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     

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 immune response to viral antigens as a determinant of arthritis in caprine arthritis-encephalitis virus infection

Evidence is reviewed which indicates that CAEV persists in infected goats with variable and restricted expression. Immunosuppression prevents the lesions caused by CAEV. Arthritis is enhanced in CAEV-challenged goats that have been immunized with inactivated CAEV or are persistently infected with CAEV. A large part of the synovial fluid immunoglobulin is antibody against virion surface glycoproteins. These observations support the hypothesis that the immune response to viral antigens is a major determinant of CAEV arthritis.     

Caprine enzootic arthritis-encephalitis in France: epidemiological and experimental studies

In an epidemiological study on CAEV-induced caprine arthritis, the ELISA carried out on mixed sera appeared to be an efficient pointer to viral articular pathology in flocks; the breed and origin of goats, the selection of flocks with high milk production proved to be factors which favour viral arthritis, the serological diagnosis of which remains a flock diagnosis. In addition, in an experimental infection, only one type II caprine strain induced significant cases of arthritis; the disease could be reproduced more effectively by the intra-articular route than intravenously. Lastly, in a vaccination test followed by infectious CAEV challenge, two vaccinated goats showed more severe arthritis than did non vaccinated control goats. These observations emphasise the importance of the different viral strains, of the penetration route of the virus, of the repetition of infections and of the immune response in the induction of CAEV arthritis.     

Antemortem Diagnosis of CDV Infection by RT-PCR in Distemper Dogs with Neurological Deficits without the Typical Clinical Presentation

In dogs with neurological disturbances without myoclonus and extraneural signs, the clinical diagnosis of distemper is difficult perform. Considering the great infectious potential of the disease, the possibility of carrying out an antemortem diagnosis of distemper is important, particularly in hospitalized patients with neurological disease. The present study was carried out to evaluate RT-PCR for antemortem CDV detection in hospitalized dogs with neurological disturbances without the typical findings of distemper. We investigated five dogs with canine distemper virus (CDV) encephalomyelitis, in which the clinical diagnosis was not performed owing to the absence of characteristic signs of the disease, such as myoclonus and systemic signs. We observed an apparent high sensitivity of RT-PCR in urine samples for detection of CDV: four out of five urine samples were RT-PCR positive. The results of the present study suggest that urine is a good biological sample for antemortem CDV detection by RT-PCR in dogs with distemper encephalomyelitis in which the clinical diagnosis is likely to be difficult owing to the absence of suggestive distemper signs. The use of two different body fluids (urine and CSF) may increase the RT-PCR sensitivity for antemortem diagnosis of distemper in such cases.     

Acute arthritis in caprine arthritis-encephalitis virus challenge exposure of vaccinated or persistently infected goats

Goats vaccinated with inactivated caprine arthritis-encephalitis virus (CAEV) developed more severe arthritis after infectious CAEV challenge exposure than did goats vaccinated with tissue culture medium. Arthritis also developed more rapidly in the group vaccinated with inactivated virus. In another experiment, goats with persistent CAEV infection developed acute arthritis after at least 2 injections of infectious CAEV at monthly intervals. In this experiment, the control group consisted of goats with persistent CAEV that were given tissue culture medium. Seemingly, the immune response to CAEV is an important cause of the CAEV-induced arthritis.     

Goat uterine epithelial cells are susceptible to infection with Caprine Arthritis Encephalitis Virus (CAEV) in vivo

ABSTRACT: The aim of this study was to determine, using immunofluorescence and in situ hybridization, whether CAEV is capable of infecting goat uterine epithelial cells in vivo. Five CAEV seropositive goats confirmed as infected using double nested polymerase chain reaction (dnPCR) on leucocytes and on vaginal secretions were used as CAEV positive goats. Five CAEV-free goats were used as controls. Samples from the uterine horn were prepared for dnPCR, in situ hybridization, and immunofluorescence. The results from dnPCR confirmed the presence of CAEV proviral DNA in the uterine horn samples of infected goats whereas no CAEV proviral DNA was detected in samples taken from the uninfected control goats. The in situ hybridization probe was complementary to part of the CAEV gag gene and confirmed the presence of CAEV nucleic acids in uterine samples. The positively staining cells were seen concentrated in the mucosa of the lamina propria of uterine sections. Finally, laser confocal analysis of double p28/cytokeratin immunolabelled transverse sections of CAEV infected goat uterus, demonstrated that the virus was localized in glandular and epithelial cells. This study clearly demonstrates that goat uterine epithelial cells are susceptible to CAEV infection in vivo. This finding could help to further our understanding of the epidemiology of CAEV, and in particular the possibility of vertical transmission.     

Serologic prevalence of caprine arthritis-encephalitis virus in California goat dairies

Fifty-three percent of goats in 13 California goat dairies had antibodies to caprine arthritis-encephalitis virus (CAEV), as determined by agar-gel immunodiffusion. Those goat dairies that reared kids on pasteurized milk had a lower seroprevalence than those that did not. Age, rearing kids on unpasteurized milk, and the presence of large joints were associated with antibodies to CAEV. Breed was associated with seroreactivity, but the association was confounded by other factors. Sex was not associated with antibodies to CAEV. The relationship between age and antibodies to CAEV was observed for goats reared on pasteurized or unpasteurized milk, which indicated that continued horizontal (contact) transmission may be important on these dairies and limited the effect of a pasteurized rearing program on control of CAEV infection.     

Caprine retrovirus infection in New South Wales: virus isolations, clinical and histopathological findings and prevalence of antibody

Caprine arthritis-encephalitis virus (CAEV) was isolated by explant cultures of carpal synovial membranes and lung from 7 goats in New South Wales. These goats were clinically affected with the arthritic, neurologic, and pneumonic forms of CAEV infection either singly or in combination. CAEV antibody was detected by the gel immunodiffusion precipitin (GDP) test in 5 of the 7 goats. Serum samples from 2,708 goats, from 115 herds, were examined for CAEV antibody using the GDP test. Approximately one-third of the animals and 82% of the herds tested had CAEV antibody. The infection was common in all breeds of dairy goats with an indication of a significantly lower prevalence in the Saanen breed (24.4%) compared to Nubians, British Alpines and Toggenbergs (43.8%, 38.7% and 39.1% respectively). CAEV antibody was also demonstrated in 11 of 230 Angora goats. The infection was equally common in all age groups, with slightly higher prevalence in males (83 of 230, 36%) compared to females (648 of 2,232, 29%). Among seropositive animals 85% were clinically normal. Of 280 clinically affected goats tested only 42% had detectable antibody. One of 5 sheep that had been in contact with infected goats in one herd had CAEV serum antibody.     

Phage display identifies two Caprine Arthritis Encephalitis Virus env epitopes

ABSTRACT: Using phage display and IgG of a goat infected with Caprine Arthritis Encephalitis Virus (CAEV) we obtained families of 7 mer constrained peptides with consensus motifs LxSDPF/Y and SWN/KHWSY and mapped the epitopes mimicked by them at the Env 6-LISDPY-11 and 67-WNTYHW-72 sites of the mature gp135 amino acid sequence. The first epitope fell into the N-terminal immunogenic aa1-EDYTLISDPYGFS- aa14 site identified previously with a synthetic peptide approach; the second epitope has not been described previously. The first epitope is mostly conserved across CAEV isolates whereas the second newly described epitope is extremely conserved in Small Ruminant Lentiviruses env sequences. As being immunodominant, the epitopes are candidate targets for mimotope-mediated diagnosis and/or neutralization.     

绵羊进行性肺炎病毒与山羊关节炎一脑炎病毒的血清学交叉反应的研究

本实验用琼脂凝胶免疫扩散试验（ＡＧＩＤＴ）和免疫印迹试验（ＩＢＡ）对实验感染绵羊进行性肺炎病毒（ＯＰＰＶ）的山羊血清与山羊关节炎—脑炎病毒（ＣＡＥＶ）抗原以及实验感染ＣＡＥＶ的绵羊血清与ＯＰＰＶ抗原的交叉反应进行了研究。４只接种ＯＰＰＶ的山羊中有一只山羊的血清可与ＣＡＥＶ琼扩抗原发生交叉反应,并在免疫印迹试验中可识别ＣＡＥＶ的ｇｐ４４、ｐ３５和ｐ２８。２只接种ＣＡＥＶ的绵羊中有一只绵羊的血清可与ＯＰＰＶ琼扩抗原发生交叉反应,并在免疫印迹试验中可识别ＯＰＰＶ的ｇｐ４４和ｐ２８。以上的交叉反应结果表明ＯＰＰＶ与ＣＡＥＶ的抗原之间具有密切的相关性,这对于ＯＰＰＶ通过山羊和ＣＡＥＶ通过绵羊的传代研究是非常重要的,并对将来的免疫预防策略具有重要的指导意义。     

Experimental infection of Mouflon-domestic sheep hybrids with caprine arthritis-encephalitis virus

OBJECTIVE: To determine whether monocyte-derived macrophages from Mouflon-domestic sheep hybrids (Ovis musimon X Ovis spp) were susceptible to productive infection with caprine arthritis-encephalitis virus (CAEV) in vitro and whether experimental inoculation of Mouflon-domestic sheep hybrids with a molecularly cloned CAEV would result in persistent infection. ANIMALS: 5 Mouflon hybrids. PROCEDURE: Macrophage monolayers were inoculated with virus in vitro. Three animals were inoculated with virus intratracheally. RESULTS: Productive replication of CAEV was demonstrated in monocyte-derived macrophages following in vitro and in vivo inoculation. Titer of infectious cytopathic CAEV produced by macrophages from the Mouflon hybrids was similar to titers produced by macrophages from an infected goat or by synovial membrane cells. Isolation of virus from monocyte-derived macrophages and use of a semiquantitative polymerase chain reaction assay to amplify a portion of the viral genome demonstrated persistent virus replication in all 3 inoculated animals. Two weeks after inoculation of sheep, approximately 1 of 5,000 monocytes was harboring the virus. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that Mouflon-domestic sheep hybrids are susceptible to infection with isolates of CAEV that cause infection in domestic small ruminants.     

Nematode eggs observed in cytology of cerebrospinal fluid diagnostic for intramedullary Spirocerca lupi spinal cord migration

Spinal spirocercosis due to aberrant Spirocerca lupi nematode migration is an emerging etiology for acute myelitis in dogs in Israel, causing severe, mostly nonsymmetrical hind limb paresis or paralysis, and sometimes tetraparesis or tetraparalysis. So far, incidental identification of parasites during spinal surgery or at necropsy provides the only definite diagnosis, while antemortem diagnosis of this condition has been uncertain. Specifically, antemortem diagnosis is based on the typical clinical presentation of acute, progressive, asymmetrical hind limb paresis or paralysis, with moderate to severe eosinophilic to mixed cerebrospinal fluid (CSF) pleocytosis and increased CSF protein concentration. Exclusion of other differential diagnoses also requires using spinal cord imaging. In this novel report, we document a case of an intradural spinal spirocercosis in a dog, diagnosed antemortem, by detecting S lupi eggs in the CSF, and subsequent treatment, resulting in the resolution of the clinical signs.     

Prevalence, spread and control of caprine arthritis-encephalitis virus in dairy goat herds in New South Wales

SUMMARY A study of the prevalence, spread and control of caprine arthritis-encephalitis virus (CAEV) in dairy goat herds in New South Wales (NSW) during 1986–1988 found that 56.8% of 1484 goats in 14 dairy herds were infected with CAEV. The prevalence of CAEV infection within most herds not implementing control measures increased during the study. At the end of the study, 59.7% of 1322 goats were infected. The prevalence of CAEV increased with age. Differences between breeds were less apparent. Within seven herds with a high standard of identification of goats, 149 of 812 goats seroconverted in an ELISA. Of these newly infected goats, 142 (95.3%) were > 1 yr of age and 96 (64.4%) were > 2 yr suggesting lateral spread of the virus. Most of the goats > 2 yr of age had been in the milking herd for a minimum of 3 to 6 months. The high seroconversion rate within the milking herd suggested that factors other than the ingestion of infected colostrum and milk before weaning were important for the spread of CAEV. Observations indicated that behaviour of goats, particularly reproductive behaviour among lactating does, and milking herd management practices are important in the spread of CAEV. A high density of livestock, poor livestock control and contamination of feed, water, equipment and personnel were implicated in transmission. Poorly functioning milking machines may also be involved. CAEV was eradicated from 3 herds by the implementation of strict control measures.     

Immunomodulation of caprine lentiviral infection by interleukin-16

Interleukin-16 (IL-16) is a proinflammatory cytokine produced by a variety of cells including lymphocytes, macrophages, mast cells, and eosinophils. We have shown in our previous studies increased expression of IL-16 mRNA and protein in caprine arthritis-encephalitis virus (CAEV)-infected goats blood. In this study, we determined the immunomodulatory effects of IL-16 in vitro using cells derived from CAEV infected and uninfected goats. Human recombinant IL-16 (rhIL-16) significantly increased chemotaxis of peripheral blood mononuclear cells (PBMCs) of both control and CAEV-infected goats. Pretreatment of PBMC with anti-goat CD4 monoclonal antibody inhibited IL-16-induced chemotaxis of PBMC of control and infected goats suggesting that IL-16 exerts its action in goats primarily by binding to CD4. The CAEV proviral DNA was less in caprine monocytes treated with rhIL-16 infected in vitro with CAEV. These data suggest inhibitory effect of IL-16 on viral integration. Flow cytometric studies indicated a trend toward IL-16-induced increased expression of lymphocyte activation markers. Combined with our previously reported data, these experiments suggest that increased IL-16 expression during CAEV infection may inhibit viral integration.     

Tuberculin skin testing in white-tailed deer (Odocoileus virginianus).

The comparative cervical skin test for antemortem diagnosis of tuberculosis was done 169 times on 116 different white-tailed deer of known Mycobacterium bovis infection status. The sensitivity and specificity were 97 and 81%, respectively. The magnitude of change in skin thickness at test sites was not significantly influenced by dosage of inoculum, dissemination of the disease process, or repeated skin testing. However, the magnitude of change in skin thickness was significantly greater in deer infected for less than 109 days than in deer infected for more than 109 days. As used in the present study, the comparative cervical skin test is a sensitive method of antemortem diagnosis of M. bovis infection in white-tailed deer.     

Risk factors associated with caprine arthritis-encephalitis virus infection in goats on California dairies.

Log-linear methodology was used to examine relations among caprine arthritis-encephalitis virus (CAEV) seroreactivity and host/management factors in a cross-sectional study of 2,826 goats on 13 California dairies. The CAEV serologic status was associated with age and feeding method (pasteurized/unpasteurized milk), but not with breed. Data from a prevalence survey of 321 goats from 2 additional dairies demonstrated very good fit of the selected log-linear model (P = 1.00), indicating that the model was very appropriate to describe the relations. Odds of seropositivity and odds ratios were generated by use of a logit model derived from the log-linear model. Goats raised by the unpasteurized feeding method were estimated to have been 3.3 times more likely to be CAEV-seropositive than goats fed by the pasteurized method, when adjusted for the effects of age. Goats aged 2, 3, 4, and 5 or greater years were estimated to have been 1.7, 2.6, 4.5, and 5.7 times, respectively, more likely to be CAEV-seropositive than were yearling goats when ratios were adjusted for pasteurization status. Breed, gender, and herd of origin were not associated with CAEV seroreactivity when the effects of other factors were considered. Estimated odds of CAEV seroreactivity and the associated odds ratios for combinations of factor levels are reported. In this study, the magnitude and direction of the associations among CAEV serologic status, age, and pasteurized feeding methods were demonstrated.     

Viral expression and leukocyte adhesion after in vitro infection of goat mammary gland cells with caprine arthritis-encephalitis virus

A characteristic lesion in goats infected by the lentivirus CAEV is mastitis with lymphoid hyperplasia. In order to investigate the mechanism of lesion formation, cultures highly enriched in microvascular endothelial cells, mature and immature luminal epithelial cells, fibroblasts and myoepithelial cells were established from goat mammary gland biopsies. Their susceptibility to in vitro infection with two distinct types of CAEV was investigated by PCR, antigen expression and cytopathy. The capacity of infected mammary gland cells to bind uninfected caprine leukocytes was determined by flow cytometry. All cell types tested were susceptible to CAEV infection in vitro, with different levels of sensitivity according to cell phenotype. Our results suggest that the limited extent of natural infection of mammary gland cells reflects a protective local immune response, and that the myoepithelial cell could act as a reservoir cell. After infection, the mature luminal cell acquires the capacity to bind leukocytes in vitro, which could indicate a facilitation of cellular interactions. The distinct reactions of the different cell types to CAEV infection may be correlated with events leading to progressive lesion development during the natural infection.     

Magnetic resonance imaging of syringomyelia in five dogs

This report describes the use of magnetic resonance imaging (MRI) in five dogs to diagnose spontaneous syringomyelia. Four of the dogs had cervical syringomyelia associated with hydrocephalus, and one of these cases was analogous to the Dandy-Walker syndrome in humans. The fifth dog had thoracic syringomyelia without hydrocephalus. It was possible to diagnose the condition antemortem in all of the dogs by MRI. It is suggested that MRI is a straightforward and effective tool for the antemortem diagnosis of syringomyelia in dogs.     

Ultrasonographic Appearance of Dandy Walker-Like Syndrome in a Boston Terrier

Congenital cerebellar disorders can be caused by in utero or neonatal infections, genetic aberrations causing malformations, and neurodegenerative processes. Most congenital cerebellar disorders are diagnosed definitively with histopathology. However, antemortem diagnosis of cerebellar malformations can be made by imaging the brain. This paper describes the antemortem appearance of a congenital cerebellar malformation in a Boston Terrier puppy on ultrasound images. This appearance was compared with the postmortem findings that were comparable to Dandy Walker Syndrome in humans. A previous report of this syndrome in Boston Terriers suggests the problem may be inherited in this breed.