Jovan Bojkovski

Detection rates of the swine torque teno viruses (TTVs), porcine circovirus type 2 (PCV2) and hepatitis E virus (HEV) in the livers of pigs with hepatitis

Porcine circovirus type 2 (PCV2) and hepatitis E virus (HEV) are the most recently recognized causes of infectious hepatitis of pigs and may or may not act independently in the development of the disease. Recently it has been suggested that swine torque teno viruses (TTVs), in co-infections with some swine viral pathogens, may potentiate the severity of disease. In order to search for virological cofactors associated with infectious hepatitis in pigs, we investigated the liver tissues, to determine the presence of TTVs, PCV2 and HEV of naturally infected pigs and analysed the prevalence of both genogroups of the TTVs in the hepatitis lesions. Histopathological techniques, nested-polymerase chain reactions (nPCRs), polymerase chain reaction (PCR) and one-step reverse transcriptase polymerase chain reaction (RT-PCR) were applied to detect hepatitis lesions, TTVs genogroups 1 and 2, PCV2 and HEV infection. Of the livers examined 58% (29/50) had mild to moderate hepatitis and 74% (37/50), 56% (28/50) and 26% (13/50) samples were nPCR, PCR and RT-PCR positive for TTVs PCV2 and HEV respectively. TTVs were detected in 84% (16/19) of the samples which were determined to be of mild severity while present in almost all (90% or 9/10) samples identified as having moderate hepatitis lesions. Additionally, the livers of 12 out of 21 (57%) pigs without the hepatitis lesions were positive for TTVs. These results demonstrate an association between TTVs and infectious hepatitis of pigs in concomitant infections with PCV2 and/or HEV and indicated that TTVs may play a role as a cofactor in the pathogenesis of disease.

Genetic characterization and phylogenetic analysis of porcine circovirus type 2 (PCV2) in Serbia

Porcine circovirus type 2 (PCV2) is the main causative agent of postweaning multisystemic wasting syndrome (PMWS). To characterize and determine the genetic diversity of PCV2 in the porcine population of Serbia, nucleotide and deduced amino acid sequences of the open reading frame 2 (ORF2) of PCV2 collected from the tissues of pigs that either had died as a result of PMWS or did not exhibit disease symptoms were analyzed. Sequencing and phylogenetic analysis showed considerable diversity among PCV2 ORF2 sequences and the existence of two main PCV2 genotypes, PCV2b and PCV2a, with at least three clusters, 1A/B, 1C and 2D. In order to provide further proof that the 1C strain is circulating in the porcine population, the whole viral genome of one PCV2 isolate was sequenced. Genotyping and phylogenetic analysis using the entire viral genome sequences confirmed that there was a PMWS-associated 1C strain emerging in Serbia. Our analysis also showed that PCV2b is dominant in the porcine population, and that it is exclusively associated with PMWS occurrences in the country. These data constitute a useful basis for further epidemiological studies regarding the heterogeneity of PCV2 strains on the European continent.

THE POSSIBILITY OF DAIRY FARMS ISOLATION ASSESSMENT - BIOSECURITY ASPECT

The effects of general and special biosecurity measures to prevent introduction of infectious agents in a dairy farm or its spreading from farm were analysed in details in this paper. Investigations were conducted on five different dairy farm production with different technology and capacity using a questionnaire method (Hristov and Stankovic, 2009), as well as scrutinizing their positions in relation to possible sources bio-risks from the near and far away environment. Test results showed that there are serious shortcomings on all observed farms, regarding the possibility of introduction of infectious agents in the production herd, and its possible spread to the environment. Although all fenced and a position of the most of the farms mostly favourable, there are some serious threats to the herd health and farm production, regarding open space and lack of green belt, the uncontrolled presence of wild birds and rodents in facilities and even in feed storage, as well as contact of the employees with other cows not belonging to the farm.

Analysis of applied biosecurity measures in boars sperm production.

This paper gives a detailed analysis of the applied biosecurity measures in the production of boar sperm at a swine reproduction center. Biosecurity indicators (existence of a written biosecurity plan, isolation, introduction of newly acquired animals into the herd, herd health, assessment of the personnel attitude towards equipment, traffic control, attitude towards visitors, feeding and watering control, manure management, disposal of dead animal carcasses, attitude towards other animals, rodents and birds control, sanitation) were viewed and evaluated by rating scale: (5) - excellent, (4) - very good, (3) - good, (2) - sufficient, (1) - insufficient, there are resources for improvement (0) - insufficient, with no resources for improvement. Obtained data were analyzed in the SWOT process, taking into account all the strengths, weaknesses, threats and opportunities for improving the biosecurity level. The situation in the center is rated as very good, with an average rating of 4.15. However, one disadvantage is serious and related to the boar facilities isolation possibilities, taking into account their location and the presence of two types of male breeding animals (boars and bulls) in the same location. Newly acquired breeding animals are purchased from various sources, but with a rigorous regime of control and not at the same time.

Tick infestation and occurrence of Anaplasma phagocytophilum and piroplasms in cattle in the Republic of Serbia

Ticks transmit important pathogens affecting cattle such as intracellular bacteria of the genus Anaplasma or protozoa of the order Piroplasmida. This study aimed at assessing tick species present on pastures and cattle and determining occurrence of the tick-borne pathogens Anaplasma phagocytophilum and Babesia spp. in cattle. During May and June 2013, ticks and EDTA blood were collected from 185 dairy cows at six locations in Serbia. Ticks were also collected directly from the pastures at four of these locations. The occurrence of A. phagocytophilum was investigated by serological (immunofluorescence antibody test (IFAT)) and molecular methods (real-time PCR) and of piroplasms by traditional PCR followed by sequencing. The most prevalent tick species on animals was Ixodes ricinus, (n = 167), followed by Haemaphysalis punctata (n = 146) and Dermacentor marginatus (n = 122). On the pasture, however, the most common species was H. punctata (n = 41), I. ricinus (n = 37), and D. marginatus (n = 2). Altogether, 4 out of 163 (2.45%) serum samples of cows were positive for A. phagocytophilum-specific antibodies by IFAT. However, the 135 blood samples tested for A. phagocytophilum DNA were all negative. Altogether, 5 out of these 135 samples were positive for piroplasm DNA. PCR products were sequenced and identified as a benign Theileria spp. with 100% identity with GenBank entries from Italy (Theileria sergenti), China (Theileria spp.), and Korea (Theileria buffeli isolate HS252). The results provide evidence for the presence of several hard tick species infesting cattle in Serbia which can carry pathogens potentially influencing animal health, as well as evidence of contact with tick-borne pathogens Theileria spp. and A. phagocytophilum.

Field Trial on Glucose-Induced Insulin Response in High-Yielding Dairy Cows under Different Environmental Temperatures

Abstract This study aimed to evaluate glucose-induced insulin response in cows exposed to different temperature-humidity index. Twenty early lactating Holstein-Friesian cows were divided into 2 equal groups based on season, as summer (SU) and spring (SP). SP cows were not exposed to heat stress, while SU cows were exposed to moderate or severe heat stress. Milk production was recorded daily. Starting from day 30 of lactation, intravenous glucose tolerance test (IVGTT) was carried out three times at 30-day intervals. Blood samples were taken before (basal) and after glucose infusion, and glucose and insulin were measured at each sample point. The homeostatic model assessment (HOMA) index was calculated. Milk yield from days 30 to 40 and 64 to 90 of lactation were higher in SP cows than in SU cows. Basal glucose did not differ on days 30 and 60 of lactation, while basal insulin and HOMA were lower in SU compared to SP cows. On day 90 of lactation, SU cows had higher basal glucose, whereas basal insulin and HOMA did not differ. IVGTT results revealed that glucose tolerance was affected by heat stress such that SU cows had higher glucose clearance. Insulin responses to IVGTT did not differ on days 30 and 60 of lactation. Heat stress had a marked effect on insulin secretion on day 90 of lactation, illustrated by higher increments, peak concentrations and area under the curve for insulin in SU cows. Overall, season differences in glucose tolerance depend not only on heat stress and milk production but also on the stage of lactation.

Sustainibility ahd Efficiency of Dairy Farms Biosecurity Plans

Basic principles of biosecurity plans creation and inplementation were given in this review paper. This include goals wanted to be acheived related to specificities of dairy farm technology, sellection of measures that have to be included, order and manner of measures description, inplementation, as well as failures in plan execution. Efficiacy and further sustainibility of biosecurity plans inplementation could be measured through differences between biosecurity level before and after plans application established by questionnaire about biosecurity indicators, such as: 1. isolation of the farm and its organization, 2. quarantine and newly purchased cows policy, 3. visitors policy, 4. attitude towards equipment use, 5. pest control, 6. sanitation efficasy and 7. farm impact on environment. The stakeholders have to define and develop plan to keep potential pathogens for dairy herd health and production in cooperation with the veterinarian and the other professionals advising on organisation and production technology. At least once a year, it is necessary to reconsider the plan and supplemented by new practical experience and scientific knowledge.

The application of PCR based methods in diagnostics of some viral infections of swine

Viral infections of swine cause significant economic losses in swine husbandry. They manifest in death of infected animals of different ages or in decreased productivity during the manufacturing process. Having that in mind, rapid and reliable diagnostics of viral infections is crucial in the prevention of disease transmission in herds of swine. Today, virological laboratories all over the world use different diagnostic methods such as isolation of virus in cell lines, ELISA, virus neutralization test, direct and indirect immunofluorescence and hemagglutination and hemagglutination inhibition tests. Virus isolation, virus neutralization test and some other standard virological methods are time consuming and rather expensive, therefore, molecular methods such as conventional PCR, RT PCR, real-time PCR and direct sequencing methods are applied worldwide as fast and reliable. Their application is especially necessary for the detection of viruses which cannot be identified by using standard virological methods.

Antimicrobial Resistance in Isolates From Sow Nares From Comercial Farms in Methicilllin Resistant Staphylococci (Mrs) And Expended Spectrum Beta Lactamate Antibiotics (Esbl) in Enterobacteriacea Models

Spreading of antimicrobial resistance is a great problem in human and animal medicine. Rising in occurrence in methicillinresistant Staphylococcus spp. (MRS) as well as expended spectrum beta lactamate antibiotics resistance (ESBL) in animals may be potential danger for farm workers in disease spread. Nasal and rectal swabs were taken from 53 sows without clinical symptoms on two farms in Serbia. Nasal swabs were tested on MRS and rectal on ESBL. Laboratory test showed 1 ESBL isolate (1.9%) and 18 (35.85%) MRS of which 3 (15.8%) Staphylococcus aureus and 7 (36.85%) Staphylococcus epidermidis. Seven of nineteen random MRS isolates were put on disc diffusion method. None of them showed resistance to vankomycine (VRSA) and fusidic acid.

EVALUATION OF CONTROL SCHEMES USING PROTEIN SUPPLEMENTATION AND ANTIHELMINITICS AGAINST GASTROINTESTINAL NEMATODES OF DAIRY EWES

The purpose of the study was to investigate the possible influence of dietary protein supplementation and anthelmintic administration, in different schemes, for the control of gastrointestinal (GI) nematodes of dairy ewes under field conditions. Towards this end, 40 clinically healthy ewes of a local Greek dairy breed, grazing on infected irrigated pasture, were divided into 5 groups and treated as follows: Group (1S) supplemented with 300 g soybean meal 48%, twice per year (July and periparturiently), Group (2Alb) received albendazole twice as (Group 1S), Group (3S-Alb) supplemented with soybean as in (Group 1S) combined with the use of albendazole (as in Group 2Alb), Group (4Alb3) received albendazole three times (September, periparturiently and April) and Group (5C) (control group). Faecal samples were taken from each animal monthly for nematode egg count (FEC) and blood samples every two months for haematological and biochemical analysis. The results showed that the administration of albendazole twice reduced effectively the nematode FEC, whereas the extra protein supplementation did not significantly influence it. Haematocrit and total proteins were unaffected although they tended to be lower in the control Group (5C). Pepsinogen, calcium, inorganic phosphorus and magnesium were not influenced by the treatments.