Transplacental Transmission of Bluetongue Virus Serotype 1 and Serotype 8 in Sheep: Virological and Pathological Findings

The Bluetongue virus serotype 8 (BTV-8) strain, which emerged in Europe in 2006, had an unusually high ability to cause foetal infection in pregnant ruminants. Other serotypes of BTV had already been present in Europe for more than a decade, but transplacental transmission of these strains had never been demonstrated. To determine whether transplacental transmission is a unique feature of BTV-8 we compared the incidence and pathological consequences of transplacental transmission of BTV-8 to that of BTV-1. Nine pregnant ewes were infected with either BTV-8 or BTV-1. The BTV strains used for the infection were field strains isolated on embryonated chicken eggs and passaged twice on mammalian cells. Blood samples were taken to monitor the viraemia in the ewes. Four weeks after the infection, the foetuses were examined for pathological changes and for the presence of BTV. BTV-8 could be demonstrated in 12 foetuses (43%) from 5 ewes (56%). %). BTV-1 was detected in 14 foetuses (82%) from 6 ewes (67%). Pathological changes were mainly found in the central nervous system. In the BTV-8 group, lympho-histiocytic infiltrates, gliosis and slight vacuolation of the neuropil were found. BTV-1infection induced a severe necrotizing encephalopathy and severe meningitis, with macroscopic hydranencephaly or porencephaly in 8 foetuses. In our experimental setting, using low passaged virus strains, BTV-1 was able to induce transplacental transmission to a higher incidence compared to BTV-8, causing more severe pathology

Transplacental transmission of BTV-8 in sheep: BTV viraemia, antibody responses and vaccine efficacy in lambs infected in utero

Bluetongue virus (BTV) is an insect vector transmitted virus which causes an economically important disease in ruminants. BTV infection during pregnancy can result in infection of the foetus, which may lead to the birth of persistently infected or immunotolerant offspring. Since persistently infected animals continuously produce large amounts of virus they could be a source of infection for the insect vector. This could significantly influence the epidemiology of the virus and hence might require additional measures to control a BTV outbreak. Therefore, we investigated the potential of BTV-8 to induce persistent infection or immunotolerance in lambs in an experimental setting. Infection of eighteen 70-75 days pregnant ewes with wild type BTV-8 led to the birth of 25 out of 44 BTV RNA positive lambs (foetal infected, FI). All 23 FI lambs born alive also had anti BTV antibodies at birth; infectious virus could be recovered from 5 out of 25 FI lambs. Viral RNA loads decreased rapidly after birth; 19 out of 20 FI lambs that remained in the experiment until week 14 after birth, were RNA negative at that time. Since persistence of BTV-8 infection could not be demonstrated, we investigated whether foetal infection had an effect on protection against a field virus infection and on efficacy of vaccination. To this end, 5 FI lambs and 5 foetal non-infected (FNI) lambs were vaccinated with the inactivated Bovilis(®) BTV-8 vaccine, five months after birth. Three weeks after the vaccination, all lambs were infected with wild type BTV-8. The foetal infection did not interfere with vaccination efficacy. In contrast, foetal BTV-8 infection induced an immune response which afforded protection against BTV challenge comparable to the level of protection induced by vaccination

Transplacental transmission of BTV-8 in sheep: BTV viraemia, antibody responses and vaccine efficacy in lambs infected in utero

Bluetongue virus (BTV) is an insect vector transmitted virus which causes an economically important disease in ruminants. BTV infection during pregnancy can result in infection of the foetus, which may lead to the birth of persistently infected or immunotolerant offspring. Since persistently infected animals continuously produce large amounts of virus they could be a source of infection for the insect vector. This could significantly influence the epidemiology of the virus and hence might require additional measures to control a BTV outbreak. Therefore, we investigated the potential of BTV-8 to induce persistent infection or immunotolerance in lambs in an experimental setting. Infection of eighteen 70-75 days pregnant ewes with wild type BTV-8 led to the birth of 25 out of 44 BTV RNA positive lambs (foetal infected, FI). All 23 FI lambs born alive also had anti BTV antibodies at birth; infectious virus could be recovered from 5 out of 25 FI lambs. Viral RNA loads decreased rapidly after birth; 19 out of 20 FI lambs that remained in the experiment until week 14 after birth, were RNA negative at that time. Since persistence of BTV-8 infection could not be demonstrated, we investigated whether foetal infection had an effect on protection against a field virus infection and on efficacy of vaccination. To this end, 5 FI lambs and 5 foetal non-infected (FNI) lambs were vaccinated with the inactivated Bovilis(®) BTV-8 vaccine, five months after birth. Three weeks after the vaccination, all lambs were infected with wild type BTV-8. The foetal infection did not interfere with vaccination efficacy. In contrast, foetal BTV-8 infection induced an immune response which afforded protection against BTV challenge comparable to the level of protection induced by vaccination

A novel guinea pig model of Chlamydia trachomatis genital tract infection

Contains fulltext : 95582.pdf (publisher's version ) (Closed access)Genital Chlamydia trachomatis infections often result in pelvic inflammatory disease and sequelae including infertility and ectopic pregnancies. In addition to the already established murine models, the development of other animal models is necessary to study the safety and efficacy of prototype vaccine candidates. The intravaginal infection of guinea pigs with C. trachomatis has been tested in three independent studies. The first two studies investigated the effect of hormonal treatment of the animals prior to infection with serovars D and E. The results showed that estradiol treatment was required for sustained infection. The third study conducted an immunization-challenge experiment to explore the feasibility of measuring protection in this guinea pig model. C. trachomatis bacteria were sampled using vaginal swabs and measured by qPCR. Using immunohistochemistry the bacteria were detected in the oviducts 19 days post-infection, indicating that the estradiol treatment resulted in ascending infection. Furthermore, immunization of guinea pigs with live EB formulated with ISCOM matrix led to reduction of cervico-vaginal shedding and diminished the severity of pathology. In this study we have developed a new guinea pig model of C. trachomatis female genital tract infection for the purpose of evaluating potential vaccine candidates

Diversity in news recommendation:Manifesto from Dagstuhl Perspectives Workshop 19482

News diversity in the media has for a long time been a foundational and uncontested basis for ensuring that the communicative needs of individuals and society at large are met. Today, people increasingly rely on online content and recommender systems to consume information challenging the traditional concept of news diversity. In addition, the very concept of diversity, which differs between disciplines, will need to be re-evaluated requiring an interdisciplinary investigation, which requires a new level of mutual cooperation between computer scientists, social scientists, and legal scholars. Based on the outcome of a interdisciplinary workshop, we have the following recommendations, directed at researchers, funders, legislators, regulators, and the media industry: - Conduct interdisciplinary research on news recommenders and diversity. - Create a safe harbor for academic research with industry data. - Strengthen the role of public values in news recommenders. - Create a meaningful governance framework for news recommenders. - Fund a joint lab to spearhead the needed interdisciplinary research, boost practical innovation, develop reference solutions, and transfer insights into practice