Serological Examinations of Significant Viral Infections in Domestic Donkeys at the Special Nature Reserve "Zasavica", Serbia

The paper presents the findings of specific antibodies in the blood sera of donkeys against the following viruses: equine infectious anemia virus (EIAV), African horse sickness virus (AHSV), equine herpesvirus type 1 (EHV-1), equine influenza virus subtype H3N8 (EIV) and equine arteritis virus (EAV). The analyses were conducted during the year 2022. From a total of 199 donkeys bred in "Zasavica", blood was sampled from 53 animals (2 male donkeys and 51 female donkeys), aged 3 to 10 years. Specific antibodies against EIAV were not detected in any of the tested animals using the agar-gel immunodiffusion (AGID) assay. No specific antibodies against AHSV, tested by enzyme-linked immunosorbent assay (ELISA), or antibodies against EAV, tested by the virus neutralization test (VNT) and ELISA were detected in any of these animals. A positive serological result for EHV-1 was determined by the VNT in all animals, with antibody titer values ranging from 1:2 to 1:128, while a very low antibody titer value for EIV (subtype H3N8) of 1:16 was determined in 18 donkeys using the hemagglutination inhibition test (HI test).

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.

Donkey Milk: An Overview of its Chemical Composition and Main Nutritional Properties or Human Health Benefit Properties

The donkey milk has a remarkable similarity to human milk, in addition to its valuable nutritional composition and content of numerous immune factors. The donkey milk is the subject of research worldwide, and data from the literature suggest significant differences with respect to the contents of individual components. However, some basic characteristics of donkey milk have been established: low contents of fat and cholesterol, total proteins and casein and high contents of lactose, whey proteins, calcium, selenium, and Vitamin D3. The donkey milk is rich in various protective proteins (α-lactalbumin, lysozyme, lactoferrin, lactoperoxidase, and immunoglobulins), and shows strong antioxidant, antibacterial, antiviral, antifungal, hypoglycemic, antiparasitic, and antitumor activity. Donkey milk can be considered functional food, having in mind that its fatty-acid profile and content of essential fatty acids are beneficial for cardiac health. The total fat content in donkey milk is low compared to human milk, and for this reason it is necessary to enrich donkey milk with other fat in order to provide enough calories in a diet for children. Commercialization of donkey milk and dairy products is still limited due to low production levels, that is lack of products on the market, and lack of product information. Considering the research data from the literature, there is a need for human clinical trials in order to obtain a stronger evidence of the therapeutic properties of donkey milk.

HONEYBEE VIRUSES PRESENCE IN SERBIAN APIARIES: A REVIEW

The honey bee Apis mellifera is an important beneficial insect recognized by production of honeybee products, having an important role in agricultural production through pollination, and play an equally crucial role in conserving the biodiversity in many natural ecosystems. According to available literature data, in the last more than 20 years, dramatic honey bee winter colony losses have been reported frequently all over the world that could have a direct influence on human food resources and can affect not only apiculture or agriculture, but also has an anthropological threats. One among many reasons for global bees-decline phenomenon is the influence of many viruses on honeybees’ health. Until today, in total, 36 viruses is detected in honey bees, and for many of them still without known pathogenicity on honeybees’ health. However, it is well known that some of these viruses like Acute Bee Paralysis Virus (ABPV), Chronic Bee Paralysis Virus (CBPV), Deformed Wing Virus (DWV), Black Queen Cell Virus (BQCV), Sacbrood Virus (SBV), Kashmir Bee Virus (KBV), Israeli Acute Paralysis Virus (IAPV), Slow bee paralysis virus (SBPV), Varroa destructor virus (VDV1) and some others has direct or indirect influence on individual honeybee or on whole honeybees colony health. In this paper the review of existing literature data on the presence, prevalence and characterization of honeybee viruses detected in honeybee colonies and apiaries from different regions in Serbia from first detection of their presence in 1986 till nowadays is presented and discussed.

QUALITY OF WELL WATER INTENDED FOR WATERING PIGS: ANALYSES OF BACTERIOLOGICAL PARAMETERS AND PESTICIDE CONTENT

Water used for watering pigs, originating from five wells located in households in a settlement in Vojvodina, was inspected for its quality by the analysis of bacteriological parameters and pesticide content. Five samples were taken from each well at monthly intervals (n=25). In all water samples from three wells, coliform bacteria, including thermotolerant coliforms and Escherichia coli, indicators of faecal contamination, were repeatedly detected. In the water of all of the five wells organophosphate pesticides were detected, whose maximum allowed concentrations are not defined by the current Serbian Regulations on the quality of drinking water. Given the quantity of water consumed by pigs on a daily basis, water contaminated with coliform bacteria and organophosphate pesticides poses a risk to their health. Diminishing natural resources of drinking water and the growing environmental pollution, renders the assessment of the quality of water intended for domestic animals necessary as part of the integrated system of management in agricultural holdings.  

Coalescence, crystallographic orientation and luminescence of ZnO nanowires grown on Si(001) by chemical vapour transport

We analyse the morphological, structural and luminescence properties of self-assembled ZnO nanowires grown by chemical vapour transport on Si(001). The examination of nanowire ensembles by scanning electron microscopy reveals that a non-negligible fraction of nanowires merge together forming coalesced aggregates during growth. We show that the coalescence degree can be unambiguously quantified by a statistical analysis of the cross-sectional shape of the nanowires. The examination of the structural properties by x-ray diffraction evidences that the nanowires crystallize in the wurtzite phase, elongate along the c-axis, and are randomly oriented in plane. The luminescence of the ZnO nanowires, investigated by photoluminescence and cathodoluminescence spectroscopy, is characterized by two bands, the near-band-edge emission and the characteristic defect-related green luminescence of ZnO. The cross-correlation of scanning electron micrographs and monochromatic cathodoluminescence intensity maps reveals that: (i) coalescence joints act as a source of non-radiative recombination, and (ii) the luminescence of ZnO nanowires is inhomogeneously distributed at the single nanowire level. Specifically, the near-band-edge emission arises from the nanowire cores, while the defect-related green luminescence originates from the volume close to the nanowire sidewalls. Two-dimensional simulations of the optical guided modes supported by ZnO nanowires allow us to exclude waveguiding effects as the underlying reason for the luminescence inhomogeneities. We thus attribute this observation to the formation of a core-shell structure in which the shell is characterized by a high concentration of green-emitting radiative point defects as compared to the core.

AUJESZKY’S DISEASE IN A DOG - CASE REPORT

This article reports on the occurrence and diagnosis of Aujeszky’s disease in a dog. The procedure for isolation and identification of Aujeszky’sdisease virus was described. A dog of unknown breed aged about two years died of Aujeszky’s disease after consuming animal offal (internal organs: lungs, spleen, kidneys) fed by the owner after slaughtering piglets and preparing meat for cooking. As early as 24 hours after consuming the offal, the dog manifested characteristic symptoms of Aujeszky’s disease, which were immediately recognized by the veterinarian. The death occurred within less than 24 hours upon first clinical signs of disease. Aujeszky’s disease virus was isolated and identified from brain and internal organ (lung and spleen) samples of the dog at the Department of Virology of the Scientific Veterinary Institute „Novi Sad“. Isolation and identification of the virus was performed on PK-15 porcine kidney cell line and using nested PCR technique.

Flaviviruses at the territory of Serbia – present situation and challenges

The aim of this study is to summarize the data on the occurrence, presence and prevalence of some zoonotic flaviviruses, which have been actively circulating in the territory of the Republic of Serbia during past decade. The genus Flavivirus, family Flaviviridae,encompasses vector-transmitted viruses with zoonotic potential. The genus is comprised of more than 70 viruses transmitted to humans by mosquitoes and ticks. Some of those are associated only with human diseases (such as yellow fever and dengue fever), whereas others can cause diseases in both humans and animals. Animals are major reservoirs and primary hosts for the latter group. The virus transmission to other animal species or humans occurs via diverse vectors – mostly mosquitoes and ticks. A range of these virus species is widely distributed worldwide, especially in tropical and sub-tropical climatic zones. Some representatives of these species have only recently been identified at the territory of Republic of Serbia. This paper gives an evidence on the presence and distribution of West-Nile virus, tick-borne encephalitis (TBE) virus and Usutu virus that were conducted within the study in Serbia. The research pointed out the presence of recently detected West-Nile virus and Usutu virus as well as the current circulation of tick-borne encephalitis virus, for which only limited serological evidence on the presence of virus-specific antibodies in humans was available so far. In the aspect of public health, the full understanding of the importance of identification and prevalence of different flaviviruses still require further comprehensive entomologicalacarological, seroepidemiological, clinical and virological research. 

Methodology and results of integrated WNV surveillance programmes in Serbia

Studies conducted during the past few years have confirmed active West Nile virus (WNV) circulation in Serbia. Based on these studies and the epidemiological situation, the Veterinary Directorate of the Ministry of Agriculture and Environmental Protection launched national WNV surveillance programmes in 2014 and 2015. The programmes encompassed the territory of Serbia and were conducted by the veterinary service in collaboration with entomologists and ornithologists. The objective of the programmes was early detection of WNV and timely reporting to the public health service and local authorities to increase both clinical and mosquito control preparedness. The WNV surveillance programmes were based on direct and indirect surveillance of the presence of WNV by the serological testing of initially seronegative sentinel horses and chickens as well as through viral detection in pooled mosquito and wild bird samples. The most intense WNV circulation was observed in all seven districts of Vojvodina Province (northern Serbia) and Belgrade City, where most of the positive samples were detected among sentinel animals, mosquitoes and wild birds. The West Nile virus surveillance programmes in 2014 and 2015 showed satisfactory results in their capacity to indicate the spatial distribution of the risk for humans and their sensitivity to early detect viral circulation at the enzootic level. Most of the human cases were preceded by the detection of WNV circulation as part of the surveillance programmes. According to the existing data, it can be reasonably assumed that WNV infection, now an endemic infection in Serbia, will continue to present a significant problem for the veterinary service and public health.

INVESTIGATION OF MYCOPLASMA SYNOVIAE SEROPREVALENCE IN BROILER BREEDER FARMS IN SOUTH BAČKA REGION

Mycoplasma synoviae is known to cause respiratory disorders, synovitis, subclinical infections, air sacculitis and eggshell apex abnormalitiesin domestic poultry worldwide. Th e aim of this study was to determine M.synoviae seroprevalence in 5 diff erent broiler breeder farms in South Bačka from 2014 to 2017. A total of 1511 samples were tested using commercial indirect enzyme linked immunosorbent assay (ELISA) for detection of antibodies in the blood sera. In this study, the seroprevalence of 25.21% was found and 47 (40.87%) fl ocks out of 115 tested were positive to M.synoviae. Seroprevalence varied between 31.02% in 2015 and 16.78% in 2016. Flock prevalence ranged from 31.03% in 2014 to 55.88% in 2015. Th ese results suggest that M. synoviae infection is present in broiler breeder farms in South Bačka, and that is necessary to conduct further research, systematic monitoring and to improve biosecurity measures on broiler breeder farms.

Serological evidence of equine arteritis virus infection and phylogenetic analysis of viral isolates in semen of stallions from Serbia

Background

Equine arteritis virus (EAV) is responsible for infections in equids. It can spread easily within the horse population and has a major impact on the horse breeding industry. No EAV outbreak has ever been reported in Serbia. To determine whether EAV is nonetheless circulating there, especially in the Vojvodina region, 340 horse serum samples were subjected to serology testing to detect EAV antibodies. In parallel, semen samples from three seropositive stallions were collected to evaluate their EAV status, using RT-qPCR and virus isolation on cell culture.

Results

Horse sera with EAV antibodies represented 15.88% (54/340) of the tested samples, 83.23% (283/340) being negative, and just three samples (0.89%) being uninterpretable due to cytotoxicity. Only 7.2% (10/138) of horses kept by private owners on their own property were seropositive for EAV, whereas 21.8% (44/202) of horses kept on stud farms had EAV antibodies. Phylogenetic analysis showed that the Serbian EAV isolate was most closely related to isolates from the neighbouring Hungary.

Conclusions

EAV is circulating in the Serbian horse population, especially among the breeding population certainly due to the use of EAV shedder stallions since there is no surveillance programme in Serbia and only limited checks on racehorses. Moreover, phylogenetic analysis indicates that the EAV isolated from a Lipizzaner stallion in Serbia is closely related to isolates from Hungary, and together form a new cluster.

First Detection and Clinical Presentation of Porcine Epidemic Diarrhea Virus (Pedv) in Serbia

During 2015/2016, fecal and intestinal samples from live diseased and/or dead pigs with suspected PEDV and/or TGEV and signs of rotavirus infection were collected from in total seven different farrow-to-finish swine farms located in Northern Serbia region (Vojvodina Province). A total of 14 samples (2 pools per farm) of small intestine with fecal content were submitted to laboratory molecular investigation (multiplex RTPCR). On these farms the clinical signs included the occurrence of diarrhea in suckling and weaned piglets, with weak or no response to the applied antimicrobial therapy. The epidemic of severe diarrhea affecting pigs of all ages on one farrow-to finish swine farm was detected in January 2016. Watery diarrhea in all swine categories was associated with vomiting and a reduction in feed consumption. Diarrheic, gaunt and dehydrated piglets, covered with feces were found in 90% litters. The disease affected most severely the suckling piglets, and the mortality in newborn piglets was up to 35%. In the weaned piglets and fatteners the mortality was up to 2.5% and 1.2%, respectively. The PEDV RNA was detected in pooled feces and samples of small intestines derived from diseased and dead suckling piglets from only one investigated farm. The PEDV positive samples showed to be negative for rotavirus group A and TGEV. The transport vehicles were identified as the main possible route of PEDV introduction. This is the first report demonstrating the presence of PEDV in Serbia.

COMPARATIVE ANALYSIS OF DIFFERENT STRATEGIES FOR THE CONTROL OF CLASSICAL SWINE FEVER IN THE REPUBLIC OF SERBIA USING MONTE CARLO SIMULATION

Several diff erent strategies for control and eradication of Classical Swine Fever (CSF) were compared using a Monte Carlo method-based simulationmodel. Th e control strategy analyzed in this paper, in addition to other CSF control measures, includes application of biosecurity measures on pigfarms and rural backyard holdings. Elements of the control strategy are based on applicable regulations and include the simulation of detection ofthe disease, setting up the protected and surveillance zones, standstill of pig movements and restricted movement of animals, vehicles, equipment, and people with strong control measures in protection and surveillance zones, euthanasia of susceptible pigs, protective vaccination of pigs, compensation etc. During the simulation, diff erent output parameters were compared such as: duration of epizootic of a disease, number of aff ected holdings and animals, direct costs such as those for dead or culled animals, costs of surveillance, disposal of infectious materials, cleaning and disinfection.Depopulation of aff ected animals with early diagnostics and vaccination in protection and surveillance zone proved to be the most eff ective measures to stop spreading and eradication of the disease. However, during the simulation, systematic implementation of biosecurity measures in all pig production clusters demonstrated to be appropriate strategy for sustainable control of CSF and setting up a stable epizootiological situation.

PROSPECTIVES AND NECESSITY OF ERADICATION OF INFECTIOUS BOVINE RHINOTRACHEITIS / INFECTIOUS PUSTULAR VULVOVAGINITIS IN THE REPUBLIC OF SERBIA

Infectious bovine rhinotracheitis/infectious pustular vulvovaginitis (IBR/IPV) is a disease aff ecting cattle population of all breeds, categories and age. Th e disease can take diff erent clinical courses, infectious bovine rhinotracheitis (IBR) and infectious pustular vulvovaginitis (IPV) being the most common ones. Both diseases, an especially infectious bovine rhinotracheitis (IBR), pose severe health threat and cause major economic losses and are considered one of the most costly diseases in cattle industry. The causal agent is a virus categorized into the family Hepesviridae and designated as bovine herpesvirus type 1 (BHV-1) or IBR/IPV virus. Any positive result to IBR/IPV specifi c antibodies in non-vaccinated cattle, in either blood or milk, indicates the infection, and the animal is considered a source of infection. In this article, we described the needs and prospects for the eradication of IBR/IPV in the Republic of Serbia. The eradication of IBR/IPV is a complex process implying strictly defi ned program of measures. The implementation of such measures requires systematic strategy involving diff erent phases and activities that can continue over several years. The program requires substantial eff orts as well as fi nancial resources, which should be justifi ed and paid off through a successful eradication of IBR/IPV.

West Nile virus 'circulation' in Vojvodina, Serbia: Mosquito, bird, horse and human surveillance

Efforts to detect West Nile virus (WNV) in the Vojvodina province, northern Serbia, commenced with human and mosquito surveillance in 2005, followed by horse (2009) and wild bird (2012) surveillance. The knowledge obtained regarding WNV circulation, combined with the need for timely detection of virus activity and risk assessment resulted in the implementation of a national surveillance programme integrating mosquito, horse and bird surveillance in 2014. From 2013, the system showed highly satisfactory results in terms of area specificity (the capacity to indicate the spatial distribution of the risk for human cases of West Nile neuroinvasive disease - WNND) and sensitivity to detect virus circulation even at the enzootic level. A small number (n = 50) of Culex pipiens (pipiens and molestus biotypes, and their hybrids) females analysed per trap/night, combined with a high number of specimens in the sample, provided variable results in the early detection capacity at different administrative levels (NUTS2 versus NUTS3). The clustering of infected mosquitoes, horses, birds and human cases of WNND in 2014-2015 was highly significant, following the south-west to north-east direction in Vojvodina (NUTS2 administrative level). Human WNND cases grouped closest with infected mosquitoes in 2014, and with wild birds/mosquitoes in 2015. In 2014, sentinel horses showed better spatial correspondence with human WNND cases than sentinel chickens. Strong correlations were observed between the vector index values and the incidence of human WNND cases recorded at the NUTS2 and NUTS3 levels. From 2010, West Nile virus was detected in mosquitoes sampled at 43 different trap stations across Vojvodina. At 14 stations (32.56%), WNV was detected in two different (consecutive or alternate) years, at 2 stations in 3 different years, and in 1 station during 5 different years. Based on these results, integrated surveillance will be progressively improved to allow evidence-based adoption of preventive public health and mosquito control measures.

PROPOSAL OF A PROGRAM FOR CONTROL, SUPPRESSION AND ERADICATION OF BOVINE VIRAL DIARRHEA VIRUS INFECTION IN CATTLE HERDS IN THE REPUBLIC OF SERBIA

Bovine Viral Diarrhoea (BVD) is a viral infection of cattle caused by Bovine Viral Diarrhoea Virus (BVDV). Th e most important source of infectionis persistently infected and sick cattle, but also other susceptible species. BVDV infection, except for cattle, occurs in sheep, pigs, goats and wild ruminants. Th ese animals can be reservoirs of the virus, and thus the source of infection. Th e greatest economic losses caused by BVDV infectionin cattle farming are the direct consequences of transplacental infection, as a result of foetal deaths, congenital malformations, neonatal and postnatal mortality, including mucosal diseases and slow growth and poor performance results of the surviving animals, as well as acute infections of respiratory and alimentary infections. Economic losses due to BVDV infection can be seen in a cattle herd even several years aft er the infection. Moreover, BVDV infection is considered as the third most important disease to cattle farming industry, immediately aft er rinderpest and the foot-and-mouth disease. Th e primary task of BVDV infection control is to prevent prenatal infection. This procedure includes the determination and elimination of persistently infected (PI) animals from the herd. Aft er the removal of these animals, great attention must be paid to introducing new animals into the herd and preventing the occurrence of transplacental infection. On the basis of existing data and real suppositions about the distribution of BVDV infection in the territory of Serbia, the great economic damages it causes, as well as the general tendency to resolve problems in European states, and for the competitiveness of our farmers and food industries in the production of milk, meat or breeding material after joining the EU market, it is necessary to draft legal regulations in the control of this bovine viral disease in Serbia. The mentioned control could be based on the voluntary BVDV eradication program on herd’s level in the beginning and on establishing herds with BVDV free status. Certifi cation of BVDV free status of herd will be done by Veterinary Directorate, and the register of herds with BVDV free status could be “on line” available and maintained by the Veterinary Directorate. The essence of this proposal, a volunteer program of establishing herds with BVDV free status, is based on several steps or phases, which includes frequent diagnostic testing, removal of PI animals from the herd and the introduction of strict biosecurity measures.

Presence of Human and Animal Viruses in Surface Waters in Vojvodina Province of Serbia

For the first time in Serbia, a small surveillance study was conducted in order to estimate the presence and frequency of occurrence of selected human [adenoviruses (HAdV), noroviruses, (NoV GI, NoV GII) and hepatitis A virus (HAV)], animal [porcine adenovirus (PAdV) and bovine polyomavirus (BPyV)] and zoonotic [hepatitis E virus (HEV)] viruses in selected surface waters. In total, 60 surface water samples were collected in two sampling occasions at 30 locations, with each sampling time being separated by 1-5 months. In addition, six sewage effluent samples were collected at one sampling site per each of the three tested town sewage systems, in two sampling occasions with 2 months intervals, before their discharge into the surface waters. The most prevalent virus found was HAdV which was detected in 43.33 % samples. NoV GII was found in 40 % samples. NoV GI was found in 10 % samples, and PAdV, BPyV and HEV were detected in 5 (8.33 %), 4 (6.67 %) and 2 (3.33 %) samples, respectively. HAV was not found in any of analysed surface waters or urban sewage samples. The obtained results confirm the presence of pathogenic enteric viruses of both human and animal origin in surface waters in Serbia indicating the existence of diverse contamination sources.

West Nile virus serosurveillance in pigs, wild boars, and roe deer in Serbia

West Nile virus (WNV) is maintained in nature in an enzootic transmission cycle between birds and mosquitoes, but it also infects many other vertebrates, including humans and horses, in which it can induce severe neurological diseases; however, data about virus circulation in other mammals is scarce. WNV has a history of recent outbreaks in Europe, including Serbia, where it was identified for the first time in 2010 in mosquitoes and in 2012 in birds and humans, being responsible for over 300 confirmed human cases and 35 deaths there along 2013. To assess WNV circulation among mammals in the country, 688 samples obtained from 279 farm pigs, 318 wild boars, and 91 roe deer were investigated for the presence of antibodies to WNV by enzyme-linked immunosorbent assay (ELISA) and viral neutralization test (VNT), and the specificity of their reactivity was assayed against Usutu virus (USUV). ELISA-reactive sera were identified in 43 (15.4%) pigs, 56 (17.6%) wild boars, and 17 (18.7%) roe deer. Of these, 6 (14%), 33 (59%), and 4 (23.5%) respectively, neutralized WNV. One out of the 45 ELISA negative sera tested, from a roe deer, neutralized WNV. Cross-reactivity neutralization test indicated that all deer and pigs neutralizing sera were WNV specific, while in 5 (15.2%) of the wild boar samples the specificity could not be established. Four wild boar sera showed USUV specificity. All these data confirm the circulation of both flaviviruses in Serbia, and highlight the need for the implementation of global coordinated surveillance programs in the region.

WEST NILE VIRUS SURVEILLANCE PROGRAM IN SERBIA

Serological and virological examination of the presence of human and animal infection caused by West Nile Virus (WNV) as well as the presence of the virus in vectors, which has been conducted during the past few years, confi rmed an active virus circulation in the territory of the Republic of Serbia. Based on the obtained results and anticipated intense circulation of WNV, which poses substantial risks for both public and animal health in Serbia, and having in mind its crucial role in the protection of public health, Veterinary Directorate of the Ministry of Agriculture and Environmental Protection infront the Veterinary Service launched and funded the national WNV monitoring program starting from April 2014. The Program encompassed the entire territory of the Republic of Serbia and was conducted by scientific and specialized veterinary institutes and fi eld veterinary service in close collaboration with qualifi ed entomologists and ornithologists. The principal objective of the monitoring – surveillance program is early detection of WNV in monitored regions, timely reporting of the virus presence and activation of human health service institutions and local authorities aimed at establishing the control measures - eradication of mosquitoes, informing the local community and taking all relevant preventive measures for human health protection. Th e surveillance program of the WNV occurrence and spread is based on direct and indirect surveillance of WNV in natural environment. Indirect surveillance encompasses serological testing of seronegative sentinel horses and poultry for the presence of WNV infection, and it is performing continuously and periodically during the most intensive mosquito activity (May – September). The number of sentinel animals that should be tested was defi ned at the district level, according to the rate of anticipated risk of WNV infection. Direct surveillance was performed through periodical and continuous testing of pooled mosquitoes samples collected at two-week intervals during peak mosquito season (May – September) and samples of wild birds (tissues of dead birds and throat swabs of captured live susceptible bird species). The number of samples was stipulated according to the anticipated risk rate in particular regions.

PREVENTION OF CLASSICAL SWINE FEVER SPREADING IN CROSS-BORDER REGION THROUGH IMPROVEMENTS OF SANITARY STANDARDS AND EDUCATION OF FARMERS

This paper describes the implementation of the project “Prevention of CSF spreading in the cross-border region through improvements of sanitary standards and education of farmers - STOP CSF” implemented and funded under the IPA Cross-Border Programme Croatia-Serbia 2007-2013. The project had been implemented in Serbia by Scientifi c Veterinary Institute “Novi Sad” from Novi Sad and the project partners in the Republic of Croatia were Osjek-Baranja County and the Regional Developmental Agency of Slavonia and Baranja Ltd from Osijek. Th e project was implemented in the period 17 January 2011 - 17 July 2012 (18 months). All planned project activities have been fully implemented. A promotional leaflet was designed, edited and printed in 10000 copies (5000 copies in Serbian and 5000 copies in the Croatian language). On the territory in Serbia where the project was carried out (Southern Backa and Srem district) all of the copies of leaflets printed in Serbian language were distributed. Th e Manual “The prevention of classic swine fever (CSF) in rural farms” of authors, Sava Lazić, Tamaš Petrović, Jasna-Prodanov Radulović and Radoslav Došen, was also edited and printed in 4000 copies (2000 on Serbian and 2000 on the Croatian language). On the territory in Serbia where the project was carried out all the copies of the manual printed in Serbian language were distributed. On the topic of CSF, 10 workshops have been held, visited by 237 participants in Serbia and 4 joint workshops have been held (two in Serbia and two in Croatia) for farmers both from Serbia and Croatia with the total of 84 farmers attended (43 from Croatia and 41 from Serbia). Therefore the workshops in Serbia were attended by 278 participants. For better education and training for implementation of biosecurity measures in the prevention of CSF, in the period from the 21st to the 26th of November 2011 there was organized a study tour to Vehta (Bremen) in Germany. On the study tour, there were 15 farmers and 4 members of the Project team from Serbia, and 15 farmers with 3 members of the Project team and an interpreter from Croatia. In the area of project implementation in Serbia, on family farms, there were 18 disinfectant barriers built. A cost-benefi t analysis was made that scientifi cally and professionally determined that the invested funds are multi functional and instrumental in the prevention of CSF. Th e fi lm „Preventing the CSF in rural households“ (30 min. long) and a TV spot (60 seconds long) were made. Th ey have been broadcasted on over 10 local TV stations. The peak point of project activities was the International Conference: “Preventing the spread of CSF in the border region of Croatia-Serbia (STOP-CSF)” which was held on the 7th and 8th of June 2012 in Novi Sad. At the conference 25 scientifi c and professional papers were presented by the speakers from Germany (EU Reference Laboratory for CSF), by high scored professionals from the neighbouring countries (Italy, Slovenia, Austria, Romania, Hungary, Bulgaria, Macedonia, and Bosnia and Herzegovina) and the countries where the project was implemented (Croatia and Serbia). The first day of the Conference there were 152 participants, and 158 on the second day, mainly veterinarians. Th e general impression was that the Conference was successful, the lectures and discussions provided explanations on many issues from epizootiological surveillance, prevention and diagnostics of Classical Swine Fever (CSF).

POTENCY TEST OF COMMERCIALLY AVAILABLE INACTIVATED NEWCASTLE DISEASE VACCINES IN SERBIA

In order to evaluate the efficacy of inactivated oil-emulsion Newcastle disease vaccine (commercially available on market in Serbia) we carried out the potency test in chickens, using hemagglutination inhibition (HI) test for detection of antibodies. Th e values of HI titers in the serum before and three weeks aft er vaccination revealed immunoconversion (IC) in chickens, and indicated potential diff erences in the immunoconversion values between two groups vaccinated with monovalent and polyvalent vaccine. In the period 2010-2012, 27 vaccines were tested, there of 21 polyvalent and six monovalent ones. Th ree weeks aft er the vaccination, HI titers of all vaccines were high. Th e average IC values were calculated as log2 (HI titer). The values ranged from 2.2 to 8.2 for polyvalent vaccine, whereas average values for monovalent vaccines were in the range from 3.2 to 6.3. Three weeks post vaccination; no statistically signifi cant diff erences were recorded in the immune response between the tested groups of birds (vaccinated with monovalent and polyvalent vaccines). This supports the fact that both tested vaccines demonstrated good potency to creating immunity against ND in vaccinated birds.

DETERMINATION OF AZOXYSTROBIN AND DIFENOCONAZOLE IN PESTICIDE PRODUCTS

In this study a high performance liquid chromatographic (HPLC-DAD) procedure has been developed for the simultaneous determination of azoxystrobin and difenoconazole in suspension concentrate pesticide formulations, with the aim of the product quality control. Azoxystrobin, strobilurin fungicide and difenoconazole (cis,trans-3-chloro-4-[4-methyl-2-(1H-1,2,4-triazol-1-ylmethyl)-1,3-dioxolan-2-yl]phenyl 4-chlorophenyl ether), triazole fungicide, are used for the protection of plants from wide spectrum of fungal diseases. For the analysis LC system an Agilent Technologies 1100 Series was used. Good separation was achieved on a Zorbax SB-C18 column (5 μm, 250 mm x 3 mm internal diameter) using a mobile phase consisting of acetonitrile/ultrapure water (90:10, v/v), at a flow rate of 0.9 ml/minute and UV detection at 218 nm. Column temperature was 25 degrees C, injected volume was 1 μl. Retention times for azoxystrobin and difenoconazole were 2.504 min and 1.963 min, respectively. This method is validated according to the requirements for new methods, which include linearity, precision, accuracy and selectivity. The method demonstrates good linearity with r2 > 0.997. The repeatability of the method, expressed as relative standard deviation (RSD, %), was found to be 1.9% for azoxystrobin and 0.5% for difenoconazole. The precision of the method was also considered to be acceptable as the experimental repeatability relative standard deviation (RSD) was lower than the RSD calculated using the Horwitz equation of 1.7% and 1.4% for azoxystrobin and difenoconazole, respectively. The accuracy of the proposed method was determined from recovery experiments through standard addition procedure. The average recoveries of the three fortification levels were 101.9% for azoxystrobin and 103.2% for difenoconazole with RSDs of 1.1% and 1.2%. The method described in this paper is simple, precise, accurate and selective and represents a new and reliable way of simultaneous determination of azoxystrobin and difenoconazole in formulated products.

Prevalence of hepatitis E virus (HEV) antibodies in Serbian blood donors

INTRODUCTION

Hepatitis E virus (HEV) infection is rarely reported in industrialized countries, but recent studies have revealed quite variable seroprevalence rates among European populations, including blood donors. In Serbia, very limited data about HEV seroprevalence are available. This study aimed to determine the prevalence of anti-HEV IgG antibodies and HEV RNA in the sera of volunteer blood donors in Serbia.

METHODOLOGY

Serum samples from 200 volunteer blood donors were tested for the presence of anti-HEV IgG by enzyme-linked immunosorbent assay (ELISA) using ORF-2 HEV genotype 3 recombinant proteins as antigen, and for the presence of HEV RNA by nested reverse transcriptase polymerase chain reaction (RT-PCR).

RESULTS

In total, 15% of the volunteer blood donors were seropositive. The prevalence increased with age; 21.5%, 14.2%, and 5.4% HEV seroprevalence rates were found in individuals older than 51 years, between 31 and 50 years, and in those younger than 30 years of age, respectively. However, no HEV RNA was detected in any of the individuals analyzed.

CONCLUSIONS

The prevalence of anti-HEV IgG among blood donors as representatives of the general population is quite high in Serbia compared to data from many European countries. One of the reasons for this could be the high prevalence of HEV among Serbian pigs and the traditional consumption of piglet meat in the country. The relatively high HEV seroprevalence found among Serbian blood donors indicates the need for further investigation.

STUDY OF THE EQUINE VIRAL ARTERITIS SEROCONVERSION AT HORSE STABLES IN THE TERRITORY OF VOJVODINA

The paper presents the results of the study on equine viral arteritis presence in five horse stables in the territory of Vojvodina. The research encompassed analysis of clinical manifestation of the disease and seroconversion to equine viral arteritis throughout a two-year period (2012 and 2013). Analysis of clinical manifestations of the disease was performed according to the anamnestic data obtained from staff veterinarians on the stud farms. Prevalence of equine viral arteritis was determined by testing 204 blood serum samples from 102 horses. Sera samples were collected twice at oneyear interval, i.e. in 2012 and 2013, and examined by virus neutralization test. Seropositive results as well as seroconversion were obtained on one of the five investigated horse stables. At the stable with seropositive animals, 27 horses were serologically tested at one-year interval. Out of the total of 27 animals, antibody positive sera were obtained in 16 and 17 horses in 2012 and 2013, respectively. Antibody titre values ranged from 1 to 10 log2, with average values of 3.11 and 3.15 log2 in 2012 and 2013, respectively.

Monitoring West Nile virus (WNV) infection in wild birds in Serbia during 2012: first isolation and characterisation of WNV strains from Serbia

West Nile virus (WNV), a neurovirulent mosquito-transmissible zoonotic virus, has caused recent outbreaks in Europe, including Serbia from August until October 2012. Although humans can be infected, birds are the main natural WNV reservoir. To assess WNV circulation in northern Serbia, 133 wild birds were investigated. These comprised resident and migratory birds, collected between January and September 2012 in the Vojvodina province. The birds belonged to 45 species within 27 families. Blood sera (n=92) and pooled tissues from respective birds (n=81) were tested by enzyme-linked immunosorbent assay (ELISA), plaque reduction neutralisation test (PRNT) and real-time reverse transcription-polymerase chain reaction (RT-qPCR). WNV antibodies were detected in seven (8%) sera: four from Mute Swans (Cygnus olor), two from White-tailed Eagles (Haliaeetus albicillas), and one from a Common Pheasant (Phasianus colchicus). Five sera neutralised WNV but not Usutu virus. For the first time in Serbia, WNV RNA was detected by RT-qPCR in pooled tissue samples of eight respective birds. WNV RNA was also derived from an additional bird, after a serum sample resulted infective in cell culture. The total nine WNV RNA positive birds included three Northern Goshawks (Accipiter gentilis), two White-tailed Eagles, one Legged Gull (Larus michahelis), one Hooded Crow (Corvus cornix), one Bearded Parrot-bill (Panarus biramicus), and one Common Pheasant. Phylogenetic analysis of partial E region sequences showed the presence of, at least, two lineage 2 Serbian clusters closely related to those responsible for recent human and animal outbreaks in Greece, Hungary and Italy. Full genomic sequence from a goshawk isolate corroborated this data. These results confirm WNV circulation in Serbia and highlight the risk of infection for humans and horses, pointing to the need for implementing WNV surveillance programmes.

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.

SEROPREVALENCE OF BOVINE RESPIRATORY SYNCYTIAL VIRUS (BRSV) IN VOJVODINA

This paper presents the results of serological examination of respiratory infection with bovine respiratory syncytial virus (BRSV) on dairy farms and cattle feedlots in Vojvodina. Seropositive animals were detected on all examined farms. The seroprevalence differed depending on the age of examined animals, i.e. of animal production group. For dairy cattle seroprevalence was the lowest in calves aged about 3.5 months, and in animals older than 1 year it was 100%. In the calves between 30 and 70 days of age, when pneumonia was frequent, seroconversion was not detected. Upon the arrival of new calves in feedlots seroprevalence was 22.89%. The number of seropositive animals during the fattening period increased, so after reconvalescence of clinical pneumonia, 90% of animals were seropositive, and 96.43% at the end of fattening period. This investigation detected prevalence of BRSV and its importance in the etiology of pneumonia, especially in feedlots.

Acoustically driven photon antibunching in nanowires

The oscillating piezoelectric field of a surface acoustic wave (SAW) is employed to transport photoexcited carriers, as well as to spatially control exciton recombination in GaAs-based nanowires (NWs) on a subns time scale. The experiments are carried out in core-shell NWs transferred to a SAW delay line on a LiNbO(3) crystal. Carriers generated in the NW by a focused laser spot are acoustically transferred to a second location, leading to the remote emission of subns light pulses synchronized with the SAW phase. The dynamics of the carrier transport, investigated using spatially and time-resolved photoluminescence, is well-reproduced by computer simulations. The high-frequency contactless manipulation of carriers by SAWs opens new perspectives for applications of NWs in opto-electronic devices operating at gigahertz frequencies. The potential of this approach is demonstrated by the realization of a high-frequency source of antibunched photons based on the acoustic transport of electrons and holes in (In,Ga)As NWs.

THE SEROPREVALENCE OF HEPATITIS E VIRUS INFECTION IN WILD BOARS IN SERBIA

Hepatitis E (HEV) belongs to one of fi ve so far described types of viral hepatitis caused by human agents (hepatitis A, B, C, D and E). The disease is characterized by clinical and epidemiological signs of acute hepatitis and is transmitted primarily by fecal-oral route via contaminated food and water. The infection is mainly detected in the developing countries of the Middle East, Asia and Africa, especially in countries with poor sanitary conditions of life. HEV infection in pigs was fi rst recorded in 1990. Numerous studies that followed proved that HEV can skip species barrier and can be transmitted from pigs to humans. HEV has been demonstrated as a new zoonotic agent. Hepatitis E virus has infected people in Japan who consumed insuffi ciently cooked meat of deer, pig liver and meat of wild boar. In humans four genotypes have been determined: I, II, III and IV, while so far tested swine isolates belong to genotypes III and IV. It is also important to note that the swine HEV isolates from one geographical region are genetically closer to human isolates from the same area than to the other isolates from pigs in the world. Th e aim of this paper is to show whether and how much HEV infection is present in the population of wild boars in Serbia, which represent a reservoir of this disease caused by a signifi cant zoonotic agent. Preliminary serological tests included the examination of 92 blood serum samples of wild boars. In 32 animals, or 34.78%, the presence of specifi c antibodies against HEV genotype was detected. Th e blood samples were collected during 2009, 2010 and 2011 from 15 hunting sites in Serbia. Laboratory testing was performed by non-commercial ELISA (in-house ELISA), where the used antigen was recombinant capsid protein-HEV genotype 3 ΔORF 2, which was obtained by laboratory cloning procedure. The test results showed that the hepatitis E virus is present in wild boars in Vojvodina, that are a potential source of this infection, as well as for many other infections of diferrent etiology.

Borrelia burgdorferi in ticks and dogs in the province of Vojvodina, Serbia

Lyme disease is a tick borne zoonotic infection, caused by Borrelia burgdorferi s.l. bacteria. For the transmission of the disease, the presence of ticks is a prerequisite. Lyme borreliosis mostly occurs in people and dogs, but it may occur in other animals. Ticks which carry B. burgdorferi s.l. in Serbia are of the Ixodes ricinus specis. In Serbia, Lyme disease was detected for the first time in the late '80-es. In dogs, clinical symptoms may occur even months after a tick bite, and include weakness, lymphadenopathy, fever, lameness, arthritis, etc. In our survey, we have observed tick and dog populations in the province of Vojvodina (northern part of Serbia). I. ricinus ticks were collected and examined for the presence of B. burgdorferi s.l. in several chosen locations. In addition, blood samples were collected from house dogs and pets from the same locations, and analyzed for the presence of antibodies specific for B. burgdorferi s.l. The results showed a mean infection of ticks of 22.12%, and a mean seroprevalence of Lyme disease in dogs of 25.81%. We conclude that in Vojvodina there is an actual risk of Lyme borreliosis for other animals and humans, because of the persistence of B. burgdorferi s.l. in both tick and dog populations.

MECHANISMS OF INCREASED RESISTANCE OF BACTERIA TO ANTIMICROBIALS IN BIOFILM

The most striking advantage of bacteria residing in biofilm is enhanced resistance to biocide including antibiotics and disinfectants. Biocides are 100% efficient in killing cells in suspension but there are not efficient in destroying bacteria from biofilm community. Mechanisms of increased resistance of bacteria in biofilm to antibiotics is not understood. Some factors alone or in combination are considered to be responsible such as restricted penetration of antibiotics into a biofilm, slow growth rate of biofilm cells, possible expression of certain resistance genes, increased rate of genetic transfer. The standard test for estimating the minimum bactericidal and minimum inhibitory concentration is not applicable for bacteria grown in biofilm. Nowadays, the apparatus for determination of Minimal Biofilm Eradication Concentration (MBEC) has been developed. Determining MBEC helps to select appropriate antibiotics for patient treatment, to identify new antimicrobials targeting biofilm and to track the possible future development of antibiotic resistance against biofilm drugs.

MODERN LABORATORY DIAGNOSTIC METHODS IN VETERINARY MEDICINE AND THE POSSIBILITY OF ITS APPLICATION

One of the greatest challenges of modern laboratory diagnosis is the selection of methods for fast, highly sensitive and specific detection of the infective agents. This challenge is present also in molecular diagnosing of causative agents in veterinary medicine. An example of molecular detection, the application of molecular diagnostic methods and procedures in the epizootiology of some viral infections is presented in the paper. The molecular methods play an important role in virus detection and surveillance. Out of a large number of molecular methods most frequently used are classical gel-based PCR (PCR, RT-PCR and nested PCR) and real-time PCR or RT-PCR techniques. Due to highly specificity and sensitivity these methods have been introduced as internationally recognized methods for virus detection in clinical materials. The advantage of the aforementioned molecular methods is that they are very fast and highly sensitive, and able to analyse a high number of samples. The obtained results may be used in molecular epizootiology, possibly for differentiation of filed isolates and vaccine virus strains, and for examining the samples not suitable for virus isolation. Alongside, these methods provide accurate quantification of viral particles in sample material. The detection with high sensitivity and specificity is of utmost importance in detection and typisation of the agents of highly contagious diseases and zoonoses. An example of rapid detection and sensitivity of RT-PCR and real-time RT-PCR in detection and characterization of avian influenza virus in clinical material as well as BVD virus in native bull semen is presented. Besides, molecular methods may be used for other purposes. Genome fragments amplified by PCR and RT-PCR, may be sequenced and used for classification, i.e. for virus isolate genotypisation. The results obtained in this way may be used for basic molecular research in epizootiology, that will point on the source of infections, their correlation and the prevalence of the causative agents what can help in finding the answer to the question why the diseases have occurred and what are the perspective for diseases outcome in the future. Also, these examination may help in determining pathogenicity, virulence and the spread of the pathogen agents. These information are of immeasurable importance for all the procedures in disease prevention and control. The possibilities of sequencing, molecular typisation and epizootiology of BVD virus and CSF virus isolated in Vojvodina in the last years are given as an example how this method can be used.

LABORATORY DIAGNOSTICS OF CURRENT INFECTIOUS DISEASES ACCORDING TO INTERNATIONAL STANDARDS

One of the greatest challenges of modern laboratory diagnostic is selection of methods and procedures for fast and reliable diagnostic. Contemporary laboratory diagnostic is faced with the request to develop the technologies for rapid detection of agents and identification of biological features, as for example pathogenicity, group affiliation, sensitivity, or even genetic sequencing. Beside the aforementioned requests, laboratory diagnostic must implement numerous international standards and apply the principles of good laboratory practice. By compliance to international standards, i.e. good laboratory practice, laboratory diagnostic has considerably been improved, especially regarding the validity of the obtained results. With the aim to improve laboratory diagnostic of infectious diseases in veterinary medicine, this paper presents the demands of the standard SRPS ISO/IEC 17025:2006 (General Requirements for the Competence of Testing and Calibration Laboratories), SRPS ISO 15189:2008 (Medical Laboratories – Particular Requirements for Quality and Competence) as well as the demands of World Organization for Animal Health (O.I.E). Implementation of these standards is presented through the procedures of laboratory diagnostic of most important bacterial and viral animal infections on the territory of the Republic of Serbia. This paper presents the demands regarding the reference material, equipment, workspace and staff, for the laboratory diagnostic of the following diseases: anthrax, leptospirosis, paratuberculosis, Q fever, chlamydiosis, tuberculosis, mycoplasmosis, brucellosis, listeriosis, pasteureliosis, salmonellosis, clostridiosis, Aujeszky’s disease, blue tongue, rabies, infectious bronchitis in poultry, influenza, atypical poultry plague, infectious bursitis, Mareck’s disease, bovine viral diarrhea, enzootic bovine leukosis, infectious bovine rhinotracheitis, equine infectious anemia, equine rhinopneumonitis, equine viral arteritis, maedi-visna, classical swine fever and porcine reproductive and respiratory syndrome.

SEROLOGICAL EXAMINATION OF PARVOVIRUS INFECTION ON PIG FARMS

Porcine parvovirus (PPV) is one of the causative agents in reproductive disorders in swine that causes great economic losses. The objective of our research was to determine prevalence of this infection on farms with intensive breeding in 5 municipalities in Vojvodina. The research encompassed 19 herds with a total of 344 blood samples screened for the presence of antibodies against PPV (gilts, breeding sows and boars). Serological examination was carried out by haemagglutination inhibition test (HI test). After the analyses of the results, seropositive animals were detected on the farms and there were no PPV-free farms. The determined antibody titre against PPV ranged from 1:64 to 1:16384. Out of 344 examined animals, there were 305 (88.66%) with a high antibody titre (1:1024 to 1:16384). The highest level of antibodies (1:16384) was detected in 145 animals, what is 42.15% of total number. In 24 animals (6.97%) titre antibody was 1:512 and these animals were of low seropositivity. Simultaneously, a comparison of antibodies in blood sera was carried out on 20 gilts (Table 3, farm 2) originating from a farm where the animals were vaccinated against PPV and 20 unvaccinated gilts (Table 4, farm 1) originating from a farm without vaccination against PPV. In unvaccinated animals antibody titre was unequal and ranged from 1:256 to 1:16384, in unvaccinated animals the values were considerably higher and ranged from 1:4096 do 1:16384, and in 17 out of 20 vaccinated pigs (85%) the highest antibody titre was 1:16384.

TESTING THE PREVALENCE OF BVDV INFECTION IN LARGE AND SMALL CATTLE HERDS IN SOUTH BACKA AND SREM DISTRICT

Bovine viral diarrhoea (BVD) is a worldwide viral cattle disease. Percentage of seropositive animals, especially in the countries with intensive cattle breeding ranges from 60-90%. This infection on our epizootiology area, as well as on area in our surrounding, was for the first time described by OEuriåkoviñ et al. (1966) based on clinical pictures and pathomorphological findings. This was proved by antibody detection by Cvetnić et al. (1968). In the last few years a large number of serology examination was done on the presence of BVDV infection in our area. In 2004 an examination on virus neutralisation antibodies in sera of breeding dairy cattle older than 6 months was carried for the purpose of determining the prevalence of BVDV infection in large and small herds in Southern Bačka and Srem districts. There were 7577 sera samples from small herds, out of which 3457 were from Southern Bačka (26.31% out of total population in all 9 municipalities), and there were 4120 samples from Srem district (25.17% out of total population in all 8 municipalities). The examination included the animals from all settlements (156). From large cattle herds there were 3019 sera samples, out of which 2721 were from 18 large farms in Southern Baåka (38.65% out of total population), and 298 from 4 large farms in Srem district (29.22% out of total population). This examination encompassed animals from 22 large farms on this area. Virus neutralisation test (VN) was carried out according to the standard procedure described in ’’Manual of Diagnostic Tests and Vaccines for Terrestrial Animals’’ Office International des Epizooties (2004) with slight modifications. For test NADL strain of BVD virus and MDBK cell culture were used. The sera were examined in double dilution from 1:2 to 1:512. Virus neutralisation antibodies for NADL strain BVDV were detected in 1833 (24.19%) in the samples from small herds. Out of this number there were 1082 (31.30%) seropositive animals from Southern Baåka and 751 (18.53%) from Srem district. The largest number of seropositive animals in Southern Baåka district were detected in Titel municipality (68.07%) and the lowest in Bački Petrovac municipality (6.63%). In Srem district the largest number of seropositive animals was in Beoåin municipality (34.16%) and the lowest in Irig municipality (7.62%). When comparing all the settlements, the percentage of BVDV seropositive animals ranged from 0% (i.e. settlements with no seropositive animals) up to 86.67% (Krnjeãevci). Virus neutralisation antibodies for BVDV NADL strain were detected in 1667 (55.22%) samples from large cattle herds. Out of this number there were 1500 (55.13%) seropositive animals from Southern Bačka, and 167 (56.04%) seropositive animals from Srem district. The prevalence of seropositive animals in large herds from Southern Baåka district ranged from0%(5 large herds) up to 96.61%. High prevalence (70%) was detected in 7 out of 18 examined herds. The prevalence of seropositive animals originating from large herds in Srem district ranged from 0% (1 large herd) to 96.96%. High prevalence (70%) was detected in 2 out of 4 examined herds. Detected variation in the percentage of seropositive animals in some areas and herds most probably is the result of animal origin and management on the farms, i.e. movement of animals with introduction of new animals into a herd, what also means that the virus enters into a herd and outbreaks of BVDV infection occur. The titre ofVNantibodies in a certain number of animals, especially on certain areas and in some herds ranged up to 1:512 and even more, what was a clear indication of current or recent presence of persistently infected animals in these herds. High percentage of seropositive animals (70%) in 9 large herds most probably is the result of uncontrolled animal movement, entering of BVD virus and frequent outbreaks of BVDV infections in these herds, but this also indicates probable presence of persistently infected animals in the herds. The obtained results point on high prevalence of BVD infection in the examined area. This prevalence is not equal, what point on existence of areas where the infection is not present, or is present only sporadically.

PREVALENCE OF HERPESVIRUS 1 IN SMALL HERDS IN SOUTHERN BAČKA AND SREM DISTRICT

Bovine herpesvirus type 1 infection (IBR/IPV virus) presents the most spread infection in nowadays cattle breeding. Bovine herpesvirus-1 (BHV-1) may be an agent of serious health disorders causing great economic losses. Since the largest number of cattle in Southern Baåka and Srem district are raised in small herds (what may considerably influence effective implementation of program for control and eradication of BHV-1 infection) it was necessary to investigate the prevalence of BHV-1 infection in the cattle population in this area, what was the aim of this work. Detection and estimation of the presence and prevalence of BHV-1 was done by detection of specific antibodies against BHV-1 in sera samples of cattle raised individually or in small herds (up to 20 animals) collected during the State Program of Disease Control in 2005 and 2006. The sampling was randomly carried out taking care that the samples from all the settlements and municipalities in Southern Bačka and Srem were present. A total of 16,610 samples was collected. Animals seropositive for BHV-1 were detected in all municipalities, but not in all settlements. The highest percent of seropositive animals was found in Beočin municipality(27.27%), Titel municipality (27.16%), Žabalj (22.45%) and Stara Pazova municipality (22.15%). The lowest prevalence was in Bački Petrovac (8.16%) and Temerin municipalities (9.68%). In other municipalities the prevalence ranged between 10% and 20%. From the obtained results it can be concluded that BHV-1 infection was not present in 10 settlements in Southern Bačka and 14 settlements in Srem district. In other settlements (151) the percentage of seropositive animals ranged from 1 to 50%. However, if we analyze the obtained results in the area, it may be concluded that the prevalence is almost the same: in Srem district there were 18.42% and in Southern Bačka 18.79% seropositive animals. Low prevalence was detected in the majority of settlements. The data that in 24 settlements in both districts there were no seropositive animals His an encouraging information. This points on a possibility of easier and faster implementation of control measures and eradication of BHV-1 infection. The results obtained in serology examination provide us an insight in immunology status of small herds in Southern Bačka and Srem districts, what is a starting point in designing and implementing necessary measures with the aim to prevent cases of this disease, as well as its spreading and eradication.

The prevalence of Shiga toxin-producing Escherichia coli in domestic animals and food in Serbia

Faecal samples of 2660 domestic animals from 116 farms and 956 samples of food were examined for the presence of Shiga toxin-producing Escherichia coli (STEC). STEC was recovered from 126 (15.3%) cattle, 135 (11.3%) pigs, 135 (66.8%) sheep, 31 (73.8%) goats, 4 (1%) chicken, and 15 (1.6%) food samples. Of all STEC isolates, 21.5, 25.8 and 15% produced enterohaemolysin, alpha-haemolysin, and aerobactin respectively, 1.6% displayed localized adherence (LA) to HEp-2 cells, 27.6% were sorbitol negative, and 30% were resistant to antibiotics. Only 14 (3.1%) of the STEC isolates belonged to human infection-associated serogroups (O26, O55, O111, O128 and 0157), designated as enterohaemorrhagic E. coil (EHEC). This study revealed that STEC are prevalent in domestic animals, and to a lesser extent in food of animal origin in Serbia, but the absence of a EHEC phenotypic profile (characteristic serogroup, LA, enterohaemolysin production) in most animal STEC strains may explain the low incidence of human STEC infection in this part of the world.