecular methods. RESULTS: Necropsy of the swans revealed changes characteristic for highly pathogenic avian influenza infection, such as severe haemorrhages and necrosis in different organs. Three of the eight swans showed massive subepicardial haemorrhages and myocarditis with intralesional 2-4 cm long whitish roundworms. Histopathologically, haemorrhages and many adult heart worms were observed in the myocardium. Based on morphological features of parasites, infection by Sarconema eurycerca was concluded. CONCLUSION: According to the available scientific literature, the presence of heart roundworms in swans has not yet been confirmed in our country. This report is the first published case of cardiac filariasis associated with S. eurycerca infection in mute swans in the Republic of Serbia.

Susceptibility to Bacteriocins of Multiresistant, mecA Gene Possessing Staphylococcus pseudintermedius Strains from Lesions on Dogs in Vojvodina (Serbia).

Aims: Staphylococci are considered commensal organisms; however, they can also cause diseases in animals. The species Staphylococcus pseudintermedius was originally isolated from the nares and anal mucosa of healthy dogs; nowadays, the incidence of methicillin-resistant S. pseudintermedius strains in dogs has increased, and this species has also become the most common cause of canine skin lesions. S. pseudintermedius were tested for their susceptibility to bacteriocins to show the potential of bacteriocins to eliminate/reduce S. pseudintermedius as a causative agent. Material and Methods: In this study, S. pseudintermedius were isolated from skin lesions on dogs of various breeds and ages in the Vojvodina region (Serbia) in the framework of our international co-operation. Results: S. pseudintermedius strains were identified using matrix-assisted laser desorption ionization time-of-flight mass spectrometry, and the species allocation was confirmed by genotypization and corroborated using phenotyping tests. The strains were multiresistant, involving methicillin-resistance. In addition, the mecA gene was detected in S. pseudintermedius strains, confirming the presence of a genetic feature for methicillin resistance. S. pseudintermedius strains produced large amounts of the enzymes alkaline phosphatase and acid phosphatase; they were low-grade biofilm forming (0.1 ≤ A570 < 1.0), except S. pseudintermedius SPs1. All strains were susceptible to gallidermin (inhibition activity up to 204,800 arbitrary unit [AU]/mL); however, they were mostly resistant to enterocins. However, biofilm-forming S. pseudintermedius SPs1 was susceptible to enterocins (200 AU/mL). Conclusion: Establishing the susceptibility of multiresistant and mecA gene-possessing S. pseudintermedius strains to gallidermin is an innovative, original result; it provides a new opportunity for preventing/eliminating infection caused by those agents.