The first case of African swine fever in domestic pigs in Serbia was in 2019. The following year, the disease was confirmed in wild boar. Thenceforth, ASF has been continuously reported in both wild and domestic pigs. The outbreaks in domestic pigs could not be linked directly to wild boars, even though wild boars were endemically infected, and reservoirs for ASF. This study aimed to investigate outbreaks and routes of transmission in domestic pigs in a region of central Serbia where no outbreaks in wild boar were reported. Fourteen outbreaks of ASF on backyard farms with low biosecurity were traced back, and no connection to wild boar was found. The epidemic investigation covered 2094 holdings, with 24,368 pigs, out of which 1882 were tested for ASF. In surrounding hunting grounds, field searches were conducted. Dead wild boars were found, and 138 hunted wild boars were negative for ASFV. It was concluded that outbreaks in 2021 were provoked by the illegal trade of live animals and pig products. Even though infective pressure from wild boars is assumed, no positive cases have been found, while the ASFV spreads within the domestic swine population evidenced in four recent outbreaks in 2022.

African swine fever (ASF) is a highly fatal viral haemorrhagic disease affecting pigs. This study uses official surveillance data to investigate the persistence and spread of ASF in wild boar populations in Serbia from 2020 to 2024. A total of 480 ASF cases were analysed, with spatiotemporal clustering conducted via SaTScan™ and proximity analyses performed in the Quantum Geographic Information System. The yearly prevalence of ASF in wild boar rose steadily from 0.66% in 2020 to 1.47% in 2023. Seasonal trends showed a significant increase in cases during winter (68%) and spring (24%). Five distinct clusters were identified, predominantly near the borders with North Macedonia and Bulgaria, suggesting potential cross-border transmission. Proximity to major roads was significantly associated with ASF case distribution (p < 0.01), while proximity to water bodies and elevation showed no consistent pattern. The findings highlight critical gaps in current passive surveillance systems, which likely underestimate ASF prevalence. The study underscores the need for enhanced surveillance in remote and wooded areas and proposes strategies to improve ASF monitoring and control in wild boar populations. Contribution: This study highlights the feasibility of cost-effective, non-invasive surveillance methods for ASF detection, offering critical insights for low-income countries where resources for intensive disease monitoring are limited. By demonstrating how environmental and anthropogenic factors drive ASF dynamics, this research provides actionable strategies for improving regional and global ASF control efforts.

The bovine respiratory disease complex (BRDC) is multifactorial and results from interactions between host factors, environmental factors, and pathogens. A virus, as an initial pathogen alters the animal?s immunity supporting the bacterial colonization of the lower respiratory tract. Bovine herpesvirus 1 (BHV-1), bovine parainfluenza virus 3 (BPIV-3), and bovine respiratory syncytial virus (BRSV) are among the most significant viruses associated with BRDC. The disease most often affects young and older immunosuppressed animals. Laboratory results depend on the selected sampling site of the respiratory tract and proper timing during the period of virus shedding. The samples for testing mostly include nasal or nasopharyngeal swabs, tracheal wash, bronchoalveolar lavage fluid, or necropsy specimens. Virus isolation, although considered as the gold standard, is time-consuming and depends on the virus species and sampling conditions. Most of the virus identification methods used today are molecular assays (conventional and real-time PCR or RT-PCR) that are rapid, sensitive, and specific, which is of the essence in veterinary diagnostic laboratories. DNA sequencing is mostly used to detect specific genetic mutations and for molecular epidemiology of disease outbreaks. Serological diagnosis is performed based on the detection of specific antibody presence after infection of seronegative animals or a 4-fold specific antibody titer rise in paired serum samples. Different assays are available, including virus neutralization, complement fixation, haemagglutination inhibition, and ELISA. The early and reliable diagnosis is beneficial in the management and control of BRDC and is the basis of a timely treatment and prevention program.

West Nile fever is a vector borne viral disease that can affect humans, horses, birds and sometimes other species of animals. Every year West Nile fever is detected in the human population in Serbia. The disease often occurs in a subclinical form, but most clinically evident cases occur in horses. Therefore, horses are recommended as a sentinel species for monitoring the general incidence of West Nile fever in a specific territory. Our goal was to determine the prevalence of antibodies against West Nile fever virus in horses in the Belgrade epizootiological area. We examined serum samples from 77 horses to determine the seroprevalence of West Nile fever virus in horses throughout the city of Belgrade. Sera were tested by commercial ELISA tests for detection of specific IgG-class antibodies to West Nile fever virus and for the detection of specific IgM-class antibodies to confirm the presence of old and acute (recent) infections in horses. The results confirmed that West Nile fever virus is widespread, detected in 70.1% of the surveyed horse population in Belgrade, and we also detected 5.1% of acute cases had occurred due to horses being infected in 2019. The seroprevalence of West Nile virus in the horse population in the municipality of Belgrade is increasing.

Objectives: Although bluetongue is not a contagious disease, it is easily transmitted and spread by appropriate insect vectors, causing great economic damage. Climate change has led to the fact that vectors and diseases have spread to the top of Northern Europe, causing great economic losses in livestock production. An even greater problem is controlling the disease, because numerous species of domestic and wild ruminants are susceptible to bluetongue. The most effective tool against bluetongue disease is vaccination. Methods: Our goal was to carry out laboratory tests of the starting material and the finished product of the candidate inactivated vaccine against BTV4, and to comment on the obtained laboratory results and the results of previously performed clinical studies. There is no ideal vaccine against the bluetongue virus (BTV) due to the serotype diversity of its strains. Thus, there is a need for a vaccine for at least 24 clinically significant serotypes. Sometimes, it is difficult to obtain the desired amount of vaccine against a defined serotype on the market, and this has led to the need for a new vaccine against bluetongue disease. In this study, we tested an experimental inactivated vaccine against BTV4. The master seed BTV4 was examined and characterized by sequencing. Results: The candidate BTV4 vaccine induced the onset of immunity at the latest at day 21 after the application of the first dose in more than 80% of the vaccinated individuals, while the ELISA test detected specific antibodies against BTV for more than a year. Along with our laboratory results, the preliminary results of safety and efficacy trials are also presented. Conclusions: The side effects of this inactivated BTV4 vaccine are within the limits of permissible local reactions without generalized changes in the health status, while the serology and challenge test leads to the conclusion that this vaccine against BTV4 protects a high percentage of vaccinated individuals against BTV4 or causes a significant reduction in the intensity and duration of the clinical signs in the vaccinated sheep. Based on the trial results, the new vaccine has given encouraging results in terms of quality, safety, and preliminary efficacy tests. Thus, we believe that a new vaccine against BTV is on the horizon.

West Nile fever is a mosquito-borne zoonotic disease caused by West Nile virus (WNV), maintained in an enzootic cycle between avian hosts and Culex mosquitoes. While birds are the principal reservoirs, WNV also infects a wide range of mammals, including humans, horses, and wildlife species. In this study, we assessed WNV seroprevalence in wild ungulates, wild boars, golden jackals, and the invasive rodent nutria in Serbia. A total of 522 serum samples from wild animals were tested. Antibodies against WNV were detected across all tested species, with seroprevalence rates of 37% in wild boars, 11.9% in nutrias, 32.4% in golden jackals, 50.6% in red deer, and 9.1% in roe deer. Detection of antibodies in both adults and juveniles provides evidence of recent transmission during the study period. These findings confirm widespread circulation of WNV in Serbian wildlife and suggest that wild ungulates, carnivores, and invasive rodents may serve as useful sentinel species for monitoring WNV prevalence and geographic spread in natural ecosystems.