Isolation of caprine arthritis-encephalitis virus from a goat

The Prevalence of Histopathological Features of Pneumonia in Goats with Symptomatic Caprine Arthritis-Encephalitis

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.

The development and evaluation of an ELISA for the detection of antibodies to caprine arthritis-encephalitis virus in goat sera

An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of antibodies to caprine arthritis encephalitis virus (CAEV) in goat sera. The system was evaluated using some 1500 sera from flocks of known clinical history. From this data the interpretation limits of the system were determined. The ELISA system was compared with a gel precipitin test using 5800 sera. Of the positive sera, ELISA detected 97.3% and AGPT 61%. Further evaluation was made using 60 sera of known CAEV reactivity from the USA, and results agreed 100%. Indications are that antibody to the envelope glycoprotein gp135 is being detected. The ELISA system is more sensitive than the precipitin test and is presently being used in a CAEV flock accreditation scheme.

Control and eradication of animal diseases in New Zealand

New Zealand is free from all the major epidemic (Office International des Epizooties List A) diseases of animals and other important diseases, such as rabies and the transmissible spongiform encephalopathies. The once endemic conditions of sheep scab (Psoroptes ovis), bovine brucellosis (Brucella abortus), hydatids (Echinococcus granulosus) and Aujeszky's disease have been eradicated. Anthrax (Bacillus anthracis) is no longer considered endemic and Pullorum disease (Salmonella Pullorum) has effectively been eradicated from commercial poultry flocks. There are current control programmes for bovine tuberculosis (Mycobacterium bovis), enzootic bovine leucosis in dairy cattle, infectious bursal disease, ovine epididymitis (Brucella ovis), and caprine arthritis encephalitis. Historically, incursions by three important non-endemic diseases, contagious bovine pleuropneumonia, classical swine fever and scrapie, have been successfully eliminated. Any new occurrence of a serious exotic disease would be dealt with swiftly using powerful legislative authorities available for the purpose.

Application of subjective methods to the determination of the likelihood and consequences of the entry of foot-and-mouth disease into New Zealand

New Zealand has a history of continuous freedom from foot-and-mouth disease and relies on a two-tier system of surveillance to maintain this status. The first involves border control procedures and stringent importation standards, and the second is an exotic disease and pest response programme. As part of an economic evaluation comparing the exotic disease and pest response programme against a hypothetical lower grade ;measured response programme subjective judgements of the risks involved were required. Twenty-eight selected animal health professionals, predominantly veterinarians, were posted a questionnaire that used three techniques (single point estimates, three point estimates and elicitation methods) to determine the risk components in a foot-and-mouth disease outbreak. The two key variables were the probability of an outbreak in New Zealand, and the number of secondary properties to which the disease spread during the epidemic. A Delphi conference of ten selected participants then focused mainly on the two key variables, with a second round postal extension to this group for the first variable. The individual data sets were then analysed and combined using a stochastic simulation technique. The final mean probability of an outbreak was about once in 50 years (0.0199). The mean numbers of farms to which disease would spread during an epidemic under the existing exotic disease and pest response programme, a measured response programme which allowed vaccination and a measured response programme which excluded vaccination were estimated to be 61, 478 and 2230 respectively. The policy implications arising from the quantification of these two key variables are that more expenditure on preparedness is justifiable and current resource planning is barely adequate.

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.

Caprine arthritis-encephalitis syndrome (CAE): a review

Caprine arthritis-encephalitis syndrome (CAE) is a viral disease of domestic goats characterized by chronic proliferative synovitis and periarthritis of adult goats while acute afebrile leukoencephalomyelitis is characteristic in goat kids. The causative agent, a Lentivirus, is transmitted from adult goats to kids via the colostrum or lateral transmission also occurs. The CAE virus is worldwide in distribution. All breeds and ages of goats are susceptible to infection, and once established it persists throughout the animal's life. A diagnosis can be based on the clinical signs, pathological changes, and demonstration of serum antibody levels. A vaccine is not available. Control or eradication of the disease is based on periodic serological testing, culling of all CAE antibody-positive animals, and separation of kids from adults following birth.

Progressive interstitial pneumonia in goats

Seven Anglo-Nubian goats, 5 months to 3 1/2 years old, developed clinical signs of increased respiratory rate, weight loss and exercise intolerance. Post-mortem examination of the goats revealed extensive consolidation of the lungs involving all lobes. Lesions, consisting of peribronchial and perivascular lymphoid cuffing, accumulations of homogeneous eosinophilic material in alveolar spaces, alveolar epithelialisation and thickening of alveolar septa as a result of lymphocytic infiltration, were detected histologically. A syncytial forming virus was consistently isolated from affected animals in explant cultures of lung, synovial membrane and choroid plexus. This agent had similar growth characteristics to the caprine arthritis-encephalitis (CAE) virus and the possible relationship between the respiratory disease and the diseases caused by the CAE virus is discussed.