Atypical status of bovine spongiform encephalopathy in Poland: a molecular typing study

The aim of this study was to analyze molecular features of protease-resistant prion protein (PrPres) in Western blots of BSE cases diagnosed in Poland with respect to a possible atypical status. Confirmed cases were analyzed by Western blotting with several monoclonal antibodies directed at N-terminal and core epitopes of prion protein (PrP). Most cases showed the classical glycoprofile characterized by the dominance of the di- over the monoglycosylated PrPres band, yielding di-/mono- ratios well above 2 and by reactivity with antibodies having their epitopes in bovine PrP region 110-242 (C-type cases). Surprisingly, seven cases of BSE were atypical. Six were classified as L-type based on a slightly lower molecular mass (M-r) of the non- glycosylated band with respect to C-types and a conspicuously low di-/mono- ratio of glycosylated PrPres bands approaching unity. One case was classified as H-type because of a higher M-r of PrPres bands on the blot when compared with C-type cases. A characteristic epitope of H-type PrPres occurred in the 101-110 region of PrP for which only antibody 12B2 had a sufficient affinity. The occurrence of atypical cases only in animals 9 years of age and older raises questions about the mechanisms of prion diseases and the origin of BSE

Variability of non-structural proteins of equine arteritis virus during persistent infection of the stallion

The genetic stability of ORF1a encoding non-structural proteins nsp1, nsp2, nsp3 and nsp4 of equine arteritis virus (EAV) has been analysed for nearly seven years in a persistently infected stallion of the Malopolska breed. Between November 2004 and June 2011, 11 semen samples were collected. Viral RNA extracted from semen of this carrier stallion was amplified, sequenced and compared with the sequences of the other known strains of EAV. Sequence analysis of ORF1a showed 84 synonymous and 16 non-synonymous mutations. The most variable part of ORF1a was the region encoding nsp2 protein with 13 non-synonymous substitutions. The degree of amino acid identity between isolates ranged from 98.91 to 100%. Only single non-synonymous mutations were detected in nsp1 (one substitution) and nsp4 (two substitutions). The most stable was nsp3 in which no amino acid substitutions were observed during the whole period of observation

Protein expression changes in cells inoculated with Equine Influenza Virus: antibody microarray analysis

Changes in the level of cellular proteins in cells inoculated with equine influenza virus H7N7 and H3N8 were studied with microarray technique. H3N8 induced pro-apoptotic proteins while H7N7 induced both pro- as well as anti-apoptotic factors. The higher level of some cytoskeleton components and proteins involved in the protein quality control was recorded. Relatively high number of proteins involved in the regulation of transcription was down-regulated. The pattern of changes observed for H7N7 and H3N8 may reflect differences in the biological properties of both serotypes

Influenza virus proteins as factors involved in interspecies transmission

Influenza A viruses cause recurrent epidemics and global pandemics. One of the unique features of influenza virus is the ability to overcome interspecies barrier. Reassortment of viral genes and the accumulation of mutations contribute to the emergence of new influenza virus variants. The replication of influenza A virus in a specific host depends on many factors e.g. activity of viral proteins, host response system and environmental conditions. In this review the role of viral proteins as a condition for crossing the species barriers is discussed

First report on equine herpesvirus type 4 isolation in Poland – evaluation of diagnostic tools

Upper respiratory tract infections are still a serious problem in breeding and racing horses. The most common virological factors are EHV1 and EHV4, which are both a major cause of secondary infections. High EHV4 seroprevalence in Polish horses indicates a high transmission rate of this pathogen among horses and increases the need for proper diagnostics. The aim of this study was to develop a reliable laboratory diagnostic scheme for upper respiratory tract infections and to describe the first isolation of EHV4 in Poland. Twenty one nasal swabs collected from young horses under the age of 2 years showing clinical signs of equine rhinopneumonitis were tested with duplex PCR for simultaneous detection and differentiation between EHV1/EHV4. Positive samples were then subjected to virus isolation in Vero cells. Additionally, real-time PCR was developed which allowed viral copy numbers to be quantified and enabled defining that a DNA load below 10³ copies per 1 ml of the sample reflected latent infection or decline of the disease. However, the sensitivity of traditional PCR proved to be sufficient in the diagnostic of the lytic infections and allowed identification of 10 EHV4 infected horses from which 3 strains were successfully isolated in cell culture. Another four EHV4 positive results were obtained by real-time PCR; but, a high Ct (threshold cycle) and a low virus DNA copy number suggested a latent infection. This report describes the first successful isolation of EHV4 from Polish horses