Prevalence of porcine circovirus 2 infection in pig population in Slovakia.

The prevalence of porcine circovirus 2 (PCV-2) infection in the pig population in Slovakia was investigated. Sera from pigs suspected for post-weaning multisystemic wasting syndrome (PMWS) as well as clinically healthy pigs were tested for viral DNA and specific IgM and IgG antibodies. Pigs (n = 198) were categorized to weaning, grower and fattening ones and sows. The results showed that PCV-2 antibodies were present in 53.4% of PMWS-suspects, in 50.0% of healthy pigs and in 69.0% of sows. In PMWS-suspect grower pigs, 40.7% were positive for IgM+IgG antibodies and 22.2% for viral DNA. In PMWS-suspect fattening pigs, 50.0% were positive for IgM+IgG antibodies and 25.0% for viral DNA. In healthy fattening pigs, almost 90.0% were positive for IgG antibodies and 38.5% for viral DNA. The highest proportion of PMWS-suspects was in grower pigs and specific antibodies were increasing with the age of pigs. A combination of positivities for IgG+IgM antibodies and viral DNA was a highly significant marker of PMWS. Viral DNA was detected in seropositive as well as seronegative PMWS-suspects. Overall, in all categories of pigs tested, specific antibodies and viral DNA were detected in 54.0% and 35.5%, respectively.

The effect of the mode of sampling on BHV-1 detection in infected cattle by dot-blot hybridization.

The BHV-1 genome in nasal swabs and washings was detected by dot-blot hybridization using the 32P-pUR-1 probe (1.8 kb EcoRI-HindIII random fragment of BHV-1 DNA ligated into the pUC-9 plasmid) as early as on day 1 after the experimental infection of cattle. In dependence on the sampling method, differences were observed in the maximum of hybridization signals. During nasal swab analyses maximum amounts of BHV-1 differed in the individual samples (day 1-3). Hybridization signals obtained at the analysis of BHV-1 DNA nasal washings did not vary but showed a continuous maximum on day 2 after infection. Nasal washings proved to be more advantageous for detection of the BHV-1 genome by the hybridization technique.

[Detection of bovine herpesvirus-1 using the dot-blot hybridization method]. / Detekcia bovinného herpesvírusu-1 metódou dot-blot hybridizácie.

With the development of molecular biology in the 1980s methods of microorganism detection start to innovate. One of the main advantages of the molecular-genetic methods, namely hybridization of nucleic acids and PCR methods, is the detection of genome of microorganism without the need for cellular cultivation. To detect BHV-1 (etiological agens IBR-IPV) the dot-blot hybridization method on nitrocellulose filters was used together with different types of DNA probes (two-fiber recombinant plasmids, one-fiber recombinant phages M 13 and 40 bp synthetic oligonucleotide). Genome DNA BHV-1 was isolated from samples (virions, infested cells, nasal smears and secretions by phenol extraction). The highest sensitivity of detection was achieved with 32P-pUR-1 probe (1.8kb random EcoRI-Hind III fragment ligated into plasmid pUC 9) which detected genome BHV-1 in 5 x 10(3) infested MDBK cells. This probe did not respond with herpetic viruses BHV-2, BHV-3, BHV-4 and the virus of Aujeszky's disease. The quality of pUR-1 probe was further tested for IBR diagnostics in animals experimentally infested with the virus BHV-1 (intranasal infection). BHV-1 could be detected in nasal smears and secretions in experimentally infested calves as early as on the first day following infection, while the agens amount reached its peak on the days 2-3 and on the days 6-7 the occurrence of virus fell markedly. When digoxigenin-pUR-1, i.e. non-radioactively marked probe, the virus presence was confirmed only on the days 2-3, in the time of the highest occurrence of infection agens. To detect the virus through the dot-blot hybridization nasal secretions were confirmed as better compared with nasal smears. The technology of virus isolation on cell cultures confirmed also the occurrence of agens as soon as on the first day from infection, with maximum on the days 2-5, but much more reliably it detected the virus on the days observed from the day 3 and their peak was obtained on the day 6 from infection. Experiments, comparing classical methods of IBR diagnostics (detection of specific antibodies, the method of isolation on cellular cultures) with the dot-blot hybridization using the samples obtained from farms with natural occurrence of IBM, are under progress.

[The effect of primary BHV-1 infection on the dynamics of T and B lymphocytes in the peripheral blood and levels of specific serum antibodies in calves treated with glucan]. / Efekt primárnej BHV-1 infekcie na dynamiku T a B lymfocytov periférnej krvi a hladinu specifických sérových protilátok u teliat osetrených glukánom.

In the present study we investigated the dynamics of circulating T and B lymphocytes and serum specific antibodies in calves experimentally infected with IBR virus (I group) and in calves administered glucan (seven days before infection) and the infected (GI group). The percentages of T and B lymphocytes in the peripheral blood were determined from analyses by rosette methods; the titer of serum anti-IBR antibodies was determined by virus-neutralizing test on cell cultures. The dynamics of the percentage of circulating T lymphocytes showed a similar decreasing trend in both groups, with significant values on days 3 to 5 after infection (AI). In comparison with the calves of I group, the outset of T cell reduction was found to be less pronounced (within the first two days after infection), with a statistically significant difference on day 2 AI (P < 0.05), Fig. 1. A decrease in the percentage of T lymphocytes was related to an increase in the percentage of circulating B lymphocytes, with maximum on days 3 and 4 AI (P < 0.05), Fig. 1. All the calves before experiment beginning were free of serum anti-BHV 1 antibodies. They started responding to the experimental infection with IBR virus by production of serum antibodies between week 1 and 2 AI. The dynamics of serum anti-IBR antibodies showed an identical course in both experimental groups, with the more pronounced outset (P > 0.05) of immunological response in the calves of GI group (Fig. 2).(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of bovine herpesvirus 1 with various types of DNA probes.

The method of dot-blot hybridization on nitrocellulose filters by various types of DNA probes (ds recombinant plasmids, ss recombinant M13 phages and a 42bp synthetic oligonucleotide) was used for BHV-1 detection. The highest sensitivity was achieved with the 32P-pUR1 probe (1.8 kb random EcoRI-HindIII fragment inserted into pUC9) which detected the BHV-1 genome in 5 x 10(3) infected MDBK cells. Using the pUR1 probe, no cross hybridization was observed with other herpesviruses: BHV-2, 3, 4, and Aujeszky's disease virus. The 32P-pUR1 probe detected BHV-1 in nasal swabs of calves as early as on day 1 after experimental infection. The maximum intensity of BHV-1 detection occurred on day 1-3. The 32P-pUR1 probe also detected BHV-1 in field samples of nasal swabs from cows and calves.

[The effect of an insoluble fungal glucan on indicators of immunity in calves]. / Vplyv nerozpustného fungálneho glukánu na niektoré ukazovatele imunity teliat.

Immunomodulative effect of insoluble fungous glucan (IFG) was observed on nine accidentally chosen calves, which were in the age from 4.5-5.5 months. The following items were observed: T, B lymphocytes, white blood cell count, index and activity of phagocytosis, induction and determination of interferon from leukocytes. In the experimental group there was a decrease in B-rosseting cells observed. On the 28-th day and on the 42-th day of experiment duration a significant increase in B-rosseting cells in comparison with control group has been observed. Average values were significantly different on the levels P < 0.01 and P < 0.05. Percentages of T-rosseting cells were almost the same during the whole experiment. In the experimental group on the 7-th and on the 14-th day the decrease has been observed. By the Student's t-test a significant difference in favour of group, where IFG was applicated, has been observed. Percentage of white blood cell count was from 47 to 72 in both groups. When phagocytic activity was evaluated, there was the higher percentage of phagocytic cells in the 7th, 14-th, 21-st, 28-th and 42-th day of experiment when compared with the 0-day value. Concerning the phagocyte index a statistical difference was observed, when compared to the initial value in favour of the experimental group. The initial disbalanced values of interferon, which have been observed during the period from the 7-th to the 21-st day, increased on the 28-th and the 42-nd day of experiment which was statistically confirmed on the following levels: P < 0.05 and P < 0.01.

[The effect of Zindep inj. preparation on levels of zinc, T-lymphocytes and beta-lysine in the blood of pregnant dairy cows]. / Vplyv prípravku Zindep inj. na zinkémiu, T-lymfocyty a beta-lyzín u gravidných dojníc.

The effects of zinc administration at a rate of 3 mg/kg lw. in the preparation Zindep inj. ad usum vet. (Biotika, Slovenská L'upca) were evaluated as exerted on zinc concentrations in the blood serum of 16 dairy cows in the middle of the 7th month of pregnancy. With respect to zinc injection, T-rosetted lymphocytes and beta-lysine activity were inestigated. Blood was collected from all dairy cows from v. jugularis before the preparation was administered, on days 2, 5, 8, 15, 30 and 60 after Zindep administration. Atom absorption spectrophotometry, applying a flame technique on a Perkin Elmer 1100 apparatus (Bíres, 1986), was used to determine Zn concentrations in the blood serum of all dairy cows. T-lymphocytes were determined by a rosette test after Paul et al. (1977), and beta-lysine was detected spectrophotometrically after Bucharin et al. (1987). Zinc dynamics in the blood serum of dairy cows is presented in Fig. 1. The starting values of zinc in the test cows were 9.68 +/- 2.30 mumol/l and in the control ones 10.15 +/- 1.27 mumol/l. Zincaemia of experimental dairy cows was significantly lower (P less than 0.01) on day 2 after Zindep administration, in comparison with the control group. A significant increase in zinc concentrations in the blood serum of experimental animals, in comparison with the control ones, was observed from day 8 to day 60 (P less than 0.01). The maximum zincaemia values were recorded in experimental dairy cows within days 15 and 30 (15.65 +/- 3.33, and/or 14.55 +/- 2.10 mumol/l).(ABSTRACT TRUNCATED AT 250 WORDS)