Search Results (34)

Caprine arthritis and encephalitis (CAE), caused by small ruminant lentivirus (SRLV), is a key disease of goats, with chronic inflammation of joints and brain symptoms leading to losses in milk production and animal trade. In this study, we analyzed gene expressions in the milk somatic cells (MSCs) of seropositive (SRLV-SP) and seronegative (SRLV-SN) goats to identify transcriptomic changes using a non-invasive sampling method. Materials and Methods: This study was conducted on goats of two Polish breeds (Polish Improved White and Polish Improved Fawn), which were kept at the Institute of Genetics and Animal Biotechnology, Polish Academy of Sciences, during their first lactation. MSCs were isolated from milk, and gene expression was analyzed using the Goat Gene Expression Microarray. The results were verified by RT-qPCR for five genes (DUSP26, PRLR, SCARA3, APBB2, OR4F4). Statistical analysis was performed in GeneSpring 12 software. Results: Microarrays showed reduced expression of DUSP26, PRLR, SCARA3, APBB2, and OR4F4 genes in SRLV-SP goats. RT-qPCR confirmed changes for DUSP26, SCARA3, and APBB2. Functional analysis indicated associations with immune processes and HIV-like pathways. Discussion: The results suggest that SRLV induces transcriptomic perturbations, especially in immunity-related genes. MSCs are an effective model for non-invasive studies, and further studies may support strategies for combating CAE. Full article

In 2023, a molecular study was conducted on the Hungarian goat population to determine genotypes and subtypes of small ruminant lentiviruses (SRLV) infecting these herds. Ten goat herds seropositive for SRLV infection according to a serosurvey conducted earlier in Hungary were selected, and 135 adult goats (>1 year old) were blood sampled. The two-stage nested real-time PCR (nRT-PCR) was used to detect proviral DNA of SRLV and distinguish between two main viral genotypes (A and B). PCR products were submitted for Sanger dideoxy sequencing, and phylogenetic and molecular evolutionary analyses were conducted on the 200–250 bp-long proviral DNA sequences from the end of long terminal repeat (LTR) region and beginning of gag gene using the MEGA11 software. Reference strains included strains most identical to Hungarian sequences according to the Standard Nucleotide BLAST and prototypic strains for the relevant genotypes and subtypes. Proviral DNA of SRLV was detected in goats from all ten tested herds. A single SRLV genotype was detected in 6 herds—genotype A in three herds and B also in three herds. In four herds, mixed infection with genotypes A and B was confirmed. In total, 110/135 seropositive goats tested positive in the nRT-PCR (81.5%): 49/110 goats (44.5%) for genotype A, 54/110 goats (49.1%) for genotype B, and 7/110 goats (6.4%) for both genotypes. Hungarian sequences belonged to subtypes A1/A18, A2, and subtype B1. This is the first study which shows that Hungarian goats are infected by SRLV belonging to both genotypes A and B. Full article

Caprine arthritis encephalitis is an infectious disease caused by the caprine arthritis encephalitis virus that infects goats, sheep, and other small ruminants. An outbreak of CAEV could be extremely harmful to the goat farming industry and could cause severe economic losses. We designed specific primers and probes for the gag gene and established a TaqMan real-time quantitative polymerase chain reaction assay. This method’s correlation coefficient (R²) was >0.999, and the sensitivity of the assay to the plasmid-carried partial gag gene was approximately 10 copies/µL, 1000 times higher than that of conventional PCR. No specific fluorescence was detected for other sheep viruses. Using this method, we tested 776 asymptomatic sheep blood samples and 4 neurodegenerative sheep brain samples from six farms in eastern China, and the positivity rate was 0.77% (6/780). The gag gene was partially sequenced in the three positive samples and compared with the sequences from other representative strains in GenBank. The results revealed that all three strains belonged to the B1 subtype and were most closely related to the strains from Shanxi and Gansu, previously isolated in China, with their homology ranging from 97.7% to 98.9%. These results suggest that the designed RT-qPCR assay can be used to detect subclinical CAEV in sheep and that the virus is still present in eastern China. Full article

This article presents the results of virological and genetic studies of an isolate of caprine arthritis encephalitis (CAE) virus from the republic of Mordovia, Russian Federation. The isolate was found during monitoring studies of goat blood samples for the viral genome, and the presence of antibodies to lentiviruses was detected. According to the recommendation of the OIE, the positive result of PCR was confirmed with nucleotide sequencing. It was found that the obtained nucleotide sequence is identical to the genome of small ruminant lentiviruses presented in the GenBank database. Phylogenetic analysis showed that the isolate “Mordovia-2018” was included in the same cluster with an isolate from the Tver region of the Russian Federation detected in 2008. The sequence of the fragment of the env-gene of the isolate from the republic of Mordovia is available in GenBank under the number MN186380.1. To isolate the virus, a fraction of peripheral blood monocyte cells from the animal’s blood was added to a monolayer of lamb synovial membrane cell culture, and ten passages were carried out. The first manifestations of the cytopathic effect were observed after the third passage on the eighth day of cultivation in the form of single large cells of irregular shape with 5–7 nuclei. At the seventh passage, multiple syncytium with 7–12 nuclei were observed. At subsequent passage levels, the formation of syncytium containing more than 10–14 nuclei was observed. Full article

Jaagsiekte retrovirus (JSRV)-induced ovine pulmonary adenocarcinoma (OPA) is an important ovine respiratory disease in Switzerland. Furthermore, ovine lungs with OPA frequently exhibited lesions suggestive of maedi-visna virus (MVV) or caprine arthritis encephalitis virus (CAEV) infection, indicating that co-morbidities might occur. Lungs and pulmonary lymph nodes were sampled from suspected OPA cases, inflammatory lung lesions and control lungs (total of 110 cases). Tissues were (a) processed for histology and immunohistochemistry (IHC), and (b) underwent DNA extraction and real-time PCR for JSRV, MVV and CAEV. Peptide sequences were used to generate virus-specific customized polyclonal antibodies. PCR-positive OPA cases and formalin-fixed and paraffin-embedded MVV- and CAEV-infected synovial cell pellets served as positive controls. Fifty-two lungs were histologically diagnosed with OPA. Histological evidence of MVV/CAEV infection was detected in 25 lungs. JSRV was detected by PCR in 84% of the suspected OPA cases; six were co-infected with MVV and one with CAEV. MVV was detected by PCR in 14 cases, and four lungs were positive for CAEV. Three lungs had MVV/CAEV co-infection. In IHC, JSRV was detected in 91% of the PCR-positive cases, whereas MVV and CAEV immunoreactivity was seen in all PCR-positive lungs. Although PCR showed a higher sensitivity compared to IHC, the combined approach allows for investigations on viral cell tropism and pathogenic processes in co-morbidities, including their potential interdependency. Furthermore, an immunohistochemical tool for specific differentiation of MVV and/or CAEV infection was implemented. Full article

The retrovirus causing caprine arthritis encephalitis (CAE), a slowly progressive inflammatory disease in goats, belongs to the group of small ruminant lentiviruses (SRLVs) which cause lifelong infections that ought to be avoided for animal welfare as well as economic reasons. SRLV accreditation has been in place for forty years in The Netherlands and is based on the screening of small ruminant sera for specific antibodies. This paper evaluates 38 dairy goat herds that lost CAEV accreditation between 2012 and 2022. The characteristics of these herds are discussed, and specific follow-up scenarios, depending on desired goals, are introduced. The herd size of the participating herds varies from approximately 400 to 4600 adult dairy goats. The larger herds tended to be more prone to lose herd accreditation and had more difficulties regaining accreditation. Possible routes of introduction are lined up. The Royal GD’s tailor-made approach and advice to support livestock farmers with herds that have lost CAE accreditation are discussed in detail. Specific emphasis is placed on the strategic deployment of various diagnostic tests (such as antibody ELISAs and PCR) in different media, such as (pooled) sera, (bulk)milk and tissue samples. Special attention is paid to the added value of retrospective bulk milk testing or the specific testing of groups based on housing and management, which enables the investigation of the moment of viral introduction and route of transmission into a herd. Furthermore, the prospective implementation of bulk milk and strategic pooled milk sample testing in the Dutch SRLV accreditation programs intensifies surveillance and enables the taking of swift action to prevent further transmission within and between herds. An appeal is made to share experiences to improve programs collectively, and to start research into the underlying mechanisms. Full article

Animal lentiviruses (LVs) have been proven to have the capacity to cross the species barrier, to adapt in the new hosts, and to increase their pathogenesis, therefore leading to the emergence of threatening diseases. However, their potential for widespread diffusion is limited by restrictive cellular factors that block viral replication in the cells of many species. In previous studies, we demonstrated that the restriction of CAEV infection of sheep choroid plexus cells was due to aberrant post-translation cleavage of the CAEV Env gp170 precursor. Later, we showed that the lack of specific receptor(s) for caprine encephalitis arthritis virus (CAEV) on the surface of human cells was the only barrier to their infection. Here, we examined whether small ruminant (SR) cells can support the replication of primate LVs. Three sheep and goat cell lines were inoculated with cell-free HIV-1 and SIVmac viral stocks or transfected with infectious molecular clone DNAs of these viruses. The two recombinant lentiviral clones contained the green fluorescent protein (GFP) reporter sequence. Infection was detected by GFP expression in target cells, and the infectious virus produced and released in the culture medium of treated cells was detected using the indicator TZM-bl cell line. Pseudotyped HIV-GFP and SIV-GFP with vesicular stomatitis virus G glycoprotein (VSV-G) allowed the cell receptors to be overcome for virus entry to further evaluate the viral replication/restriction in SR cells. As expected, neither HIV nor SIV viruses infected any of the SR cells. In contrast, the transfection of plasmid DNAs of the infectious molecular clones of both viruses in SR cells produced high titers of infectious viruses for human indicators, but not SR cell lines. Surprisingly, SR cells inoculated with HIV-GFP/VSV-G, but not SIV-GFP/VSV-G, expressed the GFP and produced a virus that efficiently infected the human indictor, but not the SR cells. Collectively, these data provide a demonstration of the lack of replication of the SIVmac genome in SR cells, while, in contrast, there was no restriction on the replication of the IV-1 genome in these cells. However, because of the lack of functional receptors to SIVmac and HIV-1 at the surface of SR cells, there is specific lentiviral entry. Full article

Chronic interstitial pneumonia (CIP) is a main pathology of sheep infected with small ruminant lentivirus (SRLV). Caprine arthritis-encephalitis (CAE) is caused by the same pathogen; however, the presence of CIP has been only occasionally reported in SRLV-infected goats. We carried out a cross-sectional study to determine the prevalence of histopathological lesions indicative of CIP in goats with symptomatic CAE, and to investigate whether CIP was associated with a higher prevalence of other types of pneumonia (purulent bronchopneumonia, fibrinous pleuropneumonia) or bacterial infections. Lung specimens and bronchial swabs were collected for histopathological and bacteriological examination, respectively, from 116 goats from a CAE-affected herd. All goats were euthanized due to severe clinical signs of CAE. The goats were seropositive for SRLV infection in two different ELISAs and the presence of SRLV antigen in the lung tissue was confirmed by immunohistochemistry. Histopathologically, pneumonia of any type was confirmed in 82 goats (70.7%) and CIP was present in 67 goats (57.8%). In most goats, the severity of the histopathological features of pneumonia was mild. Bacteria were detected in bronchial swabs from 73 goats (62.9%). CIP proved to be significantly positively linked to the occurrence of purulent bronchopneumonia (p < 0.001), fibrinous pleuropneumonia (p = 0.001), and of the infection of lungs with bacteria capable of causing pneumonia (p = 0.050). The causal character of these associations should be considered and warrants further investigation. Full article

Small ruminant lentiviruses (SRLVs) belong to the genus Lentivirus in the Retroviridae family, which are responsible for the diseases maedi-visna and caprine arthritis-encephalitis in sheep and goats worldwide and are also widespread in Slovenian sheep and goats. SRLVs cause lifelong infections with chronic inflammatory lesions in various organ systems. Cross-species transmission of SRLV strains in sheep and goats is well documented, but there are few data on the ability of these viruses to infect wild ruminants. The objective of this study was to investigate whether SRLVs circulate among wild small ruminants in Slovenia. During the 2017–2018 hunting season, a total of 38 blood samples were collected from free-ranging chamois (Rupicapra rupicapra) and European mouflon (Ovis ammon musimon). The serum samples were tested for antibodies against SRLV by enzyme-linked immunosorbent assay (ELISA). The serological tests revealed that of all tested mouflons, 1 animal (11.1%) was seropositive, while all samples from chamois were negative. Based on the results of this study and considering the results of previous studies in which SRLV infections were detected in mouflons with low seroprevalence, it is very likely that the detected seropositive animal was an incidental spillover host for SRLV. Although no seropositive samples were found in chamois, we cannot speculate on whether chamois may not be a host for SRLV infection because of the small sample size and the disadvantages of the ELISA assay used when applied to samples from chamois. Full article

Caprine arthritis encephalitis (CAE) and caseous lymphadenitis (CLA) are two infectious diseases affecting goat welfare and production throughout the world. There are no current data regarding their prevalence in Sweden, and the aim of this pilot study was therefore to estimate the occurrence in Swedish milk-producing goats, but also to assess the agreement between milk and sera as sample material for diagnosis and to investigate the association between the somatic cell count (SCC) in bulk milk and the occurrence of CAE and CLA. Serum, individual milk, and bulk-tank milk samples were collected from 214 dairy goats in 10 herds. All samples were analysed by ELISA to detect antibodies for CAE and CLA, and 14.6% of the goats were seropositive for CAE, whereas 19.3% of the goats were seropositive for CLA. The agreement between individual milk and serum samples was over 90% for both diseases and individual milk samples can therefore be considered as an alternative material for analysis in a future eradication programme. Based on the limited number of samples, there was also a significant correlation between bulk-milk test results and within-herd seroprevalence for both CAE and CLA. The SCC in bulk-milk samples was measured using a DeLaval cell counter. The medium SCC was 639,000 cells/mL and no association between SCC and CAE or CLA could be found. The results indicate that CAE and CLA are two common diseases in Swedish goat herds, but further studies based on a larger number of herds are needed to draw conclusions about the national prevalence. The results also indicate that milk can be used as a more cost-effective sampling media for diagnosing CAE and CLA compared to serology, which is the standard procedure today. Hopefully, the results can support the establishment of a successful programme to control the diseases, with the ambition to eradicate CAE and CLA in Sweden. Full article

Small ruminant lentiviruses (SRLVs), i.e., CAEV and MVV, cause insidious infections with life-long persistence and a slowly progressive disease, impairing both animal welfare and productivity in affected herds. The complex diagnosis of SRLVs currently combines serological methods including whole-virus and peptide-based ELISAs and Immunoblot. To improve the current diagnostic protocol, we analyzed 290 sera of animals originating from different European countries in parallel with three commercial screening ELISAs, Immunoblot as a confirmatory assay and five SU5 peptide ELISAs for genotype differentiation. A newly developed nested real-time PCR was carried out for the detection and genotype differentiation of the virus. Using a heat-map display of the combined results, the drawbacks of the current techniques were graphically visualized and quantified. The immunoblot and the SU5-ELISAs exhibited either unsatisfactory sensitivity or insufficient reliability in the differentiation of the causative viral genotype, respectively. The new truth standard was the concordance of the results of two out of three screening ELISAs and the PCR results for serologically false negative samples along with genotype differentiation. Whole-virus antigen-based ELISA showed the highest sensitivity (92.2%) and specificity (98.9%) among the screening tests, whereas PCR exhibited a sensitivity of 75%. Full article

South Tyrol has implemented, in 2007, a mandatory eradication program against Caprine Arthritis Encephalitis Virus (CAEV), a virus known to cause economic losses related to decreases in milk production and milk quality in goats, along with poor animal welfare and premature death. After a great initial decrease in the seroprevalence, the program has reached a tailing phase with scattered positivities. Potential risk factors associated with the multispecies farming system, a traditional approach in South Tyrol, are evaluated in this study, in order to better understand some of the potential causes leading to the tailing phenomenon. A statistically significant number of farms was selected for the present study, based on the risk factors evaluated. Even though there is no statistically significant association between the practices evaluated and the incidence of infection, the authors believe that it is important to highlight potential risks that may threaten the outcome of this eradication program. Full article

Maedi-Visna-like genotype A strains and Caprine arthritis encephaltis-like genotype B strains are small ruminant lentiviruses (SRLV) which, for incompletely understood reasons, appear to be more virulent in sheep and goats, respectively. A 9-month in vivo infection experiment using Belgian genotype A and B SRLV strains showed that almost all homologous (genotype A in sheep; genotype B in goats) and heterologous (genotype A in goats; genotype B in sheep) intratracheal inoculations resulted in productive infection. No differences in viremia and time to seroconversion were observed between homologous and heterologous infections. Higher viral loads and more severe lesions in the mammary gland and lung were however detected at 9 months post homologous compared to heterologous infection which coincided with strongly increased IFN-γ mRNA expression levels upon homologous infection. Pepscan analysis revealed a strong antibody response against immune-dominant regions of the capsid and surface proteins upon homologous infection, which was absent after heterologous infection. These results inversely correlated with protection against virus replication in target organs and observed histopathological lesions, and thus require an in-depth evaluation of a potential role of antibody dependent enhancement in SRLV infection. Finally, no horizontal intra- and cross-species SRLV transmission to contact animals was detected. Full article

Small ruminant lentiviruses (SRLVs) infections lead to chronic diseases and remarkable economic losses undermining health and welfare of animals and the sustainability of farms. Early and definite diagnosis of SRLVs infections is the cornerstone for any control and eradication efforts; however, a “gold standard” test and/or diagnostic protocols with extensive applicability have yet to be developed. The main challenges preventing the development of a universally accepted diagnostic tool with sufficient sensitivity, specificity, and accuracy to be integrated in SRLVs control programs are the genetic variability of SRLVs associated with mutations, recombination, and cross-species transmission and the peculiarities of small ruminants’ humoral immune response regarding late seroconversion, as well as intermittent and epitope-specific antibody production. The objectives of this review paper were to summarize the available serological and molecular assays for the diagnosis of SRLVs, to highlight their diagnostic performance emphasizing on advantages and drawbacks of their application, and to discuss current and future perspectives, challenges, limitations and impacts regarding the development of reliable and efficient tools for the diagnosis of SRLVs infections. Full article

Maedi-visna virus (MVV) and caprine arthritis encephalitis virus (CAEV), referred to as small ruminant lentiviruses (SRLVs), belong to the genus Lentivirus of the Retroviridae family. SRLVs infect both sheep and goats, causing significant economic losses and animal welfare damage. Recent findings suggest an association between serological status and allelic variants of different genes such as TMEM154, TLR9, MYD88 and CCR5. The aim of this work was to investigate the role of specific polymorphisms of these genes in SRLVs infection in some sheep flocks in Italy. In addition to those already known, novel variants in the TMEM154 (P7H, I74V, I105V) gene were detected in this study. The risk of infection was determined finding an association between the serological status and polymorphisms P7H, E35K, N70I, I74V, I105V of TMEM154, R447Q, A462S and G520R in TLR9 gene, H176H* and K190K* in MYD88 genes, while no statistical association was observed for the 4-bp deletion of the CCR5 gene. Since no vaccines or treatments have been developed, a genetically based approach could be an innovative strategy to prevent and to control SRLVs infection. Our findings are an important starting point in order to define the genetic resistance profile towards SRLVs infection. Full article