European Brown Hare Syndrome in Poland: Current Epidemiological Situation.

European brown hare syndrome (EBHS) is one of the main causes of mortality in brown hares () and mountain hares () in Europe. Since the mid-1990s, this highly lethal and contagious plague has been widespread in many European countries, contributing to a drastic decline in the number of free-living and farmed hares. A second lagovirus, able to infect some species of hares is rabbit haemorrhagic disease virus 2 (RHDV2; GI.

Evidence of independent introductions of RHDV2 strains in Poland based on the genome analysis of viral isolates from 2016-2018.

The aim of this study was the molecular epidemiology of independently introduced RHDV2 strains in Poland. The nucleotide sequences of RHDV2 diagnosed in domestic rabbits in 2018 in the voivodeships of Swietokrzyskie (strain PIN), Malopolskie (strain LIB) and Mazowieckie (strain WAK), and RHDVa from 2015 (strain F77-3) recognized in wild rabbits in Kujawsko-Pomorskie voivodeship were compared to the genome sequences of the first native RHDV2 strains from 2016-2017. The reference sequences available in public databases, the representative for a classical RHDV (G1-G5 genogroups), RHDVa (G6), non-pathogenic caliciviruses (RCV, GI.

Detection of rabbit haemorrhagic disease virus 2 (GI.2) in Poland.

In this paper we present the first cases of rabbit haemorrhagic disease virus 2 (RHDV2 - GI.2) in Poland. The virus was detected in liver samples of RHD-suspected rabbits from Lodzkie and west Pomeranian voivodeships.

Phylogenetic analysis of rabbit haemorrhagic disease virus (RHDV) strains isolated in Poland.

The aim of this study was to characterise the nucleotide and amino acid sequence of complete genomes (7.5 kb) from RHDV strains isolated in Poland and estimate the genetic variability in different elements of the viral RNA. In addition, the sequence of Polish RHDV isolates isolated from 1988-2015 was compared with the sequences of other European RHDV, including the RHDVa and RHDV2/RHDVb subtypes.

Serological Survey for RHD Antibodies in Rabbits from Two Types of Rabbit Breeding Farms.

Seroprevalence studies of RHDV antibodies in domestic rabbits were conducted between 2008-2014. A total of 12,169 sera from the provinces of central, southern and south-east Poland, including 7,570 samples collected from mixed-breed rabbits reared in smallholder farms and nearly 4,600 sera taken mainly from unvaccinated rabbits kept in industrial farms, were examined using ELISA tests. Additionally, cross-reactivity of selected tested and control archival sera using both classic RHDV and RHDVa antigens was determined by HI assay.

Bluetongue in Europe and the role of wildlife in the epidemiology of disease.

The article reviews a current bluetongue (BT) epidemiological situation in Europe, BT restricted zones and the role of wild ungulates as a reservoir for bluetongue virus (BTV) and its transmission. BT has been eradicated from central and northern Europe, however it is still circulating in some regions of southern and south-eastern Europe. According to the recent information of the Directoriate General for Health and Consumer Affairs (DG SANCO) disease caused by BTV1 was spreading at the beginning of 2014 in Corsica (France).

The evolution of bluetongue virus: genetic and phenotypic diversity of field strains.

Bluetongue virus (BTV), the aetiological agent of bluetongue (BT), is a small (about 70 nm in diameter) icosahedral virus with a genome composed of ten linear segments of double-stranded RNA (dsRNA), which is packaged within an icosahedral nucleocapsid composed of seven structural proteins. The BTV genome evolves rapidly via genetic drift, reassortment of genome segments (genetic shift) and intragenic recombination. This evolution, and random fixation of quasispecies variants during transmission of BTV between susceptible animals and vectors appear to be the main mechanism leading to the observed genetic diversity amongst BTV field strains.

Identification of Polish RHDVa subtype strains based on the analysis of a highly variable part of VP60 gene.

In order to determine the genetic variability of Polish RHD virus strains and to confirm the presence of genetic variant (RHDVa) subtype the partial nucleotide sequences of capsid protein gene, including two highly variable regions C and E, were examined. Phylogenetic analyses of 15 viral strains obtained over 18 years revealed the presence of three genetic groups. The oldest RHDV strains exhibit very close amino acid sequence similarity (98-99%) to the German FRG89 reference strain and most of European strains of the same period, as well as Chinese isolate from 1984.

Bluetongue vaccines in Europe.

The article reviews the history, present status and the future of BT vaccines in Europe. So far, an attenuated (modified live viruses, MLV) and inactivated virus vaccines against BT were developed and used in the field. Moreover, the virus-like particles (VLPs) produced from recombinant baculovirus, and live recombinant vaccinia or canarypox virus-vectored vaccines were tested in the laboratory.

Evaluation of commercial ELISA kits for the detection of antibodies against bluetongue virus.

The aim of this study was to estimate the diagnostic value of different commercially available ELISA kits for the detection of bluetongue virus (BTV) antibodies in infected and vaccinated animals. The relative specificity of ELISA kits was evaluated using a panel of sera originating from healthy cattle, never vaccinated nor exposed to BTV. All ELISA kits applied had a high relative specificity (99.

Monitoring studies of bluetongue disease in ruminants imported to Poland from EU.

The results of 4-year serological and 2-year virological monitoring studies of bluetongue (BT) disease in ruminants imported to Poland from EU countries are presented. Sera were screened using the c-ELISA and direct ELISA tests. Out of 49587 samples of sea, 3385 (6.

Application of real-time reverse transcription polymerase chain reaction for the detection of SVDV.

Application of real-time RT-PCR (rRT-PCR) for detection of swine vesicular disease virus (SVDV) in samples of archival SVDV isolates and clinical samples collected from SVDV infected pigs was described. A primer set that targets the IRES region of the SVDV genome and TaqMan probe specific for a highly conserved region in SVDV RNA IRES region were used. The assay detected viral RNA in all tested archival strains of SVDV isolated in Europe during years 1972-73 and 1992 as well as in clinical samples collected from experimentally infected pigs.

Seroprevalence of antibodies against bluetongue virus in animals imported to Poland from EU countries.

The aim of this study was to determine the seroprevalence of BTV-specific antibodies in animals imported to Poland from EU countries after 15 June 2006. From 1 January 2007 to 22 January 2008, a total of 10719 samples of sera collected from cattle, goats and fallow deer were tested. Sera were screened using the highly sensitive and specific c-ELISA test and positive results were confirmed by the AGID assay.

Detection of foot-and-mouth disease virus infection in vaccinated cattle.

The aim of this study was to evaluate the value of commercially available kits for the detection of foot-and-mouth disease (FMD) virus infection in vaccinated cattle. The cattle were vaccinated with a commercial aqueous FMD vaccine type A24 and subsequently challenged 28 days post vaccination with homologous FMD virus. Seven of eight animals were protected from clinical disease and all became carriers.

Prevalence of seroreagents to FMDV in the cattle population in Poland: results of 9-year monitoring studies.

The aim of this study was to evaluate the occurrence of antibodies to foot-and-mouth disease virus (FMDV) in sera of cattle in Poland. The examinations were performed using the virus neutralization (VN) test and ELISA methods: liquid-phase blocking ELISA (LPBE) and 3ABC-ELISA. During 1993-2001, about 681,000 samples of sera collected from animals held on the territory of Poland were tested.

Quantitation of foot-and-mouth disease virus genomes in bovine tissue by competitive RT-PCR.

The sensitivity of a reverse transcription-dependent polymerase chain reaction (RT-PCR) for detecting foot-and-mouth disease virus (FMDV) genomes was quantified by use of RNA transcribed in vitro from FMDV-specific cDNA. Previously, the cDNA had been elongated by 228 base pairs. The minimum number of template molecules required to obtain the specific RT-PCR product was determined to be 10(4).

A new variant of the viral haemorrhagic disease of rabbits virus.

A new variant of viral haemorrhagic disease of rabbits (VHD) virus, recently detected in Poland and called Blaszki (BLA), gives positive results in enzyme-linked immunosorbent assay (ELISA) and exhibits viral protein of 60 kilodaltons (VP 60), as detected by Western blot analysis. This BLA variant of VHD virus has caused high morbidity and mortality in rabbits, as have other reported variants with similar clinical signs and pathological lesions, but-in contrast to other variants-the BLA variant gave negative results in the haemagglutination test. This development indicates the limitations of haemagglutination testing in the diagnosis of VHD.

Foot-and-mouth disease virus O1Lombardy is biochemically related to O2 isolates.

The capsid protein VP1-encoding RNA regions of the foot-and-mouth disease virus isolates O1Lombardy/1946 and O2Brescia/1947 were sequenced and found to be closely related to each other and to O2Normandy/1949, despite some sequence differences. The O1Lombardy sequence was expected to be more closely related to those of the subtype O1 isolates of 1965 and later (e.g.

Effect of prolactin, progesterone, pregnancy and lactation on DNA synthesis and DNA polymerase activities in rabbit mammary gland.

DNA synthesis and DNA polymerase-alpha, -beta and -gamma activities in the rabbit mammary gland were studied during hormone-directed cellular growth. It was found that during pregnancy, early lactation and after injection of prolactin, changes in the activity of DNA polymerase-alpha paralleled the rate of mammary gland DNA synthesis. It was also found that the amount of polymerase-alpha activity bound to isolated chromatin depended on the physiological state of the animal.

DNA polymerases of rabbit mammary gland: partial purification, characterization and changes in DNA polymerase activities as a function of physiological state.

DNA polymerases alpha and beta were partially purified from rabbit mammary gland, and their properties were examined. Many of these properties (sedimentation coefficients, pH optima, divalent cation requirements, sensitivity to various inhibitors) are similar to those commonly regarded as typical of eukaryotic DNA polymerases alpha and beta. Effect of stage of pregnancy and lactation on the levels of activity of DNA polymerases alpha, beta and gamma in rabbit mammary gland was examined.

Calcium and insulin in the regulation of DNA synthesis in mouse mammary gland studied in organ culture.

The interaction of calcium and insulin was investigated in mouse mammary gland organ culture by analysis of the time-course of the DNA-synthetic response following delayed addition of insulin or calcium to the culture media. The DNA-synthetic responses were also studied using mammary explants from virgin, pregnant and lactating mice. These experiments have shown that qualitative differences exist in the responsiveness of mammary epithelium to insulin and calcium.

Variation of DNA polymerase activities and DNA synthesis in mouse mammary gland during pregnancy and early lactation.

The rate of DNA synthesis and the activity of DNA polymerases and thymidine kinase were measured during the endocrine-regulated cellular growth and differentiation of mouse mammary gland. Using specific assays, the activity of the DNA polymerases, alpha, beta and gamma, was determined in tissue extracts of mammary glands of mice at various stages of pregnancy and early lactation. In addition, extracts of the mammary tissue of virgin, mid-pregnant and early lactating mice were fractionated on sucrose density gradients, and the activity of DNA polymerase alpha and beta was assayed in the gradient fractions.

Effects of spermidine and spermine on DNA synthesis in isolated nuclei and on the activity of DNA polymerases alpha and beta from the mammary gland of pregnant rabbit.

The rate of [3H]dTMP incorporation by nuclei isolated from the pregnant rabbit mammary gland was affected by polyamines in two distinct ways: a) a general inhibitory effect was evident when spermidine or spermine were added to the incubation mixture at concentrations 10(-3) - 10(-2) M and 10(-4) - 10(-2) M, respectively; and b) a very specific stimulatory effect of either polyamine at a lower concentration which was observed only when the nuclei were incubated in the presence of horse serum. Furthermore, it was demonstrated that 10(-2) M spermine inhibited the activity of the solubilized nuclear DNA polymerases alpha and beta from the mammary gland of pregnant rabbit, separated by sucrose-density-gradient centrifugation and assayed with activated DNA as a template-primer, while spermidine had no effect at any concentration (10(-9) - 10(-2) M tested.

Characterization of DNA polymerases from the mammary gland of pregnant rabbit.

1. The nuclear extract from the mammary gland of pregnant rabbit was shown to contain DNA polymerases alpha, beta and gamma. Polymerases alpha and gamma were found also in the mitochondria-free cytoplasmic fraction.