Porcine cytomegalovirus (PCMV) infection is widespread worldwide and has a high prevalence in swine herds, especially in countries with intensive swine production. PCMV is zoonotic and can impact xenotransplants. It is the third swine virus known to be zoonotic, following swine influenza virus (influenza A) and hepatitis E virus genotype 3 (HEVgt3 or HEV-3). Wild boars, serving as reservoirs for various pathogens, including PCMV, pose a risk to both the pig industry and public health. This study aimed to investigate PCMV infection in Serbian wild boars using real-time PCR and assess other viral infections. We also tested samples for the presence of other viral infections: Aujeszky disease virus (ADV), Porcine parvovirus (PPV) and Porcine reproductive respiratory syndrome (PRRSV). Samples from 50 wild boars across 3 districts were tested. Results showed 8% positivity for PCMV DNA, with females showing higher infection rates. Porcine parvovirus (PPV) was detected in 56% of samples, while Porcine reproductive respiratory syndrome virus (PRRSV) was absent. ADV was found in 18% of samples, primarily in younger animals. This research contributes to understanding PCMV prevalence in Serbian wild boars and emphasizes the importance of monitoring viral infections in wild populations, considering the potential zoonotic and economic implications.

Contrary to pig farming in developed Western countries, in a large part of the world, pigs are still traditionally kept in small backyard farms, usually for family needs. Their main characteristics are low biosecurity, swill feeding, natural breeding and uncontrolled trade. Given the high number of backyard farms in Serbia and the risk they are thought to pose to intensive pig farming, the main aim of this study was to evaluate the prevalence of major viral diseases of swine among traditionally kept pigs in small holdings with low biosecurity. For this investigation, 222 serum samples from 69 backyard holdings were randomly selected and tested for antibodies to Porcine Reproductive and Respiratory Syndrome virus (PRRSV), Aujeszky’s disease virus (ADV), Porcine Parvovirus (PPV) and Swine influenza Virus (SIV) by enzyme-linked immunosorbent assay (ELISA). The herd-level seroprevalence of PRRS, Aujeszky’s disease and PPV was 2.9%, 27.5% and 37.7%, respectively. Swine influenza seroconversion was not confirmed in any of the tested holdings. Despite widely distributed PPV and AD in backyard farms in Serbia, almost 50% of them are still negative for all the tested diseases. The backyard farms must be monitored, and owners must be educated as their role in eradication programs and obtaining country-free status may be crucial.

The implementation of biosecurity measures as the first line of defense is an essential prerequisite for preventing the occurrence and spread of infectious agents in flocks. Assessment of biosecurity measures on the farms was carried out during farm visits based on the application of an appropriate questionnaire whereby the farmer answered a number of questions regarding the implemented biosecurity measures. The study was performed via Biocheck.UGent online survey on 16 broiler farms in the region of the city of Belgrade. The capacity of farms was 25,000-100,000 broilers, placed in 2-4 houses, depending on the farm. Farm visits were made by the authors to confirm the correct answers to the online survey. Results showed that external biosecurity scores ranged from 57% to 93%, averaging 83.6%. Internal biosecurity score ranged from 48% to 98%, with an average score of 85.7%. The total score for the biosecurity assessment ranged from 56% to 93%, with an average score of 84.3%. The scores for subcategories varied between the farms. Removing manure and carcasses, a subcategory within the category of external biosecurity, had the lowest mean score (farms 9 and 10 had a score of 12%). Relatively low scores were also obtained for the number of steps of broilers depopulation (farm 9 had a score of 44%) and for the location of the farm (farms 2 and 3 had a score of 44%). Concerning internal biosecurity, the lowest score was obtained for the subcategory material and measures that they apply between compartments (farm 10 had a score of 29%). These findings should be useful for decision-makers and flock veterinarians and farmers to set feasible targets and sustainable biosecurity programs to improve biosecurity, the health status of the flock, and farm profitability.

Fowl adenovirus infections have a significant economic impact, especially in the production of broilers. It is considered the leading cause of three syndromes: adenoviral gizzard erosions and ulcerations, inclusion body hepatitis, and hepatitis-hydropericardium syndrome. A critical feature of this virus is its immunosuppressive effect, via suppressing humoral and cellular immunity. In this study, we examined the humoral immune response after administration of the Newcastle disease vaccine in broiler flocks with previously confirmed seroconversion against Fowl adenovirus. The study was conducted on 5 farms. A total of 220 chickens, five weeks of age, showing no clinical signs of the disease, were included in this study. The control group consisted of 20 chickens from a negative farm. Chickens were vaccinated with commercially available live NDV vaccines between 11 and 13 days of life. ELISA determined the presence of specific antibodies against FAdV in a total of 130/200 (65%) blood sera. Depending on the farm, seroprevalence ranged from 30-100%. The presence of specific antibodies against NDV was determined three weeks after vaccination using the hemagglutination inhibition assay. A positive hemagglutination inhibition (HI) titer (≥ 16) was found in 41/200 (20.5%) sera, which was significantly less compared to the control farm, where a positive HI titer was found in 20/20 (100%) sera. The results of our study indicate the immunosuppressive effect of FAdV in subclinically infected birds and highlight the need for its diagnosis, prevention, and control.

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.

Contrary to pig farming in developed western countries, in a large part of the world, pigs are still traditionally kept, in small backyard farms, usually for family needs. Their main characteristics are low biosecurity, swill feeding, natural breeding and uncontrolled trade. Given the high number of backyard farms in Serbia and the risk they are thought to pose to intensive pig farming, the main aim of this study was to evaluate the prevalence of major viral diseases of swine among traditionally kept pigs in small holdings with low biosecurity. For this investigation, 222 serum samples from 69 backyard holdings were randomly selected and tested for PRRS, Aujeszky`s disease, PPV infection and Swine influenza by ELISA. The herd-level seroprevalence of PRRS, Aujeszky`s disease and PPV infection was 2.9%, 27.5% and 37.7%, respectively. Swine influenza seroconversion was not confirmed in any of the tested holdings. Despite widely distributed PPV and AD in backyard farms in Serbia, almost 50% of them are still negative for the all-tested disease. The backyard farms must be monitored, and owners educated as their role in eradication programs and obtaining country-free status may be crucial.