Using shared needles for subcutaneous inoculation can transmit bluetongue virus mechanically between ruminant hosts

Bluetongue virus (BTV) is an economically important arbovirus of ruminants that is transmitted by Culicoides spp. biting midges. BTV infection of ruminants results in a high viraemia, suggesting that repeated sharing of needles between animals could result in its iatrogenic transmission. Studies defining the risk of iatrogenic transmission of blood-borne pathogens by less invasive routes, such as subcutaneous or intradermal inoculations are rare, even though the sharing of needles is common practice for these inoculation routes in the veterinary sector. Here we demonstrate that BTV can be transmitted by needle sharing during subcutaneous inoculation, despite the absence of visible blood contamination of the needles. The incubation period, measured from sharing of needles, to detection of BTV in the recipient sheep or cattle, was substantially longer than has previously been reported after experimental infection of ruminants by either direct inoculation of virus, or through blood feeding by infected Culicoides. Although such mechanical transmission is most likely rare under field condition, these results are likely to influence future advice given in relation to sharing needles during veterinary vaccination campaigns and will also be of interest for the public health sector considering the risk of pathogen transmission during subcutaneous inoculations with re-used needles

The problem of eliminating false alarms in computer systems for the protection of peripheral

W artykule rozpatruje się problem ochrony obiektów powierzchniowych za pomocą komputerowego systemu ochrony peryferyjnej, sterującego ochroną utworzoną w postaci barykady z wmontowanymi w nią czujkami naciągowymi. Analizuje się problem fałszywych alarmów w tego typu systemach ochrony, które mają charakter losowy oraz ciągły i zmienny w czasie. Opisuje się w sposób formalny za pomocą procesu stochastycznego zachowanie barykady podczas oddziaływania na nią czynników losowych i formułuje się i rozwiązuje zadanie określenia czułości czujek naciągowych minimalizujących powstawanie fałszywych alarmów.The article examines the problem of protection of surface objects via a computer security system peripheral control security barricades set up in the form of integrated in its take-detectors. Examines the problem of false alarms in this type of protection systems, which are random and continuous and yariable over time. Described in a formal way through a process of stochastic behavior of the barricade at the impact of random factors, and it is formulated and solves the task of determining the sensithdty of the detectors tightening to minimize the formation of false alarms

Evaluation of the PageRank algorithm effectiveness

In this paper the challenges in building good search engines are discussed. Many of the search engines use well-known information retrieval algorithms and techniques. They use Web crawlers to maintain their index databases amortizing the cost of crawling and indexing over the millions of queries received by them. Web crawlers are programs that exploit the graph structure of the Web to move from page to page. Paper analyses the PageRank algorithm one of these Web crawlers. The results of the impact of the PageRank parameter value on the effectiveness of determining the so-called PageRank vector are considered in the paper. Investigations are illustrated by means of the results of a some simulation experiments to analyze the PageRank algorithm efficiency for different density graph (representing analyzed part of www) coefficient values

The pathology and pathogenesis of bluetongue.

Bluetongue (BT) is an insect-transmitted viral disease of wild and domestic ruminants and, occasionally, other species. Amongst domestic livestock, BT is most common in certain breeds of sheep whereas asymptomatic BT virus (BTV) infection of cattle is typical in enzootic regions. BT in cattle can be a feature of specific outbreaks, notably the current epizootic in Europe caused by BTV serotype 8. BTV replicates within mononuclear phagocytic and endothelial cells, lymphocytes and possibly other cell types in lymphoid tissues, the lungs, skin and other tissues. Infected ruminants may exhibit a prolonged but not persistent viraemia and BTV is associated with erythrocytes during the late stages of this prolonged viraemia. The pathogenesis of BT involves injury to small blood vessels in target tissues, but the relative contributions of direct virus-induced cytolysis and virus-induced vasoactive mediators in causing endothelial injury and dysfunction are presently unclear. The lesions of BT are characteristic and include: haemorrhage and ulcers in the oral cavity and upper gastrointestinal tract; necrosis of skeletal and cardiac muscle; coronitis; subintimal haemorrhage in the pulmonary artery; oedema of the lungs, ventral subcutis, and fascia of the muscles of the neck and abdominal wall; and pericardial, pleural and abdominal effusions. Transplacental transmission of BTV in ruminants, with subsequent fetal infection, is a property of specific virus strains, especially those propagated in embryonated eggs or cell culture. The outcome of BTV infection of fetal ruminants is age-dependent, with distinctive cavitating lesions of the central nervous system in animals that survive infection in early gestation. Immune competence to BTV arises by mid-gestation, and animals infected in late gestation can be born viraemic and without significant brain malformations

Toggenburg Orbivirus, a new bluetongue virus: Initial detection, first observations in field and experimental infection of goats and sheep

A novel bluetongue virus termed "Toggenburg Orbivirus" (TOV) was detected in two Swiss goat flocks. This orbivirus was characterized by sequencing of 7 of its 10 viral genome segments. The sequencing data revealed that this virus is likely to represent a new serotype of bluetongue virus [Hofmann, M.A., Renzullo, S., Mader, M., Chaignat, V., Worwa, G., Thuer, B., 2008b. Genetic characterization of Toggenburg Orbivirus (TOV) as a tentative 25th serotype of bluetongue virus, detected in goats from Switzerland. Emerg. Infect. Dis. 14, 1855-1861]. In the field, no clinical signs were observed in TOV-infected adult goats; however, several stillborn and weak born kids were reported. Although born during a period of extremely low vector activity, one of these kids was found to be antibody and viral genome positive and died 3.5 weeks postpartum. Experimental infection of goats and sheep, using TOV-positive field blood samples, was performed to assess the pathogenicity of this virus. Goats did not show any clinical or pathological signs, whereas in sheep mild bluetongue-like clinical signs were observed. Necropsy of sheep demonstrated bluetongue-typical hemorrhages in the wall of the pulmonary artery. Viral RNA was detected in organs, e.g. spleen, palatine tonsils, lung and several lymph nodes of three experimentally infected animals. Unlike other bluetongue virus serotypes, it was not possible to propagate the virus, either from naturally or experimentally infected animals in any of the tested mammalian or insect cell lines or in embryonated chicken eggs. In small ruminants, TOV leads to mild bluetongue-like symptoms. Further investigations about prevalence of this virus are needed to increase the knowledge on its epidemiology

In vivo and in vitro propagation and transmission of Toggenburg orbivirus

The Toggenburg orbivirus (TOV), a recently discovered virus related to bluetongue virus (BTV), has been identified in goats in Switzerland, Italy and Germany. Isolation of TOV in vitro has not yet been achieved and the transmission mechanisms are still unknown. In the experimental infection of pregnant goats described here, TOV could not be detected in secretion/excretion samples or fetal blood. Material from the goat experiment was used as inoculum for propagating the virus in vitro. To enhance the infectivity of TOV several modified protocols, e.g. pretreatment of the virus with trypsin, polyethylene glycol-mediated infection and lipofection were applied. Isolation of TOV, attempts to infect Culicoides nubeculosus by feeding TOV-positive blood and intracerebral inoculation of newborn mice were unsuccessful. The results of these studies suggest that TOV requires specific but different factors than other BTVs for infection and replication outside of its natural caprine host

Virological and pathological findings in Bluetongue virus serotype 8 infected sheep

Twenty-seven sheep of the four most common Swiss breeds and the English breed Poll Dorset were experimentally infected with a northern European field strain of bluetongue virus serotype 8 (BTV-8). Animals of all breeds eveloped clinical signs, viremia and pathological lesions, demonstrating that BTV-8 is fully capable of replicating and inducing bluetongue disease (BT) in the investigated sheep. Necropsy performed between 10 and 16 days post-infectionem (d.p.i.) revealed BT-typical hemorrhages, effusions, edema, erosions and activation of lymphatic tissues. Hemorrhages on the base of the Arteria pulmonalis and the left Musculus papillaris subauricularis were requently present. Histology confirmed the macroscopical findings. Using a score system, clinical manifestation and pathology were found to be significantly related. Furthermore, clinical signs and fever were shown to be indicative for the concurrent presence of high amounts of viral ribonucleic acid (RNA) in blood. Spleen, lung, lymph nodes and tonsils from all animals were analyzed regarding viral RNA loads and infectivity using real-time reverse transcriptase PCR (rRT-PCR) and virus isolation in cell culture, respectively. The highest amount of viral RNA was detected in spleen and lung and rRT-PCR revealed to be amore sensitive method for virus detection compared to virus isolation. A long-term follow-up was performed with three sheep showing that BTV-8 viral RNA in blood was present up to 133 d.p.i. and in certain tissues even on 151 d.p.i. No significant breed-related differences were observed concerning clinicopathological picture and viremia, and the Swiss sheep were as susceptible to BTV-8 infection as Poll Dorset sheep, demonstrating a remarkably high virulence of BTV-8 for indigenous sheep breeds