Caprine Arthritis-encephalitis Virus Research Articles

Phylogenetic analysis of small ruminant lentiviruses in Mongolian sheep supports an ancient east-west split for the genotype A.

The ovine maedi-visna virus (MVV) and caprine arthritis-encephalitis virus (CAEV) are small ruminant lentiviruses (SRLVs) with striking genetic and structural similarities. The presence of SRLV in Mongolian sheep and goats was serologically demonstrated more than a decade ago; however, the viral genotype remains unknown. In total, 329 blood samples were collected from two sheep breeds (i.e., Khalkha and Sumber) in Tov, Govisumber, Arkhangay, Dornogovi, Zavkhan, and Sukhbaatar provinces, Mongolia. Serological and phylogenetic analyses were performed regardless of any apparent clinical signs, although most of the animals appeared healthy. All sheep in three of the six provinces were seronegative, whereas the seroprevalence in the Tov, Govisumber, and Zavkhan provinces averaged 7.9%. Genomic DNA from seropositive animals was tested using hemi-nested polymerase chain reaction, and sub-genomic SRLV sequences were determined from nine samples. Mongolian SRLV sequences clustered within the divergent subtype A22, which was previously found only in Fertile Crescent regions, including Lebanon, Jordan, and Iran, where the first sheep-domestication (Ovis aries) occurred. According to the phylogenetic analysis, genotype A has two ancestors from the ancient Fertile Crescent: (1) Turkish strains and (2) Iranian, Jordanian, and Lebanese strains. The first ancestor spread westward, whereas the second spread eastward, ultimately reaching Mongolia.

Detection and Phylogenetic Analysis of Caprine Arthritis Encephalitis Virus Using TaqMan-based qPCR in Eastern China.

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.

High positivity rate of caprine arthritis encephalitis virus in Luzon, the Philippines revealed by nested-polymerase chain reaction assay

High positivity rate of caprine arthritis encephalitis virus in Luzon, the Philippines revealed by nested-polymerase chain reaction assay

The genetic variability of small-ruminant lentiviruses and its impact on tropism, the development of diagnostic tests and vaccines and the effectiveness of control programmes.

Maedi-visna virus and caprine arthritis encephalitis virus are two closely related lentiviruses which cause multisystemic, progressive and persistent infection in goats and sheep. Because these viruses frequently cross the species barrier, they are considered to be one genetic group called small-ruminant lentiviruses (SRLV). They have in vivo tropism mainly for monocytes and macrophages and organ tropism with unknown mechanisms. Typical clinical signs are pneumonia in sheep, arthritis in goats, and mastitis in both species. Infection with SRLV cannot currently be treated or prevented, and control programmes are the only approaches to avoiding its spread. These programmes rely mainly on annual serological testing and elimination of positive animals. However, the high genetic and antigenic variability of SRLV complicate their early and definitive diagnosis. The objective of this review is to summarise the current knowledge of SRLV genetic variation and its implications for tropism, the development of diagnostic tests and vaccines and the effectiveness of control and eradication programmes. Subject literature was selected from the PubMed and the Google Scholar databases. The high genetic diversity of SRLV affects the performance of diagnostic tools and therefore control programmes. For the early and definitive diagnosis of SRLV infection, a combination of serological and molecular tests is suggested. Testing by PCR can also be considered for sub-yearling animals. There are still significant gaps in our knowledge of the epidemiology, immunology and biology of SRLV and their impact on animal production and welfare. This information may aid selection of the most effective SRLV spread reduction measures.

Epizootiological serosurvey on small ruminant lentiviruses: Prevalence, age and breed effects

AbstractIn this study, the prevalence of small ruminant lentivirus, i.e. Maedi-Visna and caprine arthritis encephalitis virus infections in sheep and goat populations were investigated through epizootiological serosurveillance in the Aegean region located in western Türkiye in 2018. A total of 1,840 serum samples (595 goats, 1,245 sheep) were collected from 92 villages in the region and examined by indirect ELISA. Thirty-nine goat and 304 sheep sera were found positive for small ruminant lentivirus antibodies. The prevalence was 24.42% in sheep and 6.55% in goats. An average of 18.64% was found in small ruminants in the Aegean region. The prevalence of small ruminant lentiviruses was found to be higher in Pirlak and Pirlak hybrid sheep and in Saanen and Saanen hybrid goats (P < 0.05). The prevalence was found to increase with age, as it was higher in animals older than 48 months than in the age groups of 0–24 or 25–48 months (P < 0.05). Moreover, the small ruminant lentivirus prevalence was higher in sheep than in goats (P < 0.0001). With the epizootiological approach, this study is expected to contribute to the control and prevention of small ruminant lentivirus infections.

Caprine arthritis encephalitis virus-induced apoptosis associated with brain lesions in naturally infected kids

Acute demyelinating leucoencephalomyelitis was the most conspicuous microscopic change in the brain and spinal cord of kids infected with caprine arthritis encephalitis virus (CAEV). TUNEL positivity and labelling of anti-bax and anti-caspases-3, -8 and -9 were found in a distinct population of glial cells, mainly at the edges of the demyelinated plaques and perivascular areas and, to a lesser extent, in neurons. Double labelling revealed that most of these apoptotic cells in the demyelinated plaques were astrocytes and a few were oligodendroglia. In contrast, expression of bcl-2, an anti-apoptotic protein, was found mainly in neurons of the brainstem and cerebellum and motor neurons of the spinal cord, but was restricted in glial cells. These results suggest that apoptosis plays an important role in the pathogenesis of CAE demyelinating encephalitis.

Isolation and Identification of Caprine Arthritis Encephalitis Virus from Animals in the Republic of Mordovia.

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.

Multiplex assay for the simultaneous detection of antibodies against small ruminant lentivirus, Mycobacterium avium subsp. paratuberculosis, and Brucella melitensis in goats.

Brucellosis, paratuberculosis (PTb), and infections caused by small ruminant lentivirus (SRLV), formerly known as caprine arthritis encephalitis virus (CAEV), adversely affect goat production systems. Nonetheless, commonly used diagnostic tests can only determine one analyte at a time, increasing disease surveillance costs, and limiting their routine use. This study aimed to design and validate a multiplex assay for antibody detection against these three diseases simultaneously. Two recombinant proteins from the SRLV (p16 and gp38), the native hapten of Brucella melitensis, and the paratuberculosis-protoplasmic antigen 3 from Mycobacterium avium subsp. paratuberculosis (MAP) were used to devise and assess a multiplex assay. Conditions for the Luminex® multiplex test were established and validated by sensitivity, specificity, repeatability, and reproducibility parameters. Cut-off points for each antigen were also established. The 3-plex assay had high sensitivity (84%) and specificity (95%). The maximum coefficients of variation were 23.8% and 20.5% for negative and positive control samples, respectively. The p16 and gp38 SRLV antigens are 97% and 95%, similar to the CAEV sequence found in GenBank, respectively. The multiplex test can be effectively used for the simultaneous detection of antibodies against SRLV, MAP and B. melitensis in goats.

Immune response dynamics of recent and chronic small ruminant lentivirus infection in the male reproductive system

The objective of this study was to analyze the immune responses of bucks to small ruminant lentivirus (SRLV) with a focus on the reproductive system of males with recent and chronic infection. A total of 12 bucks were selected, six seronegative and six seropositive with chronic natural infection for more than 18 months (chronic infection group). After selecting the animals, the six seronegative males were intravenously inoculated with caprine arthritis-encephalitis virus (CAEV)-Co viral strain at a titer of 10-5,6 TCID50/mL. After viral inoculation, this group was called the recent infection group and was monitored weekly with the chronically infected group for 180 days with blood serum and seminal plasma Western Blot (WB) analysis. Of the animals with chronic SRLV infection, 18.94% (50/264) showed anti-SRLV antibodies in at least one of the samples, and 81.06% (214/264) were negative. Anti-SRLV antibodies were detected in 27.27% (36/132) of the blood serum samples from this group, while 10.60% (14/132) were reactive in the seminal plasma WB test. The animals inoculated with CAEV-Co became seropositive after the third week of viral inoculation. In this group, 31.06% (41/132) of seminal plasma samples had anti-SRLV antibodies, and of these, 70.73% (29/41) coincided with blood serum results. Of the remaining 29.27% (12/41), the seminal plasma sample of only three animals (RIA2, RIA3, and RIA5) had anti-SRLV antibodies. One of the animals with a recent infection presented anti-SRLV antibodies only in seminal plasma samples, possibly due to virus compartmentalization. Intermittent viral shedding was observed in both biological samples, regardless of the infection stage. The immune response in bucks with recent SRLV infection is more significant than in chronically infected animals. Regardless of the stage of infection, there is a fluctuation in antibody levels, therefore, this creates a risk of false-negative samples when performing the diagnosis.

Genome characterization of the Caprine arthritis-encephalitis virus in China: A retrospective genomic analysis of the earliest Chinese isolates

Caprine arthritis-encephalitis virus (CAEV) is an under-studied virus infecting caprines and ovines worldwide. Over the last four decades, CAEV has spread in China, obtaining genomic data on CAEV strains circulating in China is of importance for developing diagnostic methods and eradicating associated diseases. However, there is limited information on the genome, including characterizations, and the probable origin. This work aimed to characterize Chinese CAEV genomes and population structures. Five CAEV strains isolated from infected dairy goats between 1989 and 1994 in Gansu, Guizhou, Shaanxi, Shandong, and Sichuan provinces were cloned and sequenced. The Chinese CAEV had a 58–93% genome similarities to strains outside of China, and they belong to subgenotype B1. The highest similarity levels (98.3–99.3%) were with two other Chinese strains, and they shared a 91.8–92.3% similarity with the strain Clements (GenBank accession no. NC_001463.1) from outside of China. The Chinese CAEV strains isolated from different provinces over 5 years were still highly homologous and contained unique ancestral population components, indicating that these Chinese strains had a common origin that differed from other known strains. Our results provide genomic data on circulating Chinese CAEV strains and will be useful for future epidemiological investigations and CAEV eradication programs.

O-117 Follow-up scenario’s, including retrospective bulk milk testing, after loss of caprine arthritis encephalitis virus (CAEV) herd accreditation in commercial dairy goat farms

O-117 Follow-up scenario’s, including retrospective bulk milk testing, after loss of caprine arthritis encephalitis virus (CAEV) herd accreditation in commercial dairy goat farms

A Combined Approach for Detection of Ovine Small Ruminant Retrovirus Co-Infections.

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.

Investigation of the Epidemiology of Small Ruminant Lentivirus Infections southeast part of the Marmara region of Turkey

Small ruminant lentiviruses (SRLVs) are viral pathogens that are common in goats and sheep, affect production, and cause significant economic losses in small ruminant breeding. Caprine arthritis encephalitis virus (CAEV) and Maedi-Visna virus (MVV) are prototypes of SRLVs. Both of them affect animal health and welfare in sheep and goats and cause progressive and persistent infections in the small ruminant industry. The present study aimed to reveal the epidemiological status of lentivirus infection in the sheep region in Yalova province located in the southeast part of the Marmara region and determine the circulating genotypes by conducting the sequence analysis of the samples detected positive by a molecular method and molecular characterization of the detected field strains. To that end, 231 sheep blood samples were used between May 2016 and April 2018. Based on sampling results of the PCR test and ELISA tests, 5.62% (13/231) and 5.19% (12/231) positivity rates were found in sheep, respectively. According to the ELISA test results, a significant difference was found in terms of age groups (6 months -1 age, 1-3 age, >3 age) (χ2: 6.01; p=0.04). Furthermore, the sequence analysis of the gag gene region detected the existence of the A genotype of small ruminant lentiviruses in sheep. The data obtained from the study revealed a low seroprevalence course of SRLV infection in the study area in the absence of a systematic disease control program.

Loss of Caprine Arthritis Encephalitis Virus (CAEV) Herd Accreditation: Characteristics, Diagnostic Approach, and Specific Follow-Up Scenarios on Large Dairy Goat Farms.

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.

Serological Evidence of Caprine Arthritis Encephalitis in North Shewa Zone, Ethiopia: Clinical Case Analysis.

IntroductionCaprine arthritis encephalitis (CAE) is a chronic debilitating and economically important viral disease of goats. It is mainly manifested as encephalitis in kids and polyarthritis in adult goats. The present study was conducted to determine the rate of morbidity and mortality due to clinical diseases attributed to infection by Caprine arthritis encephalitis virus (CAEV) and to determine the serological status of CAEV in goat in North Shewa, Ethiopia.MethodsA cross-sectional serological study and a longitudinal clinical case study were conducted. A total of 257 serum samples have been collected from apparently health and clinical cases attributed to CAE infection and tested with the usage of indirect enzyme-linked immunosorbent assays to screen antibodies against CAE. Records have been statistically analyzed by using the chi-square test.ResultsDuring five consecutive years of longitudinal clinical study, a total of 195 clinical diseases of chronic pneumonia, nerve problems, clinical mastitis, and arthritis occurred with prevalence of 99 (50.8%), 57 (29.2%), 27 (13.9%), and 12 (6.2%), respectively. Chronic pneumonia was the highest cause of goat morbidity (50.8%) and mortality (100.0%). Of the total samples tested from clinical cases, 7 (58.3%) were sero-positive for the presence of antibodies against CAEV. The overall seroprevalence of CAE was 4.7%. There has been a significant difference (p < 0.05) in sero-positivity among management system, breeds, and age groups of goats. However, there was no significant variation in sero-positivity between the sexes (p > 0.05) of goats.ConclusionThis finding indicates that CAEV infection exists in the goat flocks in examined localities in Ethiopia. This disease poses serious animal health problems that constrain production with the presence of apparent clinical signs. Further investigations need to be done to explore the seroconversion of CAEV in small ruminants and the associated factors to plan an appropriate eradication program and prevent transmission.

Clinical, Pathological and Molecular Findings in Caprine Arthritis – Encephalitis Virus Infection in Damascus Goats

Abstract Caprine Arthritis-Encephalitis Virus Infection was presented with clinical, pathological, and molecular findings in dairy goats from a breeding unit in Turkey. According to history, 50 of 700 goats and kids showed the clinical signs including anorexia, mastitis, swelling of the joints, lameness, dyspnea and head pressing in the past 2 months. Fifteen and 6 animals were examined clinically and pathologically, respectively. Clinical examination revealed depression, weakness, pneumonia, ataxia and paresis in 15 goats. Histological lesions were composed by a varying degree of interstitial pneumonia, nonsuppurative leukoencephalomyelitis, interstitial nephritis and interstitial myocarditis. Immunohistochemical examinations showed the presence of viral antigen in tubular epithelium, in glial cells and macrophages. In conclusion, this is the first report documenting pathological and molecular changes of Caprine Arthritis-Encephalitis Virus Infection in Turkey in goats.

First study on the molecular prevalence of caprine arthritis encephalitis virus in goats in Babylon, Iraq.

Background and Aim:Caprine arthritis encephalitis virus (CAEV) is a virus that affects goats all over the world and causes enormous economic losses; as a result, screening for the disease is a priority, especially in Iraq. The present study aimed to estimate the prevalence of CAEV in infected goats using the précised PCR method in Babylon, Iraq.Materials and Methods:A total of 85 blood samples from goats aged 1 month to ≥6 years were analyzed for CAEV infections using molecular methods. The polymerase chain reaction primer was designed to amplify a 573 bp region of the proviral pol gene.Results:The CAEV tests revealed that five out of 85 goats were positive for CAEV. There were no significant differences in CAEV infection according to goat sex and significant differences according to age.Conclusion:Based on these results, the present study is the first molecular survey to confirm the current CAEV genome in an Iraqi goat flock.

Low colostrum immunoglobulin G concentration in Saanen dams with seropositive to caprine arthritis encephalitis virus infection without affecting kid growth rate

Low colostrum immunoglobulin G concentration in Saanen dams with seropositive to caprine arthritis encephalitis virus infection without affecting kid growth rate

Risk Factors Associated with the Alpine Multispecies Farming System in the Eradication of CAEV in South Tyrol, Italy.

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.

Initial multi-target approach shows importance of improved caprine arthritis-encephalitis virus control program in Russia for hobbyist goat farms.

Background and Aim:Several reports described the detection of specific caprine arthritis-encephalitis virus (CAEV) antibodies in Russian goat populations, which indicates the circulation of CAEV in Russian goat farms. The aim of this study was to use a multi-target approach to testing with both serological tests and an in-house real-time (RT) molecular test to investigate the prevalence of CAEV in goats from three hobbyist farms in the Republic of Tatarstan, Russia.Materials and Methods:We applied a multi-target approach to testing with both enzyme-linked immunosorbent assay (ELISA) and an in-house RT polymerase chain reaction test to investigate the prevalence of CAEV in goats. Animals from the three hobbyist farms were used in this study. The animals from two farms (n=13 for F1 and n=8 for F2) had clinical signs of arthritis and mastitis. In the third farm (n=15 for F3), all goats were home-bred and had no contact with imported animals.Results:CAEV antibodies (ELISA targets TM env and gag genes) were detected in serum samples from two farms (F1 and F2), indicating seroprevalence of 87.50-92.31%. Specific CAEV antibodies were also detected in milk samples. CAEV proviral DNA was detected in 53.85-62.50%. The results from all tests performed in the third farm (F3) were negative, indicating that all tests were 100% specific.Conclusion:The results showed that CAEV is circulating and present in small hobbyist goat farms in Russia. Serological and molecular tests could be important for programs to control and eradicate CAEV in Russia for hobbyist goat farms.