Mucosal lesions in a sheep infected with the Border Disease Virus (BDV)

A 28-week-old sheep was presented at the animal hospital because of chronic emaciation, anemia and slight diarrhea. Due to poor general condition and bad prognosis the animal was euthanized and submitted for postmortem investigation. Multiple erosions and ulcerations were found in the dorsal region of the tongue, the pharynx, the hard palate, in the esophagus and the ruminal pillars. Histologically, these lesions consisted of necrosuppurative inflammation. The animal was tested positive for pestivirus antigen both by immunohistochemical and by virological examination (cell culture, antigen capture ELISA and RT-PCR). A non-cytopathic Border Disease Virus was identified, and sequencing revealed a virus belonging to the BDV-3 cluster. Based on the macroscopical, histological, immunohistological and virological results this case was diagnosed as Border Disease with mucosal lesions. This is the first report of such a case in Switzerland.

Infecções virais e depressão

OBJETIVO: A associação entre depressão e viroses é estudada há quase dois séculos, com resultados conflitantes. O objetivo deste trabalho é fazer uma análise crítica dos estudos existentes na literatura sobre essa relação. MÉTODOS: A pesquisa bibliográfica utilizou as fontes eletrônicas de busca MEDLINE e LILACS (1966 a agosto 2005). As referências dos artigos foram utilizadas como fonte adicional de consulta. RESULTADOS: Foram abordados os trabalhos que trataram da associação entre depressão e os vírus HIV, HCV, EBV, influenza, HSV, HBV, HAV, BDV e HTLV. A relação entre HIV e depressão mostrou-se bem documentada na literatura. Existem indícios de que a prevalência desse transtorno nos indivíduos infectados pelo HIV seja maior que a encontrada nos soronegativos. Além disso, estudos constataram que a depressão está associada a pior prognóstico da infecção. Quanto à associação entre HCV e depressão, os trabalhos sugeriram maior prevalência desse transtorno psiquiátrico nos portadores do HCV comparados à população geral. Não existem evidências científicas suficientes para dar suporte à relação entre os demais vírus e depressão. CONCLUSÃO: As associações mais bem fundamentadas foram aquelas entre depressão e os vírus HIV e HCV. A relação entre as demais viroses e depressão precisa ser mais bem estudada, e trabalhos com delineamento adequado se fazem necessários.

Bornan tauti : masentava enkefalomyeliitti

Summary: Borna disease - a depressing encephalomyelitis

Two different epidemiological scenarios of border disease in the populations of Pyrenean chamois (Rupicapra p. pyrenaica) after the first disease outbreaks

Since 2001 several outbreaks of a new disease associated with Border disease virus (BDV) infection have caused important declines in Pyrenean chamois (Rupicapra pyrenaica) populations in the Pyrenees. The goal of this study was to analyze the post-outbreak BDV epidemiology in the first two areas affected by disease with the aim to establish if the infection has become endemic. We also investigated if BDV infected wild and domestic ruminants sharing habitat with chamois. Unexpectedly, we found different epidemiological scenarios in each population. Since the disease outbreaks, some chamois populations recuperated quickly, while others did not recover as expected. In chamois from the first areas, prevalence was high (73.47%) and constant throughout the whole study period and did not differ between chamois born before and after the BDV outbreak; in all, BDV was detected by RT-PCR in six chamois. In the other areas, prevalence was lower (52.79%) and decreased during the study period; as well, prevalence was significantly lower in chamois born after the disease outbreak. No BDV were detected in this population. A comparative virus neutralisation test performed with four BDV strains and one Bovine viral diarrhoea virus (BVDV) strain showed that all the chamois had BDV-specific antibodies. Pestivirus antibodies were detected in all the rest of analyzed species, with low prevalence values in wild ruminants and moderate values in domestic ruminants. No viruses were detected in these species. These results confirm the hypothesis that outbreaks of BDV infection only affect the Pyrenean chamois, although other wild ruminants can occasionally be infected. In conclusion, two different scenarios have appeared since the first border disease outbreaks in Pyrenean chamois: on the one hand frequent BDV circulation with possible negative impact on population dynamics in some areas and on the other, lack of virus circulation and quick recovery of the chamois population.

Seroprevalência de border disease em Pequenos ruminantes na região do Baixo Alentejo

A “Border Disease” é uma doença infecciosa causada por um pestivírus que afecta maioritariamente pequenos ruminantes, causando problemas reprodutivos, alterações congénitas e animais persistentemente infectados. Não existem registos da seroprevalência desta patologia em Portugal. O objectivo deste trabalho foi estudar a seroprevalência de “Border Disease” em explorações de pequenos ruminantes na região do Baixo Alentejo e relacioná-la com a raça dos animais, dimensão do efectivo, coabitação com bovinos e localização da exploração. Em 197 animais, observaram-se 10 seropositivos que correspondem a uma seroprevalência de 5%. Em 29 explorações observaram-se 6 positivas nas quais, havia pelo menos um animal seropositivo, que corresponde a 20,6 % das explorações. Não foi observada relação significativa da prevalência nas explorações com as raças dos animais, a dimensão do efectivo e a sua localização geográfica. Existe maior probabilidade de casos seropositivos de “Border Disease” em pequenos ruminantes que coabitem com bovinos. A seroprevalência de “Border Disease” é baixa na região do Baixo Alentejo. Mais estudos devem ser efectuados de forma a identificar a estirpe do vírus “Border Disease” (BDV) presente nesta região, a verificar se a seroconversão poderá ter origem no contacto com o vírus da diarreia viral bovina (BVDV) e estudar o impacto desta doença na produção de pequenos ruminantes no Baixo Alentejo.

"Self" and "nonself" manipulation of interferon defense during persistent infection: bovine viral diarrhea virus resists alpha/beta interferon without blocking antiviral activity against unrelated viruses replicating in its host cells

Bovine viral diarrhea virus (BVDV), together with Classical swine fever virus (CSFV) and Border disease virus (BDV) of sheep, belongs to the genus Pestivirus of the Flaviviridae. BVDV is either cytopathic (cp) or noncytopathic (ncp), as defined by its effect on cultured cells. Infection of pregnant animals with the ncp biotype may lead to the birth of persistently infected calves that are immunotolerant to the infecting viral strain. In addition to evading the adaptive immune system, BVDV evades key mechanisms of innate immunity. Previously, we showed that ncp BVDV inhibits the induction of apoptosis and alpha/beta interferon (IFN-alpha/beta) synthesis by double-stranded RNA (dsRNA). Here, we report that (i) both ncp and cp BVDV block the induction by dsRNA of the Mx protein (which can also be induced in the absence of IFN signaling); (ii) neither biotype blocks the activity of IFN; and (iii) once infection is established, BVDV is largely resistant to the activity of IFN-alpha/beta but (iv) does not interfere with the establishment of an antiviral state induced by IFN-alpha/beta against unrelated viruses. The results of our study suggest that, in persistent infection, BVDV is able to evade a central element of innate immunity directed against itself without generally compromising its activity against unrelated viruses ("nonself") that may replicate in cells infected with ncp BVDV. This highly selective "self" and "nonself" model of evasion of the interferon defense system may be a key element in the success of persistent infection in addition to immunotolerance initiated by the early time point of fetal infection.

Seroprevalence and characterization of pestivirus infections in small ruminants and new world camelids in Switzerland

The seroprevalence of pestivirus infections in small ruminants and new world camelids in Switzerland was determined. In 5'059 sera of sheep from 382 herds, 503 sera of goats from 54 herds and 109 sera of alpacas and lamas from 53 herds, population prevalences of 16.1% (sheep), 25.4% (goats) and 4.6% (new world camelids), respectively, were found. In order to determine the source of infection, the serological reactions were further characterized by cross-neutralization against two pestiviruses representing the genotypes BVDV (Bovine Virus Diarrhea Virus)-1 and BDV (Border Disease Virus)-1. Based on the ratio of respective antibody titres, 56.1% of the infections in sheep were induced by a BDV-1, 12.9% by a BVDV-1 and 31.0% by an unresolved pestivirus. In goats, the corresponding proportions were 23.4%, 10.2% and 66.4%, respectively. In Alpacas and Lamas, the source of infection of 1 animal was BDV-1 and that of 4 seropositive animals remained unresolved. In view of the phylogenetic relationship between pestiviruses, the unresolved source of infection is most probably attributable to other pestivirus genotypes circulating in small ruminants and new world camelids. Due to the predominance of pestiviral genotypes other than BVDV-1, the risk of transmission of BVDV from persistently infected small ruminants and new world camelids to cattle appears to be moderate, apart from close direct contact in mixed animal husbandry, communal pasturing and grazing in the Alps.

Infection of cattle with Border disease virus by sheep on communal alpine pastures

The purpose of this study was to investigate whether sheep grazing communal alpine pastures with cattle can transmit Border disease virus (BDV) to cattle. A total of 1170 sheep and 923 cattle were tested for BDV using RT-PCR (sheep) and for pestivirus antibodies using an ELISA (cattle), respectively, before being moved to one of 4 pastures (A, B, C and D). Eight sheep from pasture C were viraemic. 396 of 923 cattle examined before the pasture season were seronegative. The latter were re-examined after the pasture season and 99 were seropositive or indeterminate. Antibody specificity was determined in 25 of these using a serum neutralization test (SNT). BDV infection was confirmed in 10 cattle and was considered likely in 8 others. BVDV infection was confirmed in 4 cattle and considered likely in 3 after pasturing. The study has shown that the transmission of BDV from sheep to cattle is possible on communal alpine pastures.

Investigation of border disease and bovine virus diarrhoea in sheep from 76 mixed cattle and sheep farms in eastern Switzerland

The purpose of this study was to examine the occurrence of sheep persistently infected with Border disease virus (BDV) on 76 mixed cattle and sheep farms and whether seroconversion to BDV infection occurred in cattle of these farms. Seroprevalence of BDV and bovine viral disease virus (BVDV) infection in sheep was also investigated. Quantitative RT-PCR for pestivirus detection and an ELISA to detect pestivirus antibodies were used in 2'384 and 2'291 ovine blood samples, respectively. Another 27 seropositive sheep from ten flocks underwent serum neutralization testing to differentiate between BDV and BVDV antibodies. A BDV titre that was at least four times higher than the BVDV titre was interpreted as the result of BDV infection. Titres against BVDV were interpreted in an analogous fashion. All examined sheep were pestivirus-negative, 310 sheep were seropositive, 119 had an indeterminate titre and 1'862 were seronegative. The flock seroprevalence ranged from 0.0 to 73.9 %. Three of the 27 flocks that underwent serum neutralization testing were interpreted as BDV-infected because of 6 sheep with higher BDV titres, and 6 flocks were interpreted as BVDV-infected because of 14 sheep with higher BVDV titres.

Transmission of border disease virus from a persistently infected calf to seronegative heifers in early pregnancy

BACKGROUND: This study describes the transmission of border disease virus (BDV) from a persistently infected calf to seronegative heifers in early pregnancy, resulting in persistently infected fetuses. On day 50 of pregnancy (= day 0 of the infection phase), six heifers were co-housed in a free stall with a bull calf persistently infected with BDV (pi BVD) for 60 days. The heifers underwent daily clinical examination, and blood samples were collected regularly for detection of pestiviral RNA and anti-pestivirus antibodies. After day 60 (= day 110 of pregnancy), the heifers were slaughtered, and the fetuses and placentae underwent post-mortem and immunohistochemical examination and RT-PCR for viral RNA detection. RESULTS: Three heifers had mild viraemia from day 8 to day 14, and by day 40 all heifers had pestivirus antibodies identified as anti-BDV antibodies in the serum neutralisation test. The placenta of the three viraemic heifers had histological evidence of inflammation, and fetal organs from these heifers were positive for pestivirus antigen by immunohistochemical examination and for BD viral RNA by RT-PCR and sequencing. Thus, co-housing of heifers in early pregnancy with a pi-BDV calf led to seroconversion in all heifers and persistent fetal infection in three. CONCLUSIONS: Considering that pi-BDV cattle can infect other cattle and lead to persistent infection of the fetus in pregnant cows, BDV should not be ignored in the context of the mandatory BVDV eradication and monitoring program. This strongly suggests that BDV should be taken into account in BVD eradication and control programs.

Generación y Gestión Optimizadas de la Base de Datos de un Visual para su Implementación en un Simulador de Formación

Los Sistemas de Información Geográfica están desarrollados para gestionar grandes volúmenes de datos, y disponen de numerosas funcionalidades orientadas a la captura, almacenamiento, edición, organización, procesado, análisis, o a la representación de información geográficamente referenciada. Por otro lado, los simuladores industriales para entrenamiento en tareas de conducción son aplicaciones en tiempo real que necesitan de un entorno virtual, ya sea geoespecífico, geogenérico, o combinación de ambos tipos, sobre el cual se ejecutarán los programas propios de la simulación. Este entorno, en última instancia, constituye un lugar geográfico, con sus características específicas geométricas, de aspecto, funcionales, topológicas, etc. Al conjunto de elementos que permiten la creación del entorno virtual de simulación dentro del cual se puede mover el usuario del simulador se denomina habitualmente Base de Datos del Visual (BDV). La idea principal del trabajo que se desarrolla aborda un tema del máximo interés en el campo de los simuladores industriales de formación, como es el problema que presenta el análisis, la estructuración, y la descripción de los entornos virtuales a emplear en los grandes simuladores de conducción. En este artículo se propone una metodología de trabajo en la que se aprovechan las capacidades y ventajas de los Sistemas de Información Geográfica para organizar, optimizar y gestionar la base de datos visual del simulador, y para mejorar la calidad y el rendimiento del simulador en general. ABSTRACT Geographic Information Systems are developed to handle enormous volumes of data and are equipped with numerous functionalities intended to capture, store, edit, organise, process and analyse or represent the geographically referenced information. On the other hand, industrial simulators for driver training are real-time applications that require a virtual environment, either geospecific, geogeneric or a combination of the two, over which the simulation programs will be run. In the final instance, this environment constitutes a geographic location with its specific characteristics of geometry, appearance, functionality, topography, etc. The set of elements that enables the virtual simulation environment to be created and in which the simulator user can move, is usually called the Visual Database (VDB). The main idea behind the work being developed approaches a topic that is of major interest in the field of industrial training simulators, which is the problem of analysing, structuring and describing the virtual environments to be used in large driving simulators. This paper sets out a methodology that uses the capabilities and benefits of Geographic Information Systems for organising, optimising and managing the visual Database of the simulator and for generally enhancing the quality and performance of the simulator.

Intrinsic responses to Borna disease virus infection of the central nervous system

Immune cells invading the central nervous system (CNS) in response to Borna disease virus (BDV) antigens are central to the pathogenesis of Borna disease (BD). We speculate that the response of the resident cells of the brain to infection may be involved in the sensitization and recruitment of these inflammatory cells. To separate the responses of resident cells from those of cells infiltrating from the periphery, we used dexamethasone to inhibit inflammatory reactions in BD. Treatment with dexamethasone prevented the development of clinical signs of BD, and the brains of treated animals showed no neuropathological lesions and a virtual absence of markers of inflammation, cell infiltration, or activation normally seen in the CNS of BDV-infected rats. In contrast, treatment with dexamethasone exacerbated the expression of BDV RNA, which was paralleled by a similarly elevated expression of mRNAs for egr-1, c-fos, and c-jun. Furthermore, dexamethasone failed to inhibit the increase in expression of mRNAs for tumor necrosis factor α, macrophage inflammatory protein 1β, interleukin 6, and mob-1, which occurs in the CNS of animals infected with BDV. Our findings suggest that these genes, encoding transcription factors, chemokines, and proinflammatory cytokines, might be directly activated in CNS resident cells by BDV. This result supports the hypothesis that the initial phase of the inflammatory response to BDV infection in the brain may be dependent upon virus-induced activation of CNS resident cells.