Caprine arthritis-encephalitis syndrome (CAE): a review

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

Introduction

Caprine 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.

Methods

A 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.

Results

During 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.

Conclusion

This 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.

Further Insights Into Caprine Arthritis Encephalitis (CAE): The Current Status of Seroprevalence Among Small Ruminants in Two Selected States of Peninsular Malaysia

Caprine arthritis-encephalitis virus (CAEV) is a member of the genus lentivirus causing caprine arthritis-encephalitis (CAE), a chronic inflammatory condition affecting the lungs, joints, udder and central nervous system of small ruminants such as sheep and goats. CAE is distributed worldwide and is recognised as a significant cause of morbidity and decreased milk production in dairy goats. Earlier studies highlighted the clinicopathological features and supplied preliminary serological evidence for the existence of CAE among selected goat herds in Malaysia. Therefore, this study aims to provide further insights into the seroprevalence and contributing factors of CAE among sheep and goat herds in two states of Peninsular Malaysia. The blood samples and biodata were randomly collected from a total of 262 individual sheep (40) and goat (222) in seven smallholder farms. Blood sera were tested for specific anti-CAEV antibodies using Qayee-Bio CAEV sandwich-ELISA test kits according to standard procedures. Our results of the study revealed 21.4% (95% CI: 15.8-28.6) apparent and 20.6% (95% CI: 14.5-27.8) true seroprevalence with significant differences (p < 0.05) in seroconversion rates between the states, farms, production systems and breeds of small ruminants. The prevalence of CAE in the Malaysian Peninsular is a potential threat to the small ruminant industry and developing agricultural economy. Further studies are required to determine the genetic characteristics, distribution and risk factors of CAEV for effective prevention and control in Malaysia.

Alterações histopatológicas da glândula mamária e qualidade do leite de cabras naturalmente infectadas com o CAEV

Avaliou-se a influência do vírus da CAE nas características físico-químicas de amostras de leite de 54 cabras, sem predileção racial, distribuindo-as em dois grupos: cabras positivas e negativas para o teste de imunodifusão em gel de agarose. As amostras de leite foram submetidas à análise ultrassônica para obtenção de parâmetros físico-químicos - gordura, extrato seco, proteínas, lactose e densidade; realização de microbiologia - bactérias mesófilas (UCF/mL). Foram coletadas amostras de tecido mamário para exame histopatológico e imunohistoquímica. Não houve diferença significativa das características avaliadas entre os dois grupos; no microbiológico, não houve relação direta da presença de mesófilas associada à infecção pelo CAEV. Na histopatologia, observaram-se áreas com infiltração celular de monócitos, polimorfonucleares, plasmócitos, fibrose, ausência de morfologia normal do parênquima mamário, denotando processo inflamatório crônico; e foi confirmada a presença do vírus na glândula pela imunohistoquímica. Os resultados não mostraram relação direta da incidência da CAE como fator negativo no desenvolvimento do rebanho.

Development of a loop-mediated isothermal amplification method for rapid detection of caprine arthritis-encephalitis virus proviral DNA

A rapid detection assay based on loop-mediated isothermal amplification (LAMP) has been developed for detecting caprine arthritis-encephalitis (CAEV) proviral DNA. The LAMP assay utilized a set of five primers designed against highly conserved sequences located within the p25 gene region. The assay successfully detected CAEV proviral DNA in total DNA extracts originating from cell culture, whole blood samples and separated PBMCs. There was no cross-reaction with the negative control. Amplification was monitored using a Loopamp real-time turbidimeter; turbidity and the corresponding time were recorded. Amplification from CAEV-Shanxi DNA was detected as early as 17 min, with a maximum sensitivity of 0.0001 TCID(50), reached at 32 min. Sixty-eight animal blood samples were tested using AGID, PCR and LAMP assay, and the positive rates were 30.9 %, 33.8 % and 47.1 %, respectively. Whole blood can be used directly, eliminating the need for separation of PBMCs and nucleic acid extraction, reducing the overall procedure time to approximately 80 min. Therefore, the LAMP assay provides a specific and sensitive means for detecting CAEV proviral DNA in a simple, fast, and cost-effective manner and should be useful in eradication programs and epidemiological studies. Furthermore, the LAMP assay can be performed in less-well-equipped laboratories as well as in the field.

Choroid Plexus Carcinoma in a Goat

A 15-year-old female goat suddenly developed right-sided head tilting with anorexia and depression. Post-mortem examination of the brain revealed a large, unilateral, well-demarcated, intraventricular neoplasm which was diagnosed as a choroid plexus carcinoma. The neoplasm, which occupied about 75% of the left lateral ventricle, led to unilateral obstructive hydrocephalus and invaded the white and grey matter of the left piriform lobe, with focal subarachnoid spread and meningeal implantation. Histopathological examination revealed loss of branching papillary architecture, invasive growth, a high mitotic index and marked necrosis in the undifferentiated areas of the tumour. Neoplastic cells expressed vimentin and, multifocally, broad spectrum cytokeratins, but were negative for GFAP, NSE and Sl00 antigen. This is the first report of a choroid plexus carcinoma in a goat.

[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.

Caprine arthritis-encephalitis virus infection of goats in South Australia

Caprine arthritis-encephalitis virus (CAEV) infection of dairy goats was shown by virus isolation and serology to be widespread in South Australia. CAEV was isolated at necropsy from 24 of 27 dairy goats with swollen joints from 13 herds, and from 9 of 30 liver dairy goats in 7 herds. Virus was isolated most frequently from synovial membranes, and occasionally from mammary glands, mammary lymph nodes, choroid plexus, lungs, spleen, bone marrow, salivary glands, leucocytes, synovial fluid and milk. Antibody to CAEV was detected in the serum of 13 of 17 of the necropsied goats tested in a single-line gel diffusion test, and in another 3 retested with a modified double-line technique. Serum antibody was also demonstrated in 61 of 77 dairy goat herds, many with histories of arthritis. In 1984 to 1986 the annual number of serologically positive serums and proportions of the numbers tested were 134 (40%), 121 (45%) and 42 (18%), respectively. CAEV was isolated from leucocytes of 8 live goats in 6 of these herds. In fibre goats antibody was detected in the serum of 25 Angora and 19 crossbreds (0.1%) from the 33,279 Angora, 1,705 Cashmere, 8,715 crossbred and 904 feral goats tested.

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.