The aim of the study was to analyse the prevalence of single-reactor (SR) pigs in Poland, to attempt an explanation for this phenomenon, and to assess whether the occurrence of SR pigs could create problems for a successful Aujeszky’s disease virus (ADV) eradication programme in Poland. A total of 6494 ADV gE antibody positive/doubtful sera were retested by gB ELISA and subsequently by virus neutralisation test (VNT) to confirm the results of the glycoprotein E (gE) ELISA. Amongst the serum samples tested, 5.9% could be classified as being taken from SR pigs, as was shown by gE ELISA positive/doubtful results, which were not confirmed by negative findings in gB ELISA and VNT. It means that the observed SR phenomenon was due to a false positive/doubtful reaction in gE ELISA. This finding was strongly supported by the fact that the serum samples were taken from the animals from herds without any previous or subsequent history of Aujeszky’s disease. The low percentage of SR pigs does not seem to create a big obstacle to a successful ADV eradication programme in Poland.
Twenty pigs of similar genetics (PIC) were used. Pigs were randomly divided into two groups: experimental (ENRO, n = 10) and control (C, n = 10). From day 0 to day 4, pigs from ENRO group received enrofloxacin at the recommended therapeutic dose. Pigs from C group received PBS instead of enrofloxacin. Blood samples were collected on days 0 (before antibiotic administration), 2, 4 (during antibiotic therapy), 9, and 13 of the study (after enrofloxacin administration). Haematological examination and flow cytometry were used to establish the relative and absolute counts of various leukocyte subsets. Lymphocyte subpopulations were measured by fluorochrom-labelled antibodies according to following definitions: CD3+ (T cells), CD21+ (B cells), CD4+CD8- (helper T cells, Th), CD4-CD8+ (cytolytic T cells, CLT), CD4+CD8+ (cytolytic and memory T cells). The present study revealed the modulating effect of enrofloxacin on the composition of circulating lymphocytes in pigs. Concentration and percentage of CD8+ cells decreased significantly after treatment with enrofloxacin and as a result the absolute CD4/CD8 ratio increased significantly as compared to control group (P < 0.05).These findings should prompt further studies on the practical significance of the results obtained in terms of clinical implications. In view of the results, it cannot be excluded that enrofloxacin may also have immunomodulatory effects on host response to infection.
Grzegorz Woźniakowski, Magdalena Frączyk, Krzysztof Niemczuk and Zygmunt Pejsak
African swine fever (ASF) is currently one of the most severe viral infections of domestic pigs, wild boars, and other hosts belonging to Suidae family. ASF is also considered as the most complex and devastating infectious and haemorrhagic disease of swine due to its severe socio-economic impact and transboundary character. ASF it is a notifiable disease and due to the lack of specific treatment and vaccine, the disease can be only limited by the administrative measures comprising wild boar hunting and stamping out of affected pigs. ASF occurred for the first time in Kenya in 1921 while in Europe (Portugal) the virus was detected at the end of the 1950s. In spite of successful eradication of this threat in a number of affected regions, the virus remains endemic in both feral and domestic pigs in Africa and Sardinia. The ‘new era’ of ASF started in 2007 after its re-introduction to Georgia. Following its intensive expansion, the virus spread to other Caucasian countries, including the territory of the Russian Federation. In 2014 the virus reached Ukraine, Belarus, and, consequently, European Union countries: Lithuania, Latvia, Estonia, and Poland. The occurrence of ASF in wild boars and pigs had a severe impact on both epidemiology and economy because of the national and international transport and trade consequences. Up to date, starting from the February 2014, eighty ASF cases in wild boar and three outbreaks in domestic pigs have been diagnosed. Taking into account the diverse rate of spread in Poland, this review aims to present and discuss the current state of knowledge on ASF including its epidemiology, pathology, transmission, and perspectives of control.
Anna Szczotka-Bochniarz, Katarzyna Podgórska, Agnieszka Nowak and Zygmunt Pejsak
The aim of the study was to implement in vitro cultivation of L. intracellularis strains using ATCC 55783 and vaccine strains, and McCoy cells (ATCC CRL-1696). The infection was monitored by daily observations under phase contrast microscope. Indirect immunostaining using monoclonal antibody was also performed. Large number of S-shaped, moving bacteria were found in the cell medium in cultures infected with ATCC 55783 and vaccine strain. Immunostaining revealed a high number of multiple cell-associated or intracellular red stained bacteria in the infected cultures. This study describes for the first time in vitro cultivation of L. intracellularis in Poland, which creates further perspective for more advanced research on this bacterium.
Andrzej Kowalczyk, Edyta Kozak, Magdalena Łyjak, Zygmunt Pejsak and Krzysztof Niemczuk
Macrophages and cytokines are important in the control of inflammation and regulation of the immune response. However, they can also contribute to immunopathology in the host after viral infection and the regulatory network can be subverted by infectious agents, including viruses, some of which produce cytokine analogues or have mechanisms that inhibit cytokine function. African swine fever virus (ASFV) encodes a number of proteins which modulate cytokine and chemokine induction, host transcription factor activation, stress responses, and apoptosis. The aim of this review is to elucidate the mechanisms of immune responses to ASFV in different subpopulations of porcine macrophages. A transcriptional immune response in different resident tissue macrophages following ASFV infection was presented in many publications. ASFV-susceptible porcine macrophages can be of several origins, such as peripheral blood, lungs, bone marrow, etc. blood monocytes, blood macrophages, and lung macrophages have demonstrated a modulation of phenotype. Monocyte-derived macrophages could express surface markers not found on their monocyte precursors. Moreover, they can undergo further differentiation after infection and during inflammation. When viruses infect such cells, immunological activity can be seriously impaired or modified.
Małgorzata Pomorska-Mól, Iwona Markowska-Daniel, Krzysztof Kwit, Kinga Urbaniak and Zygmunt Pejsak
The kinetics of C-reactive protein (CRP), haptoglobin (Hp), serum amyloid A (SAA), and pig major acute protein (Pig-MAP) response in pigs co-infected with H3N2 swine influenza virus (SwH3N2) and Bordetella bronchiseptica (Bbr) was studied, with assessment of potential correlations between the concentration of acute phase proteins (APPs) in serum samples, lung lesions, and the clinical course of the disease in co-infected pigs. The standard bacteriological methods for detection of Bbr and PCR technique for identification of Bbr and SwH3N2 were used. The serum concentrations of APPs were measured using ELISA. The concentration of CRP, SAA, and Pig-MAP was significantly higher from 2 to 4 or 5 dpi. The concentration of Hp was elevated until the end of the study. Significant correlations were found between the serum concentration of SAA and Pig-MAP and clinical score, and between the concentration of SAA and lung score. Apart from their potential as biological markers for co-infections, SAA and Pig-MAP levels have additive value since they are related to the severity of infection. The results indicate that measurement of APP (i.e SAA) may prove valuable in assessing the severity of respiratory infection in pigs, and may be of supportive value in the clinical evaluation of animals and in the selection of more appropriate treatment.
Andrzej Kowalczyk, Kinga Urbaniak, Iwona Markowska-Daniel and Zygmunt Pejsak
The aim of the study was to monitor genetic diversity and antigenic changes in the genome of influenza A(H1N1)pdm09 viral isolates detected during the post-pandemic period in Poland. Clinical specimens obtained from three suspected cases of influenza were analysed by sequencing. Among the differences identified in amino acids sequences, nine substitutions were located within the antigenic HA1 sites and in five residues forming receptor-binding pocket. The HA(D222G) mutation was shown in the isolate Swine/Poland/134312/12 obtained from a mild case of the disease. It must be emphasized that, in general, clinically mild cases are caused by the viruses in which that specific mutation, i.e. haemagglutinin (D222G), does not occur.
Ning Jia, Yunwen Ou, Zygmunt Pejsak, Yongguang Zhang and Jie Zhang
African swine fever virus (ASFV) is a large, double-stranded DNA virus and the sole member of the Asfarviridae family. ASFV infects domestic pigs, wild boars, warthogs, and bush pigs, as well as soft ticks (Ornithodoros erraticus), which likely act as a vector. The major target is swine monocyte-macrophage cells. The virus can cause high fever, haemorrhagic lesions, cyanosis, anorexia, and even fatalities in domestic pigs. Currently, there is no vaccine and effective disease control strategies against its spread are culling infected pigs and maintaining high biosecurity standards. African swine fever (ASF) spread to Europe from Africa in the middle of the 20th century, and later also to South America and the Caribbean. Since then, ASF has spread more widely and thus is still a great challenge for swine breeding. The genome of ASFV ranges in length from about 170 to 193 kbp depending on the isolate and contains between 150 and 167 open reading frames (ORFs). The ASFV genome encodes 150 to 200 proteins, around 50 of them structural. The roles of virus structural proteins in viral infection have been described. These proteins, such as pp220, pp62, p72, p54, p30, and CD2v, serve as the major component of virus particles and have roles in attachment, entry, and replication. All studies on ASFV proteins lay a good foundation upon which to clarify the infection mechanism and develop vaccines and diagnosis methods. In this paper, the roles of ASFV structural proteins in viral infection are reviewed.
Małgorzata Pomorska-Mól, Ewelina Czyżewska-Dors, Krzysztof Kwit and Zygmunt Pejsak
Introduction: The aim of the study was to explore the effect of enrofloxacin on production of selected cytokines by porcine peripheral blood mononuclear cells (PBMCs).
Material and Methods: Twenty pigs (10 control and 10 experimental) were used in this research. Pigs from experimental group received enrofloxacin at therapeutic doses. Blood samples were collected before, during, and after treatment with enrofloxacin. PBMCs were incubated with or without lipopolysaccharide (LPS). Production of IL-6, IL-10, INF-γ, and TNF-α were determined by ELISA.
Results: Administration of enrofloxacin to healthy pigs for 5 d induced a transient reduction of the PBMCs response to LPS in terms of IL-6 and TNF-α secretion. The concentration of IL-6 returned to the day 0 level shortly after treatment, while TNF-α production remained reduced for 10 d after the treatment. The production of IL-10 was not affected by enrofloxacin. The level of IFN-γ was below the detection limit of the tests.
Conclusion: The results indicate that enrofloxacin administered in vivo in therapeutic doses has an immunomodulatory effect through its capacity to inhibit secretion of IL-6 and TNF-α by porcine PBMC stimulated by LPS.
Ewelina Czyżewska-Dors, Krzysztof Kwit, Zygmunt Pejsak and Małgorzata Pomorska-Mól
Introduction: The aim of the study was to evaluate the effect of administration of therapeutic doses of ceftiofur and tulathromycin on the circulating lymphocyte subpopulations in healthy pigs. Material and Methods: The study was conducted on thirty healthy 7- to 10-week-old pigs, assigned to three groups: the TUL group, injected with tulathromycin (n = 10); the CEF group, injected with ceftiofur (n = 10); and the C group, the control with no antibiotic administration (n = 10). Blood samples were collected before, during, and after treatment with antimicrobials. Lymphocyte subpopulations circulating in the blood were determined by immunostaining and flow cytometry analyses. Results: Following administration of a therapeutic dose of tulathromycin, there were no changes in the lymphocyte subpopulations circulating in blood. In contrast, administration of ceftiofur at the recommended dose decreased the absolute number of CD3+, CD21+, CD4+CD8-, CD4-CD8+, and double positive CD4CD8 cells. Conclusion: Results from the study indicate that ceftiofur possesses the ability to modulate the immune system in healthy pigs by decreasing lymphocyte subpopulations circulating in blood.