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During last 15 years at least 38 species from 16 genera of plant viruses were detected and identified in environmental waters, such as rivers, streams, ponds, lakes and in the sea. Infectious virus particles were found in field and greenhouse irrigation systems, hydroponic cultures, manure nutrient solutions, and even in semi-liquid sludge of sewage plants. Plant viruses were also detected in tap water, fogs and in the clouds. Presented paper reviews: - the methods used for detecting plant viruses in waters samples, - the forms and stages of infectious plant viruses in natural waters, - methods of long distance water-transmission of plant viruses including the origins of virus particles in surface waters and mechanisms of plant infections, - epidemiological consequences of water-born and air-born plant virus discovery.
The purpose of the studies was to assess the spread of BHV-1 infection in dairy cows. Clinical, virological and serological examinations were carried out in two stages within four years. Numerous clinical and asymptomatic cases of pustular vulvovaginitis were found in the herds under study. Serologic results showed that all the herds were infected (4.9 - 56.6%). The findings revealed a higher dynamics of infection spread in herds with low numbers of infected animals than in those with a high percentage of cows having specific antibodies against BHV-1. The results indicated that most cows aged 3-5 years had SN antibodies against BHV-1.
This work describes the role of membrane bridges in the spread of ectromelia virus (ECTV) Moscow strain (ECTV-MOS) in vitro in BALB/3T3 and Vero cells. In this research, immunofluorescence techniques were used: cells were fixed, stained for the presence of viral antigens, F-actin, and DNA, and viewed under a fluorescence microscope. In both cell lines, ECTV-MOS infection induces production of two types of actin-rich protrusions: tiny actin tails or long filopodia-like structures. It appears that both types contribute to the spread of ECTV-MOS particles and may be classified as membrane bridges.
The worldwide dissemination of HIV, the cause of AIDS, over the past 25 years has been one of the most catastrophic examples of the emergence, transmission, and propagation of a zoonotic infection. Ongoing exposure of humans to simian lentiviruses and the potential for additional lentiviral epidemics should not be dismissed.
The characteristics of the avian influenza viruses (AIV) have been presented, including their classification, structure and variability mechanisms. Depending on their pathogenicity they were divided into highly pathogenic (HP) and low pathogenic (LP) pathotypes. The definition of avian influenza according to the directive of the European Union was cited, indicating, among others, that HP strains emerge exclusively from H5 and H7 subtypes. The change takes place in poultry and not in wild birds. The outbreak of HPAI H5N1 in South East Asia at the end of 2003, which spread during subsequent years to Asia, Europe and Africa, has put an increased focus on wild, migratory birds that participated each in year seasonal flights. The cited literature indicates that these birds, representing a very large number of species, are carriers of LPAI strains, not being pathogenic for poultry and man. However, if these birds, particularly ducks, survive infection with highly pathogenic avian influenza strains they are able to fly for long distances, while simultaneously being carriers of HPAI H5N1. In such cases they may spread the pathogenic virus intercontinentally. Because of the difficulties in identification of carriership of avian influenza viruses in migrating birds, their role in spreading HPAI H5N1 is not fully clear and needs further investigation. According to the present point of view the probability of causing avian influenza in poultry in connection with migratory birds ranges from low to high with a high degree of uncertainly. The risk of infection of poultry kept in free-range conditions is high with a medium uncertainty of infection and disease.
The Schmallenberg virus (SBV), as a new for Europe Ortobuniaviridae genus member, emerged in Poland in 2012, spreading rapidly across the country. Serological monitoring revealed a continuous increase of seropositivity among farm ruminants; moreover, the virus was detected in the insect vector, i.e. biting midges in different regions. The sylvatic cycle of SBV infections cannot be ruled out due to the detection of SBV antibodies in 24% of free living ruminants. Breeding losses related to SBV infection are difficult to estimate because of the lack of regulations for mandatory notifications. Furthermore specific symptoms associated with congenital malformations in newborns are observed only in a small percentage of intrauterine infections. Due to the current restrictions or bans on the export of animals resulting from SBV infection significant economic losses are recorded. The emergence of a new, never previously detected in Europe arbovirus raises a number of questions about its manner of transmission, vector ecology, the possibility of its spread and prevention as well as control of the diseases.
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