Activation of small ruminant aortic endothelial cells after in vitro infection by caprine arthritis encephalitis virus

Small ruminants infected by the lentiviruses caprine arthritis-encephalitis virus (CAEV), originally isolated from a goat, or maedi-visna virus, originally from sheep, typically develop an organising lymphoid infiltration of affected tissues. This could reflect modulation of the migration pattern of lymphocytes in infected animals. Possible active contribution by vascular endothelial cells was investigated using an in vitro model. Low-passage cultured ovine aortic endothelium proved susceptible to productive infection by CAEV without significant cytotoxicity. Infected endothelial cells maintained expression of endothelial markers, increased MHC class I antigen expression and initiated expression of the adhesion molecule VCAM -1 and, at a late stage, MHC class II antigens. Infected endothelial cells showed a two-fold increase in binding capacity for sheep peripheral blood leucocytes over uninfected controls. Such events could contribute to the tissue distribution of lymphoid cells and local immune responses in lentiviral infections of small ruminants.     

山羊关节炎-脑炎研究进展

山羊关节炎-脑炎(Caprine arthritis encephalitis，CAE)是由反转录病毒科慢病毒属山羊关节炎脑炎病毒(CAEV)引起的山羊的慢性传染病。临床症状以山羊羔脑脊髓炎和成年山羊多发性关节炎、硬结性乳房炎以及间质性肺炎为特征。在未认识该病之前，对其说法不一。1964年Stunzi在瑞士称其为山羊慢性淋巴细胞性多发性关节炎；1969年Starrou在德国发现，称其为山羊肉芽肿性脑脊髓炎；1974年Cark等在美国报道为山羊病毒性白质脑脊髓炎。     

An epidemic of caprine arthritis encephalitis in Japan: isolation of the virus

A disease characterized by arthritis of carpal joints and occasionally by pneumonia was seen among goats on a farm in Nagano prefecture of Japan in the summer of 2002. Serological investigation was done on 30 goats, that is one group on the farm by agar gel immunodiffusion tests using maedi-visna virus as the antigen, and 19 goats were positive. The caprine arthritis encephalitis virus genome was detected in peripheral blood leukocytes from several antibody-positive goats. Two goats among them were necropsied and used for pathological tests and virus isolation. The isolated virus was serially propagated in fetal lamb lung cell cultures. Goats inoculated with the culture fluid became antibody positive. These results suggested that a CAEV-infected goat had been introduced accidentally to the farm and that subclinical infection occurred among the flock.     

Isolation of caprine arthritis encephalitis virus from goats in Mexico.

A lentivirus was isolated from 2 goats in Mexico that were seropositive to caprine arthritis encephalitis virus (CAEV) by the agar gel immunodiffusion (AGID) test. The lentivirus was identified as CAEV by the observation of giant multinucleated cells (syncytia) in goat synovial membrane (GSM) monolayers co-cultivated with blood mononuclear (BMN) cells from the seropositive goats, and by amplifying a DNA segment of the CAEV gag gene using the polymerase chain reaction (PCR) technique. Subsequently, cell supernatants from the GSM cells co-cultivated with BMN cells were used to infect 2 CAEV-seronegative goats. These goats seroconverted to CAEV as determined by the AGID test, and CAEV was re-isolated from these goats. One of the goats developed polyarthritis 8 mo after inoculation. Previous serological surveys indicate that infection with CAEV is prevalent among goats in Mexico. To our knowledge this is the first report of CAEV isolation in Mexico. Because of globalization of markets and increased trading among nations, the rapid identification and reporting of diseases such as CAEV are important to prevent the dissemination of these diseases.     

The effect of caprine arthritis encephalitis virus infection on production in goats

Three consecutive years of monitoring 248 goats in the same flock, found that the first lactation milk yield was significantly higher in seronegative (578 L) than in seropositive (447 L) animals but this difference disappeared in the subsequent second to fourth lactations. No significant differences were found in the proportions of seronegative and seropositive does in the flock, the percentage of animals culled, the number of offspring, or in the number of cases of udder bacterial infection, irrespective of age.Removal of kids from their dams before suckling and the feeding of pasteurised colostrum resulted in reduced numbers of seropositive animals. Nevertheless, by approximately 24 months of age, 76.9% of these initially seronegative animals were seropositive, a factor that significantly contributed to flock seropositivity. This finding could be attributed to lateral virus transmission from seropositive to seronegative kids because of lack of segregation within the flock.     

Transmission of small ruminant lentiviruses

Small ruminant lentiviruses (SRLV) are classical slow retroviruses causing chronic inflammatory disease in a variety of target organs. The routes of transmission have been investigated and a large body of evidence has accumulated over many years. The main routes are through ingestion of infected colostrum and/or milk, or through inhalation of respiratory secretions. However, many studies also provide evidence that intrauterine infection may occur, though the extent and significance of this route is controversial. Embryos treated to IETS standards appear to pose very little risk of infection. SRLV have been detected in semen suggesting a potential source of transmission. However, such transmission has not been demonstrated to date. The application of control measures based on this information allows more efficient strategies to be developed which will reduce the rate of transmission.     

Presence of virus particles in neural cells of goats with caprine arthritis encephalitis

The possible neurotropism of ungulate lentivirus was examined in clinical cases. Brain and ganglion tissue samples were examined from six female goats with caprine arthritis encephalitis and from six healthy controls. Ultrastructural examination revealed typical cytoplasmic A type retrovirus particles in the neural tissue of the diseased does. None were seen in the respective controls. Furthermore, no budding or extracellular retrovirus particles were seen in any of the neural tissue samples examined.     

山羊关节炎-脑炎的研究现状

山羊关节炎-脑炎(Caprine Arthritis-Encephalitis,CAE)是由山羊关节炎-脑炎病毒(Caprine Arthritis-Enceephalitis Virus,CAEV)引起的一组临床病症.临床出现以慢性持续性病症为特征的羔羊的急性脑脊髓炎,成年羊的关节炎、乳腺炎、慢性进行性肺炎和脑炎等[1].     

实验感染山羊关节炎—脑炎病毒的绵羊抗体应答反应的研究

本实验用琼脂凝胶免疫扩散试验和免疫印迹试验对实验感染山羊关节炎—脑炎病毒（ＣＡＥＶ）的绵羊抗体应答反应进行了研究，用两种方法都可在接毒绵羊的血清中检测到ＣＡＥＶ的抗体。琼脂凝胶免疫扩散试验最早可于接毒后的第７周时检测到抗体，免疫印迹试验最早可于接毒后的第６周时检测到抗ＣＡＥＶ的ｇｐ１２５、ｇｐ４４、ｐ３５、ｐ２８和ｐ１４的抗体，这说明免疫印迹试验更为敏感一些。本实验的结果表明ＣＡＥＶ可在绵羊体内诱生明显的体液免疫应答反应，因此用ＣＡＥＶ通过绵羊体传代的方法可能会得到具有良好的抗原性的ＣＡＥＶ毒株，这对于人工培养ＣＡＥＶ强毒是非常重要的。此外，本实验还为ＣＡＥＶ通过绵羊体传代的研究提供了非常实用的检测手段     

Prevention strategies against small ruminant lentiviruses: an update

Small ruminant lentiviruses (SRLVs), including maedi-visna virus (MVV) of sheep and caprine arthritis-encephalitis virus (CAEV), are widespread, cause fatal diseases and are responsible for major production losses in sheep and goats. Seventy years after the legendary maedi-visna sheep epidemic in Iceland, which led to the first isolation of a SRLV and subsequent eradication of the infection, no vaccine or treatment against infection has been fully successful. Research during the last two decades has produced sensitive diagnostic tools, leading to a variety of approaches to control infection. The underlying difficulty is to select the strategies applicable to different epidemiological conditions. This review updates the knowledge on diagnosis, risk of infection, immunisation approaches and criteria for selecting the different strategies to control the spread of SRLVs.     

Small ruminant lentiviruses in Jordan: evaluation of sheep and goat serological response using recombinant and peptide antigens

Small ruminant lentiviruses infect sheep and goats worldwide, causing chronic progressive diseases and relevant economic losses. Disease eradication and prevention is mostly based on serological testing. The goal of this research was to investigate the presence of the small ruminant lentiviruses (SRLVs) in Jordan and to characterize the serological response in sheep and goat populations. A panel of sera were collected from flocks located in Northern Jordan and Jordan Valley. The samples were tested using three ELISA assays: a commercially available ELISA based on p25 recombinant protein and transmembrane peptide derived from British maedi–visna virus (MVV) EV1 strain, an ELISA based on P16-P25 recombinant protein derived from two Italian strains representative of MVV- and caprine arthritis encephalitis virus (CAEV)-like SRLVs, and an ELISA based on SU5 peptide from the same two Italian isolates. The results indicate that both MVV- and CAEV-like strains are present in Jordan and that the majority of the viruses circulating among sheep and goat populations belong to the MVV-like genotype.     

Enzootic ataxia and caprine arthritis/encephalitis virus infection in a New England goat herd [corrected

Ataxia was diagnosed in kids from a New England goat herd. Concurrent infection with the caprine arthritis/encephalitis (CAE) virus contributed to the development of hind limb ataxia and weakness in one of the kids. Six kids from this herd had signs of hind limb ataxia and paralysis. Detailed evaluation of 2 of the affected kids revealed low liver and serum copper concentrations and spinal cord demyelination. One kid also had histologic changes in the CNS and lungs, compatible with a diagnosis of CAE. Serum copper concentration was determined in affected goat kids and their dams and was compared with serum copper concentration in clinically normal kids and their dams from the same herd. Serum copper concentration also was measured in dams and kids in a control herd that had no history of ataxia. The mean serum copper concentration in affected kids was 0.125 microgram/ml, compared with 0.45 microgram/ml in unaffected kid herdmates. Kids from the control herd had mean serum copper concentration of 0.6 microgram/ml. Mean serum copper concentration in dams of kids with neurologic signs also was low (0.25 microgram/ml), compared with that (0.5 microgram/ml) in dams of clinically normal kids of the affected herd and that (0.95 microgram/ml) in dams of kids of the control herd. Results of a serologic survey (by use of agar gel immunodiffusion) of the affected herd for CAE indicated that 69.5% of the goats were seropositive. Dietary copper intake was determined to be adequate in this goat herd; therefore, copper deficiency appeared to be conditioned by an interfering substance. However, a search for interfering substances was unrewarding.     

The gp135 of caprine arthritis encephalitis virus affords greater sensitivity than the p28 in immunodiffusion serology

The 135,000 mw glycoprotein (gp135) and the 28,000 mw internal protein (p28) of caprine arthritis encephalitis virus are major viral constituents in precipitin lines formed between crude antigen preparations and sera from infected goats. In testing 307 goat and sheep sera, 118 samples were positive in a gp135 assay and only 82 were positive in a p28 assay. However, some goat sera were found which reacted only with the p28 and therefore testing for antibody against both proteins may be necessary to identify a maximum number of virus infected goats by immunodiffusion.     

Phylogenetic analysis of small ruminant lentiviruses detected in Slovenia

Small ruminant lentiviruses (SRLV), which belong to the Retroviridae family, infect goats and sheep worldwide. The aim of this study was to characterize the SRLV strains circulating in Slovenia, by phylogenetic analysis of two genomic regions, 1.8 kb gag-pol fragment and 1.2 kb pol fragment. The results of our study revealed that Slovenian SRLV strains are highly heterogeneous, with ovine strains belonging to genotype A and caprine strains to genotypes A and B. The closest relatives of sheep virus sequences from two flocks that clustered together (SLO 35, 36) were found to be in subtype A5. A cluster composed of four sheep virus sequences (SLO 31) was clearly divergent from all other subtypes in group A and could not be assigned to any of them. The virus sequences from one goat flock belonged solely to subtype B1, whereas virus sequences from more than one genotype were found to circulate within the other two goat flocks, belonging to subtype B1 (SLO 1 and SLO 37) and to genotype A (SLO 2 and 78–88 g). Two goat virus sequences (SLO 2) were found to belong to genotype A and could not be assigned to existing subtypes. One goat virus sequence (37–88 g) from flock 37 was clearly different from other sequences of this flock and was more closely related to genotype A sequences. We propose two new subtypes within genotype A, subtype A14 (SLO 2) and A15 (SLO 31).     

First partial characterisation of small ruminant lentiviruses from Greece

Small ruminant lentivirus (SRLV) infections are widespread in Greece, but SRLVs have never been isolated and characterized. In this study, we present the sequence of a 574-nucleotide (191-amino acid) region of the gag gene of SRLV strains from four sheep and one goat from a single geographic area of Greece. All five sequences appeared to be closely related at both nucleotide (2.1-14.2% variation) and deduced amino acid (1.6-4.2% variation) level. Greek SRLV strains were closer to ovine prototypic strains (average divergence 16.8%) than to the caprine strain CAEV-Co (21% divergence). By amino acid composition, the Greek SRLVs were on the average more than twice as distant from CAEV-Co as from other ovine strains. Phylogenetic analysis suggested that Greek strains segregate into a unique group, separate from, but related to, other ovine prototype sequences.     

Molecular epidemiology and pathogenesis of ruminant herpesviruses including bovine, buffalo and caprine herpesviruses 1 and bovine encephalitis herpesvirus

Restriction endonuclease DNA fingerprints of herpesviruses isolated from 3 unrelated epidemics of bovine encephalitis are similar to each other and totally different from bovine herpesvirus 1 (BHV1). Herpesviruses, antigenically related to BHV1, isolated from goats and buffalo have distinct DNA fingerprints. We propose that bovine encephalitis herpesvirus is prototypic of a new bovine herpesvirus type and that alpha herpes viruses from individual ruminant species are species specific.     

Relationships between infection with caprine arthritis encephalitis virus, intramammary bacterial infection and somatic cell counts in dairy goats.

Somatic cell counts, the bacteriological condition of the milk and antibodies against caprine arthritis encephalitis virus (CAEV) were measured monthly throughout lactation in 121 lactating goats of the Murcia-Granada breed in four commercial dairy goat herds. The prevalence of bacterial intramammary infection was 5.6 per cent and the prevalence of CAEV infection was 20.6 per cent. An analysis of variance revealed a significant effect of herd, intramammary infection and the interaction between intramammary infection and CAEV on the somatic cell count. In udder halves free of intramammary infection, the somatic cell counts were significantly lower in seronegative goats than in seropositive goats (P<0.05), but the difference was not significant in udder halves persistently infected by bacteria. There was a significant increase in somatic cell counts due to bacterial intramammary infection (P<0.01) in the seronegative goats, but this effect was not present in the seropositive animals.