The East Balkan swine (Sus scrofa) is the only aboriginal pig breed in Bulgaria, and it is indigenous to the eastern part of the country. The aim of the present study was to investigate East Balkan swine (EBS) in Bulgaria for serological evidence of hepatitis E virus (HEV). Sera from 171 swine from two parts of the country (northeastern and southeastern) were tested for anti-HEV IgG antibodies. The overall HEV seroprevalence was 82.5% (141/171), and for weaners it was 77.2% (44/57), for fattening pigs 79.0% (45/57), and for adults 91.2% (52/57). HEV positivity was higher in fattening pigs and adults compared to weaners: OR = 1.108 (95% CI: 0.456–2.692) and OR = 3.073 (95% CI: 1.016–9.294), respectively. This study provides the first evidence of exposure to HEV in EBS from Bulgaria.

Scientific evidence indicates that hepatitis E virus (HEV) infection is a zoonotic disease. Domestic pigs and wild boars are the main animal reservoir for HEV worldwide. The aim of this study was to analyze the seroprevalence of HEV infection among wild boars in western Bulgaria. Serum samples from 240 wild boars from two regions of the country (northwestern and southwestern) were tested for anti-HEV Immunoglobulin G (IgG) antibodies. The overall HEV seroprevalence was 40.8% (98/240); northwestern region 40.0% (48/120); southwestern region 41.7% (50/120). HEV seropositivity in the southwestern region was higher than in the northwestern region: odds ratio = 1.071 (95% confidence interval: 0.640–1.793). This research provided the first seroprevalence study to HEV in wild boars from western Bulgaria.

The hepatitis C virus (HCV)-related bovine hepacivirus (BovHepV) can cause acute as well as persistent infections in cattle. The true clinical relevance of the virus is not yet known. As reliable antibody detection methods are lacking and prevalence studies have only been conducted in cattle and few countries to date, the true distribution, genetic diversity, and host range is probably greatly underestimated. In this study, we applied several RT-PCR methods and a nano-luciferase-based immunoprecipitation system (LIPS) assay to analyze bovine serum samples from Bulgaria as well as wild ruminant sera from Germany and the Czech Republic. Using these methods, BovHepV infections were confirmed in Bulgarian cattle, with viral genomes detected in 6.9% and serological reactions against the BovHepV NS3 helicase domain in 10% of bovine serum samples. Genetic analysis demonstrated co-circulation of highly diverse BovHepV strains in Bulgarian cattle, and three novel BovHepV subtypes within the genotype 1 could be defined. Furthermore, application of a nested RT-PCR led to the first description of a BovHepV variant (genotype 2) in a wild ruminant species. The results of this study significantly enhance our knowledge of BovHepV distribution, genetic diversity, and host range.

Bovine respiratory disease (BRD) is one of the most common and economically important disease affecting feedlot industry throughout the world. The economic significance of this condition are high morbidity and mortality, decreased weight gains, reduced food utilization, low meet quality and additional therapeutic and prophylactic measures. The hypothesis of this study was that the use of metaphylactic protocol based on the risk to develop BRD would reduce morbidity and mortality. For this purpose, the aims of this study were to evaluate the effect of tildipirosin on the incidence of BRD in feedlot cattle. A total of 106 male beef calves were enrolled in the study. Calves were allocated randomly in control group (54 animals) and treatment (52 animals) group. The first group received subcutaneous injection of placebo while the second was treated with SC injection of tildipirosin. The observed BRD incidence was 35.2, and 9.6% for the calves in the control and treatment group, respectively (P = 0.012). These results suggest that the tildipirosin metaphylaxis tend to decrease the incidence of BRD in the first four weeks of the fattening period in beef cattle. In conclusion, metaphylactic protocols, based on the administration of tildipirosin in the high risk period can be used for management of BRD.

Morbidity due to Corynebacterium pseudotuberculosis infection occurred in a 320 Holstein dairy herd in south‐eastern Bulgaria during 2014. All established cases (n=43) were of multiple abscess formation and cellulitis predominantly localised on the hindlegs. The pyogranulomatous and ulcerative lesions in all cases were associated with mastitis. The disease was treated with parenteral antibiotics and local antiseptics, without any satisfactory outcome, and most of the affected animals were culled. Presumptive laboratory diagnosis of C pseudotuberculosis was made in November 2014, when 43 cases (herd prevalence 23.9 per cent) were recorded on the farm. The culling rate reached 95.3 per cent. All reported cases were in first calving cows (n=31; case prevalence 72.1 per cent), and cows between second and fifth lactation (n=12; case prevalence 27.9 per cent). Younger cattle appeared to be less susceptible to the infection. In first calving cows, all cases with lesions and mastitis occurred shortly after calving.