Monitoring of Yersinia enterocolitica strains from free-living animals using different methods.

The aim of the study was to monitor Y. enterocolitica strains from free-living animals captured during 2011-2014 hunting seasons in Poland using warm (ITC) and cold (PSB) enrichment and molecular examination. Over 1600 samples have been cultured. After ITC/PSB enrichment 237 strains presenting features characteristic for Y. enterocolitica were isolated. Molecular examination using multiplex PCR revealed 140 isolates from PSB and 78 from ITC. The concentration of pathogenic Yersinia in asymptomatic carriers is low and the PCR detection should be preceded by bacteriological examination.

The influence of experimental Yersinia enterocolitica infection on the pregnancy course in sows--preliminary studies. III. Histopathological lesions.

The aim of the study was to evaluate the anatomo- and histopathological lesions in internal organs of sows and their stillborn piglets after experimental Y. enterocolitica infection in different phases of pregnancy. Twelve pregnant sows were divided into 4 groups, infected per os on 33 (n = 3), 54 (n = 3) and 89 (n = 3) day of pregnancy with the pathogenic Y. enterocolitica strain isolated from the aborted swine fetus, and uninfected control group. Histopathological examinations of internal organs and intestine samples of stillborn piglets, slaughtered sows and samples of placentas were performed. Anatomo- and histopathological lesions were the most intense in the group of sows infected in the final phase of pregnancy, where the highest number of stillborn piglets was also found. Lesions of internal organs in stillborn piglets suggested a severe generalized bacterial infection. Although the analysis of experimental Y. enterocolitica infection of pregnant sows revealed that the most intense clinical, anatomopathological and histopathological abnormalities were recorded in the group of animals infected in the final phase of pregnancy. Infection in the first phase of pregnancy could have had an influence on the formation of the granulomatous inflammation. Differences in anatomopathological lesions between infected and control animals suggest that the period of pregnancy in which the infection appears could have had an influence on the course of yersiniosis in pigs.

Indices of non-specific and specific humoral immunity in pigs immunomodulated with the Bioimmuno preparation and/or immunised with the Respisure One vaccine against mycoplasmal pneumonia of swine.

The purpose of the study was to determine the influence of the Bioimmuno preparation administered in feed and/or immunisation with the Respisure One vaccine on the development of selected indices of non-specific and specific humoral immune response against Mycoplasma hyopneumoniae (Mhp) infections in pigs. The study was performed on 28 piglets at the age of 4 weeks, divided into four equal groups. The biopreparations were administered according to the following pattern: group I--Bioimmuno (IFI Olsztyn, Poland) with feedstuff at amount of 1 kg/50 kg of feed for 48 h before vaccination with Respisure One (Pfizer) on day 28 of life; group II--Bioimmuno only (1 kg/50 kg feedstuff) for 48 h before vaccination with Respisure One of groups I and III; group III--Respisure One only on day 28 of life (2 ml/animal i.m.) and group C (control)--PBS (2 ml/animal i.m.) simultaneously with vaccination of groups I and III. On days 0, 3, 7, 14 and 21 after immunomodulation and/or immunisation, the serum level of gamma-globulins, the activity of lysozyme (LSM) as well as the serum levels of cytokines: interferon gamma (IFNgamma), interleukin 1 beta (IL-1beta) and interleukin 6 (IL-6) were determined, as indices of non-specific immune response against Mhp infections in pigs. The study has revealed that in piglets after weaning the application of the Bioimmuno and/or Respisure One biopreparations improves the non-specific immunity parameters stimulating an increase in serum levels of gamma-globulins, lysozyme and cytokines (IFNgamma, IL-1beta, IL-6), while late appearing seroconversion confirms a minor role of specific humoral immunity in the protection against Mhp infection.

Effectiveness of coupled administration of Bioimmuno immunomodulator and Respisure One vaccine in the prophylaxis of mycoplasmal pneumonia of swine.

The study was aimed at determining the protective value of the coupled application of immunomodulation and vaccination in the prophylaxis of mycoplasmal pneumonia of swine (MPS). It was conducted on a pig farm, on 28 piglets with body weights of 7-8 kg in the peri-weaning period, divided into four groups of 7 animals each. In the experiment, the following were used: Bioimmuno preparation (Institute of Inland Fisheries, Olsztyn) elaborated based on methisoprinol and Saccharomyces cerevisiae, to be administered with feed, as well as an inactivated vaccine against MPS - Respisure One (Pfizer). The first two groups of piglets were administered Bioimmuno with a feed mixture at a dose of 1 kg/50 kg feed for 48 hours prior to the immunization of one of the groups with Respisure One on day 28 of life. The third group of piglets was only vaccinated, whereas the fourth group served as control. Clinical observations were conducted that covered the monitoring of side reactions (local and constitutional), an evaluation of the incidence and character of symptoms manifested by the respiratory system and other health status disorders as well as the determination of the number and percentage of medical interventions and death cases of animals. Animal husbandry examinations and post-slaughter analyses involved the determination of the mean body weight at slaughter, mean daily body weight gains, mean daily feed utilization, and mean feed conversion ratio per 1 kg b.w. gain and an index of quantitative lesions in the lungs. The study did not demonstrate any local side reactions at an injection site of the Respisure One vaccine nor any constitutional side reactions linked with the administration of either preparation. In turn, the clinical and animal husbandry examinations showed a positive effect of administering the Bioimmuno immunomodulator on the effectiveness of immunization against MPS with the Respisure One vaccine and on the improvement of the health status of pigs, which was manifested by a reduced incidence of infections in the piglets with respiratory symptoms, increased b.w. gains, improved feed utilization and shortened fattening period. Due to the diminished intensification of respiratory symptoms and pathological lesions in lungs and the improved fattening indices, the coupled administration of the Bioimmuno and Respisure One biopreparations to piglets may constitute an important element of MPS prophylaxis in pig herds.

The influence of experimental Yersinia enterocolitica infection on the pregnancy course in sows--preliminary studies. I. Bacteriological examination.

The aim of the study was to determine the influence of Yersinia enterocolitica (Y. enterocolitica) experimental infection on the carrying and shedding states of the microorganism by pregnant sows and on the bacteria occurrence in tissues of the infected animals and aborted or stillborn piglets. Twelve pregnant sows were divided into 4 groups and infected per os on 33--group I (n = 3), 54--group II (n = 3) and 89--group III (n = 3) day of pregnancy with the Y. enterocolitica strain isolated from the palatine tonsil of aborted swine fetus. The control group (n = 3) remained uninfected. Rectal, oral and vaginal swabs from sows, placentas and the specimens of tissues from stillborn piglets were collected for bacteriological examination. Eight weeks after delivery, the sows were slaughtered and samples of internal organs were subjected to bacteriological examination. Pregnancy in all groups of sows took a normal course, and no cases of abortion were observed. Y. enterocolitica was isolated from oral, rectal and vaginal swabs of all infected sows. The number of stillborn piglets in the litters was highest in group III, where two macerated fetuses with putrefactive lesions were found. The bacteria were isolated from tissues of stillborn piglets in groups I and III, and only from placenta in group II. In rectal swabs of piglets in all groups, Y. enterocolitica was not isolated. The results of experimental infection of pregnant sows with Y. enterocolitica revealed that in animals infected in the last part of pregnancy, the microorganisms were isolated most frequently from vaginal, rectal and oral swabs of sows as well as from internal organ tissues of stillborn piglets.

The influence of experimental Yersinia enterocolitica infection on the pregnancy course in sows--preliminary studies. II. Antibodies, C-reactive proteins and haptoglobin as an immunological response.

The aim of the study was to determine the time of emergence and level of Y. enterocolitica antibodies in pregnant sows challenged orally with Y. enterocolitica in particular trimesters of pregnancy (groups I, II and III, respectively) and also the assignation of its influence on the CRP and Hp concentration in sera of pigs. Levels of antibodies measured by tube agglutination test increased slowly from 2 weeks post infection (wpi) and positive results were obtained not in all animals. In ELISA, in 2 weeks in all groups of infected animals high levels of antibodies against Y. enterocolitica were formed and lasted up to the end of the experiment. In newborn piglets in all groups, a significant decrease in antibody levels 6 weeks after birth was observed in both agglutination and ELISA tests. Concentrations of CRP as Hp in all groups of infected animals increased in 1 week post infection. Statistically significant differences (P < or = 0.05) between CRP levels in groups I and II (46-fold and 44-fold) as well as III (29-fold) were revealed. In case of Hp, statistically significant differences between groups of animals in the first week post infection were not observed. Our findings indicate that Y. enterocolitica infection evoked strong and long-lasting immunological reaction in the form of specific antibodies production in all inoculated animals. The significant increase in CRP and moderate increase in Hp concentrations in the sera of pregnant sows also occurred. However, relationships between colostrums antibody levels in piglets' sera and phase of pregnancy when the Y. enterocolitica infection happened in sows were not observed.

Analysis of the presence of ail, ystA and ystB genes in Yersinia enterocolitica strains isolated from aborting sows and aborted fetuses.

Forty-five Yersinia enterocolitica strains isolated from aborted fetuses and placentas and from vaginal and rectal swabs of aborting sows were subjected to serotyping, biochemical typing and polymerase chain reaction multiplex analyses to detect the presence of the ail, yst A and ystB genes. The isolates were recovered from the internal organs (tonsil, lung, liver, spleen, kidney, mesentheric lymph nodes, small intestine and rectal intestine) of 18 (18.6%) of 97 aborted fetuses examined, two (8%) of 25 aborted placentas and 27 (15.8%) of 172 examined aborting sows. Serotyping of Y. enterocolitica revealed that only six (13.3%) of the examined isolates belonged to serotype O:3, with a considerable number of isolates (31.1%) having serotype O:5, while biochemical studies showed that as many as 40 of the 45 strains belonged to biotype 1A. As expected, the Y. enterocolitica strains of bioserotype 4/O:3 contained ail and ystA genes, while strains of biotype 1A contained only the ystB gene.

Evaluation of specific humoral immune response in pigs vaccinated intradermally with deleted Aujeszky's disease vaccine and challenged with virulent strain of Herpesvirus suis type 1.

A comparison of intradermal (ID) versus intramuscular (IM) routes of pig vaccination with deleted Aujeszky's disease (AD) vaccine on the formation of specific postvaccinal and postchallenge humoral immune response was performed. The studies were carried out on 21 eight week-old piglets, divided into three groups--two experimental and one control of 7 piglets each. Animals of first two groups were vaccinated twice in 12 and 16 week of age with deleted, live attenuated AD vaccine Porcilis Begonia (Intervet). Group I was vaccinated with a dose of 2.0 ml (10(6.0) TCID50)) intramuscularly (IM) into neck muscles, and group II received 0.2 ml (10(5.0) TCID50) intradermally (ID) in neck area using needleless apparatus SERENA model SD 1-2 (Emplast, Italy). In group K (control) 2.0 ml PBS IM was used. Seventy days after the first vaccination all pigs were intranasally infected with a dose of 10(5.5) TCID50 of virulent Northern Ireland Aujeszky-3 (NIA-3) strain of Herpesvirus suis type 1 (SHV-1) by instilling 0.5 ml of virus suspension into each nostril. Specific humoral immune response was evaluated using seroneutralization (SN) test and gE-ELISA-Pseudorabies virus gpI Antibody Test Kit (Herd Chek Anti-PRV gpI), IDEXX Lab Inc (USA). It was found that challenge caused anamnestic reaction in both groups of vaccinated pigs, but postchallenge immune response was stronger in ID-vaccinated group--on 14 day post infection (dpi) SN antibody level was considerably higher than in IM-vaccinated group. The obtained results suggest that secondary immunological response after challenge is decidedly more effective in the range of evaluated parameters in animals vaccinated by ID route, which can be linked to, perhaps underestimated yet and seldom utilized, skin immunity mechanisms in specific prophylaxis of infectious diseases. Advantages and disadvantages of SN test and ELISA are also discussed.